Development of Bioglass/PEEK Composite Coating by Cold Gas Spray for Orthopedic Implants.

Cold gas spray (CGS) technology has allowed the development of biofunctional coatings composed of 45S5 and polyetheretherketone (PEEK). The combination of a bioactive glass material embedded in a polymeric matrix makes this composite an interesting material for orthopedic applications since this composite meets the biomechanical and biological requirements of an implant. In the present study, blends of bioactive glass 45S5 and PEEK powder with different granulometry and 45S5/PEEK ratio have been prepared. These mixtures of powders have been deposited onto PEEK substrates by CGS with the goal of incorporating a bioactive additive to the biocompatible polymer, which can improve the bone-implant interaction of PEEK. The deposition efficiency (DE) of the coatings has been evaluated, and from the results obtained, it was possible to conclude that DE is significantly affected by the granulometry and by the 45S5/PEEK ratio of the blends. By scanning electron microscopy (SEM) inspection, it was observed that the use of blends with high 45S5/PEEK ratio lead to the deposition of coatings with high content of 45S5. Finally, the friction behavior of the coatings was analyzed performing ball-on-disk tests and these experiments showed that the presence of glass particles has a beneficial role in the wear resistance.

Prognostic value of myocardial perfusion scintigraphy in diabetic patients and without coronary lesion. / Valor pronóstico de la gammagrafía de perfusión miocárdica en pacientes diabéticos sin lesiones coronarias.

OBJECTIVE: To determine the prognostic value of myocardial perfusion scintigraphy-gated SPECT in patients with diabetes mellitus and without obstructive coronary artery disease. MATERIALS AND METHODS: This retrospective study included consecutive patients undergoing adenosine stress-rest myocardial perfusion imaging (MPI) by 99mTc-tetrofosmin between 2009 and 2011. The patients had diabetes mellitus and coronary angiography without significant coronary lesions. In total, 37 diabetic patients (female/male: 20/17; mean age: 65.2 (range: 40-78). 29 non-diabetic patients were included wich are matched with the group of diabetic patients with positive MPI. The group of non-diabetic patients had scintigraphy with myocardial ischemia and without angiographic lesions. A 36-month clinical follow-up was performed, and major cardiac events were recorded. RESULTS: In 78.3% (29/37) of diabetic patients the scintigraphic study showed myocardial ischemia, while it was negative in the 21.7%. The cardiac event rate in both groups was 6%. In diabetics with a myocardial perfusion study with myocardial ischemia, there were 3 major cardiac events. In diabetic patients with negative study had no cardiac event. In the non-diabetic control group the cardiac events rate was 3.4% (1/29). CONCLUSION: In diabetic patients without obstructive coronary disease, myocardial perfusion study can be predictor of cardiac events. A negative study can be an indicator of a better cardiovascular prognosis.

Toward RGB LEDs based on rare earth-doped ZnO.

By using ZnO thin films doped with Ce, Tb or Eu, deposited via radiofrequency magnetron sputtering, we have developed monochromatic (blue, green and red, respectively) light emitting devices (LEDs). The rare earth ions introduced with doping rates lower than 2% exhibit narrow and intense emission peaks due to electronic transitions in relaxation processes induced after electrical excitation. This study proves zinc oxide to be a good host for these elements, its high conductivity and optical transparency in the visible range being as well exploited as top transparent electrode. After structural characterization of the different doped layers, a device structure with intense electroluminescence is presented, modeled, and electrically and optically characterized. The different emission spectra obtained are compared in a chromatic diagram, providing a reference for future works with similar devices. The results hereby presented demonstrate three operating monochromatic LEDs, as well as a combination of the three species into another one, with a simply-designed structure compatible with current Si technology and demonstrating an integrated red-green-blue emission.

Synchronization of Optomechanical Nanobeams by Mechanical Interaction.

