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Alteration of functional connectivity in patients with Alzheimer’s disease revealed by resting-state functional magnetic resonance imaging 预览
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作者 Jie Zhao Yu-Hang Du +2 位作者 Xue-Tong Ding Xue-Hu Wang Guo-Zun Men 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第2期285-292,共8页
The main symptom of patients with Alzheimer’s disease is cognitive dysfunction. Alzheimer’s disease is mainly diagnosed based on changes in brain structure. Functional connectivity reflects the synchrony of function... The main symptom of patients with Alzheimer’s disease is cognitive dysfunction. Alzheimer’s disease is mainly diagnosed based on changes in brain structure. Functional connectivity reflects the synchrony of functional activities between non-adjacent brain regions, and changes in functional connectivity appear earlier than those in brain structure. In this study, we detected resting-state functional connectivity changes in patients with Alzheimer’s disease to provide reference evidence for disease prediction. Functional magnetic resonance imaging data from patients with Alzheimer’s disease were used to show whether particular white and gray matter areas had certain functional connectivity patterns and if these patterns changed with disease severity. In nine white and corresponding gray matter regions, correlations of normal cognition, early mild cognitive impairment, and late mild cognitive impairment with blood oxygen level-dependent signal time series were detected. Average correlation coefficient analysis indicated functional connectivity patterns between white and gray matter in the resting state of patients with Alzheimer’s disease. Functional connectivity pattern variation correlated with disease severity, with some regions having relatively strong or weak correlations. We found that the correlation coefficients of five regions were 0.3–0.5 in patients with normal cognition and 0–0.2 in those developing Alzheimer’s disease. Moreover, in the other four regions, the range increased to 0.45–0.7 with increasing cognitive impairment. In some white and gray matter areas, there were specific connectivity patterns. Changes in regional white and gray matter connectivity patterns may be used to predict Alzheimer’s disease;however, detailed information on specific connectivity patterns is needed. All study data were obtained from the Alzheimer’s Disease Neuroimaging Initiative Library of the Image and Data Archive Database. 展开更多
关键词 Alzheimer's disease blood oxygen level-dependent signal correlation coefficient FUNCTIONAL connectivity pattern FUNCTIONAL magnetic resonance imaging GRAY MATTER RESTING state white MATTER
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Relationship between MRI perfusion and clinical severity in multiple sclerosis 预览
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作者 Maria Marcella Laganà Laura Pelizzari Francesca Baglio 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第4期646-652,共7页
Perfusion alterations within several brain regions have been shown in multiple sclerosis patients using different magnetic resonance imaging(MRI)techniques.Furthermore,MRI-derived brain perfusion metrics have been inv... Perfusion alterations within several brain regions have been shown in multiple sclerosis patients using different magnetic resonance imaging(MRI)techniques.Furthermore,MRI-derived brain perfusion metrics have been investigated in association with multiple sclerosis phenotypes,physical disability,and cognitive impairment.However,a review focused on these aspects is still missing.Our aim was to review all the studies investigating the relationship between perfusion MRI and clinical severity during the last fifteen years to understand the clinical relevance of these findings.Perfusion differences among phenotypes were observed both with 1.5T and 3T scanners,with progressive multiple sclerosis presenting with lower perfusion values than relapsing-remitting multiple sclerosis patients.However,only 3T scanners showed a statistically significant distinction.Controversial results about the association between MRI-derived perfusion metrics and physical disability scores were found.However,the majority of the studies showed that lower brain perfusion and longer transit time are associated with more severe physical disability and worse cognitive performances. 展开更多
关键词 brain PERFUSION cerebral blood flow cognition DISABILITY magnetic resonance imaging MRI multiple SCLEROSIS PHENOTYPES PROGRESSIVE relapsing remitting
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Three-dimensional bioprinting collagen/silk fibroin scaffold combined with neural stem cells promotes nerve regeneration after spinal cord injury 预览
