Neurobiological Mechanisms for Semantic Feature Extraction and Conceptual Flexibility

Signs and symbols relate to concepts and can be used to speak about objects, actions, and their features. Theories of semantic grounding address the question how the latter two, concepts and real-world entities, come into play and interlink in symbol learning. Here, a neurobiological model is used to spell out concrete mechanisms of symbol grounding, which implicate the “association” of information about sign and referents and, at the same time, the extraction of semantic features and the formation of abstract representations best described as conjoined and disjoined feature sets that may or may not have a real-life equivalent. The mechanistic semantic circuits carrying these feature sets are not static conceptual entries, but exhibit rich activation dynamics related to memory, prediction, and contextual modulation. Four key issues in specifying these activation dynamics will be highlighted: (a) the inner structure of semantic circuits, (b) mechanisms of semantic priming, (c) task specificity in semantic activation, and (d) context-dependent semantic circuit activation in the processing of referential, existential, and universal statements. These linguistic-semantic examples show that specific mechanisms are required to account for context-dependent semantic function or conceptual “flexibility.” Static context-independent concepts as such are insufficient to account for these different semantic functions. Whereas abstract amodal models of concepts did so far not spell out concrete mechanisms for context-dependent semantic function, neuronal assembly mechanisms offer a workable perspective.     

Exploration of the volumetric composition of human lung cancer nodules in correlated histopathology and computed tomography

Gaining a complete and comprehensive understanding of lung cancer nodule histological compositions and how these tissues are represented in radiological data is important not only for expanding the current knowledge base of cancer growth and development but also has potential implications for classification standards, radiological diagnosis methods and for the evaluation of treatment response. In this study we generate large scale histological segmentations of the cancerous and non-cancerous tissues within resected lung nodules. We have implemented a processing pipeline which allows for the direct correlation between histological data and spatially corresponding computed tomography data. Utilizing these correlated datasets we evaluated the statistical separation between Hounsfield Unit (HU) histogram values for each tissue type. The findings of this study revealed that lung cancer nodules contain a complex intermixing of cellular tissue types and that trends exist in the relationship between these tissue types. It was found that the mean Hounsfield Unit values for isolated lung cancer nodules imaged with computed tomography, had statistically significantly different values for non-solid bronchoalveolar carcinoma, solid cancerous tumor, blood, and inactive fibrotic stromal tissue.     

Correlation between the Elecsys HBsAg II assay and the Architect assay for the quantification of hepatitis B surface antigen (HBsAg) in the serum

BackgroundHepatitis B surface antigen (HBsAg) clearance during chronic hepatitis B (CHB) infection is associated with improved long-term clinical outcome, so is considered an important therapeutic goal in CHB. Studies have shown that serum HBsAg quantification during, and at end of, treatment may predict long-term HBsAg loss.ObjectivesPerformance comparison of the qualitative Elecsys HBsAg II assay using a quantitative research protocol and an established quantitative HBsAg assay.Study designA dilution algorithm was developed for the Elecsys HBsAg II assay to allow quantification of HBsAg levels; this was used to measure HBsAg levels in a range of samples including sera from patients infected with different HBV genotypes, HBV mutants, and longitudinal samples from patients undergoing antiviral treatment. Results were compared with those from the quantitative Architect HBsAg assay.ResultsThere was significant overall correlation between Elecsys and Architect assays (correlation coefficient [r] = 0.97; p < 0.001). HBsAg levels measured with both assays correlated well in all phases of infection (r = 0.80–0.96), across all genotypes tested (HBV genotype A, r = 0.89; HBV genotype D, r = 0.97), and in samples with lamivudine-resistant mutations (r = 0.94). Bland–Altman analysis showed only minor discordance between assays in different phases of chronic HBV-infection (3.8–5.1%). This strong correlation was also present for sera with lower HBsAg concentrations. On-treatment HBsAg levels were similar when measured with either assay.ConclusionsUsing a simple dilution algorithm, the quantitative Elecsys HBsAg II assay reliably determined serum HBsAg levels in a wide range of samples, and showed very high correlation with the Architect HBsAg assay.     

利用光学相干断层图像平均灰度值定量研究牛恒牙早期人工脱矿

目的 研究经酸蚀脱矿后牛恒牙光学相干断层图像平均灰度值的变化,探讨平均灰度值作为一个参数指标定量检测牛恒牙早期脱矿的可行性.方法 以正常离体牛恒牙为样本,采用凝胶酸蚀法制备人工脱矿模型;用光学相干断层摄影术对人工脱矿模型扫描成像,利用Matlab软件计算不同酸蚀时间脱矿区牙体层110 μm范围内的平均灰度值.将测得图像灰度和归一化后图像灰度,分别进行单因素方差分析.结果 牙体表层110 μm范围内不同时间酸蚀脱矿区的平均灰度值从大到小依次为30 min酸蚀脱矿区、1O min酸蚀脱矿区、0 min酸蚀脱矿区,图像灰度归一化后做单因素方差分析,P＜0.05.结论 牙体表层110 μm范围内不同酸蚀时间脱矿区平均灰度值差异有统计学意义,并随脱矿时间增加而增大,即平均灰度值可以用于光学相干断层摄影术定量检测牙齿的早期脱矿.光学相干断层图像灰度归一化使得不同酸蚀脱矿区的平均灰度值更有可比性,减小了由于样本之间差异引起的误差,提高了平均灰度值作为参数指标定量检测牙齿早期脱矿的可靠性.     

