Hemoglobin-Mediated Nitric Oxide Signaling

The rate that hemoglobin reacts with nitric oxide (NO) is limited by how fast NO can diffuse into the heme pocket. The reaction is as fast as any ligand/protein reaction can be and the result, when hemoglobin is in its oxygenated form, is formation of nitrate in what is known as the dioxygenation reaction. As nitrate, at the concentrations made through the deoxygenation reaction, is biologically inert, the only role hemoglobin was once thought to play in NO signaling was to inhibit it. However, there are now several mechanisms that have been discovered by which hemoglobin may preserve, control, and even create NO activity. These mechanisms involve compartmentalization of reacting species and conversion of NO from or into other species such as nitros othiols or nitrite which could transport NO activity. Despite the tremendous amount of work devoted to this field, major questions concerning precise mechanisms of NO activity preservation as well as if and how Hb creates NO activity remain unanswered

Eye movement desensitization and reprocessing (EMDR) for the treatment of psychosis: a systematic review

Background: Psychosis is a public health concern. There is increasing evidence suggesting trauma can play a pivotal role in the development and maintenance of psychosis. Eye Movement Desensitization and Reprocessing (EMDR) is an effective treatment for trauma and could be a vital addition to the treatment of psychosis. Objective: To explore the evidence for EMDR as a treatment for psychosis, focussing on the safety, effectiveness and acceptability of this intervention for this population. Methods: Four databases (Cochrane, EMBASE, MEDLINE PsychINFO), and the Francine Shapiro Library were systematically searched, along with grey literature and reference lists of relevant papers. No date limits were applied as this is an area of emerging evidence. Studies were screened for eligibility based on inclusion and exclusion criteria. The included studies were quality assessed and data was extracted from the individual studies, and synthesized using a narrative synthesis approach. Results: Six studies met the inclusion criteria (1 RCT, 2 Pilot studies, 2 Case series and 1 Case report). Across the studies EMDR was associated with reductions in delusional and negative symptoms, mental health service and medication use. Evidence for reductions in auditory hallucinations and paranoid thinking was mixed. No adverse events were reported, although initial increases in psychotic symptoms were observed in two studies. Average dropout rates across the studies were comparable to other trauma-focused treatments for PTSD. The acceptability of EMDR was not adequately measured or reported. Conclusion: EMDR appears a safe and feasible intervention for people with psychosis. The evidence is currently insufficient to determine the effectiveness and acceptability of the intervention for this population. Larger confirmative trials are required to form more robust conclusions

Complete physical simulation of the entangling-probe attack on the BB84 protocol

We have used deterministic single-photon two qubit (SPTQ) quantum logic to implement the most powerful individual-photon attack against the Bennett-Brassard 1984 (BB84) quantum key distribution protocol. Our measurement results, including physical source and gate errors, are in good agreement with theoretical predictions for the Renyi information obtained by Eve as a function of the errors she imparts to Alice and Bob's sifted key bits. The current experiment is a physical simulation of a true attack, because Eve has access to Bob's physical receiver module. This experiment illustrates the utility of an efficient deterministic quantum logic for performing realistic physical simulations of quantum information processing functions.Comment: 4 pages, 5 figure

Generating Entangled Two-Photon States with Coincident Frequencies

It is shown that parametric downconversion, with a short-duration pump pulse and a long nonlinear crystal that is appropriately phase matched, can produce a frequency-entangled biphoton state whose individual photons are coincident in frequency. Quantum interference experiments which distinguish this state from the familiar time-coincident biphoton state are described.Comment: Revised version (a typo was corrected) as published on PR

Room Temperature Continuous Wave Lasing in Nanopillar Photonic Crystal Cavities

We demonstrate room temperature continuous wave lasing in bottom-up photonic crystal cavities formed by patterned III-V nanopillars. Single-cell high-Q photonic crystal cavities are formed with nanopillars by selective-area epitaxy. Control of the nanopillar geometry and heterostructures allows for high-Q and large confinement factor, resulting in a low threshold power density of 75 W/cm^2 at 1040 nm emission wavelength