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作者 Ji-Peng Jiang Xiao-Yin Liu +9 位作者 Fei Zhao Xiang Zhu Xiao-Yin Li Xue-Gang Niu Zi-Tong Yao Chen Dai Hui-You Xu Ke Ma Xu-Yi Chen Sai Zhang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第5期959-968,共10页
Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods... Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods for neural regeneration.This study was designed to fabricate a type of three-dimensional collagen/silk fibroin scaffold (3D-CF) with cavities that simulate the anatomy of normal spinal cord.This scaffold allows cell growth in vitro and in vivo.To observe the effects of combined transplantation of neural stem cells (NSCs) and 3D-CF on the repair of spinal cord injury.Forty Sprague-Dawley rats were divided into four groups: sham (only laminectomy was performed),spinal cord injury (transection injury of T10 spinal cord without any transplantation),3D-CF (3D scaffold was transplanted into the local injured cavity),and 3D-CF + NSCs (3D scaffold co-cultured with NSCs was transplanted into the local injured cavity.Neuroelectrophysiology,imaging,hematoxylin-eosin staining,argentaffin staining,immunofluorescence staining,and western blot assay were performed.Apart from the sham group,neurological scores were significantly higher in the 3D-CF + NSCs group compared with other groups.Moreover,latency of the 3D-CF + NSCs group was significantly reduced,while the amplitude was significantly increased in motor evoked potential tests.The results of magnetic resonance imaging and diffusion tensor imaging showed that both spinal cord continuity and the filling of injury cavity were the best in the 3D-CF + NSCs group.Moreover,regenerative axons were abundant and glial scarring was reduced in the 3D-CF + NSCs group compared with other groups.These results confirm that implantation of 3D-CF combined with NSCs can promote the repair of injured spinal cord.This study was approved by the Institutional Animal Care and Use Committee of People’s Armed Police Force Medical Center in 2017 (approval No.2017-0007.2). 展开更多
关键词 3D BIOPRINTING COLLAGEN diffusion tensor IMAGING functional recovery magnetic resonance IMAGING nerve REGENERATION NEURAL REGENERATION NEURAL stem cell SCAFFOLD silk fibroin spinal cord injury
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Evolving role of magnetic resonance techniques in primary sclerosing cholangitis 预览
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作者 Emmanuel A Selvaraj Emma L Culver +3 位作者 Helen Bungay Adam Bailey Roger W Chapman Michael Pavlides 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第6期644-658,共15页
Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis(PSC).In addition to serum and h... Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis(PSC).In addition to serum and histological biomarkers,there has been much recent interest in developing imaging biomarkers that can predict disease course and clinical outcomes in PSC.Magnetic resonance imaging/magnetic resonance cholangiopancreatography(MRI/MRCP)continue to play a central role in the diagnosis and follow-up of PSC patients.Magnetic resonance(MR)techniques have undergone significant advancement over the last three decades both in MR data acquisition and interpretation.The progression from a qualitative to quantitative approach in MR acquisition techniques and data interpretation,offers the opportunity for the development of objective and reproducible imaging biomarkers that can potentially be incorporated as an additional endpoint in clinical trials.This review article will discuss how the role of MR techniques have evolved over the last three decades from emerging as an alternative diagnostic tool to endoscopic retrograde cholangiopancreatography,to being instrumental in the ongoing search for imaging biomarker of disease stage,progression and prognosis in PSC. 展开更多
关键词 Primary SCLEROSING CHOLANGITIS MAGNETIC RESONANCE IMAGING MAGNETIC RESONANCE CHOLANGIOPANCREATOGRAPHY MAGNETIC RESONANCE elastography Diffusion MAGNETIC RESONANCE IMAGING Endoscopic retrograde CHOLANGIOPANCREATOGRAPHY
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Evaluation of tumor response to antiangiogenic therapy in patients with recurrent gliomas using contrast-enhanced perfusion-weighted magnetic resonance imaging techniques: A meta-analysis 预览
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作者 Akanganyira Kasenene Aju Baidya +1 位作者 Salman Shams Hai-Bo Xu 《世界荟萃分析杂志》 2019年第2期51-65,共15页
BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tu... BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tumor. However, the treatment response is observed only in a fraction of patients due to the partial radiological response secondary to stabilization of abnormal vessels which does not essentially indicate a true antitumor effect. Perfusion-weighted magnetic resonance imaging (PWMRI) techniques have shown implicitness as a strong imaging biomarker for gliomas since they give hemodynamic information of blood vessels. Hence, there is a rapid expansion of PW-MRI related studies and clinical applications. AIM To determine the diagnostic performance of PW-MRI techniques including:(A) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI);and (B) dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) for evaluating response to antiangiogenic therapy in patients with recurrent gliomas. METHODS Databases such as PubMed (MEDLINE included), EMBASE, and Google Scholar were searched for relevant original articles. The included studies were assessed for methodological quality with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Medical imaging follow-up or histopathological analysis was used as the reference standard. The data were extracted by two reviewers independently, and then the sensitivity, specificity, summary receiver operating characteristic curve, area under the curve (AUC), and heterogeneity were calculated using Meta-Disc 1.4 software.RESULTS This study analyzed a total of six articles. The overall sensitivity for DCE-MRI and DSC-MRI was 0.69 [95% confidence interval (CI): 0.53-0.82], and the specificity was 0.99 (95%CI: 0.93-1) by a random effects model (DerSimonianee- Laird model). The likelihood ratio (LR)+, LR-, and diagnostic odds ratio (DOR) were 12.84 (4.54-36.28), 0.35 (0.22-0.53), and 24.44 (7.19-83.06), respectively. The AUC (± SE) was 0.9921 (± 0.0120), 展开更多
关键词 Glioma Perfusion-weighted MAGNETIC RESONANCE IMAGING DYNAMIC contrastenhanced MAGNETIC RESONANCE IMAGING DYNAMIC susceptibility contrast MAGNETIC RESONANCE IMAGING Anti-vascular endothelial growth factor ANTIANGIOGENIC Metaanalysis
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固有频率与共振频率影响因素及实验研究 预览
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作者 张枫茁 顾吉林 +2 位作者 李欣阳 杨青 王震 《大学物理实验》 2019年第2期37-41,共5页
从实验室常见的实验仪器烧杯入手,先测量烧杯的固有频率,然后在测得的固有频率附近寻找烧杯的共振频率,并研究了相关参量对烧杯系统共振频率的影响。实验结论表明:系统的共振频率与烧杯口径、烧杯所加液体质量以及烧杯中所盛放液体的表... 从实验室常见的实验仪器烧杯入手,先测量烧杯的固有频率,然后在测得的固有频率附近寻找烧杯的共振频率,并研究了相关参量对烧杯系统共振频率的影响。实验结论表明:系统的共振频率与烧杯口径、烧杯所加液体质量以及烧杯中所盛放液体的表面张力有关。当烧杯中所加液体体积一定时,烧杯系统的共振频率与烧杯的口径成反比;当烧杯口径一定时,烧杯系统的共振频率与所加液体质量成反比;在使用相同口径的烧杯,并加入相同质量的甘油和水时,烧杯中所盛放液体的表面张力越大,共振频率越大。 展开更多
关键词 共振 固有频率 烧杯系统 共振频率 实验
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Imaging plaque inflammation in asymptomatic cocaine addicted individuals with simultaneous positron emission tomography/magnetic resonance imaging 预览
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作者 Keren Bachi Venkatesh Mani +4 位作者 Audrey E Kaufman Nadia Alie Rita Z Goldstein Zahi A Fayad Nelly Alia-Klein 《世界放射学杂志:英文版(电子版)》 2019年第5期62-73,共12页
BACKGROUND Chronic cocaine use is associated with stroke, coronary artery disease and myocardial infarction, resulting in severe impairments or sudden mortality. In the absence of clear cardiovascular symptoms, indivi... BACKGROUND Chronic cocaine use is associated with stroke, coronary artery disease and myocardial infarction, resulting in severe impairments or sudden mortality. In the absence of clear cardiovascular symptoms, individuals with cocaine use disorder (iCUD) seeking addiction treatment receive mostly psychotherapy and psychiatric pharmacotherapy, with no attention to vascular disease (i.e., atherosclerosis). Little is known about the pre-clinical signs of cardiovascular risk in iCUD and early signs of vascular disease are undetected in this underserved population. AIM To assess inflammation, plaque burden and plaque composition in iCUD aiming to detect markers of atherosclerosis and vascular disease. METHODS The bilateral carotid arteries were imaged with positron emission tomography/magnetic resonance imaging (PET/MRI) in iCUD asymptomatic for cardiovascular disease, healthy controls, and individuals with cardiovascular risk. PET with 18F-fluorodeoxyglucose (18F-FDG) evaluated vascular inflammation and 3-D dark-blood MRI assessed plaque burden including wall area and thickness. Drug use and severity of addiction were assessed with standardized instruments. RESULTS The majority of iCUD and controls had carotid FDG-PET signal greater than 1.6 but lower than 3, indicating the presence of mild to moderate inflammation. However, the MRI measure of wall structure was thicker in iCUD as compared to the controls and cardiovascular risk group, indicating greater carotid plaque burden. iCUD had larger wall area as compared to the healthy controls but not as compared to the cardiovascular risk group, indicating structural wall similarities between the non-control study groups. In iCUD, wall area correlated with greater cocaine withdrawal and craving. CONCLUSION These preliminary results show markers of carotid artery disease burden in cardiovascular disease-asymptomatic iCUD. Broader trials are warranted to develop protocols for early detection of cardiovascular risk and preventive intervention in iCUD. 展开更多
