Transcranial magnetic stimulation

We investigated the effects of unilateral cold-water vestibular stimulation on healthy subjects' performance in two cognitive tasks known to be differentially mediated by the two cerebral hemispheres. In a first experiment (right-hemisphere task), subjects memorized object-location associations while being stimulated with cold water in the left ear or right ear or not at all (control group). In the second experiment (left-hemisphere task), subjects memorized a list of sequentially presented function words while being stimulated in the same manner as the subjects in the first experiment. A recall phase followed each encoding phase. In the first experiment, subjects who had been stimulated in the left ear recalled the object locations significantly faster than subjects who had been stimulated in the right ear and those in the control group. The second experiment yielded the reverse pattern: correct word recognition was faster for subjects who had been stimulated in the right ear than for subjects stimulated in the left ear and those of the control group. We suggest that unilateral caloric stimulation leads to a selective activation of contralateral cerebral structures and speeds up cognitive processes mediated by these structures. These results are discussed with respect to findings in neglect patients and functional-imaging studies in healthy subjects.     

基于一测多评多组分定量质控联合主成分分析、正交偏最小二乘法-判别分析及熵权逼近理想解排序法的盐沙苑子饮片综合质量评价

目的 建立一测多评（quantitative analysis of multicomponents by single-marker,QAMS）法同时检测盐沙苑子饮片中杨梅素、扁蓄苷、杨梅素-3-O-β-D-葡萄糖苷、毛蕊异黄酮葡萄糖苷、西伯利亚落叶松黄酮、沙苑子苷B、沙苑子苷A、毛蕊异黄酮、芒柄花素、鼠李柠檬素、豆甾醇、胡萝卜苷、β-谷甾醇含量的方法,并采用主成分分析法（principal component analysis,PCA）、正交偏最小二乘法-判别分析（orthogonal partial least squares-discriminant analysis,OPLS-DA）法及熵权逼近理想解排序（entropy weight-technique for order preference by similarity to ideal solution,EW-TOPSIS）法对其质量进行评价。方法 采用Lichrospher C18色谱柱;乙腈-0.2%磷酸水溶液为流动相梯度洗脱。以沙苑子苷A为内参物,建立内参物与其他12个待测成分的相对校正因子（relative co...     

Relationship between anterior fontanelle pressure measurements and clinical signs in infantile hydrocephalus

The treatment of choice in progressive hydrocephalus is drainage of cerebrospinal fluid in order to reduce elevated intracranial pressure (ICP). Defining the right moment for surgical intervention, however, in a hydrocephalic infant on the basis of clinical signs alone can be a difficult task. Clinical signs of raised ICP are known to be unreliable and sometimes even misleading. In the present study, the relationship between long-term anterior fontanelle pressure (AFP) measurements and clinical signs was investigated in 37 infants with hydrocephalus. The decision as to whether to operate or not was based on clinical signs alone; AFP values were not taken into account. There was an overall difference between the non-operated group and the preoperative measurements in the operated group, and also between the preoperative and the postoperative measurements in the latter, in regard to both AFP measurements and clinical signs. Almost all preoperative AFP values were increased. The direct correlation () between most individual clinical signs and AFP levels, however, was low (=0.15–0.41). The clinical sign tense fontanelle showed the best correlation with the AFP levels (=0.75). Furthermore, using logistic regression analysis, no combination of clinical signs could be found which reliably predicted the AFP. The relationship between the AFP pressure variables and clinical signs was also examined. The pathological A-waves occurred only in the presence of raised (baseline) AFP, a situation in which considerably more frequent B-waves were observed as well. It was concluded that clinical signs of raised ICP in infantile hydrocephalus are not very reliable and AFP monitoring can therefore provide valuable information on intracranial dynamics in patients with dubious neurological manifestations of progressive hydrocephalus.     

相似系数法在川贝母群落分类中的应用研究

目的　探讨数值分类方法应用于川贝母分布群落类型的划分。方法　以群落相似系数百分率划分川贝母分布的群落类型。结论　应用相似系数法可将川贝母野生抚育的适宜群落划定为窄叶鲜卑花灌丛、理塘杜鹃灌丛、硬叶柳灌丛、金露梅 +绣线菊灌丛、香柏灌丛、珠芽蓼 +圆穗蓼草甸等 6种类型     

不同厂家生产的盐酸曲马多缓释片整片与半片的三维释放特性考察

目的:对不同厂家(A、B、C)的盐酸曲马多缓释片的整片与半片进行pH-时间-释放度考察,探讨整片与半片体外释放机制的差异.方法:转篮法,用紫外分光光度法检测,描绘其三维释放图像,将释放数据用相似因子法、Peppas方程进行分析.结果:在同一pH条件下,A、C的整片与半片释放曲线不相似,释放机制也不相同;B的整片与半片释放曲线相似,释放机制相同.结论:不同厂家盐酸曲马多缓释片整片与半片的体外释放不尽相同.     

