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Larger Diameter (larger + diameter)
Selected AbstractsLaminin-5 stimulates hepatocellular carcinoma growth through a different function of ,6,4 and ,3,1 integrins,HEPATOLOGY, Issue 6 2007Carlo Bergamini Hepatocellular carcinoma (HCC) growth severely affects prognosis. Ki-67, a known marker of cell proliferation, is a negative prognostic factor in HCC. Growth factors such as the epidermal growth factor (EGF) induce HCC cell proliferation but do not explain the great heterogeneity of HCC growth. Laminin-5 (Ln-5) is an extracellular matrix protein (ECM) present in the tissue microenvironment of HCC. The two main receptors for Ln-5, integrins ,3,1 and ,6,4, are expressed on the cell surface of HCC cells. The aim of this study is to investigate an alternative mechanism of HCC growth whereby Ln-5 promotes HCC cell proliferation through ,3,1 and ,6,4. HCC tissues containing Ln-5 display a larger diameter and higher number of positive cells for Ki-67, a well known proliferative index, as determined by double immunofluorescence staining and real-time PCR on microdissected tissues. In vitro, Ln-5, but not collagen I, collagen IV or fibronectin, induces proliferation as much as EGF does, via Erk phosphorylation as a consequence of ,4 integrin phosphorylation. However, the two HCC cell lines do not proliferate in presence of Ln-5 despite ,4 integrin and Erk1/2 activation. After transfection with ,3 integrin, in the presence of Ln-5 one of these HCC cell lines acquires a proliferative activity whereas one of the proliferative HCC cell lines, knocked-down for ,3 integrin, loses its proliferative activity. Conclusions: Our study suggests a new mechanism of HCC growth whereby Ln-5 stimulates proliferation via a different function of ,6,4 and ,3,1. (HEPATOLOGY 2007.) [source] Preparation of poly(ester imide) ultrafine fibers by gas-jet/electrospinningJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2009Bing Wang Abstract In this study, ultrafine fibers of poly(ester imide) (PEI) were produced by gas-jet/electrospinning of its solutions in mixtures of phenol and dichloromethane (DCM). The process parameters, including the solution concentration, gas flow rate, applied voltage, tip-to-collector distance (TCD), and inner diameter of the metal needle, were investigated by scanning electron microscopy. The results show that the solution concentration, gas flow rate, TCD, and inner diameter of the needle were the most important process parameters influencing the average diameter and morphology of the PEI gas-jet/electrospun fibers. An increase in the solution concentration resulted in a larger average diameter in the PEI gas-jet/electrospun fibers. Mixed-bead fibers were obtained when the concentration of PEI in phenol/DCM was below 20 wt % during gas-jet/electrospinning. A larger diameter of the capillary and a smaller gas flow rate favored the formation of ultrafine fibers with thicker fibers. Thinner and uniform PEI fibers with an average diameter of 298 nm were formed at a TCD of 25 cm. On the basis of the systematic parameters study, uniform PEI ultrafine fibers with an average diameter of 293 nm were prepared by this gas-jet/electrospinning with the following optimal process parameters: the concentration of the polymer solution was 20 wt %, the gas flow rate was 10.0 L/min, the applied voltage was 25.0 kV, the TCD was 25 cm, and the inner diameter of the metal needle was 0.24 mm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Structural response of Caribbean dry forests to hurricane winds: a case study from Guánica Forest, Puerto RicoJOURNAL OF BIOGEOGRAPHY, Issue 3 2006Skip J. Van Bloem Abstract Aim, Tropical dry forests in the Caribbean have an uniquely short, shrubby structure with a high proportion of multiple-stemmed trees compared to dry forests elsewhere in the Neotropics. Previous studies have shown that this structure can arise without the loss of main stems from cutting, grazing, or other human intervention. The Caribbean has a high frequency of hurricanes, so wind may also influence forest stature. Furthermore, these forests also tend to grow on soils with low amounts of available phosphorus, which may also influence structure. The objective of this study was to assess the role of high winds in structuring dry forest, and to determine whether soil nutrient pools influence forest response following hurricane disturbance. Location, Guánica Forest, Puerto Rico. Methods, Over 2000 stems in five plots were sampled for hurricane