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Outer Surface (outer + surface)
Terms modified by Outer Surface Selected AbstractsAlar Reconstruction with Subcutaneous Pedicled Nasolabial Flap: Difficulties, Considerations, and Conclusions for This ProcedureDERMATOLOGIC SURGERY, Issue 10 2005Fumiya Iwao MD Background. The subcutaneous pedicled nasolabial flap is a useful material for alar reconstruction. Objective. This article describes the difficulties and considerations in this procedure and discusses the procedural problems involved, drawing conclusions from them. Methods. Case 1: a folded flap was used with a conchal cartilage strut sandwich. Case 2: only a folded flap was used. Case 3: the flap was used to cover the outer surface of the ala, and a mucoperiosteal graft from the hard palate was used for the ala lining. Results. The cartilage strut was not sufficient to support the shape of the ala in case 1. Harvesting a sufficiently wide flap is thought to be important. However, a folded flap had some drawbacks, with the formation of a thick alar rim. Conclusions. The combination of a flap for the outer surface and a mucoperiosteal graft as a lining is thought to be an excellent option for alar reconstruction. [source] Differential growth and multicellular villi direct proepicardial translocation to the developing mouse heartDEVELOPMENTAL DYNAMICS, Issue 1 2008Laurel S. Rodgers Abstract In the mammalian system the proepicardium (PE) arises from mesothelium of the septum transversum before translocation to the heart where it forms the epicardium and progenitor cells of the coronary vessels. Despite its importance, the process in which PE cells translocate to the myocardium in mammals is not well defined. The current paradigm states that cellular cysts of PE float across the pericardial space and contact the outer surface of the myocardium. This mechanism does not provide a satisfactory explanation for the directionality or localization of PE migration. To better define PE migration, we performed a detailed study of mouse PE development. We provide thorough documentation that redefines the size of the PE migratory field and the mechanism of migration. Our new model incorporates differential growth and direct contact between multicellular PE villi and the myocardium as mechanisms in formation of the epicardium. Developmental Dynamics 237:145,152, 2008. © 2007 Wiley-Liss, Inc. [source] Application of Exchangeable Biochemical Reactors with Oxidase-Catalase-Co-immobilizates and Immobilized Microorganisms in a Microfluidic Chip-CalorimeterENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 5 2008M. Leifheit Abstract Several methods for the quantitative detection of different compounds, e.g., L -amino acids, sugars or alcohols in liquid media were developed by application of an automatic measuring unit including a fluid chip-calorimeter FCC-21. For this purpose, enzymes were immobilized covalently on the inner and outer surface of CPG (controlled porous glass)-spherules with an outer diameter of 100,,m and filled into a micro flow-through reaction chamber (VR = 20,,L). The design of the measuring cell allows for easy insertion into the calorimeter device of a stored series of comfortably pre-fabricated measuring cells. These cells can be filled with different enzyme immobilizates. Different oxidases were used and co-immobilized with catalase for the improvement of the detection sensitivity. A signal amplification could be achieved up to a factor of 3.5 with this configuration. ,- D -glucose, ethanol and L -lysine could be detected in a range of 0.25,1.75,mM using glucose oxidase, alcohol oxidase and lysine oxidase. The group of oxidases in combination with the enzymatic catalysis of the intermediate H2O2 allows the quantitative detection of a large number of analytes. A good measurement and storage stability could be achieved for several weeks by this immobilization method. In addition to enzyme-based detection reactions, it was shown that living microorganisms can be immobilized in the reaction chamber. Thus, the system can be used as a whole-cell biosensor. The quantitative detection of phenol in the range of 10,100,,M could be performed using the actinomycete Rhodococcus sp. immobilized on glass beads by means of embedding into polymers. [source] Cytoplasmic splicing of tRNA in Saccharomyces cerevisiaeGENES TO CELLS, Issue 3 2007Tohru Yoshihisa The splicing of nuclear encoded RNAs, including tRNAs, has been widely believed to occur in the nucleus. However, we recently found that one of the tRNA splicing enzymes, splicing endonuclease, is localized to the outer surface of mitochondria in Saccharomyces cerevisiae. These results suggested the unexpected possibility of tRNA splicing in the cytoplasm. To investigate this possibility, we examined whether cytoplasmic pre-tRNAs are bona fide intermediates for tRNA maturation in vivo. We isolated a new reversible allele of temperature-sensitive (ts) sen2 (HA-sen2-42), which encodes a mutant form of one of the catalytic subunits of yeast splicing endonuclease. The HA-sen2-42 cells accumulated large amounts of pre-tRNAs in the cytoplasm at a restrictive temperature, but the pre-tRNAs were diminished when the cells were transferred to a permissive temperature. Using pulse-chase/hybrid-precipitation techniques, we showed that the pre-tRNAs were not degraded but rather converted into mature tRNAs during incubation at the permissive temperature. These and other results indicate that, in S. cerevisiae, pre-tRNAs in the cytoplasm are genuine substrates for splicing, and that the splicing is indeed carried out in the cytoplasm. [source] Convection in the Earth's core driven by lateral variations in the core,mantle boundary heat fluxGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2000Steven John Gibbons Summary Moving core fluid maintains an isothermal core,mantle boundary (CMB), so lateral variations in the CMB heat flow result from mantle convection. Such variations will drive thermal winds, even if the top of the core is stably stratified. These flows may contribute to the magnetic secular variation and are investigated here using a simple, non-magnetic numerical model of the core. The results depend on the equatorial symmetry of the