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Distribution Analysis (distribution + analysis)
Selected AbstractsPromoter-wide analysis of Smad4 binding sites in human epithelial cellsCANCER SCIENCE, Issue 11 2009Daizo Koinuma Smad4, the common partner Smad, is a key molecule in transforming growth factor-, (TGF-,) family signaling. Loss of Smad4 expression is found in several types of cancer, including pancreatic cancer and colon cancer, and is related to carcinogenesis. Here we identified Smad4 binding sites in the promoter regions of over 25 500 known genes by chromatin immunoprecipitation on a microarray (ChIP-chip) in HaCaT human keratinocytes. We identified 925 significant Smad4 binding sites. Approximately half of the identified sites overlapped the binding regions of Smad2 and Smad3 (Smad2/3, receptor-regulated Smads in TGF-, signaling), while the rest of the regions appeared dominantly occupied by Smad4 even when a different identification threshold for Smad2/3 binding regions was used. Distribution analysis showed that Smad4 was found in the regions relatively distant from the transcription start sites, while Smad2/3 binding regions were more often present near the transcription start sites. Motif analysis also revealed that activator protein 1 (AP-1) sites were especially enriched in the sites common to Smad2/3 and Smad4 binding regions. In contrast, GC-rich motifs were enriched in Smad4-dominant binding regions. We further determined putative target genes of Smad4 whose expression was regulated by TGF-,. Our findings revealed some general characteristics of Smad4 binding regions, and provide resources for examining the role of Smad4 in epithelial cells and cancer pathogenesis. (Cancer Sci 2009) [source] Characterizing anthropic sediments in north European Neolithic settlements: An assessment from Skara Brae, OrkneyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 3 2006Ian A. Simpson The creation of anthropic sediments, traditionally referred to under the blanket term midden, through the utilization of settlement waste materials in domestic settlement construction was first recognized during early excavations at the Orcadian Neolithic site of Skara Brae (V.G. Childe, 1931a; 1931b). Prior to the present study there has been no systematic attempt to identify the nature of these sediments at Skara Brae, whose likely occupation dates between ,3100 and 2500 B.C., or to assess whether different materials were incorporated into construction or varied with different phases of site formation. The opportunity to begin addressing these issues arose with the location of undisturbed sediment samples held in storage since the last site excavations of 1972,1973 (D.V. Clarke, 1976). Ten thin sections were manufactured from these samples, representing earlier and later phases of Neolithic settlement at Skara Brae. Observations using thin-section micromorphology, supported by total phosphorus and particle-size distribution analyses, suggest that both earlier and later settlement phases show accumulation of household waste dominated by fuel residues. These wastes may have been used to help stabilize wind-blown sand deposits during the later settlement phases. In addition, the use of clay material tempered with household waste is associated with wall construction. Animal manures are only evident in anthropic deposits on the edge of the main settlement site where composting may have been taking place, and there is no evidence for their use in site construction. The authors conclude by drawing attention to possible diverse uses of anthropic sediments in settlement construction at other Neolithic settlements in Orkney. © 2006 Wiley Periodicals, Inc. [source] Phylogeography of the introduced species Rattus rattus in the western Indian Ocean, with special emphasis on the colonization history of MadagascarJOURNAL OF BIOGEOGRAPHY, Issue 3 2010Charlotte Tollenaere Abstract Aim, To describe the phylogeographic patterns of the black rat, Rattus rattus, from islands in the western Indian Ocean where the species has been introduced (Madagascar and the neighbouring islands of Réunion, Mayotte and Grande Comore), in comparison with the postulated source area (India). Location, Western Indian Ocean: India, Arabian Peninsula, East Africa and the islands of Madagascar, Réunion, Grande Comore and Mayotte. Methods, Mitochondrial DNA (cytochrome b, tRNA and D-loop, 1762 bp) was sequenced for 71 individuals from 11 countries in the western Indian Ocean. A partial D-loop (419 bp) was also sequenced for eight populations from Madagascar (97 individuals), which were analysed in addition to six previously published