Age-Independent Cartilage Generation for Synovium-Based Autologous Chondrocyte Implantation.

The articular cartilage layer of synovial joints is commonly lesioned by trauma or by a degenerative joint disease. Attempts to repair the damage frequently involve the performance of autologous chondrocyte implantation (ACI). Healthy cartilage must be first removed from the joint, and then, on a separate occasion, following the isolation of the chondrocytes and their expansion in vitro, implanted within the lesion. The disadvantages of this therapeutic approach include the destruction of healthy cartilage-which may predispose the joint to osteoarthritic degeneration-the necessarily restricted availability of healthy tissue, the limited proliferative capacity of the donor cells-which declines with age-and the need for two surgical interventions. We postulated that it should be possible to induce synovial stem cells, which are characterized by high, age-independent, proliferative and chondrogenic differentiation capacities, to lay down cartilage within the outer juxtasynovial space after the transcutaneous implantation of a carrier bearing BMP-2 in a slow-release system. The chondrocytes could be isolated on-site and immediately used for ACI. To test this hypothesis, Chinchilla rabbits were used as an experimental model. A collagenous patch bearing BMP-2 in a slow-delivery vehicle was sutured to the inner face of the synovial membrane. The neoformed tissue was excised 5, 8, 11 and 14 days postimplantation for histological and histomorphometric analyses. Neoformed tissue was observed within the outer juxtasynovial space already on the 5th postimplantation day. It contained connective and adipose tissues, and a central nugget of growing cartilage. Between days 5 and 14, the absolute volume of cartilage increased, attaining a value of 12 mm(3) at the latter juncture. Bone was deposited in measurable quantities from the 11th day onwards, but owing to resorption, the net volume did not exceed 1.5 mm(3) (14th day). The findings confirm our hypothesis. The quantity of neoformed cartilage that is deposited after only 1 week within the outer juxtasynovial space would yield sufficient cells for ACI. Since the BMP-2-bearing patches would be implanted transcutaneously in humans, only one surgical or arthroscopic intervention would be called for. Moreover, most importantly, sufficient numbers of cells could be generated in patients of all ages.

Incremental Value of the CRUSADE, ACUITY, and HAS-BLED Risk Scores for the Prediction of Hemorrhagic Events After Coronary Stent Implantation in Patients Undergoing Long or Short Duration of Dual Antiplatelet Therapy

BACKGROUND Multiple scores have been proposed to stratify bleeding risk, but their value to guide dual antiplatelet therapy duration has never been appraised. We compared the performance of the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines), ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy), and HAS-BLED (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly) scores in 1946 patients recruited in the Prolonging Dual Antiplatelet Treatment After Grading Stent-Induced Intimal Hyperplasia Study (PRODIGY) and assessed hemorrhagic and ischemic events in the 24- and 6-month dual antiplatelet therapy groups. METHODS AND RESULTS Bleeding score performance was assessed with a Cox regression model and C statistics. Discriminative and reclassification power was assessed with net reclassification improvement and integrated discrimination improvement. The C statistic was similar between the CRUSADE score (area under the curve 0.71) and ACUITY (area under the curve 0.68), and higher than HAS-BLED (area under the curve 0.63). CRUSADE, but not ACUITY, improved reclassification (net reclassification index 0.39, P=0.005) and discrimination (integrated discrimination improvement index 0.0083, P=0.021) of major bleeding compared with HAS-BLED. Major bleeding and transfusions were higher in the 24- versus 6-month dual antiplatelet therapy groups in patients with a CRUSADE score >40 (hazard ratio for bleeding 2.69, P=0.035; hazard ratio for transfusions 4.65, P=0.009) but not in those with CRUSADE score ≤40 (hazard ratio for bleeding 1.50, P=0.25; hazard ratio for transfusions 1.37, P=0.44), with positive interaction (Pint=0.05 and Pint=0.01, respectively). The number of patients with high CRUSADE scores needed to treat for harm for major bleeding and transfusion were 17 and 15, respectively, with 24-month rather than 6-month dual antiplatelet therapy; corresponding figures in the overall population were 67 and 71, respectively. CONCLUSIONS Our analysis suggests that the CRUSADE score predicts major bleeding similarly to ACUITY and better than HAS BLED in an all-comer population with percutaneous coronary intervention and potentially identifies patients at higher risk of hemorrhagic complications when treated with a long-term dual antiplatelet therapy regimen. CLINICAL TRIAL REGISTRATION URL: http://clinicaltrials.gov. Unique identifier: NCT00611286.

