A multi-technique approach to understanding delithiation damage in LiCoO2 thin films.

We report on the delithiation of LiCoO2 thin films using oxalic acid (C2H2O4) with the goal of understanding the structural degradation of an insertion oxide associated with Li chemical extraction. Using a multi-technique approach that includes synchrotron radiation X-ray diffraction, scanning electron microscopy, micro Raman spectroscopy, photoelectron spectroscopy and conductive atomic force microscopy we reveal the balance between selective Li extraction and structural damage. We identify three different delithiation regimes, related to surface processes, bulk delithiation and damage generation. We find that only a fraction of the grains is affected by the delithiation process, which may create local inhomogeneities. However, the bulk delithiation regime is effective to delithiate the LCO film. All experimental evidence collected indicates that the delithiation process in this regime mimics the behavior of LCO upon electrochemical delithiation. We discard the formation of Co oxalate during the chemical extraction process. In conclusion, the chemical route to Li extraction provides additional opportunities to investigate delithiation while avoiding the complications associated with electrolyte breakdown and simplifying in-situ measurements.

Mapping stress in polycrystals with sub-10 nm spatial resolution.

From aircraft to electronic devices, and even in Formula One cars, stress is the main cause of degraded material performance and mechanical failure in applications incorporating thin films and coatings. Over the last two decades, the scientific community has searched for the mechanisms responsible for stress generation in films, with no consensus in sight. The main difficulty is that most current models of stress generation, while atomistic in nature, are based on macroscopic measurements. Here, we demonstrate a novel method for mapping the stress at the surface of polycrystals with sub-10 nm spatial resolution. This method consists of transforming elastic modulus maps measured by atomic force microscopy techniques into stress maps via the local stress-stiffening effect. The validity of this approach is supported by finite element modeling simulations. Our study reveals a strongly heterogeneous distribution of intrinsic stress in polycrystalline Au films, with gradients as high as 100 MPa nm-1 near the grain boundaries. Consequently, our study discloses the limited capacity of macroscopic stress assessments and standard tests to discriminate among models, and the great potential of nanometer-scale stress mapping.

Validation of an HPLC-DAD/UV method for the quantification of cyclamate in tabletop sweeteners: risk of exceeding the acceptable daily intake.

Cyclamate is widely used as intense sweetener in the European Union. The absence of a maximum limit for the use of cyclamate in tabletop sweeteners and the growing demand for this type of product highlights the importance of developing robust analytical methods for the determination of its content to understand if the consumption of tabletop sweeteners can have a negative impact on human health. The present work aimed at the optimisation and validation of an high-performance liquid chromatography (HPLC) analytical method for cyclamate determination in tabletop sweeteners based on the procedure of European Standard EN 12857. The validated method was then applied to the determination of this sweetener in different types of tabletop sweeteners (liquid, powder and tablets). Both standards and samples solutions were submitted to a derivatisation procedure which converted cyclamate to N,N-dichlorocyclohexylamine. The derivatised product was separated and quantified using a reversed-phase column, a mobile phase composed of water (20%) and methanol (80%), isocratic flow of 1 ml min-1, and detection by ultraviolet spectrophotometry at a wavelength of 314 nm. The analytical method was internally validated according to the following validation parameters: working range, linearity, limits of detection and quantification, sensitivity, precision (repeatability and intermediate precision), and uncertainty. This method proved to be specific and selective for the determination of this sweetener, showing repeatability, RSDr ≤ 3%, intermediate precision, RSDR ≤ 3.3%, and recovery rates from 92% to 108% for the different tabletop sweeteners. The method uncertainty was 9.4%. The concentration of cyclamate in the samples varied significantly, from 2.9% to 73.9%, which demonstrated that a possible excessive consumption of one of the analysed sweeteners can lead to exceeding the acceptable daily intake for cyclamate.

Statistical analysis of teeth autotransplantation in Portugal's region of Chaves.

