Self-nuclei

In those cases where the injection of self-nuclei in every MD is most difficult in view of the very large number of MDs, domain III is split into two domains. Evaluation of the self-nucleation of the PE block within S35E15C50219 shows that not only domain II is absent, but upon decreasing Ts, the PE block is annealed before any detectable self-nucleation occurs (Fig. 17c). Therefore two subdomains were defined [98] domain IIIa, where annealing without previous self-nucleation occurs and domain IIIsa> where self-nucleation and annealing are simultaneously observed for Ts < 88 °C. Domain IIIsa would be the exact equivalent to the standard domain III established by Fillon et al. [75]. 

Various amounts of self-nuclei were produced by heating the samples above the melting point. All self-nuclei are destroyed only above 402 K, and the constant crystalhzation kinetics is established with the remaining foreign nuclei. Table 3.4 contains a hst of the crystallization peak temperatures by DSC on cooling of... 

Self-nucleation is a technique to produce self-seeds or self-nuclei within a polymer melt, so that its nucleation can be greatly enhanced. In principle, the best nucleating agent for any polymer should be its own crystallographically ideal crystal fragments or chain segments with a residual crystal memory [30-33]. 

Eigure 5.25 plots the nucleation efficiency, calculated with Equation 5.6, for melt-mixed blends of PCL and multiwall carbon nanotubes (MWCNT) [241]. The nucleation efficiency rapidly increases with MWCNT content and saturates at values close to 200% efficiency. This means that the MWCNT are being more efficient than self-nuclei in promoting PCL nucleation. 

The CNT nucleafion efficiency for three different nanocomposites employing CNTs is summarized in Figure 5.28. The efficiency calculated with Equation 5.6 yields values above 100% in all cases, indicating that CNTs are much better nucleating agents than the homopolymer self-nuclei. Because of this reason, this nucleating effect has been termed supernucleation. ... 

Muller et al. [119] prepared different nanocomposites in which the interactions between the polymer matrix and the nanofiller have been established to be close. For example, in-situ polymerized high-density polyethylene on CNTs and PCL and PEO covalently bonded to CNTs. In all of these nanocomposites a super-nucleation effect was detected where the CNTs perform a more efficient nucleating action than the self-nuclei of the polymer matrix. It is believed that such a super-nucleation effect stems from the fact that the polymer chains are tethered to the surface of the CNT and can easily form nuclei. 

There are a number of NMR methods available for evaluation of self-diffusion coefficients, all of which use the same basic measurement principle [60]. Namely, they are all based on the application of the spin-echo technique under conditions of either a static or a pulsed magnetic field gradient. Essentially, a spin-echo pulse sequence is applied to a nucleus in the ion of interest while at the same time a constant or pulsed field gradient is applied to the nucleus. The spin echo of this nucleus is then measured and its attenuation due to the diffusion of the nucleus in the field gradient is used to determine its self-diffusion coefficient. The self-diffusion coefficient data for a variety of ionic liquids are given in Table 3.6-6. 

Self-Test 1.9A Calculate the same ratio but for the more distant point at r = 2a0, twice as far from the nucleus. 

Self-Test 17.3A Which of the following processes, (a) electron capture, (b) proton emission, (c) (3 emission, (d) (3+ emission, might a Cd nucleus undergo to begin to reach stability Refer to Figs. 17.13 and 17.15. 

Self-Test 17.3B Which of the set of processes listed in Self-Test 17.3A might a l4 iCe nucleus undergo to begin to reach stability ... 

Self-Tfst 17.7A Calculate the binding energy of a carbon-12 nucleus in electronvolts. 

Use the band of stability to predict the types of decay that a given radioactive nucleus is likely to undergo (Self-Test 17.3). 

The non-enveloped human viruses all have icosahedral capsids. The structural proteins undergo a self-assembly process to form capsids into which the viral nucleic acid is packaged. Most non-enveloped viruses accumulate within the cytoplasm or nucleus and are only released when the cell lyses. 

