Development of a Kinetic Model for Catalytic Reforming of Naphtha and Parameter Estimation Using Industrial Plant Data

In the present paper, a semi-empirical kinetic model for catalytic reforming has been developed. In the developed model, the component “lumping” strategy is based on a paraffins, olefins, naphthalenes, and aromatics (PONA) analysis. “Activation energy lumps” are introduced to take into account different values of activation energies within specific reaction classes. The parameters of the model have been estimated by bench marking with industrial data. Simulation results have been found to be in very close agreement with plant data. One of the advantages of the present kinetic model is that it predicts the concentration of hydrogen and light gases very well. Because it is formulated from basic principles, this kinetic model with some modification can be applied to any catalytic reformer

Activity-dependent modulation of inhibitory synaptic kinetics in the cochlear nucleus

<div>Spherical bushy cells (SBCs) in the anteroventral cochlear nucleus respond to acoustic stimulation with discharges that precisely encode the phase of low-frequency sound. The accuracy of spiking is crucial for sound localization and speech perception. Compared to the auditory nerve input, temporal precision of SBC spiking is improved through the</div><div>engagement of acoustically evoked inhibition. Recently, the inhibition was shown to be less precise than previously understood. It shifts from predominantly glycinergic to synergistic GABA/glycine transmission in an activity-dependent manner. Concurrently, the inhibition attains a tonic character through temporal summation. The present study provides a comprehensive understanding of the mechanisms underlying this slow inhibitory input.</div><div>We performed whole-cell voltage clamp recordings on SBCs from juvenile Mongolian gerbils and recorded evoked inhibitory postsynaptic currents (IPSCs) at physiological rates. The data reveal activity-dependent IPSC kinetics, i.e., the decay is slowed with increased input rates or recruitment. Lowering the release probability yielded faster decay kinetics of the single- and short train-IPSCs at 100 Hz, suggesting that transmitter quantity plays an important role in controlling the decay. Slow transmitter clearance from the synaptic cleft caused prolonged receptor binding and, in the case of glycine, spillover to nearby synapses. The GABAergic component prolonged the decay by contributing to the asynchronous vesicle release depending on the input rate. Hence, the different factors controlling the amount of transmitters in the synapse jointly slow the inhibition during physiologically relevant activity. Taken together, the slow time course is predominantly determined by the receptor kinetics and transmitter clearance during short stimuli, whereas long duration or high frequency stimulation additionally engage asynchronous release to prolong IPSCs.</div><div><br></div><div>[This Document is Protected by copyright and was first published by Frontiers. All rights reserved, it is reproduced with permission.]</div

Benfotiamine Attenuates Inflammatory Response in LPS Stimulated BV-2 Microglia

<div><p>Microglial cells are resident immune cells of the central nervous system (CNS), recognized as key elements in the regulation of neural homeostasis and the response to injury and repair. As excessive activation of microglia may lead to neurodegeneration, therapeutic strategies targeting its inhibition were shown to improve treatment of most neurodegenerative diseases. Benfotiamine is a synthetic vitamin B1 (thiamine) derivate exerting potentially anti-inflammatory effects. Despite the encouraging results regarding benfotiamine potential to alleviate diabetic microangiopathy, neuropathy and other oxidative stress-induced pathological conditions, its activities and cellular mechanisms during microglial activation have yet to be elucidated. In the present study, the anti-inflammatory effects of benfotiamine were investigated in lipopolysaccharide (LPS)-stimulated murine BV-2 microglia. We determined that benfotiamine remodels activated microglia to acquire the shape that is characteristic of non-stimulated BV-2 cells. In addition, benfotiamine significantly decreased production of pro-inflammatory mediators such as inducible form of nitric oxide synthase (iNOS) and NO; cyclooxygenase-2 (COX-2), heat-shock protein 70 (Hsp70), tumor necrosis factor alpha α (TNF-α), interleukin-6 (IL-6), whereas it increased anti-inflammatory interleukin-10 (IL-10) production in LPS stimulated BV-2 microglia. Moreover, benfotiamine suppressed the phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK) and protein kinase B Akt/PKB. Treatment with specific inhibitors revealed that benfotiamine-mediated suppression of NO production was via JNK1/2 and Akt pathway, while the cytokine suppression includes ERK1/2, JNK1/2 and Akt pathways. Finally, the potentially protective effect is mediated by the suppression of translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the nucleus. Therefore, benfotiamine may have therapeutic potential for neurodegenerative diseases by inhibiting inflammatory mediators and enhancing anti-inflammatory factor production in activated microglia.</p></div

The effect of benfotiamine on LPS—induced expression of proinflammatory effector molecules.

