bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved cerebral blood flow and hippocampal blood flow in stroke‐free patients after catheter ablation of atrial fibrillation
Authors: Hashimoto Naoaki , Arimoto Takanori , Koyama Kyoko , Kutsuzawa Daisuke , Watanabe Ken , Aita Satoshi , Aono Tomonori , Kobayashi Yuta , Wanezaki Masahiro , Otaki Yoichiro , Kato Shigehiko , Tamura Harutoshi , Nishiyama Satoshi , Takahashi Hiroki , Ohba Makoto , Haga Kazuyuki , Watanabe Tetsu , Watanabe Masafumi
Published: September 2023

Introduction

Atrial fibrillation (AF) is a risk factor for reduced cerebral blood flow (CBF) and cognitive dysfunction, even in stroke‐free patients. We aimed to test the hypothesis that CBF and hippocampal blood flow (HBF), measured with arterial spin labeling magnetic resonance imaging (MRI), improve after catheter ablation of AF to achieve sinus rhythm (SR).

Methods

A total of 84 stroke‐free patients (63.1 ± 9.1 years; paroxysmal AF, n = 50; non‐paroxysmal AF, n = 34) undergoing AF catheter ablation were included. MRI studies were done before, 3 months, and 12 months after the procedure with CBF and HBF measurements.

Results

Baseline CBF and HBF values in 50 paroxysmal AF patients were used as controls. Baseline CBF was higher in patients with paroxysmal AF than with non‐paroxysmal AF (100 ± 32% vs. 86 ± 28%, p = .04). Patients with non‐paroxysmal AF had increased CBF 3 months after AF ablation (86 ± 28% to 99 ± 34%, p = .03). Differences in CBF and HBF were greater in the group with AF restored to SR (p < .01). Both CBF and HBF levels at 12 months were unchanged from the 3 months level. Successful rhythm control by catheter ablation was an independent predictor of an increase in CBF > 17.5%. The Mini‐Mental State Examination score improved after ablation (p = .02).

Conclusion

SR restoration with catheter ablation was associated with improved CBF and HBF at 3 months, maintenance of blood flow, and improved cognitive function at 12 months.
Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving an out‐of‐hospital cardiac arrest
Authors: Thomsen Anna F. , Winkel Bo G. , Golvano Leticia Camino Castrillo , Porta‐Sánchez Andreu , Jøns Christian , Ferro Elisenda , Bertelsen Litten , Vazquez Sara , Bhardwaj Priya , Stampe Niels Kjær , Ortiz‐Perez José T. , Andrea Rut , Engstrøm Thomas , Køber Lars , Vejlstrup Niels , Mont Lluís , Roca‐Luque Ivo , Jacobsen Peter K.
Published: September 2023

Introduction

Prediction of recurrent ventricular arrhythmia (VA) in survivors of an out‐of‐hospital cardiac arrest (OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring assessed with late gadolinium enhancement cardiac magnetic resonance (LGE‐CMR). Our study aims to characterize myocardial scarring as defined by LGE‐CMR in survivors of a VA‐OHCA and investigate its potential role in the risk of new VA events.

Methods

Between 2015 and 2022, a total of 230 VA‐OHCA patients without ST‐segment elevation myocardial infarction had CMR before implantable cardioverter‐defibrillator implantation for secondary prevention at Copenhagen University Hospital, Rigshospitalet, and Hospital Clínic, University of Barcelona, of which n = 170 patients had a conventional (no LGE protocol) CMR and n = 60 patients had LGE‐CMR (including LGE protocol). Scar tissue including core, border zone (BZ) and BZ channels were automatically detected by specialized investigational software in patients with LGE‐CMR. The primary endpoint was recurrent VA.

Results

After exclusion, n = 52 VA‐OHCA patients with LGE‐CMR and a mean left ventricular ejection fraction of 49 ± 16% were included, of which 18 (32%) patients reached the primary endpoint of VA. Patients with recurrent VA in exhibited greater scar mass, core mass, BZ mass, and presence of BZ channels compared with patients without recurrent VA. The presence of BZ channels identified patients with recurrent VA with 67% sensitivity and 85% specificity (area under the ROC curve (AUC) 0.76; 95% CI: 0.63–0.89; p < .001) and was the strongest predictor of the primary endpoint.

