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In the design and engineering of functional core-shell nanostructures, material characterization at small length scales remains one of the major challenges. Here we show how electron tomography in high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) mode can be applied successfully to perform nano-metrological characterization of Au@Ag core-shell nanostructures. This work stresses the benefits of HAADF-STEM tomography and its use as a novel and rigorous tool for understanding the physical-chemical properties of complex 3D core-shell nanostructures. The reconstructed Au@Ag core-shell architecture was used as an input for discrete dipole approximation (DDA)-based electrodynamics simulations of the optical properties of the nanostructures. The implications of localized surface plasmon spectroscopy as well as Raman-enhanced spectroscopy are analysed.

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Pt impregnated on a Sn-beta catalyst results in a very promising catalyst for the selective hydrogenation of α,ß-unsaturated aldehydes, compared to the PtSn co-impregnated beta catalysts. Framework tin ions in the Sn-beta sample stabilize the nucleation of platinum nanoparticles inside the zeolite channel. These Pt(0)-Sn(4+) sites, which are only observed in the Pt/Sn-beta catalyst, have been shown to strongly activate the carbonyl group enhancing the hydrogenation rate of the C=O bond.

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Objetivos: Describir nuestra experiencia preliminar en el tratamiento de metástasis vertebrales mediante radiofrecuencia y cifoplastia combinadas en sesión única. Material y métodos: Se trataron cuatro pacientes con metástasis vertebral única confirmada histológicamente (mama, próstata, pulmón y mieloma en D12, L1, L5 y D12, respectivamente). La indicación en todos los casos fue el dolor con una mala respuesta al tratamiento médico habitual. Todos los pacientes presentaban dolor en el rango 6-7 de la escala visual analógica (EVA). En dos casos existía lesión lítica del muro posterior. Tras la obtención del consentimiento informado se realizó el procedimiento bajo sedación e infiltración anestésica local. Se efectuó abordaje transpedicular bilateral con sistemas de punción ósea 11G. Se insertaron de forma coaxial dos agujas de radiofrecuencia para efectuar un ciclo de ablación por cada pedículo. Durante el ciclo de ablación la punta del dispositivo correspondiente se situó en la unión del tercio medio con el tercio anterior del cuerpo vertebral, empleando la segunda aguja como sensor térmico, con su extremo a la altura del muro posterior. La duración de cada ciclo de ablación fue de 8 minutos, alcanzando temperaturas intratumorales de 70-80 ºC. A continuación se realizó cifoplastia transpedicular. Resultados: No se registraron complicaciones intra-periprocedimiento, con alta domiciliaria en las 24 horas siguientes. En todos los pacientes hubo una mejoría inmediata del dolor tras el procedimiento (con dolor de intensidad 1-2 de la EVA). En tres pacientes se retiró progresivamente la medicación analgésica, sin evidencia en ninguno de ellos de progresión local de la enfermedad ni recurrencia-aumento del dolor en el seguimiento (dolor de intensidad 1 de la EVA en un seguimiento en el rango de 8-14 meses). En un paciente no se pudo efectuar seguimiento clínico-radiológico posterior al alta. Conclusión: El empleo de radiofrecuencia asociada a cifoplastia en la enfermedad metastásica vertebral puede contribuir al manejo del dolor refractario al tratamiento médico y al control local de la enfermedad (AU)

Objectives: Describe our preliminary experience in the treatment of vertebral metastases by radiofrequency and Kyphoplasty combined in one single session. Material and methods: Four patients with histologically confirmed single spinal metastasis (breast, prostate, lung and myeloma in L1, L5, D12, D12, respectively) were treated. The indication in all cases was pain with a poor response to medical treatment. All patients had pain in the range 6-7 visual analogue scale (VAS). In two cases there was a lytic lesion of the spinal posterior wall. After obtaining informed consent, and under sedation and local anesthetic the procedure took place. The transpedicular approach took place with a 11 G bone puncture system. Two radiofrequency needles were coaxially inserted to carry out an ablation cycle through each pedicle. During the ablation cycle the tip of the ablation neddle stood between the anterior and middle third of the vertebral body, while the second needle was used as thermal sensor with its end to the height of the vertebral posterior wall. The duration of each cycle of ablation was 8 minutes reaching intratumoral temperatures of 70-80 °C. Transpedicular Kyphoplasty was performed subsequently. Results: No complications were reported during or after the procedure and patients were discharged in the first 24 hours. There was an immediate improvement in pain after the procedure (with a VAS 1-2 intensity pain) in all patients. During follow up, analgesic medication was withdrawn in three patients, and there was no evidence of disease progression or recurrence of pain (pain intensity 1 (VAS) in a follow-up in the range of 8-14 months). Clinical and radiological follow-up after discharge could not be performed on a patient. Conclusion: The use of radio-frequency associated with Kyphoplasty in vertebral metastatic disease can contribute to the management of refractory pain to medical treatment (AU)

