1,665 research outputs found

    An Analytic Theory for the Orbits of Circumbinary Planets

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    Isolated foetal ascites.

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    The prenatal diagnosis and perinatal outcome of two patients with isolated foetal ascites compatible with chyloperitoneum is described. The foetal ascites resolved spontaneously after delivery with good perinatal outcome in both cases. A good prognosis can be anticipated in such cases. Antepartum and intrapartum interventions are seldom necessary.published_or_final_versio

    Is syndrome X related to antiogensin-converting enzyme gene polymorphism?

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    Synthesis and properties of ZnO nano-ribbon and comb structures

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    ZnO is of great interest for photonic applications due to its wide band gap (3.37 eV) and large exciton binding energy (60 meV). A large variety of fabrication methods and nanostructure morphologies was reported up to date for this material. Obtained morphologies include nanobelts or nanoribbons, nanowires, nanorods, tetrapod nanostructures, etc. Novel nanostructures like hierarchical nanostructures, nanobridges and nanonails have also been fabricated. In this work, we report a simple method for fabrication of nanoribbon and nanocomb structures. The structures are fabricated by evaporation of a mixture of ZnO and carbon nanotubes (CNT) at 1050Ā°C, and the deposition products have been collected on Si substrates in the temperature range 750-800Ā°C. The growth mechanism of obtained structures is discussed. Ā© 2005 American Institute of Physics.published_or_final_versio

    Sox10 regulates enteric neural crest cell migration in the developing gut

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    Concurrent Sessions 1: 1.3 - Organs to organisms: Models of Human Diseases: abstract no. 1417th ISDB 2013 cum 72nd Annual Meeting of the Society for Developmental Biology, VII Latin American Society of Developmental Biology Meeting and XI Congreso de la Sociedad Mexicana de Biologia del Desarrollo. The Conference's web site is located at http://www.inb.unam.mx/isdb/Sox10 is a HMG-domain containing transcription factor which plays important roles in neural crest cell survival and differentiation. Mutations of Sox10 have been identified in patients with Waardenburg-Hirschsprung syndrome, who suffer from deafness, pigmentation defects and intestinal aganglionosis. Enteric neural crest cells (ENCCs) with Sox10 mutation undergo premature differentiation and fail to colonize the distal hindgut. It is unclear, however, whether Sox10 plays a role in the migration of ENCCs. To visualize the migration behaviour of mutant ENCCs, we generated a Sox10NGFP mouse model where EGFP is fused to the N-terminal domain of Sox10. Using time-lapse imaging, we found that ENCCs in Sox10NGFP/+ mutants displays lower migration speed and altered trajectories compared to normal controls. This behaviour was cell-autonomous, as shown by organotypic grafting of Sox10NGFP/+ gut segments onto control guts and vice versa. ENCCs encounter different extracellular matrix (ECM) molecules along the developing gut. We performed gut explant culture on various ECM and found that Sox10NGFP/+ ENCCs tend to form aggregates, particularly on fibronectin. Time-lapse imaging of single cells in gut explant culture indicated that the tightly-packed Sox10 mutant cells failed to exhibit contact inhibition of locomotion. We determined the expression of adhesion molecule families by qPCR analysis, and found integrin expression unaffected while L1-cam and selected cadherins were altered, suggesting that Sox10 mutation affects cell adhesion properties of ENCCs. Our findings identify a de novo role of Sox10 in regulating the migration behaviour of ENCCs, which has important implications for the treatment of Hirschsprung disease.postprin

    The clinical course of polymyalgia rheumatica in Chinese

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    Polymyalgia rheumatica (PMR) is diagnosed based on clinical features that may overlap with other rheumatic conditions like rheumatoid arthritis (RA). Furthermore, a proportion of PMR patients may subsequently evolve into RA. The aim of this study was to examine the clinical characteristics of PMR patients in a Chinese cohort compared to a Caucasian series. Patients diagnosed to have PMR during 1997-2008 were reviewed for clinical features and compared to a reported Caucasian series. Rheumatoid factor (RF) and anticyclic citrullinated peptide (CCP) antibodies were determined by immunonephelometry and enzyme-linked immunosorbent assay, respectively. Forty-four patients of southern Chinese origin were diagnosed to have PMR according to specialist opinion. Seventy-five percent of patients (n = 33) were >65 years of age at diagnosis (mean Ā± standard deviation, 75.8 Ā± 9.6 years). The commonest feature at disease onset was elevated erythrocyte sedimentation rate >40 mm/h (100% vs. 95.7%; p = 0.17) and bilateral shoulder pain or stiffness (95.5% vs. 90.8%; p = 0.31), comparable in frequency to the Caucasian cohort. However, Chinese patients had significantly longer duration of symptoms before diagnosis (p < 0.001) but less bilateral upper arm tenderness (p < 0.001) and generalized stiffness (p = 0.01). Twelve (27.3%) patients evolved into RA after a median duration of 2 months from onset of PMR. RF and anti-CCP antibodies were positive in 66.7% and 60% of these patients compared to 9.4% and 6.2%, respectively, among those who did not evolve into RA during the period observed. Chinese patients with PMR have modestly different clinical profile compared to the Caucasian counterpart. RF and anti-CCP antibodies were more likely to be present in those who subsequently developed into RA. Ā© 2009 Clinical Rheumatology.postprin

