Pulsed laser reshaping and fragmentation of upconversion nanoparticles — from hexagonal prisms to 1D nanorods through “Medusa”-like structures

One dimensional (1D) nanostructures attract considerable attention, enabling a broad application owing to their unique properties. However, the precise mechanism of 1D morphology attainment remains a matter of debate. In this study, ultrafast picosecond (ps) laser-induced treatment on upconversion nanoparticles (UCNPs) is offered as a tool for 1D-nanostructures formation. Fragmentation, reshaping through recrystallization process and bioadaptation of initially hydrophobic (β-Na_1.5Y_1.5F₆: Yb³⁺, Tm³⁺/β-Na_1.5Y_1.5F₆) core/shell nanoparticles by means of one-step laser treatment in water are demonstrated. “True” 1D nanostructures through “Medusa”-like structures can be obtained, maintaining anti-Stokes luminescence functionalities. A matter of the one-dimensional UCNPs based on direction of energy migration processes is debated. The proposed laser treatment approach is suitable for fast UCNP surface modification and nano-to-nano transformation, that open unique opportunities to expand UCNP applications in industry and biomedicine.

     

High resolution experimental measurement of turbulent flow field in a high pressure homogenizer model and its implications on turbulent drop fragmentation

Particle image velocimetry is performed on a model of a high pressure homogenizer, scaled for qualitative similarity of the one phase turbulent flow field in a production scale homogenizer. Flow fields in gap entrance, gap and gap outlet chamber are obtained with high resolution. The measurements show gap flow development and formation of a turbulent wall adherent jet when exiting into the outlet chamber. Turbulent kinetic energy spectra show how the turbulent energy available for fragmentation is transported over distance along the jet centre axis.The high resolution images are also used together with a Kolmogorov–Hinze theory framework for discussing drop fragmentation together with a direct evaluation of disruptive stresses from measurements. For the turbulent inertial mechanism large drops experience high fragmenting force close to eight gap heights downstream of the gap exit whereas this occurs closer to 20 gap heights for smaller drops. The turbulent viscous mechanism is most efficient at a downstream distance of eight gap heights into the outlet chamber for all drops sizes.     

Second allogeneic bone marrow transplantation in acute leukemia: a multicenter study from the Gruppo Italiano Trapianto Di Midollo Osseo (GITMO)

Thirty-eight second allogeneic bone marrow transplants (BMT) for acute leukemia relapsed after first BMT were performed in 13 Italian centers between 1987 and 1994. Twenty-one patients had acute myelogenous leukemia (AML), 17 acute lymphoblastic leukemia (ALL); at second BMT 24 patients were in complete remission (CR) and 14 in relapse. The median time to relapse after first BMT was 10 months (range 1-70). Grade II or greater acute graft-versus-host disease (GVHD) after second transplant occurred in 34.2% of patients and a chronic GVHD in 31.5% of patients. Twenty-four patients died: seven from early transplant-related mortality (TRM), 13 from relapse and four from late toxicity. As of 31 July 1996, at a median follow-up of 47 months (range 22-85), there are 14 survivors. The three-year probability of TRM, relapse and event-free survival (EFS) is 28%, 40% and 42% respectively. In 20 of 27 evaluable patients, remission duration after second BMT was longer than after the first BMT. A diagnosis of AML was correlated with a better outcome. These data support the usefulness of second allograft in selected patients with AML relapsing after a first BMT.     

Microprocessor Adaptive Control of Oil Temperature for Robot Arm Valves: A Practical Implementation

An assembly line quality control robotic arm has to have a very accurate regulation of the hydraulic oil temperature. An adaptive control strategy is designed and implemented, based on on-line parameter identification and optimum integral compensation realization. Design details, implementation, and performance data are presented.     

Determination of stoichiometric association constants by a non-iterative computational method

Computational methods for the estimation of stoichiometric association constants for multiple-ligand binding systems are currently based on non-linear least-squares regression analysis. These computational methods require sophisticated, iterative algorithms to assure convergence to a solution, as well as initial parameter and error estimates. A simple procedure, called lambda-invariance testing (LIT), was developed that provides a single-pass (non-iterative) estimation of stoichiometric association constants. The LIT method was applied to simulated binding data containing Gaussian error and to real data drawn from the literature. This method provided parameter estimates essentially equivalent to those obtained by least-squares regression analysis, with no initial parameter or error estimates required.     

Lyapunov exponents from time series: Variations for an algorithm

There are two basic procedures developed for the calculation of Lyapunov exponents. Although they seem to be almost opposite algorithms, it has been already shown that they can be considered as extreme cases of a single general method. the existing methods are revisited, a variation is presented, and a probabilistic approach is proposed. © 1995 John Wiley & Sons, Inc.     

Hierarchic plate and shell models based on p-extension

This paper is concerned with formulations of finite element models for beams, arches, plates and shells based on the principle of virtual work. The focus is on computer implementation of hierarchic sequences of finite element models suitable for numerical solution of a large variety of practical problems which may concurrently contain thin and thick plates and shells, stiffeners, and regions where three dimensional representation is required. The approximate solutions corresponding to the hierarchic sequence of models converge to the exact solution of the fully three dimensional model. The stopping criterion is based on (1) estimation of the relative error in energy norm; (2) equilibrium tests and (3) observation of the convergence of quantities of interest.