Post-Procedural Troponin Elevation and Clinical Outcomes Following Transcatheter Aortic Valve Implantation.

BACKGROUND Biomarkers of myocardial injury increase frequently during transcatheter aortic valve implantation (TAVI). The impact of postprocedural cardiac troponin (cTn) elevation on short-term outcomes remains controversial, and the association with long-term prognosis is unknown. METHODS AND RESULTS We evaluated 577 consecutive patients with severe aortic stenosis treated with TAVI between 2007 and 2012. Myocardial injury, defined according to the Valve Academic Research Consortium (VARC)-2 as post-TAVI cardiac troponin T (cTnT) >15× the upper limit of normal, occurred in 338 patients (58.1%). In multivariate analyses, myocardial injury was associated with higher risk of all-cause mortality at 30 days (adjusted hazard ratio [HR], 8.77; 95% CI, 2.07-37.12; P=0.003) and remained a significant predictor at 2 years (adjusted HR, 1.98; 95% CI, 1.36-2.88; P<0.001). Higher cTnT cutoffs did not add incremental predictive value compared with the VARC-2-defined cutoff. Whereas myocardial injury occurred more frequently in patients with versus without coronary artery disease (CAD), the relative impact of cTnT elevation on 2-year mortality did not differ between patients without CAD (adjusted HR, 2.59; 95% CI, 1.27-5.26; P=0.009) and those with CAD (adjusted HR, 1.71; 95% CI, 1.10-2.65; P=0.018; P for interaction=0.24). Mortality rates at 2 years were lowest in patients without CAD and no myocardial injury (11.6%) and highest in patients with complex CAD (SYNTAX score >22) and myocardial injury (41.1%). CONCLUSIONS VARC-2-defined cTnT elevation emerged as a strong, independent predictor of 30-day mortality and remained a modest, but significant, predictor throughout 2 years post-TAVI. The prognostic value of cTnT elevation was modified by the presence and complexity of underlying CAD with highest mortality risk observed in patients combining SYNTAX score >22 and evidence of myocardial injury.

Análisis de micromovilidad en vástagos femorales mediante ensayo dinámico de oscilaciones libres

