48 research outputs found
Striped instability of a holographic Fermi-like liquid
We consider a holographic description of a system of strongly-coupled
fermions in 2+1 dimensions based on a D7-brane probe in the background of
D3-branes. The black hole embedding represents a Fermi-like liquid. We study
the excitations of the Fermi liquid system. Above a critical density which
depends on the temperature, the system becomes unstable towards an
inhomogeneous modulated phase which is similar to a charge density and spin
wave state. The essence of this instability can be effectively described by a
Maxwell-axion theory with a background electric field. We also consider the
fate of zero sound at non-zero temperature.Comment: 16 pages, 9 figures; v2: added discussion and one figure. Typos
correcte
Pituitary insufficiency after operation of supratentorial intra- and extraaxial tumors outside of the sellar–parasellar region?
Recent studies investigating pituitary function after non-sellar brain tumor surgery showed that up to 38.2% of patients have pituitary insufficiency (PI). It has been assumed that the operation causes the PI, but preoperative hormone testing, which would have been necessary to prove this assumption, was not performed. The objective of this study is to answer the question if indeed microsurgery is the culprit of PI in patients with operatively treated non-sellar brain tumors. In this prospective trial, 54 patients with supratentorial non-sellar tumors were included. The basal levels of cortisol, prolactin, testosterone, estrogen, IGF-1, fT3, fT4, STH, TSH, ACTH, FSH, and LH were recorded preoperatively on days 1 and 7 after surgery. If basal hormone screening revealed an abnormality, a releasing hormone assay was performed. Before surgery, 24 of the 54 patients (44.4%) already had PI. Additional 25 patients showed either hypocortisolism or hypothyreoidism. As those patients had been pre-treated with dexamethasone and l-thyroxine, these findings were considered not to represent PI but drug effects. Hormone testing on days 1 and 7 after surgery revealed no changes. With 44.4% PI is a frequent finding in brain tumor patients already before surgery. The factors causing preoperative PI remain yet to be identified. The endocrine results after surgery are unchanged which rules out that surgery is the cause of PI
Personality changes and return to work after severe traumatic brain injury: a prospective study
Early use of Xeomin neurotoxin for local anti-spasticity therapy for pes equines after acquired brain injury (ABI)
Primary objective: The acute management of spasticity following ABI is challenging. Contractures can occur during the acute phases of illness. The joints most affected are the shoulders and the ankles. Research design: A case study of a 48-year-old female patient who received local chemoneurolytic anti-spasticity therapy following a severe subarachnoid haemorrhage for pes equines deformity is presented to illustrate the role of focal neurotoxin therapy. Methods and procedures: The increasing spasticity in her legs was observed and could not be effectively treated with oral anti-spasticity agents or intensive physiotherapy. As spasticity increased (Modified Ashworth Scale 4), mobility of the right foot continued to deteriorate, leading to indication for local anti-spasticity treatment with Xeomin neurotoxin. The spastic pes equinus was injected with Xeomin (R) using a total dose of 150 U. Main outcomes and results: On the 6th day after injection, a gradual reduction in spasticity was observed in the injected muscle (Modified Ashworth Scale 1-2) and an increasing improvement in joint mobility. Conclusions: Early local anti-spasticity treatment with Xeomin is effective treatment. The cost of the intervention would appear to be high, but if one compares it with the costs of conservative treatment, it is not more expensive