81 research outputs found

    Mineral and textural transformations in mixtures of Al-rich and Al–K-rich clays with firing: Refractory potential of the fired products

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    The present work analyses a set of cylinders manufactured by pressing and fired from 1000 °C to 1270 °C, which are composed of pure Al-rich rocks (bauxite) and mixtures of bauxite with Al–K-rich clays. The aim of the study is to determine the mineral and textural transformations that take place in the mixtures with firing and their influence on the physical properties of the final products in order to evaluate their refractory potential by comparing them with various fired commercial bauxites. To this end, raw and fired samples were analysed by X-ray diffraction, X-ray fluorescence, and optical and field emission scanning electron microscopy, and significant physical properties (e.g. density, linear shrinkage, porosity, colour, water absorption, thermal conductivity and point load resistance) were determined in the fired cylinders. The raw bauxite was mainly formed by boehmite, kaolinite and hematite whereas the illite- and kaolinite-rich clay was formed by quartz, illite and kaolinite. Kaolinite, illite and boehmite are not detected at 1000 °C and, from this temperature upwards, mullite, corundum, ¿-Al2O3, hercynite, ilmenite, cristobalite and vitreous phase are formed. Changes in physical properties with rising temperature are associated with the mineralogical changes. The increases in density and linear shrinkage are related to the formation of vitreous phase and the crystallization of mullite, and correlate with the decrease in porosity, water absorption and thermal conductivity. The changes in the colour of the samples are related to the hematite content at each temperature, whereas the point load resistance is greater with higher corundum content. Both the firing temperature and the clay content play an important role in the refractory potential of the mixtures, since samples mixed with illite- and kaolinite-rich clay present similar properties at lower temperatures to those of the fired commercial bauxites

    Duodenal metastasis of alveolar soft part sarcoma

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    Aveolar soft part sarcoma is a rare tumor responsible for about 1% of all soft tissue sarcomas, affecting mostly adolescents and young adults. ASPS has curious patterns of metastatic spread, with seldom lymph node involvement. Lung, bone and brain are the most common metastatic places. Small bowel metastasis are infrequent, having found reported only one case of duodenal metastasis with polypous appearance. We describe a case of duodenal metastasis presenting as abdominal mass five years after initial diagnosis of alveolar soft part sarcoma

    Dysfunctional LAT2 Amino Acid Transporter Is Associated With Cataract in Mouse and Humans.

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    Cataract, the loss of ocular lens transparency, accounts for ∼50% of worldwide blindness and has been associated with water and solute transport dysfunction across lens cellular barriers. We show that neutral amino acid antiporter LAT2 (Slc7a8) and uniporter TAT1 (Slc16a10) are expressed on mouse ciliary epithelium and LAT2 also in lens epithelium. Correspondingly, deletion of LAT2 induced a dramatic decrease in lens essential amino acid levels that was modulated by TAT1 defect. Interestingly, the absence of LAT2 led to increased incidence of cataract in mice, in particular in older females, and a synergistic effect was observed with simultaneous lack of TAT1. Screening SLC7A8 in patients diagnosed with congenital or age-related cataract yielded one homozygous single nucleotide deletion segregating in a family with congenital cataract. Expressed in HeLa cells, this LAT2 mutation did not support amino acid uptake. Heterozygous LAT2 variants were also found in patients with cataract some of which showed a reduced transport function when expressed in HeLa cells. Whether heterozygous LAT2 variants may contribute to the pathology of cataract needs to be further investigated. Overall, our results suggest that defects of amino acid transporter LAT2 are implicated in cataract formation, a situation that may be aggravated by TAT1 defects

    Prolongation of survival of dogs with oral malignant melanoma treated by en bloc surgical resection and adjuvant CSPG4-antigen electrovaccination

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    Reported post-surgery 1-year survival rate for oral canine malignant melanoma (cMM) is around 30%; novel treatments are needed as the role of adjuvant chemotherapy is unclear. This prospective study regards adjuvant electrovaccination with human chondroitin sulfate proteoglycan-4 (hCSPG4)-encoded plasmid in 23 dogs with resected II/III-staged CSPG4-positive oral cMM compared with 19 dogs with resected only II/III-staged CSPG4-positive oral cMM. Vaccination resulted in 6-, 12-, 18- and 24-month survival rate of 95.6, 73.9, 47.8 and 30.4%, respectively [median survival time (MST) 684 days, range 78–1694, 8 of 23 dogs alive] and 6-, 12-, 18- and 24-month disease-free interval (DFI) rate of 82.6, 47.8, 26.1 and 17.4%, respectively (DFI 477 days, range 50–1694). Non-vaccinated dogs showed 6-, 12-, 18- and 24-month survival rate of 63.2, 26.3, 15.8 and 5.3%, respectively (MST 200 days, range 75–1507, 1 of 19 dogs alive) and 6-, 12-, 18- and 24-month DFI rate of 52.6, 26.3, 10.5 and 5.3%, respectively (DFI 180 days, range 38–1250). Overall survival and DFI of vaccinated dogs was longer in those <20 kg. In vaccinated and non-vaccinated dogs local recurrence rate was 34.8 and 42%, respectively while lung metastatic rate was 39 and 79%, respectively

