Role of hyaluronic acid intrauterine injection in the prevention of Asherman’s syndrome in women undergoing uterine septum resection: An RCT

Background: Adhesion due to intrauterine surgery such as septal resection associated with damaged endometrium can increase the risk of Asherman’s syndrome. The main goal of treatment in this syndrome is to repair the damaged endometrium for creating a physiological pregnancy. Objective: To investigate the effect of intrauterine injection of hyaluronic acid on the prevention of Asherman’s syndrome in women undergoing uterine septum resection. Materials and Methods: In this double-blind randomized clinical trial, 65 women undergoing the uterine septum resection were divided into two groups; the case group (n = 34) and the control group (n = 31). Immediately after the septal resection with a resectoscope, 1cc of hyaluronic acid gel in the case group and 1cc normal saline solution as a placebo in the control group was injected into the uterine cavity. After two months, existence of intrauterine adhesions in the both groups was examined by the hysteroscope and assessment of menstrual patterns, according to the American Society for Reproductive Medicine criteria. Results: Our results showed that after intervention, the incidence of Asherman’s syndrome in the control group was higher than the case group (p = 0.012). In the case group, only four women had poor adhesion (Asherman’s syndrome) at the end of the study, while the rest of them were free of any adhesions in the uterine cavity. In the control group, however, only 19 were free of intrauterine adhesions and 12 had mild symptoms. Conclusion: The results of the study exhibited the hyaluronic acid capacity to reduce the risk of Asherman’s syndrome in women with endometrial damage following a septal resection surgery. Key words: Asherman’s syndrome, Septum, Uterine, Hyaluronic acid, Resection

Operational Strategies for Establishing Disaster-Resilient Schools: A Qualitative Study

Introduction: Resilient schools can warranty students’ health and survival at disasters. It is obligatory that schools be prepared for natural challenges through local programs. Considering the great population of students, disaster-resilient schools can be a safe and suitable environment for students at the time of disaster. Objective: This study aims to identify certain operational strategies for establishing schools resilient to natural disasters. Method: This qualitative study was based on conventional content analysis. Using purposive sampling method, 24 experts in the fields of health in disasters, construction engineering, psychology, teaching, and administrative management participated in the study. Maximum variation sampling continued until data saturation was achieved. The data collected via unstructured interviews were analyzed with Graneheim and Lundmen’s conventional content analysis. Results: Content analysis resulted in four main categories as operational strategies for establishing disaster-resilient schools including: 1) “construction and non-construction optimization”, with four subcategories of construct risk management, optimization of construct architecture and physical structure, correct construct localization, and promotion of non-construct safety, 2) “promotion of organizational coordination and interactions” with two subcategories, namely improvement  in intra-organizational communication and improvement  in extra-organizational communication, 3) “improvement  in education” with three subcategories of holding educational courses for families and students, holding educational courses for managers and personnel, and holding simulated exercises, and 4) “process promotion” with four subcategories of increased preparedness, correct planning, creation of organizational structure, and rehabilitation facilitation. Conclusion: Various factors affecting schools’ response to disasters form operational strategies to establish disaster-resilient schools. These strategies influence pre- and post-disaster preparedness. Awareness of these components followed by preparedness prior to disasters can save students’ lives, improve school performance after disasters, and aid in establishing disaster-resilient schools as safe lodgings

Operational Strategies for Establishing Disaster-Resilient Schools: A Qualitative Study

Introduction: Resilient schools can warranty students’ health and survival at disasters. It is obligatory that schools be prepared for natural challenges through local programs. Considering the great population of students, disaster-resilient schools can be a safe and suitable environment for students at the time of disaster. Objective: This study aims to identify certain operational strategies for establishing schools resilient to natural disasters. Method: This qualitative study was based on conventional content analysis. Using purposive sampling method, 24 experts in the fields of health in disasters, construction engineering, psychology, teaching, and administrative management participated in the study. Maximum variation sampling continued until data saturation was achieved. The data collected via unstructured interviews were analyzed with Graneheim and Lundmen’s conventional content analysis. Results: Content analysis resulted in four main categories as operational strategies for establishing disaster-resilient schools including: 1) “construction and non-construction optimization”, with four subcategories of construct risk management, optimization of construct architecture and physical structure, correct construct localization, and promotion of non-construct safety, 2) “promotion of organizational coordination and interactions” with two subcategories, namely improvement  in intra-organizational communication and improvement  in extra-organizational communication, 3) “improvement  in education” with three subcategories of holding educational courses for families and students, holding educational courses for managers and personnel, and holding simulated exercises, and 4) “process promotion” with four subcategories of increased preparedness, correct planning, creation of organizational structure, and rehabilitation facilitation. Conclusion: Various factors affecting schools’ response to disasters form operational strategies to establish disaster-resilient schools. These strategies influence pre- and post-disaster preparedness. Awareness of these components followed by preparedness prior to disasters can save students’ lives, improve school performance after disasters, and aid in establishing disaster-resilient schools as safe lodgings