AIM: The aim of this study was to evaluate the success rate of 33 transplanted teeth in a northern population of Portugal. METHODS: The mean follow-up period was 7 years, ranging from 6 months to 20 years. RESULTS: Six teeth (18%) were rated as unsuccessful, 52% of the donor teeth were transplanted to receptor alveolus after immediate exodontia and 24% were transplanted to receptor alveolus surgically prepared. From the total number of cases, 64% had open root apex at the time of the transplantation and, in the latest control, of all teeth root development was over in 55%. Teeth ankylosis was present in 38% of all cases and 58% of all 33 transplants presented pulpar vitality. Data shows that, in males, teeth transplanted into natural alveolus were non-ankylosed, with normal color and vital teeth with incomplete root development at the time of the surgery. All cumulative curves obtained showed no statistical significance, mainly due to the low number of unsuccessful teeth autotransplantations. Orthodontic treatment performed after tooth autotransplantation showed success in 15% of all cases. CONCLUSION: Data reconfirms that autotransplantation of teeth is, in selected patients, the best option to replace a missing tooth in young patients.

Postcoalescence evolution of growth stress in polycrystalline films.

The growth stress generated once grains coalesce in Volmer-Weber-type thin films is investigated by time-multiscale simulations comprising complementary modules of (i) finite-element modeling to address the interactions between grains happening at atomic vibration time scales (~0.1 ps), (ii) dynamic scaling to account for the surface stress relaxation via morphology changes at surface diffusion time scales (~µs-ms), and (iii) the mesoscopic rate equation approach to simulate the bulk stress relaxation at deposition time scales (~sec-h). On the basis of addressing the main experimental evidence reported so far on the topic dealt with, the simulation results provide key findings concerning the interplay between anisotropic grain interactions at complementary space scales, deposition conditions (such as flux and mobility), and mechanisms of stress accommodation-relaxation, which underlies the origin, nature and spatial distribution, and the flux dependence of the postcoalescence growth stress.

Fenótipo Pena-Shokeir. Caso clínico / Pena-Shokeir phenotype. Case report

O fenótipo Pena-Shokeir (PSP) é caracterizado porartrogripose, hipoplasia pulmonar e anomalias faciais. Foirecentemente sugerido que seria secundário à redução dosmovimentos in utero devido a uma patologia intrínseca,independentemente da causa (Sequência de Deformação daAcinésia Fetal - FADS). Os autores descrevem um casoclássico de PSP com uma primeira ecografia obstétrica às 21semanas de gestação revelando diminuição dos movimentosfetais, micrognatia, mãos cerradas e pés botos. Aamniocentese revelou um cariótipo 46,XY normal. Às 23semanas, a ecografia obstétrica mostrou um feto imóvel,com restrição do crescimento intra-uterino e morfologiasobreponível, a que se associava hidrâmnios. O prognósticofoi explicado aos pais que decidiram interromper a gravidez.O estudo anátomo-patológico post mortem revelouhipertelorismo, orelhas de implantação baixa, micrognatia,pescoço curto e largo, discreto pterigia axilar e inguinal,flexão rígida das articulações dos cotovelos e anca,hiperextensão rígida dos joelhos, camptodactilia, pés botos,diminuição da massa muscular e hipoplasia pulmonar. Comoem muitos outros casos de PSP, a etiologia não foiesclarecida(AU)

Pena-Shokeir Phenotype (PSP) is characterized byarthrogryposis, facial anomalies and pulmonary hypoplasia.It has recently been suggested that it is secondaryto the reduction of movements in the uterus dueto an intrinsic pathology regardless of the cause (FetalAkinesia Deformation Sequence). Authors describe acase of a classic PSP, with a first obstetric ultrasound at 21 weeks of gestational age revealing reduction of fetalmovements, micrognathia, limb abnormalities withclubbed feet and clenched hands. Amniocentesis revealeda normal 46,XY karyotype. At 23 weeks, obstetricultrasound revealed intra-uterine growth restriction withabnormal fetal movements profile, identical fetal morphologyplus hypertelorism and new-onset polyhydramnios.Prognosis was explained to the parents who decidedto terminate pregnancy. Pathological study foundhypertelorism, low-set ears, micrognathia, short largeneck, small axillary and inguinal pterigia, rigid flexionat the elbows and hips with hyperextended knees, camptodactyly,clubbed feet, diminished muscle bulk andpulmonary hypoplasia. As in many other cases of PSP,etiology was not clarified(AU)

Reducing the surface roughness beyond the pulsed-laser-deposition limit.

Here, we outline the theoretical fundamentals of a promising growth kinetics of films from the vapor phase, in which pulsed fluxes are combined with temperature transients to enable short-range surface relaxations (e.g., species rearrangements) and to inhibit long-range relaxations (atomic exchange between species). A group of physical techniques (fully pulsed thermal and/or laser depositions) based on this kinetics is developed that can be used to prepare films with roughnesses even lower than those obtained with pulsed-laser deposition, which is the physical vapor-phase deposition technique that has produced the flattest films reported so far.

