A Multi-Agent Architecture for the Design of Hierarchical Interval Type-2 Beta Fuzzy System

This paper presents a new methodology for building and evolving hierarchical fuzzy systems. For the system design, a tree-based encoding method is adopted to hierarchically link low dimensional fuzzy systems. Such tree structural representation has by nature a flexible design offering more adjustable and modifiable structures. The proposed hierarchical structure employs a type-2 beta fuzzy system to cope with the faced uncertainties, and the resulting system is called the Hierarchical Interval Type-2 Beta Fuzzy System (HT2BFS). For the system optimization, two main tasks of structure learning and parameter tuning are applied. The structure learning phase aims to evolve and learn the structures of a population of HT2BFS in a multiobjective context taking into account the optimization of both the accuracy and the interpretability metrics. The parameter tuning phase is applied to refine and adjust the parameters of the system. To accomplish these two tasks in the most optimal and faster way, we further employ a multi-agent architecture to provide both a distributed and a cooperative management of the optimization tasks. Agents are divided into two different types based on their functions: a structure agent and a parameter agent. The main function of the structure agent is to perform a multi-objective evolutionary structure learning step by means of the Multi-Objective Immune Programming algorithm (MOIP). The parameter agents have the function of managing different hierarchical structures simultaneously to refine their parameters by means of the Hybrid Harmony Search algorithm (HHS). In this architecture, agents use cooperation and communication concepts to create high-performance HT2BFSs. The performance of the proposed system is evaluated by several comparisons with various state of art approaches on noise-free and noisy time series prediction data sets and regression problems. The results clearly demonstrate a great improvement in the accuracy rate, the convergence speed and the number of used rules as compared with other existing approaches

Patients with complicated Pott's disease: Management in a rehabilitation department and functional prognosis

AbstractObjectiveThe objective is to study the rehabilitation management and to assess autonomy in daily life activities as well as walking recovery in patients with complicated Pott's disease.Patients and methodsRetrospective study in nine patients over a period of 8 years extending from 2000 to 2008, collated in the Department of Physical Medicine and Functional Rehabilitation, CHU Sahloul, Sousse, Tunisia.ResultsThe mean age of our patients was 43.8 years; sex ratio was 5/4. The spine involvement of tuberculosis was dorsal in seven cases, dorso-lumbar in one patient, and multiple (cervical, dorsal and lumbar) in one case. All patients were paraplegic with a neurological involvement of the bladder. They had prior antituberculosis chemotherapy for at least 8 months. Decompression surgery was performed in six cases. Two female patients presented disorders of spinal posture during treatment requiring surgical revision with osteosynthesis. All patients received additional rehabilitation care. Following a mean duration of hospitalisation in the Rehabilitation department of 47 days with twice-daily sessions of tailored physiotherapy, three patients remained in complete paraplegia, autonomous in wheel-chair and with vesical and sphincter incontinence. The measure of functional independence (MFI) was at admission/discharge 71/92.ConclusionRehabilitation takes an important place in the medico-surgical management in Pott's disease, to limite or compensate the disabilities and handicap related to this pathology

Trans-sinusal frontal approach for olfactory groove meningiomas

Background We report on our experience with the trans-sinusal frontal approach in removing olfactory groove meningiomas in the department of neurosurgery of Univesity Hospital Center of Annaba (Algeria).Methods Ten tumours were operated on by the trans-sinusal frontal approach, using a bicoronal incision, tree tumours developed on one side, and there were seven bilateral olfactosellar tumours. Our procedure : steotomy of the anterior wall of the frontal sinus was performed with an oscillating saw. The posterior wall of the sinus was resected and the tumour was removed through a real subfrontal route along the plane of the anterior skull base. Ethmoidal blood supply was early controlled at the initial stages of the operation, allowing avascular tumour debulking. Tumour extensions toward the sella and the optic canals were removed without brain retraction. Results Seven patients made a good neurologic recovery. Two was dead in the 24 hours after intervention and one four days after. Olfactory nets were preserved on the contralateral side in unilateral tumours. Conclusions The trans-sinusal frontal approach represents an excellent way for tumours developed in the central anterior skull base, especially for olfactory groove meningiomas, whatever their size

Full-length and C-terminal neurogranin in Alzheimer's disease cerebrospinal fluid analyzed by novel ultrasensitive immunoassays