关键词 3-D dark-blood magnetic resonance imaging 18F-fluorodeoxyglucose POSITRON emission TOMOGRAPHY SIMULTANEOUS POSITRON emission TOMOGRAPHY Magnetic resonance Substance use disorder COCAINE addiction Atherosclerosis PLAQUE burden Vascular INFLAMMATION
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Analysis of in-plane 1:1:1 internal resonance of a double cable-stayed shallow arch model with cables’ external excitations 预览
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作者 Yunyue CONG Houjun KANG Tieding GUO 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第7期977-1000,共24页
The nonlinear dynamic behaviors of a double cable-stayed shallow arch model are investigated under the one-to-one-to-one internal resonance among the lowest modes of cables and the shallow arch and external primary re... The nonlinear dynamic behaviors of a double cable-stayed shallow arch model are investigated under the one-to-one-to-one internal resonance among the lowest modes of cables and the shallow arch and external primary resonance of cables. The in-plane governing equations of the system are obtained when the harmonic excitation is applied to cables. The excitation mechanism due to the angle-variation of cable tension during motion is newly introduced. Galerkin’s method and the multi-scale method are used to obtain ordinary differential equations (ODEs) of the system and their modulation equations, respectively. Frequency- and force-response curves are used to explore dynamic behaviors of the system when harmonic excitations are symmetrically and asymmetrically applied to cables. More importantly, comparisons of frequency-response curves of the system obtained by two types of trial functions, namely, a common sine function and an exact piecewise function, of the shallow arch in Galerkin’s integration are conducted. The analysis shows that the two results have a slight difference;however, they both have sufficient accuracy to solve the proposed dynamic system. 展开更多
关键词 nonlinear dynamics CABLE-STAYED system internal RESONANCE primary RESONANCE MULTI-SCALE method
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Instability inspection of parametric vibrating rectangular Mindlin plates lying on Winkler foundations under periodic loading of moving masses 预览
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作者 E.Torkan M.Pirmoradian M.Hashemian 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第1期242-263,I0007共23页
Parametric resonance is one of the most important issues in the study of dynamical behavior of structures. In this paper, dynamic instability of a moderately thick rectangular plate on an elastic foundation is investi... Parametric resonance is one of the most important issues in the study of dynamical behavior of structures. In this paper, dynamic instability of a moderately thick rectangular plate on an elastic foundation is investigated in the case of parametric and external resonances due to periodic passage of moving masses. The governing coupled partial differential equations (PDEs) of the system, with consideration of the first-order shear deformation theory (FSDT) or Mindlin plate theory, are presented and they are reduced to a set of ordinary differential equations (ODEs) with time-dependent coefficients using the Galerkin procedure. All inertial components of the moving masses are adopted in the dynamical formulation. Instability survey is carried out for three different loading trajectories considerably interested in many practical applications of the issue, i.e. rectilinear, diagonal and orbiting trajectories. In order to analyze the resonance conditions, the incremental harmonic balance (IHB) method is introduced to calculate instability boundaries, as well as external resonance curves in parameters plane. A comprehensive study is done to assess effects of thickness ratio and foundation stiffness on the resonance conditions. It is found that an increase in the plate's thickness ratio leads to a reduction in values of critical parameters. Moreover, it is observed that in creasing the foundation stiffness moves the in stability regions and resona nee curves to higher frequencies of the moving masses and also leads to further stability of the parametrically excited system at lower frequencies. Time response simulations done via Runge-Kutta method confirmed the results predicted by IHB method. 展开更多