La artroplastia de cadera se considera uno de los mayores avances quirúrgicos de la Medicina. La aplicación de esta técnica de Traumatología se ha incrementado notablemente en los últimos anos, a causa principalmente del progresivo incremento de la esperanza de vida. En efecto, con la edad aumentan los problemas de artrosis y osteoporosis, enfermedades típicas de las articulaciones y de los huesos que requieren en muchos casos la sustitución protésica total o parcial de la articulación. El buen comportamiento funcional de una prótesis depende en gran medida de la estabilidad primaria, es decir, el correcto anclaje de la prótesis en el momento de su implantación. Las prótesis no cementadas basan su éxito a largo plazo en la osteointegración que tiene lugar entre el material protésico y el tejido óseo, y para lograrla es imprescindible conseguir unas buenas condiciones de estabilidad primaria. El aflojamiento aséptico es la principal causa de fallo de artroplastia total de cadera. Este es un fenómeno en el que, debido a complejas interacciones de factores mecánicos y biológicos, se producen movimientos relativos que comprometen la funcionalidad del implante. La minimización de los correspondientes danos depende en gran medida de la detección precoz del aflojamiento. Para lograr la detección temprana del aflojamiento aséptico del vástago femoral se han ensayado diferentes técnicas, tanto in vivo como in vitro: análisis numéricos y técnicas experimentales basadas en sensores de movimientos provocados por cargas transmitidas natural o artificialmente, tales como impactos o vibraciones de distintas frecuencias. Los montajes y procedimientos aplicados son heterogéneos y, en muchas ocasiones, complejos y costosos, no existiendo acuerdo sobre una técnica simple y eficaz de aplicación general. Asimismo, en la normativa vigente que regula las condiciones que debe cumplir una prótesis previamente a su comercialización, no hay ningún apartado referido específicamente a la evaluación de la bondad del diseño del vástago femoral con respecto a la estabilidad primaria. El objetivo de esta tesis es desarrollar una metodología para el análisis, in vitro, de la estabilidad de un vástago femoral implantado, a fin de poder evaluar las técnicas de implantación y los diferentes diseños de prótesis previamente a su oferta en el mercado. Además se plantea como requisito fundamental que el método desarrollado sea sencillo, reversible, repetible, no destructivo, con control riguroso de parámetros (condiciones de contorno de cargas y desplazamientos) y con un sistema de registro e interpretación de resultados rápido, fiable y asequible. Como paso previo, se ha realizado un análisis cualitativo del problema de contacto en la interfaz hueso-vástago aplicando una técnica optomecánica del campo continuo (fotoelasticidad). Para ello se han fabricado tres modelos en 2D del conjunto hueso-vástago, simulando tres tipos de contactos en la interfaz: contacto sin adherencia y con holgura, contacto sin adherencia y sin holgura, y contacto con adherencia y homogéneo. Aplicando la misma carga a cada modelo, y empleando la técnica de congelación de tensiones, se han visualizado los correspondientes estados tensionales, siendo estos más severos en el modelo de unión sin adherencia, como cabía esperar. En todo caso, los resultados son ilustrativos de la complejidad del problema de contacto y confirman la conveniencia y necesidad de la vía experimental para el estudio del problema. Seguidamente se ha planteado un ensayo dinámico de oscilaciones libres con instrumentación de sensores resistivos tipo galga extensométrica. Las muestras de ensayo han sido huesos fémur en todas sus posibles variantes: modelos simplificados, hueso sintético normalizado y hueso de cadáver, seco y fresco. Se ha diseñado un sistema de empotramiento del extremo distal de la muestra (fémur) con control riguroso de las condiciones de anclaje. La oscilación libre de la muestra se ha obtenido mediante la liberación instantánea de una carga estética determinada y aplicada previamente, bien con una maquina de ensayo o bien por gravedad. Cada muestra se ha instrumentado con galgas extensométricas convencionales cuya señal se ha registrado con un equipo dinámico comercial. Se ha aplicado un procedimiento de tratamiento de señal para acotar, filtrar y presentar las respuestas de los sensores en el dominio del tiempo y de la frecuencia. La interpretación de resultados es de tipo comparativo: se aplica el ensayo a una muestra de fémur Intacto que se toma de referencia, y a continuación se repite el ensayo sobre la misma muestra con una prótesis implantada; la comparación de resultados permite establecer conclusiones inmediatas sobre los efectos de la implantación de la prótesis. La implantación ha sido realizada por un cirujano traumatólogo utilizando las mismas técnicas e instrumental empleadas en el quirófano durante la práctica clínica real, y se ha trabajado con tres vástagos femorales comerciales. Con los resultados en el dominio del tiempo y de la frecuencia de las distintas aplicaciones se han establecido conclusiones sobre los siguientes aspectos: Viabilidad de los distintos tipos de muestras sintéticas: modelos simplificados y fémur sintético normalizado. Repetibilidad, linealidad y reversibilidad del ensayo. Congruencia de resultados con los valores teóricos deducidos de la teoría de oscilaciones libres de barras. Efectos de la implantación de tallos femorales en la amplitud de las oscilaciones, amortiguamiento y frecuencias de oscilación. Detección de armónicos asociados a la micromovilidad. La metodología se ha demostrado apta para ser