Shear-induced damped oscillations in an epithelium depend on actomyosin contraction and E-cadherin cell adhesion.

Shear forces between cells occur during global changes in multicellular organization during morphogenesis and tissue growth, yet how cells sense shear forces and propagate a response across a tissue is unknown. We found that applying exogenous shear at the midline of an epithelium induced a local, short-term deformation near the shear plane, and a long-term collective oscillatory movement across the epithelium that spread from the shear-plane and gradually dampened. Inhibiting actomyosin contraction or E-cadherin trans-cell adhesion blocked oscillations, whereas stabilizing actin filaments prolonged oscillations. Combining these data with a model of epithelium mechanics supports a mechanism involving the generation of a shear-induced mechanical event at the shear plane which is then relayed across the epithelium by actomyosin contraction linked through E-cadherin. This causes an imbalance of forces in the epithelium, which is gradually dissipated through oscillatory cell movements and actin filament turnover to restore the force balance across the epithelium

The Enhanced Reading Opportunities Study: Findings from the Second Year of Implementation

According to the National Assessment of Educational Progress, a majority of ninth-graders in low-performing high schools begin their freshman year with significant reading difficulties. Poor reading ability is a key predictor of academic disengagement and, ultimately, dropping out. This report presents findings from the second year of the Enhanced Reading Opportunities (ERO) study, a demonstration and random assignment evaluation of two supplemental literacy programs -- Reading Apprenticeship Academic Literacy and Xtreme Reading -- that aim to improve the reading comprehension skills and school performance of struggling ninth-grade readers

Mechano-transduction: from molecules to tissues.

External forces play complex roles in cell organization, fate, and homeostasis. Changes in these forces, or how cells respond to them, can result in abnormal embryonic development and diseases in adults. How cells sense and respond to these mechanical stimuli requires an understanding of the biophysical principles that underlie changes in protein conformation and result in alterations in the organization and function of cells and tissues. Here, we discuss mechano-transduction as it applies to protein conformation, cellular organization, and multi-cell (tissue) function

The Enhanced Reading Opportunities Study: Early Impact and Implementation Findings

This report presents early findings from a demonstration and random assignment evaluation of two supplemental literacy programs that aim to improve the reading comprehension skills and school performance of struggling ninth-grade readers. On average, the programs produced a positive, statistically significant impact on reading comprehension among students

Increasing β-catenin/Wnt3A activity levels drive mechanical strain-induced cell cycle progression through mitosis.

Mechanical force and Wnt signaling activate β-catenin-mediated transcription to promote proliferation and tissue expansion. However, it is unknown whether mechanical force and Wnt signaling act independently or synergize to activate β-catenin signaling and cell division. We show that mechanical strain induced Src-dependent phosphorylation of Y654 β-catenin and increased β-catenin-mediated transcription in mammalian MDCK epithelial cells. Under these conditions, cells accumulated in S/G2 (independent of DNA damage) but did not divide. Activating β-catenin through Casein Kinase I inhibition or Wnt3A addition increased β-catenin-mediated transcription and strain-induced accumulation of cells in S/G2. Significantly, only the combination of mechanical strain and Wnt/β-catenin activation triggered cells in S/G2 to divide. These results indicate that strain-induced Src phosphorylation of β-catenin and Wnt-dependent β-catenin stabilization synergize to increase β-catenin-mediated transcription to levels required for mitosis. Thus, local Wnt signaling may fine-tune the effects of global mechanical strain to restrict cell divisions during tissue development and homeostasis

Kuwait Special Educators Program

The United States has long been recognized as a world leader in responding to the developmental needs of individuals with mental retar­dation (Rowitz, 1989). Particular strengths exist in the educational arena, both in traditional settings as well as in the vocational area (Glidden & Zetlin, 1992; Clark & Kolstoe, 1990; Wehmen, 1990; Schlack, McGaughey, & Kiernan, 1989). Because of these strengths, an increasing number of inter­national groups are seeking training opportunities to study these practices. In July 1992, the Cultural Attache at the Embassy of Kuwait in Washington, D.C. issued a request for proposals directed at special education practices in the United States. At the University of Hartford, the Division of Univer­sity Programs and Conferences responds to international initiatives of this type, usually in collaboration with the Office of International Studies and one or more of the nine schools and colleges that comprise the university. In this instance, a proposal was developed and submitted in collaboration with the School of Education. The Embassy accepted the proposal. What follows is a description of the program with a focus on curriculum and administrative supports. Issues of replicability along with a discussion of the unique challenges of working with this particular clientele will also be addressed

Experimental Testing and Modeling of 5 kW Oil-Free Open Drive Scroll Expander Using R245fa

Organic Rankine Cycles (ORC) are thermodynamic power cycles designed to generate work from low temperature sources, typically between 80 °C to 270 °C.  The low temperature heat input makes this technology attractive for applications in waste heat recovery from industrial processes, exhaust gas from diesel engines, solar systems, geothermal systems, and others.  The expander has the greatest effect on increasing the efficiency of an ORC. The operating  conditions that the expander is subjected to are directed related to its efficiency.  The performance of a 5 kW scroll expander with a displacement of 73.6 cm3 per revolution, operating at speeds from 500 to 3600 rpm, and using R245fa as the working fluid in a traditional Organic Ranking cycle is experimentally investigated In this paper. Tests were conducted varying the mass flow rate of the working fluid and varying source temperatures, while measuring the effective expander power production and the isentropic efficiency.  The experimental data was then used to develop a model of the scroll expander. Using this model, thermodynamic simulations were carried out for applications similar to exhaust gas waste heat recovery from internal combustion engines