Reactions of fluorine and bromine atoms

Hydrocarbons (chiefly the lower alkanes) have been fluorinated by a competitive method in a high vacuum, all glass, static system. Monofluorides formed by hydrogen abstraction from pairs of reactants have been measured by gas chromatography and ratios of A factors and activation energy differences found for reactions of the type,F• + RH —» HF + R•Absolute A factors for (2) have been obtained by assuming that the A factor for ethane calculated from transition -state theory was the same as the experimental A factor. Absolute activation energies for reaction (2) have also been obtained by assuming the activation energies for the higher of the alkanes investigated were zero.Bromine hydrogen abstraction reactions analogous to (2) have been investigated by a similar method. Absolute A factors and activation energies have been derived by relating the results to the previously found parameters for bromine atom hydrogen abstraction from methyl bromide.Previous work, both quantitative and qualitative, of bromine and fluorine atom hydrogen abstraction and related reactions has been described and the kinetic data summarised. The activation energies and A factors obtained here for bromine and fluorine atoms have been compared with previously found figures for chlorine. Good agreement has been found between experimental A factors and values calculated from transition -state theory.From the bromine work carbon -hydrogen bond strengths have been derived which compare well with the generally accepted values. In order to obtain more accurate values a method has been developed for obtaining the activation energies of reactions of the type,R• + HBr —» RH + Br•Preliminary results are reported. Arrhenius parameters for other reactions in the bromine hydrocarbon systems have been considered. Future work has been suggested

Synthèse et études conformationnelles de motifs stabilisant des structures secondaires de peptides

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Densities of short uniform random walks

We study the densities of uniform random walks in the plane. A special focus is on the case of short walks with three or four steps and less completely those with five steps. As one of the main results, we obtain a hypergeometric representation of the density for four steps, which complements the classical elliptic representation in the case of three steps. It appears unrealistic to expect similar results for more than five steps. New results are also presented concerning the moments of uniform random walks and, in particular, their derivatives. Relations with Mahler measures are discussed.Comment: 32 pages, 9 figure

Chimeric protein and nano-construct for tissue-retained enzyme to locally suppress inflammation

There is considerable need for new retention strategies of immunomodulatory biologics for localized suppression of inflammation. We developed a chimeric protein as a well as a self-assembled nano-construct incorporating novel approaches for both retention and suppression to induce potent, confined metabolic programming. Immunosuppressive indoleamine 2,3 dioxygenase (IDO), which depletes tryptophan through the kynurenine pathway, was fused to Galectin 3 (Gal3), which binds extracellular glycans and provides tissue anchoring. Using a luciferase-Gal3 fusion reporter, tissue retention was prolonged to ~6 d whereas native luciferase is not retained and undetectable by 24 h. IDO-Gal3 injected subcutaneously controlled local LPS-challenged tissue inflammation. Furthermore, subgingival injection suppressed periodontal disease (PD) in a polymicrobial challenged mouse model. Multiplex analysis of gingival tissue revealed decreased inflammatory (IL-1β, IL-12p70, KC, IP10, MCP1, MIP2) and increased anti-inflammatory (IL-10, TGFβ3) proteins, indicating a shift toward homeostasis. Animals treated with IDO-Gal3 also showed significant decrease in bone loss commonly associated with PD, as determined by µCT analysis

Computing Fresnel integrals via modified trapezium rules

In this paper we propose methods for computing Fresnel integrals based on truncated trapezium rule approximations to integrals on the real line, these trapezium rules modified to take into account poles of the integrand near the real axis. Our starting point is a method for computation of the error function of complex argument due to Matta and Reichel (J Math Phys 34:298–307, 1956) and Hunter and Regan (Math Comp 26:539–541, 1972). We construct approximations which we prove are exponentially convergent as a function of N , the number of quadrature points, obtaining explicit error bounds which show that accuracies of 10−15 uniformly on the real line are achieved with N=12 , this confirmed by computations. The approximations we obtain are attractive, additionally, in that they maintain small relative errors for small and large argument, are analytic on the real axis (echoing the analyticity of the Fresnel integrals), and are straightforward to implement

Intracellular immune sensing promotes inflammation via gasdermin D–driven release of a lectin alarmin

Inflammatory caspase sensing of cytosolic lipopolysaccharide (LPS) triggers pyroptosis and the concurrent release of damage-associated molecular patterns (DAMPs). Collectively, DAMPs are key determinants that shape the aftermath of inflammatory cell death. However, the identity and function of the individual DAMPs released are poorly defined. Our proteomics study revealed that cytosolic LPS sensing triggered the release of galectin-1, a β-galactoside-binding lectin. Galectin-1 release is a common feature of inflammatory cell death, including necroptosis. In vivo studies using galectin-1-deficient mice, recombinant galectin-1 and galectin-1-neutralizing antibody showed that galectin-1 promotes inflammation and plays a detrimental role in LPS-induced lethality. Mechanistically, galectin-1 inhibition of CD45 (Ptprc) underlies its unfavorable role in endotoxin shock. Finally, we found increased galectin-1 in sera from human patients with sepsis. Overall, we uncovered galectin-1 as a bona fide DAMP released as a consequence of cytosolic LPS sensing, identifying a new outcome of inflammatory cell death.Fil: Russo, Ashley J.. UConn Health School of Medicine; Estados UnidosFil: Vasudevan, Swathy O.. UConn Health School of Medicine; Estados UnidosFil: Mendez Huergo, Santiago Patricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Kumari, Puja. UConn Health School of Medicine; Estados UnidosFil: Menoret, Antoine. UConn Health School of Medicine; Estados UnidosFil: Duduskar, Shivalee. Jena University Hospital; AlemaniaFil: Wang, Chengliang. UConn Health School of Medicine; Estados UnidosFil: Pérez Sáez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Fettis, Margaret M.. University of Florida; Estados UnidosFil: Li, Chuan. UConn Health School of Medicine; Estados UnidosFil: Liu, Renjie. University of Florida; Estados UnidosFil: Wanchoo, Arun. University of Florida; Estados UnidosFil: Chandiran, Karthik. UConn Health School of Medicine; Estados UnidosFil: Ruan, Jianbin. UConn Health School of Medicine; Estados UnidosFil: Vanaja, Sivapriya Kailasan. UConn Health School of Medicine; Estados UnidosFil: Bauer, Michael. Jena University Hospital; AlemaniaFil: Sponholz, Christoph. Jena University Hospital; AlemaniaFil: Hudalla, Gregory A.. University of Florida; Estados UnidosFil: Vella, Anthony T.. UConn Health School of Medicine; Estados UnidosFil: Zhou, Beiyan. UConn Health School of Medicine; Estados UnidosFil: Deshmukh, Sachin D.. Jena University Hospital; AlemaniaFil: Rabinovich, Gabriel Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rathinam, Vijay A.. UConn Health School of Medicine; Estados Unido