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There is a critical need for improved methane-oxidation catalysts to both reduce emissions of methane, a greenhouse gas, and improve the performance of gas turbines. However, materials that are currently available either have low activity below 400°C or are unstable at higher temperatures. Here, we describe a supramolecular approach in which single units composed of a palladium (Pd) core and a ceria (CeO(2)) shell are preorganized in solution and then homogeneously deposited onto a modified hydrophobic alumina. Electron microscopy and other structural methods revealed that the Pd cores remained isolated even after heating the catalyst to 850°C. Enhanced metal-support interactions led to exceptionally high methane oxidation, with complete conversion below 400°C and outstanding thermal stability under demanding conditions.

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Introducción: La premedicación anestésica está destinada a reducir la ansiedad y la respuesta al estrés que supone el período anterior a la intervención quirúrgica. El temor a lo desconocido, al dolor y la separación de los padres son elementos que se añaden a la ansiedad perioperatoria en la población pediátrica. La necesidad de encontrar una vía de administración idónea en niños que no añada más sufrimientos a los ya existentes, es un reto para los anestesiólogos. Objetivo: Los objetivos del presente estudio eran valorar la eficacia, el grado de sedación y el modo de aceptación de 2 modalidades de premedicación para niños: citrato de fentanilo oral transmucoso (CFOT) y midazolam oral disuelto en zumo de fruta. Material y método: Se estudiaron 2 grupos aleatorizados de 40 niños que iban a someterse a cirugía de diversas especialidades. Las dosis administradas fueron de 10 μg/kg de CFOT y 0,3 mg/kg de midazolam, administrados 30 minutos antes de la punción venosa. Las variables consideradas fueron: saturación de hemoglobina desde el inicio de la premedicación y en la sala de despertar, modo de aceptación, grado de sedación, actitud del niño al separarlo de los padres, ante la punción venosa y ante la inducción anestésica, retraso en el despertar, requerimiento de analgesia postoperatoria, aparición de efectos secundarios. Resultados: Los resultados se compararon utilizando la t de Student (p < 0,05), y se obtuvieron diferencias significativas en el grado de aceptación favorable al grupo de CFOT, así como la actitud del niño en la canalización venosa. No hubo diferencias en la separación de los padres y en la inducción anestésica. No se presentaron secundarismos significativos en ningún grupo, ni se apreció tampoco desaturación importante de hemoglobina tras la administración de la premedicación. Conclusiones: Creemos que el CFOT se nos plantea como una administración de premedicación segura, eficaz y cómoda para población pediátrica, que vaya a someterse a intervención quirúrgica, con un adecuado grado de sedación que facilita la separación de los padres, la canalización venosa y la inducción anestésica (AU)

Introduction: The aim of anaesthetic premedication is to reduce anxiety and stress prior to surgery. Paediatric patients suffer even more anxiety due to fear of the unknown and the separation from parents. The need to find out a suitable way of administering premedication to paediatric patients without causing any more trauma is a challenge for the anaesthesiologist. Objectives: The objective of the current study was to evaluate the efficacy, level of sedation and a way of accepting two different types of premedication for children: Oral Transmucosal Fentanyl Citrate (OTFC) and oral midazolam dissolved in fruit juice. Methods: In this study, 40 children who were going to be subjected to various types of surgery were randomised to receive OTFC 10 μg/kg and midazolam 0.3 mg/kg 30 minutes before venipuncture. Variables taken into account were: haemoglobin saturation from the beginning of premedication and inside the recovery room, way of accepting, level of sedation, child behaviour after separation from parents, venous puncture and anaesthetic induction, delay in wakening, need of post-surgical analgesia and appearance of secondary effects. Results: Results were compared using Student’s T (p < 0.05) and there were significant differences in favour of the OTFC group as far as the way of accepting a venous puncture was concerned. No differences in behaviour were observed after separation from parents and anaesthetic induction. There were no significant differences in haemoglobin saturation or secondary effects between both groups. Conclusions: We believe that the use of OTFC is safe, effective and a convenient way to premedicate a paediatric population, who will be undergoing a surgical procedure, with a reasonable degree of sedation which makes separation from their parents, venous catheterisation and anaesthetic induction easier (AU)