populations from southern Madagascar. Results, Haplotypes from India and the Arabian Peninsula occupied a basal position in the phylogenetic tree, whereas those from islands were distributed in different monophyletic clusters: Madagascar grouped with Mayotte, while Réunion and Grand Comore were present in two other separate groups. The only exception was one individual from Madagascar (out of 190) carrying a haplotype that clustered with those from Réunion and South Africa. ,Isolation with migration' simulations favoured a model with no recurrent migration between Oman and Madagascar. Mismatch distribution analyses dated the expansion of Malagasy populations on a time-scale compatible with human colonization history. Higher haplotype diversity and older expansion times were found on the east coast of Madagascar compared with the central highlands. Main conclusions, Phylogeographic patterns supported the hypothesis of human-mediated colonization of R. rattus from source populations in either the native area (India) or anciently colonized regions (the Arabian Peninsula) to islands of the western Indian Ocean. Despite their proximity, each island has a distinct colonization history. Independent colonization events may have occurred simultaneously in Madagascar and Grande Comore, whereas Mayotte would have been colonized from Madagascar. Réunion was colonized independently, presumably from Europe. Malagasy populations may have originated from a single successful colonization event, followed by rapid expansion, first in coastal zones and then in the central highlands. The congruence of the observed phylogeographic pattern with human colonization events and pathways supports the potential relevance of the black rat in tracing human history. [source] Molecular simulation of ammonia absorption in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N])AICHE JOURNAL, Issue 9 2009Wei Shi Isotherms for ammonia absorption in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) are computed at temperatures ranging from 298 K to 348 K using osmotic ensemble Monte Carlo simulations. The results agree well with previous experimental measurements. Activity coefficients vary from 0.5 to 0.8, indicating negative deviations from Raoult's Law. The computed enthalpy of mixing ranges from ,2 to ,11 kJ/mol. Computed partial molar volumes are on the order of 25,30 cm3/mol. Energy and radial distribution analyses indicate that ammonia interacts more strongly with the cation than the anion, in contrast to observations made of other gases in ionic liquids such as CO2. The reason for this behavior is that ammonia forms a strong hydrogen bond with the ring hydrogen atoms of the cation. The simulations predict that strategies aimed at changing the solubility of ammonia should focus on altering the hydrogen bond donating ability of the cation, and that altering the anion will have more modest effects. It is shown that this hypothesis is consistent with available experimental data. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Population structure and history of southern African scrub hares, Lepus saxatilisJOURNAL OF ZOOLOGY, Issue 2 2004U. Kryger Abstract Genetic differentiation among populations of the South African scrub hare Lepus saxatilis was examined using hypervariable mitochondrial DNA control region I (CR-I) sequences. Neighbour-joining analysis revealed a pattern that did not correspond to the current subspecies delineations. The CR-I sequence data delimit scrub hares into three major maternal lineages. The three phylogenetic assemblages exhibited different geographical distributions. AMOVA analyses and exact tests for population differentiation confirmed this phylogeographic partitioning. One lineage (SW) was confined to the south-western Cape, the second lineage (N) was exclusively found in the northern part of South Africa and in the neighbouring countries, and the third lineage (C) was predominant in the central parts of South Africa. This spatial distribution did not coincide with the ranges of the 10 described subspecies covered by our sampling regime. The lineages C and N overlapped in an area including eastern parts of South Africa and southern Namibia. The presence of both lineages in that area of overlap was interpreted as the result of secondary contact due to recent range expansions after the two lineages had undergone a population restriction approximately 18 000 years ago. Analyses of contemporary gene flow disclosed an exchange of migrants between N and C, which was biased towards a movement from C to N. The SW group represents a very distinct evolutionary lineage that has been isolated