477 research outputs found

    Synthetic Melatonin Receptor Agonists and Antagonists

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    The functions of the pineal hormone melatonin are of intense and continuous interest. Synthetic melatonin receptor analogues, as agonists and antagonists, have been explored, and the molecule can be viewed as consisting of an indole nucleus, acting mainly as a spacer, and the C5-OMe and the C3-ethylamido side chains, acting as pharmacophoric components. The present chapter focuses on the synthetic routes towards these melatonin derivatives, first the aromatic nucleus, then the functionalities that have been introduced to the nucleus, and finally those analogues with restrained conformations and those that are optically active. The importance of the various parameters involved in the agonist and antagonist profile of the compounds is indicated, as is the difference in the action of the chiral melatoninergics

    Synthesis and evaluation of novel 2,4-disubstituted arylthiazoles against T. brucei.

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    The design, synthesis and pharmacological evaluation of the 4-substituted-2-[3-(adamant-1-yl)-4-fluorophenyl]thiazoles 1a-j, the 4-substituted-2-[4-(adamant-1-yl)phenyl]thiazoles 2a-h, the 2-substituted-4-[4-(adamant-1-yl)phenyl]thiazoles 3a-e, the N-substituted 2-phenylthiazol-4-ethylamides 4a, b and the N-substituted 4-phenylthiazol-2-ethylamides 4c, d is described. Compounds 1a and 2a exhibit trypanocidal activity in the range of IC50 = 0.42 ÎĽM and IC50 = 0.80 ÎĽM, respectively. Both of these derivatives bear a lipophilic end, which consists of a 4-(1-adamantyl) phenyl or a 3-(1-adamantyl)phenyl moiety, a 1,3-thiazole ring and a functional end, which comprises of an alkylamine and can be considered as promising candidates for the treatment of Trypanosoma brucei infections

    A modification of the convective constraint release mechanism in the molecular stress function model giving enhanced vortex growth

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    The molecular stress function model with convective constraint release (MSF with CCR) constitutive model [J. Rheol. 45 (2001), 1387] is capable of fitting all viscometric data for IUPAC LDPE, with only two adjustable parameters (with difference found only on reported Âżsteady-stateÂż elongational viscosities). The full MSF with CCR model is implemented in a backwards particle-tracking implementation, using an adaptive method for the computation of relative stretch that reduces simulation time many-fold, with insignificant loss of accuracy. The model is shown to give improved results over earlier versions of the MSF (without CCR) when compared to well-known experimental data from White and Kondo [J. non-Newt. Fluid Mech., 3 (1977), 41]; but still to under-predict contraction flow opening angles. The discrepancy is traced to the interaction between the rotational dissipative function and the large stretch levels caused by the contraction flow. A modified combination of dissipative functions in the constraint release mechanism is proposed, which aims to reduce this interaction to allow greater strain hardening in a mixed flow. The modified constraint release mechanism is shown to fit viscometric rheological data equally well, but to give opening angles in the complex contraction flow that are much closer to the experimental data from White and Kondo. It is shown (we believe for the first time) that a constitutive model demonstrates an accurate fit to all planar elongational, uniaxial elongational and shear viscometric data, with a simultaneous agreement with this well-known experimental opening angle data. The sensitivity of results to inaccuracies caused by representing the components of the deformation gradient tensor to finite precision is examined; results are found to be insensitive to even large reductions in the precision used for the representation of components. It is shown that two models that give identical response in elongational flow, and a very similar fit to available shear data, give significantly different results in flows containing a mix of deformation modes. The implication for constitutive models is that evaluation against mixed deformation mode flow data is desirable in addition to evaluation against viscometric measurements

    Electronic recording of lifetime locomotory activity patterns of adult medflies.

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    Age-specific and diurnal patterns of locomotory activity, can be considered as biomarkers of aging in model organisms and vary across the lifetime of individuals. Τhe Mediterranean fruit fly (medfly), Ceratitis capitata, is a commonly used model-species in studies regarding demography and aging. In the present study, we introduce a modification of the automated locomotory activity electronic device LAM25system (Locomotory Activity Monitor)-Trikinetics, commonly used in short time studies, to record the daily locomotory activity patterns of adult medflies throughout the life. Additionally, fecundity rates and survival of adult medflies were recorded. Male and female medflies were kept in the system tubes and had access to an agar-based gel diet, which provided water and nutrients. The locomotory activity was recorded at every minute by three monitors in the electronic device. The locomotory activity of females was higher than that of males across the different ages. For both sexes locomotory rates were high during the first 20 days of the adult life and decreased in older ages. The activity of males was high in the morning and late afternoon hours, while that of females was constantly high throughout the photophase. Negligible locomotory activity was recorded for both sexes during the nighttime. Males outlived females. Fecundity of females was higher in younger ages. Our results support the adoption of LAM25system in studies addressing aging of insects using medfly as a model organism

    High precision fundamental constants at the TeV scale

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    This report summarizes the proceedings of the 2014 Mainz Institute for Theoretical Physics (MITP) scientific program on "High precision fundamental constants at the TeV scale". The two outstanding parameters in the Standard Model dealt with during the MITP scientific program are the strong coupling constant αs\alpha_s and the top-quark mass mtm_t. Lacking knowledge on the value of those fundamental constants is often the limiting factor in the accuracy of theoretical predictions. The current status on αs\alpha_s and mtm_t has been reviewed and directions for future research have been identified.Comment: 57 pages, 24 figures, pdflate

    Coordinated oncogenic transformation and inhibition of host immune responses by the PAX3-FKHR fusion oncoprotein

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    Tumors have evolved elaborate mechanisms for evading immune detection, such as production of immunoinhibitory cytokines and down-regulation of major histocompatibility complex (MHC) expression. We have studied PAX3-FKHR as an example of an oncogenic fusion protein associated with an aggressive metastatic cancer. We show that PAX3-FKHR alters expression of genes that are normally regulated by Janus kinase/signal transducer and activator of transcription (STAT) signaling pathways. This occurs as a result of a specific interaction between PAX3-FKHR and the STAT3 transcription factor, which results in a dramatic reduction in tumor MHC expression, and an alteration in local cytokine concentrations to inhibit surrounding inflammatory cells and immune detection. Collectively, these data show that an oncogenic transcription factor can promote tumor growth and tissue invasion while inhibiting local inflammatory and immune responses. This is the first time that an immunomodulatory role has been described for an oncogenic fusion protein
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