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We present an evaluation of electron tomography of buried InAs quantum dots using dark field 002 imaging conditions. The compositional sensitivity of this imaging condition gives strong contrast among III-V materials of differing compositions and, in principle, should allow an accurate 3D model of the buried structures to be produced. The large extinction distance allows specimens several hundred nanometres in thickness to be examined and reduces the effect of strain contrast in the images, with the advantage that it can be performed using conventional transmission electron microscopy techniques. A two-beam condition must be maintained for all images, and the presence of other strong diffraction effects at certain specimen orientation results reduces the number of orientations available for tomography by approximately 10%. The data presented here are limited due to a lack of angular range in the data set but we find that an acceptable 3D model of a buried quantum dot may be produced by imposing cylindrical symmetry on the data set.

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TiN-Ag nanocomposite was synthesized by dc arc-plasma method. Microstructures of TiN-Ag nanocomposite were carefully characterized by powder X-ray diffraction method and transmission electron microscopy, and nano-morphologies by three-dimensional electron tomography. It was found that the surface of nanocrystalline TiN matrix was densely covered by finely dispersed Ag nanoparticles, and it was found that they were physically attached but not chemically bonded from their orientation relationships.

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The time from the start of incubation to a positive reading of blood cultures (time-to-positivity; TTP) is related to the concentration of bacteria in blood. Information concerning the correlation of TTP with clinical parameters, and its usefulness as a prognostic factor in patients with Escherichia coli bacteraemia, is limited. To investigate the relationship of TTP to clinical parameters, 459 cases of monomicrobial E. coli bloodstream infections from a single institution between 1997 and 2005 were reviewed. All cases involved patients who were not undergoing antibiotic treatment at the time of blood sampling. The in-hospital mortality rate was 6.3%. Median TTP was significantly shorter for patients who died than for those who survived (9.7 h, inter-quartile range 7.85-11.05 h vs. 11.2 h, inter-quartile range 10.1-11.4 h; p <0.001). Patients with TTP in the lowest quartile were more likely to be female, to have a non-urinary tract or an unknown origin of bacteraemia, to have severe sepsis or shock, and to subsequently die. In a multivariable Cox regression model, the hazard ratio for death from any cause for patients with a short TTP was 3.13 (95% CI 1.28-7.64; p 0.01). TTP in patients with E. coli bacteraemia provides prognostic information beyond that provided by the presence of haematological illness, a Charlson score > or =3, a non-urinary tract origin of bacteraemia, and the presence of severe sepsis or shock.

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The aim of this study was to identify the risk factors for bacteremia in patients with limb cellulitis. Using the administrative and microbiology laboratory databases of a community teaching hospital, a review was conducted of all cases of community-acquired limb cellulitis that occurred during the period 1997-2004 and in which blood cultures had been performed. A comparison of demographical, clinical, and analytical data of patients with bacteremia versus patients without bacteremia was performed by univariate and multivariate analyses. Of 2,678 patients with cellulitis who presented to the hospital's emergency department, 308 were diagnosed with limb cellulitis and had blood cultures. Of these, 57 (18.5%) had bacteremia. In 24 of the 57 (42.1%) patients with bacteremia, the microorganism isolated in blood cultures was non-group-A beta-hemolytic Streptococcus, and in another 14 (24.6%), the microorganism identified was a gram-negative bacterium. Staphylococcus aureus was determined as the cause of bacteremia in just 6 (10.5%) patients and group A Streptococcus in 2 (3.5%). By logistic regression analysis, the following factors were associated with bacteremia: absence of previous antibiotic treatment (OR 5.3, 95% CI 1.4-20.3), presence of two or more comorbid factors simultaneously (OR 4.3, 95% CI 1.6-11.7), length of illness<2 days OR 2.44, 95% CI 1.07-5.56), and proximal limb involvement (OR 6, 95% CI 3.03-12.04). Patients with limb cellulitis who exhibit any of these characteristics are at increased risk of bacteremia. In such patients, it is imperative that blood cultures be performed.

