Early clearance of hairy cell leukaemia in the bone marrow after first-line treatment with cladribine predicts a favourable outcome.

First-line purine nucleoside analogues (PNAs) in hairy cell leukaemia (HCL) allow deep and long-lasting responses. We retrospectively analysed 53 HCL patients treated frontline with cladribine and assessed for response at 2 and 6 months after treatment to evaluate the kinetics of response. The estimated median progression-free survival was significantly different according to the degree of residual HCL infiltrate detected by immunohistochemistry at the bone marrow biopsy at 2 months (≤5% vs. >5%, 247 vs. 132 months, respectively, p = 0.033), but not at 6 months (p = 0.79). Our data suggest a favourable prognostic impact of early marrow HCL clearance in patients treated with cladribine.

Antithrombotic secondary prophylaxis with low dose of apixaban or rivaroxaban in the onco-hematologic patients: comparison with non-neoplastic patients.

Management of cancer-associated thrombosis (CAT) is usually performed employing low molecular weight heparin (LMWH) or direct oral anticoagulants (DOACs). Low-intensity DOACs are the mainstay for extended duration therapy for VTE in non-oncologic patients. The aim of our study was to evaluate the efficacy and the safety of low doses of apixaban or rivaroxaban as secondary prophylaxis in patients affected by hematological malignancies with follow-up > 12 months. We report an observational, retrospective, single-center study that evaluated consecutive patients referred to our center between January 2016 and January 2023. The DOACs were administered at full dose during the acute phase of VTE and then at low dose for the extended phase. We included 154 patients: 53 patients affected by hematological malignancies compared to 101 non-neoplastic patients. During full-dose treatment, no thrombotic recurrences were observed in the two groups. During low-dose therapy, 2 (1.9%) thrombotic events (tAE) were observed in the control group. During full-dose treatment, the rate of bleeding events (bAE) was 9/154 (5.8%): 6/53 (11%) in hematological patients and 3/101 (2.9%) in non-hematological patients (p = 0.0003). During low-dose therapy, 4/154 (2.6%) bAE were observed: 3/53 (5.5%) in the hematologic group and 1 (1%) in the control group (p = 0.07). We found encouraging data on the safety and efficacy of low doses of DOACs as secondary prophylaxis in the onco-hematologic setting; no thrombotic complications were observed, and the incidence of hemorrhagic events was low.

Waves in hyperbolic and double negative metamaterials including rogues and solitons.

The topics here deal with some current progress in electromagnetic wave propagation in a family of substances known as metamaterials. To begin with, it is discussed how a pulse can develop a leading edge that steepens and it is emphasised that such self-steepening is an important inclusion within a metamaterial environment together with Raman scattering and third-order dispersion whenever very short pulses are being investigated. It is emphasised that the self-steepening parameter is highly metamaterial-driven compared to Raman scattering, which is associated with a coefficient of the same form whether a normal positive phase, or a metamaterial waveguide is the vehicle for any soliton propagation. It is also shown that the influence of magnetooptics provides a beautiful and important control mechanism for metamaterial devices and that, in the future, this feature will have a significant impact upon the design of data control systems for optical computing. A major objective is fulfiled by the investigations of the fascinating properties of hyperbolic media that exhibit asymmetry of supported modes due to the tilt of optical axes. This is a topic that really merits elaboration because structural and optical asymmetry in optical components that end up manipulating electromagnetic waves is now the foundation of how to operate some of the most successful devices in photonics and electronics. It is pointed out, in this context, that graphene is one of the most famous plasmonic media with very low losses. It is a two-dimensional material that makes the implementation of an effective-medium approximation more feasible. Nonlinear non-stationary diffraction in active planar anisotropic hyperbolic metamaterials is discussed in detail and two approaches are compared. One of them is based on the averaging over a unit cell, while the other one does not include sort of averaging. The formation and propagation of optical spatial solitons in hyperbolic metamaterials is also considered with a model of the response of hyperbolic metamaterials in terms of the homogenisation ('effective medium') approach. The model has a macroscopic dielectric tensor encompassing at least one negative eigenvalue. It is shown that light propagating in the presence of hyperbolic dispersion undergoes negative (anomalous) diffraction. The theory is ten broadened out to include the influence of the orientation of the optical axis with respect to the propagation wave vector. Optical rogue waves are discussed in terms of how they are influenced, but not suppressed, by a metamaterial background. It is strongly discussed that metamaterials and optical rogue waves have both been making headlines in recent years and that they are, separately, large areas of research to study. A brief background of the inevitable linkage of them is considered and important new possibilities are discussed. After this background is revealed some new rogue wave configurations combining the two areas are presented alongside a discussion of the way forward for the future.

Rapid assessment of nonlinear optical propagation effects in dielectrics.

Ultrafast laser processing applications need fast approaches to assess the nonlinear propagation of the laser beam in order to predict the optimal range of processing parameters in a wide variety of cases. We develop here a method based on the simple monitoring of the nonlinear beam shaping against numerical prediction. The numerical code solves the nonlinear Schrödinger equation with nonlinear absorption under simplified conditions by employing a state-of-the art computationally efficient approach. By comparing with experimental results we can rapidly estimate the nonlinear refractive index and nonlinear absorption coefficients of the material. The validity of this approach has been tested in a variety of experiments where nonlinearities play a key role, like spatial soliton shaping or fs-laser waveguide writing. The approach provides excellent results for propagated power densities for which free carrier generation effects can be neglected. Above such a threshold, the peculiarities of the nonlinear propagation of elliptical beams enable acquiring an instantaneous picture of the deposition of energy inside the material realistic enough to estimate the effective nonlinear refractive index and nonlinear absorption coefficients that can be used for predicting the spatial distribution of energy deposition inside the material and controlling the beam in the writing process.