incorporada a la normativa de prótesis, es de aplicación universal y abre vías para el análisis de la detección y caracterización de la micromovilidad de una prótesis frente a las cargas de servicio. ABSTRACT Total hip arthroplasty is considered as one of the greatest surgical advances in medicine. The application of this technique on Traumatology has increased significantly in recent years, mainly due to the progressive increase in life expectancy. In fact, advanced age increases osteoarthritis and osteoporosis problems, which are typical diseases of joints and bones, and in many cases require full or partial prosthetic replacement on the joint. Right functional behavior of prosthesis is highly dependent on the primary stability; this means it depends on the correct anchoring of the prosthesis at the time of implantation. Uncemented prosthesis base their long-term success on the quality of osseointegration that takes place between the prosthetic material and bone tissue, and to achieve this good primary stability conditions is mandatory. Aseptic loosening is the main cause of failure in total hip arthroplasty. This is a phenomenon in which relative movements occur, due to complex interactions of mechanical and biological factors, and these micromovements put the implant functionality at risk. To minimize possible damage, it greatly depends on the early detection of loosening. For this purpose, various techniques have been tested both in vivo and in vitro: numerical analysis and experimental techniques based on sensors for movements caused by naturally or artificially transmitted loads, such as impacts or vibrations at different frequencies. The assemblies and methods applied are heterogeneous and, in many cases, they are complex and expensive, with no agreement on the use of a simple and effective technique for general purposes. Likewise, in current regulations for governing the conditions to be fulfilled by the prosthesis before going to market, there is no specific section related to the evaluation of the femoral stem design in relation to primary stability. The aim of this thesis is to develop a in vitro methodology for analyzing the stability of an implanted femoral stem, in order to assess the implantation techniques and the different prosthesis designs prior to its offer in the market. We also propose as a fundamental requirement that the developed testing method should be simple, reversible, repeatable, non-destructive, with close monitoring of parameters (boundary conditions of loads and displacements) and with the availability of a register system to record and interpret results in a fast, reliable and affordable manner. As a preliminary step, we have performed a qualitative analysis of the contact problems in the bone-stem interface, through the application of a continuous field optomechanical technique (photoelasticity). For this proposal three 2D models of bone–stem set, has been built simulating three interface contact types: loosened an unbounded contact, unbounded and fixed contact, and bounded homogeneous contact. By means of applying the same load to each model, and using the stress freezing technique, it has displayed the corresponding stress states, being more severe as expected, in the unbounded union model. In any case, the results clearly show the complexity of the interface contact problem, and they confirm the need for experimental studies about this problem. Afterward a free oscillation dynamic test has been done using resistive strain gauge sensors. Test samples have been femur bones in all possible variants: simplified models, standardized synthetic bone, and dry and cool cadaveric bones. An embedding system at the distal end of the sample with strong control of the anchoring conditions has been designed. The free oscillation of the sample has been obtained by the instantaneous release of a static load, which was previously determined and applied to the sample through a testing machine or using the gravity force. Each sample was equipped with conventional strain gauges whose signal is registered with a marketed dynamic equipment. Then, it has applied a signal processing procedure to delimit, filter and present the time and frequency response signals from the sensors. Results are interpreted by comparing different trials: the test is applied to an intact femur sample which is taken as a reference, and then this test is repeated over the same sample with an implanted prosthesis. From comparison between results, immediate conclusions about the effects of the implantation of the prosthesis can be obtained. It must be said that the implementation has been made by an expert orthopedic surgeon using the same techniques and instruments as those used in clinical surgery. He has worked with three commercial femoral stems. From the results obtained in the time and frequency domains for the different applications the following conclusions have been established: Feasibility of the different types of synthetic samples: simplified models and standardized synthetic femur. Repeatability, linearity and reversibility of the testing method. Consistency of results with theoretical values deduced from the bars free oscillations theory. Effects of introduction of femoral stems in the amplitude, damping and frequencies of oscillations Detection of micromobility associated harmonics. This methodology has been proved suitable to be included in the standardization process of arthroplasty prosthesis, it is universally applicable and it allows establishing new methods for the analysis, detection and characterization of prosthesis micromobility due to functional loads.

