Novel regulation of mitotic exit by the Cdc42 effectors Gic1 and Gic2

Copyright @ The Rockefeller University PressThe guanine nucleotide exchange factor Cdc24, the GTPase Cdc42, and the Cdc42 effectors Cla4 and Ste20, two p21-activated kinases, form a signal transduction cascade that promotes mitotic exit in yeast. We performed a genetic screen to identify components of this pathway. Two related bud cortex–associated Cdc42 effectors, Gic1 and Gic2, were obtained as factors that promoted mitotic exit independently of Ste20. The mitotic exit function of Gic1 was dependent on its activation by Cdc42 and on the release of Gic1 from the bud cortex. Gic proteins became essential for mitotic exit when activation of the mitotic exit network through Cdc5 polo kinase and the bud cortex protein Lte1 was impaired. The mitotic exit defect of cdc5-10 Δlte1 Δgic1 Δgic2 cells was rescued by inactivation of the inhibiting Bfa1-Bub2 GTPase-activating protein. Moreover, Gic1 bound directly to Bub2 and prevented binding of the GTPase Tem1 to Bub2. We propose that in anaphase the Cdc42-regulated Gic proteins trigger mitotic exit by interfering with Bfa1-Bub2 GTPase-activating protein function.The work of E. Schiebel is supported by Cancer Research UK

Determination of the Rocking Curve and Reflection Efficiency of a Quartz Crystal X-ray Imager

A spherically curved Bragg crystal was characterized for use in experiments utilizing the Kα emissions of higher Z materials than current crystals allow. The National Synchrotron Light Source at Brookhaven National Laboratory was used to study the crystal with x-rays of energies 15.6909 keV, 16.5210 keV, 17.4793 keV, and 22.1629 keV corresponding to Zr Kα2, Nb Kα2, Mo Kα1 and Ag Kα2 emissions, respectively. The crystal was then used to image the Kα emission from a Zr target irradiated using the multi-terawatt laser at the University of Rochester. In conclusion the crystal was a successful diagnostic, and provided the first ever image of Zr Kα radiation.United States of America Department of EnergyNo embarg

Cruise Report R.V. POSEIDON POS308

06.03.-22.03.200

Building Comprehension In Fifth Grade Students Using Guided Reading.

Guided reading is a strategy used in reading instruction. This project aims to answer the question, what is the impact of comprehension strategies when they are incorporated into a guided reading lesson plan in fifth grade? The author describes their personal and professional experience that led them to this question. The research literature on guided reading, comprehension, metacognition and assessment explain the importance of each and how they can be implemented in a classroom. Then the curriculum project is explained. The curriculum includes guided reading lesson plans and assessments by using the Understanding by Design framework. This curriculum is intended to provide teachers with explicit teaching points and strategies to incorporate metacognition

Bentonite bonded moulding sands

Sand moulded casting is still one of the most efficient and cheapest methods to produce metal parts of complex shapes. Due to their cyclic reusability and low emission of particles and organic compounds during casting, bentonite bonded sands have an excellent environmental performance. Moreover, sands discarded after a maximum of cycles can be reused as raw material for in various applications. Wet tensile strength testing is a common method to assess the quality of bentonite bonded moulding sands. For wet tensile strength testing, a specimen is first heated from above in order to simulate heat-driven moisture transport induced by the casting process. Then, stress is applied until the specimen ruptures. In the first part of this study, neutron radiography imaging was applied to moulding sands in-situ during heating and wet tensile strength testing in order to investigate the effects of water kinematics on the tensile strength. Neutron radiography allowed the localization of the rupture plane and the quantitative determination of the local water content with sub-mm resolution. Quantification of the temperature of the rupture plane and of the heat kinematics within the specimen was accomplished by temperature measurements both in-situ and ex-situ. In this way, experimental data correlating the wet tensile strength with the specific conditions of moulding sands at the rupture plane were obtained for the first time. Series of experiments with different initial sand moisture contents were conducted. The results show that the weakest location within a sand profile can be pinpointed at the interface between evaporation and condensation zone (i.e., at the 100°C isotherm), where water vaporisation starts and the water bridges connecting the sand grains collapse. During casting, however, the moulding sand undergoes irreversible alterations, which deteriorate its properties. Aim of this work, therefore, was to gain accurate insights into the relation between sand alteration and property change. To this end, the wet tensile strengths of heat pre-treated and cyclically reused sands were related to the kinematics of water within the sand as measured by in-situ neutron radiography and neutron diffraction. Sands subjected to 22 cycles of drying (T = 120°C) and remoistening (3 wt.%) revealed modifications in smectite lattice spacings and in water release behaviour from smectite interlayers. No significant change of tensile strength, however, was associated with these modifications. Contrarily, sands pre-treated with temperatures as low as 225°C revealed a reduction of tensile strength which was correlated with irreversible modifications of the structural and compositional integrity of the smectites as manifested by substantially altered water kinematics. The results show that cyclic use of moulding sand has little impact on the sand quality as long as the temperature of the sand remains low. For the practice in foundry, the results imply that a rigorous separation of heat-exposed sand is advantageous. Sands bonded with sodium- and calcium-bentonite were studies in order to unravel the influence of the exchangeable cation on the binding properties. Changes in tensile strength as well as in heat and mass transport within the sand were investigated. Heat pre-treated Ca- and Na-bentonite bonded sand revealed differences in tensile strength. Although no major differences in the swelling behaviour could be detected, Na-bentonite bonded sands have a better mechanical performance than Ca-bentonite bonded sands both before and after the pre-treatment. The measured changes in tensile strength of both Ca- and Na-bentonite bonded sand correspond well with the irreversible alterations of the smectites

Identification and Characterisation of Technological Topics in the Field of Molecular Biology

This paper focuses on methodological approaches for characterising the specific topics within a technological field based on scientific literature data. We introduce a diachronic clustering analysis approach and some bibliometric indicators. The results are visualised with the software-tool Stanalyst [1]. We are applying our methods to the field "Molecular Biology". This field has grown a great deal in the last decade