boundary heat flux variation. Large-scale equatorially symmetric (ES) heat flux variations at the outer surface of a rapidly rotating spherical shell drive deeply penetrating flows that are strongly suppressed in stratified fluid. Smaller-scale ES heat flux variations drive flows less dominated by rotation and so less inhibited by stratification. Equatorially anti-symmetric flux variations drive flows an order of magnitude less energetic than those driven by ES patterns but, due to the nature of the Coriolis force, are less suppressed by stratification. The response of the rotating core fluid to a general CMB heat flow pattern will then depend strongly on the subadiabatic temperature profile. Imposing a lateral heat flux variation linearly related to a model of seismic tomography in the lowermost mantle drives flow in a density stratified fluid that reproduces some features found in flows inverted from geomagnetic data. [source] A General Strategy to Disperse and Functionalize Carbon Nanotubes Using Conjugated Block CopolymersADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Jianhua Zou Abstract A general strategy to disperse and functionalize pristine carbon nanotubes in a single-step process is developed using conjugated block copolymers. The conjugated block copolymer contains two blocks: a conjugated polymer block of poly(3-hexylthiophene), and a functional non-conjugated block with tunable composition. When the pristine carbon nanotubes are sonicated with the conjugated block copolymers, the poly(3-hexylthiophene) blocks bind to the surface of de-bundled carbon nanotubes through non-covalent ,,, interactions, stabilizing the carbon nanotube dispersion, while the functional blocks locate at the outer surface of carbon nanotubes, rendering the carbon nanotubes with desired functionality. In this paper, conjugated block copolymers of poly(3-hexylthiophene)- b -poly(methyl methacrylate), poly(3-hexylthiophene)- b -poly(acrylic acid), and poly(3-hexylthiophene)- b -poly(poly(ethylene glycol) acrylate) are used to demonstrate this general strategy. [source] Cover Picture: Assembly of Wiseana Iridovirus: Viruses for Colloidal Photonic Crystals (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006Mater. Abstract Assembly of colloids is a versatile tool for micro- and nanofabrication. Natural and artificially engineered viruses offer the opportunity to expand the functionality and versatility of such assemblies. The cover shows optically iridescent, thin polycrystalline arrays (background) as well as bulk pellets (inset right) that exhibit reversible hydration-dependent reflection spectra, as reported by Vaia and co-workers on p.,1086. The films and pellets were created in vitro with classical colloid-assembly techniques from Wiseana iridescent virus (inset, center) harvested from infected Wiseana spp larvae (inset, left). In,vitro assembly of Wiseana iridescent virus (WIV) yields iridescent pellets and films with structural color more vivid than in the native insect. WIV is icosahedral in shape, 140,nm in diameter, with 30,nm long fibrils attached to the outer surface, and exhibits a surface charge ca.,1/6th that of a comparable polymer colloid. The low surface charge and tethered chains on the virus surface allow the facile modification of the interparticle distance. Directed sedimentation yields predominantly an amorphous liquid-like packing of the virus. Such samples exhibit a broad reflection band that is angle independent and for which the broad maximum can be reversibly shifted from blue towards red with increased hydration. Slow sedimentation and flow-assisted assembly methods produce thin films with a polycrystalline morphology that exhibit narrower, more intense reflectivity peaks, which are hydration and angle dependent. This study points toward the potential of viral particles for photonic crystals where their unique structural features (icosahedral symmetry, extreme monodispersity, precise surface functionalization, and tethered surface chains of low surface-charge density) may lead to superior control of optical properties of their assembled arrays. [source] Steam absorption process of water/LiBr system inside vertical small bore pipesHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 1 2005Masanori Kiyota Abstract In a previous paper, a numerical model for absorption within vertical pipes was proposed and compared with the experiments. Agreements were good for pipes with an OD 28,15 mm but at 10 mm pipe experiments fell below the predicted values. For smaller diameters, the difference between the surface area of the falling liquid film and that of the outer surface of the pipe is not negligible and the thickness of the liquid film is also not negligible. In this paper a new model is formulated in cylindrical coordinates and experiments using pipes with 9.52 mm and 7 mm OD are done. Smooth pipes and two kinds of internally finned pipes, originally developed and used to enhance the heat transfer characteristics of the evaporator and condenser of a refrigerator using HFC as refrigerant, are tested in the experiments. The absorption performance is enhanced by 30% when compared to the smooth pipes, but the difference between the finned pipes is small. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(1): 18,28, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20040 [source] Improved accuracy for the Helmholtz equation in unbounded domainsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 15 2004Eli Turkel Abstract Based on properties of the Helmholtz equation, we derive a new equation for an auxiliary variable. This reduces much of the oscillations of the solution leading to more accurate numerical approximations to the original unknown. Computations confirm the improved accuracy of the new models in both two and three dimensions. This also improves the accuracy when one wants the solution at neighbouring wavenumbers by using an expansion in k. We examine the accuracy for both waveguide and scattering problems as a function of k, h and the forcing mode l. The use of local absorbing boundary conditions is also examined as well as the location of the outer surface as functions of k. Connections with parabolic approximations are