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Stem
Kinds of Stem Terms modified by Stem Selected AbstractsCHARACTERIZATION OF CORAL RED SLIPS ON GREEK ATTIC POTTERY,ARCHAEOMETRY, Issue 3 2009M. S. WALTON Samples of red and black gloss from Greek Attic pottery of the late sixth to fifth centuries bc were examined using scanning electron microscopy (SEM and FIB/STEM). The focus of the study was the chemical and microstructural characterization of the red gloss that was first produced during this period. Two groupings of red gloss were revealed. One red was found to be compositionally similar to the black glosses (labelled ,LCM coral red'). The other red showed more significant chemical differences, such as higher calcium and magnesium, in comparison to the black (labelled ,HCM coral red'). The existence of two chemically distinct reds,otherwise identical in colour and texture,suggests that there was more than one source of clay available to the Attic potters for producing red. [source] Improved-Performance Dye-Sensitized Solar Cells Using Nb-Doped TiO2 Electrodes: Efficient Electron Injection and TransferADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Xujie Lü Abstract Well-crystallized Nb-doped anatase TiO2 nanoparticles are prepared by a novel synthetic route and successfully used as the photoanode of dye-sensitized solar cells (DSSCs). The homogenous distribution of Nb in the TiO2 lattice is confirmed by scanning transmission electron microscopy (STEM) elemental mapping and line-scanning analyses. After Nb doping, the conductivity of the TiO2 powder increases, and its flat-band potential (Vfb) has a positive shift. The energy-conversion efficiency of a cell based on 5.0,mol% Nb-doped TiO2 is significantly better, by about 18.2%, compared to that of a cell based on undoped TiO2. The as-prepared Nb-doped TiO2 material is proven in detail to be a better photoanode material than pure TiO2, and this new synthetic approach using a water-soluble precursor provides a simple and versatile way to prepare excellent photoanode materials. [source] Direct Determination of Dopant Site Selectivity in Ordered Perovskite CaCu3Ti4O12 Polycrystals by Aberration-Corrected STEMADVANCED MATERIALS, Issue 8 2009Si-Young Choi Through a combination of aberration-corrected HAADF-STEM and the EELS at the atomic level, it is found that added La in CaCu3Ti4O12 is selectively substituted for Ca, rather than Cu. The present study suggests that imaging based on STEM combined with EELS can be utilized as a powerful tool that reveals the atomic-level distribution of cation dopants in complex oxides. [source] A comparative study of the self-efficacy beliefs of successful men and women in mathematics, science, and technology careersJOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 9 2008Amy L. Zeldin Abstract The purpose of this study was to explore the personal stories of men who selected careers in science, technology, engineering, or mathematics (STEM) to better understand the ways in which their self-efficacy beliefs were created and subsequently influenced their academic and career choices. Analysis of 10 narratives revealed that mastery experience was the primary source of the men's self-efficacy beliefs. These results are compared to those from Zeldin and Pajares' earlier study involving women in STEM careers. For women, social persuasions and vicarious experiences were the primary sources of self-efficacy beliefs. Together, these findings suggest that different sources are predominant in the creation and development of the self-efficacy beliefs of men and women who pursue STEM careers. The self-efficacy beliefs of men in these male-dominated domains are created primarily as a result of the interpretations they make of their ongoing achievements and successes. Women, on the other hand, rely on relational episodes in their lives to create and buttress the confidence that they can succeed in male-dominated domains. Findings were consistent with the theoretical tenets of A. Bandura's social cognitive theory. