Nondiffracting beams for vortex tomography

We propose a reconstruction of vortex beams based on the implementation of quadratic transformations in the orbital angular momentum. The information is encoded in a superposition of Bessel-like nondiffracting beams. The measurement of the angular probability distribution at different positions allows for the reconstruction of the Wigner function.Comment: 3 pages. 2 eps figures. To appear in Optics Letter

Gamma-Interferon-Induced Nitric-Oxide Production Reduces Chlamydia-Trachomatis Infectivity in McCoy Cells

McCoy cells, murine-derived cells commonly used for propagation of chlamydiae, were found to be efficient producers of nitric oxide (NO) when primed with murine gamma interferon (IFN-gamma) and then exposed to the second signals provided by Escherichia coli lipopolysaccharide, human interleukin-1 alpha, murine tumor necrosis factor alpha, or Chlamydia trachomatis type H. Murine recombinant IFN-gamma over a range of 0 to 50 U/ml inhibited infectivity of C. trachomatis type H in a dose-dependent fashion in McCoy cells while simultaneously inducing NO production. Quantitation of infectious chlamydia progeny remaining in McCoy cells 48 or 72 h postinfection revealed that IFN-gamma-primed McCoy cells reduced chlamydial inclusion-forming units (expressed as units per milliliter) by 4 log10 units at higher IFN-gamma concentrations (50 U/ml) compared with control values. The magnitude of this antichlamydial effect was directly related to increased synthesis of NO, the production of which was IFN-gamma dose dependent. The antichlamydial effects of IFN-gamma were blocked in a dose-dependent manner by the addition of N-guanidino-monomethyl L-arginine (MLA), an inhibitor of nitric oxide synthesis. These results suggest that although IFN-gamma priming of McCoy cells is required for antichlamydial activity, nitric oxide is a necessary effector molecule involved in the mechanism(s) of IFN-gamma-induced inhibition of chlamydial proliferation in this murine cell line. The ability to block the potent antichlamydial effects of IFN-gamma by inhibition of a specific enzyme, nitric oxide synthase, may give insights into mechanisms by which IFN-gamma and perhaps other cytokines are able to control proliferation of chlamydiae and other intracellular pathogens

Regulation of dopamine transporter activity by carboxypeptidase E

<p>Abstract</p> <p>Background</p> <p>The dopamine transporter (DAT) plays a critical role in terminating the action of dopamine by rapid reuptake into the presynaptic neuron. Previous studies have revealed that the DAT carboxyl terminus (DAT-CT) can directly interact with other cellular proteins and regulate DAT function and trafficking.</p> <p>Results</p> <p>Here, we have identified that carboxypeptidase E (CPE), a prohormone processing exopeptidase and sorting receptor for the regulated secretory pathway, interacts with the DAT-CT and affects DAT function. Mammalian cell lines coexpressing CPE and DAT exhibited increased DAT-mediated dopamine uptake activity compared to cells expressing DAT alone. Moreover, coexpression of an interfering DAT-CT minigene inhibited the effects of CPE on DAT. Functional changes caused by CPE could be attributed to enhanced DAT expression and subsequent increase in DAT cell surface localization, due to decreased DAT degradation. In addition, CPE association could reduce the phosphorylation state of DAT on serine residues, potentially leading to reduced internalization, thus stabilizing plasmalemmal DAT localization.</p> <p>Conclusion</p> <p>Taken together, our results reveal a novel role for CPE in the regulation of DAT trafficking and DAT-mediated DA uptake, which may provide a novel target in the treatment of dopamine-governed diseases such as drug addiction and obesity.</p

Electrochemical evidence of catalysis of oxygen reduction at the polarized liquid–liquid interface by tetraphenylporphyrin monoacid and diacid

Cyclic voltammetry is used to study the role of 5,10,15,20-tetraphenyl-21H,23H-porphine (H2TPP) in the reduction of molecular oxygen by decamethylferrocene (DMFc) at the polarized water|1,2-dichloroethane (DCE) interface. It is shown that this rather slow reaction proceeds remarkably faster in the presence of tetraphenylporphyrin monoacid (H3TPP+) and diacid (H4TPP2+), which are formed in DCE by the successive transfer of two protons from the acidified aqueous phase. A mechanism is proposed, which includes the formation of adduct between H3TPP+ or H4TPP2+ and O2 that is followed by electron transfer from DMFc to the adduct leading to the observed production of DMFc+ and to the regeneration of H2TPP or H3TPP+, respectively

Tool-assisted rhythmic drumming in palm cockatoos shares key elements of human instrumental music

All human societies have music with a rhythmic &ldquo;beat,&rdquo; typically produced with percussive instruments such as drums. The set of capacities that allows humans to produce and perceive music appears to be deeply rooted in human biology, but an understanding of its evolutionary origins requires cross-taxa comparisons. We show that drumming by palm cockatoos (Probosciger aterrimus) shares the key rudiments of human instrumental music, including manufacture of a sound tool, performance in a consistent context, regular beat production, repeated components, and individual styles. Over 131 drumming sequences produced by 18 males, the beats occurred at nonrandom, regular intervals, yet individual males differed significantly in the shape parameters describing the distribution of their beat patterns, indicating individual drumming styles. Autocorrelation analyses of the longest drumming sequences further showed that they were highly regular and predictable like human music. These discoveries provide a rare comparative perspective on the evolution of rhythmicity and instrumental music in our own species, and show that a preference for a regular beat can have other origins before being co-opted into group-based music and dance