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The equilibrium constants and enthalpic values of metal acyclovir complexes have been determined by calorimetry for Co(II) (log K=0.96+/-0.05, DeltaH (kJ/mol)=-19.7+/-1.3), Ni(II) (log K=1.39+/-0.03, DeltaH (kJ/mol)=-21.5+/-1.0), Cu(II) (log K=1.83+/-0.03, DeltaH (kJ/mol)=-23.2+/-0.8) and Zn(II) (log K=0.71+/-0.06, DeltaH (kJ/mol)=-18.6+/-1.5). The equilibrium constants are similar to those of the divalent ions with guanosine and 2,9-dimethylpurine. By comparison with previous thermodynamic data, it can be shown that the 2-hydroxyethoxymethyl group promotes coordination through N(7) versus N(1) of the guanine ring for 3d metal ions. These results reveal that the 2-hydroxyethoxymethyl group placed on the purine ring of guanine in acyclovir causes a greater effect than that of the 9-methyl in purines and similar to or greater than that of the ribose moiety in guanosine. The 2-hydroxyethyoxymethyl group of acyclovir mimics the role of ribose in deoxy-guanosine and guanosine promoting a similar coordination chemistry (with very close log K and DeltaH values) for acyclovir, deoxy-guanosine and guanosine with divalent metals.

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OBJECTIVE: To present a case of giant calculus of the bladder. METHODS/RESULTS: Herein we describe a case of a giant calculus of the bladder in a 72-year-old patient with almost twenty years' evolution without urological control and with symptoms of prostatic disease. Surgery disclosed a giant calculus of 12 x 9 cm weighing approximately 1 kg adhered to the bladder mucosa. CONCLUSIONS: Although the number of cases have dropped in our setting due to the technological advancements and availability of health services, giant calculus of the bladder is not an insignificant or rarely diagnosed condition.

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OBJECTIVE: To review the indications and complications of the use of endourological catheters in the treatment of urinary lithiasis and choice of catheter based on its physical and hydrodynamic characteristics and biocompatibility. METHODS: Data from our experimental and clinical studies, as well as those published in the literature are summarized. RESULTS: Polyurethane, C-flex and Percuflex catheters have the highest retaining capacity, while the silicone, Urosoft and Wiruthan catheters have the lowest. The tensile strength of polyurethane and copolymers is superior to that of silicone. The friction coefficient, which varies within the same material, influences the facility of catheter insertion. The number and size of the side vents are essential to catheter hydrodynamic behavior. Silicone is the most biocompatible material, followed by Urosoft. The polyurethanes and C-flex catheters cause important urothelial hyperplasia and edema of the lamina propia. CONCLUSIONS: The choice of endourological catheter should be individualized and based on the clinical indication. For prevention of obstruction from steinstrasse post-lithotripsy, a catheter with a high extraluminal flow and high retaining capacity is indicated to facilitate passage of stone fragments and to avoid catheter migration.

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We report a new case of silica urolithiasis in a 71-year-old patient with background of medicament ingesta (antacid) which could justify the formation of these calculi with so uncommon composition. Medicament calculi amounts about 1% from total urinary calculi. Among them, silica ones (silicon dioxide or Si O2) have been relate din their etiology to chronical ingest of antacid drugs, specially those with magnesium trisilicate. Silica formation in urine is facilitated and conditioned by an acid pH of it. Diagnosis and therapeutical approach does not change in relation to other lithiasis with similar dimension or location. After its composition report, and ruling out the possibility for patient's malingering, urine alkalinization was applied, with an excellent follow-up afterwards. The antacid was substituted by other drug. We analyze the most important aspects about this case. We also make reference to the main related bibliography.

