64 research outputs found

    Spin and Chirality Effects in Antler-Topology Processes at High Energy e+ee^+e^- Colliders

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    We perform a model-independent investigation of spin and chirality correlation effects in the antler-topology processes e+eP+P(+D0)(Dˉ0)e^+e^-\to\mathcal{P}^+\mathcal{P}^-\to (\ell^+ \mathcal{D}^0) (\ell^-\mathcal{\bar{D}}^0) at high energy e+ee^+e^- colliders with polarized beams. Generally the production process e+eP+Pe^+e^-\to\mathcal{P}^+\mathcal{P}^- can occur not only through the ss-channel exchange of vector bosons, V0\mathcal{V}^0, including the neutral Standard Model (SM) gauge bosons, γ\gamma and ZZ, but also through the ss- and tt-channel exchanges of new neutral states, S0\mathcal{S}^0 and T0\mathcal{T}^0, and the uu-channel exchange of new doubly-charged states, U\mathcal{U}^{--}. The general set of (non-chiral) three-point couplings of the new particles and leptons allowed in a renormalizable quantum field theory is considered. The general spin and chirality analysis is based on the threshold behavior of the excitation curves for P+P\mathcal{P}^+\mathcal{P}^- pair production in e+ee^+e^- collisions with longitudinal and transverse polarized beams, the angular distributions in the production process and also the production-decay angular correlations. In the first step, we present the observables in the helicity formalism. Subsequently, we show how a set of observables can be designed for determining the spins and chiral structures of the new particles without any model assumptions. Finally, taking into account a typical set of approximately chiral invariant scenarios, we demonstrate how the spin and chirality effects can be probed experimentally at a high energy e+ee^+e^- collider.Comment: 50 pages, 14 figures, 6 tables, matches version published in EPJ

    Anti-Helicobacter pylori activity and immunostimulatory effect of extracts from Byrsonima crassa Nied. (Malpighiaceae)

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    <p>Abstract</p> <p>Background</p> <p>Several <it>in vitro </it>studies have looked at the effect of medicinal plant extracts against <it>Helicobacter pylori </it>(<it>H. pylori</it>). Regardless of the popular use of <it>Byrsonima crassa </it>(<it>B. crassa</it>) as antiemetic, diuretic, febrifuge, to treat diarrhea, gastritis and ulcers, there is no data on its effects against <it>H. pylori</it>. In this study, we evaluated the anti-<it>H. pylori </it>of <it>B. crassa </it>leaves extracts and its effects on reactive oxygen/nitrogen intermediates induction by murine peritoneal macrophages.</p> <p>Methods</p> <p>The minimal inhibitory concentration (MIC) was determined by broth microdilution method and the production of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and nitric oxide (NO) by the horseradish peroxidase-dependent oxidation of phenol red and Griess reaction, respectively.</p> <p>Results</p> <p>The methanolic (MeOH) and chloroformic (CHCl<sub>3</sub>) extracts inhibit, <it>in vitro</it>, the growth of <it>H. pylori </it>with MIC value of 1024 μg/ml. The MeOH extract induced the production H<sub>2</sub>O<sub>2 </sub>and NO, but CHCl<sub>3 </sub>extract only NO.</p> <p>Conclusion</p> <p>Based in our results, <it>B. crassa </it>can be considered a source of compounds with anti-<it>H. pylori </it>activity, but its use should be done with caution in treatment of the gastritis and peptic ulcers, since the reactive oxygen/nitrogen intermediates are involved in the pathogenesis of gastric mucosal injury induced by ulcerogenic agents and <it>H. pylori </it>infections.</p

    Purified native and recombinant human alpha lymphotoxin [tumor necrosis factor (TNF)-beta] induces inflammatory reactions in normal skin

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    These studies report findings that demonstrate that human alpha lymphotoxin (LT) induces local, visible, and microscopic inflammatory reactions in normal skin. Skin sites in rabbits, when inoculated with a single injection of native or recombinant human alpha lymphotoxin, demonstrated erythema, swelling, and warmth within 5 hr. Erythema peaked between 24 and 48 hr had resolved by 72 hr. Histologic studies of skin sites injected with native LT revealed polymorphonuclear neutrophil (PMN) infiltration and edema beginning as early as 3 hr posttreatment. Individual skin sites that received three daily injections of native LT exhibited persistent erythema and swelling. Palpable induration was evident 24 hr after the second injection in the series. Histologic examination revealed the presence of many PMNs with associated focal dermal destruction, in the form of microabscesses, and scattered mononuclear cells. In contrast, control materials and recombinant human tumor necrosis factor (TNF-alpha) did not induce visible skin reactions in the rabbit. Several additional controls excluded endotoxin as being the agent responsible for the inflammatory skin reactions observed. The ability of LT to induce inflammation may have a role in its antitumor activity and it may be an important endogenous mediator in other immunologic reactions

