385 research outputs found

    Iodoarene-Catalyzed Cyclizations of Unsaturated Amides

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    The cyclization of N-alkenylamides catalyzed by iodoarenes under oxidative conditions is presented. Five-, six-, and seven-membered rings with a range of substitutions can be prepared by this route. Preliminary data from the use of chiral iodoarenes as precatalysts show that enantiocontrol is feasible

    Rendezvous of Heterogeneous Mobile Agents in Edge-weighted Networks

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    We introduce a variant of the deterministic rendezvous problem for a pair of heterogeneous agents operating in an undirected graph, which differ in the time they require to traverse particular edges of the graph. Each agent knows the complete topology of the graph and the initial positions of both agents. The agent also knows its own traversal times for all of the edges of the graph, but is unaware of the corresponding traversal times for the other agent. The goal of the agents is to meet on an edge or a node of the graph. In this scenario, we study the time required by the agents to meet, compared to the meeting time TOPTT_{OPT} in the offline scenario in which the agents have complete knowledge about each others speed characteristics. When no additional assumptions are made, we show that rendezvous in our model can be achieved after time O(nTOPT)O(n T_{OPT}) in a nn-node graph, and that such time is essentially in some cases the best possible. However, we prove that the rendezvous time can be reduced to Θ(TOPT)\Theta (T_{OPT}) when the agents are allowed to exchange Θ(n)\Theta(n) bits of information at the start of the rendezvous process. We then show that under some natural assumption about the traversal times of edges, the hardness of the heterogeneous rendezvous problem can be substantially decreased, both in terms of time required for rendezvous without communication, and the communication complexity of achieving rendezvous in time Θ(TOPT)\Theta (T_{OPT})

    ÉTUDE EXPÉRIMENTALE ET THÉORIQUE DES NOYAUX DE TRANSITION 68,70,72,74Ge

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    Les isotopes de 68,70,72,74Ge ont été étudiés avec une haute résolution en énergie au moyen de la réaction (p, t). Un grand nombre de nouveaux niveaux 0+, 2+ et 4+ à basse énergie ont été mis en évidence. Des calculs semi-microscopiques de surfaces d'énergie potentielle et de spectres ont été effectués et des conclusions sont données sur la structure des noyaux Ge

    Sex differences in the impact of ozone on survival and alveolar macrophage function of mice after Klebsiella pneumoniae infection

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    <p>Abstract</p> <p>Background</p> <p>Sex differences have been described in a number of pulmonary diseases. However, the impact of ozone exposure followed by pneumonia infection on sex-related survival and macrophage function have not been reported. The purpose of this study was to determine whether ozone exposure differentially affects: 1) survival of male and female mice infected with <it>Klebsiella pneumoniae</it>, and 2) the phagocytic ability of macrophages from these mice.</p> <p>Methods</p> <p>Male and female C57BL/6 mice were exposed to O<sub>3 </sub>or to filtered air (FA) (control) and then infected intratracheally with <it>K. pneumoniae </it>bacteria. Survival was monitored over a 14-day period, and the ability of alveolar macrophages to phagocytize the pathogen <it>in vivo </it>was investigated after 1 h.</p> <p>Results</p> <p>1) Both male and female mice exposed to O<sub>3 </sub>are significantly more susceptible to <it>K. pneumoniae </it>infection than mice treated with FA; 2) although females appeared to be more resistant to <it>K. pneumoniae </it>than males, O<sub>3 </sub>exposure significantly increased the susceptibility of females to <it>K. pneumoniae </it>infection to a greater degree than males; 3) alveolar macrophages from O<sub>3</sub>-exposed male and female mice have impaired phagocytic ability compared to macrophages from FA-exposed mice; and 4) the O<sub>3</sub>-dependent reduction in phagocytic ability is greater in female mice.</p> <p>Conclusion</p> <p>O<sub>3 </sub>exposure reduces the ability of mice to survive <it>K. pneumoniae </it>infection and the reduced phagocytic ability of alveolar macrophages may be one of the contributing factors. Both events are significantly more pronounced in female mice following exposure to the environmental pollutant, ozone.</p

    Adaptor SKAP-55 Binds p21ras Activating Exchange Factor RasGRP1 and Negatively Regulates the p21ras-ERK Pathway in T-Cells

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    While the adaptor SKAP-55 mediates LFA-1 adhesion on T-cells, it is not known whether the adaptor regulates other aspects of signaling. SKAP-55 could potentially act as a node to coordinate the modulation of adhesion with downstream signaling. In this regard, the GTPase p21ras and the extracellular signal-regulated kinase (ERK) pathway play central roles in T-cell function. In this study, we report that SKAP-55 has opposing effects on adhesion and the activation of the p21ras -ERK pathway in T-cells. SKAP-55 deficient primary T-cells showed a defect in LFA-1 adhesion concurrent with the hyper-activation of the ERK pathway relative to wild-type cells. RNAi knock down (KD) of SKAP-55 in T-cell lines also showed an increase in p21ras activation, while over-expression of SKAP-55 inhibited activation of ERK and its transcriptional target ELK. Three observations implicated the p21ras activating exchange factor RasGRP1 in the process. Firstly, SKAP-55 bound to RasGRP1 via its C-terminus, while secondly, the loss of binding abrogated SKAP-55 inhibition of ERK and ELK activation. Thirdly, SKAP-55−/− primary T-cells showed an increased presence of RasGRP1 in the trans-Golgi network (TGN) following TCR activation, the site where p21ras becomes activated. Our findings indicate that SKAP-55 has a dual role in regulating p21ras-ERK pathway via RasGRP1, as a possible mechanism to restrict activation during T-cell adhesion

    Towards global consensus on core outcomes for hidradenitis suppurativa research: an update from the HISTORIC consensus meetings I and II

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    Background A core outcomes set (COS) is an agreed minimum set of outcomes that should be measured and reported in all clinical trials for a specific condition. Hidradenitis suppurativa (HS) has no agreed‐upon COS. A central aspect in the COS development process is to identify a set of candidate outcome domains from a long list of items. Our long list had been developed from patient interviews, a systematic review of the literature and a healthcare professional survey, and initial votes had been cast in two e‐Delphi surveys. In this manuscript, we describe two in‐person consensus meetings of Delphi participants designed to ensure an inclusive approach to generation of domains from related items. Objectives To consider which items from a long list of candidate items to exclude and which to cluster into outcome domains. Methods The study used an international and multistakeholder approach, involving patients, dermatologists, surgeons, the pharmaceutical industry and medical regulators. The study format was a combination of formal presentations, small group work based on nominal group theory and a subsequent online confirmation survey. Results Forty‐one individuals from 13 countries and four continents participated. Nine items were excluded and there was consensus to propose seven domains: disease course, physical signs, HS‐specific quality of life, satisfaction, symptoms, pain and global assessments. Conclusions The HISTORIC consensus meetings I and II will be followed by further e‐Delphi rounds to finalize the core domain set, building on the work of the in‐person consensus meetings
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