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Contact System (contact + system)
Selected AbstractsAllergy-like reactions to iodinated contrast agents.FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 3 2005A critical analysis Abstract Allergy-like reactions may occur following administration of iodinated contrast media (CM), mostly in at-risk patients (patients with history of previous reaction, history of allergy, co-treated with interleukin-2 or beta-blockers, etc.) but remain generally unpredictable. Severe and fatal reactions are very rare events. All categories of CM may induce such reactions, although first generation (high osmolar CM) have been found to induce a higher rate of adverse events than low osmolar CM. However, no differences were found between the two categories of CM with respect to mortality. Delayed reactions can also occur. There are no differences between the various categories of CM except for non-ionic dimers, which are more likely to induce such effect. Numerous clinical studies have evaluated the prophylactic value of drugs (mostly antihistamines and corticosteroids). Results are unclear and highly variable. Any prevention depends upon the mechanism involved. However, the mechanism of CM-induced allergy-like reaction remains disputed. Relatively recent data revived the hypothesis of a type-I hypersensitivity mechanism. Positive skin tests to CM have been reported. However, the affinity of IgE towards CM has been found to be very low in the only study which actually evaluated it. Other pathophysiological mechanisms (involving direct secretory effects on mast cells or basophils, or activation of the complement system associated or not with the plasma contact system) are also much debated. Anaphylaxis and anaphylactoid reactions are, in the end, clinically undistinguishable. [source] A numerically scalable domain decomposition method for the solution of frictionless contact problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2001D. Dureisseix Abstract We present a domain decomposition method with Lagrange multipliers for solving iteratively frictionless contact problems. This method, which is based on the FETI method and therefore is named here the FETI-C method, incorporates a coarse contact system that guides the iterative prediction of the active zone of contact. We demonstrate numerically that this method is numerically scalable with respect to both the problem size and the number of subdomains. Copyright © 2001 John Wiley & Sons, Ltd. [source] Stick-slip in the presence of a normal vibrationLUBRICATION SCIENCE, Issue 3 2002M. Krallis Abstract This paper presents a dynamic analysis of a contact system subjected to an applied normal vibration. The tangential motion of the system is found to exhibit stick-slip behaviour dependent on the applied vibration, even in the absence of a difference in static and kinetic friction or a negative gradient in the friction-velocity relation. The analysis leads to the development of a criterion for stick-slip in the form of an equation defined in terms of the system and input parameters. This criterion is also presented graphically and is assessed through a series of experiments. The analysis and measurements show that stick-slip occurs for a significantly wider drive velocity range when the normal vibration applied is near the natural frequency of the drive system. In addition, when stick-slip occurs in the presence of a normal vibration, the frequency of stick-slip is found to lock in to the frequency of the applied vibration. [source] High speed laser processing for monolithical series connection of silicon thin-film modulesPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2008Stefan Haas Abstract A detailed analysis of the monolithical series connection of silicon thin-film modules with metal back contact fabricated by high-speed laser ablation will be presented. In this study, optically pumped solid-state lasers with wavelengths of 1064,nm and 532,nm were used for the patterning process. The influence of various laser parameters on the performance of amorphous and microcrystalline silicon modules will be discussed. In particular, the line-scribing parameters for a TCO and Ag back contact system was analyzed in detail, since it is the most critical patterning step. A detailed description of the back contact ablation process will be presented and a criterion for flakeless patterning was defined. Finally the influence of the back contact patterning on the electrical behavior of silicon single junction cells was studied. The dark current density versus back-contact patterning line length was analyzed by means of a developed SPICE (simulation program with integrated circuit emphasis) simulation model. Copyright © 2007 John Wiley & Sons, Ltd. [source] Increased activity of plasma and tissue kallikreins, plasma kininase II and salivary kallikrein in pemphigus foliaceus (fogo selvagem)BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2005T.B. Rosatelli Summary Background, Pemphigus foliaceus (PF) is an autoimmune blistering disease of unknown aetiology, which is endemic in Brazil. Although the pathogenesis of PF is still unknown, proteins of the contact system have been implicated. Objectives, As the components of the kinin system may interact with those of the contact system, in this study we evaluated the plasma levels of high-molecular-weight kininogen (HK) and low-molecular-weight kininogen (LK), and the activity of plasma kallikrein, tissue kallikrein and kininase II in plasma of patients