Magnetic resonance imaging based signal intensity mapping predicts appropriate therapies after prophylactic ventricular tachycardia substrate ablation in patients with previous myocardial infarction and secondary prevention implantable cardioverter-defibrillator implantation

The aim of this study was to determine the capability of ceMRI based signal intensity (SI) mapping to predict appropriate ICD therapies after PVTSA.

Double ion implantation and pulsed laser melting processes for third generation solar cells

In the framework of the third generation of photovoltaic devices, the intermediate band solar cell is one of the possible candidates to reach higher efficiencies with a lower processing cost. In this work, we introduce a novel processing method based on a double ion implantation and, subsequently, a pulsed laser melting (PLM) process to obtain thicker layers of Ti supersaturated Si. We perform ab initio theoretical calculations of Si impurified with Ti showing that Ti in Si is a good candidate to theoretically form an intermediate band material in the Ti supersaturated Si. From time-of-flight secondary ion mass spectroscopy measurements, we confirm that we have obtained a Ti implanted and PLM thicker layer of 135 nm. Transmission electron microscopy reveals a single crystalline structure whilst the electrical characterization confirms the transport properties of an intermediate band material/Si substrate junction. High subbandgap absorption has been measured, obtaining an approximate value of 104 cm−1 in the photons energy range from 1.1 to 0.6 eV.

Dual control of LIF expression and LIF receptor function regulate Stat3 activation at the onset of uterine receptivity and embryo implantation

Leukemia inhibitory factor (LIF) expression in the uterus is essential for embryo implantation in mice. Here we describe the spatial and temporal regulation of LIF signaling in vivo by using tissues isolated from uteri on different days over the implantation period. During this time, LIF receptors are expressed predominantly in the luminal epithelium (LE) of the uterus. Isolated epithelium responds to LIF by phosphorylation and nuclear translocation of signal transducer and activator of transcription (Stat) 3, but not by an increase in mitogen-activated protein kinase levels. The related cytokines Il-6, ciliary neurotrophic factor, as well as epidermal growth factor, do not activate Stat3, although epidermal growth factor stimulates mitogen-activated protein kinase. In vivo Stat3 activation is induced by LIF alone, resulting in the localization of Stat3 specifically to the nuclei of the LE coinciding with the onset of uterine receptivity. The responsiveness of the LE to LIF is regulated temporally, with Stat activation being restricted to day 4 of pregnancy despite the presence of constant levels of LIF receptor throughout the preimplantation period. Uterine receptivity is therefore under dual control and is regulated by both the onset of LIF expression in the endometrial glands and the release from inhibition of receptor function in the LE.

Leukemia inhibitory factor (LIF) and LIF receptor expression in human endometrium suggests a potential autocrine/paracrine function in regulating embryo implantation.

The uterine expression of leukemia inhibitory factor (LIF) is essential for embryo implantation in the mouse. Here, we describe the expression of LIF, related members of this group of cytokines, oncostatin M and ciliary neurotrophic factor, and the LIF receptor beta and glycoprotein gp130 in normal human tissues and in the endometrium of fertile women. Our results show that LIF is the only one of these factors expressed at detectable levels in the endometrium of women of proven fertility. LIF expression is restricted to the endometrial glands during the secretory/postovulatory phase but is not present in the endometrium during the proliferative/preovulatory phase. The LIF receptor beta is expressed during the proliferative and secretory phases of the cycle and is restricted to the luminal epithelium. The associated signal-transducing component of the LIF receptor, gp130, is also expressed in both the luminal and glandular epithelium throughout the cycle. These results suggest that uterine expression of LIF in humans, like mice, may have a role in regulating embryo implantation, possibly through an autocrine/paracrine interaction between LIF and its receptor at the luminal epithelium.

Immunolocalization of estrogen receptor protein in the mouse blastocyst during normal and delayed implantation.

We previously showed that estrogen receptor (ER) mRNA is present in preimplantation mouse embryos. The apparent synthesis of ER mRNA by the blastocyst at the time of implantation when estrogen is required was of special interest. A demonstration of the presence of ER protein would support the idea that estrogen can act directly on the embryo. The mouse embryo at the blastocyst stage is differentiated into two cell types, the trophectoderm and the inner cell mass. To determine whether ER mRNA is translated into ER protein and its cell-specific distribution, immunocytochemical analyses were performed in mouse blastocysts. ER protein was detected in all cell types of the normal, dormant, or activated blastocyst. To trace the fate of ER in these cell types, immunocytochemistry was performed in implanting blastocysts and early egg cylinder stage embryos developed in culture. Again, ER was detected in all cells of the implanting blastocyst. At the early egg cylinder stage, continued expression of ER was observed in cells derived from the inner cell mass or the trophoblast. In trophoblast giant cells, ER was concentrated in small regions of the nucleus, possibly the nucleoli, which was similar to that observed in dormant and activated blastocysts. The embryonic expression of ER at such early stages in a broad array of cells suggests that ER may have a general role during early development.