analysed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Dynamic crack propagation with cohesive elements: a methodology to address mesh dependencyINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 1 2004F. Zhou Abstract In this paper, two brittle fracture problems are numerically simulated: the failure of a ceramic ring under centrifugal loading and crack branching in a PMMA strip. A three-dimensional finite element package in which cohesive elements are dynamically inserted has been developed. The cohesive elements' strength is chosen to follow a modified weakest link Weibull distribution. The probability of introducing a weak cohesive element is set to increase with the cohesive element size. This reflects the physically based effect according to which larger elements are more likely to contain defects. The calculations illustrate how the area dependence of the Weibull model can be used to effectively address mesh dependency. On the other hand, regular Weibull distributions have failed to reduce mesh dependency for the examples shown in this paper. The ceramic ring calculations revealed that two distinct phenomena appear depending on the magnitude of the Weibull modulus. For low Weibull modulus, the fragmentation of the ring is dominated by heterogeneities. Whereas many cracks were generated, few of them could propagate to the outer surface. Monte Carlo simulations revealed that for highly heterogeneous rings, the number of small fragments was large and that few large fragments were generated. For high Weibull modulus, signifying that the ring is close to being homogeneous, the fragmentation process was very different. Monte Carlo simulations highlighted that a larger number of large fragments are generated due to crack branching. Copyright © 2003 John Wiley & Sons, Ltd. [source] Rheology behavior of high-density polyethylene/diluent blends and fabrication of hollow-fiber membranes via thermally induced phase separationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2010Jianli Wang Abstract The phase-separation behavior of high-density polyethylene (HDPE)/diluent blends was monitored with a torque variation method (TVM). The torque variation of the molten blends was recorded with a rheometer. It was verified that TVM is an efficient way to detect the thermal phase behavior of a polymer,diluent system. Subsequently, polyethylene hollow-fiber membranes were fabricated from HDPE/dodecanol/soybean oil blends via thermally induced phase separation. Hollow-fiber membranes with a dense outer surface of spherulites were observed. Furthermore, the effects of the spinning temperature, air-gap distance, cold drawing, and HDPE content on the morphology and gas permeability of the resultant membranes were examined. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Formation of three-dimensional cell/polymer constructs for bone tissue engineering in a spinner flask and a rotating wall vessel bioreactorJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2002Vassilios I. Sikavitsas Abstract The aim of this study is to investigate the effect of the cell culture conditions of three-dimensional polymer scaffolds seeded with rat marrow stromal cells (MSCs) cultured in different bioreactors concerning the ability of these cells to proliferate, differentiate towards the osteoblastic lineage, and generate mineralized extracellular matrix. MSCs harvested from male Sprague,Dawley rats were culture expanded, seeded on three-dimensional porous 75:25 poly(D,L -lactic- co -glycolic acid) biodegradable scaffolds, and cultured for 21 days under static conditions or in two model bioreactors (a spinner flask and a rotating wall vessel) that enhance mixing of the media and provide better nutrient transport to the seeded cells. The spinner flask culture demonstrated a 60% enhanced proliferation at the end of the first week when compared to static culture. On day 14, all cell/polymer constructs exhibited their maximum alkaline phosphatase activity (AP). Cell/polymer constructs cultured in the spinner flask had 2.4 times higher AP activity than constructs cultured under static conditions on day 14. The total osteocalcin (OC) secretion in the spinner flask culture was 3.5 times higher than the static culture, with a peak OC secretion occurring on day 18. No considerable AP activity and OC secretion were detected in the rotating wall vessel culture throughout the 21-day culture period. The spinner flask culture had the highest calcium content at day 14. On day 21, the calcium deposition in the spinner flask culture was 6.6 times higher than the static cultured constructs and over 30 times higher than the rotating wall vessel culture. Histological sections showed concentration of cells and mineralization at the exterior of the foams at day 21. This phenomenon may arise from the potential existence of nutrient concentration gradients at the interior of the scaffolds. The better mixing provided in the spinner flask, external to the outer surface of the scaffolds, may explain the accelerated proliferation and differentiation of marrow stromal osteoblasts, and the localization of the enhanced mineralization on the external surface of the scaffolds. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 136,148, 2002 [source] Targeted Expression of SHH Affects Chondrocyte Differentiation, Growth Plate Organization, and Sox9 Expression,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2004Sara Tavella Abstract The role of Hedgehogs (Hh) in murine skeletal development was studied by overexpressing human Sonic Hedgehog (SHH) in chondrocytes of transgenic mice using the collagen II promoter/enhancer. Overexpression caused a lethal craniorachischisis with major alterations in long bones because of defects in chondrocyte differentiation. Introduction: Hedgehogs (Hhs) are a family of secreted polypeptides that play important roles in vertebrate development, controlling many critical steps of cell differentiation and patterning. Skeletal development is affected in many different ways by Hhs. Genetic defects and anomalies of Hhs signaling pathways cause severe abnormalities in the appendicular, axial, and cranial skeleton in man and other vertebrates. Materials and Methods: Genetic manipulation of mouse embryos was used to study in vivo the