for more than 45 000 years. It does not exchange female migrants with the other two groups. Mismatch distribution analyses indicated sudden population size expansions in the history of all three populations. [source] mtDNA perspective of chromosomal diversification and hybridization in Peters' tent-making bat (Uroderma bilobatum: Phyllostomidae)MOLECULAR ECOLOGY, Issue 11 2003Federico G. Hoffmann Abstract We compared sequence variation in the complete mitochondrial cytochrome -b gene with chromosomal and geographical variation for specimens of Peters' tent-making bat (Uroderma bilobatum). Three different chromosomal races have been described in this species: a 2n = 42 race from South America east of the Andes, a 2n = 44 from NW Central America and 2n = 38 from the rest of Central America and NW South America. The deepest nodes in the tree were found within the South American race (42 race), which is consistent with a longer history of this race. Average distance among races ranged from 2.5 to 2.9%, with the highest amount of intraracial variation found within the 2n = 42 race (1.7%), intermediate values within the 2n = 38 race (0.9%) and lowest within the 2n = 44 race (0.5%). Variation among chromosomal races accounted for over 55% of molecular variance, whereas variation among populations within races accounted for 6%. The 2n = 38 and 2n = 44 races hybridize in the coastal lowlands of Honduras, near the Gulf of Fonseca. Introgression between these two races is low (two introgressed individuals in 45 examined). Clinal variation across the hybrid zone for the cytochrome -b of U. bilobatum, is similar to clinal variation reported for chromosomes and isozymes of this species. Mismatch distribution analyses suggests that geographical isolation and karyological changes have interplayed in a synergistic fashion. Fixation of the alternative chromosomal rearrangements in geographical isolation and secondary contact is the most likely mechanism accounting for the hybrid zone between the 2n = 38 and 2n = 44 races. If a molecular clock is assumed, with rates ranging from 2.3 to 5.0% per million years, then isolation between these races occurred within the last million years, implying a relatively recent origin of the extant diversity in Uroderma bilobatum. None the less, the three chromosomal races probably represent three different biological species. [source] Improved proteome coverage by using high efficiency cysteinyl peptide enrichment: The human mammary epithelial cell proteomePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2005Tao Liu Abstract Automated multidimensional capillary liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been increasingly applied in various large scale proteome profiling efforts. However, comprehensive global proteome analysis remains technically challenging due to issues associated with sample complexity and dynamic range of protein abundances, which is particularly apparent in mammalian biological systems. We report here the application of a high efficiency cysteinyl peptide enrichment (CPE) approach to the global proteome analysis of human mammary epithelial cells (HMECs) which significantly improved both sequence coverage of protein identifications and the overall proteome coverage. The cysteinyl peptides were specifically enriched by using a thiol-specific covalent resin, fractionated by strong cation exchange chromatography, and subsequently analyzed by reversed-phase capillary LC-MS/MS. An HMEC tryptic digest without CPE was also fractionated and analyzed under the same conditions for comparison. The combined analyses of HMEC tryptic digests with and without CPE resulted in a total of 14,416 confidently identified peptides covering 4294 different proteins with an estimated 10%,gene coverage of the human genome. By using the high efficiency CPE, an additional 1096 relatively low abundance proteins were identified, resulting in 34.3% increase in proteome coverage; 1390,proteins were observed with increased sequence coverage. Comparative protein distribution analyses revealed that the CPE method is not biased with regard to protein Mr,, pI, cellular location, or biological functions. These results demonstrate that the use of the CPE approach provides improved efficiency in comprehensive proteome-wide analyses of highly complex mammalian biological systems. [source] Macrocyclic Cyclo[n]malonates , Synthetic Aspects and Observation of Columnar Arrangements by X-ray CrystallographyEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2006Nikos Chronakis Abstract A variety of achiral and chiral macrocyclic oligomalonates were synthesised in a one-step procedure