801 research outputs found
A Knockout of the Tsg101 Gene Leads to Decreased Expression of ErbB Receptor Tyrosine Kinases and Induction of Autophagy Prior to Cell Death
The Tumor Susceptibility Gene 101 (Tsg101) encodes a multi-domain protein that mediates a variety of molecular and biological processes including the trafficking and lysosomal degradation of cell surface receptors. Conventional and conditional knockout models have demonstrated an essential requirement of this gene for cell cycle progression and cell viability, but the consequences of a complete ablation of Tsg101 on intracellular processes have not been examined to date. In this study, we employed mouse embryonic fibroblasts that carry two Tsg101 conditional knockout alleles to investigate the expression of ErbB receptor tyrosine kinases as well as stress-induced intracellular processes that are known to be associated with a defect in growth and cell survival. The conditional deletion of the Tsg101 gene in this well-controlled experimental model resulted in a significant reduction in the steady-state levels of the EGFR and ErbB2 but a stress-induced elevation in the phosphorylation of mitogen activated protein (MAP) kinases independent of growth factor stimulation. As part of an integrated stress response, Tsg101-deficient cells exhibited extensive remodeling of actin filaments and greatly enlarged lysosomes that were enriched with the autophagy-related protein LC3. The increase in the transcriptional activation and expression of LC3 and its association with Lamp1-positive lysosomes in a PI3K-dependent manner suggest that Tsg101 knockout cells utilize autophagy as a survival mechanism prior to their ultimate death. Collectively, this study shows that a knockout of the Tsg101 gene causes complex intracellular changes associated with stress response and cell death. These multifaceted alterations need to be recognized as they have an impact on defining particular functions for Tsg101 in processes such as signal transduction and lysosomal/endosomal trafficking
Novel transcripts from a distinct promoter that encode the full-length AKT1 in human breast cancer cells
Surface electrons at plasma walls
In this chapter we introduce a microscopic modelling of the surplus electrons
on the plasma wall which complements the classical description of the plasma
sheath. First we introduce a model for the electron surface layer to study the
quasistationary electron distribution and the potential at an unbiased plasma
wall. Then we calculate sticking coefficients and desorption times for electron
trapping in the image states. Finally we study how surplus electrons affect
light scattering and how charge signatures offer the possibility of a novel
charge measurement for dust grains.Comment: To appear in Complex Plasmas: Scientific Challenges and Technological
Opportunities, Editors: M. Bonitz, K. Becker, J. Lopez and H. Thomse
Pregnancy-induced changes in cell-fate in the mammary gland
The protective effect of an early full-term pregnancy is a well established phenomenon; in contrast, the molecular and cell-specific mechanisms that govern parity-specific changes in the mammary gland have not been well described. Recent studies signify a dramatic advance in our understanding of this phenomenon, and indicate a 'cell fate' model for parity-related changes that lead to protection against breast cancer
Southern California Earthquake Center Geologic Vertical Motion Database
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94655/1/ggge1319.pd
The development of study-specific self-efficacy during grammar school.(Zur Entwicklung der studienspezifischen Selbstwirksamkeit in der Oberstufe)
Article is in German.