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 1036,1058, 2008 [source] Self-definition of women experiencing a nontraditional graduate fellowship program,JOURNAL OF RESEARCH IN SCIENCE TEACHING, Issue 8 2006Gayle A. Buck Women continue to be underrepresented in the fields of science, technology, engineering, and mathematics (STEM). One factor contributing to this underrepresentation is the graduate school experience. Graduate programs in STEM fields are constructed around assumptions that ignore the reality of women's lives; however, emerging opportunities may lead to experiences that are more compatible for women. One such opportunity is the Graduate Teaching Fellows in K,12 Education (GK,12) Program, which was introduced by the National Science Foundation in 1999. Although this nontraditional graduate program was not designed explicitly for women, it provided an unprecedented context in which to research how changing some of the basic assumptions upon which a graduate school operates may impact women in science. This exploratory case study examines the self-definition of 8 women graduate students who participated in a GK,12 program at a major research university. The findings from this case study contribute to higher education's understanding of the terrain women graduate students in the STEM areas must navigate as they participate in programs that are thought to be more conducive to their modes of self-definition while they continue to seek to be successful in the historically Eurocentric, masculine STEM fields. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 852,873, 2006 [source] TEM/STEM Observation of ZrC Coating Layer for Advanced High-Temperature Gas-Cooled Reactor Fuel, Part IIJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2009Jun Aihara The Japan Atomic Energy Agency (JAEA) has started to study and develop zirconium carbide (ZrC)-coated fuel particles for advanced high-temperature gas-cooled reactors. The ZrC coating layer has been fabricated at JAEA by chemical vapor deposition using a pyrolytic reaction of zirconium bromide. The microstructures of the ZrC layers, whose nominal deposition temperatures could be measured and controlled during the deposition process, were characterized by means of TEM and STEM. In the present study, three batches were prepared and compared with each other as well as the previous batches. The crystallographic orientation of ZrC with regard to the growth direction in the ZrC layers deposited at a constant temperature of 1630 K was different from that deposited at varying temperatures in the 1493,1823 K range. A thin layer of turbostratic carbon was observed at the boundary between pyrolytic carbon and ZrC in particles deposited at the highest temperature among those used in this study (the nominal temperature was 1769 K); no such structure was found in a batch deposited at a lower temperature (the nominal temperature was 1632 K). Therefore, precise control of temperature is shown to be critical to the formation of good ZrC coatings. [source] Quantitative X-Ray Spectrum Imaging of Lead Lanthanum Zirconate Titanate PLZT Thin-FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2008Chad M. Parish The high permittivity of Pb(Zr,Ti)O3 and (Pb,La)(Zr,Ti)O3,PZT and PLZT, respectively,thin films and the flexibility of chemical solution deposition (CSD) make solution-derived P(L)ZT thin films extremely attractive for integrated capacitor applications. However, Pb-loss or cation segregation during processing results in degraded properties of the final film. Here, we have extended the use of multivariate statistical analysis (MSA) of energy-dispersive spectroscopy (EDS) spectrum images (SIs) in scanning transmission electron microscopy (STEM) to allow the two-dimensional (2D) quantitative analysis of cation segregation and depletion in P(L)ZT thin films. Quantified STEM-EDS SIs allow high-resolution (< ,10 nm) quantification of these cation distributions. Surface Pb depletion is found after crystallization and is replenished by a unique post-crystallization PbO overcoat+anneal processes. Zr/Ti and La segregation are found to develop in a decidedly nonplanar fashion during crystallization, especially in PLZT 12/70/30 material, highlighting the need for 2D analysis. Quantitative 2D chemical information is essential for improved processing of homogeneous P(L)ZT films with optimal electrical properties. [source] Effects of minor additions and impurities on oxidation behaviour of FeCrAl alloys.MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 12 2005Development of novel surface coatings compositions Abstract In the present work the effects of single or combined minor additions of Zr, Hf, Ti and C on the oxidation behaviour of Y-containing, FeCrAl alloys have been studied. For this purpose high-purity, model alloys with single or multiple minor alloying additions were used. The results of long term discontinuous oxidation tests and detailed kinetics studies using thermogravimetry were complemented with extensive microstructural characterisation of the formed alumina scales using SEM and STEM. Hence, the oxidation kinetics and scale spallation rates and failure modes were correlated with the oxide composition and microstructure. The results demonstrate that the frequently reported positive effect of Zr, Hf