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This paper proposes a multi-objective H2/H ∞ maximum power tracking control of a variable speed wind turbine to minimize the H2 tracking error and ensure the H ∞ model reference-tracking performance, simultaneously. The optimal condition is obtained via a boost converter use, which adapts the load impedance to the wind turbine generator. Thus, based on the fuzzy T-S model, a multi-objective Maximum Power Point Tracking (MPPT) controller is developed, ensuring maximum power transfer, despite wind speed variation and system uncertainty. To specify the optimal trajectory to follow, a TS reference model is proposed taking as input the optimal rectified DC current. The conditions of stability and stabilization are expressed in terms of linear matrix inequality (LMI) for uncertain and disturbed T-S models leading to determining the controller gains. Finally, an example of MPP tracking applied to a Wind Energy Conversion System (WECS) illustrates the effectiveness of the proposed fuzzy control law. [ABSTRACT FROM AUTHOR]

This paper presents a combination between a fuzzy logic control (FLC) and a predictive direct power control for multifunctional grid connected photovoltaic (PV) system, to solve the oscillation problem in the DC link voltage of the inverter caused by the fast irradiation changing. The whole system consists of a PV system which interface a DC-AC inverter, a FLC maximum power point tracking (MPPT) algorithm has been adopted to operate the DC-DC converter at the MPP. The predictive control strategy is applied to the DC-AC inverter with FLC in its voltage control loop to improve the power exchange between the grid and the PV system. Simulation results have been verified through MATLAB/Simulink software for the purpose of giving the effectiveness of the suggested control against existed controllers. [ABSTRACT FROM AUTHOR]

Desmoid tumors (DT) are rare benign tumors with a local invasion potential and recurrence. It is characterized on histology by an abnormal fibroblastic proliferation in a collagenous stroma, in variable proportions leading to heterogeneity of the lesion signal on magnetic resonance imaging (MRI). Current guidelines propose watchful waiting but in case of progression or symptoms, cryotherapy may be a therapeutic option in its extra-abdominal form. Tumor recurrence is mostly detected based on post-contrast magnetic resonance imaging (MRI). Although DWI sequence is the key-sequence for tumor detection in oncologic imaging, there are very few data in literature on diffusion weighted imaging (DWI) in DT generally and even fewer on DT after cryotherapy. DWI changes after cryotherapy may be confusing and suspicious of residual tumor or tumor recurrence when displaying low ADC values; thus knowledge of possible DWI patterns after cryotherapy of DT seem paramount. We found that the early changes of DT after cryotherapy are hyperintensity on DWI sequence with low ADC values (<1.00 × 10−3mm2/s), without corresponding enhancement and a later decrease in signal of the treated lesion on DWI. The freezing-thawing cycles of cryotherapy turn DT into gelatinous necrosis with a slow resorption rate, as reported in the only few studies referring of changes of DWI signals after cryotherapy, which are on renal and prostate models. Hyperintensity on DWI with low ADC values may be seen in early MRI follow-up after cryotherapy of extra-abdominal DT, corresponding with tumor necrosis changes and should not be mistaken with recurrence. Magnetic resonance imaging is the modality of choice for desmoid tumor (DT) follow-up, mainly based on contrast uptake which make data on diffusion weighted imaging (DWI) very rare. Cryotherapy is an accepted therapeutic option for DT that will lead to tumor necrosis. Hyperintensity on DWI with low apparent diffusion coefficient values is a possible expected early pattern on DWI after cryotherapy of DT. [ABSTRACT FROM AUTHOR]

Introduction: Chronic lung allograft dysfunction (CLAD) can take two forms: bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). The aim was to determine if chest-CT abnormalities after lung transplantation (LTx) could predict CLAD before respiratory functional deterioration. Materials and methods: This monocentric retrospective study analyzed consecutive patients who underwent LTx from January 2015 to December 2018. Initial CT post-LTx (CTi) and a follow-up CT at least 9 months post-LTx (CTf) were reviewed. CLAD was defined as a persistent respiratory functional decline (> 20% of basal FEV1) outside acute episode. A Cox regression was performed in univariate, then in multivariate analysis (including features with p < 0.01 in univariate or of clinical importance) to determine risk factors for CLAD. Subgroup analyses were made for BOS, RAS, and death. Results: Among 118 LTx patients (median (min–max) 47 (18–68) years), 25 developed CLAD during follow-up (19 BOS). The median time to CLAD since LTx was 570 days [150–1770]. Moderate pulmonary artery stenosis (30–50%) was associated with the occurrence of CLAD on CTi (hazard ratio HR = 4.6, CI [1.6–13.2]) and consolidations and pleural effusion on CTf (HR = 2.6, CI [1.3–4.9] and HR = 4.5, CI [1.5–13.6] respectively). The presence of mosaic attenuation (HR = 4.1, CI [1.4–12.5]), consolidations (HR = 2.6, CI [1.3–5.4]), and pleural effusions (p = 0.01, HR = 5.7, CI [1.4–22.3]) were risk factors for BOS on CTf. The consolidations (p = 0.029) and pleural effusions (p = 0.001) were risk factors for death on CTf. Conclusions: CTi and CTf in the monitoring of LTx patients could predict CLAD. Moderate pulmonary artery stenosis, mosaic pattern, parenchyma condensations, and pleural effusions were risk factors for CLAD. Critical relevance statement: There is a potential predictive role of chest CT in the follow-up of LTx patients for chronic lung allograft dysfunction (CLAD). Early chest CT should focus on pulmonary artery stenosis (risk factor for CLAD in this study). During the follow-up (at least 9 months post-LTx), parenchymal consolidations and pleural effusions were shown to be risk factors for CLAD, and death in subgroup analyses. Key points: • Pulmonary artery stenosis (30–50%) on initial chest-CT following lung transplantation predicts CLAD HR = 4.5; CI [1.6–13.2]. • Pleural effusion and consolidations 1 year after lung transplantation predict CLAD and death. • Early evaluation of lung transplanted patients should evaluate pulmonary artery anastomosis. [ABSTRACT FROM AUTHOR]

