Modeling of Supercritical Co2 Shell-and-Tube Heat Exchangers Under Extreme Conditions. Part 1: Correlation Development

High-temperature supercritical CO2 Brayton cycles are promising possibilities for future stationary power generation and hybrid electric propulsion applications. Heat exchangers are critical components in supercritical CO2 thermal cycles and require accurate correlations and comprehensive performance modeling under extreme temperatures and pressures. In this paper (part I), new Colburn and friction factor correlations are developed to quantify shell-side heat transfer and friction characteristics of flow within heat exchangers in the shell-and-tube configuration. Using experimental and CFD data sets from existing literature, multivariate regression analysis is conducted to achieve correlations that capture the effect of multiple critical geometric parameters. These correlations offer superior accuracy and versatility as compared to previous studies and predict the thermohydraulic performance of about 90% of the existing experimental and CFD data within ±15%. Supplementary thermohydraulic performance data is acquired from CFD simulations with sCO2 as working fluid to validate the developed correlations and demonstrate its capability to be applied to sCO2 heat exchangers.

A Predictive Model of Pandemic Disaster Fear Caused by Coronavirus (COVID-19): Implications for Decision-Makers

This paper presents quantitative research results regarding a predictive model of pandemic disaster fear caused by the coronavirus disease (COVİD-19). The aim of this paper was to establish the level and impact of certain demographic and socioeconomic characteristics on pandemic disaster fear caused by the coronavirus (COVID-19). The research was conducted using a questionnaire that was provided and then collected online for 1226 respondents during May 2021. A closed, five-point Likert scale was used to create the structured questionnaire. The first section of the questionnaire included research questions about the participants’ socioeconomic and demographic characteristics, while the second section included issue questions about fear caused by COVID-19. The results of multivariate regression analyses showed the most important predictor for fear of COVID-19 to be gender, followed by age and education level. Furthermore, the results of t-tests showed statistically significant differences between men and women in terms of different aspects of pandemic disaster fear caused by the coronavirus disease. Our results have several significant public health implications. Women who were more educated and knowledgeable, married, and older, reported a greater fear of the outbreak at various levels. Decision-makers can use these findings to identify better strategic opportunities for pandemic disaster risk management.

Improved ROSC rates in out-of-hospital cardiac arrest patients after introduction of a text message alert system for trained volunteers

Objective To evaluate whether a text message (TM) alert system for trained volunteers contributed to early cardiopulmonary resuscitation, the use of automated external defibrillators (AEDs), return of spontaneous circulation (ROSC) and survival in out-of-hospital cardiac arrest (OHCA) patients in a region with above-average survival rates. Design Data on all OHCA patients in 2012 (non-TM group) were compared with those of all OHCA patients in 2018 (TM group). The association of the presence of a TM alert system with ROSC and survival was assessed with multivariate regression analyses. Results TM responders reached 42 OHCA patients (15.9%) earlier than the first responders or ambulance. They connected 31 of these 42 OHCA patients (73.8%) to an AED before the ambulance arrived, leading to a higher percentage of AEDs being attached in 2018 compared to the 2012 non-TM group (55% vs 46%, p = 0.03). ROSC was achieved more often in the TM group (61.0% vs 29.4%, p < 0.01). Three-month and 1‑year survival did not differ significantly between the two groups (29.3% vs 24.3%, p = 0.19, and 25.9% vs 23.5%, p = 0.51). Multivariate regression analyses confirmed the positive association of ROSC with the TM alert system (odds ratio 1.49, 95% confidence interval 1.02‑2.19, p = 0.04). Conclusion A TM alert system seems to improve the chain of survival; because TM responders reached patients early, AEDs were attached more often and more OHCA patients achieved ROSC. However, the introduction of a TM alert system was not associated with improved 3‑month or 1‑year survival in a region with above-average survival rates.

Association between blood pressure and the risk of biopsy-induced endobronchial hemorrhage during bronchoscopy

Background Hemorrhage is one of the most common complications of bronchoscopy. Although several hemorrhage risk factors have been proposed, it remains unclear whether blood pressure affects the onset of biopsy-induced endobronchial hemorrhage. Methods We conducted a retrospective cohort study of 643 consecutive adults with lung cancer over an approximately 4-year period (from January 2014 to February 2018) at a large tertiary care hospital. Patients were divided into the hemorrhage group and the non-hemorrhage group based on endobronchial biopsy (EBB) findings. The association between systolic pressure (SP), diastolic pressure (DP), mean arterial pressure (MAP), pulse pressure (PP), PP to DP ratio (PP/DP) and the risk of EBB-induced hemorrhage was evaluated using multivariate regression analysis and smooth curve fitting adjusted for potential confounding factors. Results The EBB-induced bleeding incidence was 37.8% (243/643) in our cohort. An independent association was found between PP/PD and the EBB-induced hemorrhage risk (per 1 SD, adjusted odds ratio, 0.788; 95% confidence interval, 0.653-0.951). The multivariate regression analysis performed using quartiles of PP/DP revealed that lower level of PP/DP ratio was related to a higher risk of EBB-induced hemorrhage (P for trend <0.05) after adjustment for potential confounders. However, no association was observed between SP, DP, MAP, PP and EBB-induced hemorrhage. Conclusions Low PP/DP was the independent risk factor for biopsy-induced endobronchial hemorrhage during bronchoscopy in patients with lung cancer.

