DotB : Legionella pneumophila's Dot/Icm Type IV Secretion System's AAA+ motor

The Gram-negative bacteria Legionella pneumophila is the causative agent of a severe form of pneumonia known as Legionnaire's Disease. Legionella utilizes its Defect in organelle trafficking/Intracellular multiplication Type IV Secretion System (Dot/Icm T4SS) to secrete over 300 effector proteins into the cytoplasm of alveolar macrophages for infection. The Dot/Icm T4SS has a Type IV Coupling Complex (T4CC) which has been identified to help recruit effector proteins for translocation during infection. However, not all effector proteins are translocated by the T4CC. DotB is a cytosolic ATPase from the pathogenic Legionella pneumophila and is suggested to mediate translocation of specific effector proteins during infection. DotB is a member of the ATPases associated with diverse cellular activities (AAA+) protein family. Characterization of DotB thus far has revealed its ability to form a complex with other T4SS-components and to function as an ATPase that plays a role with translocation. However, much remains unknown about the function of DotB. Earlier studies suggest that DotB may not only function to translocate proteins but can also help mediate other processes such as plasmid transfer and cytotoxicity. Thus, there is a need to further study and understand what proteins DotB can translocate. This review gives insight into the functions DotB may have within Legionella and suggests experimental approaches to further characterize DotB's role in the translocation of effector proteins.Includes bibliographical references

F17RS SGR No. 22 (Election Ballot Desired Name)

A RESOLUTION Urging and Requesting the Election to add a space for Desired Ballot Names on the Candidate Filing For

F17RS SGR No. 23 (Election Recruitment)

A RESOLUTION Urging and Requesting Efforts to Improve Election Recruitment Processe

Identifying and Scheduling Loop Chains Using Directives

Exposing opportunities for parallelization while explicitly managing data locality is the primary challenge to porting and optimizing existing computational science simulation codes to improve performance and accuracy. OpenMP provides many mechanisms for expressing parallelism, but it primarily remains the programmer’s responsibility to group computations to improve data locality. The loopchain abstraction, where data access patterns are included with the specification of parallel loops, provides compilers with sufficient information to automate the parallelism versus data locality tradeoff. In this paper, we present a loop chain pragma and an extension to the omp for to enable the specification of loop chains and high-level specifications of schedules on loop chains. We show example usage of the extensions, describe their implementation, and show preliminary performance results for some simple examples

Layered wicks enable passive transport of condensation out of cooling systems

Layered wicks enable passive transport of condensation out of cooling systems Nhicolas Aponte, Jordan Morrow, Gennifer Riley, Partha Chakraborty, Melanie M. Derby Department of Mechanical and Nuclear Engineering, Kansas State University Cooling systems, like condensers or cooling towers of a power plant, transfer heat out of a system. The cooling process often occurs through the condensation of water, which forms a liquid film that reduces heat transfer. This problem makes cooling systems larger and more costly. One approach to this problem is drop-wise condensation in which condensed water gathers in the form of droplets which can then run off, preventing the reduction of heat transfer caused by the liquid film. For this solution to be effective in industry, a hydrophobic coating would need to last over 10 years, which is difficult to achieve. The approach studied in this work uses the capillary/surface tension forces to passively transport water, which is applicable to removing liquid films from condensers. This is investigated by using a wick, which is a structure that enables the passive transport of water. In this project, we compare wicking structures with different porosity in order to design an effective wick for industrial use. The wicks used are an array of layered spheres bridged by cylindrical columns with calculated porosity of 0.35(Wick C), 0.42(Wick B), and 0.66(Wick A). The wicks are 3-D printed onto a test plate, which allows the fabrication of complex geometries. The effectiveness of the wicks is compared using the rate-of-rise method. For this method, the wicks are lowered into a water reservoir. The interactions between the wick and the water are observed and recorded under a high speed camera. Then, the height the water rises to within the wick is compared. The wicks printed for this project outline problems we did not account for. The small pore volume of the wicks made it difficult to clean out support material after being printed. Future wicks will be designed with a greater pore volume than that of Wick C. The success of this project could improve the heat transfer in space cooling systems and power plant condensers

An Additional Pulsating Mode (7.35 mHz) and Pulsations Timing Variations of PG 1613+426

We present the detection of an additional pulsation mode (7.35 mHz) of a subdwarf B star, PG 1613+426, and periodic Observed minus Calculated (O-C) variations for two existing pulsations. PG 1613+426 is near the hot end of the sdB instability strip. One pulsation mode (6.94 mHz) was detected so far by Bonanno et al. (2002) and another pulsation mode candidate (7.05 mHz) was proposed with a confidence level above 90% by Kuassivi and Ferlet (2005). To constrain sdB star evolutional scenarios, this star was monitored in 2010, 2011, 2015, and 2017 as a part of a project for finding companions to sdB stars using the pulsation timing method. The photometric analysis of those data shows an additional 7.35 mHz pulsation mode as well as the previously detected 6.93 mHz mode. However the 7.05 mHz mode was not detected. Nightly amplitude changes of 7.35 mHz mode were observed in the 2011 data, however the 2017 data did not show nightly amplitude shifts. O-C variations were detected in both 6.93 mHz and 7.35 mHz pulsations, indicating that PG 1613+426 may have a low mass companion star. However, more observations are needed to confirm it