835 resultados para Zr-Sm mixed oxides


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Combined prolactin (PRL) and growth hormone (GH) secretion by a single pituitary tumor can occur in approximately 5% of cases. However, in all previously reported patients, combined secretion of both hormones was present at the time of diagnosis. Here we describe a patient initially diagnosed with a pure prolactin-secreting microadenoma, who experienced the progressive apparition of symptomatic autonomous GH secretion while on intermittent long term dopamine agonist therapy. She was operated on, and immunohistochemical analysis of tumor tissue confirmed the diagnosis of pituitary adenoma with uniform co-staining of all cells for both GH and PRL. This patient represents the first documented occurrence of asynchronous development of combined GH and PRL secretion in a pituitary adenoma. Although pathogenic mechanisms implicated remain largely speculative, it emphasizes the need for long term hormonal follow up of patients harboring prolactinomas.

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In many research areas (such as public health, environmental contamination, and others) one deals with the necessity of using data to infer whether some proportion (%) of a population of interest is (or one wants it to be) below and/or over some threshold, through the computation of tolerance interval. The idea is, once a threshold is given, one computes the tolerance interval or limit (which might be one or two - sided bounded) and then to check if it satisfies the given threshold. Since in this work we deal with the computation of one - sided tolerance interval, for the two-sided case we recomend, for instance, Krishnamoorthy and Mathew [5]. Krishnamoorthy and Mathew [4] performed the computation of upper tolerance limit in balanced and unbalanced one-way random effects models, whereas Fonseca et al [3] performed it based in a similar ideas but in a tow-way nested mixed or random effects model. In case of random effects model, Fonseca et al [3] performed the computation of such interval only for the balanced data, whereas in the mixed effects case they dit it only for the unbalanced data. For the computation of twosided tolerance interval in models with mixed and/or random effects we recomend, for instance, Sharma and Mathew [7]. The purpose of this paper is the computation of upper and lower tolerance interval in a two-way nested mixed effects models in balanced data. For the case of unbalanced data, as mentioned above, Fonseca et al [3] have already computed upper tolerance interval. Hence, using the notions persented in Fonseca et al [3] and Krishnamoorthy and Mathew [4], we present some results on the construction of one-sided tolerance interval for the balanced case. Thus, in order to do so at first instance we perform the construction for the upper case, and then the construction for the lower case.

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Malignant mixed Müllerian tumours (malignant mixed mesodermal tumours, MMMT) of the uterus are metaplastic carcinomas with a sarcomatous component and thus they are also called carcinosarcomas. It has now been accepted that the sarcomatous component is derived from epithelial elements that have undergone metaplasia. The process that produces this metaplasia is epithelial to mesenchymal transition (EMT), which has recently been described as a neoplasia-associated programme shared with embryonic development and enabling neoplastic cells to move and metastasise. The ubiquitin proteasome system (UPS) regulates the turnover and functions of hundreds of cellular proteins. It plays important roles in EMT by being involved in the regulation of several pathways participating in the execution of this metastasis-associated programme. In this review the specifi c role of UPS in EMT of MMMT is discussed and therapeutic opportunities from UPS manipulations are proposed.

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This study was conducted to examine the distribution and nature of Fe oxides in plinthic soils on the sediments of Barreiras Group (in the state of Piauí) and Itapecuru Formation (in the state of Maranhão) in Northeastern Brazil. Four pedons were selected: a "plinthic, dystrophic, epieutrophic Gray Podzolic with low activity clay" and a "dystrophic Plinthosol with low activity clay" (both Plinthic Kandiustalfs) on the Barreiras sediments, as well as an "eutrophic Plinthosol with low activity clay" and an "allic Plinthosol with low activity clay" (both Plinthustalfs) on the Itapecuru sediments. Soil samples were fractionated into > 2 mm (pisoliths), water-stable aggregates (plinthite) and matrices; the aggregates and matrices were further fractionated into sand, silt and clay sizes. Dithionite extractable iron (Fe d) and aluminum (Al d), as well as oxalate extractable iron (Fe o), were determined for all fractions, and X-ray diffraction analyses were performed on the pisoliths. It was observed that the Plinthustalfs contain more iron oxides, exhibit more extensive plinthite development and have a greater potential for further plinthite development than the Kandiustalfs. The distribution of values for the Fe d indicates that plinthite formation and induration in all soils were accompanied by an enrichment of Fe oxides in all particle size fractions. This Fe segregation was accompanied by aggregation of particles leading to a greater degree of crystallinity, as indicated by analysis of the ratios of Al d:Fe d. Larger ratios of goethite to hematite, and relatively smaller amounts of silicates in the more mature pisoliths were revealed by X-ray diffraction analysis. Ratios of Al d:Fe d were larger in the Kandiustalfs than in the Plinthustalfs, and also larger than expected for Al-substituted Fe oxides. According to ratios of Al d:Fe d, Fe mobilization in all soils has likely occurred under reducing conditions, facilitated by organic matter on the soil surface.