Harnessing optical vortex lattices in nematic liquid crystals.

By creating self-induced vortexlike defects in the nematic liquid crystal layer of a light valve, we demonstrate the realization of programable lattices of optical vortices with arbitrary distribution in space. On each lattice site, every matter vortex acts as a photonic spin-to-orbital momentum coupler and an array of circularly polarized input beams is converted into an output array of vortex beams with topological charges consistent with the matter lattice. The vortex arrangements are explained on the basis of light-induced matter defects of both signs and consistent topological rules.

All-optical switching of a signal by a pair of interacting nematicons.

We investigate a power tunable junction formed by two interacting spatial solitons self-trapped in nematic liquid crystals. By launching a counter-propagating copolarized probe we assess the guided-wave behavior induced by the solitons and demonstrate a novel all-optical switch. Varying soliton power the probe gets trapped into one or two or three guided-waves by the soliton-induced index perturbation, an effect supported by the nonlocal nonlinearity.

Vortex induction via anisotropy stabilized light-matter interaction.

By sending circularly polarized light beams onto a homeotropic nematic liquid crystal cell with a photosensitive wall, we are able to locally induce spontaneous matter vortices that remain, each, stable and trapped at the chosen location. We discuss the dual light-matter nature of the created vortices and demonstrate the ability of the system to create optical vortices with opposite topological charges that, consistent with angular momentum conservation, both derive from the same defect created in the liquid crystal texture. Theoretically, we identify a self-stabilizing mechanism for the matter vortex, which is provided by the concurrency of light-induced gradients and anisotropy of the elastic constants that characterize the deformation of the liquid crystal medium.

Dark nematicons.

We experimentally demonstrate and model dark spatial solitons in azo-doped liquid crystals, in the presence of saturation and nonlocality of the effective nonlinearity due to changes in molecular order. The guiding properties of dark solitons are probed with a weak input of different wavelength.

Enhancement of third-harmonic generation in nonlocal spatial solitons.

We report on the observation of Type I third-harmonic generation induced by a train of femtosecond laser pulses in nematic liquid crystals. We find that as the average power of the train is increased, the frequency conversion process is enhanced as a consequence of the tight confinement of the pulses into a nonlocal spatial soliton.

Random quasi-phase-matched second-harmonic generation in periodically poled lithium tantalate.

We observe second harmonic generation via random quasi-phase-matching in a 2.0 mum periodically poled, 1-cm-long, z-cut lithium tantalate. Away from resonance, the harmonic output profiles exhibit a characteristic pattern stemming from a stochastic domain distribution and a quadratic growth with the fundamental excitation, as well as a broadband spectral response. The results are in good agreement with a simple model and numerical simulations in the undepleted regime, assuming an anisotropic spread of the random nonlinear component.

Nematicon all-optical control in liquid crystal light valves.

We discuss the interactions between self-guided light beams and light-induced perturbations in a liquid crystal light valve. The model and data are in perfect agreement.

Spatial solitons in liquid-crystal light valves.

Liquid-crystal light valves can control the orientation of a nematic layer under the independent or combined action of applied voltage and impinging light intensity; hence, they offer a unique environment for the propagation of spatial optical solitons or nematicons. We demonstrate nematicon excitation, propagation, and steering in photoconductive light valves.

Near-infrared spatial solitons in heavy metal oxide glasses.

We demonstrate two-dimensional spatial solitons excited by near-infrared picosecond pulses in Kerr-like heavy metal oxide glasses with a nonlinearity one order of magnitude larger than in fused silica. Solitons were obtained at 820 nm owing to the presence of multiphoton absorption, which prevented catastrophic collapse.

Spatial solitons in nematic liquid crystals: from bulk to discrete.

We review theoretical and experimental results on spatial solitons in nematic liquid crystalline cells, including two-dimensional solitons in bulk and discrete solitons in one-dimensional waveguide arrays. In bulk we describe the propagation of continuous solitons in the presence of adjustable walk-off, their interaction with light-induced defects and refraction-reflection at a voltage-tunable interface. In optical lattices we address the transition from discrete diffraction to localization, as well as all-optical beam steering.

Self-healing generation of spatial solitons in liquid crystals.

We demonstrate that, in suitably designed cells with undoped nematic liquid crystals, extraordinary-wave spatial solitons can be excited at every applied voltage without adjustments in the input polarization. Their walk-off, hence direction of propagation, is externally controlled over angles as large as 7 degrees. The results pave the way not only to polarization-forgiving generation but also to voltage readdressing of these extraordinary-wave nematicons.

Terahertz pulse generation via optical rectification in photonic crystal microcavities.

Using a three-dimensional fully vectorial nonlinear time-domain analysis, we numerically investigate generation of terahertz radiation by pumping a photonic crystal microcavity out of resonance. High quality factors and a quadratic susceptibility lead to few-cycle terahertz pulses via optical rectification. Material dispersion as well as linear and nonlinear anisotropy is fully accounted for.

Signal readdressing by steering of spatial solitons in bulk nematic liquid crystals.

Fully three-dimensional spatial solitons in bulk nematic liquid crystals form self-consistent waveguides that are able to confine a weak, collinear copolarized signal at different wavelengths and with large trapping angles. We use a milliwatt cw source to generate a soliton and, by angular steering of the soliton, spatially readdress the guided signal.

Incoherent spatial solitary waves in nematic liquid crystals.

(2+1) -dimensional spatial solitary waves are generated by launching of milliwatt-power linearly polarized light beams in voltage-biased planar cells with undoped nematic liquid crystals, regardless of the degree of spatial coherence of the input. Coherent and incoherent self-trapping, as well as guidance of a weaker copolarized signal, is demonstrated.