Passive Clamping Circuit for Reduced Switch Count in Solid State Circuit Breakers

DC Solid-State Circuit Breakers (SSCB) play an important role in the protection of DC and hybrid AC/DC systems. As they operate mostly in on-state, the use of wide-bandgap devices, with low conduction losses, is an attractive solution. These devices need to be selected based on the rare occasion of fault breaking, with associated overcurrent and overvoltage intervals. In this work a novel clamping circuit, consisting in its simplified form of Metal-Oxide Varistors and capacitors, is proposed to be used in a DC SSCB. This circuit has the objective to reduce the breaker overvoltage during protection, enabling a lower number of required semiconductors in series and consequent overall reduced losses. An analysis of the idea and operation principle of the system is presented, alongside its stages of operation and defining equations. To evaluate its benefits, the system is compared with one typical passive solution. At the end a scaled prototype is tested, validating the benefits and theoretical analysis of the proposed approach

Investigation of Modular Multilevel Converters for E-STATCOM Applications

The power quality in electrical grids can be improved by static synchronous compensators (STATCOM), classically realized by low voltage inverters and conventional transformers. One of the main challenges for current and future STATCOM solution is the increase of flexibility for optimized power quality management by not only exchanging reactive power but also active power. For active power supply energy storage systems need to be integrated, classically at the dc link of the low voltage inverter. However, by the usage of classical low-voltage inverters, the power is quite limited even by parallel connection and bulky transformers are needed. Instead this paper suggests an E-STATCOM based on the modular multilevel converter (MMC) with integration of batteries at the dc link by isolated dc-dc conversion state. In this way, very high energy capacities can be installed and very high active and reactive power can be provided at very high efficiencies for safe and reliable grid operation

An analysis of combining dc circuit breaker and hybrid MMC with reduced number of FBSM for HVdc system protection

The hybrid modular multilevel converter (HMMC) is employing half-submodules (HBSMs) and full--bridge submodules (FBSMs), combining the advantages of both. Aiming to reduce the manufacture cost and power losses of such solution, this paper proposes an HMMC in combination with dc circuit breaker (CB) for MMC-based high-voltage direct current (HVdc) systems. Under such conditions, the characteristics of pole-to-pole permanent dc fault is analyzed. Simulation results considering a 150 MW/150 kV symmetrical monopole point-to-point MMC-based HVdc system demonstrate the effectiveness and feasibility of the proposed approach. In this way, the number of FBSM is reduced by about 60 % compared to typical HMMC solutions in the literature. Additionally, considering HMMC with dc CB solution, the peak value of dc fault current and the breaker voltage can be decreased by around 38 % and 50 %, respectively

Long-term Follow-up of Sexual Quality of Life after Laparoscopic Surgery in Patients with Deep Infiltrating Endometriosis

Study Objective: We performed a long-term follow-up to quantify the impairment of sexual quality of life (SQL) and health-related QL (HRQL) in sexually active women after laparoscopic excision of deep infiltrating endometriosis (DIE). Design: Prospective case-control study. Setting: Hospital Clinic of Barcelona. Patients: A total of 193 patients (after dropout and exclusions) were divided into 2 groups: one hundred twenty-nine premenopausal women with DIE (DIE group) and 64 healthy women who underwent tubal ligation (C group). Interventions: All patients underwent laparoscopic surgery: laparoscopic endometriosis surgery in the DIE group and laparoscopic tubal ligation in the C group. All women were followed for at least 36 months, and they completed the Medical Outcomes Study 36-item short form questionnaire to assess their HRQL and 3 self-administered questionnaires that evaluate different aspects of SQL: the generic Sexual Quality of Life−Female questionnaire, the Female Sexual Distress Scale to evaluate 'sexually related distress,' and the Brief Profile of Female Sexual Function to screen hypoactive sexual desire disorder. The patients with DIE as well as the controls completed the 4 questionnaires before surgery, and the patients with DIE also completed the questionnaires at 6 and 36 months after surgery. Measurements and Main Results: A comparison of the patients and controls before surgery showed a statistically significant impairment in SQL and HRQL among the patients with DIE. A statistically significant improvement in SQL and HRQL was observed in the DIE group 6 months after surgery, with scores being similar to those of the C group. An evaluation 36 months after surgery showed that SQL and HRQL were better than presurgical SQL and HRQL in the DIE group, with a slight reduction compared with the 6-month evaluation. Conclusion: SQL and HRQL improved in patients with DIE undergoing complete laparoscopic endometriosis resection and were comparable to those of healthy women at 6 months after surgery, showing a slight reduction at 36 months of follow-up