Preventing kinetic roughening in physical vapor-phase-deposited films.

The growth kinetics of the mostly used physical vapor-phase deposition techniques -molecular beam epitaxy, sputtering, flash evaporation, and pulsed laser deposition-is investigated by rate equations with the aim of testing their suitability for the preparation of ultraflat ultrathin films. The techniques are studied in regard to the roughness and morphology during early stages of growth. We demonstrate that pulsed laser deposition is the best technique for preparing the flattest films due to two key features [use of (i) a supersaturated pulsed flux of (ii) hyperthermal species] that promote a kinetically limited Ostwald ripening mechanism.

Síndrome de transfusão feto-fetal em gestação trigemelar. A propósito de um caso clínico / Twin-to-twin transfusion syndrome in a triplet pregnancy. A case report

Os autores relatam um caso clínico de uma gestação trigemelar, monocoriónica, triamniótica complicada por uma síndrome de transfusão feto-fetal (STFF). Tratava-se de uma primigesta de 30 anos de idade, à qual foi diagnosticado um STFF às 23 semanas de gestação. Foram realizadas amniocenteses descompressivas às 23 e 24 semanas. Às 25 semanas ocorre morte de um dos fetos, e na cesariana efectuada de imediato é constatada a morte de um segundo feto. O feto sobrevivente encontra-se bem. Esta situação clínica apresenta um prognóstico reservado, pelo que o diagnóstico de uma placentação mono ou bicoriónica, triamniótica, implica uma vigilância ecográfica seriada e frequente, de formaa detectar sinais precoces desta complicação

The authors report a case of a triplet pregnancy, monochorionic, triamniotic, complicated with a twin-totwin transfusion syndrome (TTTS). It was in a thirtyyears primipara, with a TTTS detected at the 23rd weekof gestation. Amnioreductions were performed at the23rd and 24th weeks. By the 25th week occurred the deathof one of the fetuses, and at the c-section performedimmediately, death of another foetus was observed. Thesurviving foetus is well. This clinical situation has a reserved prognosis, meaning that the diagnosis of a triplet pregnancy, mono or dichorionic, triamniotic, implies seried sonographic surveillance, for detecting earlier signs of this complication (AU)

Role of cluster transient mobility in pulsed laser deposition-type growth kinetics.

The ballistic motion of kinetically hyperthermal clusters on corrugated potential energy surfaces is studied by molecular dynamics simulations. Under pulsed laser deposition conditions, such clusters are generated due to the supersaturation flux and nonthermal energies of the incident species, a fraction of which is transferred to the clusters. This energy transfer, together with the flattening of the potential energy surface due to the cluster inner bonds, causes a lengthening of the ballistic paths as the cluster size increases. These results help explain the enhancement of growth kinetics by pulsed laser deposition.

Mathematical models applied to the Cr(III) and Cr(VI) breakthrough curves.

Trivalent and hexavalent chromium continuous biosorption was studied using residual brewer Saccharomyces cerevisiae immobilized in volcanic rock. The columns used in the process had a diameter of 4.5 cm and a length of 140 cm, working at an inlet flow rate of 15 mL/min. Breakthrough curves were used to study the yeast biosorption behavior in the process. The saturation time (ts) was 21 and 45 h for Cr(III) and Cr(VI), respectively, and a breakthrough time (tb) of 4 h for Cr(III) and 5 h for Cr(VI). The uptake capacity of the biosorbent for Cr(III) and Cr(VI) were 48 and 60 mg/g, respectively. Two non-diffusional mathematical models with parameters t0 and sigma were used to adjust the experimental data obtained. Microsoft Excel tools were used for the mathematical solution of the two parameters used.

Growth of single-crystalline KNbO3 nanostructures.

This communication reports on the growth of highly uniform KNbO3 nanowires exhibiting a narrow diameter distribution around 60 nm and a length-to-width ratio up to 100. The nanowires were prepared by a hydrothermal route, which enables simple, gram-scale production. A systematic study of the synthesized nanowires in terms of the morphological and chemical characteristics was carried out by varying the temperature-pressure conditions and the composition of the starting mixture. The results indicate that highly uniform single-crystalline nanowires form within a narrow window of the ternary phase diagram of KOH-Nb2O5-H2O.

Growth kinetics of one-dimensional KNbO3 nanostructures by hydrothermal processing routes.