Objectives: Lung carcinoids and atypical hamartomas may be difficult to differentiate but require different treatment. The aim was to differentiate these tumors using contrast-enhanced CT semantic and radiomics criteria. Methods: Between November 2009 and June 2020, consecutives patient operated for hamartomas or carcinoids with contrast-enhanced chest-CT were retrospectively reviewed. Semantic criteria were recorded and radiomics features were extracted from 3D segmentations using Pyradiomics. Reproducible and non-redundant radiomics features were used to training a random forest algorithm with cross-validation. A validation-set from another institution was used to evaluate of the radiomics signature, the 3D 'median' attenuation feature (3D-median) alone and the mean value from 2D-ROIs. Results: Seventy-three patients (median 58 years [43‒70]) were analyzed (16 hamartomas; 57 carcinoids). The radiomics signature predicted hamartomas vs carcinoids on the external dataset (22 hamartomas; 32 carcinoids) with an AUC = 0.76. The 3D-median was the most important in the model. Density thresholds < 10 HU to predict hamartoma and > 60 HU to predict carcinoids were chosen for their high specificity > 0.90. On the external dataset, sensitivity and specificity of the 3D-median and 2D-ROIs were, respectively, 0.23, 1.00 and 0.13, 1.00 < 10 HU; 0.63, 0.95 and 0.69, 0.91 > 60 HU. The 3D-median was more reproducible than 2D-ROIs (ICC = 0.97 95% CI [0.95‒0.99]; bias: 3 ± 7 HU limits of agreement (LoA) [− 10‒16] vs. ICC = 0.90 95% CI [0.85‒0.94]; bias: − 0.7 ± 21 HU LoA [− 4‒40], respectively). Conclusions: A radiomics signature can distinguish hamartomas from carcinoids with an AUC = 0.76. Median density < 10 HU and > 60 HU on 3D or 2D-ROIs may be useful in clinical practice to diagnose these tumors with confidence, but 3D is more reproducible. Critical relevance statement: Radiomic features help to identify the most discriminating imaging signs using random forest. 'Median' attenuation value (Hounsfield units), extracted from 3D-segmentations on contrast-enhanced chest-CTs, could distinguish carcinoids from atypical hamartomas (AUC = 0.85), was reproducible (ICC = 0.97), and generalized to an external dataset. Key points: • 3D-'Median' was the best feature to differentiate carcinoids from atypical hamartomas (AUC = 0.85). • 3D-'Median' feature is reproducible (ICC = 0.97) and was generalized to an external dataset. • Radiomics signature from 3D-segmentations differentiated carcinoids from atypical hamartomas with an AUC = 0.76. • 2D-ROI value reached similar performance to 3D-'median' but was less reproducible (ICC = 0.90). [ABSTRACT FROM AUTHOR]

Immunoglobulin G4‐related disease (IgG4‐RD) is a recently described rare systemic fibroinflammatory disease with an estimated incidence of less than 1 in 100,000 persons per year. The disease can affect virtually any organ and is characterized by unifying histopathological findings. Recently, four subgroups of patients have been characterized: hepatobiliary, head and neck, Mikulicz syndrome and retroperitoneal fibrosis, who illustrate the mainly abdominal and ENT tropism of the disease. Yet, thoracic involvement is not uncommon. It can be detected in up to 30% of patients with systemic IgG4‐RD and is the exclusive manifestation of the disease in about 10% of cases. Clinical symptoms are nonspecific and may include dyspnoea, cough or chest pain. Chest CT findings are heterogeneous and primarily include peribronchovascular thickening, nodules, ground‐glass opacities and lymphadenopathy. There is no specific diagnostic test for IgG4‐RD thoracic involvement, which may mimic malignancy or vasculitis. Therefore, a cautious approach is needed to make an accurate diagnosis: a search for extra‐thoracic manifestations, elevated serum IgG4 levels, circulating levels of plasmablasts and pathologic evidence of disease is warranted. Although very suggestive, neither the presence of a polyclonal IgG4 lymphoplasmacytic infiltrate, storiform fibrosis or obliterative phlebitis are sufficient to confirm the histological diagnosis. Steroids are recommended as first‐line therapy. Rituximab or disease‐modifying antirheumatic drugs may be used in relapsed or rare cases of steroid‐refractory disease. In this review, we summarize current knowledge regarding the pathophysiology, epidemiology, diagnostic modalities (clinical–biological–imaging–histopathology) and treatment of IgG4‐RD thoracic involvement. [ABSTRACT FROM AUTHOR]

The correction notice for the article "Prevalence and risk factors for lung involvement on low-dose chest CT (LDCT) in a paucisymptomatic population of 247 patients affected by COVID-19" clarifies that the study was actually retrospective, not prospective as originally stated. The investigation confirmed the retrospective nature of the study based on a research protocol provided, which matched the reported work conducted between March and June 2020. The references to the study as prospective have been corrected, and the original article has been updated accordingly. [Extracted from the article]

