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  • 1
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    Joint quantum-state and measurement tomography with incomplete measurements (2018)
    American Physical Society (APS)
    Details
    Publication Date: 2018-10-13
    Description: Author(s): Adam C. Keith, Charles H. Baldwin, Scott Glancy, and E. Knill Estimation of quantum states and measurements is crucial for the implementation of quantum information protocols. The standard method for each is quantum tomography. However, quantum tomography suffers from systematic errors caused by imperfect knowledge of the system. We present a procedure to simu... [Phys. Rev. A 98, 042318] Published Fri Oct 12, 2018
    Keywords: Quantum information
    Print ISSN: 1050-2947
    Electronic ISSN: 1094-1622
    Topics: Physics
    Published by American Physical Society (APS)
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    PAPER CURRENT
  • 2
    Electronic Resource
    Electronic Resource
    Sites of Tubulin Polymerization in PC 12 Cells (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 54 (1990), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The site at which tubulin enters into polymer in the neuritic process is a very important datum in terms of our understanding of the mechanism of transport of the microtubular cytoskeleton out the axon. If the form of tubulin being transported out the axon is the microtubule, then assembly of tubulin into microtubules should occur at or near the cell body; if, however, the form of tubulin transported is free tubulin dimer, then assembly can occur at any free microtubule end out the neurite. We have injected a fluorescent analog of tubulin into differentiated PC12 cells and used differential extraction protocols to extract free dimer but not microtubules. We have imaged these cells before and after extraction by low-light-level video fluorescence microscopy and have used image analysis to examine the sites of tubulin incorporation into polymer or other unextracted components as a function of time. We find that tubulin in the distal reaches of the neurite is found initially as monomer and that its appearance in the unextracted component occurs later. This pattern of appearance of fluorescent tubulin initially in the soluble fraction and later in the unextractable component is qualitatively similar to that reported by other workers for biotinylated tubulin, but we see a larger gap between the rates of appearance in soluble fraction and in polymer. Quantitative analysis of fluorescence intensities in the two compartments with distance out the neurite reveals substantial variation between different neurites: In some neurites, the pattern of variation of unextracted/total tubulin suggests that tubulin enters into the unextracted component primarily near the cell body and that this unextracted component moves out the neurite with time, and in other neurites it suggests that monomer adds onto microtubule ends staggered out the neurite. In no case do we see a pattern suggesting that distal addition predominates. These analyses of fluorescence intensities in extracted and unextracted neurites suggest that both transport of polymerized microtubules and monomer addition onto staggered microtubule ends occur in PC12 neurites and that in individual neurites one or the other of these two behaviors may predominate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1990.tb01957.x
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  • 3
    Electronic Resource
    Electronic Resource
    Trypanosoma cruzi Infection of BSC-1 Fibroblast Cells Causes Cytoskeletal Disruption and Changes in Intracellular Calcium Levels (1992)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 39 (1992), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The disruption of vimentin and actin filaments of host BSC-1 fibroblast cells by Trypanosoma cruzi was investigated using a mouse monoclonal anti-vimentin antibody and rhodamine phalloidin, respectively. Indirect immunofluorescence microscopy demonstrated that infection of BSC-1 cells by T. cruzi caused disruption of both cytoskeletal components. The disruption was greater as infection progressed. Mechanisms other than mechanical ones may play a role in the disruption since disrupted cytoskelelal elements were well removed from the parasites. In the determination of intracellular calcium concentrations using Fura-2 AM, infected and uninfected cells both showed an initial increase in intracellular calcium levels. At later times of infection (3 to 5 days), intracellular calcium levels of infected cells were significantly lower than those of control cells. There was no specific localization of intracellular calcium in the infected host cells as determined by image analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1992.tb04833.x
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  • 4
    Electronic Resource
    Electronic Resource
    A Monoclonal Antibody to Alpha Tubulin Recognizes Host Cell and Trypanosoma cruzi Tubulins (1988)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 35 (1988), S. 0 
    Details