The synchronization of coupled oscillators is a phenomenon found throughout nature. Mechanical oscillators are paradigmatic examples, but synchronizing their nanoscaled versions is challenging. We report synchronization of the mechanical dynamics of a pair of optomechanical crystal cavities that, in contrast to previous works performed in similar objects, are intercoupled with a mechanical link and support independent optical modes. In this regime they oscillate in antiphase, which is in agreement with the predictions of our numerical model that considers reactive coupling. We also show how to temporarily disable synchronization of the coupled system by actuating one of the cavities with a heating laser, so that both cavities oscillate independently. Our results can be upscaled to more than two cavities and pave the way towards realizing integrated networks of synchronized mechanical oscillators.

Memristive behaviour of Si-Al oxynitride thin films: the role of oxygen and nitrogen vacancies in the electroforming process.

The resistive switching properties of silicon-aluminium oxynitride (SiAlON) based devices have been studied. Electrical transport mechanisms in both resistance states were determined, exhibiting an ohmic behaviour at low resistance and a defect-related Poole-Frenkel mechanism at high resistance. Nevertheless, some features of the Al top-electrode are generated during the initial electroforming, suggesting some material modifications. An in-depth microscopic study at the nanoscale has been performed after the electroforming process, by acquiring scanning electron microscopy and transmission electron microscopy images. The direct observation of the devices confirmed features on the top electrode with bubble-like appearance, as well as some precipitates within the SiAlON. Chemical analysis by electron energy loss spectroscopy has demonstrated that there is an out-diffusion of oxygen and nitrogen ions from the SiAlON layer towards the electrode, thus forming silicon-rich paths within the dielectric layer and indicating vacancy change to be the main mechanism in the resistive switching.

Compact focusing grating couplers for silicon horizontal slot waveguides.

In this Letter, we present the design, simulation (2D and 3D), fabrication, and experimental characterization of compact and fully etched focusing gratings for a horizontal slot waveguide based on a silicon nitride layer sandwiched between amorphous silicon and a silicon-on-insulator. The measured coupling losses are about 4 dB with a 3 dB bandwidth of 38 nm. The fully etched configuration allows the fabrication in a single lithography step.

Aided phytostabilisation reduces metal toxicity, improves soil fertility and enhances microbial activity in Cu-rich mine tailings.

(Aided) phytostabilisation has been proposed as a suitable technique to decrease the environmental risks associated with metal(loid)-enriched mine tailings. Field scale evaluations are needed for demonstrating their effectiveness in the medium- to long-term. A field trial was implemented in spring 2011 in Cu-rich mine tailings in the NW of Spain. The tailings were amended with composted municipal solid wastes and planted with Salix spp., Populus nigra L. or Agrostis capillaris L. cv. Highland. Plant growth, nutritive status and metal accumulation, and soil physico- and bio-chemical properties, were monitored over three years (four years for plant growth). The total bacterial community, α- and ß-Proteobacteria, Actinobacteria and Streptomycetaceae were studied by DGGE of 16s rDNA fragments. Compost amendment improved soil properties such as pH, CEC and fertility, and decreased soil Cu availability, leading to the establishment of a healthy vegetation cover. Both compost-amendment and plant root activity stimulated soil enzyme activities and induced important shifts in the bacterial community structure over time. The woody plant, S. viminalis, and the grassy species, A. capillaris, showed the best results in terms of plant growth and biomass production. The beneficial effects of the phytostabilisation process were maintained at least three years after treatment.

Organosilane-functionalization of nanostructured indium tin oxide films.

