Research on fast solid state DC breaker based on a natural current zero-crossing point

The DC fault characteristics of voltage source converter based high voltage direct current (VSC-HVDC) systems are analyzed in this paper. The phenomenon whereby the capacitor on DC side discharges quickly during a DC fault contributes to a large short-circuit fault current. Neither traditional DC breakers nor DC switches can cut off the fault current under this condition. A fast solid state DC breaker design method is proposed in this paper. This method is based on the fault current characteristics of the inverter in multi-terminal HVDC systems (MTDC), where a fault current appears at the natural zero-crossing point near the inverter. At this point, by coordinating the AC breakers near the rectifier, the DC breaker could reliably cut off the DC fault current and protect the system. A detailed model for this fast solid state DC breaker and its operation sequence are studied, based on this design method. Simulations modeling a five-terminal meshed DC grid and a fast DC breaker were carried out with PSCAD/EMTDC using this design method. The results from the simulations confirmed the validity of the design method

Psychometric properties of the Chinese version of the preoperative assessment of readiness tool among surgical patients

BackgroundThe evaluation of the surgical readiness of patients plays an important role in clinical care. Preoperative readiness assessment is needed to identify the inadequacy among surgical patients, which provides guide for interventions to improve patients’ preoperative readiness. However, there is a paucity of high-level, quality tool that evaluate surgical readiness of patients in China. The purpose of this study is to translate the Preoperative Assessment of Readiness Tool (PART) into Chinese and determine the reliability and validity of the Chinese version in the population of surgical patients.MethodsUsing a standard translation-backward method, the original English version of PART was translated into Chinese. A convenient sampling of 210 surgical patients was recruited from 6 hospitals in Zhejiang Province to test the psychometric properties of this scale including internal consistency, split-half reliability, content validity, structure validity, and floor/ceiling effect.ResultsA total of 194 patients (92%) completed questionnaires. The Chinese version of PART achieved Cronbach’s alphas 0.948 and McDonald’s omega coefficient 0.947, respectively, for the full scale. The estimated odd-even split-half reliability was 0.959. The scale-level content validity index was 0.867, and the items content validity index ranged from 0.83 to 1.0.The output of confirmatory factor analysis (CFA) revealed a two-factor model (χ2 = 510.96; df = 86; p < 0.001; root mean square error approximation = 0.08) with no floor/ceiling effect.ConclusionThe Chinese version of PART demonstrated acceptable reliability and validity among surgical patients. It can be used to evaluate patients’ preoperative preparation and help health professionals provide proper preoperative support

Review of Recently Progress on Neural Electronics and Memcomputing Applications in Intrinsic SiOx-Based Resistive Switching Memory

In this chapter, we focus on the recent process on memcomputing (memristor + computing) in intrinsic SiOx-based resistive switching memory (ReRAM or called memristor). In the first section of the chapter, we investigate neuromorphic computing by mimicking the synaptic behaviors in integrating one-diode and one-resistive switching element (1D-1R) architecture. The power consumption can be minimized further in synaptic functions because sneak-path current has been suppressed and the capability for spike-induced synaptic behaviors has been demonstrated, representing critical milestones and achievements for the application of conventional SiOx-based materials in future advanced neuromorphic computing. In the next section of chapter, we will discuss an implementation technique of implication operations for logic-in-memory computation by using a SiOx-based memristor. The implication function and its truth table have been implemented with the unipolar or nonpolar operation scheme. Furthermore, a circuit with 1D-1R architecture with a 4 × 4 crossbar array has been demonstrated, which realizes the functionality of a one-bit full adder as same as CMOS logic circuits with lower design area requirement. This chapter suggests that a simple, robust approach to realize memcomputing chips is quite compatible with large-scale CMOS manufacturing technology by using an intrinsic SiOx-based memristor

Development and Validation of a Risk Prediction Model of Post-stroke Acute Kidney Injury

Background Acute kidney injury (AKI) is a common and serious complication that is closely correlated to a poor short-term or long-term prognosis in stroke patients. Therefore, it is necessary to develop a specific AKI screening tool to early identify patients at high risk of AKI. Objective To construct and verify a risk prediction model of post-stroke AKI and to develop a simple post-stroke AKI risk assessment scale. Methods Stroke inpatients with complete medical records were selected from the Second Affiliated Hospital Zhejiang University School of Medicine by use of convenience sampling, including 760 from neurology department treated during January to September 2021 (model group, 140 with AKI, and 620 without), and 310 treated during October to December 2021 (validation group, 53 with AKI and 257 without). Multivariate Logistic regression was used to identify factors associated with post-stroke AKI, then these factors were used to develop a risk prediction model. The Hosmer-Lemeshow test and receiver operating characteristic analysis were performed to assess the accuracy of fit and prediction value of the model, respectively. Then the model was verified in validation group, and based on the validation results, a simple post-stroke AKI risk assessment scale was developed. Results The prevalence of post-stroke AKI in the model group was 18.42% (P<0.05). Multivariate Logistic regression analysis showed that sex, history of hypertension, NIHSS score, history of use of loop diuretics, history of mechanical thrombectomy, serum levels of β2-MG, urea nitrogen, and sCysC were independently associated with post-stroke AKI (P<0.05). The post-stroke AKI risk prediction model constructed is y=1/ (1+e-a), in which a=-4.047+1.222× male + 1.386 × hypertension history + 1.716 × NIHSS score + 1.098 ×history of use of loop diuretics + 0.830 × mechanical thrombectomy history + 1.739 × β2-MG+1.202 × urea nitrogen + 2.160 × sCysC. The fit of the model was χ2=6.523, P=0.367. The AUC of the model for predicting post-stroke AKI in model group was 0.916 〔95%CI (0.891, 0.940) 〕, with 0.857 sensitivity, 0.832 specificity, and 0.689 Youden index when the optimal cut-off value was chosen as 12.8%. And the AUC of the model in predicting post-stroke AKI in the verification group was 0.906 〔95%CI (0.853, 0.960) 〕. The coefficients (β) derived from multivariate Logistic regression were rounded to the nearest integral value and weighted, then used to compile a simple scale with a total points of 11, whose AUC in predicting post-stroke AKI risk was 0.900〔95%CI (0.843, 0.957), P<0.001〕when the optimal cut-off value was determined as 4, and the accuracy rate of which in practical applications was 88.39%. Conclusion Our risk prediction model could effectively predict the risk of post-stroke AKI with high sensitivity and specificity, and the risk assessment scale compiled based on the model is a simple, feasible, objective, and quantitative tool for identifying high-risk patients, and the assessment result may be a reference for doctors and nurses to take interventions to early prevent AKI in stroke patients