through condensation of malonyl dichloride with ,,,-diols. We have investigated the applicability of this method by varying the length and type of the spacers in the diol. Product distribution analysis revealed that the preferential formation of monomeric, dimeric, or trimeric macrocyclic malonates can be controlled by choosing diols with specific spacers connecting the hydroxy groups. Of special interest are the macrocyclic bismalonates, as they show pronounced crystallisability and arrange into columnar motifs in the solid state. They feature distinctive dihedral angles: all ester moieties adopt anti conformations whereas the planes of the carboxy moieties of each malonate residue arrange in an approximately orthogonal fashion. The latter geometry is enforced by the macrocyclic structures, as revealed by a conformational search in the Cambridge Structural Database. The X-ray diffraction data show that C=O···H,C, and C,O···H,C hydrogen bonds stabilise the columnar arrangement of the dimeric rings with formation of tubular assemblies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Non-homologous DNA end joining in the mature rat brainJOURNAL OF NEUROCHEMISTRY, Issue 6 2002Keqin Ren Abstract Recent evidence suggests that DNA double strand breaks (DSBs) are introduced in neurons during the course of normal development, and that repair of such DSBs is essential for neuronal survival. Here we describe a non-homologous DNA end joining (NHEJ) system in the adult rat brain that may be used to repair DNA DSBs. In the brain NHEJ system, blunt DNA ends are joined with lower efficiency than cohesive or non-matching protruding ends. Moreover, brain NHEJ is blocked by DNA ligase inhibitors or by dATP and can occur in the presence or absence of exogenously added ATP. Comparison of NHEJ activities in several tissues showed that brain and testis share similar mechanisms for DNA end joining, whereas the activity in thymus seems to utilize different mechanisms than in the nervous system. The developmental profile of brain NHEJ showed increasing levels of activity after birth, peaking at postnatal day 12 and then gradually decreasing along with age. Brain distribution analysis in adult animals showed that NHEJ activity is differentially distributed among different regions. We suggest that the DNA NHEJ system may be utilized in the postnatal brain for the repair of DNA double strand breaks introduced within the genome in the postnatal brain. [source] Physical characteristics and aerosolization performance of insulin dry powders for inhalation prepared by a spray drying methodJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 7 2007Yu You The objective of this study was to investigate the influence of formulation excipients on the physical characteristics and aerosolization performance of insulin dry powders for inhalation. Insulin dry powders were prepared by a spray drying technique using excipients such as sugars (trehalose, lactose and dextran), mannitol and amino acids (L-leucine, glycine and threonine). High performance liquid chromatography and the mouse blood glucose method were used for determination of the insulin content. The powder properties were determined and compared by scanning electron microscopy, thermo-gravimetric analysis and size distribution analysis by a time-of-flight technique. The in-vitro aerosolization behaviour of the powders was assessed with an Aerolizer inhaler using a twin-stage impinger. Powder yield and moisture absorption were also determined. Results showed that there was no noticeable change in insulin content in any of the formulations by both assay methods. All powders were highly wrinkled, with median aerodynamic diameters of 2,4 ,m, and consequently suitable for pulmonary administration. The tapped density was reduced dramatically when glycine was added. The powders containing mannitol, with or without L-Ieucine, were less sensitive to moisture. The highest respirable fraction of 67.3 ± 1.3% was obtained with the formulation containing L-leucine, in contrast to formulations containing glycine and threonine, which had a respirable fraction of 11.2 ± 3.9% and 23.5 ± 2.5%, respectively. In addition, powders with good physical properties were achieved by the combination of insulin and trehalose. This study suggests that L-leucine could be used to enhance the aerosolization behaviour of the insulin dry powders for inhalation, and trehalose could potentially be used as an excipient in the formulations. [source] Genetic Diversity of Cryphonectria hypovirus 1 in China, Japan and ItalyJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2007F.