Template memory

In order to minimize swelling, MIP is often synthesized in a polar solvent, such as dimethylformamide (DMF) or ACN [113]. Most importantly, a (cross-linker)-to-(functional monomer) mole ratio affects the chemosensor performance. That is, a high (5 1) ratio enhances mechanical strength of an MIP film and favours formation of binding sites. But a low (1 5) ratio leads to a flexible MIP film of improved template memory and stronger adherence to the transducer surface [114]. Therefore, this ratio must be compromised for preparation of MIP of superior performance [114]. 

It is proved, that the bioinoiganic matrix of comparison on gelatin (BP-M Gelatin) possesses opposite selective properties. This matrix has been synthesized without template ions of metal, and it does not possess properties of template memory. 

To prepare artificial enzymatic systems possessing molecular recognition ability for particular molecules, molecular imprinting methods that create template-shaped cavities with the memory of the template molecules in polymer matrices, have been developed [22, 30-35] and established in receptor, chromatographical separations, fine-chemical sensing, etc. in the past decade. The molecular... 

Rutaecarpine (46) is the major alkaloid found in Evodia rutaecarpa (Juss.) Benth., and activities relevant to AD have been identified with the extract and with rutaecarpine. Dehydroevodiamine (47), another alkaloid from the same species, inhibited AChE in vitro, and reversed scopolamine-induced memory impairment in rats and increased cerebral blood flow in vivo in cats, a property which would supplement its usefulness in AD. The structures of (46) and (47) and tacrine (28) have been used as templates for the development of a series of synthetic compounds which have been evaluated for their antiChE activity. These were found to be inhibitory against both AChE and BuChE with A -(2-phenylethyl)-A -[(12Z)-7,8,9,10-tetrahydroazepino [2,l- ]quinazolin-12(6//)-ylidene] amine (48) showing higher affinity for BuChE. 

Lauceri, R., Raudino, A., Scolaro, L. M Mical, N., and Purrello, R. (2002). From achiral porphyrins to template-imprinted chiral aggregates and further self-replication of chiral memory from scratch. / Am. Chem. Soc., 124, 894-5. 

To rapidly recognize and attack and preferably destroy or inactivate a foreign invader, the system has to have a template in its memory derived from an earlier exposure. Consequently, immune reactions require at least two exposures and sometimes more. The first exposure is the sensitization stage, followed by an elicitation stage when a subsequent exposure(s) occurs. Frequently, repeated or long-term exposure is necessary. 

The first reported attempt of using MIPs to control the stereochemical course of a reaction dates back to 1980, when the two research groups of Neckers and Shea published, simultaneously, examples of bulk polymers able to control the formation of the product by using a chiral template. Shea et al. reported that bulk polymers imprinted with stereochemically pure ( )-/ra/w-l,2,cyclobutane-dicarboxyilic acid (6) were able to keep a molecular memory of the asymmetry of the template [8]. In fact, this was transferred to an achiral substrate, such as fumaric acid (7), inducing a diastereoselective methylation, which led to trans-1,2,cyclopropane-dicarboxyilic... 

Nestmate recognition is believed to involve the matching of a label, the so-called colony odor (i.e. the chemical profile containing the nestmate cues), with a template (the neural representation of the colony odor stored in the memory), and depending on the... 

The traditionally accepted model for nestmate recognition of label-template matching involving long-term memory and thus higher integration centers in the brain, has recently... 

Since individuals within the colony are almost constantly encountering their nestmates, it would not be adaptive to continuously have to compare their profiles with an internal template in the long-term memory. The alternative would be to filter out all this input early in the neural structures and only react to hydrocarbon profiles that are dissimilar to the nestmate ones. With either desensitized antennae or habituated antennal lobes, individuals in the social insect colony would not detect or respond to the hydrocarbon profiles of nestmates (D-present), nor would they actively detect that non-nestmate hydrocarbon patterns are absent (U-absent) when accepting an encountered individual, as proposed by Sherman et al. (1997). Instead, they would only detect cues present on non-nestmates, since only these trigger the antennae or the antennal lobe to respond, and on this basis reject the encountered individual. Social insects would thus use the following as a simple rule of thumb if the receptor neurons are not spiking and/or the pattern of activation in the antennal lobes is not altered (no differences in nestmate recognition cues are detected), the encountered individual is accepted as a nestmate. This results in the same acceptance and rejection outcome... 

Fig. 25 Enantioselective non covalent synthesis of double rosettes exploiting the chiral memory effect. Pyridyl residues on the dimelamine units bind chiral dicarboxylic acids leading mainly to one diastereoisomer. Once the chiral templating carboxylic acid is removed by precipitation, the enantioenriched double rosette persists for several hours...

---