A computer-assisted microscopic analysis of bone tissue developed inside a polyactive plymer implanted into an equine articular surface

One of the most promising applications for the restoration of small or moderately sized focal articular lesions is mosaicplasty (MP). Although recurrent hemarthrosis is a rare complication after MP, recently, various strategies have been designed to find an effective filling material to prevent postoperative bleeding from the donor site. The porous biodegradable polymer Polyactive (PA; a polyethylene glycol terephthalate - polybutylene terephthalate copolymer) represents a promising solution in this respect. A histological evaluation of the longterm PA-filled donor sites obtained from 10 experimental horses was performed. In this study, attention was primarily focused on the bone tissue developed in the plug. A computer-assisted image analysis and quantitative polarized light microscopic measurements of decalcified, longitudinally sectioned, dimethylmethylene blue (DMMB)- and picrosirius red (PS) stained sections revealed that the coverage area of the bone trabecules in the PA-filled donor tunnels was substantially (25%) enlarged compared to the neighboring cancellous bone. For this quantification, identical ROIs (regions of interest) were used and compared. The birefringence retardation values were also measured with a polarized light microscope using monochromatic light. Identical retardation values could be recorded from the bone trabeculae developed in the PA and in the neighboring bone, which indicates that the collagen orientation pattern does not differ significantly among these bone trabecules. Based on our new data, we speculate that PA promotes bone formation, and some of the currently identified degradation products of PA may enhance osteo-conduction and osteoinduction inside the donor canal.

Estimating the benefit of a second bone anchored hearing implant in unilaterally implanted users with a testband.

Conclusion Using a second bone anchored hearing implant (BAHI) mounted on a testband in unilaterally implanted BAHI users to test its potential advantage pre-operatively under-estimates the advantage of two BAHIs placed on two implants. Objectives To investigate how well speech understanding with a second BAHI mounted on a testband approaches the benefit of bilaterally implanted BAHIs. Method Prospective study with 16 BAHI users. Eight were implanted unilaterally (group A) and eight were implanted bilaterally (group B). Aided speech understanding was measured. Speech was presented from the front and noise came either from the left, right, or from the front in two conditions for group A (with one BAHI, and with two BAHIs, where the second device was mounted on a testband) and in three conditions for group B (same two conditions as group A, and in addition with both BAHIs mounted on implants). Results Speech understanding in noise improved with the additional device for noise from the side of the first BAHI (+0.7 to +2.1 dB) and decreased for noise from the other side (-1.8 dB to -3.9 dB). Improvements were highest (+2.1 dB, p = 0.016) and disadvantages were smallest (-1.8 dB, p = 0.047) with both BAHIs mounted on implants. Testbands yielded smaller advantages and higher disadvantages of the additional BAHI (average difference = -0.9 dB).

Depth dependent lattice disorder and strain in Mn-implanted and post-annealed InAs thin films

The lattice order degree and the strain in as-grown, Mn-implanted and post-implantedannealedInAsthinfilms were investigated with depth resolution by means of Rutherford backscattering spectrometry in channeling conditions (RBS/C). Three main crystallographic axes were analyzed for both In and As sublattices. The behaviour of the induced defects was evaluated in two regions with different native defects: the interface and the surface. The results show that Mn implantation and post-implantation annealing are anisotropic processes, affecting in a different way the In and As sublattices. The mechanisms influencing the enhancement and deterioration of the crystal quality during the implantation are discussed in relation to the as-grown defects and the segregation of the elements

Preparation and characterization of stable aqueous suspensions of up-converting Er3+/Yb3+-doped LiNbO3 nanocrystals

The preparation of LiNbO3:Er3+/Yb3+ nanocrystals and their up-conversion properties have been studied. It is demonstrated that polyethyleneimine- (PEI) assisted dispersion procedures allow obtaining stable aqueous LiNbO3:Er3+/Yb3+ powder suspensions, with average size particles well below the micron range (100–200 nm) and the isoelectric point of the suspension reaching values well above pH 7. After excitation of Yb3+ ions at a wavelength of 980 nm, the suspensions exhibit efficient, and stable, IR-to-visible (green and red) up-conversion properties, easily observed by the naked eye, very similar to those of the starting crystalline bulk material.

