Resonance-continuum interference in the di-photon Higgs signal at the LHC

A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg -> H -> gamma gamma, with the continuum QCD background, gg -> gamma gamma induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg -> gamma gamma scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.Comment: 10 pages, 2 figure

Non-equilibrium phase transition in a sheared granular mixture

The dynamics of an impurity (or tracer particle) immersed in a dilute granular gas under uniform shear flow is investigated. A non-equilibrium phase transition is identified from an exact solution of the inelastic Boltzmann equation for a granular binary mixture in the tracer limit, where the impurity carries either a vanishing (disordered phase) or a finite (ordered phase) fraction of the total kinetic energy of the system. In the disordered phase, the granular temperature ratio (impurity "temperature" over that of the host fluid) is finite, while it diverges in the ordered phase. To correctly capture this extreme violation of energy equipartition, we show that the picture of an impurity enslaved to the host fluid is insufficient

Broken symmetries and directed collective energy transport

We study the appearance of directed energy current in homogeneous spatially extended systems coupled to a heat bath in the presence of an external ac field E(t). The systems are described by nonlinear field equations. By making use of a symmetry analysis we predict the right choice of E(t) and obtain directed energy transport for systems with a nonzero topological charge Q. We demonstrate that the symmetry properties of motion of topological solitons (kinks and antikinks) are equivalent to the ones for the energy current. Numerical simulations confirm the predictions of the symmetry analysis and, moreover, show that the directed energy current drastically increases as the dissipation parameter $\alpha$ reduces. Our results generalize recent rigorous theories of currents generated by broken time-space symmetries to the case of interacting many-particle systems.Comment: 4 pages, 2 figure

Organometallic iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis

Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands

Driven diffusion in a periodically compartmentalized tube: homogeneity versus intermittency of particle motion

We study the effect of a driving force F on drift and diffusion of a point Brownian particle in a tube formed by identical ylindrical compartments, which create periodic entropy barriers for the particle motion along the tube axis. The particle transport exhibits striking features: the effective mobility monotonically decreases with increasing F, and the effective diffusivity diverges as F → ∞, which indicates that the entropic effects in diffusive transport are enhanced by the driving force. Our consideration is based on two different scenarios of the particle motion at small and large F, homogeneous and intermittent, respectively. The scenarios are deduced from the careful analysis of statistics of the particle transition times between neighboring openings. From this qualitative picture, the limiting small-F and large-F behaviors of the effective mobility and diffusivity are derived analytically. Brownian dynamics simulations are used to find these quantities at intermediate values of the driving force for various compartment lengths and opening radii. This work shows that the driving force may lead to qualitatively different anomalous transport features, depending on the geometry design

Obeticholic acid, a FXR agonist, inhibits the cancerogenic potential of primary human cholangiocarcinoma (CCA) cells cultures

Background and Aims: Cholangiocarcinoma is an aggressive cancer, resistant to chemotherapeutics. We demonstrated that CCA is enriched of cancer stem cells associated with aggressiveness and drug resistance. FXR, involved in neoplastic transformation of stem cells and/or cholangiocytes, is down-regulated in human CCA. Our AIM was to evaluate, in primary cultures of human intrahepatic CCA (iCCA) the effects of the FXR agonist, obeticholic acid (OCA), on the cancerogenic potential of human CCA cells. Method: Primary human cell cultures were prepared from specimens of iCCA obtained from patients submitted to surgical resection and classified into mucin- or mixed-iCCA subtypes by morphologic and immunohistochemical criteria. Increasing concentrations (0–5 μM) of OCAwere added to culture media and, after 3–10 days, the effect on proliferation (MTS assay, cell population doubling time), apoptosis (annexin V-FITC / propidium iodide), cell migration and invasion (wound healing and matrigel invasion assay) and cancerogenic potential (spheroid formation, clonogenic assay, colony formation capacity) were evaluated. Results: FXR was downregulated (RT-qPCR) in iCCA cells vs normal human biliary tree stem cells (p < 0.001) and in mucin-iCCA vs mixed-iCCA (p < 0.05). OCA significantly (p < 0.05) inhibited proliferation of both mucin-iCCA and mixed-iCCA cells starting at a concentration as low as 0.05 μM (IC50 = 0.38 μM in mixed- and 2.1 μM in mucin-iCCA). Also CDCA (but not UDCA) inhibited cell proliferation, although to a much lower extent than OCA, consistent with the different potency in FXR activation (i.e. OCA > CDCA, no agonistic effect for UDCA). OCA significantly induced apoptosis of both iCCA subtypes and decreased the in vitro cancerogenic potential of iCCA cells as evaluated by impairment of colony and spheroid formation capacity and delayed wound healing and matrigel invasion. In general, these effects were more evident against mixed- than mucin-iCCA cell. When tested together with gemcitabine and cisplatin, OCA potentiated the anti-proliferative and pro-apoptotic effects of these chemotherapeutics but mainly on mixed-iCCA. OCA abolished the capacity of both mucin- and mixed-iCCA cells to form colonies when administered together with gemcitabine and cisplatin

Current tick control strategies and prospects for using nanotechnology as an efficient alternative.

Ticks pose significant challenges to public and veterinary health, acting as vectors of several diseases that affect animals and humans. Traditional chemical control methods, such as pyrethroids and organophosphates, have led to increasing resistance and environmental contamination, highlighting the need and urgency for alternative strategies. This review explores contemporary approaches to tick control, emphasizing plant-derived acaricides and their integration with nanotechnology. Plant extracts, known for their acaricidal properties, disrupt several biological processes in ticks, reducing reproduction and survival rates. The advent of nanotechnology offers promising advances in increasing the efficacy of these natural extracts. Nanoparticles add properties to the systems where they act by improving the stability, bioavailability, and targeted delivery of plant-derived compounds, potentially overcoming the limitations of traditional acaricides. This synthesis of current knowledge highlights the potential of combining plant extracts with nanotechnology to develop sustainable and effective tick control solutions, addressing issues of acaricide resistance as well as environmental concerns. The review also identifies research gaps and suggests directions for future studies to optimize the application of nanotechnology in tick management