38 research outputs found
Highly Entangled Ground States in Tripartite Qubit Systems
We investigate the creation of highly entangled ground states in a system of
three exchange-coupled qubits arranged in a ring geometry. Suitable magnetic
field configurations yielding approximate GHZ and exact W ground states are
identified. The entanglement in the system is studied at finite temperature in
terms of the mixed-state tangle tau. By adapting a steepest-descent
optimization algorithm we demonstrate that tau can be evaluated efficiently and
with high precision. We identify the parameter regime for which the equilibrium
entanglement of the tripartite system reaches its maximum.Comment: 4 pages, 2 figure
Antithrombin attenuates myocardial dysfunction and reverses systemic fluid accumulation following burn and smoke inhalation injury: a randomized, controlled, experimental study
Introduction: We hypothesized that maintaining physiological plasma levels of antithrombin attenuates myocardial dysfunction and inflammation as well as vascular leakage associated with burn and smoke inhalation injury. Therefore, the present prospective, randomized experiment was conducted using an established ovine model. Methods: Following 40% of total body surface area, third degree flame burn and 4 × 12 breaths of cold cotton smoke, chronically instrumented sheep were randomly assigned to receive an intravenous infusion of 6 IU/kg/h recombinant human antithrombin (rhAT) or normal saline (control group; n = 6 each). In addition, six sheep were designated as sham animals (not injured, continuous infusion of vehicle). During the 48 h study period the animals were awake, mechanically ventilated and fluid resuscitated according to standard formulas. Results: Compared to the sham group, myocardial contractility was severely impaired in control animals, as suggested by lower stroke volume and left ventricular stroke work indexes. As a compensatory mechanism, heart rate increased, thereby increasing myocardial oxygen consumption. In parallel, myocardial inflammation was induced via nitric oxide production, neutrophil accumulation (myeloperoxidase activity) and activation of the p38-mitogen-activated protein kinase pathway resulting in cytokine release (tumor necrosis factor-alpha, interleukin-6) in control vs. sham animals. rhAT-treatment significantly attenuated these inflammatory changes leading to a myocardial contractility and myocardial oxygen consumption comparable to sham animals. In control animals, systemic fluid accumulation progressively increased over time resulting in a cumulative positive fluid balance of about 4,000 ml at the end of the study period. Contrarily, in rhAT-treated animals there was only an initial fluid accumulation until 24 h that was reversed back to the level of sham animals during the second day. Conclusions: Based on these findings, the supplementation of rhAT may represent a valuable therapeutic approach for cardiovascular dysfunction and inflammation after burn and smoke inhalation injury.<br
Whiteness and the Rejected Other in \u3cem\u3eThe Sun Also Rises\u3c/em\u3e
On the novel’s ambiguous treatment of the other, especially Jews and homosexuals. Argues that a blanket reading of the novel as anti-Semitic and homophobic ignores the subtleties of Jake’s character
Performing the Feminine in \u3cem\u3eA Farewell to Arms\u3c/em\u3e
On gender construction, analyzing Catherine as an example of Hemingway’s critique of gender roles and their social function. Argues that Catherine’s ability to don a mask of femininity as a tool for self-preservation proves that she is a woman of agency who ultimately exhibits masculine grace under pressure in a chaotic modern world
Effects of a dual endothelin-1 receptor antagonist on airway obstruction and acute lung injury in sheep following smoke inhalation and burn injury