Background: After stereotactic body radiation therapy (SBRT) for lung tumors, follow-up CT scans remain a pitfall. The early detection of local relapse is essential to propose a new treatment. We aim to create a local recurrence predictive score using pre- and post-therapeutic imaging criteria and test it on a validation cohort. Methods: Between February 2011 and July 2016, lung tumors treated by SBRT with available pretreatment fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) and follow-up CT scans were retrospectively analyzed. The risk factors associated with relapse were identified by univariate logistic regression on a train cohort. The score was created using these factors, merging clinical and imaging criteria associated with local relapse, and then tested on an independent validation cohort. Overall and local relapse-free survival at 1 and 3 years were recorded. Results: Twenty-eight patients were included in the train cohort and ten in the derivation cohort (male 74%, median age 70 ± 12 years). Five variables significantly associated with local recurrence (female gender; sequential enlargement; craniocaudal growing; bulging margins; standardized uptake value (SUVmax > 5.5)) were combined to create the score on five points. With the threshold >2.5/5, the sensitivity and specificity of the score on the validation cohort were 100% and 88%, respectively. Overall survival and local relapse-free survival at 1 and 3 years were 89% and 42%, and 89% and 63%, respectively. Conclusion: The local recurrence risk score created has high sensitivity (100%) and specificity (88%), upon independent validation cohort, to detect local relapse. This score is easy to use in daily clinical practice. [ABSTRACT FROM AUTHOR]

This CIRSE Standards of Practice document is aimed at interventional radiologists and provides best practices for performing bronchial artery embolisation to effectively treat haemoptysis. It has been developed by an expert writing group established by the CIRSE Standards of Practice Committee. [ABSTRACT FROM AUTHOR]

Pulmonary involvement of IgG4‐associated disease is a rare condition with no codified treatment apart from steroid administration. We report here the case of a patient with pulmonary involvement of IgG4‐RD successfully managed with Rituximab, in induction and maintenance therapy. This original case could support the use of Rituximab in rare situations of steroid‐resistant or steroid‐dependent pulmonary IgG4‐RD. [ABSTRACT FROM AUTHOR]

Objective Immunoglobulin G4-related disease (IgG4-RD) is a rare orphan disease. Lung, pleura, pericardium, mediastinum, aorta and lymph node involvement has been reported with variable frequency and mostly in Asian studies. The objective of this study was to describe thoracic involvement assessed by high-resolution thoracic computed tomography (CT) in Caucasian patients with IgG4-RD. Methods Thoracic CT scans before treatment were retrospectively collected through the French case registry of IgG4-RD and a single tertiary referral centre. CT scans were reviewed by two experts in thoracic imagery blinded from clinical data. Results 48 IgG4-RD patients with thoracic involvement were analysed. All had American College of Rheumatology/European League Against Rheumatism classification scores -20 and comprehensive diagnostic criteria for IgG4-RD. CT scan findings showed heterogeneous lesions. Seven patterns were observed: peribronchovascular involvement (56%), lymph node enlargement (31%), nodular disease (25%), interstitial disease (25%), ground-glass opacities (10%), pleural disease (8%) and retromediastinal fibrosis (4%). In 37% of cases two or more patterns were associated. Asthma was significantly associated with peribronchovascular involvement (p=0.04). Among eight patients evaluated by CT scan before and after treatments, only two patients with interstitial disease displayed no improvement. Conclusion Thoracic involvement of IgG4-RD is heterogeneous and likely underestimated. The main thoracic CT scan patterns are peribronchovascular thickening and thoracic lymph nodes. [ABSTRACT FROM AUTHOR]

This paper discusses a renewable energy system connected to a dual-function power grid through a shunt active power filter to improve the power quality and inject photovoltaic (PV) energy to the power grid in the presence of nonlinear loads. Disturbance rejection for this electrical network is provided by the proposed direct power control (DPC) command. The DPC strategy combines a fractional order PID controller for the regulation of the DC bus voltage with an intelligent method of tracking the maximum power point articulated on the fuzzy logic, reserved to address dynamic weather conditions. The quality of energy is offered by the improved DPC resides in the elimination of the undesirable harmonics of the source currents. Thus, the studied system operates under a power factor near unity with acceptable harmonic distortion, in agreement with the international standard IEEE-519. The overall control of the presented system is assessed under different states of the power source behavior—balanced, unbalanced, and distorted—through simulation using MATLAB/Simulink software. The results demonstrate the performance, robustness, and feasibility of the proposed methods compared to the existing techniques in the literature. [ABSTRACT FROM AUTHOR]

A novel nonlinear maximum power point tracking (MPPT) controller for autonomous photovoltaic systems based on synergetic control theory is presented in this paper as a solution to eliminate the chattering drawback provided by sliding mode controller, where the proposed strategy allows to generate continuous control law instead of a switching term. A DC/DC boost converter is introduced in the content of this work as an interface between a photovoltaic array and a resistive load. The developed MPPT controller was tested both in simulations using Matlab/Simulink tool and experimentally using dSPACE RTI 1104 real‐time platform and compared with the sliding mode‐based MPPT controller. Furthermore, the EN 50530 standard test with different ramp gradients values is used to calculate the MPPT efficiency under irradiance changes from the slow to the very fast. Illustrative results that prove the effectiveness and the robustness of the proposed MPPT controller even the non‐uniform conditions (temperatures and solar irradiances) are presented here. The fast response and the accurate tracking to the maximum power point (MPP) with considerable reduction in the oscillations are successfully reached with the developed controller which is much better than sliding mode controller. [ABSTRACT FROM AUTHOR]