effects within 1 week after Hurricane Georges impacted field sites in 1998. Sprout initiation, growth, and mortality were analysed for 1407 stems for 2 years after the hurricane. Soil nutrient pools were measured at the base of 456 stems to assess association between nutrients and sprout dynamics. Results, Direct effects of the hurricane were minimal, with stem mortality at < 2% and structural damage to stems at 13%, although damage was biased toward stems of larger diameter. Sprouting response was high , over 10 times as many trees had sprouts after the hurricane as before. The number of sprouts on a stem also increased significantly. Sprouting was common on stems that only suffered defoliation or had no visible effects from the hurricane. Sprout survival after 2 years was also high (> 86%). Soil nutrient pools had little effect on forest response as a whole, but phosphorus supply did influence sprout dynamics on four of the more common tree species. Main conclusions, Hurricanes are able to influence Caribbean tropical dry forest structure by reducing average stem diameter and basal area and generating significant sprouting responses. New sprouts, with ongoing survival, will maintain the high frequency of multi-stemmed trees found in this region. Sprouting is not limited to damaged stems, indicating that trees are responding to other aspects of high winds, such as short-term gravitational displacement or sway. Soil nutrients play a secondary role in sprouting dynamics of a subset of species. The short, shrubby forest structure common to the Caribbean can arise naturally as a response to hurricane winds. [source] Morphology and Crystalline Structure of Poly(, -Caprolactone) Nanofiber via Porous Aluminium Oxide TemplateMACROMOLECULAR MATERIALS & ENGINEERING, Issue 9 2006Yang Chen Abstract Summary: Poly(, -caprolactone) (PCL) nanofibers with a dimension of about 150 nm were successfully fabricated by using a process of extruding PCL solution via a porous aluminium oxide template and then solidifying in methanol. The morphology, melting behavior and crystalline structure of the nanofibers were investigated by using scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results revealed that the weight-average molecular weight () of PCL hardly influenced the morphology of the nanofibers. However, the melting temperature (Tm) of the PCL crystalline increased slightly from 55.4 to 57.5,°C with an increase in . The accessional pressure and the presence of the porous template played an important role in the improvement of the orientation and crystallization structures of the polymer chains when they were passing through the nano-scale porous channel, leading to the conglomeration of the fiber and the much larger diameter than those from the pressure-induced extrusion process. Furthermore, comparing the processes with and without accessional pressure, the crystallinity of the nanofibers obtained under 0.2 MPa pressure increased, and the diffraction for the (001) lattice plane occurred. SEM image of PCL nanofibers extruded via a porous aluminium oxide template with the aid of pressure. [source] Impact of pro-oxidant agents on the morula-blastocyst transition in bovine embryosMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2005Jean-Magloire Feugang Abstract Exposing day 5 bovine morulae to reactive oxygen species induces a delayed degeneration of some blastocysts on day 8 post-insemination (pi) but without affecting the blastocyst rates. The aim of this study was to characterize the resisting and the degenerating population of blastocysts. The kinetics of degeneration of the embryos exposed to the two pro-oxidant agents: 2,2,-azobis (2-amidinopropane) dihydrochloride (AAPH) and buthionine sulfoximine (BSO) was evaluated using time-lapse cinematography. With both agents the first signs of degeneration appeared at day 7.5 pi but the duration of the degeneration process was shorter in presence of AAPH than BSO (4.2 vs. 12.5 hr, ANOVA, P,<,0.05). The resisting blastocysts derived from morulae with a larger diameter (mean diameter: 161 vs. 154 ,m, ANOVA, P,<,0.05) and showed an earlier cavitation (135 vs. 142 hpi, P,<,0.05) than the degenerating ones. The profile of protein neosynthesis at day 7 was not affected by the treatment. The proportion of male embryos was more important in the resisting than in the degenerating population (70 vs. 55%, ,2, P,<,0.05) especially when the stress was induced by AAPH. The quality of the resisting embryos, measured by the total cell number and