Assessment of factors affecting flicker ERGs recorded with RETeval from data obtained from health checkup screening

The purpose of this study was to determine the ocular, sex- and age-specific, anthropometric, and hematologic factors that affect the implicit times and amplitudes of the flicker ERGs recorded with the RETeval system from individuals 40- to 89-years-of-age. Flicker ERGs were recorded with the RETeval system from 330 individuals who had normal fundus and OCT images. Univariate and multivariate regression analyses were performed to identify factors associated with the implicit times and amplitudes of the RETeval flicker ERGs. Univariate regression analyses showed significant correlations between the implicit times and the BCVA, age, axial length, blood sugar level, and BUN in both eyes. Multivariate regression analyses identified age and axial length as two independent factors that were significantly correlated with the implicit times of the RETeval flicker ERGs. Univariate regression analyses also showed significant correlations between the amplitudes and age, platelet count, HDL level, and creatinine level in both eyes. However, smoking habits, body mass index, and blood pressure were not correlated with the RETeval flicker ERGs. We conclude that age and some ophthalmologic and hematologic findings except for anthropometric findings were suggested to significantly affect the measurements of the RETeval flicker ERGs.

Are politically engaged citizens more democratic? A glimpse from Brazil

A significant part of the Western literature on democracy assumes that political participation leads to citizens being more committed to democratic values. However, we do not know to what extent this is true in young democracies with an authoritarian tradition. Hence, this article aims to examine whether politically engaged Brazilians are more democratic. To do so, we analyzed whether there is any association between political participation, support for democracy, and democracy relativization through multivariate regression models. Our database comprises a representative sample of 2417 interviews with the electorate of São Paulo in 2019. The results show a statistically significant association between unconventional political participation and support for democracy. General political participation is associated with non-relativization of democracy only, showing a limited relationship between support for democracy and participation. Other variables, such as political interest, political knowledge, and interpersonal trust, are also associated with higher support for democracy.

Multiple and quantitative measurements using computed tomography images reveal the factors associated with chronic subdural hematoma recurrence

Objective: The aim of this retrospective single–center study was to quantitatively assess chronic subdural hematomas (CSDHs), reveal the correlations between multiple and quantitative values calculated from computed tomography images, and determine the risk factors for CSDH recurrence. Methods: We enrolled 225 patients who underwent 304 burr-hole surgeries between April 2005 and October 2021 at Otemae Hospital. Patients′ medical records and quantitative values including preoperative CSDH volume (ml), thickness (mm), computed tomography values (CTV), postoperative CSDH volume (ml), and air volume (ml) were evaluated. The locations of CSDH thickness and burr holes were also assessed quantitatively using Montreal Neurological Institute coordinates. Univariate and multivariate regression analyses and receiver operating characteristic (ROC) analyses were performed. Results: Thirty–seven patients (12%) showed CSDH recurrence requiring reoperation. Preoperative CSDH volume was positively correlated with age, preoperative CSDH thickness, CTV, postoperative CSDH volume, and air volume. Univariate Cox proportional hazards regression analysis showed that age, preoperative CSDH volume, Glasgow Coma Scale score (3–14), postoperative hemiplegia, and gait disturbance were risk factors for recurrence requiring reoperation, and a higher CTV (hazard ratio 0.95, 95% confidence interval 0.91–0.99) was associated with a lower risk of recurrence requiring reoperation. Only preoperative CSDH volume was a significant risk factor for recurrence requiring reoperation in multivariate regression analyses. The postoperative air volume and locations of CSDH thickness and burr hole had no influence on recurrence requiring reoperation. ROC curve analysis revealed that the optimal preoperative CSDH volume cut-off value as a predictor was 155 ml, the thickness was approximately 36.3 mm calculated from a regression line. Conclusions: A larger and more hypodense CSDH has a high risk of recurrence requiring reoperation. Residual air volume after surgery and locations of CSDH and burr hole had no influence on recurrence requiring reoperation.

Risk factors for postanesthetic emergence delirium in adults: A systematic review and meta-analysis

Review question / Objective: Patientor population: patients with emergence delirium; Exposure: anaesthesia and surgery; Control: patients with no emergence delirium; Outcome: risk factors; Study design: meta-analysis. Eligibility criteria: To ensure the quality of this meta-analysis, inclusion criteria was decided before we carried out the search. These criteria were: (a) Original researches that carried out in observational studies. (b)Adult patients who were extubated and recovered at PACU, operation room, or intensive care unit (ICU) after surgeries and anesthesia (including general and neuraxial anesthesia, peripheral nerve blocks and sedation). (c) Risk factors for delirium must be assessed with odds ratio (OR) with 95% confidence interval (CI). Researches must present the results of multivariate regression to be considered eligible for inclusion, since multivariate analysis results shall be used to identify variables eligible for meta-analysis. (d) Full-text available literatures.