The growth kinetics of one-dimensional single-crystalline KNbO(3) nanostructures (nanowires and nanofingers, the latter understood as defective nanowires) prepared by hydrothermal processing routes has been theoretically studied. A model taking into account the cube-based morphology of the nanostructures, their defects as the KOH proportion in the starting solution increases, and the partial depletion of species in the solution at the kink regions is proposed. Such a model allows the morphological evolution of the nanostructures to be successfully reproduced, shedding light on the origin of their highly anisotropic growth.

Gémeos siameses. Daignóstico ecográfico precoce: a propósito de um caso clínico / Gemelos siameses. Diagnóstico ecográfico precoz: a propósito de un caso / Conjoined twins. Fist trimester sonographic diagnosis: a case report

A existéncia de gémeos siameses é conhecida desde a antiguidade e pode ocorrer em aproximadamente 1 % das gestnóes monozigóticas ou em 1/200,000 nascimentos. No passado, o diagnóstico ecográfico apenas era possível no segundo ou mesmo no terceiro trimestres de gravidez. Actualmente, com o progresso da ecografia com imagens de cada vez melhor resolnáo e com a sua ampla utiliznáo na vigiláncia da gravidez, tornou-se possível o diagnóstico precoce. A ecografia realizada ás 12-13 semanas permite náo só o diagnóstico, mas também avaliar a extensáo de órgáos partilhados e as principais malformnóes associadas, estabelecendo o prognóstico. Assim, de acordo com a gravidade, a interruKáo médica da gravidez pode ser ponderada o mais precocemente possível, minimizando as consequéncias para a grávida e para o casal. Os autores apresentam um caso clínico em que o diagnóstico ecográfico de gémeos siameses craneo-toracópagos foi realizado ás 12 semanas. Posteriormente fazem um breve apanhado sobre a sua etiopatogenia, classifica0o, marcadores ecográficos de diagnóstico e conduta clínica (AU)

La existencia de gemelos siameses es conocida desde la antigüedad y puede ocurrir en aproximadamente el 10/o de las gestaciones monocigóticas o en 1/200.000 partos. En el pasado el diagnóstico ecográfico apenas era posible, incluso en el segundo y tercer trimestre del embarazo. Actualmente con el progreso de la ecografía con imágenes de cada vez mejor resolución y con su amplia utilización durante el embarazo se hizo posible el diagnóstico precoz. La ecografía realizada a la 12-13 semana permite no sólo su diagnóstico, sino también evaluar los órganos afectados y las principales malformaciones asociadas, estableciendo un pronóstico. Así, una interrupción médica del mismo puede ser programada lo más precozmente posible, minimizando las consecuencias para la embarazada. Los autores presentan un caso clínico en el que el diagnóstico ecográfico de gemelos siameses craneotoracópagos fue realizado a las 12 semanas del embarazo, y posteriormente hacen una breve reseña de su etiopatogenia, clasificación, marcadores ecográficos de diagnóstico y conducta clínica (AU)

The existence of conjoined twins has been described since ancient times. It has an incidence of approximately 10/o in monozygotic twins or 1/200,000 live births. In the past, the diagnosis was often first made by ultrasound examination in the second or third trimesters of pregnancy. With the advent of high-resolution obstetric ultrasound imaging and its growing use in pregnancy follow-up, an early diagnosis of this situation was made possible. The ultrasound scan made around the 12-13th week allows not only the diagnosis of this condition, but also has a prognostic value through identification of the extent of organ sharing and main associated malformations. Therefore, in accordance with the prognosis, pregnancy termination ought to be considered as early as possible, minimizing physical and psychological damage to the parents. The authors report a case of craniothoracopagus conjoined twins revealed by ultrasound at 12 weeks' gestation. Afterwards a summary of etiopathology, classification, ultrasound diagnostic criteria and management is made (AU)

Estenosis de la anastomosis uretero vesical en paciente con neovejiga ileal: tratamiento percutáneo con ureteroplastia y stent de nitinol / Percutaneous treatment with Nitinol stent implant in benign ureteral stenosis (patient with ileal neo-bladder)

Los autores realizan la presentación de un caso de estenosis ureteral distal benigna, en una paciente con cirugía por carcinoma de vejiga, con neovejiga ileal y reimplante ureteral bilateral. La misma fue tratada con éxito mediante la realización primero de una ureteroplastia con balón inflable, decidiéndose en el momento de la intervención, la colocación de un stent de Nitinol, debido a la imposibilidad de lograr una correcta y permanente dilatación del trayecto con la dilatación solamente. El resultado fue óptimo habiendo transcurrido hasta el momento 14 meses del procedimiento, no habiendo requerido otro tratamiento, permaneciendo con permeabilidad de la prótesis

