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Several Units (several + unit)
Selected AbstractsDevelopment of a potent and selective GPR7 (NPBW1) agonist: a systematic structure,activity study of neuropeptide BJOURNAL OF PEPTIDE SCIENCE, Issue 6 2007Maki Kanesaka Abstract Neuropeptide B (NPB) has been recently identified as an endogenous ligand for GPR7 (NPBW1) and GPR8 (NPBW2) and has been shown to possess a relatively high selectivity for GPR7. In order to identify useful experimental tools to address physiological roles of GPR7, we synthesized a series of NPB analogs based on modification of an unbrominated form of 23 amino acids with amidated C -terminal, Br(,)NPB-23-NH2. We confirmed that truncation of the N -terminal Trp residue resulted in almost complete loss of the binding affinity of NPB for GPR7 and GPR8, supporting the special importance of this residue for binding. Br(,)NPB-23-NH2 analogs in which each amino acid in positions 4, 5, 7, 8, 9, 10, 12 and 21 was replaced with alanine or glycine exhibited potent binding affinity comparable to the parent peptide. In contrast, replacement of Tyr11 with alanine reduced the binding affinity for both GPR7 and GPR8 four fold. Of particular interest, several NPB analogs in which the consecutive amino acids from Pro4 to Val13 were replaced with several units of 5-aminovaleric acid (Ava) linkers retained their potent affinity for GPR7. Furthermore, these Ava-substituted NPB analogs exhibited potent agonistic activities for GPR7 expressed in HEK293 cells. Among the Ava-substituted NPB analogs, analog 15 (Ava-5) and 17 (Ava-3) exhibited potency comparable to the parent peptide for GPR7 with significantly reduced activity for GPR8, resulting in high selectivity for GPR7. These highly potent and selective NPB analogs may be useful pharmacological tools to investigate the physiological and pharmacological roles of GPR7. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] Synthesis and Fourier transform Raman spectroscopic study of diene-terminated polystyrene oligomersJOURNAL OF RAMAN SPECTROSCOPY, Issue 3 2005N. J. Ward Abstract Polystyrene oligomers capped with a known number of butadiene or isoprene units were synthesized by ,living' anionic polymerization in cyclohexane. The FT-Raman spectra of these compounds show small but significant differences in ,(CC) wavenumber position depending on whether just a single unit or several units of the diene are present at the chain end. However, if the butadiene experiments are repeated under polar-modified conditions, so that 1,2- rather than 1,4-addition takes place, the ,(CC) Raman band position is found to be independent of the number of ,out-of-chain' vinyl double bonds which are present. This conclusion is explained in terms of the mass change on diene addition to the polymer chains. Application of the method for the quantitation of polymer chain-end diene termination is proposed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Design and application of a membrane bioreactor unit to upgrade and enhance the required performance of an installed wastewater treatment plantASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2010Teresa Castelo-Grande Abstract Wastewater treatment plants (WWTPs) are nowadays common solutions to improve the quality of streams and soils. However, there are still many issues required to be solved within these plants. We were commissioned to redesign a WWTP in Amarante, Portugal, which was not working properly. Among the several units we have designed, there is a membrane bioreactor representing one of the main units of this remodelled WWTP. The biological treatment stage at the upgraded WWTP will take place in the remodelled primary and secondary settlers and in the remodelled and improved biological reactor. Hence, the primary settler is readapted in such a way that it functions as the anoxic area of the biological treatment, while the aerobic treatment will be sequentially performed at the remodelled biological reactor and at the actual secondary settler. Membrane treatment will be performed by using ultrafiltration membranes. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Cephalopod chromatophores: neurobiology and natural historyBIOLOGICAL REVIEWS, Issue 4 2001J. B. MESSENGER ABSTRACT The chromatophores of cephalopods differ fundamentally from those of other animals: they are neuromuscular organs rather than cells and are not controlled hormonally. They constitute a unique motor system that operates upon the environment without applying any force to it. Each chromatophore organ comprises an elastic sacculus containing pigment, to which is attached a set of obliquely striated radial muscles, each with its nerves and glia. When excited the muscles contract, expanding the chromatophore; when they relax, energy stored in the elastic sacculus retracts it. The physiology and pharmacology of the chromatophore nerves and muscles of loliginid squids are discussed in detail. Attention is drawn to the multiple innervation of dorsal mantle chromatophores, of crucial importance in pattern generation. The size and density of the chromatophores varies according to habit and lifestyle. Differently coloured chromatophores are distributed precisely with respect to each other, and to reflecting structures beneath them. Some of the rules for establishing this exact arrangement have been elucidated by ontogenetic studies. The chromatophores are not innervated uniformly: specific nerve fibres innervate groups of chromatophores within the fixed, morphological array, producing ,physiological units' expressed as visible ,chromatomotor fields'. The chromatophores are controlled by a set of lobes in the brain organized hierarchically. At the highest level, the optic lobes, acting largely on visual information, select specific motor programmes (i.e. body patterns); at the lowest level, motoneurons in the chromatophore lobes execute the programmes, their activity or inactivity producing the patterning seen in the skin. In Octopus vulgaris there are over half a million neurons in the chromatophore lobes, and receptors for all the classical neurotransmitters are present, different transmitters being used to activate (or inhibit) the different colour classes of chromatophore motoneurons. A detailed understanding of the way in which the brain controls body patterning still eludes us: the entire system apparently operates without feedback, visual or proprioceptive. The gross appearance of a cephalopod is termed its body pattern. This comprises a number of components, made up of several units, which in turn contains many elements: the chromatophores themselves and also reflecting cells and skin muscles. Neural control of the chromatophores enables a cephalopod to change its appearance almost instantaneously, a key feature in some escape behaviours and during agonistic signalling. Equally important, it also enables them to generate the discrete patterns so essential for camouflage or for signalling. The primary function of the chromatophores is camouflage. They are used to match the brightness of the background and to produce components that help the animal achieve general resemblance to the substrate or break up the body's outline. Because the chromatophores are neurally controlled an individual can, at any moment, select and exhibit one particular body pattern out of many. Such rapid neural polymorphism (,polyphenism') may hinder search-image formation by predators. Another function of the chromatophores is communication. Intraspecific signalling is well documented in several inshore species, and interspecific signalling, using ancient, highly conserved patterns, is also widespread. Neurally controlled chromatophores lend themselves supremely well to communication, allowing rapid, finely graded and bilateral signalling. [source] | ||||||||||