the rate of apoptosis, did not seem to be affected when compared to control embryos. In conclusion, resistance to oxidative stress seems related to the kinetics of development and/or the sex of the embryos. Resisting embryos apparently display a quality similar to untreated embryos. Mol. Reprod. Dev. © 2005 Wiley-Liss, Inc. [source] Structure, stability and electronic properties of composite Mo1,xNbxS2 nanotubesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2006V. V. Ivanovskaya Abstract The effect of Mo , Nb substitution on the electronic structure of MoS2 nanotubes has been investigated using the density functional tight binding method (DFTB). It has been found that composite Mo1,xNbxS2 nanotubes (with Nb contents of 5, 10 and 25 at%) are more stable than the corresponding pure tubes, especially for larger tube diameters. The defect-formation energy indicates that the most stable dopant arrangement is a NbS2 stripe along the tube direction. However, entropy effects may favor a random arrangement of Nb dopant atoms at high temperatures in the tubes with a larger diameter. All of the studied Mo1,xNbxS2 nanotubes have metallic properties, independent of their chirality, diameters and ordering type of substitutional atoms. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Tree and forest characteristics influence sleeping site choice by golden lion tamarinsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 9 2007Sarah J. Hankerson Abstract Lion tamarin monkeys are among a small number of primates that repeatedly use a few tree holes for the majority of their sleeping sites. To better understand why lion tamarins rely on tree holes as sleeping sites, we compared the physical characteristics of frequently used sleeping sites, infrequently used sleeping sites, and randomly selected forest locations at multiple spatial scales. From 1990 to 2004, we recorded 5,235 occurrences of sleeping site use by 10 groups of golden lion tamarins (Leontopithecus rosalia) in Poço das Antas Reserve, Rio de Janeiro State, Brazil. Of those, 63.6% were tree holes. Bamboo accounted for an additional 17.5% of observations. Frequently used tree holes were more likely to be found in living trees and their entrances were at lower canopy heights than infrequently used tree holes. We also found that frequently used sleeping sites, in comparison to random sites, were more likely to be found on hillsides, be close to other large trees, have a lower percent of canopy cover, and have larger diameter at breast height. Topography and small-scale variables were more accurate than were habitat-level classifications in predicting frequently used sleeping sites. There are ample tree holes available to these lion tamarins but few preferred sites to which they return repeatedly. The lion tamarins find these preferred sites wherever they occur including in mature forest and in relics of older forest embedded in a matrix of secondary forest. Am. J. Primatol. 69:976,988, 2007. © 2007 Wiley-Liss, Inc. [source] Evaluating anatomical research in surgery: a prospective comparison of cadaveric and living anatomical studies of the abdominal wallANZ JOURNAL OF SURGERY, Issue 12 2009Warren M. Rozen Abstract Background:, Cadaveric research has widely influenced our understanding of clinical anatomy. However, while many soft-tissue structures remain quiescent after death, other tissues, such as viscera, undergo structural and functional changes that may influence their use in predicting living anatomy. In particular, our understanding of vascular anatomy has been based upon cadaveric studies, in which vascular tone and flow do not match the living situation. Methods:, An angiographic analysis of the abdominal wall vasculature was performed using plain film and computed tomography angiography in 60 cadaveric hemi-abdominal walls (from 31 cadavers) and 140 living hemi-abdominal walls (in 70 patients). The deep inferior epigastric artery (DIEA) and all of its perforating branches larger than 0.5 mm were analysed for number, calibre and location. Results:, Both large, named vessels and small calibre vessels show marked differences between living anatomy and cadaveric specimens. The DIEA was of larger diameter (4.2 mm versus 3.1 mm, P < 0.01) and had more detectable branches in the cadaveric specimens. Perforators were of greater calibre (diameter 1.5 mm versus 0.8 mm, P < 0.01) and were more plentiful (16 versus 6, P < 0.01) in cadaveric specimens. However, the location of individual vessels was similar. Conclusions:, Cadaveric