Fabrication and organosilane-functionalization and characterization of nanostructured ITO electrodes are reported. Nanostructured ITO electrodes were obtained by electron beam evaporation, and a subsequent annealing treatment was selectively performed to modify their crystalline state. An increase in geometrical surface area in comparison with thin-film electrodes area was observed by atomic force microscopy, implying higher electroactive surface area for nanostructured ITO electrodes and thus higher detection levels. To investigate the increase in detectability, chemical organosilane-functionalization of nanostructured ITO electrodes was performed. The formation of 3-glycidoxypropyltrimethoxysilane (GOPTS) layers was detected by X-ray photoelectron spectroscopy. As an indirect method to confirm the presence of organosilane molecules on the ITO substrates, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were also carried out. Cyclic voltammograms of functionalized ITO electrodes presented lower reduction-oxidation peak currents compared with non-functionalized ITO electrodes. These results demonstrate the presence of the epoxysilane coating on the ITO surface. EIS showed that organosilane-functionalized electrodes present higher polarization resistance, acting as an electronic barrier for the electron transfer between the conductive solution and the ITO electrode. The results of these electrochemical measurements, together with the significant difference in the X-ray spectra between bare ITO and organosilane-functionalized ITO substrates, may point to a new exploitable oxide-based nanostructured material for biosensing applications. As a first step towards sensing, rapid functionalization of such substrates and their application to electrochemical analysis is tested in this work. Interestingly, oxide-based materials are highly integrable with the silicon chip technology, which would permit the easy adaptation of such sensors into lab-on-a-chip configurations, providing benefits such as reduced size and weight to facilitate on-chip integration, and leading to low-cost mass production of microanalysis systems.

Far-field characterization of the thermal dynamics in lasing microspheres.

This work reports the dynamical thermal behavior of lasing microspheres placed on a dielectric substrate while they are homogeneously heated-up by the top-pump laser used to excite the active medium. The lasing modes are collected in the far-field and their temporal spectral traces show characteristic lifetimes of about 2 ms. The latter values scale with the microsphere radius and are independent of the pump power in the studied range. Finite-Element Method simulations reproduce the experimental results, revealing that thermal dynamics is dominated by heat dissipated towards the substrate through the medium surrounding the contact point. The characteristic system scale regarding thermal transport is of few hundreds of nanometers, thus enabling an effective toy model for investigating heat conduction in non-continuum gaseous media and near-field radiative energy transfer.

Structural parameters effect on the electrical and electroluminescence properties of silicon nanocrystals/SiO2 superlattices.

The effect of the oxide barrier thickness (tSiO2) reduction and the Si excess ([Si]exc) increase on the electrical and electroluminescence (EL) properties of Si-rich oxynitride (SRON)/SiO2 superlattices (SLs) is investigated. The active layers of the metal-oxide-semiconductor devices were fabricated by alternated deposition of SRON and SiO2 layers on top of a Si substrate. The precipitation of the Si excess and thus formation of Si nanocrystals (NCs) within the SRON layers was achieved after an annealing treatment at 1150 °C. A structural characterization revealed a high crystalline quality of the SLs for all devices, and the evaluated NC crystalline size is in agreement with a good deposition and annealing control. We found a dramatic conductivity enhancement when the Si content is increased or the SiO2 barrier thickness is decreased, due to a larger interaction of the carrier wavefunctions from adjacent layers. EL recombination dynamics were studied, revealing radiative recombination decay times of the order of tens of microseconds. Lower lifetimes were found at higher [Si]exc, attributed to exciton confinement delocalization, whereas intermediate barrier thicknesses present the slowest decay. The electrical-to-light conversion efficiency increases monotonously at thicker barriers and smaller Si contents. We ascribe these effects mainly to free carriers, which enhance carrier transport through the SLs while strongly quenching light emission. Finally, the combination of the different results led us to conclude that tSiO2 âˆ¼ 2 nm and [Si]exc from 12 to 15 at% are the ideal structure parameters for a balanced electro-optical response of Si NC-based SLs.

Use of DMPC and DSPC lipids for verapamil and naproxen permeability studies by PAMPA.

Verapamil and naproxen Parallel Artificial Membrane Permeability Assay (PAMPA) permeability was studied using lipids not yet reported for this model in order to facilitate the quantification of drug permeability. These lipids are 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and an equimolar mixture of DMPC/DSPC, both in the absence and in the presence of 33.3 mol% of cholesterol. PAMPA drug permeability using the lipids mentioned above was compared with lecithin-PC. The results show that verapamil permeability depends on the kind of lipid used, in the order DMPC > DMPC/DSPC > DSPC. The permeability of the drugs was between 1.3 and 3.5-times larger than those obtained in lecithin-PC for all the concentrations of the drug used. Naproxen shows similar permeability than verapamil; however, the permeability increased with respect to lecithin-PC only when DMPC and DMPC/DSPC were used. This behavior could be explained by a difference between the drug net charge at pH 7.4. On the other hand, in the presence of cholesterol, verapamil permeability increases in all lipid systems; however, the relative verapamil permeability respect to lecithin-PC did not show any significant increase. This result is likely due to the promoting effect of cholesterol, which is not able to compensate for the large increase in verapamil permeability observed in lecithin-PC. With respect to naproxen, its permeability value and relative permeability respect lecithin-PC not always increased in the presence of cholesterol. This result is probably attributed to the negative charge of naproxen rather than its molecular weight. The lipid systems studied have an advantage in drug permeability quantification, which is mainly related to the charge of the molecule and not to its molecular weight or to cholesterol used as an absorption promoter.