Microwave ablation (MWA) provides an effective treatment of lung and liver tumors but suffers from a lack of reproducibility of ablation size among currently available technologies. In-vitro evaluations are far removed from clinical practices because of uninfused tissue. This study is in-vivo preclinical testing of a new MWA system on swine lungs and liver. All ablations were performed under CT guidance and multiple algorithms were tested with a power of 50, 75, and 100 W for durations of 3, 5, 8, 10, and 15 min. A 3 D-evaluation of the ablation zone was carried out using enhanced-CT. The sphericity index, coefficients of variation, and energy efficiency (which corresponds to the volume yield according to the power supplied) were calculated. Fifty liver and 48 lung ablations were performed in 17 swine. The sphericity index varies from 0.50 to 0.80 for liver ablations and from 0.40 to 0.69 for lung ablations. The coefficient of variation was below 15% for 4/5 and 4/8 protocols for lung and liver ablations, respectively. The energy efficiency seems to decrease with the duration of the ablation from 0.60 × 10−3 cm3/J (75 W, 3 min) to 0.26 × 10−3 cm3/J (100 W, 15 min) in the liver and from 0.57 × 10−3 cm3/J (50 W, 10 min) to 0.42 × 10−3 cm3/J (100 W, 12 min) in the lungs. A shorter treatment time provides the best energy efficiency, and the best reproducibility is obtained for a 10 min treatment duration. The system tested provides an interesting reproducibility in both lung and liver measurements. Our results may help interventional radiologists in the optimal selection of treatment parameters. [ABSTRACT FROM AUTHOR]

Radiofrequency ablation (RFA) is a safe and effective minimally invasive treatment for pulmonary tumors. Patterns on chest computed tomography (CT) after RFA are classified into five types; however, the follow-up has not been fully described. The objectives of this study were to describe (1) the CT pattern 3 years after RFA and (2) its evolution over 7 years. Lesions treated with RFA between 2009 and 2017 and with ≥3 years of follow-up CT data were included. Lesions with local recurrences were excluded from the study. The morphology of the ablation zone was classified as nodular, fibrotic, atelectatic, cavitary, and disappeared. Other initial anatomical parameters were recorded. Kruskal–Wallis or Chi-square tests were used to compare the groups. One hundred lung RFA scars were included, and a retrospective longitudinal study was performed. Three years after RFA, nodular, fibrotic, atelectatic, and cavitary scars, and disappearance were observed in 49%, 36%, 5%, 3%, and 6% of the scars, respectively. Evolution over 7 years showed that the fibrosis, atelectasis, and disappearance remained stable over time, whereas 28% of nodular scars evolved into fibrotic scars. Additionally, 45% of cavitary scars evolved into nodular scars. Pleural contact was associated with disappearance, and the use of a 20-mm needle was associated with atelectasis. Follow-up after RFA showed that fibrosis, disappearance, and atelectasis remained stable over time. Nodular scars could evolve into fibrotic scars, and cavitary scars could evolve into nodular scars. [ABSTRACT FROM AUTHOR]

Purpose: To determine the impact of the COVID-19 on the CT activities in French radiological centers during the epidemic peak. Materials and methods: A cross-sectional prospective CT scan survey was conducted between March 16 and April 12, 2020, in accordance with the local IRB. Seven hundred nine radiology centers were invited to participate in a weekly online survey. Numbers of CT examinations related to COVID-19 including at least chest (CTcovid) and whole chest CT scan activities (CTchest) were recorded each week. A sub-analysis on French departments was performed during the 4 weeks of the study. The impact of the number of RT-PCRs (reverse transcriptase polymerase chain reactions) on the CT workflow was tested using two-sample t test and Pearson's test. Results: Five hundred seventy-seven structures finally registered (78%) with mean response numbers of 336 ± 18.9 (323; 351). Mean CTchest activity per radiologic structure ranged from 75.8 ± 133 (0–1444) on week 12 to 99.3 ± 138.6 (0–1147) on week 13. Mean ratio of CTcovid on CTchest varied from 0.36 to 0.59 on week 12 and week 14 respectively. There was a significant relationship between the number of RT-PCR performed and the number of CTcovid (r = 0.73, p = 3.10−16) but no link with the number of positive RT-PCR results. Conclusion: In case of local high density COVID-19, CT workflow is strongly modified and redirected to the management of these specific patients. Key Points: • Over the 4-week survey period, 117,686 chest CT (CTtotal) were performed among the responding centers, including 61,784 (52%) CT performed for COVID-19 (CTcovid). • Across the country, the ratio CTcovid/CTtotalvaried from 0.36 to 0.59 and depended significantly on the local epidemic density (p = 0.003). • In clinical practice, in a context of growing epidemic, in France, chest CT was used as a surrogate to RT-PCR for patient triage. [ABSTRACT FROM AUTHOR]

