2,717 research outputs found
Mycotoxins nivalenol and deoxynivalenol differently modulate cytokine mRNA expression in Jurkat T cells.
Deoxynivalenol (DON) and its hydroxylated form nivalenol (NIV) are Fusarium mycotoxins that occur in cereal grains alone or in
combination. Several studies have shown that these metabolites affect lymphocyte functions. However, the molecular mechanisms
underlying their activities are still partially known. To address this issue, we examined the influence of NIV and DON in modulating
IFNc, IL-2 and IL-8 mRNA levels in Jurkat T cells. In PMA/ionomycin stimulated cells, pre-incubated with increasing concentrations of NIV, transcription was induced in the range 0.06â2 lM; higher concentrations of NIV were found non-stimulating (4 lM) or inhibitory (8 lM) for IFNc and IL-2 whereas IL-8 was still induced. DON administration elicited a similar profile for IL-8 and IFNc, whilst IL-2 mRNA was induced in a broader range of concentrations. Combination of NIV and DON at 1:1 and 1:10 ratios essentially restored the cytokine transcriptional pattern observed with NIV alone but the level of transcripts, with the exception of IL-8, peaked at lower concentrations suggesting interactive effects. Moreover both mycotoxins caused inhibition of cell proliferation, mediated by induction of apoptosis, confirming previous results and highlighting the usefulness of Jurkat as a T-cell model to study the effects of mycotoxins on the immune functions in humans
Black and blue: A metaphoric criticism
First, the purpose of this study is to investigate the ways in which blues lyrics apply rhetorical invention, specifically metaphor. Analysis of a sample of songs from the Blues Hall of Fame first explores how classical rhetorical devices are utilized in blues lyrics; Secondly, through metaphoric criticism the unique idiom of the blues reveals a strong trend towards self-abasement. And finally, despite intensified racial awareness of genre of folk (blues) music it is not a closed communicative act, but through the utilization of archetypal metaphor, a universal one
Thermodynamic and Experimental Analysis of a Biomass Steam Power Plant: Critical Issues and their Possible Solutions with CCGT Systemsâ
Abstract This paper shows the experimental and numerical analysis of a biomass steam power plant from maximum power of 2.3 MW with a maximum pressure of 48 bar and a turbine inlet temperature of about 430 °C at the design point. The analysis has been conducted using experimental data, collected directly on the power plant, at the design point, and they have been afterwards used to validate a thermodynamic model. The analysis of the biomass power plant pointed out some critical issues that can be summarized in three points: low plant efficiency due to the small size, biomass supply range and continuous variation of the operating point. In order to solve this problem, different plant configurations were numerically evaluated. The first solution to these problems consists of a 100 kWe micro gas turbine (MGT) fueled by natural gas, whose exhaust gas were sent to the steam generator of the biomass power plant in order to evaluate the benefits on the power fluctuations and on global electric efficiency. A thermodynamic model of the MGT has been developed and validated with experimental data from technical literature, creating a CCGT (Combined Cycle Gas Turbine) system. The analysis of the results of this system showed improvement in terms of efficiency and operational stability. The second option was to fuel the previously validated method of MGT with four different alternative fuels and to evaluate the integration with the biomass plant for all of them. Furthermore, to emphasize the benefits of this integration, the power of the micro turbine has been increased assuming the use of more MGT at the same time. These analyses show an increase of the system efficiency, it could been also used the biomass, not suitable for direct combustion (high humidity), to produce biogas that fuels the MGT, reducing the range of biomass supply
A survey of cherry leaf roll virus in intensively managed grafted english (Persian) walnut trees in Italy
Blackline disease, caused by Cherry leaf roll virus (CLRV), is considered a serious threat limiting English walnut (Juglans regia) production in Italy and the EU if walnut species other than J. regia e.g. \u2018Paradox\u2019 hybrid (J. regia
7 J. hindsii), French hybrid (J. regia
7 J. major or J. regia
7 J. nigra) or northern California black walnut (J. hindsii) are used as the rootstock. The virus transmissibility by pollen as well as latent infections can result in the spread of CLRVcontaminated propagative material, which is a major means of the virus dispersal by human activities. In 2014 and 2015 to ascertain the presence and the distribution of blackline symptoms in commercial orchards and to provide a description of the symptomatology, visual inspections and double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) analyses were carried out on 1,684 walnut trees in four different intensively managed grafted English walnut orchards in northeast Italy (Veneto Region). Trees with clear blackline symptoms at the scion-rootstock junction, often associated with general decline of the plant, were found only in one commercial orchard in northeast Italy on trees older than ten years of cvs. \u2018Tulare\u2019 and \u2018Chandler\u2019, grafted onto \u2018Paradox\u2019 rootstock. To our knowledge this is the first report of CLRV (blackline) decline and death in a commercial walnut orchard in Italy
Solution to the Problem of a Mass Traveling on a Taut String via Integral Equation
The problem of a massive taut string, traveled by a heavy point mass, moving with an assigned law, is formulated in a linear context. Displacements are assumed to be transverse, and the dynamic tension is neglected. The equations governing the moving boundary problem are derived via a variational principle, in which the geometric compatibility between the point mass and the string is enforced via a Lagrange multiplier, having the meaning of transverse reactive force. The equations are rearranged in the form of a unique Volterra integral equation in the reactive force, which is solved numerically. A classical Galerkin solution is implemented for comparison. Numerical results throw light on the physics of the phenomenon and confirm the effectiveness of the algorithm
Perturbation methods for bifurcation analysis from multiple nonresonant complex eigenvalues
It is shown that the logical bases of the static perturbation method, which is currently used in static bifurcation analysis, can also be applied to dynamic bifurcations. A two-time version of the LindstedtâPoincare Ì Method and the Multiple Scale Method are employed to analyze a bifurcation problem of codimension two. It is found that the Multiple Scale Method furnishes, in a straightforward way, amplitude modulation equations equal to normal form equations available in literature. With a remarkable computational improvement, the description of the central manifold is avoided. The LindstedtâPoincare Ì Method can also be employed if only steady-state solutions have to be determined. An application is illustrated for a mechanical system subjected to aerodynamic excitation
A transfer-matrix perturbation approach to the dynamics of chains of nonlinear sliding beams
Chains of nonlinear shear indeformable beams with distributed mass, resting on movable supports, are considered. To determine the dynamic response of the system, the transfer matrix approach is merged with the harmonic balance method and a perturbation method, thereby transforming the original space-temporal continuous problem into a discrete one-dimensional map x_k+1=Fx_k expressed in terms of the state variables x_k at the interface between adjacent beams. Such transformation does not imply any discretization, because it is obtained by integrating the single-element field equations. The state variables consist of both first-order variables, namely, transversal displacement and couples, and second-order variables, which are longitudinal displacement and axial forces. Therefore, while the linear problem is monocoupled, the nonlinear one becomes multicoupled. The procedure is applied to determine frequency-response relationship under free and forced vibrations
A Continuum Approach to the Nonlinear In-Plane Galloping of Shallow Flexible Cables
The aeroelastic stability of horizontal, suspended, shallow, iced cables is studied via a continuum model. Both external and internal damping, consistent with the Rayleigh model, are taken into account. The quasi-static theory of the aerodynamic forces is applied. An in-plane nonlinear model of galloping is formulated, displaying the importance of internal damping, both on the critical velocity and on the limit-cycle amplitude. A perturbation procedure is developed for nonlinear analysis in nonresonant conditions (monomodal galloping). The modification of the galloping mode due to quadratic nonlinearities is studied, and its real or complex character is discussed
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