Guidelines for Weighting Factors Adjustment in Finite State Model Predictive Control of Power Converters and Drives

INTERNATIONAL CONFERENCE ON INDUSTRIAL TECHNOLOGY () (.2009.VICTORIA, AUSTRALIA)Model Predictive Control with a finite control set has emerged as a promising control tool for power converters and drives. One of the major advantages is the possibility to control several system variables with a single control law, by including them with appropriate weighting factors. However, at the present state of the art, these coefficients are determined empirically. There is no analytical or numerical method proposed yet to obtain an optimal solution. In addition, the empirical method is not always straightforward, and no procedures have been reported. This paper presents a first approach to a set of guidelines that reduce the uncertainty of this process. First a classification of different types of cost functions and weighting factors is presented. Then the different steps of the empirical process are explained. Finally, results for several power converters and drives applications are analyzed, which show the effectiveness of the proposed guidelines to reach appropriate weighting factors and control performance

Impaired release of Vitamin D in dysfunctional adipose tissue: New cues on Vitamin D supplementation in obesity

Context: Vitamin D accumulates in adipose tissue (AT) and vitamin D deficiency is frequent in obesity. Objective: We hypothesize that trafficking of vitamin D is altered in dysfunctional AT. Design, Patients, Settings: 54 normal-weight and 67 obese males were recruited in a prospective study and randomly assigned to supplementation with 50 \ub5g/week 25-hydroxyvitamin-D3 (25(OH)D) or 150 \ub5g/week vitamin D3 for 1 year, raising dosage by 50% if vitamin D-sufficiency (serum 25(OH)D>50 nomol/l), was not achieved at 6 months; 97 subjects completed the study. Methods: Vitamin D3 (D3) and 25(OH)D were quantified by HPLC-MS in control and insulin-resistant (IR) 3T3-L1 cells and subcutaneous AT (SAT) from lean and obese subjects, incubated with or without adrenaline; expression of 25-hydroxylase (CYP27A1), 1\u3b1-hydroxylase (CYP27B1) and vitamin D receptor (VDR) were analysed by real-time PCR. Results: In IR adipocytes the uptake of D3 and 25(OH)D was higher, but after adrenaline stimulation, the decrement in D3 and 25(OH)D was stronger in control cells, which also showed increased expression of CYP27A1 and CYP27B1 and higher levels of 25(OH)D. In SAT from obese subjects, the adrenaline-induced release of D3 and 25(OH)D was blunted; in both IR cells and obese SAT, protein expression of \u3b22-adrenergic receptor was reduced. Supplementation with 25-hydroxyvitamin-D3 was more effective in achieving vitamin D sufficiency in obese, but not in normal weight subjects. Conclusion: Dysfunctional AT shows a reduced catecholamine-induced release of D3 and 25(OH)D, and altered activity of vitamin D-metabolizing enzymes, for these reasons supplementation with 25-hydroxyvitamin-D3 is more effective in obese individuals

Disordered Rock-Salt Type Li2TiS3 as Novel Cathode for LIBs: A Computational Point of View

The development of high-energy cathode materials for lithium-ion batteries with low content of critical raw materials, such as cobalt and nickel, plays a key role in the progress of lithium-ion batteries technology. In recent works, a novel and promising family of lithium-rich sulfides has received attention. Among the possible structures and arrangement, cubic disordered Li(2)TiS(3) has shown interesting properties, also for the formulation of new cell for all-solid-state batteries. In this work, a computational approach based on DFT hybrid Hamiltonian, localized basis functions and the use of the periodic CRYSTAL code, has been set up. The main goal of the present study is to determine accurate structural, electronic, and spectroscopic properties for this class of materials. Li(2)TiS(3) precursors as Li(2)S, TiS(2), and TiS(3) alongside other formulations and structures such as LiTiS(2) and monoclinic Li(2)TiS(3) have been selected as benchmark systems and used to build up a consistent and robust predictive scheme. Raman spectra, XRD patterns, electronic band structures, and density of states have been simulated and compared to available literature data. Disordered rock-salt type Li(2)TiS(3) structures have been derived via a solid solution method as implemented into the CRYSTAL code. Representative structures were extensively characterized through the calculations of their electronic and vibrational properties. Furthermore, the correlation between structure and Raman fingerprint was established

