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Short Chain (short + chain)
Terms modified by Short Chain Selected AbstractsOne-Dimensional Plasmon Coupling by Facile Self-Assembly of Gold Nanoparticles into Branched Chain Networks,ADVANCED MATERIALS, Issue 21 2005S. Lin Short chains and complex networks of interconnected Au nanoparticle chains (see Figure) are produced by a simple template-free approach. Optical spectroscopy and computer simulations show that surface plasmons from individual non-contacting nanoparticles are strongly coupled in the resulting 1D superstructures. These chains may provide a unique way to fabricate complex subwavelength optical waveguides. [source] Sulfatide with short fatty acid dominates in astrocytes and neuronsFEBS JOURNAL, Issue 8 2006Giorgis Isaac Glycosphingolipids are located in cell membranes and the brain is especially enriched. We speculated that the subcellular location of glycosphingolipids depends on their fatty acid chain length because their sugar residues are constant, whereas fatty acid chain length can vary within the same molecule. To test this hypothesis we analysed the glycosphingolipid sulfatide, which is highly abundant in myelin and has mostly long fatty acids. We used a negative ion electrospray tandem mass spectrometry precursor ion scan to analyse the molecular species of sulfatide in cultured astrocytes and a mouse model of the human disease metachromatic leukodystrophy. In these arylsulfatase A (ASA)-deficient mice sulfatide accumulates intracellularly in neurons and astrocytes. Immunocytochemistry was also performed on cultured astrocytes and analysed using confocal laser scanning microscopy. Analyses of the molecular species showed that cultured astrocytes contained sulfatide with a predominance of stearic acid (C18), which was located in large intracellular vesicles throughout the cell body and along the processes. The same was seen in ASA-deficient mice, which accumulated a higher proportion (15 mol% compared with 8 mol% in control mice) of sulfatide with stearic acid. We conclude that the major fatty acid composition of sulfatide differs between white and grey matter, with neurons and astrocytes containing mostly short-chain fatty acids with an emphasis on stearic acid. Based on our results, we speculate that the fatty acid chain length of sulfatide might determine its intracellular (short chain) or extracellular (long chain) location and thereby its functions. [source] INULIN MILK BEVERAGES: SENSORY DIFFERENCES IN THICKNESS AND CREAMINESS USING R-INDEX ANALYSIS OF THE RANKING DATAJOURNAL OF SENSORY STUDIES, Issue 4 2007BEATRIZ VILLEGAS ABSTRACT Inulin has interesting functional properties, which are linked to the average degree of polymerization of its chains. The aims of this work were to explore the effect of adding different types of inulin (short chain, native and long chain) on the thickness and creaminess of milk-beverage model systems, and to explore the possibility of using each of the three types of inulin as a fat replacer in skimmed-milk beverages. Sensory ranking data were analyzed using the R-index. For the two lots of samples (whole milk and skimmed milk), all samples with added inulin were perceived as significantly thicker and creamier than the samples without inulin. The fat mimetic capacity of inulin depended not only on the chain length, but also on the concentration of added inulin. In order to obtain milk beverages with reduced fat content having similar thickness and creaminess than those perceived in whole milk beverages, it was necessary to add long-chain inulin at concentrations over 8%. PRACTICAL APPLICATIONS In most cases, inulin is added to different foods to supplement them in order to increase fiber ingestion, in amounts that vary between 3 and 6 g per portion, or to assure its bifidogenic nature, adding 3,8 g per portion. The results of this work provide information regarding the effects of inulin on the sensory characteristics of milk beverages, and show that applying the R-index analysis helped detect the small perceivable differences in thickness and creaminess among the samples tested, what will be of great use in formulating low-fat milk beverages. [source] Dose,response feeding study of short chain chlorinated paraffins (SCCPs) in laying hens: Effects on laying performance and tissue distribution, accumulation and elimination kineticsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 2 2007Karl-Heinz Ueberschär Abstract Technical short chain chlorinated paraffins (C10,C13 with 60% chlorine) were fed to 93 laying hens from 24 to 32 weeks of age in increasing concentrations of up to 100 mg/kg feed. No significant influence on health, relative organ weights or performance (laying intensity, egg weight, feed consumption) was noted. The chlorinated paraffin content of the tissues was linearly