    ¿Es la dirección escolar un trabajo apasionante? Evaluación de la pasión en directivos de Chile y Cataluña

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    According to the literature, the increase in complexity in the direction and management of the centers could explain the scarcity of candidates for the school direction and the exhaustion and desertion of principals. However, that principals are satisfied and passionate about their work. The aim of this article is to analyse the levels of passion of the school management professionals using the Passion Scale (Marsh et al., 2013) and its relationship with professional variables. The results show high levels of passion and harmonious passion among the subjects of the sample, both in Chile and in Catalonia (Spain).Según la literatura, el incremento de la complejidad en la gestión de los centros educativos podría explicar la escasez de candidaturas para la dirección escolar y el agotamiento y deserción de directivos. No obstante, los directivos se muestran satisfechos y apasionados por su trabajo. El objetivo de este estudio es analizar los niveles de pasión en profesionales de la dirección escolar mediante la escala de la Pasión (Marsh et al., 2013) y su relación con variables profesionales. Los resultados muestran altos niveles de pasión y pasión armoniosa entre los sujetos de la muestra, tanto en Chile como en Cataluña

    Hiperplasia suprarrenal congénita debida a deficiencia de 17a-hidroxilasa: a propósito de una nueva mutación en el gen CYP17A1

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    La enzima P450c17 cataliza 2 reacciones diferentes: 17a-hidroxilación de la progesterona y pregnenolona y segmentación de la unión del carbono 17-20 a partir de la 17,20 liasa para producir andrógenos suprarrenales. Esta enzima está codificada por el gen CYP17A1. Se presenta una paciente de 14 años con retraso en el desarrollo puberal y presión arterial elevada para su talla y edad. Cariotipo 46,XX. En el estudio hormonal destaca hipogonadismo hipergonadotropo, así como una insuficiencia suprarrenal y exceso mineralocorticoideo. El estudio genético mostró una mutación en homozigosis en el gen CYP17A1 (c.753+1G>A), no descrita previamente, la cual es responsable de la fisiopatología de la deficiencia de 17a-hidroxilasa. Esta entidad es una forma rara de hiperplasia suprarrenal congénita. Normalmente la enfermedad suele pasar desapercibida hasta la adolescencia o el inicio de la vida adulta y se debería sospechar ante individuos 46,XY con genitales ambiguos o 46,XX con retraso puberal que asocia hipertensión y/o hipopotasemia. P450c17 enzyme catalyses two different reactions: the 17a-hydroxylation of progesterone and pregnenolone, and segmenting the carbon 17-20 binding from the 17,20 lyase producing adrenal androgens. This enzyme is coded by the CYP17A1 gene. The case is presented of a 14 year old patient with delayed pubertal development and a high blood pressure for height and age. 46,XX karyotype. Hormonal studies highlighted hypergonadotropic hypogonadism, adrenal insufficiency and mineralocorticoid excess. Subsequent genetic studies showed a homozygous mutation in the CYP17A1 gene (c.753+G>A), not previously described, which is responsible for the pathophysiology of 17a-hydroxylase deficiency. This entity is a rare form of congenital adrenal hyperplasia. The disease often goes unnoticed until adolescence or early adult life, and should be suspected in 46,XY individuals with ambiguous genitalia or 46,XX with delayed puberty associated with hypertension and/or hypokalaemia

    Role of image-guided fine-needle aspiration biopsy in the management of patients with splenic metastasis

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    BACKGROUND: Splenic metastases are very rare and are mostly diagnosed at the terminal phase of the disease or at the time of autopsy. The cytohistological diagnosis, when done, is made prevalently by splenectomy. Reports on splenic percutaneous biopsies in the diagnosis of splenic metastasis are fragmentary and very poor. The aims of this study are to analyse retrospectively the accuracy, safety and the clinical impact of ultrasound (US)-guided fine-needle aspiration biopsy (UG-FNAB) in patients with suspected splenic metastasis. METHODS: A retrospective analysis of 1800 percutaneous abdominal biopsies performed at our institute during the period from 1993 to 2003 was done and 160 patients that underwent splenic biopsy were found. Among these 160 patients, 12 cases with the final diagnosis of solitary splenic metastases were encountered and they form the basis of this report. The biopsies were performed under US guidance using a 22-gauge Chiba needle. All the patients underwent laboratory tests, CT examination of the abdomen and chest, US examination of abdomen and pelvis. RESULTS: There were 5 women and 7 men, median age 65 years (range 48–80). Eight patients had a known primary cancer at the time of the diagnosis of splenic metastasis: 3 had breast adenocarcinoma, 2 colon adenocarcinoma, 2 melanoma and 1 lung adenocarcinoma. Four patients were undiagnosed at the time of the appearance of splenic metastasis and subsequent investigations showed adenocarcinoma of the lung in 2 patients and colon adenocarcinoma in the remaining 2. There was a complete correspondence between the US and Computed Tomography (CT) in detecting focal lesions of the spleen. The splenic biopsies allowed a cytological diagnosis of splenic metastasis in all the 12 patients and changed clinical management in all cases. Reviewing the 160 patients that underwent UG-FNAB of the spleen we found no complications related to the biopsies. CONCLUSION: These results indicate that UG-FNAB is a successful technique for diagnosis of splenic metastasis allowing an adequate treatment of the affected patients
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