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . A mouse monoclonal anti-α-tubulin antibody was used to investigate the disposition of the cytoskeletal microtubules of three tissue culture cell lines–J774 macrophages, BSC-1, and Vero cells–infected with the Brazil strain of Trypanosoma cruzi. Indirect immunofluorescence light microscopy was used to demonstrate the antigenic response in host cells and parasites, simultaneously. In all morphotypes of T. cruzi, the monoclonal antibody reacted with all subpopulations of microtubules, inclusively, the subpellicular, flagellar, cytopharyngeal, and mitotic. The host cell cytoskeletal microtubule framework was revealed and the redistribution and destruction of the microtubular lattice in response to parasite infection over a 120 h period recorded. Our results show that after the initial inoculation of tissue cultures with trypomastigotes, the parasites penetrate the cells and locate in the perinuclear region of the cell where they multiply. The number and distribution of host cell microtubules were altered during the infection. The normal radial distribution of microtubules extending from the center of the cell to the periphery was destroyed. The remaining microtubules were observed at the periphery encircling, but well removed from the proliferating parasites. The complete transformation of the parasites was monitored throughout the infection with the end result being the liberation of parasites and the near complete destruction of the microtubular framework of the host cell. A residual population of dividing spheromastigotes was observed in cells liberating trypomastigotes. Colloidal gold labeling of thin sections as seen in the electron microscope affirmed the specificity of our monoclonal antibody to all subpopulations of microtubules in T. cruzi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1550-7408.1988.tb04091.x
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  • 5
    Electronic Resource
    Electronic Resource
    Nitrogen Oxides in Tobacco Smoke (1965)
    [s.l.] : Nature Publishing Group
    Nature 205 (1965), S. 915-916 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Although NO and NO2 are both readily absorbed in the human lung, their physiological action is reported to be quite different. NO is found to be approximately five times less toxic than NO2 (ref. 5), and recently it has been found that NO is approximately six times less active as a mammalian ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/205915b0
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  • 6
    Electronic Resource
    Electronic Resource
    Local cytoplasmic calcium gradients in living mitotic cells (1985)
    [s.l.] : Nature Publishing Group
    Nature 316 (1985), S. 848-850 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Localization of calcium at the mitotic spindle poles of endosperm cells during mitosis, a, Bright-field image of a cell in anaphase; 6, c, the same cell observed with 340 and 360 nm excitation after loading with Quin-2; d, the /340//360 ratio calculated at each point and redisplayed as an ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/316848a0
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  • 7
    Electronic Resource
    Electronic Resource
    Microtubule behavior in PC12 neurites: Variable results obtained with photobleach technology (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 345-357 
    Details
    ISSN: 0886-1544
    Keywords: fluorescent analogue cytochemistry ; cytoskeletal transport ; photobleach technology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have examined the effects of various means of photobleaching on the recovery of fluorescene, movement, and morphology of the microtubules in the neurites of rhodamine-tubulin-injected PC12 cells. We find that, depending on power of and time of exposure to the bleaching beam, we can generate at least three different patterns of fluorescence recovery in regenerating PC12 neurites. If bleaching is performed with a relatively low-power beam for an extended period, fluorescence in polymer recovers very little after 1 hours. Under these conditions, however, tubulin immunostaining is seen extending through the bleach zone, and microtubules are present through the bleached zone in thin section electron micrographs. If bleaching is performed with a high-power laster, for 0.5-5 seconds, fluorescence recovery also is quite slow, but electron microscopic observations reveal that no microtubules extend through the bleached region of the neurite, and the uranyl acetate-stained cytoplasm appears more electron lucent than in the unbleached neurite. Finally, if bleaching is performed by very brief exposure to a high-intensity laser beam, resulting in an incomplete reduction of fluorescence intensity through the bleach zone, fluorescence recovery occurs within 20-30 minutes, and immunostained microtubules appear intact through the bleach zone; electron microscopy confirms that microtubules extended through the bleached zone of such neurites. In all three cases, movement of the bleach zone is observed in approximately half of the experimental neurites. These results indicate that highly variable microtubule behaviors can be obtained with photobleach technology, presumably due to different levels and pathways of photodamage generated by different bleach protocols. Nevertheless, it is clear that both turnover and movement of microtubules occur in FC12 neurites, and both are likely to be involved in neurite maintenance and growth. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250405
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  • 8
    Electronic Resource
    Electronic Resource
    Neurite elongation is blocked if microtubule polymerization is inhibited in PC12 cells (1990)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 95-105 
    Details
    ISSN: 0886-1544
    Keywords: colchicine-tubulin ; neurite growth ; process extension ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have injected process-bearing PC12 cells with colchicine-tubulin mixed with either fluorescein-dextran or a rhodamine-labelled tubulin analogue to determine the role of microtubule polymerization in neurite elongation. Colchicine-tubulin is a specific, substoichiometric poison of microtubule assembly. We have shown that colchicine-tubulin does not cause existing PC12 microtubules to disassemble, and yet can inhibit the assembly of rhodamine-tubulin injected along with it. In population s'udies of neurite outgrowth in injected and uninjected cells, we find that colchicine-tubulin substantially inhibits neurite extension from injected cells over a wide variety of concentrations. In acute time-course studies of injected cells, we find that colchicine-tubulin does not block neurite outgrowth until the injectate reaches the neurite tip. Thereafter, however, it blocks process elongation completely. Thus we can conclude that microtubule polymerization in the region of the growth cone is an important element in neurite elongation. While polymerization at the cell body may be important in supplying subunits to the distal neurite, it does not play a direct role in process extension.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970170205