Correcting waveform bias using principal component analysis: Applications in multicentre motion analysis studies

Multicentre studies are rare in three dimensional motion analyses due to challenges associated with combining waveform data from different centres. Principal component analysis (PCA) is a statistical technique that can be used to quantify variability in waveform data and identify group differences. A correction technique based on PCA is proposed that can be used in post processing to remove nuisance variation introduced by the differences between centres. Using this technique, the waveform bias that exists between the two datasets is corrected such that the means agree. No information is lost in the individual datasets, but the overall variability in the combined data is reduced. The correction is demonstrated on gait kinematics with synthesized crosstalk and on gait data from knee arthroplasty patients collected in two centres. The induced crosstalk was successfully removed from the knee joint angle data. In the second example, the removal of the nuisance variation due to the multicentre data collection allowed significant differences in implant type to be identified. This PCA-based technique can be used to correct for differences between waveform datasets in post processing and has the potential to enable multicentre motion analysis studies.     

locStra: Fast analysis of regional/global stratification in whole‐genome sequencing studies

locStra is an ‐package for the analysis of regional and global population stratification in whole‐genome sequencing (WGS) studies, where regional stratification refers to the substructure defined by the loci in a particular region on the genome. Population substructure can be assessed based on the genetic covariance matrix, the genomic relationship matrix, and the unweighted/weighted genetic Jaccard similarity matrix. Using a sliding window approach, the regional similarity matrices are compared with the global ones, based on user‐defined window sizes and metrics, for example, the correlation between regional and global eigenvectors. An algorithm for the specification of the window size is provided. As the implementation fully exploits sparse matrix algebra and is written in C++, the analysis is highly efficient. Even on single cores, for realistic study sizes (several thousand subjects, several million rare variants per subject), the runtime for the genome‐wide computation of all regional similarity matrices does typically not exceed one hour, enabling an unprecedented investigation of regional stratification across the entire genome. The package is applied to three WGS studies, illustrating the varying patterns of regional substructure across the genome and its beneficial effects on association testing.     

Identification of 4‐aryl‐1H‐pyrrole[2,3‐b]pyridine derivatives for the development of new B‐Raf inhibitors

During the last years, a significant interest in the identification of new classes of B‐Raf inhibitors has emerged. In this study, which was conceived within an effort that culminated in the recent report of the first dual inhibitors of B‐Raf and Hsp90, we describe the identification of four compounds based on 4‐aryl‐1H‐pyrrole[2,3‐b]pyridine scaffold as interesting starting points for the development of new B‐Raf inhibitors. Structure–activity relationships and predicted binding modes are discussed. Moreover, the novelty of the newly identified structures with respect to currently known B‐Raf inhibitors was assessed through a ligand‐based dissimilarity assessment. Finally, structural modifications with the potential ability to improve the activity toward B‐Raf are put forward.     

Automated total kidney volume measurements in pre-clinical magnetic resonance imaging for resourcing imaging data,annotations, and source code

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Validation of a semi‐automatic co‐registration of MRI scans in patients with brain tumors during treatment follow‐up

There is an expanding research interest in high‐grade gliomas because of their significant population burden and poor survival despite the extensive standard multimodal treatment. One of the obstacles is the lack of individualized monitoring of tumor characteristics and treatment response before, during and after treatment. We have developed a two‐stage semi‐automatic method to co‐register MRI scans at different time points before and after surgical and adjuvant treatment of high‐grade gliomas. This two‐stage co‐registration includes a linear co‐registration of the semi‐automatically derived mask of the preoperative contrast‐enhancing area or postoperative resection cavity, brain contour and ventricles between different time points. The resulting transformation matrix was then applied in a non‐linear manner to co‐register conventional contrast‐enhanced T₁‐weighted images. Targeted registration errors were calculated and compared with linear and non‐linear co‐registered images. Targeted registration errors were smaller for the semi‐automatic non‐linear co‐registration compared with both the non‐linear and linear co‐registered images. This was further visualized using a three‐dimensional structural similarity method. The semi‐automatic non‐linear co‐registration allowed for optimal correction of the variable brain shift at different time points as evaluated by the minimal targeted registration error. This proposed method allows for the accurate evaluation of the treatment response, essential for the growing research area of brain tumor imaging and treatment response evaluation in large sets of patients. Copyright © 2016 John Wiley & Sons, Ltd.