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Context: Spontaneous spinal epidural hematoma (SSEH) is a rare idiopathic condition that leads to acute onset of neurological deficits, which if not recognized early can have catastrophic consequences. The definition and pathophysiology of this condition remain controversial. High index of suspicion followed by T2-weighted gradient echo sequences are particularly useful in early diagnosis. Management consists of prompt surgical decompression of the hematoma though a recent trend is toward non-surgical treatment. Findings: A 70-year-old man presented with acute onset neck pain with a radicular component and rapidly progressive quadriparesis. Magnetic resonance imaging revealed a posteriorly located cervical extradural hematoma with cord compression that was promptly evacuated. Functional recovery to near normal function occurred within 24 hours of surgery. Conclusion: SSEH in its true idiopathic form is a rare pathologic entity. Because of the high risk of poor outcome without treatment, SSEH should be a diagnostic possibility when presentation is even slightly suggestive. Prompt surgical evacuation of the hematoma leads to a favorable neurological outcome, whereas delay in treatment can be disastrous. The role of conservative management needs to be proven and should be tailored on an individual basis.

Fine particles of cobalt ferrite were synthesized by the sol-gel method. Subsequent heat treatment at different temperatures yielded cobalt ferrites having different grain sizes. X-ray diffraction studies were carried out to elucidate the structure of all the samples. Dielectric permittivity and ac conductivity of all the samples were evaluated as a function of frequency, temperature and grain size. The variation of permittivity and ac conductivity with frequency reveals that the dispersion is due to Maxwell-Wagner type interfacial polarization in general, with a noted variation from the expected behaviour for the cold synthesized samples. High permittivity and conductivity for small grains were explained on the basis of the correlated barrier-hopping model.

Background: No consensus exists regarding the management of hydrocephalus in children with posterior fossa tumors before, during or after surgery. In the present study we analyze the factors that predispose to persistent hydrocephalus and the need for a postoperative cerebrospinal fluid (CSF) diversion procedure. Methods: Pediatric patients who underwent surgery for posterior fossa tumors with hydrocephalus at our hospital were reviewed to evaluate the need for a postoperative CSF diversion procedure. Patients having undergone CSF diversion preoperatively were excluded from the study group. The case records of 84 patients were reviewed. The factors evaluated included age at diagnosis, duration of symptoms, severity of preoperative hydrocephalus, tumor size, tumor location, tumor histology, extent of tumor resection and postoperative complications that could be related to CSF circulation disorders. Results: At the time of presentation, 80/84 (95.2%) patients had symptomatic hydrocephalus; 25/84 (29.8%) patients required a CSF diversion procedure in the postoperative period. Children presenting with symptom duration of less than 3 months had a significantly higher requirement for postoperative CSF diversion in comparison to those with longer symptomatology (p = 0.016). Evan’s index and frontal and occipital horn ratio on preoperative imaging were found to correlate closely with the need for postoperative shunt (p = 0.001 and p < 0.001, respectively). The requirement for shunt was statistically higher in patients with midline tumors in comparison to laterally placed lesions (p = 0.04) and in children with medulloblastoma (p < 0.001) and ependymoma (p = 0.016) as the tumor subtypes. Children who underwent intraoperative external ventricular drainage (EVD) had a shunt insertion rate of 39.6% compared with 16.7% of those who did not have an EVD (p < 0.001). Patients with meningitis and pseudomeningocele in the postoperative period had a statistically significant higher risk of shunt requirement (p = 0.008 and p = 0.016, respectively). The mean age at diagnosis and the extent of tumor resection did not correlate with the need for CSF diversion. Conclusion: The fact that less than one-third of patients require a CSF diversion after posterior fossa tumor resection refutes the role of prophylactic endoscopic third ventriculostomy. Awareness regarding the factors that can predict persistent postoperative hydrocephalus is essential for the surgeon during patient counseling and surgical planning, and also in deciding the intensity of postoperative clinical and radiological monitoring.

We have measured the dielectric properties of nickel ferrite (NiFe 2 O 4 ) synthesized by the micelles mixing method, prepared in suspension of coconut oil and annealing for 4 h at different temperatures. The as-grown ferrites presented highly amorphous X-ray spectrum. Post preparation annealing was applied to induce the increase in the size of the nanoparticles in order to tune the dielectric responses of the samples at the microwave frequencies.The X-ray diffraction (XRD) was applied to investigate the nanoparticle size dependence on the annealing temperature, allowing the correlation between the nanoparticle size and the observed microwave dielectric response.The micelles mixing method of preparation is then a cheap procedure to obtain high quality nanostructured nickel ferrites with low dielectric losses, and dielectric constant between 2.4 and 3.6. Zn-substituted Ni-Mg ferrites, J Magn Magn Mater 192 (1999), 305-313. 11. E.M. Mohammed, K.A. Malini, P. Kurian, and M.R. Anantharaman, Modification of dielectric and mechanical properties of rubber