54 research outputs found

    Molecular cytogenetic mapping of Cucumis sativus and C. melo using highly repetitive DNA sequences

    Get PDF
    Chromosomes often serve as one of the most important molecular aspects of studying the evolution of species. Indeed, most of the crucial mutations that led to differentiation of species during the evolution have occurred at the chromosomal level. Furthermore, the analysis of pachytene chromosomes appears to be an invaluable tool for the study of evolution due to its effectiveness in chromosome identification and precise physical gene mapping. By applying fluorescence in situ hybridization of 45S rDNA and CsCent1 probes to cucumber pachytene chromosomes, here, we demonstrate that cucumber chromosomes 1 and 2 may have evolved from fusions of ancestral karyotype with chromosome number n= 12. This conclusion is further supported by the centromeric sequence similarity between cucumber and melon, which suggests that these sequences evolved from a common ancestor. It may be after or during speciation that these sequences were specifically amplified, after which they diverged and specific sequence variants were homogenized. Additionally, a structural change on the centromeric region of cucumber chromosome 4 was revealed by fiber-FISH using the mitochondrial-related repetitive sequences, BAC-E38 and CsCent1. These showed the former sequences being integrated into the latter in multiple regions. The data presented here are useful resources for comparative genomics and cytogenetics of Cucumis and, in particular, the ongoing genome sequencing project of cucumbe

    Orbital anastomoses of the anterior deep temporal artery

    Full text link
    The anterior deep temporal artery may provide a major collateral pathway to the intracranial circulation through anastomoses with branches of the ophthalmic artery. Review of carotid angiograms in 26 patients with internal carotid artery occlusive disease revealed anterior deep temporal to ophthalmic artery anastomoses in 16 cases. This route of collateral blood flow was associated in most instances with total occlusion of the cervical portion of the internal carotid artery. Three cases demonstrating the angiographic anatomy of the anterior deep temporal artery and its potential anastomoses with branches of the ophthalmic artery are presented. L'artère temporale profonde antérieure peut être à l'origine de circulation colatérale grâce à ses anastomoses avec l'artère ophtalmique. Une telle anastomose a été constatée 16 fois sur 26 cas de thrombose de l'artère carotide interne. Über die A. temporalis anterior ist über Anastomosen zu den Ästen der A. ophthalmica ein Kollateral-Kreislauf zu den intracraniellen Gefäßabschnitten möglich. Bei 26 Patienten mit einem A. carotis interna-Verschluß zeigte sich dieser Kreislauf in 16 Fällen. Es wird über 3 Fälle ausführlich berichtet, bei denen die angiographische Anatomie der A. temporalis anterior und die möglichen Anastomosen mit Ästen der A. ophthalmica besprochen wird.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46672/1/234_2004_Article_BF00335020.pd

    CANDELS : constraining the AGN-merger connection with host morphologies at z ~ 2

    Get PDF
    Using Hubble Space Telescope/WFC3 imaging taken as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, we examine the role that major galaxy mergers play in triggering active galactic nucleus (AGN) activity at z ~ 2. Our sample consists of 72 moderate-luminosity (L X ~ 1042-44 erg s-1) AGNs at 1.5 < z < 2.5 that are selected using the 4 Ms Chandra observations in the Chandra Deep Field South, the deepest X-ray observations to date. Employing visual classifications, we have analyzed the rest-frame optical morphologies of the AGN host galaxies and compared them to a mass-matched control sample of 216 non-active galaxies at the same redshift. We find that most of the AGNs reside in disk galaxies (51.4+5.8 - 5.9%), while a smaller percentage are found in spheroids (27.8+5.8 - 4.6%). Roughly 16.7+5.3 - 3.5% of the AGN hosts have highly disturbed morphologies and appear to be involved in a major merger or interaction, while most of the hosts (55.6+5.6 - 5.9%) appear relatively relaxed and undisturbed. These fractions are statistically consistent with the fraction of control galaxies that show similar morphological disturbances. These results suggest that the hosts of moderate-luminosity AGNs are no more likely to be involved in an ongoing merger or interaction relative to non-active galaxies of similar mass at z ~ 2. The high disk fraction observed among the AGN hosts also appears to be at odds with predictions that merger-driven accretion should be the dominant AGN fueling mode at z ~ 2, even at moderate X-ray luminosities. Although we cannot rule out that minor mergers are responsible for triggering these systems, the presence of a large population of relatively undisturbed disk-like hosts suggests that the stochastic accretion of gas plays a greater role in fueling AGN activity at z ~ 2 than previously thought