Barriers and Incentives of Self-care from the View of Diabetic Patients and their Service Providers Using the Social Marketing Model in Ardakan, Iran

Introduction: Diabetes is the most common disease worldwide. The complications of diabetes cause economic damages and decrease patients' and their families' quality of life. Self-care is an important process in diabetes control. On the other hand, maintaining the blood glucose level at a favorable level is challenging for both the patients and the physician. This is due to systemic and individual barriers of diabetes self-care. Thus, the present study aimed to explore the barriers and incentives for self-care. Method: The present study was conducted as a qualitative study with focus group discussion (FGD) (3 sessions for patients and 3 sessions for health care providers separately). Private interviews were conducted with 25 patients and 5 health care providers until data saturation. The interviews and FGDs were transcribed and analyzed using content analysis method. Results: In analyzing the data, two main themes including barriers and incentives for self-care from the view of patients and health care providers were extracted. Based on the social marketing model, these themes were divided into four subthemes of product, place, price, and promotion. The study subjects specified the different causes of performing or not performing self-care in different areas such as exercise, nutrition, regular medical exams, and appropriate medicine use. The cost and availability of some services, physical barriers and their limitations, nonscientific health care delivery, unsuitable health care services for diabetic patients, and lack of health care packages and guidelines were reported as barriers. Moreover, successful experiences of patients and health care providers, and providing self-care facilities were reported as incentives. Conclusion: Market analysis in diabetes self-care showed that comprehensive and systematic programs for diabetic patient care, management protocol for physicians and specialists, and nutritional recommendation, traditional medicine, and exercise are more beneficial when coordinated with economic power, environmental factors, and beliefs of diabetic patients and literacy promotion Keywords: Diabetes, Social marketing, Self-care, Barriers and incentives, Qualitative researc

Grid-Connected Energy Storage Systems: State-of-the-Art and Emerging Technologies

High penetration of renewable energy resources in the power system results in various new challenges for power system operators. One of the promising solutions to sustain the quality and reliability of the power system is the integration of energy storage systems (ESSs). This article investigates the current and emerging trends and technologies for grid-connected ESSs. Different technologies of ESSs categorized as mechanical, electrical, electrochemical, chemical, and thermal are briefly explained. Especially, a detailed review of battery ESSs (BESSs) is provided as they are attracting much attention owing, in part, to the ongoing electrification of transportation. Then, the services that grid-connected ESSs provide to the grid are discussed. Grid connection of the BESSs requires power electronic converters. Therefore, a survey of popular power converter topologies, including transformer-based, transformerless with distributed or common dc-link, and hybrid systems, along with some discussions for implementing advanced grid support functionalities in the BESS control, is presented. Furthermore, the requirements of new standards and grid codes for grid-connected BESSs are reviewed for several countries around the globe. Finally, emerging technologies, including flexible power control of photovoltaic systems, hydrogen, and second-life batteries from electric vehicles, are discussed in this article.This work was supported in part by the Office of Naval Research Global under Grant N62909-19-1-2081, in part by the National Research Foundation of Singapore Investigatorship under Award NRFI2017-08, and in part by the I2001E0069 Industrial Alignment Funding. (Corresponding author: Josep Pou.

Novel Fast-Speed Partial-Shading-Tolerant Flexible Power Point Tracking for Photovoltaic Systems with Explicit Key Points Estimation

Recent power curtailment-based photovoltaic (PV) flexible power point tracking (FPPT) algorithms mainly adopted intricate curve fitting or sophisticated curve-scanning mecha-nisms to ensure the grid supportive functionalities under partial shading conditions (PSCs), showing the limitations of mathe-matical solidity or system dynamics improvement. Accordingly, a novel fast-speed partial-shading-tolerant FPPT (PST-FPPT) algorithm is proposed in this paper. Regarding the proposed scheme, a modified explicit PV model is developed to express the key operation points with the assistance of several representative current-voltage samples from the initialization process, which is beneficial to computational burden reduction and irradiance sensors removal. Additionally, to guarantee the tracking speed to system dynamics, a set point estimation-based direct voltage regulation strategy is proposed in this paper, eliminating the redundant searching in approaching the predefined power com-mand. Simulation and experimental evaluations under various PSCs and operational circumstances validated the effectiveness of the proposed control

Exploring Barriers and Facilitators of Inter-Organizational Management in Response to Mass Casualty Traffic Incidents: A Qualitative Study