anatomy displays marked differences to in vivo anatomy, with the absence of living vascular dynamics affecting vessel diameters in cadaveric specimens. Blood vessels are of greater measurable calibre in cadaveric specimens than in the living. Consequently, cadaveric anatomy should be interpreted with consideration of post-mortem changes, while living anatomical studies, particularly with the use of imaging technologies, should be embraced in anatomical research. [source] A Study on Increasing Separation Efficiency of an Industrial, Compound Distillation ColumnASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2002Shengjing Mu Simulation of a multistage distillation column is often required for its design and operation A debottieneck study for an acetic acid (HAc) dehydration column is presented in this paper. The column is consists of 4 structured packing sections at the top, a sieve tray section with smaller diameter in the middle, and a sieve tray section with larger diameter at the bottom By using steady-state simulation, the bottleneck to increasing the efficiency of separation is identified to be the middle sieve tray section with smaller diameter and smaller tray spacing Renovation schemes without any additional investment on equipment are proposed [source] Nerve growth factor-induced substance P in capsaicin-insensitive vagal neurons innervating the lower mouse airwayCLINICAL & EXPERIMENTAL ALLERGY, Issue 9 2004Q. T. Dinh Summary Background Nerve growth factor (NGF) is elevated in allergic diseases such as bronchial asthma and can lead to an induction of substance P (SP) and related neuropeptides in guinea-pigs large-diameter, neurofilament-positive airway neurons. Objective In the present study, the effect of NGF on tyrosine kinase receptor trkA and the capsaicin receptor TRPV1 expression in airway-specific vagal sensory neurons located in the jugular,nodose ganglia complex (JNC) of mice was investigated. Methods Using retrograde neuronal tracing in combination with double-labelling immunohistochemistry, SP, trkA- and TRPV1-receptor expression was examined in airway-specific sensory neurons of BALB/c mice before and after NGF treatment. Results NGF injected into the lower airway was able to induce SP (13.0±2.03% vs. 5.9±0.33%) and trkA expression (78±2.66% vs. 60±2.11%) in larger diameter (>25 ,m), capsaicin-insensitive and trkA-positive vagal sensory neurons that were retrograde-labelled with Fast Blue dye from the main stem bronchi. Conclusion Based on the extent of SP and trkA co-expression in airway-specific neurons by NGF treatment, the present study suggests that, following a peripheral activation of trkA receptor on SP afferent by NGF which is elevated in allergic inflammation, there may be trkA-mediated SP induction to mediate neurogenic airway inflammation. [source] The deaf mouse mutant whirler suggests a role for whirlin in actin filament dynamics and stereocilia developmentCYTOSKELETON, Issue 7 2007Mette M. Mogensen Abstract Stereocilia, finger-like projections forming the hair bundle on the apical surface of sensory hair cells in the cochlea, are responsible for mechanosensation and ultimately the perception of sound. The actin cytoskeleton of the stereocilia contains hundreds of tightly cross-linked parallel actin filaments in a paracrystalline array and it is vital for their function. Although several genes have been identified and associated with stereocilia development, the molecular mechanisms responsible for stereocilia growth, maintenance and organisation of the hair bundle have not been fully resolved. Here we provide further characterisation of the stereocilia of the whirler mouse mutant. We found that a lack of whirlin protein in whirler mutants results in short stereocilia with larger diameters without a corresponding increase in the number of actin filaments in inner hair cells. However, a decrease in the actin filament packing density was evident in the whirler mutant. The electron-density at the tip of each stereocilium was markedly patchy and irregular in the whirler mutants compared with a uniform band in controls. The outer hair cell stereocilia of the whirler homozygote also showed an increase in diameter and variable heights within bundles. The number of outer hair cell stereocilia was significantly reduced and the centre-to-centre spacing between the stereocilia was greater than in the wildtype. Our findings suggest that whirlin plays an important role in actin filament packing and dynamics during postnatal stereocilium elongation. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] Intermittent watt-level ultrasonication facilitates vancomycin release from therapeutic acrylic bone cementJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009Xun-Zi Cai Abstract Ultrasound holds promise for enhancing the vancomycin release from cement though the length of time when local drug level exceeded the minimum inhibitory concentration (T>MIC) was not prolonged by the previous protocol of milliwatt-level ultrasonication. Here vancomycin-loaded cements were subjected to continuous watt-level ultrasonication (CUG), intermittent watt-level ultrasonication (IUG) or no ultrasonication (NUG) for 14 d during immersion in 40-ml phosphate buffered saline (PBS) for 28 d. The T>MIC for IUG was more than three times that for NUG. In contrast, T>MIC for CUG was slightly shortened. The subtherapeutic release of vancomycin between 15 d and 28 d for IUG was one-ninth that for NUG. The fitting equations indicated a significant enhancement on the burst release and the slow release for IUG; however, the continuous ultrasonication hampered the slow release. SEM images exhibited denser craters and pores with larger diameters and less residual drug in specimens from IUG relative to those from both CUG and NUG. Intermittent watt-level ultrasonication improved the ultrasound-enhanced vancomycin release from cement in view of the prolonged T>MIC and the inhibited subtherapeutic release compared with continuous ultrasonication. The mechanisms may be associated with the distinctive effects of detaching forces and pushing forces by acoustic microstreams. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Cytoarchitectonics and afferent/efferent reorganization of neurons in layers II and III of the lateral entorhinal cortex in the mouse pilocarpine model of temporal lobe epilepsyJOURNAL OF NEUROSCIENCE RESEARCH, Issue 6 2008Dong Liang Ma Abstract With the mouse pilocarpine model of temporal lobe epilepsy (TLE), we showed a progressive loss of both principal cells and calbindin (CB)-, calretinin (CR)-, and parvalbumin (PV)-immunopositive interneurons in layers II,III of lateral entorhinal cortex (LEnt) from 2 months to 1 year after pilocarpine-induced status epilepticus (PISE). In the efferent pathway of LEnt, more Phaseolus vulgaris leucoagglutinin (PHA-L)-labelled en passant and terminal boutons with larger diameters were shown in the hippocampus and subiculum; in the prefrontal, piriform, and perirhinal cortices; and in the amygdaloid complex in experimental mice at the two time points compared with the control after iontophoretical injection of an anterograde tracer PHA-L into the LEnt. Furthermore, the numbers of CB- or CR-immunopositive neurons contacted by PHA-L-labelled en passant and terminal boutons decreased in most of these areas at 2 months or 1 year after PISE. In the afferent pathway of LEnt, the numbers of retrogradely labelled neurons were reduced significantly in the ipsilateral piriform cortex and endopiriform nucleus at 2 months and 1 year and in the reuniens thalamic nucleus only at 1 year after injection of a retrograde tracer cholera toxin B subunit (CTB) into the LEnt. The percentages of the number of CTB and CB or CR double-labelled neurons of all the retrogradely labelled neurons were also decreased in the reunions thalamic nucleus at 1 year after PISE. It is concluded that both cytoarchitectonic change and reorganization of afferent and efferent pathways in LEnt may be involved in the occurrence of TLE. © 2007 Wiley-Liss, Inc. [source] Long-term effects of porcine small intestine submucosa on the healing of medial collateral ligament: A functional tissue engineering studyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2006Rui Liang Abstract Porcine small intestinal submucosa (SIS) was previously shown to enhance the mechanical properties of healing medial collateral ligaments (MCL), and the histomorphological appearance and collagen type V/I ratio were found to be close to those of normal MCL. We hypothesized that at a longer term, 26 weeks, SIS could guide a better organized neo-ligament formation, increasing mechanical properties and increasing collagen fibril diameters mediated by a reduction in collagen type V. A 6 mm gap injury in the right MCL was surgically created in 38 rabbits, while the contralateral intact MCL served as a sham-operated control. In half the animals, a strip of SIS was sutured onto the severed ends. In the other half, no SIS was applied. The cross-sectional area (CSA) was