Introduction: COVID-19 presents benign forms in young patients who frequently present with anosmia. Infants are rarely infected, while severe forms occur in patients over 65 years of age with comorbidities, including hypertension and diabetes. Lymphopenia, eosinopenia, thrombopenia, increased lactate dehydrogenase, troponin, C-reactive protein, D-dimers and low zinc levels are associated with severity.Areas covered: The authors review the literature and provide an overview of the current state of knowledge regarding the natural history of and therapeutic options for COVID-19. Expert opinion: Diagnosis should rely on PCR and not on clinical presumption. Because of discrepancies between clinical symptoms, oxygen saturation or radiological signs on CT scans, pulse oximetry, and radiological investigation should be systematic. The disease evolves in successive phases: an acute virological phase, and, in some patients, a cytokine storm phase; an uncontrolled coagulopathy; and an acute respiratory distress syndrome. Therapeutic options include antivirals, oxygen therapy, immunomodulators, anticoagulants and prolonged mechanical treatment. Early diagnosis, care, and implementation of an antiviral treatment; the use of immunomodulators at a later stage; and the quality of intensive care are critical regarding mortality rates. The higher mortality observed in Western countries remains unexplained. Pulmonary fibrosis may occur in some patients. Its future is unpredictable. [ABSTRACT FROM AUTHOR]

Background: Low-dose chest CT (LDCT) showed high sensitivity and ability to quantify lung involvement of COVID-19 pneumopathy. The aim of this study was to describe the prevalence and risk factors for lung involvement in 247 patients with a visual score and assess the prevalence of incidental findings. Methods: For 12 days in March 2020, 250 patients with RT-PCR positive tests and who underwent LDCT were prospectively included. Clinical and imaging findings were recorded. The extent of lung involvement was quantified using a score ranging from 0 to 40. A logistic regression model was used to explore factors associated with a score ≥ 10. Results: A total of 247 patients were analyzed; 138 (54%) showed lung involvement. The mean score was 4.5 ± 6.5, and the mean score for patients with lung involvement was 8.1 ± 6.8 [1–31]. The mean age was 43 ± 15 years, with 121 males (48%) and 17 asymptomatic patients (7%). Multivariate analysis showed that age > 54 years (odds ratio 4.4[2.0–9.6] p < 0.001) and diabetes (4.7[1.0–22.1] p = 0.049) were risk factors for a score ≥ 10. Multivariate analysis including symptoms showed that only age > 54 years (4.1[1.7–10.0] p = 0.002) was a risk factor for a score ≥ 10. Rhinitis (0.3[0.1–0.7] p = 0.005) and anosmia (0.3[0.1–0.9] p = 0.043) were protective against lung involvement. Incidental imaging findings were found in 19% of patients, with a need for follow-up in 0.6%. Conclusion: The prevalence of lung involvement was 54% in a predominantly paucisymptomatic population. Age ≥ 55 years and diabetes were risk factors for significant parenchymal lung involvement. Rhinitis and anosmia were protective against LDCT abnormalities. [ABSTRACT FROM AUTHOR]

A study of the non-inverting amplifier based on a two stages CMOS unbuffered current-feedback-operational-amplifier (UCFOA) is proposed in this paper. Using a small-signal equivalent circuit (macro-model) of the non-inverting amplifier, a theoretical explanation of the closed loop gain is given. The opamp phase margin and its bandwidth have been estimated from the quality factor Q of resonance and using a novel description of the UCVFOA input stage called Operational Transconductance Conveyor (OTC). The OTC description can be seen as an extension of type II second generation current conveyors. Based on the fundamental parameters of the proposed OTC, a theoretical approach given in this paper explains how to evaluate precisely the value of the UCFOA compensation capacitance. PSPICE was used to simulate both the theoretical macro-model and the CMOS configuration from a 0.35 μm typical BSIM3V3 transistor models. [ABSTRACT FROM AUTHOR]

Maximum Power Point Tracking (MPPT) methods are used in photovoltaic (PV) systems to continually maximize the PV array output power, which strongly depends on both solar radiation and cell temperature. The PV power oscillations around the maximum power point (MPP) resulting from the conventional methods and complexity of the non-conventional ones are convincing reasons to look for novel MPPT methods. This paper deals with simple Genetic Algorithms (GAs) based MPPT method in order to improve the convergence, rapidity, and accuracy of the PV system. The proposed method can also efficiently track the global MPP, which is very useful for partial shading. At first, a review of the algorithm is given, followed with many test examples; then, a comparison by means Matlab/Simulink© (R2009b) is conducted between the proposed MPPT and, the popular Perturb and Observe (PO) and Incremental Conductance (IC) techniques. The results show clearly the superiority of the proposed controller. Indeed, with the proposed algorithm, oscillations around the MPP are dramatically minimized, a better stability is observed and increase in the output power efficiency is obtained. All these results are experimentally validated by a test bench developed at LIAS laboratory (Poitiers University, Poitiers, France) using real PV panels and a PV emulator which allows one to define a profile insolation model. In addition, the proposed method permits one to perform the test of linearity between the optimal current Imp (current at maximum power) and the short-circuit current Isc, and between the optimal voltage Vmp and open-circuit voltage Voc, so the current and voltage factors can be easily obtained with our algorithm. [ABSTRACT FROM AUTHOR]

