First-generation

If the molecules could be detected with 100% efficiency, the fluxes quoted above would lead to impressive detected signal levels. The first generation of reactive scattering experiments concentrated on reactions of alkali atoms, since surface ionization on a hot-wire detector is extremely efficient. Such detectors have been superseded by the universal mass spectrometer detector. For electron-bombardment ionization, the rate of fonnation of the molecular ions can be written as... 

One option is to first generate two random numbers and 2 between 0 and 1. T1 corresponding two numbers from the normal distribution are then calculated using... 

To obtain this matrix by the multivariate method, we first generate two absorptivity vectors ap and a2j from a known concentration matrix in parts per million... 

UOP s Isomar process (56,117—119) was originally developed to use dual-functional catalysts. The first-generation catalyst contained Pt and halogen on alumina. Operating conditions using this catalyst were 399°C 1.25 MPa 2 LHSV and H2/hydrocarbon ratio of 6 1. A Cg naphthene concentration of... 

In summary, these second-generation gasifiers offer promise for the future in terms of increased efficiency as weU as for use of other feedstocks, such as biomass. The older, first-generation gasifiers, however, continue to be used. 

Atopic Dermatitis. The mechanism of itching associated with atopic dermatitis remains unknown, but histamine is almost certainly involved to some extent as histamine concentrations are increased in the skin and in the plasma of patients with this disorder (39,42). Second-generation H receptor antagonists, unlike first-generation H receptor antagonists, have not been uniformly found to be effective in relieving itching in atopic dermatitis, which may be related to the absence of a sedative effect (43). 

Methoprene and hydroprene are first-generation juvenoids that iacorporate minor stmctural optimisation of neotenin to increase persistence. Methoprene, 1-isopropyl (E,E)-ll-methoxy-3,7,ll-tnmethyl dodecadi-2,4-enoate (129) (bp 100 C/6.7 Pa, vp 3.5 mPa at 25°C), is soluble ia water to 1.4 mg/L. The rat oral LD q is >34,000 mg/kg. Methoprene has been used as a mosquito larvicide, ia baits for ant control, and as a catde feed-through treatment for horn fly control. Hydroprene, methyl (H,H)-3,7,ll-trimethyl-dodecadi-2,4-enoate (130) (bp 174°C at 2.5 kPa, vp 2.5 mPa at 25°C), is soluble ia water to 0.54 mg/L. The rat oral LD q is >34,000 mg/kg. Hydroprene is especially effective against aphids and cockroaches. 

Sulfonylureas. The hypoglycemic effect of sulfonylureas was first noted in the early 1940s when several patients died in hypoglycemic coma after testing glyprothia2ole, a synthetic sulfonamide used to treat typhoid. Chemical modifications which enhanced activity and lowered toxicity led to the development of the first-generation sulfonylureas. Carbutamide [339-43-5] the first commercial sulfonylurea, came onto the European... 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

First generation Second generation Third generation... 

Treatment of Major Depression. Dmgs commonly used for the treatment of depressive disorders can be classified heuristicaHy iato two main categories first-generation antidepressants with the tricycHc antidepressants (TCAs) and the irreversible, nonselective monoamine—oxidase (MAO) inhibitors, and second-generation antidepressants with the atypical antidepressants, the reversible inhibitors of monoamine—oxidase A (RIMAs), and the selective serotonin reuptake inhibitors (SSRIs). Table 4 fists the available antidepressants. 

Second-Generation Antidepressants. The frequency of adverse effects associated with first-generation antidepressants and the lack of patient compliance arising from such adverse effects led to the development of a number of second-generation antidepressants. 

The second-generation antidepressants, particularly RIMAs and SSRJs, are much less toxic ia overdose than the older TCAs and irreversible MAO inhibitors. However, similar to first-generation antidepressants, the therapeutic effect only becomes manifest after several weeks. Up to one-third of depressed patients are nonresponders. Ideally, an antidepressant would combine a more rapid onset of action with greater clinical efficacy and a higher responder rate, as well as even better tolerability. 

RTV Silicone Chemistry. There are two basic cure chemistries used by RTV sihcones the acetoxy-based and the alkoxy-based cure systems. Acetoxy-based RTV sihcones were first commercialized in the early 1960s (422,423). The general chemical reactions of these first-generation products are shown in Figure 8. 

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