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Presentamos un nuevo caso de litiasis urinaria de sílice en un paciente varón de 71 años con antecedentes de ingesta medicamentosa (antiácido) que pudiera justificar la formación de estos cálculos de composición poco común. Los cálculos medicamentosos constituyen aproximadamente un 1 por ciento del total de cálculos urinarios. Dentro de estos, los de sílice (dióxido de silicio o Si O2) han sido relacionados en cuanto a su etiología con la ingesta crónica de fármacos antiácidos, especialmente aquellos que contienen trisilicato de magnesio. La formación de sílice en orina estaría facilitada y condicionada a la presencia de valores ácidos en su pH. El diagnóstico de la litiasis y su enfoque terapéutico no varía con respecto a otros cálculos de similares dimensiones y localización. Tras el informe de su composición, y descartando simulación por parte del paciente, fue instaurada alcalinización urinaria, con una evolución posterior excelente. El antiácido fue sustituido por otro medicamento. Analizamos los aspectos más importantes acerca del caso. Hacemos referencia asimismo a la bibliografía más destacada (AU)

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OBJECTIVE: To analyze the clinical complications of double-J ureteral catheters. METHODS: The most relevant studies published in the literature since the self-retaining indwelling catheter was first described in 1967 are reviewed. RESULTS: The experience and results reported in the most relevant studies are presented. CONCLUSIONS: The double-J ureteral stent has become an integral part of the urological armamentarium. It allows good urinary drainage from the kidney to the bladder and is generally safe and well-tolerated. However, different complications may occur with short- or long-term use of indwelling stents. These complications vary from minor side effects such as hematuria, dysuria, frequency, flank and suprapubic pain, to major complications such as vesico-ureteric reflux, stent migration, encrustation, urinary infection, stent fracture, necrosis and ureteral fistula. Most of these complications require removal of the catheter.

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Stones with different compositions respond differently to shock wave lithofragmentation. Likewise, the various lithotrity systems used may have different effects on the stones. To determine the relationships between stone composition and their fragmentation patterns, we conducted an in vitro study using endoscopy, magnifying glass, light microscope and scanning electron microscope on fragments obtained after lithotrity of 60 pure stone with different compositions: calcium oxalate monohydrate and dihydrate (OXMH and OXDH), phosphocarbonate (PC), ammonium magnesium phosphate (AMF) and uric acid (UA). Fragmentation was carried out with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulse laser). No morphologic differences in the fractures induced by the various lithofragmenting sources were demonstrated. OXMH and UA stones basically break up by intercrystalline fracture and splitting of their concentric plates. OXDH breaks up mainly by intercrystalline fractures aided by the fibrillar organic material and phosphocarbonates found in the intercrystalline spaces. Fragmentation in infective stones (AMF and PC) occurs across the intercrystalline surfaces and by intracrystalline fracture. Ammonium urate fragments break up by intracrystalline fractures that run across the equatorial plane of its characteristic acicular microspheres.

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Case report of a patient bearer of a double-J ureteral catheter due to ureteral lithiasis. After persistent renoureteral pain and fever, the proximal migration of the catheter is confirmed radiologically. The predisposing factors for this complication, described in the literature, are reviewed.

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OBJECTIVE: To determine whether knowledge about the degree of radiopacity of the double-J ureteral catheters utilized in Spanish hospitals suffices for correct radiologic control and subsequent follow-up. METHODS: The CT attenuation index was utilized to determine the degree of radiopacity of 23 double-J ureteral stents, comprised of different biomaterials and from different manufacturers, that are used in Spanish hospitals. RESULTS: The values ranged from 1,000-3,070 Hounsfield units. CONCLUSION: All the catheters analyzed were sufficiently radiopaque to permit good radiologic control during insertion and subsequent follow-up. The radiopacity of the stent depends on the metal salt employed during the manufacturing process and not on the biomaterial.

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The results of shockwave lithofragmentation are conditioned by stone composition. Similarly, the different types of lithofragmenting energy can have different effects on the calculi. The purpose of this experimental study is to establish a relationship between calculi composition and type of energy used for fragmentation, with the results of the lithotriptsy treatment. 60 calculi, 12 for each pure composition selected (calcium oxalate mono and dihydrate, phosphocarbonate, ammonium magnesium phosphate and uric acid) underwent in vitro lithofragmentation with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulsed laser). It was carried out a study of fragmentation in particles under 3 mm and pulverization in particles under 0.5 mm, analyzing post-lithotriptsy fragments with scanning electron microscopy associated to X-ray dispersion energy. No relationship was shown between calculi composition and amount of energy supplied for the fragmentation. The lithiasic composition correlates to the fragmentation pattern, so that oxalocalcium calculi undergoes good fragmentation and poor pulverization, infective calculi have poor fragmentation but good pulverization and uric acid calculi show poor fragmentation and pulverization.

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