    Differentiating Embryonic Stem Cells Pass through ‘Temporal Windows’ That Mark Responsiveness to Exogenous and Paracrine Mesendoderm Inducing Signals

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    BACKGROUND: Mesendoderm induction during embryonic stem cell (ESC) differentiation in vitro is stimulated by the Transforming Growth Factor and Wingless (Wnt) families of growth factors. PRINCIPAL FINDINGS: We identified the periods during which Bone Morphogenetic Protein (BMP) 4, Wnt3a or Activin A were able to induce expression of the mesendoderm marker, Mixl1, in differentiating mouse ESCs. BMP4 and Wnt3a were required between differentiation day (d) 1.5 and 3 to most effectively induce Mixl1, whilst Activin A induced Mixl1 expression in ESC when added between d2 and d4, indicating a subtle difference in the requirement for Activin receptor signalling in this process. Stimulation of ESCs with these factors at earlier or later times resulted in little Mixl1 induction, suggesting that the differentiating ESCs passed through 'temporal windows' in which they sequentially gained and lost competence to respond to each growth factor. Inhibition of either Activin or Wnt signalling blocked Mixl1 induction by any of the three mesendoderm-inducing factors. Mixing experiments in which chimeric EBs were formed between growth factor-treated and untreated ESCs revealed that BMP, Activin and Wnt signalling all contributed to the propagation of paracrine mesendoderm inducing signals between adjacent cells. Finally, we demonstrated that the differentiating cells passed through 'exit gates' after which point they were no longer dependent on signalling from inducing molecules for Mixl1 expression. CONCLUSIONS: These studies suggest that differentiating ESCs are directed by an interconnected network of growth factors similar to those present in early embryos and that the timing of growth factor activity is critical for mesendoderm induction

    A next generation, pilot-scale continuous sterilization system for fermentation media

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    A new continuous sterilization system was designed, constructed, started up, and qualified for media sterilization for secondary metabolite cultivations, bioconversions, and enzyme production. An existing Honeywell Total Distributed Control 3000-based control system was extended using redundant High performance Process Manager controllers for 98 I/O (input/output) points. This new equipment was retrofitted into an industrial research fermentation pilot plant, designed and constructed in the early 1980s. Design strategies of this new continuous sterilizer system and the expanded control system are described and compared with the literature (including dairy and bio-waste inactivation applications) and the weaknesses of the prior installation for expected effectiveness. In addition, the reasoning behind selection of some of these improved features has been incorporated. Examples of enhancements adopted include sanitary heat exchanger (HEX) design, incorporation of a “flash” cooling HEX, on-line calculation of F(o) and R(o), and use of field I/O modules located near the vessel to permit low-cost addition of new instrumentation. Sterilizer performance also was characterized over the expected range of operating conditions. Differences between design and observed temperature, pressure, and other profiles were quantified and investigated

    Autologous microsurgical breast reconstruction and coronary artery bypass grafting: an anatomical study and clinical implications

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    OBJECTIVE: To identify possible avenues of sparing the internal mammary artery (IMA) for coronary artery bypass grafting (CABG) in women undergoing autologous breast reconstruction with deep inferior epigastric artery perforator (DIEP) flaps. BACKGROUND: Optimal autologous reconstruction of the breast and coronary artery bypass grafting (CABG) are often mutually exclusive as they both require utilisation of the IMA as the preferred arterial conduit. Given the prevalence of both breast cancer and coronary artery disease, this is an important issue for women's health as women with DIEP flap reconstructions and women at increased risk of developing coronary artery disease are potentially restricted from receiving this reconstructive option should the other condition arise. METHODS: The largest clinical and cadaveric anatomical study (n=315) to date was performed, investigating four solutions to this predicament by correlating the precise requirements of breast reconstruction and CABG against the anatomical features of the in situ IMAs. This information was supplemented by a thorough literature review. RESULTS: Minimum lengths of the left and right IMA needed for grafting to the left-anterior descending artery are 160.08 and 177.80 mm, respectively. Based on anatomical findings, the suitable options for anastomosis to each intercostals space are offered. In addition, 87-91% of patients have IMA perforator vessels to which DIEP flaps can be anastomosed in the first- and second-intercostal spaces. CONCLUSION: We outline five methods of preserving the IMA for future CABG: (1) lowering the level of DIEP flaps to the fourth- and fifth-intercostals spaces, (2) using the DIEP pedicle as an intermediary for CABG, (3) using IMA perforators to spare the IMA proper, (4) using and end-to-side anastomosis between the DIEP pedicle and IMA and (5) anastomosis of DIEP flaps using retrograde flow from the distal IMA. With careful patient selection, we hypothesize using the IMA for autologous breast reconstruction need not be an absolute contraindication for future CABG
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