function of SHH in skeletal development. By DNA microinjection into pronuclei of fertilized oocytes, we have generated transgenic mice that express SHH specifically in chondrocytes using the cartilage-specific collagen II promoter/enhancer. Transgenic skeletal development was studied at different embryonic stages by histology. The expression pattern of specific chondrocyte molecules was studied by immunohistochemistry and in situ hybridization. Results: Transgenic mice died at birth with severe craniorachischisis and other skeletal defects in ribs, sternum, and long bones. Detailed analysis of long bones showed that chondrocyte differentiation was blocked at prehypertrophic stages, hindering endochondral ossification and trabecular bone formation, with specific defects in different limb segments. The growth plate was highly disorganized in the tibia and was completely absent in the femur and humerus, leading to skeletal elements entirely made of cartilage surrounded by a thin layer of bone. In this cartilage, chondrocytes maintained a columnar organization that was perpendicular to the bone longitudinal axis and directed toward its outer surface. The expression of SHH receptor, Patched-1 (Ptc1), was greatly increased in all cartilage, as well as the expression of parathyroid hormone-related protein (PTHrP) at the articular surface; while the expression of Indian Hedgehog (Ihh), another member of Hh family that controls the rate of chondrocyte maturation, was greatly reduced and restricted to the displaced chondrocyte columns. Transgenic mice also revealed the ability of SHH to upregulate the expression of Sox9, a major transcription factor implicated in chondrocyte-specific gene expression, in vivo and in vitro, acting through the proximal 6.8-kb-long Sox9 promoter. Conclusion: Transgenic mice show that continuous expression of SHH in chondrocytes interferes with cell differentiation and growth plate organization and induces high levels and diffuse expression of Sox9 in cartilaginous bones. [source] Selected pathological, immunohistochemical and ultrastructural changes associated with an infection by Diphyllobothrium dendriticum (Nitzsch, 1824) (Cestoda) plerocercoids in Coregonus lavaretus (L.) (Coregonidae)JOURNAL OF FISH DISEASES, Issue 8 2007B S Dezfuli Abstract The pathological changes induced by an infection of Diphyllobothrium dendriticum (Nitzsch, 1824) plerocercoids in powan, Coregonus lavaretus (L.), from Loch Lomond, Scotland, were assessed using immunohistochemical and ultrastructural techniques. In a sample of 26 powan, the occurrence of encysted plerocercoids of D. dendriticum on the outer surface of the stomach was 38.5% (n = 10) with the number of cysts ranging from 4 to 15 and measuring 4.2 ± 1.0 mm × 3.4 ± 0.9 mm (mean ± SD). Histological examination of intestinal samples also revealed plerocercoids (2,21) encapsulated within a proliferation of mesenteric fibrous tissues of the gastric wall and, occasionally, by the gut lamina propria-submucosa and lamina muscularis. In section, cysts were tri-layered and were formed from a series of concentric whorls of fibroblast and collagen fibre-based connective elements. The extent of necrosis within each muscle layer and the serosa of the stomach differed, notably within the latter that was marked by a chronic inflammatory reaction and fibrosis. Within the cyst and around it, a large number of degranulating mast cell/eosinophilic granule cells were seen, in addition to melano-macrophage centres. Immunohistochemical staining of sections of infected stomach revealed a high density of elements, in close proximity to plerocercoids, staining positive for serotonin, bombesin, substance P and galanin. Uninfected material did not present the same levels of activity. Sections through both infected and uninfected tissue were also tested for elements containing vasoactive intestinal peptide, met-enkephalin, calcitonin gene-related peptide, neuropeptide Y and nitric oxide synthase, but these were absent. [source] IN VITRO DIGESTIBILITY OF CHINESE TARTARY BUCKWHEAT PROTEIN FRACTIONS: THE MICROSTRUCTURE AND MOLECULAR WEIGHT DISTRIBUTION OF THEIR HYDROLYSATESJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2006XIAONA GUO ABSTRACT Our previous study showed that in vitro pepsin digestibility of Chinese tartary buckwheat protein was relatively low compared to those of other edible seeds. In vitro pepsin digestibilities of four protein fractions of tartary buckwheat, microstructure and molecular weight (MW) distributions of hydrolysates were investigated. In vitro pepsin digestion assay showed that the digestibilities of tartary buckwheat protein fractions were albumin (81.20%), globulin (79.56%), prolamin (66.99%) and glutelin (58.09%). Scanning electron microscopy showed that albumin and globulin fractions were digested by pitting from the outer surface to the inner part and were more digestible, while prolamin and glutelin fractions resisted digestion because only the outer surfaces of their protein bodies were digested and the interior was protected. MW distribution of the hydrolysates from the four protein fractions was determined by high-performance liquid chromatography. The hydrolysates of albumin mainly consisted of polypeptides with lower MW. The hydrolysates of glutelin had larger polypeptides together with small and medium-sized peptide fractions. [source] REMOVAL OF LIPID FROM SURFACES OF ROASTED PEANUTS BY SONICATION AS ASSESSED BY FLUORESCENCE AND SCANNING ELECTRON MICROSCOPYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2010PETER WAMBURA ABSTRACT Peanut oil migrates to the outer surface during roasting, where it comes into contact with oxygen, leading to the oxidation reactions. Because of its cleaning effect, power ultrasound (sonication) was used for removing surface lipid of roasted peanuts. Georgia green runner-type peanuts were roasted at 178C for 15 min. Roasted peanuts were subjected to lipid extraction in n-hexane by sonication. Fluorescent and electron scanning micrographs revealed that the surface of sonicated peanuts was free of oil stains, as opposed to that of freshly roasted peanuts. These results showed that power ultrasound could remove the lipids from peanut surfaces very effectively. Details of