关键词 Mass-plate interaction MINDLIN plate PARAMETRIC RESONANCE External RESONANCE INCREMENTAL HARMONIC balanee method
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Dynamical modeling and non-planar coupled behavior of inclined CFRP cables under simultaneous internal and external resonances 预览
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作者 Houjun KANG Tieding GUO +2 位作者 Weidong ZHU Junyi SU Bingyu ZHAO 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第5期649-678,共30页
A dynamic model for an inclined carbon fiber reinforced polymer (CFRP) cable is established, and the linear and nonlinear dynamic behaviors are investigated in detail. The partial differential equations for both the i... A dynamic model for an inclined carbon fiber reinforced polymer (CFRP) cable is established, and the linear and nonlinear dynamic behaviors are investigated in detail. The partial differential equations for both the in-plane and out-of-plane dynamics of the inclined CFRP cable are obtained by Hamilton’s principle. The linear eigenvalues are explored theoretically. Then, the ordinary differential equations for analyzing the dynamic behaviors are obtained by the Galerkin integral and dimensionless treatments. The steady-state solutions of the nonlinear equations are obtained by the multiple scale method (MSM) and the Newton-Raphson method. The frequency- and force-response curves are used to investigate the dynamic behaviors of the inclined CFRP cable under simultaneous internal (between the lowest in-plane and out-of-plane modes) and external resonances, i.e., the primary resonances induced by the excitations of the in-plane mode, the out-of-plane mode, and both the in-plane mode and the out-of-plane mode, respectively. The effects of the key parameters, e.g., Young’s modulus, the excitation amplitude, and the frequency on the dynamic behaviors, are discussed in detail. Some interesting phenomena and results are observed and concluded. 展开更多
关键词 inclined carbon fiber reinforced polymer (CFRP) cable BIFURCATION nonlinear dynamics INTERNAL RESONANCE EXTERNAL RESONANCE
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Enhanced organic solar cell performance: Multiple surface plasmon resonance and incorporation of silver nanodisks into a grating‐structure electrode 预览
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作者 Thitirat Putnin Chutiparn Lertvachirapaiboon +5 位作者 Ryousuke Ishikawa Kazunari Shinbo Keizo Kato Sanong Ekgasit Kontad Ounnunkad Akira Baba 《光电进展(英文)》 2019年第7期7-20,共14页
In this study, plasmonic nanostructures were examined to enhance the light harvesting of organic thin-film solar cells (OSCs) by multiple surface plasmon resonance (SPR) phenomena originating from the grating-coupled ... In this study, plasmonic nanostructures were examined to enhance the light harvesting of organic thin-film solar cells (OSCs) by multiple surface plasmon resonance (SPR) phenomena originating from the grating-coupled configuration with a Blu-ray Disc recordable (BD-R)-imprinted aluminum (Al) grating structure and the incorporation of a series of silver nanodisks (Ag NDs). The devices with such a configuration maximize the light utilization inside OSCs via light absorption, light scattering, and trapping via multiple surface plasmon resonances. Different types and sizes of metallic nanoparticles (NPs), i.e., gold nanoparticles (Au NPs), Ag nanospheres (Ag NSs), and Ag NDs, were used, which were blended separately in a PEDOT:PSS hole transport layer (HTL). The device structure comprised of grating- imprinted-Al/P3HT:PCBM/Ag ND:PEDOT:PSS/ITO. Results obtained from the J–V curves revealed that the power conversion efficiency (PCE) of grating-structured Al/P3HT:PCBM/PEDOT:PSS/ITO is 3.16%;this value is ~6% higher than that of a flat substrate. On the other hand, devices with flat Al and incorporated Au NPs, Ag NSs, or Ag NDs in the HTL exhibited PCEs ranging from 3.15% to 3.37%. Furthermore, OSCs with an Al grating substrate were developed by the incorporation of the Ag ND series into the PEDOT:PSS layer. Compared with that of a reference device, the PCEs of the devices increased to 3.32%–3.59%(11%–20% improvement), indicating that the light absorption enhancement at the active layer corresponds to the grating-coupled surface plasmon resonance and localized surface plasmon resonance excitations with strong near-field distributions penetrating into the active layer leading to higher efficiencies and subsequent better current generation. 展开更多
关键词 grating-coupled SURFACE PLASMON RESONANCE LOCALIZED SURFACE PLASMON RESONANCE Ag NANODISKS organic solar cells imprinted GRATING