Electrical investigation of p-type 4H-SiC heavily doped by ion implantation

In the last decades, an increasing interest in the research field of wide bandgap semiconductors was observed, mostly due to the progressive approaching of silicon-based devices to their theoretical limits. 4H-SiC is an example among these, and is a mature compound for applications. The main advantages offered 4H-SiC in comparison with silicon are an higher breakdown field, an higher thermal conductivity, a higher operating temperature, very high hardness and melting point, biocompatibility, but also low switching losses in high frequencies applications and lower on-resistances in unipolar devices. Then, 4H-SiC power devices offer great performance improvement; moreover, they can work in hostile environments where silicon power devices cannot function. Ion implantation technology is a key process in the fabrication of almost all kinds of SiC devices, owing to the advantage of a spatially selective doping. This work is dedicated to the electrical investigation of several differently-processed 4H-SiC ion- implanted samples, mainly through Hall effect and space charge spectroscopy experiments. It was also developed the automatic control (Labview) of several experiments. In the work, the effectiveness of high temperature post-implant thermal treatments (up to 2000°C) were studied and compared considering: (i) different methods, (ii) different temperatures and (iii) different duration of the annealing process. Preliminary p + /n and Schottky junctions were also investigated as simple test devices. 1) Heavy doping by ion implantation of single off-axis 4H-SiC layers The electrical investigation is one of the most important characterization of ion-implanted samples, which must be submitted to mandatory post-implant thermal treatment in order to both (i) recover the lattice after ion bombardment, and (ii) address the implanted impurities into lattice sites so that they can effectively act as dopants. Electrical investigation can give fundamental information on the efficiency of the electrical impurity activation. To understand the results of the research it should be noted that: (a) To realize good ohmic contacts it is necessary to obtain spatially defined highly doped regions, which must have conductivity as low as possible. (b) It has been shown that the electrical activation efficiency and the electrical conductivity increase with the annealing temperature increasing. (c) To maximize the layer conductivity, temperatures around 1700°C are generally used and implantation density high till to 10 21 cm -3 . In this work, an original approach, different from (c), is explored by the using very high annealing temperature, around 2000°C, on samples of Al + -implant concentration of the order of 10 20 cm -3 . Several Al + -implanted 4H-SiC samples, resulting of p-type conductivity, were investigated, with a nominal density varying in the range of about 1-5∙10 20 cm -3 and subjected to two different high temperature thermal treatments. One annealing method uses a radiofrequency heated furnace till to 1950°C (Conventional Annealing, CA), the other exploits a microwave field, providing a fast heating rate up to 2000°C (Micro-Wave Annealing, MWA). In this contest, mainly ion implanted p-type samples were investigated, both off-axis and on-axis <0001> semi-insulating 4H-SiC. Concerning p-type off-axis samples, a high electrical activation of implanted Al (50-70%) and a compensation ratio below 10% were estimated. In the work, the main sample processing parameters have been varied, as the implant temperature, CA annealing duration, and heating/cooling rates, and the best values assessed. MWA method leads to higher hole density and lower mobility than CA in equivalent ion implanted layers, resulting in lower resistivity, probably related to the 50°C higher annealing temperature. An optimal duration of the CA treatment was estimated in about 12-13 minutes. A RT resistivity on the lowest reported in literature for this kind of samples, has been obtained. 2) Low resistivity data: variable range hopping Notwithstanding the heavy p-type doping levels, the carrier density remained less than the critical one required for a semiconductor to metal transition. However, the high carrier densities obtained was enough to trigger a low temperature impurity band (IB) conduction. In the heaviest doped samples, such a conduction mechanism persists till to RT, without significantly prejudice the mobility values. This feature can have an interesting technological fall, because it guarantee a nearly temperature- independent carrier density, it being not affected by freeze-out effects. The usual transport mechanism occurring in the IB conduction is the nearest neighbor hopping: such a regime is effectively consistent with the resistivity temperature behavior of the lowest doped samples. In the heavier doped samples, however, a trend of the resistivity data compatible with a variable range hopping (VRH) conduction has been pointed out, here highlighted for the first time in p-type 4H-SiC. Even more: in the heaviest doped samples, and in particular, in those annealed by MWA, the temperature dependence of the resistivity data is consistent with a reduced dimensionality (2D) of the VRH conduction. In these samples, TEM investigation pointed out faulted dislocation loops in the basal plane, whose average spacing along the c-axis is comparable with the optimal length of the hops in the VRH transport. This result suggested the assignment of such a peculiar behavior to a kind of spatial confinement into a plane of the carrier hops. 3) Test device the p + -n junction In the last part of the work, the electrical properties of 4H-SiC diodes were also studied. In this case, a heavy Al + ion implantation was realized on n-type epilayers, according to the technological process applied for final devices. Good rectification properties was shown from these preliminary devices in their current-voltage characteristics. Admittance spectroscopy and deep level transient spectroscopy measurements showed the presence of electrically active defects other than the dopants ones, induced in the active region of the diodes by ion implantation. A critical comparison with the literature of these defects was performed. Preliminary to such an investigation, it was assessed the experimental set up for the admittance spectroscopy and current-voltage investigation and the automatic control of these measurements.