-X. Liu Abstract The aim of this study was to examine the origin of Cryphonectria hypovirus 1 (CHV1) which infects chestnut blight fungus, Cryphonectria parasitica. The genetic diversity of 39 CHV1 isolates from China, Japan and Italy was assessed by combining sequencing and restriction fragment length polymorphic (RFLP) experiments. Based on their partial sequences, 26 CHV1 isolates within 26 haplotypes were grouped into three subtypes. The 17 viruses from China were distributed between subtypes I and III, while all four of the isolates from Japan were subtype II. Of the five isolates from Italy, four were subtype I, and one (IT 192) was subtype III. Our analysis of the geographic distribution of the isolates indicated that all but one of the Chinese subtype III CHV1s are present in northern China; meanwhile all but three of the Chinese subtype I CHV1s are present in South China. Unlike in Europe where there is one predominant CHV1 subtype, our distribution analysis indicates that there has been gene flow between the populations in Asia. Cluster analysis based on the RFLP banding patterns showed that the viral isolates could be separated into four clusters. Most of the viral isolates (29 of 39, 74.4%) were grouped into one large cluster. Greater genetic diversity was observed among the CHV1s from China than among those from Japan and Italy. The Italian isolates were genetically more similar to the Japanese and South Chinese isolates than to the North Chinese isolates, indicating that CHV1 in Italy may have originated from Japan and/or South China. [source] Preparation and characterization of poly(butylene terephthalate)/poly(ethylene terephthalate) copolymers via solid-state and melt polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2007M. A. G. Jansen Abstract To increase the Tg in combination with a retained crystallization rate, bis(2-hydroxyethyl)terephthalate (BHET) was incorporated into poly(butylene terephthalate) (PBT) via solid-state copolymerization (SSP). The incorporated BHET fraction depends on the miscibility of BHET in the amorphous phase of PBT prior to SSP. DSC measurements showed that BHET is only partially miscible. During SSP, the miscible BHET fraction reacts via transesterification reactions with the mobile amorphous PBT segments. The immiscible BHET fraction reacts by self-condensation, resulting in the formation of poly(ethylene terephthalate) (PET) homopolymer. 1H-NMR sequence distribution analysis showed that self-condensation of BHET proceeded faster than the transesterification with PBT. SAXS measurements showed an increase in the long period with increasing fraction BHET present in the mixtures used for SSP followed by a decrease due to the formation of small PET crystals. DSC confirmed the presence of separate PET crystals. Furthermore, the incorporation of BHET via SSP resulted in PBT-PET copolymers with an increased Tg compared to PBT. However, these copolymers showed a poorer crystallization behavior. The modified copolymer chain segments are apparently fully miscible with the unmodified PBT chains in the molten state. Consequently, the crystal growth process is retarded resulting in a decreased crystallization rate and crystallinity. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 882,899, 2007. [source] Emulsifying properties of gum kondagogu (Cochlospermum gossypium), a natural biopolymerJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2009Ganga Modi Naidu Vegi Abstract BACKGROUND: Natural polymers are widely used as emulsifying agents in the food and pharmaceutical industries because of their low cost, biocompatibility and non-toxic nature. In the present study, emulsifying properties of the novel natural biopolymer gum kondagogu (GKG) were investigated. GKG solutions of different concentrations (0.1,0.6% w/v) were prepared in water and emulsified with liquid paraffin oil (40% v/v) in a high-speed homogeniser. Flow properties of the emulsions were measured using a rheometer. Emulsion stability and droplet size distribution were determined by visual observation, photomicrography and laser-scattering particle size distribution analysis. RESULTS: The emulsions prepared with GKG showed pseudoplastic behaviour. The size of oil droplets and the viscosity of emulsions at concentrations of 0.4,0.6% w/v showed little change over time (up to 30 days), indicating that the emulsions were stable. Measurements of the zeta potential of emulsions adjusted to different pH, with and without added electrolyte, showed that the stabilisation of emulsions with GKG was due to mutual repulsion between electrical double layers of particles and adsorption of macromolecules on oil