microstructure of sonicated peanuts as was observed using scanning electron microscope reveal that 10 min sonication was sufficient to extract most of the lipids on the roasted peanut surfaces. Fluorescence and scanning electron microscopy are useful in peanut analysis because they can detect lipids in low concentration. PRACTICAL APPLICATIONS There is increasing interest of quick procedures to examine the surfaces of roasted peanut samples after undergoing treatments, such as removal of lipids. This research demonstrated the significant use of fluorescent and scanning electron microscopes to quickly study the extent of lipid removal from the surface of roasted peanuts after power ultrasound treatment (sonication). [source] Toward an Implantable Wireless Cardiac Monitoring Platform Integrated with an FDA-Approved Cardiovascular StentJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2009ERIC Y. CHOW Ph.D. Continuous monitoring of blood pressure from a minimally invasive device in the pulmonary artery can serve as a diagnostic and early warning system for cardiac health. The foremost challenge in such a device is the wireless transfer of data and power from within the blood vessel to an external device while maintaining unrestricted flow through the artery. We present a miniaturized system, which is attached to the outer surface of a regular or drug-eluting FDA-approved stent. When expanded, the stent maintains a patent vessel lumen while allowing contact between the electronic sensors and the blood supply. The stent-based antenna can be used for both wireless telemetry and power transfer for the implanted electronics. Using the stent platform as both a radiating antenna and a structural support allows us to take advantage of an FDA-approved device whose safety and surgical procedure are well established. The electronics package has been reduced to an area of less than 1 mm2, with a thickness under 300 ,m. A minimally invasive implantation procedure allows the delivery of the stent-based implant in nearly any major vessel of the body. This article describes an initial prototype with two stents configured as a single dipole, a 2.4-GHz transmitter microchip, and a battery, and validates transcutaneous transmission through ex vivo and in vivo porcine studies. The results demonstrate the feasibility of a stent-based wireless platform for continuous monitoring of blood pressure. [source] Automatic model-based evaluation of magnetic resonance-guided radio frequency ablation lesions with histological correlationJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2004Roee S. Lazebnik PhD Abstract Purpose To develop a model-based method for automatic evaluation of radio frequency (RF) ablation treatment using magnetic resonance (MR) images. Materials and Methods RF current lesions were generated in a rabbit thigh model using MR imaging (MRI) guidance. We created a 12-parameter, three-dimensional, globally deformable model with quadric surfaces that delineates lesion boundaries and is automatically fitted to MR grayscale data. We applied this method to in vivo T2 - and contrast-enhanced (CE) T1 -weighted MR images acquired immediately post-ablation and four days later. We then compared results to manually segmented MR and three-dimensional registered corresponding histological boundaries of cellular damage. Results Resulting lesions featured a two-boundary appearance with an inner region and an outer hyperintense margin on MR images. For automated vs. manual MR boundaries, the mean errors over all specimens were 0.19 ± 0.51 mm and 0.27 ± 0.52 mm for the inner surface, and ,0.29 ± 0.40 mm and ,0.12 ± 0.17 mm for the outer surface, for T2 - and CE T1 -weighted images, respectively. For automated vs. histological boundaries, mean errors over all specimens were 0.07 ± 0.64 mm and 0.33 ± 0.71 mm for the inner surface, and ,0.27 ± 0.69 mm and 0.02 ± 0.43 mm for the outer surface, for T2 - and CE T1 -weighted images, respectively. All boundary errors compared favorably to MR voxel dimensions, which were 0.7 mm in-plane and 3.0 mm thick. Conclusion The method is accurate both in describing MR-apparent boundaries and in predicting histological response and has applications in lesion visualization, volume estimation, and treatment evaluation. J. Magn. Reson. Imaging 2004;19:245,254. © 2004 Wiley-Liss, Inc. [source] A novel inorganic hollow fiber membrane reactor for catalytic dehydrogenation of propaneAICHE JOURNAL, Issue 9 2009Zhentao Wu Abstract A novel inorganic hollow fiber membrane reactor (iHFMR) has been developed and applied to the catalytic dehydrogenation of propane to propene. Alumina hollow fiber substrates, prepared by a phase inversion/sintering method, possess a unique asymmetric structure that can be characterized by a very porous inner surface from which finger-like voids extend across ,80% of the fiber cross-section with the remaining 20% consisting of a denser sponge-like outer layer. In contrast to other existing Pd/Ag composite membranes, where an intermediate ,-Al2O3 layer is often used to bridge the Pd/Ag layer and the substrate, the Pd/Ag composite membrane prepared in this study was achieved by coating the Pd/Ag layer directly onto the outer surface of the asymmetric substrate. After depositing submicron-sized Pt (0.5 wt %)/,-alumina catalysts in the finger-like voids of the substrates, a highly compact multifunctional iHFMR was developed. Propane conversion as high as 42% was achieved at the initial stage of the reaction at 723 K. In addition, the space-time yields of the iHFMR were ,60 times higher than that of a fixed bed reactor, demonstrating advantages of using iHFMR for dehydrogenation reactions. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Developing bifunctional , -lactamase molecules with built-in target-recognizing module for prodrug therapy: identification of Enterobacter Cloacae P99 cephalosporinase loops suitable for randomization and phage-display selectionJOURNAL OF MOLECULAR RECOGNITION, Issue 6 2009Girja S. Shukla Abstract This study was focused on developing catalytically active , -lactamase enzyme molecules that have target-recognizing sites built within their scaffold. Using phage-display approach, nine libraries were constructed by inserting the randomized linear or cysteine-constrained heptapeptides in the five different loops on the outer surface of P99 , -lactamase molecule. The pIII signal peptide of Sec-pathway was employed for a periplasmic translocation of the , -lactamase fusion protein, which we found more efficient than the DsbA signal peptide of SRP-pathway. The randomized heptapeptide loops replaced native amino acids between positions 34Y- 37K, 238M- 246A, 275N- 280A, 305A- 311S, or 329I- 334I of the P99 , -lactamase molecules for generating the loop-1 to -5 libraries, respectively. The diversity of each loop library was judged by counting the primary and , -lactamase-active clones. The linear peptide inserts in the loop-2 library showed the maximum number of the , -lactamase-active clones, followed by the loop-5, loop-3, and loop-4. The insertion of the cysteine-constrained loops exhibited a dramatic loss of the enzyme-active , -lactamase clones. The complexity of the loop-2 linear library, as determined by the frequency and diversity of amino acid distributions in the randomized region, appears consistent with the standards of other types of phage display library systems. The selection of the loop-2 linear library on streptavidin protein as a test target identified several , -lactamase clones that specifically bound to streptavidin. In conclusion, this study identified the suitability of the loop-2 of P99 , -lactamase for constructing a phage-display library of the , -lactamase enzyme-active molecules that can be selected against a target. This is an enabling step in our long-term goal of developing bifunctional , -lactamase molecules against cancer-specific targets for enzyme prodrug therapy of cancer. Copyright © 2009 John Wiley & Sons, Ltd. [source] Ultrastructure of the embryonic snake skin and putative role of histidine in the differentiation of the shedding complexJOURNAL OF MORPHOLOGY, Issue 2 2002Lorenzo Alibardi Abstract The morphogenesis and ultrastructure of the epidermis of snake embryos were studied at progressive stages of development through hatching to determine the time and modality of differentiation of the shedding complex. Scales form as symmetric epidermal bumps that become slanted and eventually very overlapped. During the asymmetrization of the bumps, the basal cells of the forming outer surface of the scale become columnar, as in an epidermal placode, and accumulate glycogen. Small dermal condensations are sometimes seen and probably represent primordia of the axial dense dermis of the growing tip of scales. Deep, dense, and superficial loose dermal regions are formed when the epidermis is bilayered (periderm and basal epidermis) and undifferentiated. Glycogen and lipids decrease from basal cells to differentiating suprabasal cells. On the outer scale surface, beneath the peridermis, a layer containing dense granules and sparse 25,30-nm thick coarse filaments is formed. The underlying clear layer does not contain keratohyalin-like granules but has a rich cytoskeleton of intermediate filaments. Small denticles are formed and they interdigitate with the oberhautchen spinulae formed underneath. On the inner scale surface the clear layer contains dense granules, coarse filaments, and does not form denticles with the aspinulated oberhautchen. On the inner side surface the oberhautchen only forms occasional spinulae. The sloughing of the periderm and embryonic epidermis takes place in ovo 5,6 days before hatching. There follow beta-, mesos-, and alpha-layers, not yet mature before hatching. No resting period is present but a new generation is immediately produced so that at 6,10 h posthatching an inner generation and a new shedding complex are forming beneath the outer generation. The first shedding complex differentiates 10,11 days before hatching. In hatchlings 6,10 h old, tritiated histidine is taken up in the epidermis 4 h after injection and is found mainly in the shedding complex, especially in the apposed membranes of the clear layer and oberhautchen cells. This indicates that a histidine-rich protein is produced in preparation for shedding, as previously seen in lizard epidermis. The second shedding (first posthatching) takes place at 7,9 days posthatching. It is suggested that the shedding complex in lepidosaurian reptiles has evolved after the production of a histidine-rich protein and of a beta-keratin layer beneath the former alpha-layer. J. Morphol. 251:149,168, 2002. © 2002 Wiley-Liss, Inc. [source] Potential implications of endogenous aldehydes in ,-amyloid misfolding, oligomerization and fibrillogenesisJOURNAL OF NEUROCHEMISTRY, Issue 5 2006Kun Chen Abstract Aldehydes are capable of inducing protein cross-linkage. An increase in aldehydes has been found in Alzheimer's disease. Formaldehyde and methylglyoxal are produced via deamination of, respectively, methylamine and aminoacetone catalyzed by semicarbazide-sensitive amine oxidase (SSAO, EC 1.4.3.6. The enzyme is located on the outer surface of the vasculature, where amyloidosis is often initiated. A high SSAO level has been identified as a risk factor for vascular disorders. Serum SSAO activity has been found to be increased in Alzheimer's patients. Malondialdehyde and 4-hydroxynonenal are derived from lipid peroxidation under oxidative stress, which is also associated with Alzheimer's disease. Aldehydes may potentially play roles in ,-amyloid aggregation related to the pathology of Alzheimer's disease. In the present study, thioflavin-T fluorometry, dynamic light scattering, circular dichroism spectroscopy and atomic force microscopy were employed to reveal the effect of endogenous aldehydes on ,-amyloid at different stages, i.e. ,-sheet formation, oligomerization and fibrillogenesis. Formaldehyde, methylglyoxal and malondialdehyde and, to a lesser extent, 4-hydroxynonenal are not only capable of enhancing the rate of formation of ,-amyloid ,-sheets, oligomers and protofibrils but also of increasing the size of the aggregates. The possible relevance to Alzheimer's disease of the effects of these aldehydes on ,-amyloid deposition is discussed. [source] New Method to Prevent Bladder Dysfunction after Radical Hysterectomy for Uterine Cervical CancerJOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 1 2000Dr. Yoshinori