The origin of intergalactic thermonuclear supernovae

The population synthesis method is used to study the possibility of explaining the appreciable fraction (20^+12_15%) of the intergalactic (no-host) type Ia supernovae observed in galaxy clusters (Gal-Yam ete al. 2003) by binary whote dwarf merginngs in the cores of globular clusters. In a typical globular cluster, the number of merging double white dwarfs is fount to be smaller than 10^{-13} per year per average cluster star during the entire evolution of the cluster, which is a factor of 3 higher than in a Milky-Way-type galaxy. From 5 to 30% of the merging white dwarfs are dynamically expelled from the cluster with barycenter velocities up to 150 km/s. SN Ia explosions during the mergers of binary white dwarfs in dense star clusters may account for \sim 1% of the total rate of SN Ia in the central parts of galaxy clusters if the baryon mass fraction in such star clusters is \sim 0.3%.Comment: 8 pages, 3 figs. Astronomy Letters (in press

Hologrphy and holographic dark energy model

The holographic principle is used to discuss the holographic dark energy model. We find that the Bekenstein-Hawking entropy bound is far from saturation under certain conditions. A more general constraint on the parameter of the holographic dark energy model is also derived.Comment: no figures, use revtex, v2: use iop style, some typos corrected and references updated, will appear in CQ

Measuring the elements of the optical density matrix

Most methods for experimentally reconstructing the quantum state of light involve determining a quasiprobability distribution such as the Wigner function. In this paper we present a scheme for measuring individual density matrix elements in the photon number state representation. Remarkably, the scheme is simple, involving two beam splitters and a reference field in a coherent state.Comment: 6 pages and 1 figur

Intrinsic Decoherence Dynamics in Smooth Hamiltonian Systems: Quantum-classical Correspondence

A direct classical analog of the quantum dynamics of intrinsic decoherence in Hamiltonian systems, characterized by the time dependence of the linear entropy of the reduced density operator, is introduced. The similarities and differences between the classical and quantum decoherence dynamics of an initial quantum state are exposed using both analytical and computational results. In particular, the classicality of early-time intrinsic decoherence dynamics is explored analytically using a second-order perturbative treatment, and an interesting connection between decoherence rates and the stability nature of classical trajectories is revealed in a simple approximate classical theory of intrinsic decoherence dynamics. The results offer new insights into decoherence, dynamics of quantum entanglement, and quantum chaos.Comment: 12 pages, 7 figures, to appear in Physical Review

Mechanisms of Hemolysis-Associated Platelet Activation

Background Intravascular hemolysis occurs after blood transfusion, in hemolytic anemias, and in other conditions, and is associated with hypercoagulable states. Hemolysis has been shown to potently activate platelets in vitro and in vivo, and several mechanisms have been suggested to account for this, including: (i) direct activation by hemoglobin (Hb); (ii) increase in reactive oxygen species (ROS); (iii) scavenging of nitric oxide (NO) by released Hb; and (iv) release of intraerythrocytic ADP. Objective To elucidate the mechanism of hemolysis-mediated platelet activation. Methods We used flow cytometry to detect PAC-1 binding to activated platelets for in vitro experiments, and a Siemens\u27 Advia 120 hematology system to assess platelet aggregation by using platelet counts from in vivo experiments in a rodent model. Results We found that Hb did not directly activate platelets. However, ADP bound to Hb could cause platelet activation. Furthermore, platelet activation caused by shearing of red blood cells (RBCs) was reduced in the presence of apyrase, which metabolizes ADP to AMP. The use of ROS scavengers did not affect platelet activation. We also found that cell-free Hb enhanced platelet activation by abrogating the inhibitory effect of NO on platelet activation. In vivo infusions of ADP and purified (ADP-free) Hb, as well as hemolysate, resulted in platelet aggregation, as shown by decreased platelet counts. Conclusion Two primary mechanisms account for RBC hemolysis-associated platelet activation: ADP release, which activates platelets; and cell-free Hb release, which enhances platelet activation by lowering NO bioavailability