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of microinjectecd calcium-calmodulin on mitosis in PtK2 cells (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 1-9 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; calcium ; calmodulin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Calcium and calmodulin are believed in play a significant role in the regulation of mitosis, because they are both localized in the mitotic spindle and because they can potentiate microtubule depolymerization in the test tube and in the living cell. It has been hypothesized, specifically, that calcium-saturated calmodulin drives the shortening of the kinetochore microtubules that must occur during prometaphase, when the chromosomes congress to the metaphase plate, and during anaphase A, when the half-spindles shorten. We have examined the role of calmodulin in mitosis by observing the consequences of calmodulin microinjection on the progress of mitosis and morphology of the mitotic spindle in PtK2 cells. We have found that the injection of excess calcium-saturated calmodulin during early prometaphase significantly prolongs the time required for the cell to go into anaphase, and that neither calcium-depleted calmodulin nor buffer alone produce a similar perturbation. Calcium ion alone produces a similar but much smaller retardation of mitosis. Immunofluorescence and fluorescent analogue cytochemical studies of spindle morphology reveal that the immediate (〈5-min) effect of calcium-saturated calmodulin on prometaphase spindles is a significant shortening of the kinetochore fibers and “interpolar” microtubules but not the astral microtubules. After this perturbation, however, the spindle quickly recovers its normal form. An equivalent transient shortening of the spindle fibers is seen following the injection of calcium chloride solutions but not after the injection of calciumdepleted calmodulin or buffer alone. Taken together, these observations suggest that calcium-saturated calmodulin plays a significant role in the regulation of mitosis, and that this regulatory pathway involves more than spindle fiber shortening.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070102
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  • 10
    Electronic Resource
    Electronic Resource
    Loss of α2-macroglobulin and epidermal growth factor surface binding induced by phenothiazines and naphthalene sulfonamides (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 118 (1984), S. 193-202 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have found that certain naphthalenesulfonamides [e.g., N-6(-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7)] and phenothiazines [e.g., trifluoperazine (TFP)] induce a loss of cell-surface receptors for α2-macroglobulin and epidermal growthfactor (EGF) in fibroblasts. The loss of α2-macroglobulin receptors is independent of receptor occupancy and is rapidly reversed upon removal of these agents from the culture medium. The extent of EGF receptor loss is less than for α2-macroglobulin, and the EGF receptors do not reappear at the surface when W-7 isremoved. Receptor loss was measured as a change in the capacity for binding iodinated ligands;nochange in affinity of binding was observed. This receptor loss could reflect inactivation of receptors or internalization. W-7 did not induce a loss of cell surface β2-microglobulin, a membrane protein which is excluded from coated pits and which isnot internalized, indicating that the effect of W-7 was specific for membrane receptorsandnot a result of bulk depletion of plasma membrane. The loss of α2-macroglobulin and EGF receptors occurs at concentrations which do not cause an increase in the pH of endocytic vesicles or the cytoplasm, indicating that these agents act by a mechanism distinct from the effect of other weak bases. Since both TFP and W-7 are potent inhibitors of calmodulin, we investigated the possibility that inhibition of calmodulin was responsiblefor the loss of receptors. Three lines of evidence suggest that calmodulin inhibition is not responsible for the inhibition of binding and endocytosis: (1) Promethazine, a phenothiazine that is a poor inhibitor of calmodulin, is nearly as effective as TFP at inhibiting endocytosis; calmidazolium, a potent inhibitor of several calmodulin functions, did not cause a loss of binding; (2) the microinjection of calmodulin into cells did not reverse the effects of W-7; using pressure microinjection, we introduced up to a 100-fold excess of calmodulin over native levels into individual gerbil fibroma cells; using rho-damine-labeled α2-macroglobulln, we saw that the W-7 induced inhibition of receptor-mediated endocytosis was the same in injected and uninjected cells; (3) we injected calcineurin, a calmodulin-binding protein, into cells (1-3 pg/ cell) and observed no effect on the receptor-mediated endocytosis of rhoda-mine-labeled α2-macroglobulin. These data indicated that cell surface receptor numbers can be regulated by a cellular component that is not cytoplasmic calmodulin but that shares some drug sensitivities with calmodulin.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041180212
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