and Ti on the lifetime oxidation behaviour of FeCrAl alloys can only be fully exploited if the concentrations of the above elements are carefully adjusted and the interaction with typical alloy impurities, such as carbon, is considered. [source] Nanometric crystal defects in transmission electron microscopyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 5 2006Robin Schäublin Abstract Transmission electron microscopy (TEM) is revisited in order to define methods for the identification of nanometric defects. Nanometric crystal defects play an important role as they influence, generally in a detrimental way, physical properties. For instance, radiation-induced damage in metals strongly degrades mechanical properties, rendering the material stronger but brittle. The difficulty in using TEM to identify the nature and size of such defects resides in their small size. TEM image simulations are deployed to explore limits and possible ways to improve on spatial resolution and contrast. The contrast of dislocation loops, cavities, and a stacking fault tetrahedra (SFT) are simulated in weak beam, interfering reflections (HRTEM), and scanned condensed electron probe (STEM) mode. Results indicate that STEM is a possible way to image small defects. In addition, a new objective aperture is proposed to improve resolution in diffraction contrast. It is investigated by simulations of the weak beam imaging of SFT and successfully applied in experimental observations. Microsc. Res. Tech. 69:305,316, 2006. © 2006 Wiley-Liss, Inc. [source] Stranski,Krastanow growth of stacked GaN quantum dots with intense photoluminescencePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2003K. Hoshino Abstract Multiple-layer stacked GaN quantum dots (QDs) with intense photoluminescence (PL) have been grown by the Stranski,Krastanow growth mode in metalorganic chemical vapor deposition. Scanning transmission electron microscopy (STEM) analysis shows that the vertical aligned QDs are formed, which results from a strain field induced by buried islands. We have also investigated PL spectra at room temperature. The PL intensity increases with increasing number of the stacked layer. This indicates that the carriers can be injected into each layer of GaN quantum dots. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of convergent beam semiangle on image intensity in HAADF STEM imagesACTA CRYSTALLOGRAPHICA SECTION A, Issue 1 2010Koji Kuramochi In this study, we experimentally and theoretically show that the intensities of bright spots in a spherical aberration (Cs)-uncorrected high-angle annular dark-field (HAADF) scanning transmission electron microscope (STEM) image of [011]-oriented Co3O4, which has two different numbers of Co atoms in the projected atomic columns, are reversed with increasing sample thickness. However, Cs -corrected HAADF STEM images produce intensities that correctly depend on the average number of atoms in the projected atomic columns. From an analysis based on the Bloch-wave theorem, it is found that an insufficient semiangle of the incident convergent beam yields intensities that do not depend on the average atomic number in the atomic columns. [source] Extended dynamical HAADF STEM image simulation using the Bloch-wave methodACTA CRYSTALLOGRAPHICA SECTION A, Issue 4 2006Takashi Yamazaki An extended method is proposed for the precise simulation of high-angle annular dark-field (HAADF) scanning transmission electron-microscope (STEM) images for materials containing elements with large atomic numbers and for thick specimens. The approach combines a previously reported method utilizing two kinds of optical potential [Watanabe, Yamazaki, Hashimoto & Shiojiri (2001). Phys. Rev. B, 64, 115432] with a representation of a crystal sliced into multiple layers. The validity of the method is demonstrated by simulated images for elements with the diamond structure (Si, Ge and ,-Sn) and for the perovskite BaTiO3. [source] Magnetically Separable Gold Catalyst for the Aerobic Oxidation of AminesCHEMCATCHEM, Issue 1 2009Linda Aschwanden Abstract A magnetically separable, recyclable gold catalyst consisting of gold nanoparticles supported on intimately mixed superparamagnetic ceria/iron oxide has been prepared by simple addition of the preformed mixed oxide support and the gold precursor, Au(OAc)3, to the reaction mixture of the aerobic oxidation of amines. The catalyst was characterized by means of X-ray diffraction (XRD), N2 adsorption, superconducting quantum-interference device (SQUID) measurements, time-of-flight secondary ion mass spectrometry (TOF-SIMS), scanning transmission electron microscopy (STEM), and scanning electron microscopy with