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LaNiO3(LNO) thin films are widely used as electrode materials. Yet, their properties greatly depend on such parameters as strain state and defect density. In this work, we present a detailed structural characterization of epitaxial LNO thin films grown on LaAlO3(001). A noticeable lack of contrast between La/Ni ions occurs in selected areas as seen by scanning transmission electron microscope, high-angle annular dark-field imaging (STEM-HAADF). By using atomistic modelization and image simulations, we show that this effect, rather than signaling cation interfusion or other spurious effects, results from different Ruddlesden-Popper faulted combinations with 1/2a⟨111⟩ relative displacement of defect free perovskite blocks, in the LaNiO3perovskite

We report on the structural characterization of epitaxial InSb films grown on InP substrates by atomic layer molecular beam epitaxy at relatively low temperatures (330 ○C < T < 400 ○C). Moreover, we study the effect of the introduction of an intermediate InSb/InP buffer layer grown by molecular beam epitaxy. The studies were carried out by TEM and HRTEM, to investigate the densities and nature of the defects and the accommodation mechanism between the two types of layers which have a large lattice mismatch (10.4%). Results show a high defect density at the interface vicinity whatever the growth method employed, with or without buffer layers, but better quality layers are obtained as growth proceeds. The prevailing type of defects are threading dislocations and stacking faults for both types of samples, but the introduction of the intermediate layers leads to the formation of two types of complex three-dimensional defects, consisting in crystal misorientations, that induce an anomalous growth of the InSb layer leading to different growth rates and the formation of pyramidal or truncated pyramidal hillocks on the surface. In this case scanning electron microscopy and Raman analysis were also performed to study the influence of the defects on surface morphology and confirm their structure. Moreover, anisotropy of the stacking fault distribution is noticed in this sample: the density for [ $\bar{110}$] –(111)A slip planes is higher than for the [110]–(111)B slip planes. Strain due to large lattice mismatch is relieved in both types of samples by the generation of a pure edge-type misfit dislocation array.

The effect of the dopant distribution on the oxygen diffusion in doped fluorites typically used for solid oxide fuel cells electrolyte applications has been analysed by using molecular dynamics simulations. The oxygen mass transport in both yttria‐stabilized zirconia (YSZ) and gadolinia‐doped ceria has been studied and compared in the range of temperatures between 1,159 and 1,959 K. A new methodology based on the analysis of local environments is used to describe the diffusion process at an atomic scale. Preferred vacancy migration pathways, most suitable conduction models, energy landscapes and jump efficiency have been detailed for each material. Finally, a particular case of non‐random distribution of dopants in YSZ is presented in order to quantitatively evaluate the effect of the dopant pattern on the mass transport properties and the potential of the methodology developed here for understanding and foreseeing real configurations at the nanoscale.

A mesoporous CaO‐loaded In2O3material (with Ca/In2O3ratios ranging from 2.5 to 8.5 at %) has been synthesized and used as resistive gas sensor for the detection of CO2. A nanostructured In2O3matrix has been obtained by hard template route from the SBA‐15 silica template. Additive presence does not distort the lattice of In2O3, which crystallizes in the Ia3 cubic space group. It has been proved by XRD, HRTEM, Raman and XPS measurements that samples contain not only CaO but also CaCO3in calcite phase as a consequence of CaO carbonation. Pure In2O3based sensors are low sensitive to CO2, whereas those containing the additive show an important response in the 300–5000 ppm range of gas concentrations. As seen by DRIFTS, the electrical response arises from the interaction between CO32–and CO2, yielding bicarbonates products. The reaction is water‐assisted, so that hydration of the sensing material ensures sensor reliability whilst its dehydration would inhibit sensor response. The use of CaCO3instead of CaO does not cause significant differences in electrical and DRIFTS data, which corroborates the important role played by carbonate species in the sensing mechanism.

SBA‐15 (2D hexagonal structure) and KIT‐6 (3D cubic structure) silica materials are used as templates for the synthesis of two different crystalline mesoporous WO3replicas usable as NO2gas sensors. High‐resolution transmission electron microscopy (HRTEM) studies reveal that single‐crystal hexagonal rings set up the atomic morphology of the WO3KIT‐6 replica, whereas the SBA‐15 replica is composed of randomly oriented nanoparticles. A model capable of explaining the KIT‐6 replica mesostructure is described. A small amount of chromium is added to the WO3matrix in order to enhance sensor response. It is demonstrated that chromium does not form clusters, but well‐distributed centers. Pure WO3KIT‐6 replica displays a higher response rate as well as a lower response time to NO2gas than the SBA‐15 replica. This behavior is explained by taking into account that the KIT‐6 replica has a higher surface area as demonstrated by Brunauer–Emmett–Teller analyses and its mesostructure is fully maintained after the screen‐printing step involved in sensors preparation. The presence of chromium in the material results in a shorter response time and improved sensor response to the lowest NO2concentrations tested. Electrical differences related to mesostructure are reduced as a result of additive introduction.

The differential diagnosis of sellar masses may be complex. Metastatic disease constitutes 1% of all pituitary lesions and sometimes mimics the clinical-radiological presentation of pituitary adenoma. The definitive diagnosis usually relies on histology, but occasionally even histological features of pituitary metastasis may resemble those of adenomas. We present a patient initially diagnosed with pituitary adenoma, but whose clinical course finally revealed pituitary metastasis of a hepatocellular carcinoma. The existing literature on this topic is reviewed.