Ion Beam Analysis of He-implanted fusion solid breedes

Introduction Lithium-based ceramics (silicates, titanates, ?) possess a series of advantages as alternative over liquid lithium and lithium-lead alloys for fusion breeders. They have a sufficient lithium atomic density (up to 540 kg*m-3), high temperature stability (up to 1300 K), and good chemical compatibility with structural materials. Nevertheless, few research is made on the diffusion behavior of He and H isotopes through polycrystalline structures of porous ceramics which is crucial in order to understand the mobility of gas coolants as well as, the release of tritium. Moreover, in the operating conditions of actual breeder blanket concepts, the extraction rate of the helium produced during lithium transmutation can be affected by the composition and the structure of the near surface region modifying the performance of BB materials

Thermal diffusion profile by NRA of Deuterium implanted in solid breeder blanket materials

This paper studies the relationship between aging, physical changes and the results of non-destructive testing of plywood. 176 pieces of plywood were tested to analyze their actual and estimated density using non-destructive methods (screw withdrawal force and ultrasound wave velocity) during a laboratory aging test. From the results of statistical analysis it can be concluded that there is a strong relationship between the non-destructive measurements carried out, and the decline in the physical properties of the panels due to aging. The authors propose several models to estimate board density. The best results are obtained with ultrasound. A reliable prediction of the degree of deterioration (aging) of board is presented. Breeder blanket materials have to produce tritium from lithium while fulfilling several strict conditions. In particular, when dealing with materials to be applied in fusion reactors, one of the key questions is the study of light ions retention, which can be produced by transmutation reactions and/or introduced by interaction with the plasma. In ceramic breeders the understanding of the hydrogen isotopes behaviour and specially the diffusion of tritium to the surface is crucial. Moreover the evolution of the microstructure during irradiation with energetic ions, neutrons and electrons is complex because of the interaction of a high number of processes.

Analysis and optimization of propagation losses in LiNbO3 optical waveguides produced by swift heavy-ion irradiation

The propagation losses (PL) of lithium niobate optical planar waveguides fabricated by swift heavy-ion irradiation (SHI), an alternative to conventional ion implantation, have been investigated and optimized. For waveguide fabrication, congruently melting LiNbO3 substrates were irradiated with F ions at 20 MeV or 30 MeV and fluences in the range 1013–1014 cm−2. The influence of the temperature and time of post-irradiation annealing treatments has been systematically studied. Optimum propagation losses lower than 0.5 dB/cm have been obtained for both TE and TM modes, after a two-stage annealing treatment at 350 and 375∘C. Possible loss mechanisms are discussed.

Ion beam analysis of as-received, H-implanted and post implanted annealed fusion steels

The elemental distribution for as-received (AR), H implanted (AI) and post-implanted annealed (A) Eurofer and ODS-Eurofer steels has been characterized by means of micro Particle Induced X-ray Emission (μ-PIXE), micro Elastic Recoil Detection (μ-ERD) and Secondary Ion Mass Spectrometry (SIMS). The temperature and time-induced H diffusion has been analyzed by Resonance Nuclear Reaction Analysis (RNRA), Thermal Desorption Spectroscopy (TDS), ERDA and SIMS techniques. μ-PIXE measurements point out the presence of inhomogeneities in the Y distribution for ODS-Eurofer samples. RNRA and SIMS experiments evidence that hydrogen easily outdiffuses in these steels even at room temperature. ERD data show that annealing at temperatures as low as 300 °C strongly accelerates the hydrogen diffusion process, driving out up to the 90% of the initial hydrogen.