with PF presenting with Nikolsky's sign. As kidneys and salivary glands are relevant sources of tissue kallikrein for plasma, we also evaluated urinary/salivary kallikrein and urinary kininase II activities. Methods, Fifteen patients and 15 age- and sex-matched controls were studied. Kininogen levels were determined by enzyme-linked immunosorbent assay, and the activities of kallikreins and kininase II were determined using selective chromogenic substrates. Results, Compared with controls, plasma HK levels were decreased (P = 0·031), whereas the activities of plasma kallikrein, tissue kallikrein and kininase II in plasma, and the activity of salivary kallikrein, were increased in patients (P < 0·001 for each comparison). Plasma levels of LK and the activities of urinary kallikrein and urinary kininase II were not significantly different from controls. Conclusions, Diminished levels of HK associated with increased activities of plasma kallikrein and kininase II indicate that the kinin system is activated at the systemic level in PF. As active plasma kallikreins may act on some proteins of the contact system, it is possible that the enzyme may contribute to blister formation. The further observation of an increased tissue kallikrein activity at the systemic and saliva levels may be interpreted as a systemic reflex of skin inflammation. Whether the activation of the kinin system is a cause or a consequence of blister formation needs further clarification. [source] FFS contact searching algorithm for dynamic finite element analysisINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 7 2001Fujun Wang Abstract A new contact searching algorithm for general contact systems is proposed in this paper. Due to that the smooth and accurate geometry description is crucial to the contact stress analysis, we have worked out a free-formed-surface (FFS) algorithm specialized to model the contacting surface with the C1 boundary continuity and the exact boundary condition definition. Moreover, the geometrical description using the FFS produces those data required for determining the actual contact direction and calculating the exact contact penetration. Numerical simulation results demonstrate that our contact searching algorithm is robust and capable to simulate three-dimensional contact problems accurately. Copyright © 2001 John Wiley & Sons, Ltd. [source] Structure and evolution of low-mass W Ursae Majoris type systems , III.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2005The effects of the spins of the stars ABSTRACT In a previous paper, using Eggleton's stellar evolution code, we have discussed the structure and evolution of low-mass W Ursae Majoris (W UMa) type contact binaries with angular momentum loss owing to gravitational radiation or magnetic braking. We find that gravitational radiation is almost insignificant for cyclic evolution of low-mass W UMa type systems, and it is possible for angular momentum to be lost from W UMa systems in a magnetic stellar wind. The weaker magnetic activity shown by observations in W UMa systems is likely caused by the lower mass of the convective envelopes in these systems than in similar but non-contact binaries. The spin angular momentum cannot be neglected at any time for W UMa type systems, especially for those with extreme mass ratios. The spin angular momenta of both components are included in this paper and they are found to have a significant influence on the cyclic evolution of W UMa systems. We investigate the influence of the energy transfer on the common convective envelopes of both components in detail. We find that the mass of the convective envelope of the primary in contact evolution is slightly more than that in poor thermal contact evolution, and that the mass of the convective envelope of the secondary in contact evolution is much less than that in poor thermal contact evolution. Meanwhile, the rate of angular momentum loss of W UMa type systems is much lower than that of poor thermal contact systems. This is indeed caused by the lower masses of the convective envelopes of the components in W UMa type systems. Although the models with angular momentum loss for W UMa systems exhibit cyclic evolution, they seem to show that a W UMa system cannot continue this type of cyclic evolution indefinitely, and it might coalesce into a fast-rotating star after about 1200 cycles of evolution (about 7.0 × 109 yr). [source] The contact/kinin and complement systems in vasculitisAPMIS, Issue 2009DIANA KARPMAN Vasculitides are a group of conditions with marked inflammation in and around vessel walls and vascular leakage. These conditions may involve the presence of auto-antibodies such as ANCA or may be mediated by other autoimmune or pathogenic mechanisms. Regardless of the primary trigger, vasculitides entail activation of the complement system as well as the contact/kinin system. In vivo and in vitro data support the involvement of these systems showing activation of the alternative, classical and lectin complement pathways as well as release of bradykinin at sites of vascular inflammation. This short review will summarize some of the data regarding the participation of these systems and the interplay between the complement and kinin systems as well as their interaction with the endothelium and neutrophils. Although these systems do not play a primary role in induction of vasculitis, the peptides released contribute to inflammation and vascular leakage and may thus be identified as potential therapeutic targets. [source] | |||||||||||||