First-generation profiles

As with the structural shapes of first-generation profiles (see Section 9.8.1), which mimic the geometry of structural steel cross-sections, so the current practice of bolting FRP structural elements copies the constructive details of steel construction (Fig. 9.4). In most cases, this direct knowledge transfer of connection technology leads to oversized FRP components, since it does not consider the different behavioms of the two materials. In fact, the linear-elastic behaviour of FRP profiles is incompatible with plastic deformations and so the stress concentrations aronnd the bolt holes are higher than those... 

Until quite recently, the structural shapes of pultruded profiles have been copied from steel construction, usually reproducing thin-walled open (I, H, L, C) or tubular (square, rectangular, circular) cross-sections. Figure 9.8 shows the most typical shapes of the so-called first-generation profiles, which are normally composed of glass fibres embedded in polyester or vinylester based resin matrix - GFRP pultruded profiles. 

Typical shapes of the first-generation profiles (courtesy of Fiberline). 

The Hi-antagonists are classified as either first- or second-generation compounds. Second-generation antihistamines have lipophilicity and ionization profiles that make them less able to cross the blood-brain barrier thus they produce dramatically less sedation than do the first-generation drugs. 

Neuroleptics have been the group of drugs most widely recommended for delusional states. Of the first-generation neuroleptics, the sedative, cognitive impairing and extrapyramidal side effects are likely to be particularly prominent in the elderly. The introduction of the atypical neuroleptics should improve the treatment of these disorders as they are generally better tolerated due to their improved side-effect profile. 

Figure 11.12 The dotted lines are generated from the model of cortisol kinetics using the same parameter values as for Fig. 11.10. The solid lines correspond to the same set of parameter values applying a change only in one of them k0 (A), c(0) (B), and observation sampling (D). In (C), the second-day profile is compared to the first-day profile.

A common drawback of all currently known NNRTIs is the fast emergence of drug-resistant mutant HIV-1 [9,10]. Nevirapine is a first generation inhibitor. Unfortunately it is highly sensitive to single point mutations of HIV-RT. The more recent compoimds (second generation inhibitors) have a better resistance profile against mutation [5j. 

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