Amine gradient process

As mentioned earlier, the COMA positive resists tend to have higher optical absorption at 193 nm than polymethacrylate and COBRA systems, which would produce a tapered image profile. To overcome this potential problem, the T-top formation by absorption of base into the top layer (see above) has been intentionally incorporated in the lithographic process (amine gradient process) [281]. Poly(acrylic acid-co-methyl acrylate) and L-proline were dissolved in water and spin-cast on a COMA resist. During PEB the amine in the overcoat diffuses into the COMA resist layer and compensates for the acid gradient caused by illumination, providing a vertical profile. 

It is possible that antidepressant drugs have other targets in addition to their actions at cell surface monoamine transporters. AI-Damluji and Kopin (107) have described a novel amine uptake process in peptide-containing hypothalamic neurons, which they, named "transport-P." Like the vesicular transporters this process is driven by a proton gradient, but it is distinct from the vesicular transporters in being insensitive to reserpine, but sensitive to a variety of tricyclic antidepressants at micromolar concentrations (108). It is not clear, however, what role if any transport-P plays in the inactivation of the monoamine neurotransmitters. 

Alteration of this epoxy structure is the result of the fact that the epoxy molecules are both reacting and diffusing at the same time. This process forms a concentration gradient with a high epoxy monomer concentration at the surface which gradually reduces to the bulk concentration away from the surface. The properties of an epoxy with an excess of resin can be quite different from the stoichiometric amount. Figure 2, for example, illustrated the alteration of cured epoxy mechanical properties with epoxy/amine ratio. Excess epoxy or less than the stoichiometric amount of amine produces a brittle material if the mixture is cured in the same manner as the stoichiometric amount (Fig. 2). The stoichiometric sample has the lowest modulus while excess amine produces increased brittleness. The potential for variation in local properties within the epoxy due to the presence of a 200 nm or less layer must be considered. 

Noradrenaline is transported by uptake systems that have been extensively studied. On release of noradrenaline from sympathetic nerve varicosities in the peripheral nervous system, it is subject to two uptake systems. Uptake 1 (UJ is a reuptake process where the noradrenaline is recovered by the nerve via a process that has a high affinity but relatively low maximum rate, whereas a second process, uptake 2 (Uj), clears noradrenaline from the tissues into extraneuronal sites by a low affinity, but fast, process (which is inhibited by GLUCOCORTICOIDS, phenoxybenzamine and normetanephrine). The first - the neuronal system - has been studied in detail, and is essentially the same process as used for dopamine and 5-hydroxytryptamine in the CNS. The U transport protein has now been cloned, and is one of a famiiy of transporter proteins which act as co-transporters for Na, Cl and the amine, driven by the ATP-generated electrochemical gradient for Na . This Ui noradrenaline reuptake process is inhibited by cocaine and amphetamine (thus accounting for some of their actions, particularly within the CNS), phenoxybenzamine and the extensive class of tricyclic and related compounds that are used as ANTIDEPRESSANTS (e.g. desipramine). 

Norepinephrine released into the synaptic area is rendered inactive either by O-methylation (primarily meta but some para) via catechol O-methyltransferase (13) or by uptake by the neuronal amine uptake system. Utilizing the inwardly-directed Na+ concentration gradient maintained by the neuronal membrane (Na+ + K+)-ATPase, norepinephrine is co-transported with Na+ in a facilitated diffusion process which appears to be carrier-mediated (14, lip). +... 

A typical gradient application of lonPac CS17 is the analysis of alkanolamines, including mono-, di-, and triethanolamine. Alkanolamines are most commonly used, individually or in combination, to optimize the efficiency of the scrubber treatment for a specific chemical process. The CS17 column resolves all combinations of these scrubber amines using a methanesulfonic acid gradient and elevated column temperature, as illustrated in Figure 4.23. 

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