Neural substrates of cognitive skill learning in Parkinson's disease

While cognitive skill learning is normally acquired implicitly through frontostriatal circuitry in healthy individuals, neuroimaging studies suggest that patients with Parkinson's disease (PD) do so by activating alternate, intact brain areas associated with explicit memory processing. To further test this hypothesis, 10 patients with PD and 12 healthy controls were tested on a modified, learning version of the Tower of London task while undergoing positron emission tomography at four different time points over the course of learning. Despite having less accurate problem solving abilities than controls, PD patients were able to acquire the skill learning task. However, as compared to controls, they maintained higher levels of cerebral blood flow activity in the dorsolateral prefrontal cortex and hippocampus and showed an increase in activity in the frontopolar cortex and posterior cingulate over the course of learning. These findings reflect a shift to the explicit memory system in PD patients, enabling them to learn this cognitive skill, which is normally acquired by control subjects using implicit learning strategies and frontostriatal circuitry.     

大动脉炎的影像学诊断比较探讨

探讨大动脉炎的多层螺旋CT血管成像表现及其临床应用价值。回顾分析大动脉炎的多层螺旋CT血管成像表现并结合大量文献进行分析讨论。3例大动脉炎患者血管成像表现为动脉管腔狭窄、扩张及管壁增厚。多层螺旋CT血管成像可同时显示大动脉炎的管壁改变和管腔情况,对大动脉炎早期诊断、治疗方法选择有重要意义。     

肝脾CT值分析在非酒精性脂肪肝诊断中的应用

探讨肝脾CT值分析在非酒精性脂肪肝中诊断及严重程度的关系。对163例临床明确诊断的非酒精性脂肪肝患者,分别根据肝脏cT值、肝脾CT值比值及肝脾CT值差值进行分组。结果三种评价方法对重度非酒精性脂肪肝均有较高的灵敏度及特异度,轻度非酒精性脂肪肝样本中出现28例肝脾CT比值〉1,肝脾值差值与肝脾CT值比值在对脂肪肝严重程度...     

The Contribution of Neuroimaging to the Study of Language and Aphasia

New structural and functional imaging methods continue to be developed at a rapid pace. In the last 25 years, advanced imaging techniques have provided insights into how language is represented and processed in the brain and how it can be disrupted by damage to, or dysfunction of, various parts of the brain. Imaging studies have also yielded new information regarding how individuals recover language after stroke. We briefly review the strengths and weaknesses of the various radiological methods currently used to study language and aphasia.     

肺微小浸润腺癌及浸润前病变HRCT影像特征

为总结肺微小浸润腺癌(MIA)、原位腺癌(AIS)及不典型腺瘤样增生(AAH)结节的HRCT影像特征,回顾性收集43例术前2周内行HRCT检查、经胸腔镜切除、组织病理学证实的50个肺结节,分析结节大小、成分及内部特征.结果显示所有AAH表现为纯磨玻璃结节(pGGN),且≤1.0cm,空气支气管征未见,空泡征少见;86％AIS表现为pGGN,71％的AIS≤1.0cm,且空泡征常见(相对于AAH);95％的MIA表现为混合磨玻璃结节(mGGN),其余为实性结节,90％的MIA＞1.0cm,空气支气管征常见(相对于AIS).因此结节的大小、成分、空泡征及空气支气管征在一定程度上有助于MIA、AIS及AAH的鉴别.     

Observation using synchrotron X-ray diffraction of the crystallographic evolution of α-titanium after oxygen diffusion

In this study, the effect of oxygen diffusion on the crystallographic evolution of α-titanium has been studied using synchrotron X-ray diffraction. Measurements were carried out directly on sample cross-sections that were directly pre-oxidized at high temperature. Changes in hardness, oxygen content and lattice parameters after oxidation were determined by coupling microhardness measurements and electron probe microanalyzer results.     

Unusual stress behaviour of CeO2-doped diamond-like carbon nanofilms

CeO₂-doped diamond-like carbon (DLC) films with thicknesses of 180–200 nm were deposited by unbalanced magnetron sputtering. When the CeO₂ concentration is in the range 5–8%, the residual compressive stress of the deposited films is reduced by 90%, e.g. from about 4.1 GPa to 0.5 GPa, whereas their adhesion strength increases. These effects are attributed to the dissolution of CeO₂ within the DLC amorphous matrix and a widening interface between the DLC film and the Si substrate, respectively.     

X线伤害:先天性心脏病介入治疗知情同意的盲点

随着先天性心脏病介入治疗快速发展,受X线照射的患儿日益增多。而X线照射的危害并未受到临床医生的重视,家属也没有充分的知情同意。     

Central executive function in mild cognitive impairment: a PET activation study

Using positron emission tomography (PET), we explored the neural correlates of an executive function, dual tasking, in patients with amnestic mild cognitive impairment (aMCI) and in elderly controls. The experiment employed simple auditory and visual tasks that were presented both in isolation and simultaneously to create a task condition requiring enhanced attentional control. Behaviorally, both groups performed well, albeit the patients made more errors on the visual task. The PET analysis focused at prefrontal regions where group differences in task-related activation patterns were expected. During dual task performance, the patients showed attenuated activity in the left inferior frontal region when compared to the controls. This suggests abnormalities in the neural processes underlying attentional control in aMCI.