量化考核在护理管理中的应用

目的探讨量化考核在病区管理中的应用效果。方法根据病区护理人员特点和病人对护理服务的需求制定量化考核标准,通过护士长、质量管理小组长、科室护士的三级考核结构每月进行考核、汇总。结果2008年与2007年相比较,护理绩效考核评分与护理服务满意度差别均有统计学意义（P〈0．05）,说明在病区实施量化考核管理后比实施前护理质量及护理人员的业务素质均有提高。结论通过在病区实施量化考核管理,提高了护理质量和病人的满意度,并在护理队伍中形成了勤于学习、努力进取的良好风气。     

西安市碑林区宾馆旅店实施公共场所卫生监督量化分级管理效果评估

[目的]对西安市碑林区宾馆旅店实施公共场所卫生监督量化分级管理效果进行评估。[方法]对本区所有宾馆旅店进行摸底调查、通过发放卫生许可证时和日常监督分别进行现场量化打分,填写量化评分表。[结果]量化后D级单位所占比例明显下降,A、B级单位比例明显上升,量化后一些检查指标合格率得到较大提高。[结论]实施公共场所卫生监督量化分级管理后,旅店在软件管理和硬件设施、规范操作上较以前有了大幅提高,但小型旅店应作为监督管理的重点对象。     

HPLC方法同时测定九里香中的三个主要成分(英文)

九里香是传统中药九里香属植物的两个基原植物之一。本研究建立了一种快速、有效的HPLC分析方法,能够实现在20分钟内同时测定九里香中两个香豆素类化合物,海南九里香内酯(1)和橙皮内酯(2),以及一个多甲氧基黄酮类化合物,3,5,6,7,3′,4′,5′-七甲氧基黄酮(3)。色谱条件为采用DIKMA Spursil C18色谱柱,乙腈–水(50:50,v/v)等度洗脱,柱温25 oC,流速1 m L/min,320 nm检测。三个主要成分分离度良好,在测试范围内线性关系良好,r>0.999;精密度、重复性、稳定性良好;平均加样回收率在100.52%–101.97%之间,RSD值小于2%。采用该方法对20批不同产地的九里香药材进行含量测定,三个主要成分的含量和在1.55–7.45 mg/g。此外,还对九里香不同部位如主茎、侧枝、嫩枝和叶,及不同采收期的药材进行了测定。结果表明,三个主要成分在嫩枝及叶中的含量明显高于主茎或侧枝中,所以药典规定以九里香的叶及嫩枝作为药用部位是合理的;六月或十月为最佳采收期;产自广东茂名市、深圳市、广西南宁市、天峨市和福建漳州市的九里香中主要活性成分的含量高于其他产地。该方法具有高效、简便的特点,可用于九里香药材及其相关产品的质量控制。     

面部对称性的量化研究和临床应用

目的探索面部器官的对称性和形态学特征,为面部的修复重建、美容整形手术提供依据。方法随机选择50例正常青年女性,采用计算机辅助的照片测量法,测量面部的对称距离及角度,观察测量数据的差异和变化。然后选出10例,用计算机制作其侧面部合成图,并和原图进行评分比较。两次实验均用SAS软件进行统计分析。结果内外眦连线和水平线的夹角、眉头眉峰连线和水平线的夹角、鼻翼点到口角点间距、口角点到下颌角点间距,以及下颌角点到软组织颏下点间距,在左右两侧面部的测量值有统计学差异。左右两侧面部合成图的评分分值明显小于被测者原先照片的评分值。结论中下面部组织的不对称性较为明显。面部的绝对对称是不存在的。对称性的概念不能独立而单一地应用于人体美学中。面部对称形态特征的标准化研究和范围界定还有待进一步的探索。     

Four-dimensional flow magnetic resonance imaging in cirrhosis

Since its introduction in the 1970’s, magnetic resonance imaging (MRI) has become a standard imaging modality. With its broad and standardized application, it is firmly established in the clinical routine and an essential element in cardiovascular and abdominal imaging. In addition to sonography and computer tomography, MRI is a valuable tool for diagnosing cardiovascular and abdominal diseases, for determining disease severity, and for assessing therapeutic success. MRI techniques have improved over the last few decades, revealing not just morphologic information, but functional information about perfusion, diffusion and hemodynamics as well. Four-dimensional (4D) flow MRI, a time-resolved phase contrast-MRI with three-dimensional (3D) anatomic coverage and velocity encoding along all three flow directions has been used to comprehensively assess complex cardiovascular hemodynamics in multiple regions of the body. The technique enables visualization of 3D blood flow patterns and retrospective quantification of blood flow parameters in a region of interest. Over the last few years, 4D flow MRI has been increasingly performed in the abdominal region. By applying different acceleration techniques, taking 4D flow MRI measurements has dropped to a reasonable scanning time of 8 to 12 min. These new developments have encouraged a growing number of patient studies in the literature validating the technique’s potential for enhanced evaluation of blood flow parameters within the liver’s complex vascular system. The purpose of this review article is to broaden our understanding of 4D flow MRI for the assessment of liver hemodynamics by providing insights into acquisition, data analysis, visualization and quantification. Furthermore, in this article we highlight its development, focussing on the clinical application of the technique.