    Cyp26b1 mediates differential regulation of RA signaling in neural progenitor populations along the anteriorposterior axis of the adult spinal cord

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    Poster Session - Neural Regeneration: no. 64DMM 2011 entitled: Re-engineering Regenerative MedicineNeural stem cells from the adult subventricular zone (SVZ) are highly heterogeneous, with their position of origin being a key factor in determining the neuronal subtype they can give rise to. Whether this diversity extends to other regions in the adult CNS has not been demonstrated. In vitro studies with directed neuronal differentiation of ES cells suggest that subtype specification may be regulated by the positional identity present in the ESā€derived cell, since altering the positional identity leads to corresponding changes in motor neuron subtype. This limited plasticity suggests the position identity of the original stem cell source is a critical factor for the generation of the desired neuronal subtype. The adult spinal cord consists of endogenous stem/progenitor cells which are ā€¦postprin

    Cyp26b1 mediates differential neurogenicity in axial-specific populations of adult spinal cord progenitor cells

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    Utilization of endogenous adult spinal cord progenitor cells (SCPCs) for neuronal regeneration is a promising strategy for spinal cord repair. To mobilize endogenous SCPCs for injury repair, it is necessary to understand their intrinsic properties and to identify signaling factors that can stimulate their neurogenic potential. In this study, we demonstrate that adult mouse SCPCs express distinct combinatorial Hox genes and exhibit axial-specific stem cell properties. Lumbar-derived neurospheres displayed higher primary sphere formation and greater neurogenicity compared with cervical- and thoracic-derived neurospheres. To further understand the mechanisms governing neuronal differentiation of SCPCs from specific axial regions, we examined the neurogenic responses of adult SCPCs to retinoic acid (RA), an essential factor for adult neurogenesis. Although RA is a potent inducer of neuronal differentiation, we found that RA enhanced the generation of neurons specifically in cervical- but not lumbar-derived cells. We further demonstrate that the differential RA response was mediated by the RA-degrading enzyme cytochrome P450 oxidase b1 Cyp26b1. Lumbar cells express high levels of Cyp26b1 and low levels of the RA-synthesizing enzyme retinaldehyde dehydrogenase Raldh2, resulting in limited activation of the RA signaling pathway in these cells. In contrast, low Cyp26b1 expression in cervical spinal cord progenitor cells allows RA signaling to be readily activated upon RA treatment. The intrinsic heterogeneity and signaling factor regulation among adult SCPCs suggest that different niche factor regimens are required for site-specific mobilization of endogenous SCPCs from distinct spatial regions of the spinal cord for injury repair.published_or_final_versio

    Growth of N, Nā€²-di(naphthalene-1-yl)-N, Nā€²-diphenyl-benzidine dome structures

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    N,Nā€²-di(naphthalene-1-yl)-N,Nā€²-diphenyl-benzidine samples exhibiting interesting nano/microstructure were fabricated by thermal evaporation in a tube furnace under Ar gas flow. We investigated the influence of the substrate type, substrate temperature, source temperature, and the gas flow rate on the obtained morphology. The deposited material was investigated using scanning electron microscopy, x-ray diffraction, and photoluminescence. We found that the substrate temperature was the factor which significantly affected the obtained morphology, while other factors such as substrate type, source temperature, and gas flow mainly affected the size distribution of the features but not the type of morphology observed. Ā© 2005 American Institute of Physics.published_or_final_versio

    Formation of core/shell structured cobalt/carbon nanoparticles by pulsed laser ablation in toluene

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    Author name used in this publication: H. Y. KwongAuthor name used in this publication: M. H. WongAuthor name used in this publication: C. W. LeungAuthor name used in this publication: Y. W. WongAuthor name used in this publication: K. H. Wong2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
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