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The impact of topography and mixed pixels on L-band radiometric observations over land needs to be quantified to improve the accuracy of soil moisture retrievals. For this purpose, a series of simulations has been performed with an improved version of the soil moisture and ocean salinity (SMOS) end-to-end performance simulator (SEPS). The brightness temperature generator of SEPS has been modified to include a 100-m-resolution land cover map and a 30-m-resolution digital elevation map of Catalonia (northeast of Spain). This high-resolution generator allows the assessment of the errors in soil moisture retrieval algorithms due to limited spatial resolution and provides a basis for the development of pixel disaggregation techniques. Variation of the local incidence angle, shadowing, and atmospheric effects (up- and downwelling radiation) due to surface topography has been analyzed. Results are compared to brightness temperatures that are computed under the assumption of an ellipsoidal Earth.

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In 2003, the Swiss guidelines to prevent vitamin K deficiency bleeding (VKDB) were adapted. As two oral doses (2 mg, hour/day 4) of mixed micellar VK preparation had failed to abolish late VKDB, a third dose (week 4) was introduced. This report summarizes the new guidelines acceptance by Swiss pediatricians and the results of a prospective 6-year surveillance to study their influence on the incidence of VKDB. The new guidelines acceptance by Swiss pediatricians was evaluated by a questionnaire sent to all pediatricians of the Swiss Society of Paediatrics. With the help of the Swiss Paediatric Surveillance Unit, the incidence of VKDB was monitored prospectively from July 1, 2005 until June 30, 2011. Over a 6-year period (458,184 live births), there was one case of early and four cases of late VKDB. Overall incidence was 1.09/10(5) (95 % confidence intervals (CI) 0.4-2.6). Late VKDB incidence was 0.87/10(5) (95 % CI 0.24-2.24). All four infants with late VKDB had an undiagnosed cholestasis at the time of bleeding; parents of 3/4 had refused VK prophylaxis, and in 1/4, the third VK dose had been forgotten. Compared with historical control who had received only two oral doses of mixed micellar VK (18 cases for 475,372 live births), the incidence of late VKDB was significantly lower with three oral doses (Chi(2),Yates correction, P = 0.007). CONCLUSION: VKDB prophylaxis with 3 × 2 mg oral doses of mixed micellar VK seems to prevent adequately infants from VKDB. The main risk factors for VKDB in breast-fed infants are parental VK prophylaxis refusal or an unknown cholestasis.

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Molecular species identification in mixed or contaminated biological material has always been problematic. We developed a simple and accurate method for mammal DNA identification in mixtures, based on interspecific mitochondrial DNA control region length polymorphism. Contrary to other published methods dealing with species mixtures, our protocol requires a single universal primer pair and amplification step, and is not based on a pre-defined panel of species. This protocol has been routinely employed by our laboratory for species identification in dozens of human and animal forensic caseworks. Six representative forensic caseworks involving the specific identification of mixed animal samples are reported in this paper, in order to demonstrate the applicability and usefulness of the method.

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The objective of this paper is to study selected components of the nutrient cycle of pure and mixed stands of native forest species of Atlantic Forest in southeastern Brazil. Tree diameter, height, above-ground biomass, and nutrient content were determined in 22-year-old stands. Litterfall, litter decomposition, and nutrient concentration were evaluated from August 1994 to July 1995. The following species were studied: Peltogyne angustiflora, Centrolobium robustum, Arapatiella psilophylla, Sclerolobium chrysophyllum, Cordia trichotoma, Macrolobium latifolium. The litter of a natural forest and a 40-year-old naturally regenerated second-growth forest was sampled as well. The mixed-species outmatched pure stands in height, stem volume and total biomass (29.4 % more). The greatest amount of forest litter was observed in the natural forest (9.3 Mg ha-1), followed by the mixed-species stand (7.6 Mg ha-1) and secondary forest (7.3 Mg ha-1), and least litterfall was measured in the pure C. robustum stand (5.5 Mg ha-1). Litterfall seasonality varied among species in pure stands (CV from 44.7 to 91.4 %), unlike litterfall in the mixed-tree stand, where the variation was lower (CV 31.2 %). In the natural and second-growth forest, litterfall varied by 57.8 and 34.0 %, respectively. The annual rate of nutrient return via litterfall varied widely among forest ecosystems. Differences were detected between forest ecosystems in both the litter accumulation and quantity of litterlayer nutrients. The highest mean nutrient accumulation in above-ground biomass was observed in mixed-species stands. The total nutrient accumulation (N + P + K+ Ca + Mg) ranged from 0.97 to 1.93 kg tree-1 in pure stands, and from 1.21 to 2.63 kg tree-1 in mixed-species stands. Soil fertility under mixed-species stands (0-10 cm) was intermediate between the primary forest and pure-stand systems. The litterfall rate of native forest species in a mixed-species system is more constant, resulting in a more continuous decomposition rate. Consequently, both nutrient availability and quantity of organic matter in the soil are higher and the production system ecologically more sustainable.