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Accuracy of multi-echo Dixon sequence in quantification of hepatic steatosis in Chinese children and adolescents 预览
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作者 Yu-Zhen Zhao Yun-Gen Gan +7 位作者 Jian-Li Zhou Jia-Qi Liu Wei-Guo Cao Shu-Mei Cheng Da-Ming Bai Meng-Zhu Wang Fang-Qin Gao Shao-Ming Zhou 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第12期1513-1523,共11页
BACKGROUND Nonalcoholic fatty liver disease (NAFLD) is currently the outstanding cause of chronic liver disease in children and adolescents, especially in overweight and obese groups. Liver biopsy is the reference sta... BACKGROUND Nonalcoholic fatty liver disease (NAFLD) is currently the outstanding cause of chronic liver disease in children and adolescents, especially in overweight and obese groups. Liver biopsy is the reference standard to diagnose NAFLD but invasive, thus it is not the best choice in clinical diagnosis and follow-up. Magnetic resonance (MR) is widely used in clinical trials to noninvasively quantify liver fat content in adults and children in foreign countries. While currently, it is rarely used in Chinese children and adolescents. We postulated that quantifying hepatic steatosis by MR could be extended to children and adolescents in China. AIM To investigate the accuracy of MR imaging (MRI) in quantifying liver fat with MR spectroscopy (MRS) as a reference. A secondary goal was to assess the prevalence of NAFLD in overweight and obese Chinese children and adolescents. METHODS There were 86 children and adolescents enrolled in this study, including 65 overweight and obese children and 21 healthy children. The participants underwent MRI and MRS. MRI and MRS were performed using multi-echo Dixon and HISTO sequences, respectively, to calculate hepatic proton density fat fraction (PDFF). Hepatic steatosis was diagnosed using MRS-PDFF>5% as the threshold. Spearman’s analysis was used to evaluate the correlation between MRI and MRS. The agreement between these two methods was assessed by Bland- Altman analysis. RESULTS The MRI-PDFF in the MRS region of interest and the entire liver was 9.9%±10.3% with a range of 0.3%-39.9%, and 10.6%±9.4% with a range of 1.9%-38.9%, respectively. The MRS-PDFF was 9.1%±10.0%, with a range of 0.5%-37.8%. The incidence of hepatic steatosis detected by MRS-PDFF was 46.5%(40/86) of all participants, all of whom belonged to the overweight and obese group. Spearman’s analysis indicated an excellent correlation between multi-echo Dixon and MRS (r>0.9, P<0.01). Bland-Altman analysis also demonstrated a good agreement between these two methods. CONCLUSION Multi-echo Dixon shows an exc 展开更多
关键词 NONALCOHOLIC FATTY liver disease MAGNETIC RESONANCE imaging MAGNETIC RESONANCE spectroscopy Children and adolescents Hepatic STEATOSIS
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Adult-onset mitochondrial encephalopathy in association with the MT-ND3 T10158C mutation exhibits unique characteristics: A case report 预览
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作者 Xiao-Li Fu Xiang-Xue Zhou +1 位作者 Zhu Shi Wei-Cheng Zheng 《世界临床病例杂志》 2019年第9期1066-1072,共7页
BACKGROUND Mitochondrial diseases are a heterogenous group of multisystemic disorders caused by genetic mutations affecting mitochondrial oxidation function. Brain involvement is commonly found in most cases but rarel... BACKGROUND Mitochondrial diseases are a heterogenous group of multisystemic disorders caused by genetic mutations affecting mitochondrial oxidation function. Brain involvement is commonly found in most cases but rarely as the unique clinical manifestation. Since the knowledge of its clinical manifestation combined with genetic testing is important for preventing misdiagnosis and delay in treatment, we report here how we diagnosed and managed a very unusual case of mitochondrial encephalopathy. CASE SUMMARY We report a 52-year-old woman with recurrent stroke-like episodes carrying the m.10158T>C mutation in the MT-ND3 gene, which is also responsible for fatal infant-onset Leigh syndrome. Despite the common mutation, the present case featured a distinct clinical and neuroimaging manifestation from Leigh syndrome. This patient presented with sudden onset of right-sided hemiparesis and hemilateral sensory disturbance accompanied by a left temporal cluster-like headache and later developed epilepsy during hospitalization, with no other signs suggestive of myopathy, lactate acidosis, or other systemic symptoms. Brain magnetic resonance imaging revealed variable lesions involving multiple cortical and subcortical regions. Furthermore, a negative genetic test obtained from peripheral blood delayed the diagnosis of mitochondrial disease, which was eventually established through second-generation DNA sequencing using biopsied muscle. CONCLUSION Based on this report, we suggest that clinicians pursue proper genetic testing for patients when the clinical phenotype is suggestive of mitochondrial diseases. 展开更多