an energy-dispersive X-ray spectrometer (SEM-EDAX). Catalytic tests with various amines showed high selectivity to the corresponding imines (87,100,%), and good separation efficiency and recyclability of the catalyst. [source] Rational Design of Ag/TiO2 Nanosystems by a Combined RF-Sputtering/Sol-Gel ApproachCHEMPHYSCHEM, Issue 18 2009Lidia Armelao Dr. Abstract The present work is devoted to the preparation of Ag/TiO2 nanosystems by an original synthetic strategy, based on the radio-frequency (RF) sputtering of silver particles on titania-based xerogels prepared by the sol,gel (SG) route. This approach takes advantage of the synergy between the microporous xerogel structure and the infiltration power characterizing RF-sputtering, whose combination enables the obtainment of a tailored dispersion of Ag-containing particles into the titania matrix. In addition, the system,s chemico-physical features can be tuned further through proper ex situ thermal treatments in air at 400 and 600,°C. The synthesized composites are extensively characterized by the joint use of complementary techniques, that is, X-ray photoelectron and X-ray excited Auger electron spectroscopies (XPS, XE-AES), secondary ion mass spectrometry (SIMS), glancing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FE,SEM), transmission electron microscopy (TEM), electron diffraction (ED), high-angle annular dark field scanning TEM (HAADF,STEM), energy-filtered TEM (EF,TEM) and optical absorption spectroscopy. Finally, the photocatalytic performances of selected samples in the decomposition of the azo-dye Plasmocorinth B are preliminarily investigated. The obtained results highlight the possibility of tailoring the system characteristics over a broad range, directly influencing their eventual functional properties. [source] Origin of Anomalous Pt,Pt Distances in the Pt/Alumina Catalytic SystemCHEMPHYSCHEM, Issue 12 2004Karl Sohlberg Prof. Intriguing Pt3structures observed on the Pt/,-alumina catalytic system by atomic-resolution Z -contrast scanning transmission electron microscopy (STEM) are investigated with first-principles calculations (see electronic densities in the Pt3 plane with and without the capping OH group). [source] Oxide layer dissolution in Si/SiOx/Si wafer bonded structuresCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2009N. Zakharov Abstract The evolution of the interfaces of hydrophilic-bonded Si wafers and the corresponding low-angle twist boundary have been analysed in relation to thermal annealing and their relative crystallographic orientation. Two orientation relationships were investigated: Si<001>/Si<001> and Si<001>/Si<110>, where the interfaces are seperated by thin native SiO2 layers. The interfaces were analysed by TEM and STEM/EELS. It is found that the decomposition rate of the intermediate oxide layer and the formation of a Si(Si bonded interface depend very much on the lattice mismatch and on the twist angle. The velocity of the dissolution of the thin oxide layers and the formation of Si(Si bonds at the bonding interface depend on the orientation relations of the corresponding wafers. The processes of interface fusion and the dissolution of oxide layer are discussed. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Extracerebellar progenitors grafted to the neurogenic milieu of the postnatal rat cerebellum adapt to the host environment but fail to acquire cerebellar identitiesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2010Chiara Rolando Abstract Stem or progenitor cells acquire specific regional identities during early ontogenesis. Nonetheless, there is evidence that cells heterotopically transplanted to neurogenic regions of the developing or mature central nervous system may switch their fate to adopt host-specific phenotypes. Here, we isolated progenitor cells from different germinative sites along the neuraxis where GABAergic interneurons are produced (telencephalic subventricular zone, medial ganglionic eminence, ventral mesencephalon and dorsal spinal cord), and grafted them to the prospective white matter of the postnatal rat cerebellum, at the time when local interneurons are generated. The phenotype acquired by transplanted cells was assessed by different criteria, including expression of region-specific transcription factors, acquisition of morphological and neurochemical traits, and integration in the cerebellar cytoarchitecture. Regardless of their origin, all the different types of donor cells engrafted in the cerebellar parenchyma and developed mature neurons that shared some morphological and neurochemical features with local inhibitory interneurons, particularly in the deep nuclei. Nevertheless, transplanted