Objectives: The incidence of pneumothorax is 7 times higher after lung radiofrequency ablation (RFA) than after lung biopsy. The reasons for such a difference have never been objectified. The histopathologic changes in lung tissue are well-studied and established for RF in the ablation zone. However, it has not been previously described what the nature of thermal injury might be along the shaft of the RF electrode as it traverses through normal lung tissue to reach the ablation zone. The purpose of this study was to determine the changes occurring around the RF needle along the pathway between the ablated zone and the pleura. Material and methods: In 3 anaesthetised and ventilated swine, 6 RFA procedures (right and left lungs) were performed using a 14-gauge unipolar multi-tined retractable 3 cm radiofrequency LeVeen probe with a coaxial introducer positioned under CT fluoroscopic guidance. In compliance with literature guidelines, we implemented a gradually increasing thermo-ablation protocol using a RF generator. Helical CT images were acquired pre- and post-RFA procedure to detect and evaluate pneumothorax. Four percutaneous 19-gauge lung biopsies were also performed on the fourth swine under CT guidance. Swine were sacrificed for lung ex vivo examinations, scanning electron microscopy (SEM) and pathological analysis. Results: Three severe (over 50 ml) pneumothorax were detected after RFA. In each one of them, pathological examination revealed a fistulous tract between ablation zone and pleura. No fistulous tract was observed after biopsies. In the 3 cases of severe pneumothorax, the tract was wide open and clearly visible on post procedure CT images and SEM examinations. The RFA tract differed from the needle biopsy tract. The histological changes that are usually found in the ablated zone were observed in the RFA tract's wall and were related to thermal lesions. These modifications caused the creation of a coagulated pulmonary parenchyma rim between the thermo-ablation zone and the pleural space. The structural properties of the damage can explain why the RFA tract is remains patent after needle withdrawal. Conclusion: Our study demonstrates for the first time that the changes around the RF needle are the same as in the ablated zone. The damage could create fistulous tracts along the needle path between thermo-ablation zone and pleural space. These fistulas could certainly be responsible for severe pneumothorax that occurs in many patients treated with lung RFA. [ABSTRACT FROM AUTHOR]

Purpose: Pneumothorax is the most common complication following a pulmonary percutaneous radiofrequency ablation (RFA), and thoracic drainages are the most frequent causes of an extended hospital stay. Our main objective was to show that the use of gelatin torpedoes may significantly decrease the number of chest tube placement. Materials and methods: Seventy-three patients were prospectively included in this study and then randomised into two groups: 34 with embolisation and without 39 without embolisation. Each group was comparable for different pneumothorax risk factors. Results: There were 16 (47%) pneumothorax in Group A ("with embolisation"), which was significantly lower (p<.0001) than the 35 pneumothorax (90%) in Group B ("without embolisation"). The pneumothorax volume (p=.02) was significantly lower in Group A (22.7% average, standard deviation 15.6%) than in Group B (average 34.1%, standard deviation 17.1%). The number of drainages was significantly smaller in those with embolisation (3 drainages or 8%) than those without embolisation (25 drainages or 64%) (p<.001). Conclusion: When using absorbable gelatin torpedoes, pulmonary RFA pathways embolisation significantly decreased the number of pneumothorax and thoracic drainages to the advantage of therapeutic abstention and exsufflation, non-invasive and functional operational techniques. [ABSTRACT FROM AUTHOR]

Purpose:The risk factors of pneumothorax after lung radiofrequency (RF) ablation are long known. The objective was to demonstrate that the visualisation of an aeric RF path after the needle withdrawal was predictive of pneumothorax occurrence and chest tube placement. Materials and methods:A total of 70 patients were retrospectively included in this study. For each patient, we determined the pneumothorax risk factors (age, gender, previous surgery, emphysema, lesion size, distance between pleura and lesion), visualisation of a RF track, length and thickness, presence of pneumothorax, volume, chest tube placement, duration of drainage and hospital stay. Results:Among 70 patients included retrospectively, 26 needed a chest tube placement (37%). Considering the group with path visualisation (37 patients, group A) and the patients without path visualisation (group B), the 2 groups were comparable for pneumothorax risk factors. Considering the patients who needed a chest drain, the visualisation of the path was significatively more important (23 cases, 88.4%) (p< 10−3) than in the group without (8 patients, 31.8%). Multivariate analyses were significant in the three analyses after adjustments on the risk factors for the occurrence of pneumothorax. Incidence of drains was significantly more (p < 10−3) important in group A (23 drainages 62%) than in group B (4 drainages or 12%). The length and thickness of the tracks were not predictable of drain placement. Conclusions:Besides the well-known risk factors of severe pneumothorax after lung RFA, the simple visualisation of an aeric path just after the RF needle withdrawal is significantly associated with chest tube placement and can be considered as a risk factor as itself. [ABSTRACT FROM AUTHOR]

Purpose:Detecting a recurrence after lung radiofrequency ablation (RFA) is based on a group of arguments that include CT, positron emission tomography (PET-CT) at 3 months and clinical patient follow-up. There is no one examination that is absolutely reliable. Recurrences are diagnosed tardily, when the cancers are locally extended, or when the patients are metastatic. The purpose of this article is to investigate the utility of dual-energy computed tomography (DECT) in order to assess therapeutic responses to RFA for lung neoplasia. Materials and methods:This institutional review board-approved study enroled 70 patients with lung tumours who underwent DECT after RFA. All patients provided a written informed consent for the study. Results:The study included 70 consecutive patients, and 191 DECT measures were performed. We collected the enhancement values of all scars without establishing a prior threshold of positivity. The optimal threshold value areas appeared to be located between 20 and 35 Hounsfield unit(HU) with sensitivity between 70% and 82%; specificity between 72% and 90%; a negative predictive value (NPV) between 96% and 97% and a diagnostic accuracy index between 73% and 87%. At the one month follow-up, 53 nodules were analysed with DECT and four nodules had recurred, all of which were detected by DECT. The sensitivity, which was calculated at 100%, was excellent; the NPV was at 100% (CI: 91.62, 100) and the specificity was at 85.71% (CI: 73.33, 92.9). The diagnostic accuracy index was 86.79% (CI: 75.16, 93.45) and the average DECT acquisitions dosimetry was 106 mGy.cm (33mGy.cm 245mGy.cm). Conclusion:DECT could be a conceivable alternative for detecting early recurrence after lung RFA.Key pointsAfter lung RFA, a PET CT has a high rate of false positives in the initial phase;The study of enhancement in the follow-up of lung lesions treated with RFA, and especially by DECT, can be relevant;Dual Energy CT has a good efficiency for a threshold between 20 and 35 HU, especially in the first month after RFA;DECT could be a conceivable alternative for detecting early recurrence. [ABSTRACT FROM PUBLISHER]