D-depth profiling in as-implanted and annealed Li-based breeder blanket ceramics

In future power plants (i.e. DEMO), the nuclear fusion of hydrogen isotopes will be used for energy production. The behaviour of hydrogen isotopes in lithium-enriched ceramics for breeder blankets (BBs) is one of the most important items to be understood. In this paper we present the chemical, microstructural and morphological features of Li4SiO4, Li2TiO3 and a third ceramic candidate with a higher Li:Si proportion (3:1), implanted with D at an energy of 100 keV and at room temperature at a fluence of 1 × 1017 cm−2. The D depth-profile in as-implanted and annealed ceramics (at T ⩽ 200 °C) was characterised by Resonance Nuclear Reaction Analysis (RNRA). The RNRA data indicate that the total amount of D is retained at room temperature, while annealing at 100 °C promotes D release and annealing at T ⩾ 150 °C drives D to completely desorb from all the studied ceramics. D release will be discussed as a function of the microstructurural and morphological features of each material.

Experimental verification of intermediate band formation on titanium-implanted silicon

Intermediate band formation on silicon layers for solar cell applications was achieved by titanium implantation and laser annealing. A two-layer heterogeneous system, formed by the implanted layer and by the un-implanted substrate, was formed. In this work, we present for the first time electrical characterization results which show that recombination is suppressed when the Ti concentration is high enough to overcome the Mott limit, in agreement with the intermediate band theory. Clear differences have been observed between samples implanted with doses under or over the Mott limit. Samples implanted under the Mott limit have capacitance values much lower than the un-implanted ones as corresponds to a highly doped semiconductor Schottky junction. However, when the Mott limit is surpassed, the samples have much higher capacitance, revealing that the intermediate band is formed. The capacitance increasing is due to the big amount of charge trapped at the intermediate band, even at low temperatures. Ti deep levels have been measured by admittance spectroscopy. These deep levels are located at energies which vary from 0.20 to 0.28?eV below the conduction band for implantation doses in the range 1013-1014 at./cm2. For doses over the Mott limit, the implanted atoms become nonrecombinant. Capacitance voltage transient technique measurements prove that the fabricated devices consist of two-layers, in which the implanted layer and the substrate behave as an n+/n junction.

Electrical decoupling effect on intermediate band Ti-implanted silicon layers

We investigated the electrical transport properties of ultraheavily Ti-implanted silicon layers subsequently pulsed laser melted (PLM). After PLM, the samples exhibit anomalous electrical behaviour in sheet resistance and Hall mobility measurements, which is associated with the formation of an intermediate band (IB) in the implanted layer. An analytical model that assumes IB formation and a current limitation effect between the implanted layer and the substrate was developed to analyse this anomalous behaviour. This model also describes the behaviour of the function V/Delta V and the electrical function F that can be extracted from the electrical measurements in the bilayer. After chemical etching of the implanted layer, the anomalous electrical behaviour observed in sheet resistance and Hall mobility measurements vanishes, recovering the unimplanted Si behaviour, in agreement with the analytical model. The behaviour of V/Delta V and the electrical function F can also be successfully described in terms of the analytical model in the bilayer structure with the implanted layer entirely stripped.

Calculation of the spatial distribution of photovoltaic field by arbitrary 2D ilumination patterns en LiNbO3; application to photovoltaic particle trapping.

Patterns of evanescent photovoltaic field induced by illumination on a surface of lithium niobate (LN) have been calculated and compared with the experimental patterns of nano- and microparticles trapped by dielectrophoretic forces. A tool for this calculation has been developed. Calculo de distribución espacial de campo por efecto fotovoltaico con patrones arbitrarios de iluminación, en LiNbO3

Calculation of dielectrophoretic potential generated under illumination patterns on x- and z-cut LiNbO3 : application to photovoltaic particle trapping

The dielectrophoretic potential generated near the surface of a z-cut LiNbO3 by photovoltaic charge transport has been calculated for first time. The procedure and results are compared with the ones corresponding to x-cut. Diferences in the position, sharpness and time evolution are reported, and their implication on particle trapping are discussed.