TRIP13PCH-2 promotes Mad2 localization to unattached kinetochores in the spindle checkpoint response.

The spindle checkpoint acts during cell division to prevent aneuploidy, a hallmark of cancer. During checkpoint activation, Mad1 recruits Mad2 to kinetochores to generate a signal that delays anaphase onset. Yet, whether additional factors contribute to Mad2's kinetochore localization remains unclear. Here, we report that the conserved AAA+ ATPase TRIP13(PCH-2) localizes to unattached kinetochores and is required for spindle checkpoint activation in Caenorhabditis elegans. pch-2 mutants effectively localized Mad1 to unattached kinetochores, but Mad2 recruitment was significantly reduced. Furthermore, we show that the C. elegans orthologue of the Mad2 inhibitor p31(comet)(CMT-1) interacts with TRIP13(PCH-2) and is required for its localization to unattached kinetochores. These factors also genetically interact, as loss of p31(comet)(CMT-1) partially suppressed the requirement for TRIP13(PCH-2) in Mad2 localization and spindle checkpoint signaling. These data support a model in which the ability of TRIP13(PCH-2) to disassemble a p31(comet)/Mad2 complex, which has been well characterized in the context of checkpoint silencing, is also critical for spindle checkpoint activation

A Model for Partial Viscous Sintering

A mathematical model describing the sintering rate of a viscous material powder bed is presented. This model assumes that the powder bed is composed of cubic packed, equal-size spherical particles. The sintering rate equation is derived in terms of a unit cell dimension or the relative density of a powder bed. A mathematical factor, fraction of sintering, is introduced to explain the phenomena of partial sintering. Key words: model, viscous sintering.Mechanical Engineerin

Precision Position Control Using an RGB Sensor and Linearized Output Variable-Intensity Color Array

This thesis presents the design and implementation of a single degree-of-freedom (DOF) position control algorithm, using a red-green-blue (RGB) color sensor and a linearized color array. This work was implemented on a pre-existing magnetic-levitation (maglev) test bed with decoupled controllers for each of the 6 DOFs. The RGB sensor was attached horizontally onto a cantilever beam away from the moving platen and centered over a strip with varying RGB intensity values of the color red. The intensity values that make up the red strip were linearized based upon the response of the sensor as it was moved across the color strip. This linear sensor response was then used to develop a first-order curve-fit to relate position in the y-axis to the sensor output. The functionality of the control algorithm was verified through a series of step responses and continuous motion test runs. The position resolution, in the axis of movement, was demonstrated to be better than 30 µm. Experimental results of both the position response and linearization process are presented herein

Alumni Notes

Schedule of upcoming events, brief articles about alumni activities, and a column by the alumni directo