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BackgroundMethodsResultsConclusionWith the increasing cases of TBI cases in the elderly population taking anticoagulants for comorbidities, there is a need to better understand the safety of new anticoagulants and how to manage anticoagulated TBI patients.A meta-analysis using a random-effect model was conducted to compare the effect of preinjury use of DOACs and VKAs on the outcomes following TBI.From 1951 studies, 49 studies with a total sample size of 15,180 met our inclusion criteria. Our meta-analysis showed no difference between preinjury use of DOACs or VKAs on ICH progression, in-hospital delayed ICH, delayed ICH at follow-up, and in-hospital mortality, but using DOACs was associated with a lower risk of immediate ICH (OR = 0.58; 95% CI = [0.42; 0.79]; p < 0.01) and neurosurgical interventions (OR = 0.59; 95% CI = [0.42; 0.82]; p < 0.01) compared to VKAs. Moreover, patients on DOACs experienced shorter length of stay in the hospital than those on VKAs (OR = -0.42; 95% CI = [−0.78; −0.07]; p = 0.02).We found a lower risk of immediate ICH and surgical interventions as well as a shorter hospital stay in patients receiving DOACs compared to VKA users before the head injury. [ABSTRACT FROM AUTHOR]

This paper proposes a new transformerless buck‐boost converter with an extended voltage conversion ratio. This converter has semi‐quadratic voltage gain, which provides more gain with lower duty cycles. This converter has a simple structure and easy implementation, which reduces the cost and increases efficiency. The proposed converter operates in continuous conduction mode and provides two operation modes by turning on and off the switches. The suggested converter has continuous input current and low input current ripple, which is important when utilizing renewable energy sources. The calculation of the proposed converter includes ideal and practical voltage gain, current calculations, voltage stresses of the switches and diodes, current stress of the switches, parameter design, efficiency, and a brief analysis of discontinuous conduction mode and boundary conditions. The proposed converter provides efficiency of about 93.1% in boost mode and 92.14% in buck mode at 50 W output power. The suggested converter varies the input voltage from 20 to 48 V in boost mode and changes the input voltage from 20 to 10.4 V in buck mode. Finally, a laboratory prototype has been built to prove and evaluate the simulation results and theoretical analysis of the proposed converter. [ABSTRACT FROM AUTHOR]

In this study, to solve total harmonic distortion (THD) and voltage stress on switches, challenges have been made by presenting a new multi‐level inverter (MLI). The proposed topology can operate with both symmetric and asymmetric sources. The proposed topology in symmetric and asymmetric mode with 18 switches can produce 17 and 49 voltage levels, respectively, with THD values of 4.14% and 1.45%, which passes the IEEE harmonic standard. The main advantage of the proposed topology is reducing the number of circuit devices, which reduces the price, volume, and complexity of the circuit by reducing the number of circuit devices. The proposed topology reduces the THD, the number of power electronics components, and voltage stress by increasing the output levels. The proposed topology is compared with other topologies and the advantage of the proposed topology is shown in terms of the number of switches and drivers. In addition, the proposed topology is compared in terms of the cost function. The power losses based on the thermal model of the proposed topology have been analysed and simulated. Simulation and experimental results are presented for different scenarios such as load type, load changes, and modulation index changes to validate the proposed topology. [ABSTRACT FROM AUTHOR]