related to the concentration of short chain paraffins of the feed. The highest concentrations were found in abdominal fat, egg yolk and fatty tissues. Breast muscle, egg albumen and bile fluid contained minimal or no residues. Less than 1% of the chlorinated paraffins ingested were incorporated into the body (without head, feet, gut and feathers), whereas about 1.5% were eliminated with the egg yolk and 30% were excreted with urine and faeces. A six-week kinetic depuration study revealed a biphasic elimination with half-lifes of 4,40 min (liver, kidneys, legs, fat, blood) for the initial rapid phase, and 15,30 days (blood, fat, liver, yolk, kidneys, legs) for the terminal slow phase. [source] Fatty acid oxidation and meiotic resumption in mouse oocytesMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 9 2009Stephen M. Downs We have examined the potential role of fatty acid oxidation (FAO) in AMP-activated protein kinase (AMPK)-induced meiotic maturation. Etomoxir and malonyl CoA, two inhibitors of carnitine palmitoyl transferase-1 (CPT1), and thus FAO, blocked meiotic induction in dbcAMP-arrested cumulus cell-enclosed oocytes (CEO) and denuded oocytes (DO) by the AMPK activator, AICAR. C75, an activator of CPT1 and FAO, stimulated meiotic resumption in CEO and DO. This effect was insensitive to the AMPK inhibitor, compound C, indicating an action downstream of AMPK. Palmitic acid or carnitine also promoted meiotic resumption in DO in the presence of AICAR. Since C75 also suppresses the activity of fatty acid synthase (FAS), we tested another FAS inhibitor, cerulenin. Cerulenin stimulated maturation in arrested oocytes, but to a lesser extent, exhibited significantly slower kinetics and was effective in CEO but not DO. Moreover, etomoxir completely blocked C75-induced maturation but was ineffective in cerulenin-treated oocytes, suggesting that the meiosis-inducing action of C75 is through activation of FAO within the oocyte, while that of cerulenin is independent of FAO and acts within the cumulus cells. Finally, we determined that long chain, but not short chain, fatty acyl carnitine derivatives were stimulatory to oocyte maturation. Palmitoyl carnitine stimulated maturation in both CEO and DO, with rapid kinetics in DO; this effect was blocked by mercaptoacetate, a downstream inhibitor of FAO. These results indicate that activation of AMPK stimulates meiotic resumption in mouse oocytes by eliminating a block to FAO. Mol. Reprod. Dev. 76: 844,853, 2009. © 2009 Wiley-Liss, Inc. [source] Donor,Acceptor-Substituted Oligo(1,4-phenylene)sHELVETICA CHIMICA ACTA, Issue 6 2009Soungkyoo Kim Abstract Oligo(para -phenylene)s (DAOPPs) 2a,2d (n=1,4) with terminal donor,acceptor substitution (D=C6H13O, A=NO2) were prepared by applying Suzuki cross-couplings for chain extension and end capping. The push,pull effect induces short-reaching polarizations of the chain consisting of conjugated but twisted benzene rings, which was studied by NMR measurements. Electron excitation from the ground-state S0 to the more planar first-excited singlet state S1 is combined with a strong intramolecular charge transfer (ICT), which is documented by the red shift of the long-wavelength absorption (charge-transfer band) for short chains (one or two repeat units, n,=,1 or 2). The opposite influence of decreasing ICT and increasing conjugation length leads to a bathochromic series (,max(n+1),,max(n)) with a fast saturation of ,max (n). The effective conjugation length nECL=4 corresponds to ,, 349,nm. These results are discussed in the context of other oligo(para -phenylene)s (OPPs). [source] Microscopic configurations on the bare-bone surfaces of mammalian synovial jointsINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 6 2001A.E.W. MilesArticle first published online: 30 NOV 200 Abstract The smoothness characteristic of synovial joint surfaces of bare bones is shown to be an illusion; low-power microscopy of young adult human bones from interments revealed, on the surfaces of a variety of synovial joints, a system of basically hemispherical elevations, often united as short chains or groups. This system was also found on joints of a variety of species of six mammalian orders. Under the higher magnification of scanning electron microscopy (SEM), many elevations had a pit at their summits. The bare-bone surfaces of synovial joints have a thin covering of mineralized cartilage, including its mineralizing-front, which survives taphonomic processes, as well as the preparative procedures used in the study of articular surfaces. In its formative phase, the front has the chondrocyte,columnar structure of cartilage. It is postulated here that the newly-discovered elevations arise when cartilage formation is ceasing, or becoming dormant, and that each column-unit produces a globular mineralized mass, often with a pit which had accommodated a chondrocyte. These masses may incorporate the fibre systems of the unmineralized cartilage and aid in its attachment to the bony surface. Copyright © 2001 John Wiley & Sons, Ltd. [source] Modelling disease spread in a novel host: rabies in the European badger Meles melesJOURNAL OF APPLIED ECOLOGY, Issue 6 2002G. C. Smith Summary 1Although the red fox Vulpes vulpes is the main reservoir of rabies in Europe, badger Meles meles populations are known to be drastically affected. Models of badger population dynamics are combined with a fox/rabies model to examine the possibility of rabies spread in high-density badger populations, such as those found in the United Kingdom (UK). 