Even if more and more German adolescents acquire a university entrance qualification, not all of them finally enrol at a university. In particular, the transition from school to university strongly depends on parent’s education. Even with the same marks in school, adolescents from non-academic households are less likely to enrol in universities than adolescents from academic housholds. One important reason is their lower belief to master a university study. This study analyses a specific intervention in grammar school to improve study-specific self- efficacy, the belief in one’s capabilities to master a university study, using a longitudinal design. We apply a difference-in-difference framework and show that programme participation significantly improves the study-specific self-efficacy for puplis from non- academic families but not for those from academic families. Hence, such a programme could reduce social disparities between both groups
Reactive oxygen species initiate luminal but not basal cell death in cultured human mammary alveolar structures: a potential regulator of involution
Post-lactational involution of the mammary gland is initiated within days of weaning. Clearing of cells occurs by apoptosis of the milk-secreting luminal cells in the alveoli and through stromal tissue remodeling to return the gland almost completely to its pre-pregnant state. The pathways that specifically target involution of the luminal cells in the alveoli but not the basal and ductal cells are poorly understood. In this study we show in cultured human mammary alveolar structures that the involution process is initiated by fresh media withdrawal, and is characterized by cellular oxidative stress, expression of activated macrophage marker CD68 and finally complete clearing of the luminal but not basal epithelial layer. This process can be simulated by ectopic addition of reactive oxygen species (ROS) in cultures without media withdrawal. Cells isolated from post-involution alveoli were enriched for the CD49f+ mammary stem cell (MaSC) phenotype and were able to reproduce a complete alveolar structure in subcultures without any significant loss in viability. We propose that the ROS produced by accumulated milk breakdown post-weaning may be the mechanism underlying the selective involution of secretory alveolar luminal cells, and that our culture model represents an useful means to investigate this and other mechanisms further
Effects of Instruction in Morphological Awareness on Literacy Achievement: An Integrative Review
As many studies have now demonstrated that morphological awareness contributes to students' literacy development, there is growing interest in the educational value of instruction in morphological awareness. This review was undertaken to integrate findings of studies that sought to determine whether such instruction contributed to improvement in literacy. Analysis of the 16 studies that met selection criteria is organized around researchers' purpose(s) in studying the relation of morphological awareness instruction to key components of literacy development (i.e., phonology, orthography, word meaning). Results indicate that morphological awareness has the potential to contribute to students' literacy development in all three areas—most notably when it deepens students' understanding of the morphemic structure, spelling, and meaning of written words. However, examination of the design and quality of the studies of instruction in morphological awareness suggests that this is an emerging area of research. Much needs to be done to provide a clearer understanding of how, when, and why morphological awareness instruction contributes to students' literacy development. تزايد الاهتمام بالقيمة التعليمية للتدريس في مجال المعرفة الصرفية لأن العديد من الدراسات قد أثبتت الآن أن المعرفة الصرفية تسهم في تطوير القراءة والكتابة بالنسبة للطلاب. لقد تم العمل على هذه المراجعة النقدية لدمج النتاتج التي توصلت إليها الدراسات التي سعت إلى تحديد إن كان هذا التدريس قد أسهم في تحسين القراءة والكتابة. يتمحور تحليل الدراسات الستة عشرة التي تخضع لمعايير الانتقاء حول غرض/ أغراض الباحثين في دراسة العلاقة بين تعليم المعرفة الصرفية والمكونات الرئيسية لتطوير القراءة والكتابة ( أي علم الأصوات الكلامية والإملاء ومعنى الكلمة ). تشير النتائج أن للمعرفة الصرفية قدرة على الاسهام في تطوير القراءة والكتابة بالنسبة للطلاب في المجالات الثلاثة – لاسيما عندما تعمق فهم الطلاب للبنية الصرفية والاملاء وكذلك معنى الكلمات المكتوبة. ومع ذلك فإن دراسة التصميم وجودة دراسات تعليم المعرفة الصرفية توحي بأنها مجال ناشئ للبحث. نحتاج إلى القيام بالكثير من الأبحاث من أجل توفير فهم أوضح عن كيف ومتى ولماذا تسهم المعرفة الصرفية في تطوير القراءة والكتابة لدى الطلاب. 