关键词 MITOCHONDRIAL disease Stroke-like EPISODE Magnetic resonance diagnosis Case report
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谐振式液体密度计的设计与实现 预览
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作者 冯帅 杜海龙 王海丽 《传感器与微系统》 CSCD 2019年第10期92-95,共4页
针对航空蓄电池电解液密度测量需求,设计了一台数字式液体密度计。系统由取样、振动、信号处理、操作显示四部分组成。其中,取样模块利用蠕动泵完成待测液体的自动进样;振动模块采用电磁激振方式实现谐振;信号处理模块以单片机为核心,... 针对航空蓄电池电解液密度测量需求,设计了一台数字式液体密度计。系统由取样、振动、信号处理、操作显示四部分组成。其中,取样模块利用蠕动泵完成待测液体的自动进样;振动模块采用电磁激振方式实现谐振;信号处理模块以单片机为核心,自动调节激振信号的幅值和相位,获得谐振频率并计算液体密度;操作显示模块通过触摸屏实现人机交互和结果显示。实验数据表明:系统关键器件参数选择合理,在量程设计范围内,仪器测量绝对误差最大值为0.002 g/cm~3,能够满足航空蓄电池维护需求。 展开更多
关键词 液体密度 密度计 谐振 U型管
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基于模态追踪的地铁车辆低频横向晃动分析 预览
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作者 陈迪来 沈钢 宗聪聪 《铁道学报》 EI CAS CSCD 北大核心 2019年第10期47-52,共6页
为研究车体低频横向晃动的原因及提高旅客乘坐舒适性,首先依据模糊数学的欧式贴近度准则,有效追踪和分析了车辆各刚体模态随速度变化的情况;其次,基于欧式贴近度定义整个系统所有模态之间的耦合度;最后,以降低车辆系统的耦合度为优化目... 为研究车体低频横向晃动的原因及提高旅客乘坐舒适性,首先依据模糊数学的欧式贴近度准则,有效追踪和分析了车辆各刚体模态随速度变化的情况;其次,基于欧式贴近度定义整个系统所有模态之间的耦合度;最后,以降低车辆系统的耦合度为优化目标,对悬挂参数进行优化。计算结果表明:在某一速度下,当转向架蛇行运动的频率与车体横向振动的固有频率接近时,两者振型极为相似,欧式贴近度接近于1,转向架蛇行运动与车体横向运动发生共振,使车体横向发生低频晃动,此时车辆系统耦合度最大。对车辆悬挂参数优化后,可有效降低系统内的耦合度,减少转向架蛇行运动对车辆横向振动的影响,消除车体低频晃动现象。 展开更多
关键词 蛇行运动 低频晃动 模糊数学 模态追踪 共振 耦合度
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一种适用于S波段的多频微带天线的研究与设计 预览
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作者 池涛 路厚文 《电子元件与材料》 CAS CSCD 北大核心 2019年第9期82-86,共5页
设计了一种工作于S波段的多频缝隙微带天线。以基本矩形双频微带天线为基础,采用同轴馈电,通过在矩形贴片上加载圆形和矩形缝隙改变表面电流分布,实现天线的多频段工作。采用基于有限元方法的电磁仿真软件HFSS 14.0对所设计的多频天线... 设计了一种工作于S波段的多频缝隙微带天线。以基本矩形双频微带天线为基础,采用同轴馈电,通过在矩形贴片上加载圆形和矩形缝隙改变表面电流分布,实现天线的多频段工作。采用基于有限元方法的电磁仿真软件HFSS 14.0对所设计的多频天线进行仿真与优化。仿真分析结果表明,该天线工作在2.04,2.50和2.97 GHz三个工作频段上,回波损耗值分别为-26,-22和-29dB,-10dB阻抗带宽分别为2.01~2.07GHz,2.44~2.55GHz和2.95~2.99GHz,最大增益分别为1.79,3.28和3.9 dB。该多频段微带天线具有体积小、回波损耗低等优点,可用于无线通信系统。 展开更多
关键词 S波段 多频 微带天线 谐振 回波损耗 无线通信
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Imaging biomarkers for the treatment of esophageal cancer 预览
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作者 Koichi Hayano Gaku Ohira +6 位作者 Atsushi Hirata Tomoyoshi Aoyagi Shunsuke Imanishi Toru Tochigi Toshiharu Hanaoka Kiyohiko Shuto Hisahiro Matsubara 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第24期3021-3029,共9页
Esophageal cancer is known as one of the malignant cancers with poor prognosis.To improve the outcome,combined multimodality treatment is attempted.On the other hand,advances in genomics and other“omic”technologies ... Esophageal cancer is known as one of the malignant cancers with poor prognosis.To improve the outcome,combined multimodality treatment is attempted.On the other hand,advances in genomics and other“omic”technologies are paving way to the patient-oriented treatment called“personalized”or“precision”medicine.Recent advancements of imaging techniques such as functional imaging make it possible to use imaging features as biomarker for diagnosis,treatment response,and prognosis in cancer treatment.In this review,we will discuss how we can use imaging derived tumor features as biomarker for the treatment of esophageal cancer. 展开更多
关键词 Esophageal cancer Computed TOMOGRAPHY perfusion Dynamic-contrastenhanced magnetic resonance IMAGING Texture analysis DIFFUSION-WEIGHTED IMAGING POSITRON emission TOMOGRAPHY
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Development and in vitro study of a bi-specific magnetic resonance imaging molecular probe for hepatocellular carcinoma 预览
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作者 Xiao-Hong Ma Shuang Wang +7 位作者 Si-Yun Liu Kun Chen Zhi-Yuan Wu Deng-Feng Li Yong-Tao Mi Long-Bin Hu Zhong-Wei Chen Xin-Ming Zhao 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第24期3030-3043,共14页
BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new... BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new strategies to enhance specificity and help early diagnosis of HCC.However,the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3,which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors<1 cm(MHCC).We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.AIM To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.METHODS A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3(UAG)was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle(USPIO).At the same time,the singly labeled probes of anti-AFP-USPIO(UA)and anti-GPC3-USPIO(UG)and non-targeted USPIO(U)were also prepared for comparison.The physical characterization including morphology(transmission electron microscopy),hydrodynamic size,and zeta potential(dynamic light scattering)was conducted for each of the probes.The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3.First,AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry.Then,the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and in vitro MRI(T2-weighted and T2-map)with a 3.0 Tesla clinical MR scanner.RESULTS Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens co 展开更多