Voxelwise assessment of the regional distribution of damage in the brains of patients with multiple sclerosis and fatigue

BACKGROUND AND PURPOSE: Fatigue affects up to 90% of patients with MS. We assessed the regional distribution of lesions and atrophy of the normal-appearing WM and GM in patients with RRMS with fatigue compared with HC and patients with similar characteristics, but without fatigue. MATERIALS AND METHODS: From 14 patients with RRMS without fatigue, 10 with RRMS with fatigue, and 14 HC, we acquired brain dual-echo and high-resolution T1-weighted scans. Voxel-wise distributions of GM, WM damage, and T2 lesions were compared between patients with fatigued and nonfatigued MS by using SPM5 software. We report results at P < .05, FWE corrected. RESULTS: T2 lesion distribution and regional WM atrophy did not differ between patients with fatigued and nonfatigued MS. Compared with HC, patients with MS had significant WM atrophy in the posterior part of the corpus callosum and significant GM atrophy of the left superior frontal sulcus, left precentral gyrus, posterior cingulate cortex, right thalamus, and left middle frontal gyrus. No additional areas of atrophy were found in patients with nonfatigued MS compared with HC, whereas patients with fatigued MS also had atrophy of the left central sulcus. Atrophy in the left central sulcus and the precentral gyrus was more severe in patients with fatigued versus nonfatigued MS. In patients with MS, significant correlations were found between fatigue severity and GM atrophy in the left precentral gyrus (r = −0.73, P < .0001 uncorrected). CONCLUSIONS: Atrophy of the primary sensorimotor area is likely to contribute to MS-related fatigue

Effectiveness of endoscopic trans-tendineous repair for partial-thickness tears of medius gluteus: A systematic review of literature

Tears of the gluteus medius can result in chronic hip pain over time. Pathological onsets involving the gluteus medius cause pain and weakness of abductor strength. Endoscopic repair is a suitable, effective and safe surgical alternative to traditional open techniques and give satisfactory results over time restoring the footprint of gluteus medius. The purpose of this systematic review is to analyse the effectiveness of endoscopic trans-tendinous technique for partial-thickness tears, analysing the subjective and functional outcome over the time. A search of literature (PubMed, Scopus, WebOfKnowledge) was performed. The PRISMA method was used to screen the articles. A total of 4 articles was screened and included for qualitative analysis. For data extraction patient characteristics, pre-clinical examination, imaging, timing from symptoms to surgery, technique performed, subjective scales, functional outcomes, post-operative clinical assessment were analysed. Subjective scores at mean follow-up of 18 months show a significative improvement in all the scales reported, in relief of pain (VAS score) and in terms of strength of abductor. Trans-tendinous technique represents the gold standard to treat endoscopically these injuries. Furthermore, other studies with larger number of patients and longer follow-up are required to validate the best surgical approach for these injuries

Kinetic analysis of secondary precipitation in a HP40-Nb alloy

The HP40-Nb heat resistant alloy (35Ni-25Cr-Nb) was analysed by means of optical microscopy after aging treatments at 1073 and 1173 K for different times, in order to apply the classic Johnson – Mehl-Avrami – Kolmogorov kinetic model (JMAK), and thus calculate the activation energy of secondary M23C6 precipitation, which occurs during thermal aging. The relevance of this theoretical analysis is to infer the mechanism that controls the nucleation and growth of M23C6 secondary carbides, since the amount and morphology of these phase influences the mechanical properties as well as the corrosion resistance in service. After performing the kinetic analysis using the JMAK model, the activation energy was found to be 208 kJ/mol, which would indicate that the secondary precipitation in this alloy is controlled by the Cr-diffusion phenomenon along the austenitic matrix.Fil: Sosa Lissarrague, Matías Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería. Laboratorio de Metalurgia y Tecnología Mecánica; ArgentinaFil: Juan, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; ArgentinaFil: Lanz, César Armando. Universidad Nacional del Sur. Departamento de Ingeniería. Laboratorio de Metalurgia y Tecnología Mecánica; ArgentinaFil: La Rocca, Bruno. Consejo Interuniversitario Nacional. - Ministerio de Educación, Cultura, Ciencia y Tecnología. Consejo Interuniversitario Nacional; ArgentinaFil: Picasso, Alberto Carlos. Universidad Nacional del Sur. Departamento de Ingeniería. Laboratorio de Metalurgia y Tecnología Mecánica; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentin

Evidence for Cortical Functional Changes in Patients With Migraine and White Matter Abnormalities on Conventional and Diffusion Tensor Magnetic Resonance Imaging

Background— In this study, we used functional MRI (fMRI) to investigate the pattern of cortical activations after a simple motor task in patients with migraine and white matter (WM) abnormalities on conventional MRI scans of the brain. We also investigated whether the extent of brain activations was correlated with WM structural pathology measured using diffusion tensor (DT) MRI. Methods— From 15 right-handed patients with migraine and 15 sex- and age-matched, right-handed healthy volunteers, we obtained the following: (1) fMRI (repetitive flexion-extension of the last 4 fingers of the right hand), (2) dual-echo turbo spin echo scans, and (3) pulsed-gradient spin-echo echo-planar sequence to calculate DT-MRI maps. fMRI analysis was performed using SPM99 and cluster detection. We measured the volume, the average mean diffusivity ( ), and the average fractional anisotropy of all lesions seen on the dual-echo scans. histograms of the normal-appearing WM were also produced. Results— Compared with healthy volunteers, migraine patients had a larger relative activation of the contralateral primary sensorimotor cortex ( P =0.01) and a rostral displacement of the supplementary motor area ( P =0.03). The shapes of the curves reflecting the time course for fMRI signal intensity changes were similar between migraine patients and controls for all of the cortical areas we studied. Compared with healthy subjects, migraine patients had significantly lower histogram peak height of the normal-appearing WM histogram ( P =0.02), which was found to be correlated with the extent of displacement of the supplementary motor area ( r =−0.80, P <0.001). Conclusions— This study suggests that functional cortical changes occur in patients with migraine and brain MRI abnormalities and that they might be secondary to the extent of subcortical structural damage

Brain Gray Matter Changes in Migraine Patients With T2-Visible Lesions

Background and Purpose— In migraine patients, functional imaging studies have shown changes in several brain gray matter (GM) regions. However, 1.5-T MRI has failed to detect any structural abnormality of these regions. We used a 3-T MRI scanner and voxel-based morphometry (VBM) to assess whether GM density abnormalities can be seen in patients with migraine with T2-visible abnormalities and to grade their extent. Methods— In 16 migraine patients with T2-visible abnormalities and 15 matched controls, we acquired a T2-weighted and a high-resolution T1-weighted sequence. Lesion loads were measured on T2-weighted images. An optimized version of VBM analysis was used to assess regional differences in GM densities on T1-weighted scans of patients versus controls. Statistical parametric maps were thresholded at P <0.001, uncorrected for multiple comparisons. Results— Compared with controls, migraine patients had areas of reduced GM density, mainly located in the frontal and temporal lobes. Conversely, patients showed increased periacqueductal GM (PAG) density. Compared with patients without aura, migraine patients with aura had increased density of the PAG and of the dorsolateral pons. In migraine patients, reduced GM density was strongly related to age, disease duration, and T2-visible lesion load ( r ranging from −0.84 to −0.73). Conclusions— Structural GM abnormalities can be detected in migraine patients with brain T2-visible lesions using VBM and a high-field MRI scanner. Such GM changes comprise areas with reduced and increased density and are likely related to the pathological substrates associated with this disease

Laparoscopic single site (LESS) and classic video-laparoscopic cholecystectomy in the elderly: A single centre experience

Laparoscopic cholecystectomy (LC) is the gold-standard surgical method used to treat gallbladder diseases. Recently Laparoendoscopic single site surgery (LESS) has gained greater interest and diffusion for the surgical treatment of several pathologies. In elderly patients, just few randomized controlled trials are present in the literature that confirm the clinical advantages of LESS compared with the classic laparoscopic procedures.We present in this paper the preliminary results of this randomized prospective study regarding the feasibility and safety of LESS cholecystectomy versus classic laparoscopic technique. We demonstrated that LESS technique compared with traditional technique show some advantages like: acceptable operative times, lower post-operative discomfort and sometimes reduction added complications. In addition we also demonstrate that fewer incisions and less scarring which mean less pain, and fewer parietal complications are related to this surgical procedure. In conclusion in the elderly LESS cholecystectomy technique is to be considered a suitable alternative to traditional three-port cholecystectomy