Most quantum States are too entangled to be useful as computational resources

It is often argued that entanglement is at the root of the speedup for quantum compared to classical computation, and that one needs a sufficient amount of entanglement for this speedup to be manifest. In measurement-based quantum computing, the need for a highly entangled initial state is particularly obvious. Defying this intuition, we show that quantum states can be too entangled to be useful for the purpose of computation, in that high values of the geometric measure of entanglement preclude states from offering a universal quantum computational speedup. We prove that this phenomenon occurs for a dramatic majority of all states: the fraction of useful n-qubit pure states is less than exp(-n;{2}). This work highlights a new aspect of the role entanglement plays for quantum computational speedups.

Selective amygdalohippocampectomy: surgical outcome in children versus adults

INTRODUCTION

The objective of the study was to review our experience with selective amygdalohippocampectomy (SAH) in children and adults with intractable temporal lobe epilepsy.

METHODS

A retrospective case series was used in the setting of a tertiary care hospital which provides epilepsy care to both children and adults. All patients underwent a selective amygdalohippocampectomy procedure and had at least one year of follow-up. Adults and children were divided into two groups and the data was compared between children and adults.

RESULTS

Twenty three patients, 9 children and 14 adults were studied. Age of surgery varied from 6 to 58 years. Surgical outcome was variable between the two groups. Amongst the children, three patients (33%) were seizure-free (Engel Class I), two patients (22%) had rare seizures (Engel Class II), one patient (11%) had a worthwhile decrease in seizures (Engel class III) and three patients (32%) had refractory seizures that required re-operation with an anterior temporal lobectomy. This differed from the adults, who all had a good outcome. Ten patients (71%) were seizure-free (Engel Class I) and the remainder (29%) had rare seizures (Engel Class II).

CONCLUSION

Selective amygdalohippocampectomy can lead to excellent seizure surgical outcome in adults with refractory temporal lobe epilepsy. However, preliminary results show less favorable results in children. The difference is probably related to the different pathology between the two groups. Anterior temporal lobe resection may prove to be a more successful operation than SAH in children with intractable temporal lobe epilepsy.

Mathematical Model Creation for Cancer Chemo-Immunotherapy

One of the most challenging tasks in constructing a mathematical model of cancer treatment is the calculation of biological parameters from empirical data. This task becomes increasingly difficult if a model involves several cell populations and treatment modalities. A sophisticated model constructed by de Pilliset al.,Mixed immunotherapy and chemotherapy of tumours: Modelling, applications and biological interpretations, J. Theor. Biol. 238 (2006), pp. 841–862; involves tumour cells, specific and non-specific immune cells (natural killer (NK) cells, CD8+T cells and other lymphocytes) and employs chemotherapy and two types of immunotherapy (IL-2 supplementation and CD8+T-cell infusion) as treatment modalities. Despite the overall success of the aforementioned model, the problem of illustrating the effects of IL-2 on a growing tumour remains open. In this paper, we update the model of de Pilliset al.and then carefully identify appropriate values for the parameters of the new model according to recent empirical data. We determine new NK and tumour antigen-activated CD8+T-cell count equilibrium values; we complete IL-2 dynamics; and we modify the model in de Pilliset al.to allow for endogenous IL-2 production, IL-2-stimulated NK cell proliferation and IL-2-dependent CD8+T-cell self-regulations. Finally, we show that the potential patient-specific efficacy of immunotherapy may be dependent on experimentally determinable parameters.

Novel schemes for measurement-based quantum computation

We establish a framework which allows one to construct novel schemes for measurement-based quantum computation. The technique develops tools from many-body physics-based on finitely correlated or projected entangled pair states-to go beyond the cluster-state based one-way computer. We identify resource states radically different from the cluster state, in that they exhibit nonvanishing correlations, can be prepared using nonmaximally entangling gates, or have very different local entanglement properties. In the computational models, randomness is compensated in a different manner. It is shown that there exist resource states which are locally arbitrarily close to a pure state. We comment on the possibility of tailoring computational models to specific physical systems.

Simulation of discontinuous damage incorporating residual stresses in circumferentially overstretched atherosclerotic arteries

When a balloon-angioplasty is performed, the arterial wall is overstretched and thereby damaged, which leads to a stiffness reduction in the arterial layers. An anisotropic damage model able to reflect the main damage mechanisms in overstretched arterial walls is used in combination with a polyconvex hyperelastic stored energy function. Furthermore, a method for the incorporation of residual stresses present in the wall of unloaded configurations is applied. The energy describes the anisotropic hyperelastic behavior of arteries under physiological conditions. Due to the assumption that the rupture of cross-bridges between collageneous micro-fibrils is responsible for the damage inside arterial walls, the damage function is applied to that part of the energy only which is associated to the fiber elasticity. For the incorporation of the residual stresses into the simulation, we apply a method which consists of two simulation steps. Finally, a numerical simulation of the overstretching of a simplified atherosclerotic artery is performed taking into account residual stresses.

