Investigation of the Vortex Ring Transition using Scanning Tomo-PIV

The transition of a vortex ring at ReΓ = 5030 is studied by time-resolved scanning tomographic PIV technique. The transition process is first analyzed through flow quantities such as circulation and vorticity components. Using the volumetric measurement technique, vortical organization of the vortex ring at early and late transition stages are visualized respectively. Focus is paid to the instability phenomenon associated with transition. The present 4D flow data allows analysis of the temporal evolution of the wavenumber spectra. The dominant wavenumbers in transition are identified and the growth of their amplitude is revealed. The vortex ring transition is finally studied through the particle trajectories. A phase difference between the axial velocity and radial velocity is found in the beginning of transition, however, it is subject to change following the progression of transition. Statistical analysis on the velocity components helps to identify the aft portion of the inner ring as the one that is first to lose the original phase relation in velocity, which is caused by the secondary vortical activity during transition

E2F-1 Directly Regulates Thrombospondin 1 Expression

Thrombospondin 1 (TSP1) has been shown to play a critical role in inhibiting angiogenesis, resulting in inhibition of tumor growth and metastases. To figure out TSP1's regulators will lead to reveal its biological function mechanistically. In this study, we show that E2F-1 could activate the transcription of TSP1 by both promoter assays and Northern blot. Analysis of various TSP1 promoter mutant constructs showed that a sequence located −144/−137 up-stream of the transcriptional initiation site, related to the consensus E2F-responsive sequence, is necessary for the activation. In consistence with up-regulation of TSP-1 activity by over-expression of E2F-1, the knockdown of endogenous E2F-1 inhibited TSP-1 promoter activity significantly, implying that E2F-1 mediated regulation of TSP-1 is relevant in vivo. In addition, E2F-1 could also directly bind to the TSP1 promoter region covering −144/−137 region as revealed by ChIP assays. Furthermore, the E2F-1-induced activation of TSP1 gene transcription is suppressed by pRB1 in a dose-dependent manner. Taken together, the results demonstrate that TSP1 is a novel target for E2F1, which might imply that E2F-1 can affect angiogenesis by modulating TSP1 expression

Thrombospondins in the heart: potential functions in cardiac remodeling

Cardiac remodeling after myocardial injury involves inflammation, angiogenesis, left ventricular hypertrophy and matrix remodeling. Thrombospondins (TSPs) belong to the group of matricellular proteins, which are non-structural extracellular matrix proteins that modulate cell–matrix interactions and cell function in injured tissues or tumors. They interact with different matrix and membrane-bound proteins due to their diverse functional domains. That the expression of TSPs strongly increases during cardiac stress or injury indicates an important role for them during cardiac remodeling. Recently, the protective properties of TSP expression against heart failure have been acknowledged. The current review will focus on the biological role of TSPs in the ischemic and hypertensive heart, and will describe the functional consequences of TSP polymorphisms in cardiac disease

Evidence for the ‘Good Genes’ Model: Association of MHC Class II DRB Alleles with Ectoparasitism and Reproductive State in the Neotropical Lesser Bulldog Bat, Noctilio albiventris

The adaptive immune system has a major impact on parasite resistance and life history strategies. Immunological defence is costly both in terms of immediate activation and long-term maintenance. The ‘good genes’ model predicts that males with genotypes that promote a good disease resistance have the ability to allocate more resources to reproductive effort which favours the transmission of good alleles into future generations. Our study shows a correlation between immune gene constitution (Major Histocompatibility Complex, MHC class II DRB), ectoparasite loads (ticks and bat flies) and the reproductive state in a neotropical bat, Noctilio albiventris. Infestation rates with ectoparasites were linked to specific Noal-DRB alleles, differed among roosts, increased with body size and co-varied with reproductive state particularly in males. Non-reproductive adult males were more infested with ectoparasites than reproductively active males, and they had more often an allele (Noal-DRB*02) associated with a higher tick infestation than reproductively active males or subadults. We conclude that the individual immune gene constitution affects ectoparasite susceptibility, and contributes to fitness relevant trade-offs in male N. albiventris as suggested by the ‘good genes’ model

Pump Handbook

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Um duelo de fé

Formato: Animação em stop motion com papel - Duração: 3 minutos -Produzido na Oficina de Vídeo-História de 2011-2.Ao peregrinar por um escaldante deserto, um cavaleiro cruzado encontra uma cidade, um local sagrado pela sua religião. Mesmo sozinho ele aproxima-se e decide clamar para a cristandade o local, sem saber que um guerreiro do Islã ainda se encontra lá. Um duelo de fé mostra o embate entre a civilização cristã européia e a civilização muçulmana do Oriente Médio durante as Cruzadas

Anti-idiotypes against anti-H-2 monoclonal antibodies: structural analysis of the molecules induced by in vivo anti-idiotype treatment.

Previous studies have shown that treatment of mice in vivo with xenogeneic anti-idiotype produced against a monoclonal anti-H-2Kk antibody, 11-4.1, leads to the induction of molecules (Id') that inhibit the binding of anti-idiotype to idiotype. To investigate the nature of these Id' molecules, spleens from such anti-idiotype-treated mice were fused with the SP2/0 myeloma to produce monoclonal Id' antibodies. All four monoclonal Id' antibodies were found to react with goat and rabbit anti-11-4.1 in addition to the pig anti-idiotype used for their induction and one of the four, J1-8-1, reacted with syngeneic BALB/c anti-11-4.1. Partial amino acid sequences were determined for the heavy and light chains of these monoclonal antibodies. J1-8-1 heavy chain had an NH2-terminal amino acid sequence identical to that of 11-4.1 for the 39 NH2-terminal residues assigned, whereas its light chain and the heavy and light chains of the other Id' molecules differed markedly from those of the 11-4.1 antibody. Isolated heavy chains and light chains of J1-8-1 and 11-4.1 were reassociated in homologous and heterologous pairs. When J1-8-1 heavy chains and 11-4.1 light chains were mixed in equimolar concentrations, anti-H-2Kk reactivity was found at a level approximately 10% of that observed for reassociated 11-4.1 homologous heavy and light chains. The finding that in vivo anti-idiotype treatment can trigger Id' molecules structurally similar to the original idiotype has implications regarding the mechanism of induction of Id' molecules and the regulation of repertoire expression by idiotypic networks