cells failed to activate cerebellar-specific regulatory genes. In addition, their major structural features, the expression profiles of type-specific markers and the laminar placement in the recipient cortex did not match those of endogenous interneurons generated during the same developmental period. Therefore, although exogenous cells are influenced by the cerebellar milieu and show remarkable capabilities for adapting to the foreign environment, they essentially fail to switch their fate, integrate in the host neurogenic mechanisms and adopt clear-cut cerebellar identities. [source] Anisogramma virgultorum on saplings of Betula pendula and Betula pubescens in a district of northern SwedenFOREST PATHOLOGY, Issue 4-5 2002J. WITZELL Summary During the autumn of 1999, the occurrence of the ascomycete Anisogramma virgultorum on saplings of Betula pubescens and Betula pendula was studied in two stands of B. pubescens, two stands of B. pendula and two mixed (B. pubescens and Pinus sylvestris) stands (age approximately 10 years, mean height 2,4 m, d.b.h. 10,20 mm) in a district in the vicinity of Umeå, northern Sweden. Stem and branch cankers associated with A. virgultorum were found on 54.8% of the investigated saplings, without significant difference between B. pendula and B. pubescens. Cankers were observed on 16.0% of stems and on branches of 54.2% of the saplings. Stem cankers appeared on the current year's shoot, as well as at the base of the trees. The mean diameter of the damaged saplings was significantly greater than the mean diameter of undamaged saplings. All samples of cankers with stromata examined in the laboratory showed perithecia with asci. Résumé Anisogramma virgultorum sur jeunes plants de Betula pendula et Betula pubescens dans un district du nord de la Suède Pendant l'été 1999, le développement de l'ascomycète Anisogramma virgultorum a étéétudié sur de jeunes plants de Betula pendula et Betula pubescens dans deux peuplements de B. pubescens, deux peuplements de B. pendula et deux peuplements mélangés (B. pubescens et Pinus sylvestris) (âge: environ 10 ans, hauteur moyenne: 2 à 4 m, dbh: 10 à 20 mm), dans un district près d'Umeå au nord de la Suède. Des chancres de tige et de branches associés àA. virgultorum ont été trouvés sur 54,8% des plants, sans différences significative entre B. pendula et B. pubescens. Les chancres de tige étaient présents sur 16% des plants, et les chancres de branches sur 54,2%. Les chancres de tige étaient situés sur les pousses de l'année en cours aussi bien qu'à la base des arbres. La diamètre moyen des plants attaqués était significativement plus grand que celui des arbres sains. Tous les chancres avec stromas examinés au laboratoire présentaient des périthèces avec des asques. Zusammenfassung Anisogramma virgultorum an Sämlingen von Betula pendula und Betula pubescens in einem Distrikt in Nordschweden Im Herbst 1999 wurde das Vorkommen des Ascomyceten Anisogramma virgultorum an Betula pubescens und Betula pendula in jeweils zwei Reinbeständen dieser Baumarten sowie in zwei Mischbeständen (B. pubescens und Pinus sylvestris) in einem Distrikt in der Nähe von Umeå, Nordschweden, untersucht (Alter ca. 10 Jahre, mittlere Baumhöhe 2,4 m, DBH 10,20 mm). Bei 54,8 % der untersuchten Bäumchen wurden an Stamm und Zweigen Krebse gefunden, die für A.virgultorum typisch sind. Zwischen B. pendula und B. pubescens gab es keine signifikanten Unterschiede. Bei 16 % der Pflanzen wurden Krebse an den Stämmen, bei 54,2 % an den Zweigen beobachtet. Die Stammkrebse traten sowohl am diesjährigen Gipfeltrieb auf als auch an der Stammbasis. Der mittlere Durchmesser geschädigter Pflanzen war signifikant grösser als derjenige von ungeschädigten Pflanzen. Alle Proben von Krebsen mit Stromata, die im Labor untersucht wurden, enthielten Perithecien mit Asci. [source] Radiofrequency Catheter Ablation of Idiopathic Ventricular Tachycardia Originating in the Main Stem of the Pulmonary ArteryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2002CARL TIMMERMANS M.D. Idiopathic Pulmonary Artery Ventricular Tachycardia. We report the case of a patient in whom successful radiofrequency catheter ablation of an idiopathic ventricular tachycardia (VT) originating in the main stem of the pulmonary artery was performed. After successful ablation of the index arrhythmia, which was an idiopathic right ventricular outflow tract VT, a second VT with a different QRS morphology was reproducibly induced. Mapping of the second VT revealed the presence of myocardium approximately 2 cm above the pulmonary valve. Application of radiofrequency energy at this site resulted in termination and noninducibility of this