determined with a laser micrometer system. The femur,MCL,tibia complex was mechanically tested in uniaxial tension. Histomorphology was determined through H&E and immunofluorescent staining and transmission electron microscopy (TEM). Sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine collagen type V/I ratio. SIS-treated MCLs displayed a 28% reduction in CSA, a 33% increase in tangent modulus, and a 50% increase in tensile strength compared with the nontreated group (p,<,0.05). TEM showed groups of collagen fibrils with larger diameters in the SIS-treated ligaments in comparison with uniformly small fibrils for the nontreated group. H&E staining showed more densely stained collagen fibers in the SIS-treated group aligned along the longitudinal axis with more interspersed spindle-shaped cells. Immunofluorescent staining showed less collagen type V signals, confirmed by a 5% lower ratio of collagen type V/I compared with the nontreated controls (p,<,0.05). The findings extend the shorter term 12-week results, and support the potential of porcine SIS as a bioscaffold to enhance ligament healing. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Morphological variation of Aechmea distichantha (Bromeliaceae) in a Chaco forest: habitat and size-related effectsPLANT BIOLOGY, Issue 3 2009L. Cavallero Abstract Plants show different morphologies when growing in different habitats, but they also vary in their morphology with plant size. We examined differences in sun- and shade-grown plants of the bromeliad Aechmea distichantha with respect to relationships between plant size and variables related to plant architecture, biomass allocation and tank water dynamics. We selected vegetative plants from the understorey and from forest edges of a Chaco forest, encompassing the whole size range of this bromeliad. Plant biomass was positively correlated with most architectural variables and negatively correlated with most biomass allocation variables. Understorey plants were taller and had larger diameters, whereas sun plants had more leaves, larger sheath area, sheath biomass and sheath mass fraction. All tank water-related variables were positively correlated with plant biomass. Understorey plants had a greater projected leaf area, whereas sun plants had higher water content and evaporative area. Plasticity indices were higher for water-related than for allocation variables. In conclusion, there were architectural and biomass allocation differences between sun- and shade-grown plants along a size gradient, which, in turn, affected tank water-related variables. [source] Scanning electron microscopic analysis of different drug eluting stents after failed implantation: From nearly undamaged to major damaged polymers,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 6 2010Marcus Wiemer MD Abstract Background: Implantation of drug eluting stents (DES) in tortuous and/or calcified vessels is much more demanding compared with implantation of bare metal stents (BMS) due to their larger diameters. It is unknown whether drug eluting stent coatings get damaged while crossing these lesions. Methods: In 42 patients (34 male, 68.1 ± 10 years) with 45 calcified lesions (15.9 mm ± 7.9 mm), DES could not be implanted, even after predilatation. Diabetes was present in 19 patients (45 %). Sixty-one stents were used; 19 Cypher selectÔ, 18 Taxus LibertéÔ, 10 CoStarÔ, 5 Endeavor RXÔ, 4 Xience VÔ. 3 Janus CarbostentÔ, 1 Yukon Choice SÔ, and 1 AxxionÔ DES. The entire accessible surface area of these stents, in either the unexpanded and expanded state, were examined with an environmental scanning electron microscope (XL30 ESEM, Philips) to evaluate polymer or surface damage. Results: The polymers of Taxus Liberte, Cypher Select, Xience V, CoStar, and Janus DES were only slightly damaged (less than 3% of surface area), whereas the Endeavor RX Stents showed up to 20% damaged surface area. In DES without a polymer (Yukon and Axxion), it could be shown that most of the stent surface (up to 40%) were without any layer of drug. Conclusion: Placement of drug eluting stents in tortuous vessels and/or calcified lesions could cause major surface damage by scratching and scraping of the polymer or drug by the arterial wall, even before implantation. There were remarkable differences among the stents examined, only minor damage with the Cypher, Taxus Costar, Janus, and Xience V, whereas the Endeavor, the Yukon, and the Janus DES showed large areas of surface injury. © 2009 Wiley-Liss, Inc. [source] | ||||||||||||||||