Background: Neurogranin (Ng) is a neuron-specific and postsynaptic protein that is abundantly expressed in the brain, particularly in the dendritic spine of the hippocampus and cerebral cortex. The enzymatic cleavage of Ng produces fragments that are released into cerebrospinal (CSF), which have been shown to be elevated in Alzheimer’s disease (AD) patients and predict cognitive decline. Thus, quantification of distinctive cleavage products of Ng could elucidate different features of the disease. Methods: In this study, we developed novel ultrasensitive single molecule array (Simoa) assays for measurement of full-length neurogranin (FL-Ng) and C-terminal neurogranin (CT-Ng) fragments in CSF. The Ng Simoa assays were evaluated in CSF samples from AD patients (N = 23), mild cognitive impairment due to AD (MCI-AD) (N = 18), and from neurological controls (N = 26). Results: The intra-assay repeatability and inter-assay precision of the novel methods had coefficients of variation below 7% and 14%, respectively. CSF FL-Ng and CSF CT-Ng median concentrations were increased in AD patients (6.02 ng/L, P < 0.00001 and 452 ng/L, P = 0.00001, respectively) and in patients with MCI-AD (5.69 ng/L, P < 0.00001 and 566 ng/L, P < 0.00001) compared to neurological controls (0.644 ng/L and 145 ng/L). The median CSF ratio of CT-Ng/FL-Ng were decreased in AD patients (ratio = 101, P = 0.008) and in patients with MCI-AD (ratio = 115, P = 0.016) compared to neurological controls (ratio = 180). CSF of FL-Ng, CT-Ng, and ratio of CT-Ng/FL-Ng could each significantly differentiate AD patients from controls (FL-Ng, AUC = 0.907; CT-Ng, AUC = 0.913; CT-Ng/FL-Ng, AUC = 0.775) and patients with MCI-AD from controls (FL-Ng, AUC = 0.937; CT-Ng, AUC = 0.963; CT-Ng/FL-Ng, AUC = 0.785). Conclusions: Assessments of the FL-Ng and CT-Ng levels in CSF with the novel sensitive immunoassays provide a high separation of AD from controls, even in early phase of the disease. The novel Ng assays are robust and highly sensitive and may be valuable tools to study synaptic alteration in AD, as well as to monitor the effect on synaptic integrity of novel drug candidates in clinical trials

CSF levels of the BACE1 substrate NRG1 correlate with cognition in Alzheimer’s disease

Background: The presynaptic protein neuregulin1 (NRG1) is cleaved by beta-site APP cleaving enzyme 1 (BACE1) in a similar way as amyloid precursor protein (APP) NRG1 can activate post-synaptic receptor tyrosine-protein kinase erbB4 (ErbB4) and was linked to schizophrenia. The NRG1/ErbB4 complex is neuroprotective, can trigger synaptogenesis and plasticity, increases the expression of NMDA and GABA receptors, and can induce neuroinflammation. This complex can reduce memory formation. In Alzheimer’s disease (AD) brains, NRG1 accumulates in neuritic plaques. It is difficult to determine if NRG1 has beneficial and/or detrimental effects in AD. BACE1 levels are increased in AD brains and cerebrospinal fluid (CSF) and may lead to enhanced NRG1 secretion, but no study has assessed CSF NRG1 levels in AD and mild cognitive impairment (MCI) patients. / Methods: This retrospective study included 162 patients suffering from AD dementia (54), MCI with progression to AD dementia (MCI-AD) (27), non-AD MCI (30), non-AD dementias (30), and neurological controls (27). All patients had neurological examinations, brain MRI, and neuropsychological evaluations. After written informed consent and using enzyme-linked immunosorbent assays (ELISAs), CSF samples were evaluated for Aβ1–42, Aβ1–40, total tau (T-tau), phosphorylated tau on threonine 181 (P-tau), BACE1, growth-associated protein 43 (GAP 43), neurogranin (Ng), and NRG1. / Results: Levels of NRG1 were significantly increased in the CSF of AD (+ 36%) and MCI-AD (+ 28%) patients compared to neurological controls and also non-AD MCI and non-AD dementias. In addition, in AD and MCI-AD patients, NRG1 levels positively correlated with Aβ1–42 but not with T-tau, P-tau, and BACE1 levels and negatively correlated with MMSE scores. A longitudinal follow-up study of AD patients revealed a trend (p = 0.08) between CSF NRG1 levels and cognitive decline. In the overall population, NRG1 correlated with MMSE and the synaptic biomarkers GAP 43 and neurogranin. / Conclusions: Our results showed that CSF NRG1 levels are increased in AD and MCI-AD as compared to controls and other dementias. CSF NRG1 levels are associated with cognitive evolution, and a major outcome of our findings is that synaptic NRG1 could be involved in the pathophysiology of AD. Modulating brain NRG1 activity may represent a new therapeutic target in AD

Quantum Gravitational Corrections to the Real Klein-Gordon Field in the Presence of a Minimal Length

The (D+1)-dimensional $(\beta,\beta')$-two-parameter Lorentz-covariant deformed algebra introduced by Quesne and Tkachuk [C. Quesne and V. M. Tkachuk, J. Phys. A: Math. Gen. \textbf {39}, 10909 (2006).], leads to a nonzero minimal uncertainty in position (minimal length). The Klein-Gordon equation in a (3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant deformed algebra is studied in the case where $\beta'=2\beta$ up to first order over deformation parameter $\beta$. It is shown that the modified Klein-Gordon equation which contains fourth-order derivative of the wave function describes two massive particles with different masses. We have shown that physically acceptable mass states can only exist for $\beta<\frac{1}{8m^{2}c^{2}}$ which leads to an isotropic minimal length in the interval $10^{-17}m<(\bigtriangleup X^{i})_{0}<10^{-15}m$. Finally, we have shown that the above estimation of minimal length is in good agreement with the results obtained in previous investigations.Comment: 10 pages, no figur

Influence of severe plastic deformation on the precipitation hardening of a FeSiTi steel

The combined strengthening effects of grain refinement and high precipitated volume fraction (~6at.%) on the mechanical properties of FeSiTi alloy subjected to SPD processing prior to aging treatment were investigated by atom probe tomography and scanning transmission electron microscopy. It was shown that the refinement of the microstructure affects the precipitation kinetics and the spatial distribution of the secondary hardening intermetallic phase, which was observed to nucleate heterogeneously on dislocations and sub-grain boundaries. It was revealed that alloys successively subjected to these two strengthening mechanisms exhibit a lower increase in mechanical strength than a simple estimation based on the summation of the two individual strengthening mechanisms