Kuwabara Abstract Objective: The purpose was to improve the surgical procedures to prevent bladder dysfunction after radical hysterectomy. Methods: Twelve patients with stage Ib cervical cancer underwent intraoperative electrical stimulation to identify the vesical branches of the pelvic nerves. Autonomic nerve localization in the vesicouterine ligament was examined in 10 patients immunohistochemically. According to the results of the above studies a new method to preserve the vesical branches was developed. Grades of postoperative bladder dysfunction were compared between new (n = 19) and conventional methods (n = 18). Results: Electrical stimulation on the outer surface of the posterior sheath of the vesicouterine ligament caused the increase of intravesical pressure. S-100 protein localized also on this area. Postoperative compliance of the detrusor in cases with the new method demonstrated less decrement from preoperative values than in cases with the conventional method. The new method required significantly fewer days to achieve residual urine volumes less than 50 ml after surgery. Conclusions: The new method significantly reduces bladder dysfunction after radical hysterectomy. [source] Three-dimensional force measurements on oral implants: a methodological studyJOURNAL OF ORAL REHABILITATION, Issue 9 2000J. Duyck This paper describes a methodology that allows in vitro and in vivo quantification and qualification of forces on oral implants. Strain gauges are adapted to the outer surface of 5·5 and 7 mm standard abutments (Brånemark System®, Nobel Biocare, Sweden). The readings of the strain gauges are transformed into a numerical representation of the normal force and the bending moment around the X- and Y- axis. The hardware and the software of the 3D measuring device based on the strain gauge technology is explained and its accuracy and reliability tested. The accuracy level for axial forces and bending moments is 9.72 N and 2.5 N·cm, respectively, based on the current techniques for strain gauged abutments. As an example, an in vivo force analysis was performed in a patient with a full fixed prosthesis in the mandible. Since axial loads of 450 N and bending moments of 70 N·cm were recorded, it was concluded that the accuracy of the device falls well within the scope of our needs. Nevertheless, more in vivo research is needed before well defined conclusions can be drawn and strategies developed to improve the biomechanics of oral implants. [source] PROBING THE SURFACE OF LIVING DIATOMS WITH ATOMIC FORCE MICROSCOPY: THE NANOSTRUCTURE AND NANOMECHANICAL PROPERTIES OF THE MUCILAGE LAYER,JOURNAL OF PHYCOLOGY, Issue 4 2003Michael J. Higgins Atomic force microscopy (AFM) is used to investigate the topography and material properties of the mucilage layer of live cells of three benthic diatoms, the marine species Crasepdostauros australis E. J. Cox and Nitzschia navis-varingica Lundholm et Moestrup and the freshwater species Pinnularia viridis (Nitzsch) Ehrenberg. Contrary to previous studies, we show that this surface mucilage layer displays unique nanostructural features. In C. australis, tapping mode images revealed a soft mucilage layer encasing the silica cell wall, consisting of a smooth flat surface that was interrupted by regions with groove-like indentations, whereas force measurements revealed the adhesive binding of polymer chains. The elastic responses of these polymer chains, as they were stretched during force measurements, were successfully fitted to the worm-like chain model, indicating the stretching of mostly single macromolecules from which quantitative information was extracted. In P. viridis, tapping mode images of cells revealed a mucilage layer that had the appearance of densely packed spheres, whereas force measurements exhibited no adhesion. In N. navis-varingica, tapping mode images of the outer surface of this cell in the girdle region revealed the absence of a mucilage layer, in contrast to the other two species. In addition to these topographic and adhesion studies, the first quantitative measurement of the elastic properties of microalgal extracellular polymeric substance is presented and reveals significant spatial variation in the C. australis and P. viridis mucilage layers. This study highlights the capacity of AFM in elucidating the topography and mechanical properties of hydrated microalgal extracellular polymeric substance on a nanoscale. [source] Monte Carlo Simulation of Degradation of Porous Poly(lactide) Scaffolds, 1MACROMOLECULAR THEORY AND SIMULATIONS, Issue 9 2006Effect of Porosity on pH Abstract Summary: Monte Carlo method was used to simulate the degradation of porous PLA scaffolds. The simulated volume was assumed to be divided homogeneously between the pore and solid PLA with the ratio equal to the bulk porosity of the scaffold. The volume was divided into surface and bulk elements where the surface elements were in direct contact with the aqueous degradation medium, while the bulk elements were surrounded by the pore and solid PLA. The effect of degradation time on PLA ester groups and carboxylic acid end-groups for surface and bulk elements, pH, PLA degradation rate and mass loss, and PLA molecular weight distribution was simulated. For surface elements, pH remained constant at 7.4 over the entire time of degradation, while for bulk elements its value decreased significantly to as low as 5.8. The highest drop in pH within the scaffold was observed for the highest porosity of 90%. There was a lag time of at least 7 weeks in the mass loss for surface as well as bulk elements for porosities ranging from 70 to 90%. The mass loss for bulk elements was considerably faster than the surface elements. This difference in the rate of mass loss between the surface and bulk elements could affect the 3D morphology and dimensional stability of the scaffold in vivo as degradation proceeds. The simulation predicts that, due to differences in the rate of bulk and surface degradation, hollow structures could form inside the scaffold after 19, 17, and 15 weeks for initial porosities of 70, 80, and 90%, respectively. A schematic diagram illustrating the degradation of an element on the outer surface of the scaffold (surface element) versus an element within