VT. After 6-month follow-up, the patient remained free from VT recurrences. [source] Location of Caspase 3-like Protease in the Development of Sieve Element and Tracheary Element of Stem in Cucurbita moschataJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2008Xia Hao Abstract The casepase is considered to regulate the process of programmed cell death in the development of organisms. In this study, caspase 3-like protease was detected by immunohistochemistry and immunoelectron microscopy during the development of sieve element and tracheary element of stem in Cucurbita moschata Duch. Antibody with brown color (under light microscopy) and gold particles (under transmission electron microscopy) for detecting caspase 3-like protease was mainly displayed in inner phloem, external phloem and xylem in the region close to procambium. From the results it was considered that caspase 3-like protease did exist in vascular elements and played different roles during the development of sieve and tracheary elements, and different types of programmed cell death might be carried out. The caspase 3-like protease mainly participated in making cytoplasmic streaming cease and in degrading P-protein bodies; however, it rarely participated in the function for signal transferring in the developmental sieve element. However, it might induce calcium accumulation for rupturing the tonoplast in the signal of PCD in the developmental tracheary element. [source] Stem cell-mediated accelerated bone healing observed with in vivo molecular and small animal imaging technologies in a model of skeletal injuryJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2009Sheen-Woo Lee Abstract Adult stem cells are promising therapeutic reagents for skeletal regeneration. We hope to validate by molecular imaging technologies the in vivo life cycle of adipose-derived multipotent cells (ADMCs) in an animal model of skeletal injury. Primary ADMCs were lentivirally transfected with a fusion reporter gene and injected intravenously into mice with bone injury or sham operation. Bioluminescence imaging (BLI), [18F]FHBG (9-(fluoro-hydroxy-methyl-butyl-guanine)-micro-PET, [18F]Fluoride ion micro-PET and micro-CT were performed to monitor stem cells and their effect. Bioluminescence microscopy and immunohistochemistry were done for histological confirmation. BLI showed ADMC's traffic from the lungs then to the injury site. BLI microscopy and immunohistochemistry confirmed the ADMCs in the bone defect. Micro-CT measurements showed increased bone healing in the cell-injected group compared to the noninjected group at postoperative day 7 (p,<,0.05). Systemically administered ADMC's traffic to the site of skeletal injury and facilitate bone healing, as demonstrated by molecular and small animal imaging. Molecular imaging technologies can validate the usage of adult adipose tissue-derived multipotent cells to promote fracture healing. Imaging can in the future help establish therapeutic strategies including dosage and administration route. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:295,302, 2009 [source] Ethanol Alters Cell Fate of Fetal Human Brain-Derived Stem and Progenitor CellsALCOHOLISM, Issue 9 2010Sharada D. Vangipuram Background:, Prenatal ethanol (ETOH) exposure can lead to fetal alcohol spectrum disorder (FASD). We previously showed that ETOH alters cell adhesion molecule gene expression and increases neurosphere size in fetal brain-derived neural stem cells (NSC). Here, our aim was to determine the effect of ETOH on the cell fate of NSC, premature glial-committed precursor cells (GCP), and premature neuron-committed progenitor cells (NCP). Methods:, NSC, GCP, and NCP were isolated from normal second-trimester fetal human brains (n = 3) by positive selection using magnetic microbeads labeled with antibodies to CD133 (NSC), A2B5 (GCP), or PSA-NCAM (NCP). As a result of the small percentage in each brain, NSC were cultured in mitogenic media for 72 hours to produce neurospheres. The neurospheres from NSC and primary isolates of GCP and NCP were used for all experiments. Equal numbers of the 3 cell types were treated either with mitogenic media or with differentiating media, each containing 0 or 100 mM ETOH, for 120 hours. Expression of Map2a, GFAP, and O4 was determined by immunoflourescence microscopy and western blot analysis. Fluorescence intensities were quantified using Metamorph software by Molecular Devices, and the bands of western blots were quantified using densitometry. Results:, ETOH in mitogenic media promoted formation of neurospheres by NSC, GCP, and NCP. Under control conditions, GCP attached and differentiated, NSC and NCP formed neurospheres