Limitations of charge efficiency in capacitive deionization processes III: The behavior of surface oxidized activated carbon electrodes

In previous papers we reported on attempts to improve the performance of water desalination using capacitive de-ionization (CDI) processes by understanding the ions transport and adsorption/desorption behavior of activated carbon electrodes as a function of the applied potential. We also investigated the charge efficiency in CDI processes of brackish water in symmetrical cells containing identical highly porous activated carbon electrodes. In this work, we study the influence of oxygen-containing surface groups on activated carbon electrodes on the adsorption/desorption behavior of ions in brackish water. A special methodology was developed in order to estimate the charge efficiency of CDI processes which include the ability to prepare various kinds of activated carbon electrodes (ACEs) with controlled porosity and surface groups, measuring the PZC (potential of zero charge) of ACE in solutions and simultaneous adsorption and desorption of ions into/from them. The presence of polar, oxygen containing surface groups on ACE does not affect the electroadsorption behavior of Na⁺ and Cl⁻ ions into porous carbons whose average pore size is greater than 0.58 nm, apart of considerably changing the PZC. This results in a shift of the entire curves of ion adsorption vs. potential. The possible use of ACE with oxidized surfaces in CDI processes is discussed.     

RNA-binding protein conserved in both microtubule- and microfilament-based RNA localization

IL-12 is a key cytokine in the development of Th1 responses. IL-12 production by antigen-presenting cells (APC) can be induced by the interaction between CD40 on the APC and CD40 ligand (CD40L) expressed on T cells after activation. Our previous study indicated that in dendritic cells (DC), the only APC that can activate naive T(h) cells efficiently, the mere CD40 engagement is insufficient to induce IL-12 production. The aim of the present study was to dissect the conditions for efficient IL-12 production by DC further. Using populations of naive and memory Th cells, recombinant CD40L, neutralizing and blocking antibodies, and by determining IFN-gamma production and CD40L expression levels, we here show that T cell-induced IL-12 production by DC results from the action of two signals, mediated by CD40L and IFN-gamma, and that the inability of naive T(h) cells to induce IL-12 production resides in their inability to produce IFN-(gamma). Other factors than CD40L and IFN-gamma can provide the required signals for IL-12 production by DC, as either factor could be replaced by lipopolysaccharide (LPS). The two-signal requirement proved unique for the production of IL-12, since either CD40 engagement or LPS was sufficient for the efficient production of tumor necrosis factor-alpha, IL-8 and the p40 subunit of IL-12, and may be considered as a safety mechanism for optimal control of potentially harmful T(h)1 responses.     

Constant-Power Bit Loading for Multicarrier Systems: BER-Allocation

Adaptive bit loading algorithms are proposed for multi-channel systems in general, and orthogonal frequency division multiplexing in particular. A discrete coding-modulation adaptation is considered. Constant power allocation is assumed for all subchannels, while the bit error rate on different subchannels is unconstrained. The proposed algorithms are computationally efficient and require limited amount of feedback resources. Their performance compare favorably with other practical schemes known in the art.     

Non-linear QFT synthesis by local linearization

Existing non-linear quantitive feedback theory (QFT) techniques are based on some form of linearization of the non-linear plant, where the quality of the controller is a function of the equivalent linearized plant. We propose a new approach to non-linear QFT, based on local linearization of the non-linear plant about closed-loop acceptable outputs. Here, acceptable outputs appear as uncertain parameters in an equivalent linear family, being a generalization of the more traditional linearization about equilibrium points. In some applications, this technique may give better results and is an alternative when the other existing techniques fail. A comparison of this technique to previous ones using an uncertain Van der Pol plant considered previously in the QFT literature, and a pH control system, is presented.     

Dynamic memory processes in retrieving answers to questions: Recall failures, judgments of knowing, and acquisition of information.

Three experiments were conducted to show that engaging in an effort to answer a question markedly influences the processing of information subsequently encountered in the environment. On each of 2 successive days, participants were given a definition test that involved the recall of rare English words cued by their definitions. A lexical-decision task was administered between the 2 definition tests; the timing of the lexical-decision task varied across experiments. A strong target-to-definition priming effect occurred such that prior exposure to words during the lexical-decision task increased their likelihood of being recalled in the final definition test. It also appears that earlier attempts to answer questions affected the acquisition of relevant new material in long-term memory. The role of these priming effects is discussed with respect to the process of updating memory representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stress-activated protein kinases are negatively regulated by cell density

Stimulation by UV irradiation, TNFalpha, as well as PDGF or EGF activates the JNK/SAPK signalling pathway in mouse fibroblasts. This results in the phosphorylation of the N-terminal domain of c-Jun, increasing its transactivation potency. Using an antibody that specifically recognizes c-Jun phosphorylated at Ser63, we show that culture confluency drastically inhibited c-Jun N-terminal phosphorylation due to the inhibition of the JNK/SAPK pathway. Transfection experiments demonstrate that the inhibition occurs at the same level as, or upstream of, the small G-proteins cdc42 and Rac1. In contrast, the classical MAPK pathway was insensitive to confluency. The inhibition of JNK/SAPK activation depended on the integrity of the actin microfilament network. These results were confirmed and extended in monolayer wounding experiments. After PDGF, EGF or UV stimulation, c-Jun was predominantly phosphorylated in cells bordering the wound, which are the cells that move to occupy the wounded area. Thus, modulation of the stress-dependent signal cascade by confluency will restrict c-Jun N-terminal phosphorylation in response to mitogenic or chemotactic agents to cells that border a wounded area.