Conclusions

The presence of BZ channels was the strongest predictor of recurrent VA in patients with an out of‐hospital cardiac arrest and LGE‐CMR.
Limits of the spatial ventricular gradient and QRST angles in patients with normal electrocardiograms and no known cardiovascular disease stratified by age, sex, and race
Authors: Stabenau Hans F. , Sau Arunashis , Kramer Daniel B. , Peters Nicholas S. , Ng Fu Siong , Waks Jonathan W.
Published: September 2023

Introduction

Measurement of the spatial ventricular gradient (SVG), spatial QRST angles, and other vectorcardiographic measures of myocardial electrical heterogeneity have emerged as novel risk stratification methods for sudden cardiac death and other adverse cardiovascular events. Prior studies of normal limits of these measurements included primarily young, healthy, White volunteers, but normal limits in older patients are unknown. The influence of race and body mass index (BMI) on these measurements is also unclear.

Methods

Normal 12‐lead electrocardiograms (ECGs) from a single center were identified. Patients with abnormal cardiovascular, pulmonary, or renal history (assessed by International Classification of Disease [ICD‐9/ICD‐10] codes) or abnormal cardiovascular imaging were excluded. The SVG and QRST angles were measured and stratified by age, sex, and race. Multivariable linear regression was used to assess the influence of age, BMI, and heart rate (HR) on these measurements.

Results

Among 3292 patients, observed ranges of SVG and QRST angles (peak and mean) differed significantly based on sex, age, and race. Sex differences attenuated with increasing age. Men tended to have larger SVG magnitude (60.4 [46.1–77.8] vs. 52.5 [41.3–65.8] mv*ms, p < .0001) and elevation, and more anterior/negative SVG azimuth (−14.8 [−25.1 to −4.3] vs. 1.3 [−9.8 to 10.5] deg, p < .0001) compared to women. Men also had wider QRST angles. Observed ranges varied significantly with BMI and HR. SVG and QRST angle measurements were robust to different filtering bandwidths and moderate fiducial point annotation errors, but were heavily affected by changes in baseline correction.

Conclusions

Age, sex, race, BMI, and HR significantly affect the range of SVG and QRST angles in patients with normal ECGs and no known cardiovascular disease, and should be accounted for in future studies. An online calculator for prediction of these “normal limits” given demographics is provided at https://bivectors.github.io/gehcalc/.
Direct etching of nano/microscale patterns with both few‐layer graphene and high‐depth graphite structures by the raster STM electric lithography in the ambient conditions
Authors: Yang Ye , Xu Yang
Published: September 2023

The development of raster STM electric lithography has enabled the etching of nano/microscale patterns on both few‐layer graphene (FLG) and high‐depth graphite structures on the bulk HOPG substrates under ambient conditions. This approach utilises a nanoscale probe tip as a machining tool to directly fabricate conductive sample surfaces without the need for resists or masks. Compared to conventional nano/micro machining methods, the capability of ultraaccurate fabrication of nanoscale patterns using this technique is unmatched. The resulting FLG structures exhibit ultrasmooth flat bottoms and uniformly controlled depths ranging from 0.34 to 3.0 nm (less than 10 layers). This work represents a significant advancement as it demonstrates the perfect etching of FLG structures in designated nano/microscale regions using raster STM electric lithography in the constant current mode, which reaches the limitation of top‐down manufacturing techniques. Additionally, raster STM electric lithography in the constant height mode can directly etch high‐depth structures (up to ∼100 nm). The geometric shape and number of layers of the etched graphene structures determined by either local anodic oxidation (LAO) or the electric discharge (ED) mechanism. The LAO mechanism results in less debris and smoother edges compared to the ED mechanism, which is caused by the random electrical discharge between the tip and the sample. The well‐controlled raster STM electric lithography technique is believed to be a promising and facile approach for constructing nano/microscale graphene‐based devices.
Smooth transition moving average models: Estimation, testing, and computation
Authors: Zhang Xinyu , Li Dong
Published: September 2023

The article introduces a new subclass of nonlinear moving average model, called the smooth transition moving average (STMA) model, and studies its probabilistic properties. It is shown that, under some mild conditions, the least squares estimation (LSE) is strongly consistent and asymptotically normal. A powerful score‐based goodness‐of‐fit test for the STMA model is presented. A different parametrization from the classical one is applied to numerically improve the identification and estimation of this model. Simulation studies are conducted to assess the performance of the LSE and the score‐based test in finite samples. The results are illustrated with an application to the weekly exchange rate of the USA Dollar to the British Pound.
The Failure of Roy Bhaskar's Explanatory Critique
Authors: Hannegan William
Published: September 2023