that were significantly smaller in size than those in ETOH. Under differentiating conditions, Map2a expression increased significantly in NSC and GCP and reduced significantly in NCP, and GFAP expression reduced significantly in GCP and NCP, and Gal-C expression reduced significantly in all 3 cell types in the presence of ETOH compared to controls. Conclusions:, This study shows that ETOH alters the cell fate of neuronal stem and progenitor cells. These alterations could contribute to the mechanism for the abnormal brain development in FASD. [source] Trafficking of Murine Hematopoietic Stem and Progenitor Cells in Health and Vascular DiseaseMICROCIRCULATION, Issue 6 2009CHRISTIAN SCHULZ ABSTRACT Hematopoietic stem cells (HSCs) possess the unique capacity for self-renewal and differentiation into various hematopoietic cell lineages. Here we summarize the processes that underlie their mobilization and directed migration from bone marrow into peripheral tissues and back to the bone marrow compartment. We specifically focus on the potential role of hematopoietic stem and progenitor cell (HSPC) migration in vascular diseases and review data from recent studies on mice. A better understanding of the mechanisms that guide HSPCs to vascular tissues will be critical for the development of novel therapeutic strategies to prevent or reverse cardiovascular diseases. [source] Embryonic stem cells and prospects for their use in regenerative medicine approaches to motor neurone diseaseNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 5 2007Y. A. Christou Human embryonic stem cells are pluripotent cells with the potential to differentiate into any cell type in the presence of appropriate stimulatory factors and environmental cues. Their broad developmental potential has led to valuable insights into the principles of developmental and cell biology and to the proposed use of human embryonic stem cells or their differentiated progeny in regenerative medicine. This review focuses on the prospects for the use of embryonic stem cells in cell-based therapy for motor neurone disease or amyotrophic lateral sclerosis, a progressive neurodegenerative disease that specifically affects upper and lower motor neurones and leads ultimately to death from respiratory failure. Stem cell-derived motor neurones could conceivably be used to replace the degenerated cells, to provide authentic substrates for drug development and screening and for furthering our understanding of disease mechanisms. However, to reliably and accurately culture motor neurones, the complex pathways by which differentiation occurs in vivo must be understood and reiterated in vitro by embryonic stem cells. Here we discuss the need for new therapeutic strategies in the treatment of motor neurone disease, the developmental processes that result in motor neurone formation in vivo, a number of experimental approaches to motor neurone production in vitro and recent progress in the application of stem cells to the treatment and understanding of motor neurone disease. [source] Gene expression associated with N-induced shifts in resource allocation in poplarPLANT CELL & ENVIRONMENT, Issue 5 2003J. E. K. COOKE ABSTRACT Surprisingly little is known about molecular mechanisms by which nitrogen (N) availability acts to modulate the growth of forest trees. To address this issue, differential display was used in conjunction with filter-based arrays to identify 52 partial cDNA clones that were significantly regulated within days in response to limiting or luxuriant levels of NH4NO3 fertilization in Populus trichocarpa Torr. & Gray × deltoides Bartr. ex Marsh. A subset of these cDNAs also demonstrated shifts in expression patterns in stem-girdled trees, a manipulative physiology technique that disrupts phloem transport. Stem girdling also induced changes in glutamine and asparagine pools which were correlated with the observed changes in expression profiles for these genes. The identity of these genes provides insight into biochemical processes that are altered by N availability in poplar. Carbon,nitrogen interactions appear to figure prominently in the N-response. The gene expression data suggest that N availability modulates the partitioning of C and N resources into metabolic fates that have the potential to alter both wood quality and quantity, including synthesis of vegetative storage proteins, cell wall components, and terpenoids. [source] Remarkable Site Difference of Vibrational Energy Relaxation in Benzene Dimer: Picosecond Time-Resolved IR,UV Pump,Probe Spectroscopy,ANGEWANDTE CHEMIE, Issue 39 2010Ryoji Kusaka Ganz entspannt: Die Schwingungsenergierelaxation (VER) von Isotopologen des