Visual and optical performance and quality of life after implantation of posterior chamber phakic intraocular lens

Purpose To evaluate visual, optical, and quality of life (QoL) outcomes and intercorrelations after bilateral implantation of posterior chamber phakic intraocular lenses. Methods Twenty eyes with high to moderate myopia of 10 patients that underwent PRL implantation (Phakic Refractive Lens, Carl Zeiss Meditec AG) were examined. Refraction, visual acuity, photopic and low mesopic contrast sensitivity (CS) with and without glare, ocular aberrations, as well as QoL outcomes (National Eye Institute Refractive Error Quality of Life Instrument-42, NEI RQL-42) were evaluated at 12 months postoperatively. Results Significant improvement in uncorrected (UDVA) and best-corrected distance (CDVA) visual acuities were found postoperatively (p < 0.01), with significant reduction in spherical equivalent (p < 0.01). Low mesopic CS without glare was significantly better than measurements with glare for 1.5, 3, and 6 cycles/degree (p < 0.01). No significant correlations between higher order root mean square (RMS) with CDVA (r = −0.26, p = 0.27) and CS (r ≤ 0.45, p ≥ 0.05) were found. Postoperative binocular photopic CS for 12 cycles/degree and 18 cycles/degree correlated significantly with several RQL-42 scales. Glare index correlated significantly with CS measures and scotopic pupil size (r = −0.551, p = 0.04), but not with higher order RMS (r = −0.02, p = 0.94). Postoperative higher order RMS, postoperative primary coma and postoperative spherical aberration was significant higher for 5-mm pupil diameter (p < 0.01) compared with controls. Conclusions Correction of moderate to high myopia by means of PRL implantation had a positive impact on CS and QoL. The aberrometric increase induced by the surgery does not seem to limit CS and QoL. However, perception of glare is still a relevant disturbance in some cases possibly related to the limitation of the optical zone of the PRL.

Comparative Analysis of the Visual Performance After Cataract Surgery With Implantation of a Bifocal or Trifocal Diffractive IOL

PURPOSE: To evaluate and compare the visual, refractive, contrast sensitivity, and aberrometric outcomes with a diffractive bifocal and trifocal intraocular lens (IOL) of the same material and haptic design. METHODS: Sixty eyes of 30 patients undergoing bilateral cataract surgery were enrolled and randomly assigned to one of two groups: the bifocal group, including 30 eyes implanted with the bifocal diffractive IOL AT LISA 801 (Carl Zeiss Meditec, Jena, Germany), and the trifocal group, including eyes implanted with the trifocal diffractive IOL AT LISA tri 839 MP (Carl Zeiss Meditec). Analysis of visual and refractive outcomes, contrast sensitivity, ocular aberrations (OPD-Scan III; Nidek, Inc., Gagamori, Japan), and defocus curve were performed during a 3-month follow-up period. RESULTS: No statistically significant differences between groups were found in 3-month postoperative uncorrected and corrected distance visual acuity (P > .21). However, uncorrected, corrected, and distance-corrected near and intermediate visual acuities were significantly better in the trifocal group (P < .01). No significant differences between groups were found in postoperative spherical equivalent (P = .22). In the binocular defocus curve, the visual acuity was significantly better for defocus of -0.50 to -1.50 diopters in the trifocal group (P < .04) and -3.50 to -4.00 diopters in the bifocal group (P < .03). No statistically significant differences were found between groups in most of the postoperative corneal, internal, and ocular aberrations (P > .31), and in contrast sensitivity for most frequencies analyzed (P > .15). CONCLUSIONS: Trifocal diffractive IOLs provide significantly better intermediate vision over bifocal IOLs, with equivalent postoperative levels of visual and ocular optical quality.

