An investigation of dynamic instability of stiffened rectangular plates

Boundaries of regions of parametric instability of simply supported stiffened rectangular plat

An investigation of the parametric resonance of rectangular plates reinforced with closely spaced stiffeners

Parametric resonance and structural stability model of uniformly reinforced flat plate

Regulation of Humoral Immunity by Pim Kinases: A Dissertation

Pim (Provirus Integration site for Moloney murine leukemia virus) kinases are a family of three serine/threonine kinases involved in cell cycle, survival and metabolism. These kinases were first identified in malignant cells and are most often associated with their role in cancer. Their role in immunity and lymphocytes is less well known. To date, it has been shown that Pim 1 and/or Pim 2 are important for T lymphocyte survival and activation when the Akt signaling pathway is inhibited by rapamycin. In addition, our laboratory has shown that Pim 2 is critical for BLyS-mediated naive B lymphocyte survival in the presence of rapamycin. This thesis extends the role(s) for Pim 1 and/or 2 to include functions during B cell activation and the generation of immune responses. We found that during in vitro activation of purified resting splenic B cells from wild type mice with a variety of activators that use multiple signaling pathways, including the BCR, TLR and CD40 receptors, both Pim 1 and 2 kinases were induced by 48 hours post-activation, suggesting that they could play a role in B cell activation and differentiation to antibody secreting or memory B cells. Immunization of Pim 1-/-2-/- knockout mice with T cell dependent antigens showed impairment in antibody and antibody secreting cell generation as well as lack of germinal center formation clearly demonstrating an involvement of Pim 1 and/or 2 in the immune response. FACS examination of B cell populations from naive Pim 1-/-2-/- knockout mice revealed normal levels of splenic marginal zone and follicular B cells and T cells, however, decreased numbers of all peritoneal B cell populations and decreased B cells in Peyer\u27s Patches was seen. An examination of serum antibody found in naive Pim 1-/-2-/- knockout mice showed decreased levels of natural antibody, which is likely due to loss of the peritoneal B1 cells but does not explain the significantly decreased TD immune response. To determine whether the defect was B cell intrinsic or a more complex interaction between B and T cells, we determined whether Pim 1-/-2-/- mice would respond to T cell independent, TI-1 and TI-2, antigens. Antibody production and antibody secreting cell formation were also significantly decreased in these mice supporting our notion of a B cell intrinsic defect. To further examine the B cell response problem, we attempted to establish chimeric mice using either bone marrow derived cells or fetal liver cells from WT or Pim 1-/-2-/- donors so that the B cells were derived from Pim 1-/-2-/- mice and the T cells would be WT. Unfortunately, we were not able to consistently engraft and develop mature Pim 1-/-2-/- B cells, which indicate that there is a stem cell defect in these knockout mice that requires further investigation. Because one of the major failures in activated Pim 1-/-2-/- B cells is the generation of antibody secreting cells, an analysis of the expression of transcription factors IRF-4 and BLIMP-1, known to play a role in this process was carried out. Although IRF-4 induction was not affected by the loss of Pim 1 and 2, the number of cells able to increase BLIMP-1 expression was significantly decreased, revealing a partial block in the generation of ASCs. Taken together the data presented in this thesis reveals a new and critical role for Pim 1 and 2 kinases in the humoral immune response

The canonical controller and its regularity

This paper deals with properties of canonical controllers. We first specify the behavior that they implement. It follows that a canonical controller implements the desired controlled behavior if and only if the desired behavior is implementable. We subsequently investigate the regularity of the controlled behavior. We prove that a canonical controller is regular if and only if every controller is regular. In other words, canonical controllers are maximally irregular

Genetic Variation in Spatio-Temporal Confined USA300 Community-Associated MRSA Isolates: A Shift from Clonal Dispersion to Genetic Evolution?

NTRODUCTION: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are increasingly isolated, with USA300-0114 being the predominant clone in the USA. Comparative whole genome sequencing of USA300 isolates collected in 2002, 2003 and 2005 showed a limited number of single nucleotide polymorphisms and regions of difference. This suggests that USA300 has undergone rapid clonal expansion without great genomic diversification. However, whole genome comparison of CA-MRSA has been limited to isolates belonging to USA300. The aim of this study was to compare the genetic repertoire of different CA-MRSA clones with that of HA-MRSA from the USA and Europe through comparative genomic hybridization (CGH) to identify genetic clues that may explain the successful and rapid emergence of CA-MRSA. MATERIALS AND METHODS: Hierarchical clustering based on CGH of 48 MRSA isolates from the community and nosocomial infections from Europe and the USA revealed dispersed clustering of the 19 CA-MRSA isolates. This means that these 19 CA-MRSA isolates do not share a unique genetic make-up. Only the PVL genes were commonly present in all CA-MRSA isolates. However, 10 genes were variably present among 14 USA300 isolates. Most of these genes were present on mobile elements. CONCLUSION: The genetic variation present among the 14 USA300 isolates is remarkable considering the fact that the isolates were recovered within one month and originated from a confined geographic area, suggesting continuous evolution of this clone

Eccentric double white dwarfs as LISA sources in globular clusters

We consider the formation of double white dwarfs (DWDs) through dynamical interactions in globular clusters. Such interactions can give rise to eccentric DWDs, in contrast to the exclusively circular population expected to form in the Galactic disk. We show that for a 5-year Laser Interferometer Space Antenna (LISA) mission and distances as far as the Large Magellanic Cloud, multiple harmonics from eccentric DWDs can be detected at a signal-to-noise ratio higher than 8 for at least a handful of eccentric DWDs, given their formation rate and typical lifetimes estimated from current cluster simulations. Consequently the association of eccentricity with stellar-mass LISA sources does not uniquely involve neutron stars, as is usually assumed. Due to the difficulty of detecting (eccentric) DWDs with present and planned electromagnetic observatories, LISA could provide unique dynamical identifications of these systems in globular clusters.Comment: Published in ApJ 665, L5

Black Hole Formation in X-Ray Binaries: The Case of XTE J1118+480

In recent years, an increasing number of proper motions have been measured for Galactic X-ray binaries. When supplemented with accurate determinations of the component masses, orbital period, and donor luminosity and effective temperature, these kinematical constraints harbor a wealth of information on the systems' past evolution. The constraints on compact object progenitors and kicks derived from this are of immense value for understanding compact object formation and exposing common threads and fundamental differences between black hole and neutron star formation. Here, we present the results of such an analysis for the black hole X-ray binary XTE J1118+480. We present results from modeling the mass transfer phase, following the motion in the Galaxy back to the birth site of the black hole, and examining the dynamics of symmetric and asymmetric core-collapses of the black hole progenitor

Clipping the Page – Automatic Article Detection and Marking Software in Production of Newspaper Clippings of a Digitized Historical Journalistic Collection

This paper describes utilization of article detection and extraction on the Finnish Digi (https://digi.kansalliskirjasto.fi/etusivu?set_language=en) newspaper material of the National Library of Finland (NLF) using data of one newspaper, Uusi Suometar 1869–1918. We use PIVAJ software [1] for detection and marking of articles in our collection. Out of the separated articles we can produce automatic clippings for the user. The user can collect clippings for own use both as images and as OCRed text. Together these functionalities improve usability of the digitized journalistic collection by providing a structured access to the contents of a page.Peer reviewe