Papel de la inflamación renal en la fisiopatología de la hipertensión sensible a sal / Role of renal inflammation in the physiopathology of salt-sensitive hypertension

La hipertensión sensible a sal es el aumento de la presión arterial luego de una sobrecarga salina, como consecuencia esencialmente de una disminución en la excreción renal de sodio. En los últimos años, ha sido desarrollada una teoría para explicar su origen que tiene como base la inflamación del tejido renal. El proceso inicia con la producción en los riñones de radicales libres derivados del metabolismo oxidativo. Luego se desarrolla un mecanismo de inflamación del intersticio renal por infiltración de linfocitos T, y otras células inmunológicas. Fundamentalmente los linfocitos T incrementan la producción de angiotensina II que estimula la retención de sodio y agua a este nivel, favoreciendo el desarrollo de hipertensión sensible a sal. La relación entre infiltración renal por células del sistema inmune e hipertensión sensible a sal permite, en parte, explicar la asociación entre enfermedades autoinmunes y la hipertensión arterial. El uso de antioxidantes y el diseño de nuevos fármacos pueden ser una alternativa adicional al tratamiento de los pacientes afectados.

Salt-sensitive hypertension is produced by a decrease in salt renal excretion after a salt overload. Over the last few years, a new theory has been developed to explain this condition based on renal tissue inflammation. This process begins with free radicals production in renal tissue due to oxidative metabolism. Then they favor a renal inflammation mechanism with T-lymphocytes infiltration and other immune cells. Essentially, T-lymphocytes determine an increase in angiotensin II production which raises sodium and water retention. Association among autoimmune diseases and hypertension may be explained, in part, by the relationship between salt-sensitive hypertension and renal inflammation. The use of antioxidant drugs and the development of new medicaments may be a choice for treating patients affected with this condition.

Er-doped light emitting slot waveguides monolithically integrated in a silicon photonic chip.

An integrated erbium-based light emitting diode has been realized in a waveguide configuration allowing 1.54 µm light signal routing in silicon photonic circuits. This injection device is based on an asymmetric horizontal slot waveguide where the active slot material is Er(3+) in SiO2 or Er(3+) in Si-rich oxide. The active horizontal slot waveguide allows optical confinement, guiding and lateral extraction of the light for on-chip distribution. Light is then coupled through a taper section to a passive Si waveguide terminated by a grating which extracts (or inserts) the light signal for measuring purposes. We measured an optical power density in the range of tens of µW/cm(2) which follows a super-linear dependence on injected current density. When the device is biased at high current density, upon a voltage pulse (pump signal), free-carrier and space charge absorption losses become large, attenuating a probe signal by more than 60 dB/cm and thus behaving conceptually as an electro-optical modulator. The integrated device reported here is the first example, still to be optimized, of a fundamental block to realize an integrated silicon photonic circuit with monolithic integration of the light emitter.

[Hemodynamic effects of intravenous omeprazole in critically ill children]. / Efectos hemodinámicos del omeprazol por vía intravenosa en niños en estado crítico.