Abstract: This work reports the transmission electron microscopy characterization of matched and mismatched InxAl1−xAs layers grown in a range of high temperatures (570-590C) on (100) InP substrates. We have observed two different coarse contrast modulations both oriented along the 〈010〉 directions. The appearance of such structures in cross-section and plan view orientations is described. We also show the evolution of these contrast modulations as approaching the substrate. The origin of one of these coarse patterns has been related to composition inhomogeneities driven by segregation and desorption phenomena at high temperature, and the other to composition modulations.

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Layers of In0.48Al0.52As grown by molecular beam epitaxy (MBE) on InP (100) substrates have been examined by transmission electron microscopy (TEM). At a low growth temperature (Tg=300°C) a {111} microtwinned structure was observed, the origin of which has been explained taking into account the limited kinetics of group III atoms and the differences in the propagation speed of the surface steps during MBE growth. For growth temperatures in the range 440–530°C, the defect densities decrease monotonically; threading dislocations and stacking faults on the {111} and {111} planes are the prevailing types of defect. The asymmetry of fault densities between the {111} and {111} planes has been discussed on the basis of the different mobilities of the partial dislocations bordering the faults.

The electrical, chemical and structural properties of the interfaces formed at room and low temperatures, between In and atomically clean In53Ga47As/InP(100) have been studied. Current-voltage measurements indicate that diodes formed at 80 K exhibit significantly higher Schottky barriers (φb= 0.45 eV) than diodes formed at 294 K (φb= 0.30 eV). The reactions occurring during the formation of InIn53Ga47As/InP(100) interfaces at room and low temperatures have been investigated using Soft X-Ray photoemission spectroscopy. Our results show that metallisation at room temperature results in a predominantly three dimensional mode of growth, accompanied by the out-diffusion of As. Low temperature (125 K) metallisation appears to reduce clustering and inhibit As out-diffusion. Examination of the resulting interfaces by transmission electron microscopy confirms the more uniform nature of the metal layers formed at low temperature. These observations, in conjunction with the barrier heights measured by the I-Vtechnique, are discussed in the context of currently supported models of Schottky barrier formation.

Optical anisotropy in mismatched InxGa1−xAs/InP and InyAl1−yAs/InP heterostructures has been investigated by variable azimuthal angle ellipsometry and reflectance difference spectroscopy. The two approaches are shown to yield strongly correlated results. A comparison to high resolution x-ray diffraction, transmission electron microscopy, and atomic force microscopy studies indicates that large optical anisotropies are associated with surface roughening that results from three-dimensional growth. Our findings demonstrate that fast and nondestructive measurements of optical anisotropy can provide important information about the growth mode and crystalline quality of strained epitaxial layers.

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Blue–green to near-IR switching electroluminescence (EL) has been achieved in a metal-oxide-semiconductor light emitting device, where the dielectric has been replaced by a Si-rich silicon oxide/nitride bilayer structure. To form Si nanostructures, the layers were implanted with Si ions at high energy, resulting in a Si excess of 19%, and subsequently annealed at 1000 °C. Transmission electron microscopy and EL studies allowed ascribing the blue–green emission to the Si nitride related defects and the near-IR band with the emission of the Si-nanoclusters embedded into the SiO_2 layer. Charge transport analysis is reported and allows for identifying the origin of this two-wavelength switching effect.

Systemic lupus erythematosus (SLE) is an uncommon etiology of pancreatic disease. Up to now, only 3 cases of chronic pancreatitis associated with SLE have been reported in adults. We report the case of a 14-year-old girl with SLE and calcifying chronic pancreatitis. At the age of 4 she was diagnosed with SLE. She presented with several acute exacerbations of SLE that were managed with prednisone and azathioprine. At the age of 9, she was admitted with abdominal pain and elevation of serum amylase and lipase levels; no gallstones were found on ultrasound, and treatment with azathioprine was withdrawn. Thereafter, she developed numerous episodes of acute pancreatitis. Later, an ERCP showed pancreatic calcifications and distortion of the main pancreatic duct, both findings consistent with established chronic pancreatitis. At the age of 14, her condition worsened progressively, and a surgical procedure (corporo-caudal spleno-pancreatectomy) was performed. The pathology specimen showed acinar atrophy and intense fibrosis. After surgery, the patient has remained pain-free and is enjoying a normal life.

Purpose:Spiegelian hernias (SH) represent only 2% of abdominal hernias. Treating ten outpatient cases motivated both the presentation of our experiences and a review of diagnostic and surgical treatment procedures. Predisposing factors, clinical presentation, diagnostic methods, surgical procedure, time spent in the Unit and the postoperative course have been analysed. Results:a predisposing factor was observed in eight patients. In four cases patients suffered abdominal pain, non-specific discomfort occurred in three and in six a mass was observed. Ecography in four patients and a computerised scan (CT) in two cases confirmed the diagnosis. Herniorrhaphy was performed in two patients, hernioplasty with a mesh in seven cases and a double polypropylene mesh was used once. There was no morbidity and the average length of time in the Unit was 99.3 min. To date no recurrences have been reported. Conclusion:SH is associated with several predisposing factors. Diagnosis can be difficult due to location and non-specific symptoms. Clinical examination is essential for diagnosis, with complementary examinations such as an ecography and/or CT.

Transmission electron microscopy and optical absorption measurements on InxGa1-xAs tensile layers grown on InP (001), having a range of In composition varying between 42·0 and 51·6% and thicknesses of 0·1 and 0·4 µm, have been carried out. The characteristics of the growth mode depending on strain and layer thickness are presented, showing the degradation of the epilayer with increasing mismatch. In these tensile layers, a random three-dimensional mode of growth leading to a very rough surface morphology has been found in the most mismatched layers studied.MST/3330