Initiation of behaviour Mesolimbic pathway to nucleus accumbens from VTA (AIO) Mesocortical pathways to prefrontal cortex from VTA (AIO) Animals Increases locomotor activity and intracranial self-stimulation Humans Hallucinations, psychoses (reward, reinforcement) Animals Decreases activity and self-stimulation Humans Reduces positive symptoms of schizophrenia D2 ... 

Both amphetamine and cocaine have also been reported to support intracranial self-administration in the mesolimbic/mesocortical dopaminergic system. Rats will self-administer cocaine into the medial prefrontal cortex (Goeders and Smith 1983). while amphetamine is self-administered into the orbitofrontal cortex of rhesus monkeys (Phillips and Rolls 1981) and the nucleus accumbens of rats (Hoebel et al. 1983 Monaco et al. 1981). These data indicate that the mesolimbic/mesocortical dopaminergic system is involved in the initiation of stimulant reinforcement processes, and this work suggests that the region of the nucleus accumbens, more specifically the mesolimbic dopamine system, may be an important substrate for reinforcing properties of several psychomotor stimulant drugs. 

The neuroehemical sites for psyehomotor stimulant reward are likely to be the presynaptic dopamine terminals located in the region of the nucleus aeeumbens, frontal cortex, and other forebrain structures that originate in the ventral tegmental area. Note, however, that intraeranial self-administration of eoeaine is elicited from the frontal cortex, but not from the nucleus aeeumbens (Goeders and Smith 1983). Thus, eoneomitant activation of structures other than the nucleus accumbens may be an important part of the circuitry involved in initiation of cocaine intravenous self-administration, as has been hypothesized for the opiates (Smith and Lane 1983 Smith et al. 1982). 

QUESTION Can you get animals to self-administer cocaine into the nucleus accumbens ... 

ANSWER No, I never tried that, but the literature there is complicated, as you know. Animals will, however, self-administer cocaine into the frontal cortex. Amphetamine is self-administered into the nucleus accumbens. 

Monaco, A.P. Hernandez, L. and Hoebel, B.G. Nucleus aeeumbens Site of amphetamine self-injeetion Comparison with the lateral ventriele. In Chronister, R.B., and DeFranee, J.F., eds. The Neurobiology of the Nucleus Accumbens. Brunswiek, ME Haer Institute Press, 1981. pp. 338-342. 

Roberts, D.C. Koob, G.F. Klonoff, P. and Fibiger, H.C. Extinetion and recovery of cocaine self-administration following 6-hydroxydopamine lesions of the nucleus accumbens. Pharmacol Biochem Behav 12 781-787, 1980. 

Rimonabant (382) has also shown promise in pre-clinical and clinical studies as an aid to smoking cessation. (382) decreases nicotine self-administration in rats and nicotine-induced dopamine release in nucleus acumbens [372], and also reversed nicotine-seeking behaviour in rats several weeks... 

For the conduction electrons, it is reasonable to consider that the inner-shell electrons are all localized on individual nuclei, in wave functions very much like those they occupy in the free atoms. The potential V should then include the potential due to the positively charged ions, each consisting of a nucleus plus filled inner shells of electrons, and the self-consistent potential (coulomb plus exchange) of the conduction electrons. However, the potential of an ion core must include the effect of exchange or antisymmetry with the inner-shell or core electrons, which means that the conduction-band wave functions must be orthogonal to the core-electron wave functions. This is the basis of the orthogonalized-plane-wave method, which has been successfully used to calculate band structures for many metals.41... 

Pettit, H.O., Ettenberg, A., Bloom, F.E., and Koob, G.F., Destruction of dopamine in the nucleus accumbens selectively attenuates cocaine but not heroin self-administration in rats, Psychopharmacology, 84, 167, 1984. 

Zito, K.A., Vickers, G., and Roberts, D.C.S., Disruption of cocaine and heroin self-administration following kianic acid lesions of the nucleus accumbens, Pharmacol. Biochem. Behav, 23, 1029, 1985. 

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