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A novel NO2 sensor based on (CdO)x(ZnO)1-x mixed-oxide thin films deposited by the spray pyrolysis technique is developed. The sensor response to 3-ppm NO2 is studied in the range 50°C-350°C for three different film compositions. The device is also tested for other harmful gases, such as CO (300 ppm) and CH4 (3000 ppm). The sensor response to these reducing gases is different at different temperatures varying from the response typical for the p-type semiconductor to that typical for the n-type semiconductor. Satisfactory response to NO2 and dynamic behavior at 230°C, as well as low resistivity, are observed for the mixed-oxide film with 30% Cd. The response to interfering gas is poor at working temperature (230°C). On the basis of this study, a possible sensing mechanism is proposed.

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The Brazilian System of Soil Classification (SiBCS) is a taxonomic system, open and in permanent construction, as new knowledge on Brazilian soils is obtained. The objective of this study was to characterize the chemical, physical, morphological, micro-morphological and mineralogical properties of four pedons of Oxisols in a highland toposequence in the upper Jequitinhonha Valley, emphasizing aspects of their genesis, classification and landscape development. The pedons occupy the following slope positions: summit - Red Oxisol (LV), mid slope (upper third) - Yellow-Red Oxisol (LVA), lower slope (middle third)- Yellow Oxisol (LA) and bottom of the valley (lowest third) - "Gray Oxisol" ("LAC"). These pedons were described and sampled for characterization in chemical and physical routine analyses. The total Fe, Al and Mn contents were determined by sulfuric attack and the Fe, Al and Mn oxides in dithionite-citrate-bicarbonate and oxalate extraction. The mineralogy of silicate clays was identified by X ray diffraction and the Fe oxides were detected by differential X ray diffraction. Total Ti, Ga and Zr contents were determined by X ray fluorescence spectrometry. The "LAC" is gray-colored and contains significant fragments of structure units in the form of a dense paste, characteristic of a gleysoil, in the horizons A and BA. All pedons are very clayey, dystrophic and have low contents of available P and a pH of around 5. The soil color was related to the Fe oxide content, which decreased along the slope. The decrease of crystalline and low- crystalline Fe along the slope confirmed the loss of Fe from the "LAC". Total Si increased along the slope and total Al remained constant. The clay fraction in all pedons was dominated by kaolinite and gibbsite. Hematite and goethite were identified in LV, low-intensity hematite and goethite in LVA, goethite in LA. In the "LAC", no hematite peaks and goethite were detected by differential X ray diffraction. The micro-morphology indicated prevalence of granular microstructure and porosity with complex stacking patterns.. The soil properties in the toposequence converged to a single soil class, the Oxisols, derived from the same source material. The landscape evolution and genesis of Oxisols of the highlands in the upper Jequitinhonha Valley are related to the evolution of the drainage system and the activity of excavating fauna.

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In the assignment game framework, we try to identify those assignment matrices in which no entry can be increased without changing the coreof the game. These games will be called buyer¿seller exact games and satisfy the condition that each mixed¿pair coalition attains the corresponding matrix entry in the core of the game. For a given assignment game, a unique buyerseller exact assignment game with the same core is proved to exist. In order to identify this matrix and to provide a characterization of those assignment games which are buyer¿seller exact in terms of the assignment matrix, attainable upper and lower core bounds for the mixed¿pair coalitions are found. As a consequence, an open question posed in Quint (1991) regarding a canonical representation of a ¿45o¿lattice¿ by means of the core of an assignment game can now be answered

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In this paper we describe the results of a simulation study performed to elucidate the robustness of the Lindstrom and Bates (1990) approximation method under non-normality of the residuals, under different situations. Concerning the fixed effects, the observed coverage probabilities and the true bias and mean square error values, show that some aspects of this inferential approach are not completely reliable. When the true distribution of the residuals is asymmetrical, the true coverage is markedly lower than the nominal one. The best results are obtained for the skew normal distribution, and not for the normal distribution. On the other hand, the results are partially reversed concerning the random effects. Soybean genotypes data are used to illustrate the methods and to motivate the simulation scenarios

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In this paper we analyse, using Monte Carlo simulation, the possible consequences of incorrect assumptions on the true structure of the random effects covariance matrix and the true correlation pattern of residuals, over the performance of an estimation method for nonlinear mixed models. The procedure under study is the well known linearization method due to Lindstrom and Bates (1990), implemented in the nlme library of S-Plus and R. Its performance is studied in terms of bias, mean square error (MSE), and true coverage of the associated asymptotic confidence intervals. Ignoring other criteria like the convenience of avoiding over parameterised models, it seems worst to erroneously assume some structure than do not assume any structure when this would be adequate.