A self-duty-cycled non-coherent impulse radio-ultra wideband receiver targeted at low-power and low-data-rate applications is presented. The receiver is implemented in a 130 nm CMOS technology and works in the 7.2-8.5 GHz UWB band, which covers the IEEE 802.15.4a and 802.15.6 mandatories high-band channels. The receiver architecture is based on a non-coherent RF front-end (high gain LNA and pulse detector) followed by a synchronizer block (clock and data recovery or CDR function and window generation block), which enables to shut down the power-hungry LNA between pulses to strongly reduce the receiver power consumption. The main functions of the receiver, i.e. the RF front-end and the CDR block, were measured stand-alone. A maximum gain of 40 dB at 7.2 GHz is measured for the LNA. The RF front-end achieves a very low turn-on time (<1 ns) and an average sensitivity of −92 dBm for a 10 BER at a 1 Mbps data rate. A root-mean-square (RMS) jitter of 7.9 ns is measured for the CDR for a power consumption of 54 µW. Simulation results of the fully integrated self-duty-cycled 7.2-8.5 GHz IR-UWB receiver (that includes the measured main functions) confirm the expected performances. The synchronizer block consumes only 125 µW and the power consumption of the whole receiver is 1.8 mW for a 3% power duty-cycle (on-window of 30 ns). [ABSTRACT FROM AUTHOR]

Most maximum power point tracking (MPPT) techniques based on sliding‐mode control (SMC) use another method such as perturb and observe or incremental conductance (IncCond) to provide current or voltage reference which makes the system more complex. To reduce the complexity and to increase the photovoltaic (PV) array efficiency, a direct control high‐performance MPPT based on improved SMC has been investigated in this study. Using two different step sizes can follow the PV peak power at different operating conditions with rapid convergence and greater accuracy. The new SMC‐based MPPT designed for boost‐type DC/DC converters is compared with a conventional and modified IncCond method, and to a classical SMC method which is very similar to that applied by Chu et al. The proposed PV‐MPPT system is tested during a stringent profile of sunshine variation as recommended by the European Norm 50530, by simulation within MATLAB/SimulinkTM tools and verified by implementation using a test bench based on DS1104 R&D controller board. The obtained results are satisfactory and demonstrate that the new SMC can track the MPP quickly within 0.003 s and with good accuracy close to 99%. [ABSTRACT FROM AUTHOR]

In this article, a grid-connected photovoltaic system with functionality of power quality enhancement is studied. The integration of the photovoltaic generator into the grid takes place in one stage, using a three-phase voltage source inverter. A direct power control algorithm strategy with a new switching table has been proposed to decrease power losses into the voltage source inverter, to enhance power quality, to optimize the control of instantaneous active and reactive powers, and to perform as a multi-function device by incorporating shunt active power filter functionality. In addition to this control strategy, a maximum power point tracking perturb and observe algorithm is applied to the inverter to extract optimal available power from the photovoltaic array. The proposed system can provide the power factor correction, harmonic elimination, reactive power compensation, and simultaneously inject the maximum power available from the photovoltaic array to the load and/or grid. The multifunctional features of the proposed control algorithm are demonstrated using extensive simulation studies and are validated through experimental results. [ABSTRACT FROM AUTHOR]

This paper proposes a fuzzy control method for tracking maximum power point in photovoltaic (PV) power systems to solve a fast irradiation change problem. Perturb and Observe (P&O) is known as a very simple maximum power point tracking and is extensively disseminated. Fuzzy logic is also simple to investigate and provides fast dynamics. The suggested technique combines both fuzzy logic and P&O advantages. A fuzzy logic-based P&O algorithm is illustrated to identify the fault direction tracking of conventional P&O algorithm under trapezoidal irradiation change. The proposed algorithm is verified using Matlab/Simulink™ software. The robust tracking capability under rapidly increasing and decreasing irradiance is verified experimentally with a PV array emulator. Simulation and experimental results confirm that the proposed algorithm provides effective, fast, and accurate tracking compared to the conventional P&O algorithm. [ABSTRACT FROM AUTHOR]

This article deals with shunt active power filtering for power quality improvement with hysteresis current controllers by two methods of implementation assessed under unfavorable non-linear load and source conditions. Fully digital and simple hybrid hysteresis control strategies are tested based on a numerical integrator proportional DC bus controller combined with phase-locked loop outputs to generate current references. In two cases, reference mains currents are generated to ensure three-phase sinusoidal synchronized waveforms of the mains currents. The experimental evaluation of the robustness control in these two implementation methods is verified using a 10-kVA shunt active power filter in steady state for transitional conditions (step load, switch-on of shunt active power filter) and in the worst case of unbalanced loads (break phase) and source voltages. Several experimental results are presented and discussed to prove the robustness and excellent performance of the proposed simple hybrid technique. [ABSTRACT FROM AUTHOR]