droplets. CONCLUSION: The results of this experimental investigation show that GKG is a good emulsifying agent even at low concentrations, with many potential applications in the food and pharmaceutical industries. Copyright © 2009 Society of Chemical Industry [source] Chloroplast microsatellites reveal colonization and metapopulation dynamics in the Canary Island pineMOLECULAR ECOLOGY, Issue 10 2006MIGUEL NAVASCUÉS Abstract Chloroplast microsatellites are becoming increasingly popular markers for population genetic studies in plants, but there has been little focus on their potential for demographic inference. In this work the utility of chloroplast microsatellites for the study of population expansions was explored. First, we investigated the power of mismatch distribution analysis and the FS test with coalescent simulations of different demographic scenarios. We then applied these methods to empirical data obtained for the Canary Island pine (Pinus canariensis). The results of the simulations showed that chloroplast microsatellites are sensitive to sudden population growth. The power of the FS test and accuracy of demographic parameter estimates, such as the time of expansion, were reduced proportionally to the level of homoplasy within the data. The analysis of Canary Island pine chloroplast microsatellite data indicated population expansions for almost all sample localities. Demographic expansions at the island level can be explained by the colonization of the archipelago by the pine, while population expansions of different ages in different localities within an island could be the result of local extinctions and recolonization dynamics. Comparable mitochondrial DNA sequence data from a parasite of P. canariensis, the weevil Brachyderes rugatus, supports this scenario, suggesting a key role for volcanism in the evolution of pine forest communities in the Canary Islands. [source] Estimating gluconeogenesis by NMR isotopomer distribution analysis of [13C]bicarbonate and [1- 13C]lactateNMR IN BIOMEDICINE, Issue 4 2008Tiago Cardoso Alves Abstract The gluconeogenic contribution to glucose production in livers isolated from rats fasted for 24,h was determined by 13C-NMR isotopomer distribution analysis of secreted glucose enriched from 99% [13C]bicarbonate (n,=,4) and 99% [1- 13C]lactate (n,=,4). Experiments with 3% 2H2O were also performed, allowing the gluconeogenic contribution to be measured by the relative 2H enrichments at positions 5 and 2 of glucose. From 13C-NMR analyses, the contribution of gluconeogenesis to glucose output was estimated to be 93,±,3% for [13C]bicarbonate perfusion and 91,±,3% for [1- 13C]lactate perfusion, in good agreement with the 2H-NMR analysis of the gluconeogenic contribution to glucose production (100,±,1% and 99,±,1%, respectively) and consistent with the expected negligible contribution from glycogenolysis. These results indicate that 13C-NMR analysis of glucose 13C-isotopomer distribution from either [13C]bicarbonate or [1- 13C]lactate precursor provides realistic estimates of the gluconeogenic contribution to hepatic glucose output. Copyright © 2007 John Wiley & Sons, Ltd. [source] Measurement of Lens Protein Aggregation in Vivo Using Dynamic Light Scattering in a Guinea Pig/UVA Model for Nuclear CataractPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2008M. Francis Simpanya The role of UVA radiation in the formation of human nuclear cataract is not well understood. We have previously shown that exposing guinea pigs for 5 months to a chronic low level of UVA light produces increased lens nuclear light scattering and elevated levels of protein disulfide. Here we have used the technique of dynamic light scattering (DLS) to investigate lens protein aggregation in vivo in the guinea pig/UVA model. DLS size distribution analysis conducted at the same location in the lens nucleus of control and UVA-irradiated animals showed a 28% reduction in intensity of small diameter proteins in experimental lenses compared with controls (P < 0.05). In addition, large diameter proteins in UVA-exposed lens nuclei increased five-fold in intensity compared to controls (P < 0.05). The UVA-induced increase in apparent size of lens nuclear small diameter proteins was three-fold (P < 0.01), and the size of large diameter aggregates was more than four-fold in experimental lenses compared with controls. The diameter of crystallin aggregates in the UVA-irradiated lens nucleus was estimated to be 350 nm, a size able to scatter light. No significant changes in protein size were detected in the anterior cortex of UVA-irradiated lenses. It is presumed that the presence of a UVA