现今许多研究已证明词法意识有助学生的读写能力发展,而人们对词法意识在读写教学方面的教育价值之兴趣也日益俱增。本文献综述旨在结合有关确定词法意识教学对改善读写教学成效之研究结果。本文献综述分析16个符合挑选标准的相关研究进行。分析内容围绕着研究者在考查词法意识教学与读写能力发展的关键组成部分(即语音、拼字法,词义)之关系时所持之研究目的。分析结果显示,词法意识教学有促进学生在这三方面的读写能力发展的潜力,而最显著的是在加深学生对书面字词的语素结构、拼写及单词意义之认识方面的潜力。然而,考查词法意识教学研究之设计与素质结果显示这是一个新兴的研究领域。对于词法意识教学如何、何时及为何有助于学生读写能力发展,仍需要进一步研究, 寻求更清晰的认识。 Du fait que beaucoup d'études ont maintenant fait la preuve que la conscience morphologique contribue au développement de la littératie des élèves, il existe un intérêt croissant à l'égard de l'intérêt pédagogique que présente l'enseignement de la morphologie. Cette revue a été entreprise afin d'intégrer les résultats des études conçues pour déterminer si un tel enseignement contribue au développement de la littératie. L'analyse des seize études répondant aux critères de sélection a été effectuée sur les recherches ayant pour but d'étudier la relation entre l'enseignement de la conscience morphologique et des composants‐clé du développement de la littératie (c'est‐à‐dire la phonologie, l'orthographe, la signification des mots). Les résultats montrent que la conscience morphologique peut contribuer au développement de la littératie des élèves dans les trois domaines — elle permet en particulier d'approfondir la compréhension de la structure morphémique, l'orthographe, et la signification des mots écrits. Cependant, l'examen des plans expérimentaux et la qualité des recherches sur la conscience morphologique suggère qu'il s'agit là d'un secteur émergent de recherche. Il reste beaucoup à faire pour comprendre plus clairement comment, quand, et pourquoi la conscience morphologique contribue au développement de la littératie des élèves. Множество исследований свидетельствуют о том, что для развития грамотности учащихся важно понимание морфологического состава слова, поэтому растет интерес к соответствующим обучающим программам. Данный обзор охватывает результаты шестнадцати исследований, которые помогают определить, какой вклад вносят подобные программы в развитие грамотности. Исследования были проанализированы с точки зрения цели или целей, которые ставили перед собой ученые при изучении морфологического сознания учащихся в контексте общего развития грамотности по ключевым компонентам (фонология, орфография, семантика). Результаты подтверждают, что знание морфологии способно продвинуть учащихся во всех трех компонентах грамотности, поскольку углубляется понимание структуры слов, особенностей их написания и смысла. Однако, экспертиза уже предпринятых исследований показывает, что их качество оставляет желать лучшего и эта работа только начинается. Ученым еще предстоит понять как, когда и почему надо заниматься с учениками морфологией и какое значение имеет морфология для развития грамотности. Ya que muchos estudios han mostrado que la conciencia morfológica contribuye al desarrollo de la alfabetización de los estudiantes, está creciendo el interés en el valor docente de la enseñanza de la conciencia morfológica. Este repaso se ha hecho para integrar las conclusiones de estudios que trataron de determinar si dicha instrucción contribuyó al mejoramiento en la alfabetización. El análisis de los 16 estudios que cumplían los criterios de selección fue organizado de acuerdo a los objetivos de los investigadores para estudiar la relación que la instrucción sobre la conciencia morfológica tiene con los componentes claves del desarrollo de la alfabetización (o sea, la fonología, la ortografía, el significado de palabras). Los resultados indican que la conciencia morfológica tiene el potencial de contribuir al desarrollo de la alfabetización de los estudiantes en las tres áreas—particularmente cuando dicha conciencia profundiza el entendimiento de la estructura del morfema, la ortografía, y el significado de las palabras escritas. Sin embargo, la revisión del diseño y la calidad de los estudios de instrucción sobre la conciencia morfológica sugieren que esta área de investigación está comenzando. Falta mucho por hacer para tener un entendimiento claro de cómo, cuándo y por qué la instrucción sobre la conciencia morfológica contribuye al desarrollo de la alfabetización del estudiante.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88040/1/RRQ.45.4.5.pd
- …