Objective: To investigate and understand the current status of inter-organizational management in relief organizations as well as the relief organizations personnel behavior when facing mass traffic incidents (MCTI). The inter-organizational barriers and facilitators are also discussed in response to MCTI management and in order to help direct future actions to improve pre-hospital emergency services. Methods: The current qualitative study was performed through face-to-face, semi-structured interviews with 31 individuals from pre-hospital emergency services authorities and personnel, Red Crescent and Yazd, Kohgiluyeh and Boyer-Ahmad, Fars, and Qom provinces police. These provinces were selected by purposive sampling in 2018-2019. The conventional content analysis method was applied to analyze the data in this research. Results: Three main categories and 14 subcategories were determined. The categories are including relief organizations coordination (having four subcategories: independent relief organizations, interdepartmental services integration, insufficient knowledge of organizations about one other, and performance based on job descriptions), resource and infrastructure management (having four subcategories: adverse information management, proper information management, lack of medical resources and capacities considered, and upgrading of medical resources and capacities considered), and response management of relief organizations (having six subcategories: incomplete assessment, improving the quality of assessment, weakness in establishing scene security, scene security management, poor response, and cooperation in response). Conclusion: Relief organizations need to perform under a unified command. It has inter-organizational cooperation and provide integration of interdepartmental services in order to manage responsiveness at the scene. It also prevents an independent, chaos, and inability of the injured to properly understand and needs in MCTI