关键词 Hepatocellular carcinoma Molecular IMAGING Magnetic resonance IMAGING Ultra-small SUPERPARAMAGNETIC iron nanoparticles ALPHA-FETOPROTEIN GLYPICAN-3
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Biomarkers vs imaging in the early detection of hepatocellular carcinoma and prognosis 预览
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作者 Lavinia Alice Balaceanu 《世界临床病例杂志》 2019年第12期1367-1382,共16页
Hepatocellular carcinoma (HCC) is the 5th most frequently diagnosed cancer in the world, according to the World Health Organization. The incidence of HCC is between 3/100000 and 78.1/100000, with a high incidence repo... Hepatocellular carcinoma (HCC) is the 5th most frequently diagnosed cancer in the world, according to the World Health Organization. The incidence of HCC is between 3/100000 and 78.1/100000, with a high incidence reported in areas with viral hepatitis B and hepatitis C, thus affecting Asia and Africa predominantly. Several international clinical guidelines address HCC diagnosis and are structured according to the geographical area involved. All of these clinical guidelines, however, share a foundation of diagnosis by ultrasound surveillance and contrast imaging techniques, particularly computed tomography, magnetic resonance imaging, and sometimes contrast-enhanced ultrasound. The primary objective of this review was to systematically summarize the recent published studies on the clinical utility of serum biomarkers in the early diagnosis of HCC and for the prognosis of this disease. 展开更多
关键词 HEPATOCELLULAR carcinoma Biomarkers IMAGING ULTRASONOGRAPHY COMPUTED TOMOGRAPHY Magnetic resonance IMAGING
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Numerical investigation of edge configurations on piston-modal resonance in a moonpool induced by heaving excitations 预览
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作者 Sheng-chao Jiang Pei-wen Cong +1 位作者 Lei Sun Chang-feng Liu 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第4期682-699,共18页
The renormalization group (RNG) turbulent model is used to investigate the fluid resonance in a moonpool formed by two identical rectangular hulls under synchronous heaving excitation (e.g., a catamaran or dual pontoo... The renormalization group (RNG) turbulent model is used to investigate the fluid resonance in a moonpool formed by two identical rectangular hulls under synchronous heaving excitation (e.g., a catamaran or dual pontoon). The numerical model is validated against the available experimental data, and accurate numerical solutions are obtained. The present study focuses on the amplitude of the moving hulls and the edge configuration of the moonpool entrance, as well as their influences on the piston-modal resonant wave in the moonpool. The dependence of the resonant wave amplitude in the moonpool on the heaving amplitude, the characteristic moonpool dimensions and the local velocity magnitude is derived based on a theoretical analysis, and the results are in good agreement with the RNG turbulent solutions. Five different edge profiles are considered, including two convex edges, two concave edges (both with various dimensions), and a sharp edge. Numerical examinations show that the edge configuration has a significant influence on the piston-modal resonant responses, a larger opening size leading to a higher resonant frequency and a larger resonant wave amplitude in the moonpool. Various flow patterns of the piston-modal resonance in the vicinity of the moonpool entrance are also identified, mainly depending on the edge profile. More intensive turbulent and vortical flows give rise to more significant dissipation, accounting for the smaller relative wave amplitude in the moonpool. With the increase of the heaving amplitude, the relative piston-modal resonant amplitude is decreased in an approximate power function. Within the scope of this work, the numerical investigations show that the piston-modal resonant frequency is hardly affected by the heaving amplitude. 展开更多
关键词 Moonpool wave RESONANCE comer shape RENORMALIZATION group (RNG) turbulent model heaving motion
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