小鼠黑色素瘤移植瘤中血管生成拟态的时空变化

目的:利用小鼠移植瘤模型动态观察血管生成拟态的时空变化.方法:采用B16黑色素瘤细胞和C57小鼠制作小鼠恶性黑色素移植瘤动物模型,成瘤后根据随机数字表每天随机抽取一只小鼠处死,共12d,获得肿瘤样本114例.常规HE染色和CD31、PAS染色.显微镜下分别计数肿瘤组织中央区和外周区的高倍视野(×400)下血管生成拟态以及内皮依赖性血管.结果:在移植瘤形成的第1～8天,肿瘤组织内存在血管生成拟态.第9～12天该结构被内皮依赖性血管替代.肿瘤中央区、外周区血管生成拟态密度均呈现先递增后递减趋势;两个区域内的血管生成拟态密度比较:在第1～6天内肿瘤中央区高于外周区,在第7～8天肿瘤外周区高于中央区.内皮依赖性血管在肿瘤组织的中央区和外周区呈现递减趋势.两个区域内的内皮依赖性血管密度比较:在第1～7天肿瘤中央区内皮依赖性血管密度高于外周区,在第8～12d两个区域内的内皮依赖性血管密度无明显差别.血管生成拟态密度与肿瘤组织的坏死率之间呈密切负相关(r=-0.978,P<0.05);内皮依赖性血管密度与肿瘤组织坏死率之间亦存在负相关(r=-0.230,P<0.05).结论:黑色素瘤移植瘤中血管生成拟态是肿瘤细胞为适应环境而产生的一种暂时性的血液供应方式,与内皮依赖性血管并存于肿瘤组织内.随肿瘤生长变化而与内皮依赖性血管之间存在一定的时空变化规律.     

The successful resolution of armed hostage/barricade events in schools: A qualitative analysis

This article explores the perceptions and reactions of school and law enforcement personnel in the successful resolution of armed hostage and barricade events in schools. A total of 12 individuals from three schools were interviewed to determine (1) their salient roles related to the situations, (2) facilitative systemic conditions, (3) to what they attributed the successful resolution, and (4) their advice to other school professionals. Results suggest that establishment of trusting relationships between school personnel and all students is essential in successfully resolving school hostage and barricade events. In addition, respondents discussed the importance of awareness, training, and communications in resolving such events. Implications for school staff are included, along with limitations and future research directions. © 2007 Wiley Periodicals, Inc.     

Exploring Teachers’ Depressive Symptoms,Interaction Quality,and Children’s Social-Emotional Development in Head Start

Research Findings: This study explored the role Head Start teachers’ (n = 355) depressive symptoms play in their interactions with children and in children’s (n = 2,203) social-emotional development, specifically changes in children’s problem behaviors and social skills as reported by parents and teachers during the preschool year. Results of the multilevel path analyses revealed that children in classrooms with more depressed teachers made significantly fewer gains in social-emotional skills as reported by both teachers and parents. We found no evidence of mediation by the quality of teacher–child interactions. Practice or Policy: These findings have implications for understanding and supporting Head Start teachers’ mental health and potentially improving children’s social-emotional outcomes.     

Refining the Map of the Counselor Development Journey: Response to Rønnestad and Skovholt

In this article, we respond to Rønnestad and Skovholt's reformulated counselor development model itself, then to some of its implications. With respect to the model: (a) although this version is more parsimonious than the original, we show that it could be more so; and (b) because the authors do not discuss determinants of psychotherapy as a career choice, we draw from existing literature to suggest some. With respect to the implications of the work, we note that: (a) trainee anxiety may not be as important as its prominence in their model suggests; (b) Rønnestad and Skovholt's finding that older practitioners turn to alternative sources (e.g., cinema; literature) to learn about human nature may be related to the consistent finding that practitioners are not research consumers; and (c) the importance Rønnestad and Skovholt attach that post-licensure supervision should be given more attention.     

A group randomized controlled trial evaluating parent involvement in whole-school actions to reduce bullying

Parents can significantly affect children's peer relationships, including their involvement in bullying. The authors developed and evaluated ways to enhance parents’ knowledge, self-efficacy, attitudes, and skills related to parent–child communication about bullying. The 3-year Friendly Schools Friendly Families whole-school intervention included a family component, which provided training and resources to support school teams to engage families in awareness-raising and skill-building activities. Over 3,200 parents of the Grade 2, 4, and 6 cohorts were recruited. For the Grade 2 and 4 cohorts at both 10 and 22 months postintervention, the family component increased parents’ self-efficacy to talk about bullying with their children and their frequency of doing so. Grade 4 parents reported more provictim attitudes at 22 months. No differences were found for the Grade 6 cohort. These data suggest a whole-school capacity-building intervention in early and middle childhood can improve the likelihood and frequency of positive parent–child communication about bullying.     

Playing With Ideas: Evaluating the Impact of the Ultimate Block Party,a Collective Experiential Intervention to Enrich Perceptions of Play

Parental attitudes shape play opportunities afforded to children in home, community, and school settings. This study presents evaluation of an intervention designed to enrich parent's conception of play and its relationship with socially valued skills and capacities. On the basis of data from 291 racially and ethnically diverse parents/caregivers of young children (median age between 3 and 6) attending an event in NYC, we find the intervention helped parents conceptualize play in complex ways and altered perceptions of its impact on children's current—but not future—lives. Multivariate analyses reveal the causal pathway for these changes as exposure to multiple play sites, rather than time at the event—a finding with direct implications for exposing parents to developmental science in community settings.     

Sentence context and meaning frequency effects in children's processing of ambiguous words

Nine- and twelve-year-old children named target words which were preceded by sentences ending in words having more than one meaning. Sentences biased the ambiguous word toward its dominant (more frequent) or subordinate (less frequent) meaning. Targets were related to the same meaning as that biased by the sentence, the other meaning, or were unrelated. Targets were presented 0, 300, or 700 ms following the sentence. For both ages, dominant sentences facilitated responses only to the contextually appropriate target. However, subordinate sentences led to facilitation of the appropriate meaning only for the younger group. Older children showed greater facilitation for the inappropriate (but more common) meaning. These results indicate that younger children are more sensitive to the sentence context in which an ambiguous word appears, while the processing of the older children is determined more by the relative frequencies of the words meanings.     

The Relation Between Self-Regulated Learning and Academic Achievement Across Childhood and Adolescence: A Meta-Analysis

This research synthesis explores how academic achievement relates to two main components of self-regulated learning for students in elementary and secondary school. Two meta-analyses integrated previous findings on (1) the defining metacognitive processes of self-regulated learning and (2) students’ use of cognitive strategies. Overall correlations were small (metacognitive processes, r?=?0.20; cognitive strategies, r?=?0.11), but there was systematic variation around both of them. Five moderator analyses were conducted to explain this variation. Average correlations significantly differed based on the specific process or strategy, academic subject, grade level, type of self-regulated learning measure, and type of achievement measure. Follow-up tests explored the nature of these differences and largely support the hypotheses. Theoretical, methodological, and practical implications of these findings are discussed.