Molecular analysis of two uncharacterized sequence variants of the VHL gene

Mutations in the VHL gene cause von Hippel-Lindau disease, a cancer predisposing syndrome characterized by a variety of benign and malignant neoplasms. We report the molecular characterization of two sequence variants of the VHL gene: a synonymous substitution c.462 A>C in exon 2 and a duplication of 11 bp in the promoter region (c.-65_-55dup11). The first variant is a pathogenic mutation because, although it does not change the sense of the affected codon, it causes skipping of exon 2 in the affected allele by altering the splicing consensus site at the 3' end of exon 2. The 11 bp duplication represents a nonpathogenic variant. In fact, although it affects a critical region of the VHL promoter, it was found in healthy controls, and we show that carrier individuals express both VHL alleles at equimolar levels. Our data underline the importance of careful evaluation of the potential pathogenicity of sequence variants that may not belong to the obvious disease-causing mutation categories, or that affect relevant regulatory regions. mRNA analysis will be required to ultimately resolve this issue.

Laparoscopic adrenalectomy

BACKGROUND

Soon after its introduction, laparoscopic adrenalectomy (LA) became the procedure of choice in the surgical management of most adrenal tumors. The aim of this study was to assess the outcome and learning curve of the first 100 cases operated by the same surgical team.

METHODS

Retrospective analysis of prospectively collected data of 100 consecutive LAs was performed. The parameters studied were indication for surgery, side and length of operation, intra- and postoperative complications, size of tumor, conversion to open surgery, final diagnosis, and length of stay.

RESULTS

Between 1996 and 2002, 100 LAs were performed in 90 patients. The procedures included 45 left, 35 right, and 10 bilateral resections for pheochromocytoma (29), Cushings syndrome (27), Conns syndrome (16), nonfunctioning adenoma (13), and others (5). Mean tumor size was 4.16 cm (range, 0.3-11). Overall major morbidity occurred in eight patients (9%); there was one mortality due to cerebrovascular accident in an elderly patient. Five cases (5%) were converted to open surgery. The mean length of stay for the whole group was 4.7 days (range, 2-25). In order to assess the learning curve, procedures were divided into three, equal consecutive groups (n = 33, 33, and 34). Intraoperative complications in the intermediate and late groups were significantly less compared to those in the early group (2/33, 2/34, and 7/33, respectively; (p < 0.05). Similarly, the mean operating time was significantly reduced between the early (169 min) and both intermediate (116 min) and late (127 min) groups (p < 0.005). The conversion rate was reduced between the three groups (3/33, 2/33, and 0/34), but this was not significant (p = 0.06).

CONCLUSIONS

As expected, the outcome of LA is associated with a steep learning curve. According to this study, it seems that performance of approximately 30 cases by an experienced laparoscopic surgeon is required to master the procedure.

Ginseng improves pulmonary functions and exercise capacity in patients with COPD

Ginseng is a root that has been used to treat patients with various illnesses for the last 2000 years. The purpose of this study was to evaluate the effects of Ginseng extract (G115) on Pulmonary Function Tests (PFTs), Maximum Voluntary Ventilation (MVV), Maximum Inspiratory Pressure (MIP) and Maximal Oxygen Consumption (VO2max) in patients with moderately-severe Chronic Obstructive Pulmonary Disease (COPD). Ninety-two adults were randomly divided into the experimental (n = 49, G115 100 mg bid for three months) and placebo-control (n = 43) groups. PFTs, MVV and MIP were studied before treatment and every two weeks for the 3-month-study period. Exercise test and VO2max measurements were performed before the beginning and after six weeks and three months. P lower than 0.05 was considered significant. Baseline demographics and pulmonary parameters were similar between the groups. In the experimental, but not in the control group, all parameters significantly increased above baseline and compared with the placebo group. Maximum increase, compared with baseline was FVC-32.5%, FEV1.0-27.0%, PEF-27.5%, FEF50-45.4%, FEF75-56.9%, MVV-40.4%, MIP-47.0% and VO2max-37.5%. No side effects were observed. G115 100 mg bid for three months, but not placebo, improved PFTs, MVV, MIP and VO2 max in patients with moderately-severe COPD with no side effects.

Cytokine production in Linomide-treated nod mice and the potential role of a Th (1)/Th(2) shift on autoimmune and anti-inflammatory processes

Linomide prevents the development of autoimmune insulitis and insulin-deficient diabetes mellitus in female NOD mice. Linomide prevents development of autoimmune manifestations in other experimentally induced and spontaneous autoimmune diseases as well, but the mechanism of action is unknown. The present report summarizes our investigations on the effect of Linomide on different functional T cell subsets in NOD mice analyzed according to their cytokine profile. Supernatants from cultured splenocytes and peritoneal cells taken from Linomide-treated mice contained lower levels of TNFalpha, IL-1 beta, IFN gamma and IL-12 versus higher levels of IL-4, IL-6 and IL-10 in comparison with supernatants from cultures of untreated mice. Our results suggest that regulation of autoimmunity following oral Linomide administration in NOD mice induces a shift from Th(1) to Th(2) phenotype response, thereby preventing the development of diabetes by active cytokine-induced immunoregulation of T cell subsets, including downregulation of Th(1) and upregulation of Th(2).