This paper presents the design of a fully integrated ultra-low-power Ultra Wide Band (UWB) pulse generator. The circuit is designed and optimized for low rate and localization applications. This UWB transmitter is based on the impulse response filter method in order to achieve high energy sub-nanosecond pulses. The circuit has been integrated in a ST-Microelectronics CMOS 0.13 µm technology with a supply voltage of 1.2 V on a die area of 0.56 mm². A power manager is used to reduce the power leakages to 3.91 MW which gives a power consumption of 3.98 Mw at 10 kb/s. The measured dynamic energy consumed per pulse is 68 pJ and the measured energy of the emitted pulse is 2.15 pJ. [ABSTRACT FROM AUTHOR]

In this paper, we propose a low-power technique, called RF power gating, which consists in varying the active time ratio (ATR) of the RF front end at a symbol time scale. This technique is especially well suited to adapt the power consumption of the receiver to the performance needs without changing its architecture. The effect of this technique on the bit error rate (BER) performances is studied for a basic estimator in the specific case of minimum-shift keying signaling. A system-level energy model is also derived and discussed to estimate precisely the power reduction based on the characteristics and the power consumption of each block. This model allows highlighting the different contributors of the power reduction. The BER results and the energy model are finally merged to determine the best ATR meeting the design constraints. Applying this technique to the IEEE 802.15.4 standard, this paper shows that an ATR of 20% is a good tradeoff to meet the packet error rate constraint while maximizing the energy reduction ratio. Using typical block power consumptions, an energy reduction ratio around 20% can be reached. Even better energy reduction ratios ( $\sim 60$ %) are also achievable when most of the blocks are power-gated. [ABSTRACT FROM AUTHOR]

The choice and design of a high efficient maximum power point tracking (MPPT) algorithm is a necessity in the PV system design. Many approaches have been proposed in literature, among them, the methods that are based on perturb and observe (P&O), widely used in commercial products due their simplicity and ease of implementation. In this paper, a new modified P&O (MPPT) method with adaptive duty cycle step size using fuzzy logic controller is proposed. Both, simulation and experimental design are provided in several aspects. The proposed and classical methods are developed and tested successfully using a CUKDC-DC converter, which is connected to a SunTech STP085B model. The proposed method is able to improve the dynamic response and steady-state performance of the PV systems simultaneously and effectively. In addition, analysis and comparison with the conventional fixed step size P&O have been presented. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: Pre-therapeutic pathological diagnosis is a crucial step of the management of pulmonary nodules suspected of being non small cell lung cancer (NSCLC), especially in the frame of currently implemented lung cancer screening programs in high-risk patients. Based on a human ex vivo model, we hypothesized that an embedded device measuring endogenous fluorescence would be able to distinguish pulmonary malignant lesions from the perilesional lung tissue. Methods: Consecutive patients who underwent surgical resection of pulmonary lesions were included in this prospective and observational study over an 8-month period. Measurements were performed back table on surgical specimens in the operative room, both on suspicious lesions and the perilesional healthy parenchyma. Endogenous fluorescence signal was characterized according to three criteria: maximal intensity (Imax), wavelength, and shape of the signal (missing, stable, instable, photobleaching). Results: Ninety-six patients with 111 suspicious lesions were included. Final pathological diagnoses were: primary lung cancers (n = 60), lung metastases of extra-thoracic malignancies (n = 27) and non-tumoral lesions (n = 24). Mean Imax was significantly higher in NSCLC targeted lesions when compared to the perilesional lung parenchyma (p<0,0001) or non-tumoral lesions (p<0,0001). Similarly, photobleaching was more frequently found in NSCLC than in perilesional lung (p<0,0001), or in non-tumoral lesions (p<0,001). Respective associated wavelengths were not statistically different between perilesional lung and either primary lung cancers or non-tumoral lesions. Considering lung metastases, both mean Imax and wavelength of the targeted lesions were not different from those of the perilesional lung tissue. In contrast, photobleaching was significantly more frequently observed in the targeted lesions than in the perilesional lung (p≤0,01). Conclusion: Our results demonstrate that endogenous fluorescence applied to the diagnosis of lung nodules allows distinguishing NSCLC from the surrounding healthy parenchyma and from non-tumoral lesions. Inconclusive results were found for lung metastases due to the heterogeneity of this population. [ABSTRACT FROM AUTHOR]

This paper proposes a new Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) algorithm for Small Wind Energy Conversion Systems to overcome the rapidity-efficiency trade-off and wrong behavior problems of the conventional P&O technique. The proposed algorithm works in two separate modes. The first mode is activated when the wind speed changes slowly. Under a rapid change of the wind speed, the second mode is switched to avoid the divergence of the system. The proposed algorithm requires only the measurement of the dc-link voltage and the dc current to realize the MPPT control, so no rotor speed measurement is needed, reducing the complexity of the overall system. The performance and the validity of the new MPPT algorithm have been proved by both simulation and experimental results. [ABSTRACT FROM AUTHOR]

In this paper, the impact on the bit error rate (BER) of the periodic non-uniform sampling implied by a power-gated analog-to-digital converter (ADC) is addressed in the specific case of a binary CPFSK receiver. Analytical and simulated lower bounds of the BER in an additive white Gaussian noise channel for several phase-based estimators are presented and discussed together with their dependency on the sampling synchronization. The main results are summarized in a practical abacus for Minimum Shift-Keying (MSK) modulation. Finally, the proposed techniques are evaluated against the IEEE 802.15.4 specification in MSK mode and lead to an active time ratio of the ADC of only 10% or less. Application of the proposed technique to a more competitive IEEE 802.15.4 compliant architecture available in the literature is also presented. [ABSTRACT FROM PUBLISHER]