According to Roy Bhaskar, social science can derive values from social facts by a process called “explanatory critique.” Bhaskar offers two different versions of explanatory critique: a belief‐based version and a need‐based version. Both versions are faced with a difficult objection. They seem either to employ an invalid inference or to assume the values that they are attempting to derive. I argue that at least the need‐based version of Bhaskar's explanatory critique falls to the objection, and that the belief‐based version on its own is insufficient. Bhaskar anticipates the objection and offers a defense. I show that his defense is unsuccessful. I also suggest a Baskar‐inspired alternative explanatory critique.
Careless whisper: Political elite discourses activate national identities for far‐right voting preferences
Authors: May Antonia C , Czymara Christian S
Published: September 2023

While exclusionary national identities are widespread among Europeans, relatively few people vote for the far right in most countries. Thus, an exclusionary identity in many cases does not lead to voting for the most nativist types of parties. We explain this empirical puzzle by showing that these identities need to be activated to become behaviourally relevant. To this end, we analyse longitudinal comparative data of over 135,000 individuals across more than 26 years and 26 countries combining different survey programmes and manifesto data. We use latent class analysis to show that over half of respondents hold exclusionary conceptions of nationhood. Moreover, this type of national identity predicts voting far right. Using multi‐level modelling and within‐country estimators, we further demonstrate that this relationship is significantly stronger when a country's political elites across all parties become more exclusionary. Taking the activation hypothesis to the test in a European context, we conclude that the effect of national identity is conditional on its prior activation.
Covariation between oxygen and hydrogen stable isotopes declines along the path from xylem water to wood cellulose across an aridity gradient
Authors: Holloway‐Phillips Meisha , Cernusak Lucas A. , Nelson Daniel B. , Lehmann Marco M. , Tcherkez Guillaume , Kahmen Ansgar
Published: September 2023

Oxygen and hydrogen isotopes of cellulose in plant biology are commonly used to infer environmental conditions, often from time series measurements of tree rings. However, the covariation (or the lack thereof) between δ18O and δ2H in plant cellulose is still poorly understood.

We compared plant water, and leaf and branch cellulose from dominant tree species across an aridity gradient in Northern Australia, to examine how δ18O and δ2H relate to each other and to mean annual precipitation (MAP).

We identified a decline in covariation from xylem to leaf water, and onwards from leaf to branch wood cellulose. Covariation in leaf water isotopic enrichment (Δ) was partially preserved in leaf cellulose but not branch wood cellulose. Furthermore, whilst δ2H was well‐correlated between leaf and branch, there was an offset in δ18O between organs that increased with decreasing MAP.

Our findings strongly suggest that postphotosynthetic isotope exchange with water is more apparent for oxygen isotopes, whereas variable kinetic and nonequilibrium isotope effects add complexity to interpreting metabolic‐induced δ2H patterns. Varying oxygen isotope exchange in wood and leaf cellulose must be accounted for when δ18O is used to reconstruct climatic scenarios. Conversely, comparing δ2H and δ18O patterns may reveal environmentally induced shifts in metabolism.
Case of unicystic ameloblastoma with review of literature
Authors: Dahivelkar Sachinkumar , Mali Shrikant B. , Mahajan Aarti , Prakash Nilima
Published: September 2023

Introduction

Ameloblastoma is one of the most frequent benign odontogenic tumours of the jaw, accounting for approximately 10% of all tumours in the mandible and maxilla. It is a slow‐growing, locally invasive tumour that causes painless swelling of the jaw or maxilla.

Diagnosis

Ameloblastoma is diagnosed through computerised tomography imaging and a biopsy. A biopsy can help distinguish ameloblastoma from other cancers, such as ossifying fibroma, osteomyelitis, giant cell tumour, cystic fibrous dysplasia, myeloma, and sarcoma.

Treatment

Ameloblastoma is best treated with vigorous en bloc excision and concomitant repair. Ameloblastoma therapy has long been plagued by high recurrence rates and extensive tissue abnormalities. Recent molecular findings strongly imply that ameloblastoma patients may benefit from targeted treatment. We offer a case report of unicystic ameloblastoma with a step‐by‐step customised therapeutic plan that prioritises patients’ desire.
Vapour pressure deficit was not a primary limiting factor for gas exchange in an irrigated, mature dryland Aleppo pine forest
Authors: Preisler Yakir , Grünzweig José M. , Ahiman Ori , Amer Madi , Oz Itai , Feng Xue , Muller Jonathan D. , Ruehr Nadine , Rotenberg Eyal , Birami Benjamin , Yakir Dan
Published: September 2023