INTRODUCTION: Critical patients usually have hemodynamic disturbances which may become worse by the administration of some drugs. Omeprazole is a drug used in the prophylaxis of the gastrointestinal bleeding in these patients, but its cardiovascular effects are unknown. The objective was to study the hemodynamic changes produced by intravenous omeprazole in critically ill children and to find out if there are differences between two different doses of omeprazole. MATERIAL AND METHODS: A randomized prospective observational study was performed on 37 critically ill children aged from 1 month to 14 years of age who required prophylaxis for gastrointestinal bleeding. Of these, 19 received intravenous omeprazole 0.5mg/kg every 12 hours, and 18 received intravenous omeprazole 1mg/kg every 12 hours. Intravenous omeprazole was administered in 20 minutes by continuous infusion pump. Heart rate, systolic, diastolic and mean arterial blood pressure, central venous pressure and ECG were recorded at baseline, and at 15, 30, 60 and 120 minutes of the infusion. RESULTS: There were no significant changes in the electrocardiogram, heart rate, blood pressure and central venous pressure. No patients required inotropic therapy modification. There were no differences between the two doses of omeprazole. CONCLUSIONS: Intravenous omeprazole administration of 0.5mg/kg and 1mg/kg is a hemodynamically safe drug in critically ill children.

Histerectomía total laparoscópica asistida por robot: experiencia de Clínica Indisa / Robot-assisted total laparoscopic hysterectomy

Se comunica la experiencia y los resultados obtenidos de 110 casos de histerectomía total laparoscópica asistida por robot entre junio de 2010 y abril de 2013 en Clínica Indisa. Parámetros evaluados: diagnóstico, edad, índice de masa corporal (IMC), tiempo de instalación de trócares (TT), tiempo operatorio (TO), conversión a laparotomía, sangrado, dolor postoperatorio, estadía hospitalaria y complicaciones postoperatorias. Los diagnósticos preoperatorios más frecuentes fueron: miomatosis y adenomiosis. El promedio de edad fue de 45 años y de IMC 25,8 kg/m2, 7 por ciento de las pacientes con IMC mayor de 35. TT promedio de 14 min y TO fue de 81 min. No hubo conversión a laparotomía. Sangrado promedio de 17 ml. A las 48 horas pos intervención el 100 por ciento de las pacientes presentó un test de EVA de 0-2. Promedio de estadía hospitalaria fue 1,6 días. Hubo tres complicaciones postoperatorias: una neumonía, un desgarro vulvar y una dehiscencia de la cúpula vaginal. Conclusión: La histerectomía total laparoscópica asistida por robot es una técnica segura y ofrece ventajas al paciente y cirujano...

We reports the experience and results obtained after 110 total robot assisted laparoscopic hysterectomy from June 2010 to April 2013 at Indisa Clinic. Parameters evaluated: diagnostic, age, body mass index (BMI), trocars installation time (TT), intervention time (TO), conversion to laparotomy, bleeding, post operatory pain, hospital stay, and post operatory complications. The most frequent preoperatory diagnostic were uterine fibroid and adenomyosis. The age average was 45 years and BMI 25.8 Kg/m2 and 7 percent was over 35. TT average 14 min and TO 81 min. There were no conversions to laparotomy. Bleeding average was 17 ml. At 48 hours, 100 percent of patients had an EVA test of 0-2. The average of hospital stay was 1.6 days. Only three complications occurred: one pneumonia, one vulvar tear and one vaginal cuff dehiscence. Conclusion: robot assisted laparoscopy hysterectomy appears to be a safe surgical technique that offers benefits to the patient and also to the surgeon...

Electrical pump & probe and injected carrier losses quantification in Er doped Si slot waveguides.

Electrically driven Er(3+) doped Si slot waveguides emitting at 1530 nm are demonstrated. Two different Er(3+) doped active layers were fabricated in the slot region: a pure SiO(2) and a Si-rich oxide. Pulsed polarization driving of the waveguides was used to characterize the time response of the electroluminescence (EL) and of the signal probe transmission in 1 mm long waveguides. Injected carrier absorption losses modulate the EL signal and, since the carrier lifetime is much smaller than that of Er(3+) ions, a sharp EL peak was observed when the polarization was switched off. A time-resolved electrical pump & probe measurement in combination with lock-in amplifier techniques allowed to quantify the injected carrier absorption losses. We found an extinction ratio of 6 dB, passive propagation losses of about 4 dB/mm, and a spectral bandwidth > 25 nm at an effective d.c. power consumption of 120 µW. All these performances suggest the usage of these devices as electro-optical modulators.

