The Experts below are selected from a list of 97812 Experts worldwide ranked by ideXlab platform
Jennifer L. Gommerman - One of the best experts on this subject based on the ideXlab platform.
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The Regulation of Immune Responses by DC Derived Type I IFN.
Frontiers in immunology, 2013Co-Authors: Jennifer L. GommermanAbstract:Our immune system bears the tremendous task of mounting effective anti-microbial responses whilst maintaining immunoregulatory functions to avoid autoimmunity. In order to quickly respond to pathogens, Dendritic cells (DC) are armed with pattern recognition receptors (PRRs), allowing them to recognize highly conserved pathogen-associated molecular patterns (PAMPs) that are uniquely expressed by invading microbes. PRR activation can trigger DCs to release the pleiotropic cytokine, Type I IFN, which facilitates various biological functions in different immune cell Types. In this review, we will discuss the classical PRR-induced Type I IFN response in DCs as well as describe a novel mechanism for Type I IFN induction by the Tumor-Necrosis Factor receptor superfamily (TNFRSF) members, TNFR-1 and Lymphotoxin-β receptor (LTβR). While PRR activation during viral infection, produces large amounts of Type I IFN in a relative short period of time, TNFRSF-induced Type I IFN expression is modest with gradual Kinetics. Type I IFN can exert pro-inflammatory effects, but in some cases it also facilitates immune-regulatory functions. Therefore, DCs are important regulators of immune responses by carefully modulating Type I IFN expression.
Michael J. Chappell - One of the best experts on this subject based on the ideXlab platform.
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Structural identifiability ofmmodels characterizing saturable binding: Comparison of pseudo-steady-state and non-pseudo-steady-state model formulations
Mathematical biosciences, 1996Co-Authors: Michael J. ChappellAbstract:A two-state variable model in which saturable binding takes place is studied. Two mathematical representations of the same model are considered, one a standard chemical Kinetics Type of polynomial system, the other a reduced model formed from the original system via a pseudo-steady-state approximation. For a particular experiment the structural identifiability of the set of unknown parameters of each model is examined using the similarity transformation approach. The analysis shows that when the pseudo-steady-state approximation is made a certain degree of structural identifiability is lost in the sense that fewer individual parameters can be uniquely identified.
José Luis Capelo - One of the best experts on this subject based on the ideXlab platform.
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Unravelling the role of ultrasonic energy in the enhancement of enzymatic Kinetics
Journal of Molecular Catalysis B-enzymatic, 2011Co-Authors: M. Galesio, Joana Lourenço, Diana Madeira, Mário Diniz, José Luis CapeloAbstract:Abstract The enzymatic hydrolysis of anabolic androgenic steroids excreted to urine as glucuronide conjugates has been recently reported to be improved by applying ultrasonic energy to the reaction medium. The hydrolysis time using β-glucuronidase from Escherichia coli K12 was reduced by a factor of six when ultrasonic energy was employed to enhance the enzymatic kinetic. In this study, the effect of ultrasonic energy on the enzymatic hydrolysis kinetic parameters, as well as on the enzymatic activity of β-glucuronidase from E. coli K12 was assessed. The study was conducted using the compounds 4-nitrophenyl-β- d -glucuronide and 4-nitrophenol. Experimental data suggested that the reaction follows the Michaelis–Menten Kinetics Type. In addition it was found that the ultrasonic energy affects the initial velocity of reaction, which is higher when ultrasound waves are employed when compared to the classical method of incubation at 55 °C. Moreover the values of V max and k cat are higher for the ultrasonic essay ( V max(US) = 17.1 ± 0.8 μM min −1 ; k cat(US) = 340,523 min −1 ; V max(55 °C) = 14.8 ± 0.7 μM min −1 ; k cat(55 °C) = 295,187 min −1 ) whilst the Michaelis–Menten constant obtained for the two methodologies showed similar values ( K M(US) = 94.7 ± 7.2 μM; K M(55 °C) = 92.5 ± 6.6 μM). Deactivation of the enzyme was also observed under ultrasonic energy, which was found particularly evident for experimental conditions with excess of substrate; enzymatic activity half-life time increased with the increase of the E/S ratio. This research work seems to support the idea that the use of ultrasonic energy affects the transition state of the enzymatic reaction and that mass transfer processes are also most likely enhanced.
K. K. Salam - One of the best experts on this subject based on the ideXlab platform.
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Modelling the Kinetics of Microbiologically Influenced Corrosion of Mild Steel in Soil Environments
Thammasat International Journal of Science and Technology, 2016Co-Authors: S. E. Agarry, K. K. SalamAbstract:The objective of this study was to investigate the microbiologically induced corrosion of mild steel in soil by analyzing the physico-chemical and biological characteristics of the soil environment. Soil from three different locations (Lagos, Port Harcourt and Ogbomoso) was used for the study. Weight loss method, microstructure examination and Fourier transform infrared (FTIR) analysis were used for the investigation. The results of the physicochemical and biological characteristics showed that the levels of measured parameters in soil samples are consistent with the conditions in an environment that promotes and sustain microbiologically influenced corrosion. The weight loss method showed that the mild steel suffered from general corrosion. The microstructure examination showed that the presence of biofilm on the surface of the mild steel coupon (MSC) caused pitting corrosion while FTIR depicted the presence of extracellular polymeric substances in the biofilms capable of inducing corrosion. The corrosion data of MSC in the soil environment were analyzed by first order kinetic model and Monod form of kinetic model (Types A and B), respectively. The kinetic models fitted very well to the corrosion data; however, the Monod form of Kinetics (Type B) gave the best correlation ( = 0.9978, 0.9839 and 0.9993) with a maximum specific corrosion rate of 0.893, 0.734 and 0.640 mils per year for MSC buried in Lagos, Port Harcourt and Ogbomoso soil, respectively.
H. Gleiter - One of the best experts on this subject based on the ideXlab platform.
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Diffusion of boron in nanocrystalline iron A new Type of diffusion Kinetics: Type C′
Philosophical Magazine Letters, 1993Co-Authors: H. J. Höfler, Robert S Averback, H. GleiterAbstract:Abstract Measurements of the diffusivity of boron in nanocrystalline iron are presented. It is shown that boron diffuses slower in the grain boundaries than in the lattice. The diffusion data are analysed in terms of a new Type of diffusion Kinetics, Type C′. In Type C′ Kinetics, the diffuser is confined to the grain boundaries by a large segregation factor. Therefore, even though the lattice diffusion is faster than the grain-boundary diffusion, the grain-boundary diffusion coefficient is readily accessible.