Climate change is often associated with increasing vapour pressure deficit (VPD) and changes in soil moisture (SM). While atmospheric and soil drying often co‐occur, their differential effects on plant functioning and productivity remain uncertain. We investigated the divergent effects and underlying mechanisms of soil and atmospheric drought based on continuous, in situ measurements of branch gas exchange with automated chambers in a mature semiarid Aleppo pine forest. We investigated the response of control trees exposed to combined soil‒atmospheric drought (low SM, high VPD) during the rainless Mediterranean summer and that of trees experimentally unconstrained by soil dryness (high SM; using supplementary dry season water supply) but subjected to atmospheric drought (high VPD). During the seasonal dry period, branch conductance (gbr), transpiration rate (E) and net photosynthesis (Anet) decreased in low‐SM trees but greatly increased in high‐SM trees. The response of E and gbr to the massive rise in VPD (to 7 kPa) was negative in low‐SM trees and positive in high‐SM trees. These observations were consistent with predictions based on a simple plant hydraulic model showing the importance of plant water potential in the gbr and E response to VPD. These results demonstrate that avoiding drought on the supply side (SM) and relying on plant hydraulic regulation constrains the effects of atmospheric drought (VPD) as a stressor on canopy gas exchange in mature pine trees under field conditions.
Should price cannibalization be avoided or embraced? A multimethod investigation
Authors: Mehrdar Atabak , Li Ting
Published: September 2023

This paper proposes price cannibalization as a growth strategy despite prior findings that suggests avoiding it. We focus on a multiclass, capacity‐constrained pricing problem in which each of the product classes has a price range. Specifically, we examine the effects of price range overlaps and introduce it as a revenue‐maximizing pricing strategy. Price cannibalization happens when sales in some product classes decrease due to the existence of overlaps between the price ranges. We employ a multimethod approach. First, we define a Markov decision problem to obtain the revenue‐maximizing strategy in a two‐class sales scenario. We show that price range overlaps are part of the optimal strategy. Second, we collect multichannel data from a European storage company to examine how price range overlaps impact a customer's purchase decisions. The results show that the existence of price range overlaps leads to cannibalization, but increases spending and improves conversion. Finally, we use simulations to compare several pricing strategies and demonstrate the long‐term effects of using price range overlaps in pricing algorithms in complex situations. Our findings suggest that using price range overlaps, though leads to cannibalization, actually helps companies avoid spoilage and early sellouts, leading to better capacity utilization and higher revenue.
Managerial flexibility, capacity investment, and inventory levels
Authors: Aral Karca D. , Giambona Erasmo , Van Wassenhove Luk N.
Published: September 2023

We study the effect of managerial time horizon on two key operations decisions: inventory levels and capacity investment. For identification, we exploit a quasi‐natural experiment provided by the staggered adoption of constituency statutes, which alleviate managerial short‐termism by providing legal protection to executives adopting a long‐term approach in their corporate decisions. Using a staggered difference‐in‐differences design, we find that, after the reforms, firms incorporated in constituency states (treated firms) increased inventory and capacity investment by 5.2% and 15.4%, respectively, relative to firms not incorporated in constituency states (control firms). We also find that these increases are gradual and persist over time, suggesting that they are structural in nature. We further show that the effect of constituency statutes on inventory levels and capacity investment are stronger for firms with ex ante higher level of managerial short‐termism, such as firms with low institutional ownership. Performance also increases relatively more for affected firms with higher ex ante managerial short‐termism. Our results pass a battery of robustness and validity tests. Interestingly, while constituency statutes are intended to protect executives from short‐term oriented shareholder sanctions, our findings suggest that these statutes ultimately benefited not only executives, but also potentially the long‐term interest of shareholders. Even in the absence of regulation, executives facing short‐term pressure could intensify communication efforts with shareholders on how specific operational decisions and investments would be beneficial to the company. Notably, executives could use various media channels to help shape retail investors’ attitude toward operational investments that may create future value.
Fluorescence‐activated multi‐organelle mapping of subcellular plant hormone distribution
Authors: Skalický Vladimír , Antoniadi Ioanna , Pěnčík Aleš , Chamrád Ivo , Lenobel René , Kubeš Martin F. , Zatloukal Marek , Žukauskaitė Asta , Strnad Miroslav , Ljung Karin , Novák Ondřej
Published: September 2023

