X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) techniques at both Fe and Co K-edges were used to investigate the formation of CoFe2O4 nanoparticles embedded ...in a silica aerogel matrix as a function of calcination temperature and CoFe2O4 content. In particular, nanocomposite aerogels containing relative CoFe2O4 amounts of 5 and 10 wt % and calcined at 450, 750, and 900 °C were studied. The evolution of the nanophase with calcination temperatures depends on the composition. In the sample containing 10 wt % of nanophase, results indicate that CoFe2O4 nanocrystals were formed after calcination at 750 °C, whereas in the sample containing 5 wt % of nanophase, they were obtained only after calcination at 900 °C. Quantitative determination of the distribution of the iron and cobalt phase in the octahedral and tetrahedral sites of the spinel structure shows that cobalt ferrite prepared by sol−gel has a partially inverted spinel structure with a degree of inversion around 0.70.
A series of FeCo-SiO(2) nanocomposite aerogels having different FeCo loadings of 3, 5, and 8 wt % were prepared using a novel urea-assisted sol-gel route. The size of the nanoparticles, which was ...estimated using Scherrer analysis of the main peak of the x-ray diffraction pattern, varies from 3 to 8 nm. X-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) techniques at both Fe and Co K edges were used to investigate the structure of the FeCo nanoparticles. EXAFS and XANES show that FeCo nanoparticles have the typical bcc structure. Evidence of oxidation was observed in low FeCo content aerogels. Spatially resolved electron energy loss spectroscopy analysis suggests the formation of a passivation layer of predominantly iron oxide.
Undifferentiated pleomorphic sarcoma (UPS) of the breast is an extremely rare, but aggressive subtype of sarcoma that can develop in radiotherapy (RT)-treated breast cancer patients. Due to the low ...incidence, there are many uncertainties regarding the adequate management of these tumors. We present a rare case of radiation-induced UPS in a 63-year-old woman who had undergone breast conserving therapy for invasive ductal carcinoma of the left breast, six years prior to presentation.
A 63-year-old woman presented with a rapidly growing left breast mass. She had been diagnosed with invasive ductal carcinoma of the left breast for which she underwent a left upper outer quadrantectomy and ipsilateral axillary dissection followed by RT, six years previously. During her routine oncologic follow-up, the mammography revealed a dense, nodular opacity with microcalcifications. The breast ultrasound (US) confirmed the presence of the nodule. US-guided fine needle aspiration biopsy was performed and the diagnosis of UPS was made, the reason for which the patient underwent wide local excision of the left breast.
The diagnosis of RT-induced UPS is challenging and often missed due to the low incidence, long latency period, unspecific imaging findings, and difficulties in clinical and histological detection of these lesions. These tumors should be considered in differential diagnoses of rapidly-growing breast masses in previously RT-treated breast cancer patients, as they can mimic the local recurrence of the primary tumor. Since the prevalence of breast-conserving surgery followed by RT has been increasing, the careful monitoring of at risk patients is of utmost importance, as UPSs are highly aggressive tumors associated with very poor outcomes.
Nanocomposites containing FeCo alloy nanoparticles dispersed in a highly ordered cubic mesoporous silica (SBA-16) matrix were prepared using two different synthetic methods, co-precipitation and ...impregnation. Extended X-ray Absorption Spectroscopy (EXAFS) technique at both Fe and Co K-edges was used to investigate the structure of FeCo nanoparticles and the presence of additional disordered oxide phases. EXAFS technique gives evidence of differences in the oxidation degree of the FeCo nanoparticles depending on the synthetic method used.
Fecaloma is common in patients with damage to the autonomic nervous system in the large bowel associated with Chagas disease (inflammatory and neoplastic) or Hirschprung's disease, in psychiatric ...patients and, more commonly, in elderly patients suffering with chronic constipation. Symptoms of fecaloma are usually nonspecific. Clinical examination can give the appearance of an abdominal tumor. Most cases of fecaloma are treated conservatively with digital evacuation and enemas. In severe and unremitting cases, surgery is required to prevent significant complications. Fecaloma should be considered in the differential diagnosis of any patient with history of chronic constipation and abdominal mass. We present the clinical case of an 85-year-old man with a history of chronic constipation presented to the emergency room with vague abdominal pain of 2 days' duration. An erect abdominal X-ray and computed tomography revealed a supergiant faecaloma extending from the pubis up to the diaphragm associated to a megarectum and megacolon. The patient was treated successfully with digital evacuation and enemas.
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