A B S T R A C T Studies have suggested that ET-1 (endothelin-1) is associated with lung injury, airway inflammation and increased vascular permeability. In the present study we have tested the hypothesis that treatment with a dual ET-1 receptor antagonist will decrease airway obstruction and improve pulmonary function in sheep with combined S + B (smoke inhalation and burn) injury. Twelve sheep received S + B injury using the following protocol: six sheep were treated with tezosentan, an ET A and ET B receptor antagonist, and six sheep received an equivalent volume of vehicle. Physiological and morphological variables were assessed during the 48 h study period and at the end of the study. There was no statistically significant difference in the PaO 2 /FiO 2 (partial pressure of O 2 in arterial blood/fraction of O 2 in the inspired gas) ratio of the tezosentan-treated animals compared with controls; however, lung lymph flow was significantly higher (P < 0.05) in the treated animals. PVRI (pulmonary vascular resistance index) was significantly reduced (P < 0.05) in the tezosentan-treated animals. Assessment of NOx (nitric oxide metabolite) levels in plasma and lymph showed significantly elevated (P < 0.05) levels in the tezosentan-treated animals compared with levels in untreated sheep. The degree of bronchial obstruction was similar in both treated and control sheep; however, bronchiolar obstruction was reduced in sheep treated with tezosentan. Histopathologically, no difference in the degree of parenchymal injury was detected. In conclusion, administration of a dual ET-1 receptor antagonist prevented an increase in PVRI after injury and reduced the degree of bronchiolar obstruction in sheep with S + B; however, treated sheep showed higher levels of NOx and increased lung lymph flow. Tezosentan treatment was ineffective in protecting against acute lung injury in this model
Natural history of primary paediatric optic nerve sheath meningioma: case series and review
PURPOSE: To study the natural history, clinical and radiological characteristics of primary paediatric optic nerve sheath meningioma (PPONSM).
METHODS: Retrospective study of eight paediatric patients who were treated between 1994 and 2016 at the University Hospital Zurich, Switzerland and the Royal Adelaide Hospital, Australia. Clinical records and imaging studies were reviewed.
RESULTS: The mean age at presentation was 11 years (range: 6-17 years). There were six female patients and two male patients. 2/8 patients had associated neurofibromatosis type 2.Patients were followed up for 71-297 months (mean 156±70 months). 6/8 patients were observed through the course of their disease and 2/8 patients were treated with radiotherapy. 2/8 patients who were observed had minimal change in vision and did not experience tumour growth after long-term follow-up.
CONCLUSIONS: This is the largest PPONSM case series with long-term data on patients treated conservatively. We highlight that a small subset of these tumours are indolent and can be managed using observation alone
Human mesenchymal stem cells reduce the severity of acute lung injury in a sheep model of bacterial pneumonia
Background Human bone marrow-derived mesenchymal stem (stromal) cells (hMSCs) improve survival in mouse models of acute respiratory distress syndrome (ARDS) and reduce pulmonary oedema in a perfused human lung preparation injured with Escherichia coli bacteria. We hypothesised that clinical grade hMSCs would reduce the severity of acute lung injury (ALI) and would be safe in a sheep model of ARDS. Methods Adult sheep (30-40 kg) were surgically prepared. After 5 days of recovery, ALI was induced with cotton smoke insufflation, followed by instillation of live Pseudomonas aeruginosa (2.51011 CFU) into both lungs under isoflurane anaesthesia. Following the injury, sheep were ventilated, resuscitated with lactated Ringer's solution and studied for 24 h. The sheep were randomly allocated to receive one of the following treatments intravenously over 1 h in one of the following groups: (1) control, PlasmaLyte A, n=8; (2) lower dose hMSCs, 5106 hMSCs/kg, n=7; and (3) higher-dose hMSCs, 10106 hMSCs/kg, n=4. Results By 24 h, the PaO2/FiO2 ratio was significantly improved in both hMSC treatment groups compared with the control group (control group: PaO2/FiO2 of 9715 mm Hg; lower dose: 28855 mm Hg (p=0.003); higher dose: 3272 mm Hg ( p=0.003)). The median lung water content was lower in the higher-dose hMSCtreated group compared with the control group (higher dose: 5.0 g wet/g dry [IQR 4.9-5.8] vs control: 6.7 g wet/g dry [IQR 6.4-7.5] ( p=0.01)). The hMSCs had no adverse effects. Conclusions Human MSCs were well tolerated and improved oxygenation and decreased pulmonary oedema in a sheep model of severe ARDS.9999