Introduction: Stroke is a leading cause of morbidity and mortality in the USA and has implications on the financial health of patients, families, and healthcare systems. The objective of this study aimed to determine the economic perspective of stroke on the national healthcare system for the past 2 decades. Methods: This retrospective study of inpatient subjects from 2000 to 2020 with stroke was collected from the Healthcare Cost and Utilization Project (HCUP). We queried patients admitted primarily for ischemic or hemorrhagic stroke. Patients were evaluated for demographics, length of stay (LOS), mortality, and hospital charges. Statistical Z-testing with a significance of p < 0.05 was conducted for the analysis. Results: During the study period, 12,158,747 stroke subjects were studied, with 51.9% female and a mean age of 70.08 (±0.16) years old. The mean rate of stroke discharges per 100,000 persons was 187.71 (±3.44), decreasing from 200 to 193 during the study (p = 0.16). The mean percentage of deaths was 8.78% (±0.17), which decreased from 10.96% to 6.81% (p = 0.00). The mean LOS was 6.28 days (±0.08), which increased from 6.70 to 7.15 (p = 0.00). During the study period, the aggregated national bill was USD 725 billion. The mean hospital charges per patient were USD 57,178 (±1,504), increasing from USD 19,647 to USD 121,765 per person during the study period (p = 0.00), while mean hospital costs per stay were USD 15,781 (±330). These data closely conform to an exponential growth pattern, and forecasting per patient charges for the next 10 years demonstrates a cost of USD 287,836 by 2030. Conclusions: Our data show that the rate and mortality of stroke have decreased, but its charges and costs are increasing. The improvement in outcomes could be multifactorial such as establishment of comprehensive stroke centers and evolving treatment modalities. Ironically, the charges per patient increased more than sixfold with a national bill almost equal to the annual Medicare budget. Thus, the significance of preventive medicine, such as controlling hypertension, diabetes, and smoking cessation, cannot be understated. With such a dramatically increasing financial burden, improvements in mitigating risk factors, educational programs, and access to care may be a more cost-effective option. [ABSTRACT FROM AUTHOR]

Today, multilevel inverters are widely utilized in various applications. Reducing the number of components in the design of these converters is one of the crucial goals so that they have less volume and cost. This paper presents a single‐source structure for a multilevel switched‐capacitor inverter with voltage boost capability. The proposed structure can generate 25 sinusoidal‐like step voltage levels with a six times amplitude increase compared to the input. This converter uses only one direct current (DC) power source, 14 switches, and four capacitors. The nearest level control switching method has been used to control the converter, create voltage levels, and select the switching modes. A comprehensive comparison has been made with other recently presented structures to demonstrate the efficiency of the proposed structure. The advantages of the proposed structure include using only one DC voltage source, the ability to increase the output voltage six times compared to the input, the use of fewer power electronics components compared to the number of voltage levels, proper efficiency, self‐balancing of capacitors, and as a result, the lower cost. The performance accuracy of the proposed converter has been simulated in the MATLAB Simulink environment and then evaluated by a laboratory prototype. [ABSTRACT FROM AUTHOR]

Summary Multilevel inverters are known as essential converters in renewable sources. First, in this paper, a new submodule is presented, and based on it, a new sub‐multilevel inverter is presented. The proposed sub‐multilevel inverter consists of several unidirectional and bidirectional switches and DC voltage sources. Then, the generalized topology, developed in two modular and cascaded modes, is presented to increase production levels. The proposed submodules are connected in series in the modular topology, increasing production levels. The proposed topology to produce the maximum output levels has the minimum number of IGBTs, drivers, DC voltage sources, etc. Mathematical analyses for conduction and switching losses are provided, and mathematical analyses for the number of devices and voltage across the switches are also presented. In addition to the mathematical analysis of losses, the simulation results are also presented. A general comparison of proposed topology components is presented to demonstrate their advantages. This comparison shows that the proposed topology has the minimum number of power electronic devices. In this paper, nearest level modulation is used to control the proposed topology. The simulation and experimental results of the proposed sub‐multilevel verify the performance of the proposed topology. [ABSTRACT FROM AUTHOR]

This paper presents a non‐isolated single‐switch ultra‐high step‐up (UHSU) DC–DC converter with a three‐winding coupled inductor (CI) which is utilized to achieve ultra‐high voltage gain with a small amount of duty cycle leading to low conduction losses of the power switch and higher efficiency. The voltage gain of the suggested UHSU converter is adjusted by two methods: the duty cycle of the power switch and the three‐winding CI turn ratio, therefore enhancing the design flexibility of the suggested converter. Due to the utilization of the passive clamp circuit in the structure of the proposed converter, it is possible to select a power switch with low voltage rated and small ON‐state resistance, further enhancing the converter efficiency. The operation modes are discussed in detail and to clarify the salient features of the proposed converter, a comparison with other configurations is provided. Finally, to accredit the performance of the proposed converter, a 150‐W laboratory archetype with an input and output voltage of 20 and 300 V, respectively, at 50 kHz switching frequency is fabricated. [ABSTRACT FROM AUTHOR]