the volume of the scaffold (bulk element). [source] Consideration of magnetically-induced and conservative electric fields within a loaded gradient coilMAGNETIC RESONANCE IN MEDICINE, Issue 6 2006Weihua Mao Abstract We present a method to calculate the electric (E)-fields within and surrounding a human body in a gradient coil, including E-fields induced by the changing magnetic fields and "conservative" E-fields originating with the scalar electrical potential in the coil windings. In agreement with previous numerical calculations, it is shown that magnetically-induced E-fields within the human body show no real concentration near the surface of the body, where nerve stimulation most often occurs. Both the magnetically-induced and conservative E-fields are shown to be considerably stronger just outside the human body than inside it, and under some circumstances the conservative E-fields just outside the body can be much larger than the magnetically-induced E-fields there. The order of gradient winding and the presence of conductive RF shield can greatly affect the conservative E-field distribution in these cases. Though the E-fields against the outer surface of the body are not commonly considered, understanding gradient E-fields may be important for reasons other than peripheral nerve stimulation (PNS), such as potential interaction with electrical equipment. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Monoclonal antibody against rat podocyte-derived macrophagic cells reacts with crescent-forming cells in an experimental modelNEPHROLOGY, Issue 5 2003MICHIAKI ORIKASA SUMMARY: The origin of crescent-forming cells in crescentic glomerulonephritis has not been clarified in spite of the application of monoclonal antibodies (mAbs) against glomerular epithelial cells or monocytes/macrophages. This study was undertaken to characterize the cellular composition of crescents using a new marker, mAb OS-3, produced against macrophagic cells derived from podocytes in normal rat glomerular culture. Monoclonal antibody OS-3 was confirmed to be reactive with some normal epithelial cells of Bowman's capsule. Female Wistar Kyoto rats were injected with rabbit antiglomerular basement membrane (GBM) serum and killed at 2 h, 1, 3, 7, 14 days and 2 months, respectively. The mAb OS-3-positive cells were segmentally observed in glomeruli at 3 days, increased at 14 days, but decreased at 2 months. These cells lacked reactivity with antipodocalyxin in double immunofluorescence (IF) staining. In immunoelectron microscopy of a glomerulus on day 3 and 7, however, reaction products were observed within cells located on the outer surface of the GBM, which were considered to be podocyte in terms of its localization. In conclusion, we have shown a possibility that damaged podocytes partly constitute crescent-forming cells with phenotypic changes, visualized by positive staining with mAb OS-3. We propose a novel concept of crescent formation, suggesting that crescents may be partly composed of phenotypically changed cells, which could not be detected by typical markers for glomerular epithelial cells or monocytes/macrophages. [source] Moisture-induced effects on stacking strength of moulded-fibre packaging in varying environmental conditionsPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2004Gitte Sørensen Abstract Stacking strength of moulded-fibre trays was investigated as both compressional creep and static compression strength at constant and varying humidity conditions. The compressional creep behaviour resembled that of other paper and board containers and was accelerated at humidity cycling between 33% and 94% relative humidity (r.h.) for 18 days compared to constant humidity conditions 91% and 94% r.h. Although the moulded-fibre trays did not experience failure, secondary creep rate was accelerated by a factor of 10,20 and total creep strain by a factor of 1.3,1.6. Compressional creep was thus affected by mechanosorption, whereas static compression was found not to respond to cycling of environmental humidity. Static compression strength was merely determined by the moisture content of the moulded-fibre material. The effect of varying temperature on tray moisture content was examined by transfer of the moulded-fibre tray from preconditioning at cold storage (5°C, 59% r.h.) to ambient conditions (25°C, 54%). When a food simulant [agar gel, water activity (aw) ,1] was sealed inside the moulded-fibre tray, moisture condensed on the tray outer surface (moisture gain 1.4,g/100,g dry fibre) within 40,min of transfer, contrary to when empty moulded-fibre trays were exposed to same conditions. Condensation could thus potentially induce a large initial creep deformation of the moulded-fibre tray. Copyright © 2004 John Wiley & Sons, Ltd. [source] Experiments on single levitated particles: a novel approach for investigations of electronic properties of structured II-VI-semiconductor nanoparticles in selected environmentsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2007C. Graf Abstract A novel approach for investigations of the electronic structure of II-VI semiconductor nanoparticles in selected environments is presented. CdSe/ZnS core shell nanoparticles are dispersed in a liquid non-volatile siloxane graft/block copolymer and injected in an electrodynamic trap, where a single liquid microdroplet is stably stored under ultra high vacuum conditions. In this way, it is possible to investigate quantum dots by soft X-ray spectroscopies in a liquid environment, which is not influenced by any outer surface. NEXAFS spectra of stored nanoparticles were recorded at the Zn 2p-, S 2p-, and Cd 3d-edge by measuring X-ray excited optical luminescence or the element-selective charging current of single, trapped microdroplets. The spectra are compared to those of similar CdSe/ZnS nanoparticles, which are dispersed in a controlled way in solid silica colloids as well as to those of matrix materials. An analysis of the data reveals that the electronic structure of the ZnS shell is significantly influenced by the outer functionalization and the dispersive media whereas the electronic structure of the core is shown to be independent from the surroundings. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||||||||