    Dust in Supernovae and Supernova Remnants II: Processing and survival

    Get PDF
    Observations have recently shown that supernovae are efficient dust factories, as predicted for a long time by theoretical models. The rapid evolution of their stellar progenitors combined with their efficiency in precipitating refractory elements from the gas phase into dust grains make supernovae the major potential suppliers of dust in the early Universe, where more conventional sources like Asymptotic Giant Branch (AGB) stars did not have time to evolve. However, dust yields inferred from observations of young supernovae or derived from models do not reflect the net amount of supernova-condensed dust able to be expelled from the remnants and reach the interstellar medium. The cavity where the dust is formed and initially resides is crossed by the high velocity reverse shock which is generated by the pressure of the circumstellar material shocked by the expanding supernova blast wave. Depending on grain composition and initial size, processing by the reverse shock may lead to substantial dust erosion and even complete destruction. The goal of this review is to present the state of the art about processing and survival of dust inside supernova remnants, in terms of theoretical modelling and comparison to observations

    Optimal Localization and Image Fusion for DSA/CT/MRI using Leksell Frame

    No full text
    Optimal Localization is needed to remove the hazard generated in patient treatment through distortion correction, automatic detection method for fiduciary markers and target tumor

    Low-power, deformable, dynamic multicolor electrochromic skin

    No full text
    Active camouflage exhibited by certain creatures in nature such as cephalopods has inspired the fabrication of display devices for human-adaptive camouflage technologies. In order to realize that, electrochromic devices (ECDs) have attracted significant attention owing to their low-voltage operations and fast responses. However, the effective utilization of ECDs requires multicolor patterning, durable functioning, and wearable characteristics, simultaneously, but has not been explored. Here, we demonstrate a low-power, deformable, dynamic multicolor electrochromic skin (DMECS) that mimics the multicolor patterning and the active camouflage functionalities of the skins of cephalopods. The electrochromic polymers such as poly(3-hexylthiophene-2,5-diyl), poly[2-methoxy-5-(2-ethylhexyl-oxy)-1,4-phenylenevinylene], and P4a (green color polymer) are used to create purple, orange, and green colors, respectively. An iontronic polymer pump composed of an ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) incorporated in thermoplastic polyurethane is used as a deformable and transparent solid-state electrolyte that enables low-voltage (+/- 3 V) operated DMECS with excellent cyclic coloration/bleaching stability (>35,000 s), fast response (similar to 1.75 s), and high durability under repeated 10,000 cycles of compressive force (with a bending radius of 8 mm) and tensile strains (similar to 100% up to 15,000 s). We believe that our DMECS can offer user-controlled selective coloration/bleaching of arbitrary display patterns and open new avenues for next-generation wearable optoelectronics.11Nsciescopu

    Accuracy evaluation of blood flow distribution in the Fontan circulation: effects of resolution and velocity noise

    No full text
    This study analyzes the accuracy of the Fontan circulation using four-dimensional (4D) flow magnetic resonance imaging (MRI) for a variety of spatial resolution and noise scenarios. Using the results of computational fluid dynamics (CFD) as ground truth, hemodynamics in twelve patient-specific Fontan circulations were simulated as 4D flow MRIs, for voxel sizes of 0.5-3.0mm and noise levels of 0.1-50cm/s. In each case, three-dimensional streamline tracers were emitted at 1000 randomly sampled points from the inferior vena cava and superior vena cava planes, and the blood flow distribution from the vena cava to pulmonary arteries was quantified. The error of the flow distribution in 4D flow MRI was obtained by substituting the value obtained from 4D flow MRI into that obtained from CFD. Increasing the voxel size in 4D flow MRI affected the accuracy of the flow distribution estimation. The 4D flow MRI assessment of the flow distribution ratio in Fontan patients (2-4years old) had the errors of0.057,+/- 0.145 and +/- 0.210 at the voxel sizes of 1.0mm, 2.0mm, and 3.0mm, respectively. Increasing velocity noise increased the missing fraction of the tracers, increasing the mean error of the flow distribution ratio to 0.490 at the missing fractions above 70%. Using the missing fraction of 20% as a cutoff condition for the dataset, the error ratio in the analysis was confined to +/- 0.2. Assessment of the flow distribution using 4D flow MRI is sensitive to spatial resolution and velocity noise levels.11Nsciescopu
    corecore