CIRED Workshop -Lisbon U UT TI IL LI IZ ZI IN NG G L LO OC CA AL L R RE ES SO OU UR RC CE ES S T TO O P PA AR RT TI IC CI IP PA AT TE E I IN N P PO OW WE ER R B BA AL LA AN NC CE E: : A A C CO ON NC CE EP PT T A AN ND D I IT TS S R RE EA AL LI IZ ZA AT TI

ABSTRAC

Development and validation of fall risk perception scale for patients with Parkinson’s disease

BackgroundPerception assessment plays an important role in fall risk awareness and fall prevention. Parkinson’s disease patients with motor dysfunction are at high risk of falling. Currently, no instrument has been explicitly crafted to assess the risk perception of fall in PD patients. The purpose of this study was to develop and validate the fall risk perception scale for PD patients (FRPS-PD), providing healthcare professionals with a effective assessment tool to enhance proactive fall prevention initiatives.MethodBased on the Proactive Health theory and Risk Perception Attitude (RPA) Framework, the questionnaire was developed through literature review, semi-structure interview, expert consultation and pilot testing. A total of 428 patients with PD from Grade A tertiary hospitals in Shanghai, Hangzhou and Anhui from January 2023 to July 2023 were recruited. The items and dimensions in the scale were explored and confirmed using item-analysis, content validity, exploratory factor analytical (EFA), confirmatory factor analytical (CFA), internal consistency and test–retest reliability analysis.ResultsA total of 16-items, 2-dimensions structure were identified, including 12 items of risk perception and 4 items of self-efficacy dimension. The cumulative variance of EFA model was 73.669%, further CFA showed that acceptable model fit (χ2/df = 2.226, RMSEA = 0.074, NF = 0.928, TLI = 0.951, CFI = 0.959, GFI = 0.887 and AGFI = 0.848). The content validity index was 0.956. The reliability of the scale was 0.952 using Cronbach’s α coefficient method. The test–retest reliability was 0.944.ConclusionThe FRPS-PD is a valid and reliable measurement for evaluating fall risk perception level for individuals with PD in mainland China

A three-terminal HVDC system to bundle wind farms with conventional power plants

There is a concern over large, fluctuating wind power injected into a power system, which could affect stability, frequency and power quality of the power system. A method of using three-terminal HVDC system to bundle large scale wind farms with conventional power plants is proposed to overcome this problem. The wind power fluctuation is canceled by regulating the power from the conventional power plants. Topology of the scheme is described. A control strategy particularly suitable to cope with wind power fluctuation is designed. Novel fault ride through mechanisms are designed to enable safe operation of the system. Simulations using PSCAD/EMTDC verify the successful operation of the system during starting-up, steady state, wind power variations and faults. The proposed scheme provides a novel way to deal with the integration of large scale wind power

Data_Sheet_1_Development and validation of fall risk perception scale for patients with Parkinson’s disease.doc

BackgroundPerception assessment plays an important role in fall risk awareness and fall prevention. Parkinson’s disease patients with motor dysfunction are at high risk of falling. Currently, no instrument has been explicitly crafted to assess the risk perception of fall in PD patients. The purpose of this study was to develop and validate the fall risk perception scale for PD patients (FRPS-PD), providing healthcare professionals with a effective assessment tool to enhance proactive fall prevention initiatives.MethodBased on the Proactive Health theory and Risk Perception Attitude (RPA) Framework, the questionnaire was developed through literature review, semi-structure interview, expert consultation and pilot testing. A total of 428 patients with PD from Grade A tertiary hospitals in Shanghai, Hangzhou and Anhui from January 2023 to July 2023 were recruited. The items and dimensions in the scale were explored and confirmed using item-analysis, content validity, exploratory factor analytical (EFA), confirmatory factor analytical (CFA), internal consistency and test–retest reliability analysis.ResultsA total of 16-items, 2-dimensions structure were identified, including 12 items of risk perception and 4 items of self-efficacy dimension. The cumulative variance of EFA model was 73.669%, further CFA showed that acceptable model fit (χ2/df = 2.226, RMSEA = 0.074, NF = 0.928, TLI = 0.951, CFI = 0.959, GFI = 0.887 and AGFI = 0.848). The content validity index was 0.956. The reliability of the scale was 0.952 using Cronbach’s α coefficient method. The test–retest reliability was 0.944.ConclusionThe FRPS-PD is a valid and reliable measurement for evaluating fall risk perception level for individuals with PD in mainland China.</p