Lipid profile and cardiovascular risk in anorexia nervosa; the effect of nutritional treatment.

OBJECTIVE: The aim of this study was to explore the lipid profile in patients with anorexia nervosa (AN), and the changes with refeeding. METHODS: The sample comprised 102 AN outpatients (mean age 22.32 ± 3.17). Blood tests, after 12-hour overnight fast, were performed before refeeding (M(0)) and after weight restoration (M(1)). Total cholesterol (TC), high-density lipoproteins (HDL), low-density lipoproteins (LDL) and triglycerides (TRG) were determined and the following cardiovascular risk markers were calculated: LDL/HDL and TC/HDL ratios. These cut-off points were considered: TC < 200 mg/dl; HDL > 40 mg/dl; LDL < 100 mg/dl and TRG < 150 mg/dl. RESULTS: The time leading to weight restoration was 8.16 ± 7.35 months. Considering patients with scores higher and lower than the corresponding cut-off points, X²-test revealed a significant difference (M(0)-M(1)) in case of TC (p < 0.05) as well as between LDL/HDL(0) and LDL/HDL(1) (p < 0.05) and between TC/HDL(0) and TC/HDL(1) (p < 0.01). Significant differences were found between HDL(0) and HDL(1) (p < 0.01) and between TRG(0) and TRG(1) (p < 0.01). Significant and negative associations between BMI(0) and TC(0) (r = -0.331; p < 0.05) and between TRG(0) and HDL(0) (r = -0.387; p < 0.05) were found. The association between TRG(1) and LDL(1) was significant and positive. DISCUSSION: Weight restoration tends to decrease the TC/HDL and LDL/HDL ratios despite a considerable percentage of patients maintain scores on the different variables of the lipid profile usually considered at risk.

Erbium emission in MOS light emitting devices: from energy transfer to direct impact excitation.

The electroluminescence (EL) at 1.54 µm of metal­oxide­semiconductor (MOS) devices withEr3C ions embedded in the silicon-rich silicon oxide (SRSO) layer has been investigated under different polarization conditions and compared with that of erbium doped SiO2 layers. EL time-resolved measurements allowed us to distinguish between two different excitation mechanisms responsible for the Er3C emission under an alternate pulsed voltage signal (APV). Energy transfer from silicon nanoclusters (Si-ncs) to Er3C is clearly observed at low-field APV excitation. We demonstrate that sequential electron and hole injection at the edges of the pulses creates excited states in Si-ncs which upon recombination transfer their energy to Er3C ions. On the contrary, direct impact excitation of Er3C by hot injected carriers starts at the Fowler­Nordheim injection threshold (above 5 MV cm(-1)) and dominates for high-field APV excitation.

Interactions between antiarrhythmic drugs and food.

OBJECTIVE: A drug interaction is defined as any alteration, pharmacokinetics and/or pharmacodynamics, produced by different substances, other drug treatments, dietary factors and habits such as drinking and smoking. These interactions can affect the antiarrhythmic drugs, altering their therapeutic efficacy and adverse effects. The aim of this study was to conduct a review of available data about interactions between antiarrhythmic drugs and food. METHODS: The purpose of this review was to report an update of the existing literature data on the main findings with respect to food and antiarrhythmic drugs interactions by means of a search conducted in PubMed, which yielded a total of 250 articles initially. RESULTS: After excluding different articles which were not focusing on the specific objective, the main results refer to interactions among antiarrhythmic drugs and food in general, grapefruit juice, and others like fibre or medicinal plants. DISCUSSION: Food may affect the bioavailability of antiarrhythmic drugs and in some specific cases (dairy products, rich-in-protein diets, grapefruit juice), this should be carefully considered. The best recommendation seems to advise patients to remove the grapefruit juice from their diet when treatment with these drugs. Fibre should be separated from taking these drugs and regarding medicinal plants and given their increased use, the anamnesis must include information about its use, the reason for that use and what types of plants are used, all in order to give the corresponding recommendations.