Influence of adhesive system on quartz fiber post dislocation resistance in endodontically treated teeth

To evaluate the dislocation resistance of the quartz fiber post/cement/dentin interface after different adhesion strategies. Methods: Forty bovine lower central incisors were selected and prepared with K-files using the step-back technique, and irrigated with 3 mL of distilled water preceding the use of each instrument. Prepared teeth were stored at 37ºC and 100% humidity for 7 days. The roots were prepared and randomized into 4 groups. The quartz fiber post was cemented with an adhesion strategy according to the following groups: GBisCem- BISCEM; GOneStep±C&B- One Step ± C&B; GAllBond±C&B- AllBond3 ± C&B; GAllBondSE±C&B- AllBondSE ±C&B with a quartz fiber post. Cross-sectional root slices of 0.7 mm were produced and stored for 24 h at 37° C before being submitted to push-out bond strength. Results: The mean and standard deviation values of dislocation resistance were GBisCem: 1.12 (± 0.23) MPa, GOneStep±C&B: 0.81 (± 0.31) MPa, GAllBond±C&B: 0.98 (± 0.14) MPa, and GAllBondSE±C&B: 1.57 (± 0.04) MPa. GAllBondSE±C&B showed significantly higher values of dislocation resistance than the other groups. Conclusions: Based on this study design, it may be concluded that adhesion strategies showed different results of quartz post dislocation resistance. Simplified adhesive system with sodium benzene sulphinate incorporation provided superior dislocation resistance

The economic burden of localized prostate cancer and insights derived from cost-effectiveness studies of the different treatments

Prostate cancer is one of the most frequent and impacting malignant neoplasms for men. In particular, localized prostate cancer has a notably high incidence and prevalence, despite which a solid consensus on treatment and procedure of care has not yet been reached. This article aims to shed light on this challenge by characterizing the economic burden and cost-effectiveness of different treatment strategies for localized prostate cancer after analyzing published comparable data from studies conducted in OECD countries

VIGIPÉ®: FOOT RISK STRATIFICATION TECHNOLOGY FOR PATIENTS WITH DIABETES MELLITUS

Objective: to create and validate an app that establishes the diabetic foot risk degree by associating the patients' health conditions.Methodology: a methodological study conducted between March 2019 and December 2021 in Crato – CE – Brazil, and divided into three phases: 1) Review of the national and international guidelines; 2) Creation of the educational technology; and 3) Face and content validation of the technology. This study followed the guidelines set forth in the Revised Standards for Quality Improvement Reporting Excellence guide.Results: in the review phase, similar content was identified between the guidelines for designing and organizing the content. The technology that was created enabled data collection, as well as diabetic foot risk assessment and classification. A total of 18 judges evaluated the instrument in the validation stage, obtaining a CVI value of 0.96.Conclusion: the study may contribute to improving the indicators referring to hospitalizations, amputations, reduced mobility, dependence, frailty and mortality resulting from diabetic foot

Recruitment characteristics and non-adherence associated factors of fibromyalgia patients in a randomized clinical trial : a retrospective survival analysis

Introduction: Fibromyalgia is a complex pain condition that affects mostly women. Given the disease's lack of understanding, patients report poor adherence to medication and mistrust of medical services. This study aims to describe the recruitment characteristics and non-adherence associated factors of fibromyalgia patients to an RCT. Methods: We performed a retrospective longitudinal analysis with data from our ongoing RCT. We investigated characteristics of subjects recruited, consented, and randomized. Adherence was studied using survival analysis techniques, and its associated factors were identified using Cox proportional hazards regression model. Results: 524 subjects were contacted, 269 were eligible, 61 consented and 40 subjects were randomized. Thirtyeight percent were non-adherent to the protocol with a median of visits of five. The recruitment survey reported that 90% would likely participate in RCTs, 52% had previous participation, and 19% were aware of RCTs by their physicians. Some barriers were investigator-related (staff's friendliness and receiving the results of their trial participation) and center-related (privacy-confidentiality issues and the institution's reputation), without difference between adherent and non-adherent participants. We report significant factors for non-adherence as VAS anxiety score of 5 or more (5.3 HR, p = 0.01), Body Mass Index (BMI) (0.91 HR, p = 0.041) and Quality of Life (QoL) – Personal development subdomain (0.89 HR, p = 0.046). Conclusion: Recruitment and adherence of fibromyalgia patients is a challenge; however, they seem eager to participate in RCTs. We recommend creating a comfortable, friendly and trusting environment to increase the recruitment rate. Higher anxiety, lower BMI and lower quality of life were associated with a higher attrition rate