HRTEM observation of misfit dislocations at non-faceted Al–Pb interfaces

Al–Pb samples containing 1?at.%?Pb were produced by high-energy ball milling and investigated by high-resolution transmission electron microscopy. The Pb inclusions embedded in an Al matrix exhibit a non-faceted, curved morphology. Dislocations have been found to accommodate the misfit of about 22% at the Al–Pb interfaces. Burgers circuits, drawn around these misfit dislocations, exhibit closing failures of the type a₀ /4〈211〉.     

索拉非尼治疗晚期肾癌的临床研究

探讨索拉非尼治疗晚期转移性肾癌的疗效和毒副反应.我院门诊收治的晚期肾癌患者共70例,服用索拉非尼,每个月进行1次疗效评价,每2个月进行一次影像学评价.70例患者中完全缓解(CR)0例、部分缓解(PR)2例、稳定(SD)40例、疾病进展(PD)1例,死亡27例.中位无进展生存期(PFS) 18(6～65)个月,中位总生存期(OS) 12个月.1年、2年、3年生存率分别为83.7％、40.9％、18.7％.有轻中度的不良反应,因此,索拉非尼对晚期肾癌有良好的治疗效果,并且药物副反应轻.     

Cortical Cell Assemblies: A Possible Mechanism for Motor Programs

The concept of a motor program has been used to interpret a diverse range of empirical findings related to preparation and initiation of voluntary movement. In the absence of an underlying mechanism, its explanatory power has been limited to that of an analogy with running a stored computer program. We argue that the theory of cortical cell assemblies suggests a possible neural mechanism for motor programming. According to this view, a motor program may be conceptualized as a cell assembly, which is stored in the form of strengthened synaptic connections between cortical pyramidal neurons. These connections determine which combinations of corticospinal neurons are activated when the cell assembly is ignited. The dynamics of cell assembly ignition are considered in relation to the problem of serial order. These considerations lead to a plausible neural mechanism for the programming of movements and movement sequences that is compatible with the effects of precue information and sequence length on reaction times. Anatomical and physiological guidelines for future quantitative models of cortical cell assemblies are suggested. By taking into account the parallel, re-entrant loops between the cerebral cortex and basal ganglia, the theory of cortical cell assemblies suggests a mechanism for motor plans that involve longer sequences. The suggested model is compared with other existing neural network models for motor programming.     

Executive function performance on the children's kitchen task assessment with children with sickle cell disease and matched controls

Objective: The aim of this study was to compare executive function abilities of 8- to 12-year-old children with sickle cell disease (SCD) with a matched control sample. The measures included the parent and teacher Behavior Rating Inventory of Executive Function (BRIEF); the Delis-Kaplan Executive Function System (D-KEFS), Free Sorting Test and Color Word Interference Test; and the Children's Kitchen Task Assessment (CKTA), a new performance measure. Methods: Twenty-two children with SCD were recruited from one hematology clinic and 22 community children, matched on characteristics of age, gender, and race, were selected from a larger sample of controls for comparison. Parents and teachers completed rating scales. Results:As hypothesized, children with SCD scored significantly lower than matched controls on Digit Span Forward; on 5 of the 9 D-KFES Color Word Interference and Sorting tasks; on CKTA organization, initiation, and task completion; and on the BRIEF's parent and teacher Metacognitive Index (MI) and Global Executive Composite (GEC) scores. Conclusion:Cognitive and performance evaluations indicate lower executive function among children with SCD. Results substantiate the need for evaluative triangulation for children with SCD: Neurocognitive testing supported by performance testing, and adult reflection of a child's daily performance compared to other children. These elements will provide rich data to create educational support for children with SCD who have frequent hospitalizations, school absences, and the potential presence of cerebral vascular accident symptomology.     

Neurocognitive Sequelae of Pediatric Sickle Cell Disease: A Review of the Literature

This literature review summarizes all studies relating neuropsychological performance to neuroimaging findings in pediatric sickle cell disease (N=28; published 1991–2005). Although inconsistencies exist within and across domains, deficits in intelligence (IQ), attention and executive functions, memory, language, visuomotor abilities, and academic achievement have been identified. Overall neurocognitive compromise was revealed to be related to the level of neurological injury and the location of silent infarct. Attentional and executive dysfunction is prevalent and related to frontal lobe abnormalities.     

Semantic embodiment,disembodiment or misembodiment? In search of meaning in modules and neuron circuits

“Embodied” proposals claim that the meaning of at least some words, concepts and constructions is grounded in knowledge about actions and objects. An alternative “disembodied” position locates semantics in a symbolic system functionally detached from sensorimotor modules. This latter view is not tenable theoretically and has been empirically falsified by neuroscience research. A minimally-embodied approach now claims that action–perception systems may “color”, but not represent, meaning; however, such minimal embodiment (misembodiment?) still fails to explain why action and perception systems exert causal effects on the processing of symbols from specific semantic classes. Action perception theory (APT) offers neurobiological mechanisms for “embodied” referential, affective and action semantics along with “disembodied” mechanisms of semantic abstraction, generalization and symbol combination, which draw upon multimodal brain systems. In this sense, APT suggests integrative-neuromechanistic explanations of why both sensorimotor and multimodal areas of the human brain differentially contribute to specific facets of meaning and concepts.     

THE GENETIC RECOMBINATION OF SCIENCE AND RELIGION

The estrangement between genetic scientists and theologians originating in the 1960s is reflected in novel combinations of human thought (subject) and genes (investigational object), paralleling each other through the universal process known in chaos theory as self‐similarity. The clash and recombination of genes and knowledge captures what Philip Hefner refers to as irony, one of four voices he suggests transmit the knowledge and arguments of the religion‐and‐science debate. When viewed along a tangent connecting irony to leadership, journal dissemination, and the activities of the “public intellectual” and the public at large, the sequence of voices is shown to resemble the passage of genetic information from DNA to mRNA, tRNA, and protein, and from cell nucleus to surrounding environment. In this light, Hefner's inquiry into the voices of Zygon is bound up with the very subject matter Zygon covers.     

外科手术在ⅢA期非小细胞肺癌治疗中的作用

ⅢA期非小细胞肺癌治疗方式存在争议,对于N1期患者,外科手术被广泛接受,对于N2期患者,国内外存在一定的分歧。对于N2期患者,外科手术治疗的效果主要取决于纵隔淋巴结转移情况,微灶转移和单站淋巴结转移患者,外科手术治疗效果比较满意,多站淋巴结转移患者外科手术治疗效果较差,而是需要做行根治性的放化疗。     

“三腿一平台”组成的“基因打靶”——评介2007年度诺贝尔医学奖

2007年度诺贝尔医学奖项目——基因打靶,由三腿和一个平台所构成。三条腿分别是转基因学、同源重组和胚胎干细胞,一个平台指的是基因敲除。除了评价这些组成部分以外,还对推迟评奖进行了质疑。     

小儿肾脏替代疗法发展方向的思考

慢性肾功能衰竭目前主要依靠透析或肾移植替代疗法来延长生命,但二者并未彻底解决问题并且代价昂贵.体外干细胞研究的兴起,为解决慢性肾功能衰竭的治疗带来了一丝曙光,但获得成功恐怕还需要一个相当长的时间.只有契合了整体辩证统一原则的再生医学,通过在肾脏原位重建生理环境,激发机体本身潜能,使肾脏修复到自然的完美状态,才能实现与人体生命一体化的有机结合,才是小儿肾脏替代疗法中有光明前景的发展方向.