2Although some data exist on rabies epizootiology in the badger, there are no data on badger-to-badger contact rates (either healthy or diseased animals). As a starting point consensus expert opinion was used to devise contact probabilities, and the model was found to be insensitive to reasonable variation in these rates for the density of badgers at which these estimates were made. 3Density-dependent (but not density-independent) contact probabilities simulated short chains of infections that may occur in continental Europe at low badger densities, and simulated true epizootics at higher densities. 4Another possible reason for these short chains of infections in continental Europe is a very high level of fragmentation between social groups. 5Given the high level of territorial contiguity and possible contact rates found in some parts of the UK, the model suggests that rabies is capable of spreading within the UK badger population, and a provisional map showing the likelihood of an epizootic is presented. [source] Characterization of ring-opening polymerization of genipin and pH-dependent cross-linking reactions between chitosan and genipinJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2005Fwu-Long Mi Abstract In this study, a novel chitosan-based polymeric network was synthesized by crosslinking with a naturally occurring crosslinking agent,genipin. The results showed that the crosslinking reactions were pH-dependent. Under basic conditions, genipin underwent a ring-opening polymerization prior to crosslinking with chitosan. The crosslink bridges consisted of polymerized genipin macromers or oligomers (7 , 88 monomer units). This ring-opening polymerization of genipin was initiated by extracting proton from the hydroxyl groups at C-1 of deoxyloganin aglycone, followed by opening the dihydropyran ring to conduct an aldol condensation. At neutral and acidic conditions, genipin reacted with primary amino groups on chitosan to form heterocyclic amines. The heterocyclic amines were further associated to form crosslinked networks with short chains of dimmer, trimer, and tetramer bridges. An accompanied reaction of nucleophilic substitution of the ester group on genipin by the primary amine group on chitosan would occur in the presence of an acid catalysis. The extent in which chitosan gels crosslinked with genipin was significantly dependent on the crosslinking pH values: 39.9 ± 3.8% at pH 5.0, 96.0 ± 1.9% at pH 7.4, 45.4 ± 1.8% at pH 9.0, and 1.4 ± 1.0% at pH 13.6 (n = 5, p < 0.05). Owing to the different crosslinking extents and different chain lengths of crosslink bridges, the genipin-crosslinked chitosan gels showed significant difference in their swelling capability and their resistance against enzymatic hydrolysis, depending on the pH conditions for crosslinking. These results indicated a direct relationship between the mode of crosslinking reaction, and the swelling and enzymatic hydrolysis properties of the genipin-crosslinked chitosan gels. The ring-opening polymerization of genipin and the pH-dependent crosslinking reactions may provide a novel way for the preparation and exploitation of chitosan-based gels for biomedical applications. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1985,2000, 2005 [source] N - n -Alkyl N,N -dimethylammonioacetic acid bromides: the first complete series of crystal and molecular structure determinations of an amphiphilic compound with alkyl chain lengths n = 1,..., 16ACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2000Rainer Rudert The molecular and crystal structures of 16 N - n -alkyl N,N -dimethylammonioacetic acid bromides with chain lengths between n = 1 and n = 16 have been determined. All compounds from n = 5 to n = 16 form bilayers with interdigitated chains. The even-numbered chains display the chain packing type M2II. The chain packing of the odd-numbered chain compounds is less regular. The head groups of all compounds are connected via electrostatic N+,Br, interactions, and by OH,Br, hydrogen bonds. The compounds with short chains are packed in different ways. Their molecular conformation depends on the crystal packing. [source] | ||||||||||||||||