<p>(<b>A</b>) Expression of prostaglandin—endoperoxidase synthase 2 (PTGS2) at mRNA level in BV-2 cells. Expression of PTGS2-mRNA was assessed by RT-PCR, in control culture (white bar), LPS-treated culture (black bar) and cultures pre-treated with benfotiamine, 6 h following addition of LPS. PTGS2-mRNA abundance was expressed relative to the abundance of GAPDH-mRNA, as an internal control. (<b>B</b>) Expression of COX-2 at the protein level, determined by Western blot analysis. Bars show Cox-2/β-actin expression ratio relative to control (100%) ± SEM, from <i>n</i> = 3 separate determinations. Significance levels shown inside the graphs: *<i>p</i> < 0.05 control <i>vs</i>. LPS-induced BV-2 cells, # LPS <i>vs</i>. benfotiamine pretreated LPS activated BV-2 cells.</p

Effect of pharmacological inhibitors on iNOS, TNF and IL6 gene expression followed by NO, IL-6 and TNF-α production.

<p>(<b>A, C, E</b>) Expression of iNOS, TNF and IL6 at mRNA level in BV-2 cells. Expression of iNOS, TNF and IL6-mRNA was assessed by RT-PCR, in control culture (white bar), LPS-treated culture (black bar), cultures pre-treated with U0126 (50 μM), SP600125 (20 μM) or LY294002 (20 μM) in presence or absence of benfotiamine (gray bars), 6 h following addition of LPS. iNOS, TNF and IL6-mRNA abundance was expressed relative to the abundance of GAPDH-mRNA, as an internal control. (<b>B, D, F</b>) The cultured supernatants were collected and analyzed for NO using Griess method, or TNF-α and IL6 production with ELISA. The data represent the mean ± SEM (n = 3), *P<0.05 control vs. LPS-induced BV-2 cells, # LPS vs. benfotiamine pretreated LPS activated BV-2 cells.</p

Effect of benfotiamine on cytokines expression and the release by BV-2 cells.

<p>Expression of TNF-α (A, B), IL-6 (C, D) and IL-10 (E, F) was analyzed at mRNA (A, C, E) and protein (B, D, F) level. Abundance of each mRNA transcript was expressed relative to GAPDH as internal control. Release of the cytokines was determined in the culture supernatants by ELISA. Bars represent mean ± SEM from <i>n</i> = 3 separate determinations. Significance levels shown inside the graphs: * - <i>p</i> < 0.05 control <i>vs</i>. LPS-induced BV-2 cells; # — LPS <i>vs</i>. benfotiamine pretreated LPS activated BV-2 cells.</p

List of primers used for Real Time-PCR.

<p>List of primers used for Real Time-PCR.</p

Functional characterization of benfotiamine effects in LPS-stimulated BV-2 microglia.

<p>(<b>A</b>) Real-time monitoring of BV-2 cell viability using xCELLigence RTCA analyzer. Representative graph showing the rate of proliferation in cells incubated in control medium (red line), medium with 1 μg/ml LPS (black line), or cells pretreated with benfotiamine, 50 μM (pink line), 100 μM (blue line) or 250 μM (green line) and then treated with LPS for 24 h. (<b>B</b>) Benfotiamine- induced alterations in cell morphology were analyzed using phase-contrast microscopy (left panels), whereas cell surface area was quantified by Phalloidin /Hoechst fluorescent staining (red/blue) microscopy (right panels), using AxioVisionRel 4.6 software. Insets: cell surface area was measured in five areas (138 × 104 μm²) per each cover-slip (n = 3) per experimental group in three independent experiments. (<b>C</b>) Bars present mean surface areas (± SEM) obtained from data presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0118372#pone.0118372.g001" target="_blank">Fig. 1B</a>. (<b>D</b>) Cell viability was assessed by crystal violet staining and results are displayed as percentage of control ± SEM (n = 3). *P < 0.05 control vs. LPS-induced BV-2 cells, # LPS vs. benfotiamine pretreated LPS activated BV-2 cells. Scale bar: 20 μm.</p

List of primary and secondary antibodies used for immunofluorescence (IF) and western blot (WB).

<p>List of primary and secondary antibodies used for immunofluorescence (IF) and western blot (WB).</p

Effect of benfotiamine on LPS—induced nuclear translocation of NF-κB/p65.

<p>(<b>A</b>) Nuclear translocation of p65/NF-κB subunit was assessed by immunofluorescence labeling against p65 (red) and Hoechst nuclear fluorescence labeling (blue). (<b>B</b>) Nuclear fluorescence intensity of p65 was measured in > 200 hundred cells per experimental group, using ImageJ software and the results were presented in arbitrary units (lower graph). Data were binned (5 AU steps) according to fluorescence intensity and were represented as mean cumulative percentage ± SEM (upper graph). (<b>C</b>) Effect of benfotiamine on LPS—induced translocation of p65 from cytosolic to nuclear compartment was confirmed by Western blotting. Relative p65/β-tubulin abundance is expressed relative to the same abundance in control culture (100%) ± SEM from <i>n</i> = 4 separate determinations. Significance levels shown inside the graphs: * - <i>p</i> < 0.05 control <i>vs</i>. LPS-induced BV-2 cells; # - LPS <i>vs</i>. benfotiamine pretreated LPS activated BV-2 cells. Scale bar: 20 μm.</p