chromophore in the guinea pig lens (NADPH bound to zeta crystallin), as well as traces of oxygen, contributed to UVA-induced crystallin aggregation. The results indicate a potentially harmful role for UVA light in the lens nucleus. A similar process of UVA-irradiated protein aggregation may take place in the older human lens nucleus, accelerating the formation of human nuclear cataract. [source] Morphometric Analysis of the Canal System of Cortical Bone: An Experimental Study in the Rabbit Femur Carried Out with Standard Histology and Micro-CTANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2010U. E. Pazzaglia Summary The osteonal pattern of cortical bone is gradually built around the intracortical vessels by the progression of the cutting cones (secondary remodelling); therefore, the central canal size can be used as index of the remodelling activity. An experimental model in the rabbit femur was used to investigate, through central canal morphometry and frequency distribution analysis, the remodelling activity, comparing the middle of the diaphysis (mid-shaft) with the extremity (distal-shaft) and at the same level sectors and layers of the cortex in transversal sections. The study documented a higher density of canals in the mid-shaft than in the distal-shaft and a higher remodelling in the distal-shaft. There were no significant differences between dorsal, ventral, medial and lateral sectors at both mid-shaft and distal-shaft levels, while the number of canals was higher in the sub-periosteal layers than in the sub-endosteal. A lower threshold of 40 ,m2 was observed in the central canal area. Sealed osteons in the midshaft were 22.43% of the total number of osteons of the central canal area between 40 and 200 ,m2 and 0.44% of those of the distal-shaft. Micro-CT allowed a 3D reconstruction of the vascular canal system, which confirmed the branched network pattern rather than the trim architecture of the traditional representation. Some aspects like the lower threshold of the central canal size and the sealed osteons documented the plasticity of the system and its capacity for adaptation to changes in the haemodynamic conditions. [source] A novel approach for root distribution analysis of linear time-invariant systems using Routh and Fuller tablesASIAN JOURNAL OF CONTROL, Issue 3 2009S. N. Sivanandam Abstract The root distribution of a given characteristic equation of a linear time-invariant system can be analyzed with the help of a Routh table using the elements of the first column in the table. In the case of unstable systems, sometimes, a zero element may appear in the third row of the first column of the Routh array. This prematurity can be suitably handled as indicated by various authors. In this paper, the given characteristic polynomial having roots in the right hand plane is multiplied by a suitable polynomial, and Routh and Fuller tables are applied for the resultant polynomial to infer the complete root distribution. Further, the column polynomials from each table are adopted to know more about root distribution, which forms the core of the proposed work. The Routh table helps in counting and locating roots in the s -plane, and the Fuller table helps in depicting whether the roots are distinct or complex in nature. In this regard, it is shown in this paper that the simultaneous integration of Routh and Fuller tables yields a good amount of information regarding the root distribution in the s -plane. The newly presented procedure is illustrated with examples. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Plantar pressure distribution analysis in normal weight young women and men with normal and claw feet: A cross-sectional studyCLINICAL ANATOMY, Issue 4 2005G. Gravante Abstract We analyzed the plantar support in 72 normal-weight young voluntaries (46 women, 26 men), by a baropodometric platform. We considered subjects with claw foot (CFS) and subjects with normal foot (NFS). We found a significant reduction of total plantar support surface in the CFS (P < 0.0001 for women, P < 0.001 for men), due to the reduction of the forefoot and rear foot areas of both plantar imprints. Indeed, CFS of both sexes exhibited higher values of both plantar pressure and peak pressure, compared to the NFS. Moreover, the load per units of plantar surface increased in CFS compared to the NFS. In conclusion, the reduction of plantar support surfaces in CFS of both sexes was associated to a major load per units of plantar surface in the forefoot and rear foot areas, and this may be a risk factor to lower extremity overuse injuries. Clin. Anat. 18:245,250, 2005. © 2005 Wiley-Liss, Inc. [source] |