Fitting of a New Design of Full Scleral Contact Lens in Advanced Keratoconus with Previous Implantation of Intracorneal Ring Segments

This case report reports the visual rehabilitation obtained with the fitting of a new design of full scleral contact lens (ICD 16.5 contact lens, Paragon Vision Sciences, distributed by Lenticon, Madrid, Spain) in a cornea with advanced keratoconus and previous implantation of intracorneal ring segment with a very limited effect. This eye had a refraction of –3.00 × 55° cylinder, providing a visual acuity of 0.5 LogMAR. The topographic pattern was very irregular with the presence of a significant central protrusion and a significant central corneal thinning. Some previous unsuccessful fittings have been performed with corneal and corneal-scleral lenses. A comfortable wearing was achieved with a fully scleral contact lens of 4600 μm of sagittal height, optical power of –11.25 D, and providing an apical clearance of 196 μm. A visual acuity of 0.0 LogMAR combined with a relevant aberrometric improvement was achieved with this contact lens. The patient was completely satisfied with the fitting. The result was maintained during 1 year after the fitting. Full scleral lenses are then able to provide comfortable wear and a significant increase in visual acuity combined with a significant improvement in the visual quality in eyes with advanced keratoconus.

Implantation of a diffractive trifocal intraocular lens: One-year follow-up

Purpose: To evaluate the visual, refractive, contrast-sensitivity, and aberrometric outcomes during a 1-year follow-up after implantation of a trifocal intraocular lens (IOL). Setting: Premium Clinic, Teplice, Czech Republic. Design: Prospective case series. Methods: This study included eyes of patients having cataract surgery with implantation of the trifocal IOL model AT Lisa tri 839MP. Distance, intermediate (66 and 80 cm), and near (33 and 40 cm) vision; contrast sensitivity; aberrometric outcomes; and the defocus curve were evaluated during a 12-month follow-up. The level of posterior capsule opacification (PCO) was also evaluated. Results: In 120 eyes (60 patients), 1 month postoperatively, an improvement was observed in all visual parameters (P ≤ .03) except corrected near and intermediate visual acuities (both P ≥ .05). From 1 month to 12 months postoperatively, small but statistically significant changes were observed in uncorrected and corrected distance and near visual acuities (all P ≤ .03) and in uncorrected intermediate visual acuity (P = .01). In the defocus curve, no significant differences were found between visual acuities corresponding to defocus levels of −1.0 diopter (D) and −2.0 D (P = .22). The level of ocular spherical aberration decreased statistically significantly at 6 months (P < .001). Ocular and internal higher-order aberrations increased minimally but significantly from 6 to 12 months postoperatively (P < .001). The mean 12-month PCO score was 0.32 ± 0.44 (SD). Four eyes (3.3%) required neodymium:YAG capsulotomy. Conclusion: The trifocal IOL provided complete and stable visual restoration after cataract surgery during a 12-month follow-up, with good levels of visual quality.

Management of subluxated cataract with capsule anchor implantation

We describe a small case series that provides preliminary evidence of the usefulness of a new capsule-anchoring device for the management of subluxated cataracts. Three eyes of 3 patients with traumatic subluxated cataract causing a significant visual loss were enrolled. Phacoemulsification was performed in all cases with implantation of a capsule-anchoring device (AssiAnchor) because partial zonular dehiscence was present. A significant visual improvement was achieved in the 3 cases. The capsular bag was well centered and the anchors firmly attached to the capsulorhexis and sclera at 12 months postoperatively. The capsule-anchoring device was helpful in managing traumatic subluxated cataracts, enabling effective centration of the intraocular lens–capsular bag complex and, consequently, effective visual restoration.