Estenosis de la anastomosis uretero vesical en paciente con neovejiga ileal: tratamiento percutáneo con ureteroplastia y stent de nitinol / Percutaneous treatment with Nitinol stent implant in benign ureteral stenosis (patient with ileal neo-bladder)

Los autores realizan la presentación de un caso de estenosis ureteral distal benigna, en una paciente con cirugía por carcinoma de vejiga, con neovejiga ileal y reimplante ureteral bilateral. La misma fue tratada con éxito mediante la realización primero de una ureteroplastia con balón inflable, decidiéndose en el momento de la intervención, la colocación de un stent de Nitinol, debido a la imposibilidad de lograr una correcta y permanente dilatación del trayecto con la dilatación solamente. El resultado fue óptimo habiendo transcurrido hasta el momento 14 meses del procedimiento, no habiendo requerido otro tratamiento, permaneciendo con permeabilidad de la prótesis (AU)

Malformación adenomatoide quística: a propósito de dos casos clínicos / Cystic adenomatoid malformation: about two cases

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Hallazgos con ecografía Doppler color y tomografía computada helicoidal en tumores renales: relación entre volumen y grado de neovascularización / Renal tumors: correlation of volume with neovascularity by means of color Doppler, US and helical CT

Entre julio de 1997 y agosto de 1998, se analizaron en nuestro Servicio 23 neoplasias renales de distinta histología que fueron estudiadas mediante ecografía convencional, Doppler color, Power Doppler y tomografía computada helicoidal, obteniéndose en todos los casos confirmación antomopatológica. Basándonos en sus características volumétricas, los tumores se clasificaron en tres grupos. A la vez, se utilizó Doppler color como power Doppler para caracterizar el tipo e intensidad de neuvascularización tumoral, para obtener distintos registros espectorales, arteriales y venosos, y para calcular las diferentes velocidades de flujo con sus índices de resistencia. Se realizó TC helicoidal, antes y después de la inyección de contraste yodado endovenoso, con el objeto de establecer una correlación entre el volumen ecográfico y el obtenido por tomografía, así como observar los diferentes tipos de realce vascular tumoral y entablar una relación con los hallazgos obtenidos mediante Doppler color y Power Doppler. Los hallazgos deberán ampliarse a un mayor número de casos pero los resultados iniciales indican una importante correlación entre el volumen tumoral y el grado de vascularización en el examen Doppler color, especialmente en tumores de pequeño volumen, con un predominio del patrón hipovascular de los mismos. También se observó un aporte importante de este último en la caracterización de los tumores renales en relación con su histopatología

Hallazgos con ecografía Doppler color y tomografía computada helicoidal en tumores renales: relación entre volumen y grado de neovascularización / Renal tumors: correlation of volume with neovascularity by means of color Doppler, US and helical CT

Entre julio de 1997 y agosto de 1998, se analizaron en nuestro Servicio 23 neoplasias renales de distinta histología que fueron estudiadas mediante ecografía convencional, Doppler color, Power Doppler y tomografía computada helicoidal, obteniéndose en todos los casos confirmación antomopatológica. Basándonos en sus características volumétricas, los tumores se clasificaron en tres grupos. A la vez, se utilizó Doppler color como power Doppler para caracterizar el tipo e intensidad de neuvascularización tumoral, para obtener distintos registros espectorales, arteriales y venosos, y para calcular las diferentes velocidades de flujo con sus índices de resistencia. Se realizó TC helicoidal, antes y después de la inyección de contraste yodado endovenoso, con el objeto de establecer una correlación entre el volumen ecográfico y el obtenido por tomografía, así como observar los diferentes tipos de realce vascular tumoral y entablar una relación con los hallazgos obtenidos mediante Doppler color y Power Doppler. Los hallazgos deberán ampliarse a un mayor número de casos pero los resultados iniciales indican una importante correlación entre el volumen tumoral y el grado de vascularización en el examen Doppler color, especialmente en tumores de pequeño volumen, con un predominio del patrón hipovascular de los mismos. También se observó un aporte importante de este último en la caracterización de los tumores renales en relación con su histopatología (AU)