Benzol-Dimers auf dem C-H-Streckschwingungsniveau wurde durch zeitaufgelöste Pikosekunden-IR-UV-Pump-Sonden-Spektroskopie untersucht (siehe Bild, h=C6H6, d=C6D6). Dabei ergab sich ein bemerkenswerter Unterschied in den Relaxationslebensdauern: Die Lebenszeit des ,stehenden" Benzolmoleküls (,Stem", 110,ps) ist 4.5mal kürzer als die des ,liegenden" (,Top", 500,ps). [source] Hybrid Assembly of Metal Head and Femoral Stem From Different Manufacturers During Isolated Acetabular RevisionARTIFICIAL ORGANS, Issue 8 2010Cheng-Fong Chen Abstract During revision of a failed acetabular component with well-fixed antiquated femoral stem, the same variant of metal head is usually not available in the inventory production. We gathered the stems retrieved from revision surgeries and tried to reassemble with the commercially available femoral heads. This study reports the results of suitable hybrid assembly of metal heads with the most common antiquated femoral stems from different manufacturers. Three hybrid combinations were determined and pull-off strengths of these hybrid combinations were performed through in vitro studies to evaluate the quality of the taper locks. [source] Metaphyseal-Loading Anterolaterally-Flared Femoral Stem in Cementless Total Hip Arthroplasty: Five- to Eleven-Year Follow-Up EvaluationARTIFICIAL ORGANS, Issue 5 2010Hideo Kawahara Abstract Using a nonlinear three-dimensional finite element analysis simulating loading conditions, we designed a new type of proximal-fitting, anterolaterally-flared, arc-deposit hydroxyapatite-coated anatomical femoral stem (FMS-anatomic stem; Japan Medical Materials, Osaka, Japan) for cementless total hip arthroplasty (THA) for Japanese patients with dysplastic hip osteoarthritis. The aim of the present study was to analyze the clinical and radiographic outcomes of the new stem. We reviewed 143 consecutive patients (164 hips; 13 men, 14 hips; 130 women, 150 hips; age at surgery, 56.6 ± 7.6 years, mean ± SD, range, 30,74) who underwent cementless THA using the FMS-anatomic stem at a single institution, with a follow-up period of 7.6 ± 1.6 years (range, 5.3,11.0). Harris Hip score improved from 46.1 ± 12.6 before surgery to 90.0 ± 8.9 points post-THA. The 7.6-year survival rate of the stem was 99.0% after revision for aseptic loosening. Radiographs at follow-up confirmed the stability of the femoral stems within the femoral canal in all cases, with sufficient bone ingrowth. None of the patients had subsidence of the stem exceeding 2.0 mm within the femoral canal or changes in varus or valgus position of more than 2.0°. The FMS-anatomic stem provided excellent results in patients with dysplastic hip osteoarthritis. Our analysis confirmed reduced radiolucency around the stem in Gruen zones, minimal subsidence, appropriate stress shielding, and promising medium-term stability within the femoral canal in our patients. [source] Three Diterpenoids (Excoecarins V1,V3) and a Flavanone Glycoside from the Fresh Stem of Excoecaria agallocha.CHEMINFORM, Issue 12 2004Tenji Konishi No abstract is available for this article. [source] COSMOPOLITANISM, REMEDIATION, AND THE GHOST WORLD OF BOLLYWOODCULTURAL ANTHROPOLOGY, Issue 1 2010DAVID NOVAK ABSTRACT This essay considers the process of remediation in two North American reproductions of the song-and-dance sequence Jaan Pehechaan Ho from the 1965 "Bollywood" film Gumnaam. The song was used in the opening sequence of the 2001 U.S. independent film Ghost World as a familiar-but-strange object of ironic bewilderment and fantasy for its alienated teenage protagonist Enid. But a decade before Ghost World's release, Jaan Pehechaan Ho had already become the lynchpin of a complex debate about cultural appropriation and multicultural identity for an "alternative" audience in the United States. I illustrate this through an ethnographic analysis of a 1994 videotape of the Heavenly Ten Stems, an experimental rock band in San Francisco, whose performance of the song was disrupted by a group of activists who perceived their reproduction as a mockery. How is Bollywood film song, often itself a kitschy send-up of American popular culture, remediated differently for different projects of reception? How do these cycles of appropriation create overlapping conditions for new identities,whether national, diasporic, or "alternative",within the context of transcultural media consumption? In drawing out the "ghost world" of Bollywood's juxtapositions, I argue that the process of remediation produces more than just new forms and meanings of media, but is constitutive of the cosmopolitan subjects formed in its global circulations. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||