Identification of DC thermal steady-state differential inductance of ferrite power inductors

In this paper, we propose a method for the identification of the differential inductance of saturable ferrite inductors adopted in DC–DC converters, considering the influence of the operating temperature. The inductor temperature rise is caused mainly by its losses, neglecting the heating contribution by the other components forming the converter layout. When the ohmic losses caused by the average current represent the principal portion of the inductor power losses, the steady-state temperature of the component can be related to the average current value. Under this assumption, usual for saturable inductors in DC–DC converters, the presented experimental setup and characterization method allow identifying a DC thermal steady-state differential inductance profile of a ferrite inductor. The curve is obtained from experimental measurements of the inductor voltage and current waveforms, at different average current values, that lead the component to operate from the linear region of the magnetization curve up to the saturation. The obtained inductance profile can be adopted to simulate the current waveform of a saturable inductor in a DC–DC converter, providing accurate results under a wide range of switching frequency, input voltage, duty cycle, and out-put current values

Data-Driven Constraint Handling in Multi-Objective Inductor Design

This paper analyses the multi-objective design of an inductor for a DC-DC buck converter. The core volume and total losses are the two competing objectives, which should be minimised while satisfying the design constraints on the required differential inductance profile and the maximum overheating. The multi-objective optimisation problem is solved by means of a population-based metaheuristic algorithm based on Artificial Immune Systems (AIS). Despite its effectiveness in finding the Pareto front, the algorithm requires the evaluation of many candidate solutions before converging. In the case of the inductor design problem, the evaluation of a configuration is time-consuming. In fact, a non-linear iterative technique (fixed point) is needed to obtain the differential inductance profile of the configuration, as it may operate in conditions of partial saturation. However, many configurations evaluated during an optimisation do not comply with the design constraint, resulting in expensive and unnecessary calculations. Therefore, this paper proposes the adoption of a data-driven surrogate model in a pre-selection phase of the optimisation. The adopted model should classify newly generated configurations as compliant or not with the design constraint. Configurations classified as unfeasible are disregarded, thus avoiding the computational burden of their complete evaluation. Interesting results have been obtained, both in terms of avoided configuration evaluations and the quality of the Pareto front found by the optimisation procedure

Adjuvant benefit of a peptide-rich marine biology formula (LD-1227) in rheumatoid arthritis: a randomized, double-blind, controlled study

Introduction. There is a growing interest on non-chemical therapies among patients suffering from rheumatoid arthritis (RA), although safety, efficacy and properly designed studies are often lacking. Objective. The aim of the present investigation was to explore the clinical effectiveness of a marine nutraceutical, LD-1227, endowed by fine molecular biology studies, in the management of RA. Methods. The study design was a 12-week, randomized, double-blind study involving forty patients with stable longstanding RA who were randomized to receive either LD-1227 (n = 20) or Omega-3 (n = 20) on top of their established maintenance therapy. Results. At study recruitment and after 12 weeks of treatment, their Health Assessment Questionnaire (HAQ), erythrocyte sedimentation rate (ESR), visual analogue scale (VAS), and Disease Activity Score (DAS) 28, anxiety and depression analysis, C-reactive protein (CRP) levels, CXCL1, several pro-inflammatory interleukins levels and related gene expression, were compared between the two groups. Primary end point was the proportion of patients with response at weeks 12 as from the 20 % to 50% improvement criteria of the American College of Rheumatology (ACR20). At 12 weeks, ACR20 beneficial response was 81.0 % in LD-1227 group and 44 % in omega-3 group, (p< 0.01). The superiority of LD-1227 appeared also when considering the ACR50 response at 12 weeks (62% in LD-1227 group as compared to 31 % in omega-3 group, p< 0.01). The LD-1227-treated group displayed a significant improvement of VAS scale, HAQ score, morning stiffness and tender points (p < 0.01 vs control and p < 0.05 vs omega-3, respectively). From the biochemical viewpoint, patients in the LD-1227 group showed a lower level of CRP, IL-6, TNF-α, IL-1β, CXCL1, IFNγ, IL-15 and IP-10 and significant downregulation of related gene expressions. Unlike what observed in LD-1227 group, in the omega-3 group, CRP and DAS28 did not reach statistical difference. A substantial reduction of extra pain killer use was noted under LD-1227 treatment. Conclusion. One can conclude that LD-1227 may play a significant role on the management of RA and with a specrum and mechanisms of actions distinct from the canonical omega-3 while being devoid of any side effect or tolerability issues

A randomized, controlled trial on the effectiveness of a proprietary marine lipo-peptide formula vs omega-3 on cytokines profile, anxiety, and pain symptoms in patients with fibromyalgia

Objective: The aim of the present study in an RCT manner (physicians and patients) a novel lipo-peptide marine compound, LD-1227, on physical-, emotional- and functional-related symptomatic complaints in fibromyalgia patients as well as inflammatory cytokines profile and gene expression while using omega-3 as a control group. Methods: The following questionnaire-based or clinical evaluation-based parameters were evaluated: widespread pain index [WPI] patient global impression of change, total tender points [TTP], fibromyalgia impact questionnaire, Beck depression inventory, fatigue severity ratings, cognitive symptom severity, symptom severity score [SSS] and weekly pain intensity ratings. Additional biochemical and gene expression analysis of cytokines (IL6, TNF-α, IL-1β, MCP-1, IL-8, IL-13, IL-1α, and GM-CSF) was performed as well. Data were analyzed with either a paired t-test or the Wilcoxon signed rank test depending on the parametric or non-parametric distribution. Results: Comparing the data from before and after treatment for Group B indicated a statistically significant reduction (p=0.05) in TTP, WPI score, and SSS score. These data suggest a positive effect of a 3-month treatment with the LD-1227 but not omega-3 treatment on Fibromyalgia pain and related anxiety/depressive symptoms. Inspections of HRV and Cytokines found a statistically significant improvement after LD1227 treatment. Unlike the group supplemented with omega-3, the treatment with LD-1227 brought about a decrease in WPI and weekly pain intensity symptoms for the majority of participants. The pre-and post-treatment data for Group B indicated a statistically significant reduction (p=0.05) in TPC, WPI, and SSS scores. No adverse events were reported. Conclusion: These results provide the first indications that the LD-1227 treatment has a statistically significant effect on the recognized fibromyalgia diagnosis metrics of WPI, TTP, and SSS as well on inflammatory markers and parasympathetic balance

Effect of Celergen, a marine derivative, on in vitro hepatocarcinogenesis

The aim of this study was to test for a potential anticarcinogenic effect of Celergen, a marine derivative devoid of traceable amounts of inorganic arsenic, on cell proliferation, cell cycle progression and apoptosis in the HepG2 human liver cancer cell line. Celergen significantly inhibited the proliferation of cancer cells in a dose-dependent manner while limiting the cell cycle progression at the G1 phase and significantly inducing apoptosis. Further examination showed that Celergen enhanced expression of the p21CIPl1WAF1, GADD153 genes and downregulated the c-myc gene. These results suggest that Celergen exerts promising chemopreventive properties to be further investigated

MISA [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201