Operation of grid-connected photovoltaic power plants during voltage sags

Renewable energy sources are occupying an increasing share in the global power generation market. Among various renewable energy sources, photovoltaic (PV) technology has been in the focus of many governments and, supported substantial subsidies has resulted a steep increase in the installed capacity. Moreover, with the decreasing trend in the PV panel costs from $4.90/W in 1998 to$0.3/W in 2015, the rate of growth of new PV installations is expected to remain at a high level. With high penetration of installed distributed generation (DG) units, power system operators (PSOs) are facing new challenges such as reliability, availability and power quality. In order to maintain the power quality and reliability of the power system, medium and large-scale grid-connected photovoltaic power plants (GCPVPPs) should possess low-voltage ride-through (LVRT) capability, as regulated by new standards and grid codes. Therefore, improved GCPVPP structures with LVRT capabilities in combination with efficient control strategies are necessary. Accordingly, the detailed operation of medium- and large-scale GCPVPPs during voltage sags is studied in this thesis. A typical two-stage multi-string PVPP consists of a dc/dc converter in each PV string and one central inverter. It is commonly recognized as one of state of the art configurations for medium- and large-scale GCPVPPs, due to its inherent advantages. Multilevel converters have emerged as the most viable solutions for high power energy conversion applications due to their capability of delivering excellent power quality with low harmonic contents and better efficiency, compared to the two-level converters. Therefore, multilevel converters have been proposed and discussed for multi-string GCPVPPs in this thesis. Firstly, the operation of the GCPVPP with three-level neutral-point-clamped (3l-NPC) inverter with balanced current injection to the grid during voltage sags is investigated. An algorithm for the calculation of current references, in the dq-frame, during voltage sags is introduced, which considers the inverter current limitation, grid code requirements and the amount of extracted power from photovoltaic strings. The proposed algorithm uses the full current capacity of the inverter in injecting active or reactive powers to the grid during voltage sags, which leads in a better grid voltage enhancement. The performance of proposed control strategy is investigated on a 150-kVA GCPVPP connected to the 12.47-kV medium-voltage test-case system simulation model during different voltage sag conditions. An experimental setup of the 3.3-kVA grid-connected three-level neutral-point-clamped inverter with a dc/dc converter illustrates and validates the performance of the controller in injecting required active/reactive power and supporting the network voltage. Secondly, the operation of GCPVPPs during unbalanced voltage sags with the injection of unbalanced currents to the grid is studied. This control strategy results into the zero active power oscillation during unbalanced voltage sags. An analytical expression for the calculation of active and reactive power references of a grid-tied inverter is proposed, which limits the peak current of the inverter during voltage sags. The key novelty is that the active/reactive power references are analytically calculated based on the dc-link voltage and grid codes, while they do not depend on the implemented current reference calculation algorithm and, as a general formulation, can be implemented in combination with various current reference calculation algorithms. Furthermore, based on the inverter nominal current and the injected reactive power to the grid during voltage sags, an analytical algorithm is introduced for the calculation of the active power reference, which can be extracted from PV strings. The proposed algorithm ensures that the maximum current capability of the inverter is used for the enhancement of the grid voltages during voltage sags, while it always complies with the reactive power injection requirement of grid codes and avoids increasing the dc-link voltage excessively. Experimental results of a grid-connected 3.3-kVA, 3L-NPC inverter laboratory prototype under several voltage sag conditions are presented to demonstrate the effectiveness of the proposed controller. The proposed unbalanced current injection algorithm is a general algorithm, which can be applied in various multilevel inverter topologies, however additional consideration on the operation of the inverter and voltage balancing of capacitors is required. Multilevel Cascaded H-Bridge (CHB) converters are one of the promising solutions for medium- and large-scale GCPVPPs. However, there is a lack of a complete study about their operation during voltage sags in the literature. Accordingly, a flexible control strategy is introduced for the operation of photovoltaic grid-connected CHB inverters during unbalanced voltage sags. The key novelty is that the proposed strategy is able to inject both active and reactive powers to the grid under either balanced or unbalanced currents, while ensuring that all dc-link capacitor voltages remain balanced. A zero-sequence voltage injection algorithm is proposed for inter-phase balancing, which allows for energy exchange between various phases. For inter-bridge balancing, the extracted power from different bridges of one phase is changed by modifying bridge voltage references. A feed-forward compensator is also applied to decrease the inverter transient current at the beginning of the voltage sag. The performance of the proposed control strategy is investigated on a 10-MVA photovoltaic power plant connected to a 6.6-kV medium-voltage test-case system simulation model. An experimental setup of a 9-kVA grid-connected seven-level CHB illustrates and validates the performance of the proposed strategy for the operation of the grid-connected CHB during different unbalanced voltage sags. One of the issues of the operation of GCPVPPs during voltage sags, is the reduction of the extracted power from PV strings to a certain power reference. During the voltage sag, both active and reactive power are injected to the grid through the inverter, therefore the amount of the injected active power is reduced compared to the grid normal operation. In order to obtain a constant dc-link voltage in the GCPVPP, the extracted power from PV strings should be equal to the injected power to the grid in all operating conditions (excluding power losses). Consequently, a constant power generation (CPG) algorithm from PV strings is introduced in this thesis, which reduces the extracted power from the PV string to the required power reference. An algorithm for the calculation of the photovoltaic panel voltage reference, which generates a constant power from the GCPVPP, is suggested. The key novelty of the proposed algorithm is its applicability for both single- and two-stage GCPVPPs and flexibility to move the operation point to the right- or left-side of maximum power point. Furthermore, the frequency of operation for the algorithm and voltage increments between consecutive operating points are modified based on a hysteresis band controller in order to obtain fast dynamic response under transients and low power oscillation during steady-state operation. The performance of the proposed algorithm for both single- and two-stage GCPVPPs is examined on a 50-kVA simulation setup of these topologies. Moreover, experimental results on a 1-kVA PV system validate the effectiveness of the proposed algorithm under various operating conditions, demonstrating the proposed CPG algorithm functionalities. The key contributions of this thesis can be summarized as: - A control strategy for the multi-string GCPVPP with neutral-point-clamped (NPC) inverter with LVRT capability is developed. - An active/reactive power control of photovoltaic grid-connected inverters with peak current limitation and zero active power oscillation during unbalanced voltage sags is proposed. - A flexible control of photovoltaic grid-connected cascaded H-bridge converters during unbalanced voltage sags is suggested. - A general constant power generation algorithm for photovoltaic systems is introduced. The proposed control strategies in this thesis enable the operation of medium- and large-scale GCPVPPs during voltage sags, while they achieve LVRT capability and comply with grid codes.Doctor of Philosophy (EEE

Active/Reactive Power Control of PV Grid-tied NPC Inverter Using 3-D Space Vector Modulation in abc Coordinate

Flexible active and reactive power injection to the grid is one of the requirements of medium-scale PV power plants (PVPP). Due to the high penetration of installed distributed generation (DG) units to the power system, the flexible active/reactive power control capability is necessary for medium-scale PVPPs in order to maintain the power quality and reliability of the power system. A three-dimensional space vector modulation (3-D SVM) in abc coordinate with combination of proportional-resonant (PR) controller is proposed for 4-wire NPC grid-connected inverter of the multi-string PVPP. The implementation of 3-D SVM in stationary coordinate (???? coordinate) for 4-wire multilevel inverters requires high computational complexity. However, in the proposed 3-D SVM which is implemented in abc coordinate, the computational complexity is decreased and flexible balanced/unbalanced active/reactive power injection capability is achieved. The performance of the proposed controller is investigated on the three-level neutral-point-clamped (NPC) inverter of a 10 kW grid-connected multi-string PVPP, which is considered as the state of the art for medium-scale PVPPs. Various operation conditions like partial shading of PV strings and balanced/unbalanced grid faults are implemented.ASTAR (Agency for Sci., Tech. and Research, S’pore)Accepted versio