532 research outputs found

    Metabolomics guides rational development of a simplified cell culture medium for drug screening against <i>Trypanosoma brucei</i>

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    n vitro culture methods underpin many experimental approaches to biology and drug discovery. The modification of established cell culture methods to make them more biologically relevant or to optimize growth is traditionally a laborious task. Emerging metabolomic technology enables the rapid evaluation of intra- and extracellular metabolites and can be applied to the rational development of cell culture media. In this study, untargeted semiquantitative and targeted quantitative metabolomic analyses of fresh and spent media revealed the major nutritional requirements for the growth of bloodstream form &lt;i&gt;Trypanosoma brucei&lt;/i&gt;. The standard culture medium (HMI11) contained unnecessarily high concentrations of 32 nutrients that were subsequently removed to make the concentrations more closely resemble those normally found in blood. Our new medium, Creek's minimal medium (CMM), supports in vitro growth equivalent to that in HMI11 and causes no significant perturbation of metabolite levels for 94% of the detected metabolome (&#60;3-fold change; α = 0.05). Importantly, improved sensitivity was observed for drug activity studies in whole-cell phenotypic screenings and in the metabolomic mode of action assays. Four-hundred-fold 50% inhibitory concentration decreases were observed for pentamidine and methotrexate, suggesting inhibition of activity by nutrients present in HMI11. CMM is suitable for routine cell culture and offers important advantages for metabolomic studies and drug activity screening

    A pilot market test of instant Kona coffee

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    Eddy current probe design for second-layer cracks under installed fasteners

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    The United States Air Force has an operational need to reliably detect second-layer cracks around fastener holes in two-layer airframe structures with the fasteners in place. Because access to the second layer is usually not available, the inspection must be performed by placing a probe on the outer surface of the structure and detecting cracks through the first layer. Eddy current methods have been applied to this inspection problem [1–6], and have met with some success; however, much improvement is still needed to achieve the desired sensitivity to cracks and rejection of signals caused by the geometry of the structure under inspection

    Black hole solutions in the warped DGP braneworld

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    We study the static, analytical solution of black holes in the warped DGP braneworld scenario. We show that the linearized field equations and matching conditions lead to solutions that are not compatible with Schwarzschild-(A)dS(4)_{(4)} solutions on the brane. This incompatibility is similar to vDVZ discontinuity in massive gravity theory. Following the standard procedure to remove this discontinuity, which firstly was proposed by Vainshtein, we keep some appropriate nonlinear terms in the field equations. This strategy has its origin in the fact that the spatial extrinsic curvature of the brane plays a crucial role in the nonlinear nature of the solutions and also in recovering the well-measured predictions of General Relativity (GR) at small scales. Using this feature, we obtained an interesting black string solution in the bulk when it is compatible with 4D GR solutions on the brane.Comment: 15 pages, no figure

    Influence of a Brane Tension on Phantom and Massive Scalar Field Emission

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    We elaborate the signature of the extra dimensions and brane tension in the process of phantom and massive scalar emission in the spacetime of (4+n)-dimensional tense brane black hole. Absorption cross section, luminosity of Hawking radiation and cross section in the low-energy approximation were found. We envisage that parameter connected with the existence of a brane imprints its role in the Hawking radiation of the considered fields.Comment: 7 pages, * figures, RevTex, to be published in General Relativity and Gravitatio

    Model based moving horizon optimal modes-switch schedule in hybrid powertrains for marine applications

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    This is the author accepted manuscriptData availability statement: The research data supporting this publication are provided within this paper.Nowadays, the hybridisation and the electrification of the powertrains for the marine sectors are of paramount importance to reduce their carbon footprints. In this paper, a novel method is proposed to schedule the modes-switch of an hybrid powertrain for marine applications. The considered system is composed of an Internal Combustion Engine mounted in parallel with a Lynch DC Brushed Electric Machine to deliver power at the propeller shaft. The two key-findings of this paper are: i) A compact mathematical representation of the powertrain to model the energy balances and switching of the different modes of operation. ii) A novel graph-inspired approach to determine the optimal operational mode sequence. The objective is to find the modes schedule over a fixed time horizon that minimises both the fuel consumed and the number of modes changes. The solution is motivated by both the moving horizon principle and the shortest path identification algorithm, and it also relies on a predictive information of the power cycle. Numerical simulations are undertaken, showing the benefits of the proposed scheme. The proposed method is convenient to scale up for the integration of additional energy storage components or new modes of operation.Innovative UK Project KTP with Lynch Motor

