Selective catalytic reduction (SCR) is a promising diesel after treatment technology that enables low nitrogen oxides (NO x) tailpipe emissions with relatively low fuel consumption. Future emission legislation is pushing the boundaries for SCR control systems to achieve high NO x conversion within a tailpipe ammonia (NH 3) slip constraint, and to provide robustness to meet in-use compliance requirements. This work presents a new adaptive control strategy that uses an ammonia feedback sensor and an online ammonia storage model. Experimental validation on a 12-liter heavy-duty diesel engine with a 34-liter Zeolite SCR catalyst shows good performance and robustness against urea under- and over-dosage for both the European steady-state and transient test cycles. The new strategy is compared with a NO x sensor-based control strategy with cross-sensitivity compensation. It proved to be superior in terms of transient adaptation and taking an NH 3 slip constraint into account.

In order to obtain an in vitro model of human T cell unresponsiveness induced by soluble anti-CD3 mAb in the presence of accessory cells, T cells purified from peripheral blood of healthy volunteers were cultured for 4 days with irradiated accessory cells and OKT3. After a 48 h resting period allowing TCR-CD3 complex re-expression, T cells were rechallenged with plastic-immobilized OKT3, and their proliferative response as well as their secretion of IL-2, IFN-gamma and IL-10 measured. Primary culture with OKT3 induced a state of unresponsiveness characterized by defective responses to OKT3 rechallenge but normal or enhanced responses to PMA and A23187 calcium ionophore, indicating a defect in the early steps of TCR-CD3-mediated signal transduction. Indeed, we found that unresponsive T cells displayed an impaired mobilization of intracellular calcium stores upon TCR-CD3 ligation. In order to determine whether the development of unresponsiveness depends on the initial T cell activation triggered by OKT3, we compared several versions of OKT3 differing in their ability to bind Pc receptors. We found that only the activating antibodies that bind Pc receptors on accessory cells induced T cell unresponsiveness. We conclude that human resting T cells can be rendered unresponsive by anti-CDS mAb in soluble form provided that they trigger T cell activation.

The capacity regions are determined for various communication situations in which one or both encoders for a multiple access channel crib from the other encoder and learn the channel input(s) emitted or to be emitted by this encoder. Most of the achievability proofs herein hinge upon the new concept of backward decoding. Also, the notion of Shannon strategies seems to be of crucial importance. It is demonstrated that in some situations parts of the total cooperation line are achievable. Moreover, it is proved that if the encoders and the decoder are allowed to be nondeterministic, the capacity regions are not increased