    Greybody factors in a rotating black-hole background-II : fermions and gauge bosons

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    We study the emission of fermion and gauge boson degrees of freedom on the brane by a rotating higher-dimensional black hole. Using matching techniques, for the near-horizon and far-field regime solutions, we solve analytically the corresponding field equations of motion. From this, we derive analytical results for the absorption probabilities and Hawking radiation emission rates, in the low-energy and low-rotation case, for both species of fields. We produce plots of these, comparing them to existing exact numerical results with very good agreement. We also study the total absorption cross-section and demonstrate that, as in the non-rotating case, it has a different behaviour for fermions and gauge bosons in the low-energy limit, while it follows a universal behaviour -- reaching a constant, spin-independent, asymptotic value -- in the high-energy regime.Comment: 22 pages, 8 figures, added reference

    Benznidazole biotransformation and multiple targets in <i>Trypanosoma</i> cruzi revealed by metabolomics

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    &lt;b&gt;Background&lt;/b&gt;&lt;p&gt;&lt;/p&gt; The first line treatment for Chagas disease, a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, involves administration of benznidazole (Bzn). Bzn is a 2-nitroimidazole pro-drug which requires nitroreduction to become active, although its mode of action is not fully understood. In the present work we used a non-targeted MS-based metabolomics approach to study the metabolic response of T. cruzi to Bzn.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methodology/Principal findings&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Parasites treated with Bzn were minimally altered compared to untreated trypanosomes, although the redox active thiols trypanothione, homotrypanothione and cysteine were significantly diminished in abundance post-treatment. In addition, multiple Bzn-derived metabolites were detected after treatment. These metabolites included reduction products, fragments and covalent adducts of reduced Bzn linked to each of the major low molecular weight thiols: trypanothione, glutathione, Îł-glutamylcysteine, glutathionylspermidine, cysteine and ovothiol A. Bzn products known to be generated in vitro by the unusual trypanosomal nitroreductase, TcNTRI, were found within the parasites, but low molecular weight adducts of glyoxal, a proposed toxic end-product of NTRI Bzn metabolism, were not detected.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions/significance&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Our data is indicative of a major role of the thiol binding capacity of Bzn reduction products in the mechanism of Bzn toxicity against T. cruzi

    Occupational therapy for people with psychotic conditions in community settings: a pilot randomized controlled trial

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    OBJECTIVES: To investigate the effectiveness of a long established intervention, occupational therapy for people with psychotic conditions, and to inform future research designs. DESIGN: A pilot randomized controlled trial. SETTING: Two community mental health teams in a UK city. PARTICIPANTS: Forty-four adults with schizophrenia or other psychotic conditions, and functional problems. INTERVENTIONS: Twelve months of individualized occupational therapy in community settings, as an adjunct to usual care and compared to treatment as usual. A two to one randomization ratio was used in favour of occupational therapy. OUTCOME MEASURES: Social Functioning Scale, Scale for the Assessment of Negative Symptoms and employment. RESULTS: Both groups' scores on Social Functioning Scale and Scale for the Assessment of Negative Symptoms showed significant improvement over 12 months. The Social Functioning Scale overall mean difference for occupational therapy was 2.33, P=0.020 and for treatment as usual was 6.17, P=0.023. The Scale for the Assessment of Negative Symptoms total mean difference for occupational therapy was -16.25, P<0.001 and for treatment as usual was -17.36, P= 0.011. There were no differences between the two groups on any of the outcome measures. After 12 months the occupational therapy group showed clinically significant improvements that were not apparent in the control group. These were in four subscales of the Social Functioning Scale: relationships, independence performance, independence competence and recreation. Out of 30 people receiving occupational therapy those with a clinical level of negative symptoms reduced from 18 (64%) to 13 (46%), P=0.055. CONCLUSION: This pilot study suggested that individualized occupatio
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