Auxins and cytokinins are two major families of phytohormones that control most aspects of plant growth, development and plasticity. Their distribution in plants has been described, but the importance of cell‐ and subcellular‐type specific phytohormone homeostasis remains undefined. Herein, we revealed auxin and cytokinin distribution maps showing their different organelle‐specific allocations within the Arabidopsis plant cell. To do so, we have developed Fluorescence‐Activated multi‐Organelle Sorting (FAmOS), an innovative subcellular fractionation technique based on flow cytometric principles. FAmOS allows the simultaneous sorting of four differently labelled organelles based on their individual light scatter and fluorescence parameters while ensuring hormone metabolic stability. Our data showed different subcellular distribution of auxin and cytokinins, revealing the formation of phytohormone gradients that have been suggested by the subcellular localization of auxin and cytokinin transporters, receptors and metabolic enzymes. Both hormones showed enrichment in vacuoles, while cytokinins were also accumulated in the endoplasmic reticulum.
Platelet membrane‐derived microparticles may be biomarkers in patients with hepatocellular carcinoma and can promote the invasion and metastasis of hepatoma carcinoma cells
Authors: Li Xiaofei , Ma Yiming , Liu Chengdi , Pu Fei , Zhang Yuan , Wang Deqing
Published: September 2023

Background

Platelet membrane‐derived microparticles (PMPs) released by apheresis platelets (APs) during storage are involved in immunomodulatory and tumor processes. However, few studies have emphasized the relationship between PMPs and hepatocellular carcinoma (HCC).

Methods

Enzyme‐linked immunosorbent assay (ELISA) was used to detect PMPs in the plasma of HCC patients and healthy individuals. ELISA and flow cytometry were separately applied to analyze the variation in PMPs from APs prepared after 0, 3, 5, and 7 days of storage. Transwell was used to demonstrate the effects of PMPs on the invasion and migration of HCC cells. HCC‐related indicators and invasion and migration‐related markers were detected in vivo.

Results

We found the amount of PMPs was significantly increased in HCC patients. There was also a significant difference in the amount of PMPs in APs with prolonged storage time. Further, the PMPs in D5 promoted the invasion and migration of HepG2 and Huh7 cells. Transcriptomics revealed striking differences in the expression of many tumor metastasis associated genes with PMPs treatment. PMPs promoted tumor growth and weight loss in HCC‐bearing mice, and Western blot results showed that invasion and migration‐related indicators also increase.

Conclusion

The content of PMPs in the plasma of HCC patients increases, and it can also promote the invasion and migration of HCC.
A Machine Learning Framework for Length of Stay Minimization in Healthcare Emergency Department
Authors: Asuquo Daniel , Umoren Imeh , Osang Francis , Attai Kingsley
Published: September 2023

The emergency departments (EDs) in most hospitals, especially in middle-and-low-income countries, need techniques for minimizing the waiting time of patients. The application and utilization of appropriate methods can enhance the number of patients treated, improve patients’ satisfaction, reduce healthcare costs, and lower morbidity and mortality rates which are often associated with poor healthcare facilities, overcrowding, and low availability of healthcare professionals.  Modeling the length of stay (LOS) of patients in healthcare systems is a challenge that must be addressed for sound decision-making regarding capacity planning and resource allocation. This paper presents a machine learning (ML) framework for predicting a patient’s LOS within the ED. A study of the services in the ED of a tertiary healthcare facility in Uyo, Nigeria was conducted to gain insights into its operational procedures and evaluate the impact of certain parameters on LOS. Then, a computer simulation of the system was performed in R programming language using data obtained from records in the hospital. Finally, the performance of four ML classifiers involved in patients’ LOS prediction: Classification and Regression Tree (CART), Random Forest (RF), K-Nearest Neighbour (K-NN), and Support Vector Machine (SVM), were evaluated and results indicate that SVM outperforms others with the highest coefficient of determination (R2) score of 0.986984 and least mean square error (MSE) value of 0.358594. The result demonstrates the capability of ML techniques to effectively assess the performance of healthcare systems and accurately predict patients’ LOS to mitigate the low physician-patient ratio and improve throughput.
Numerical Computation of Williamson Hybrid Nanofluid Flow Over the Curved Surfaces With Effects of Thermal Radiation
Authors: G Iyyappan , Govindaraj N. , Singh A. K.
Published: September 2023

The current investigation is based on Williamson's features of a hybrid nanofluid flow over a curved surface made mixture of silver (Ag) and titanium dioxide (TiO2) with engine oil. Under the presumption of a low magnetic Reynolds number, a constant homogenous magnetic field is applied. Consideration is given to the ramping temperature and the time-varying surface concentration. Thermal absorption and first-order consistent chemical reaction are also taken into account. To create a hybrid nanofluid, silver (Ag), and titanium nanoparticles are dispersed in a base fluid made of water and engine oil. Quasi-linearization technique and Finite difference scheme are employed on the nondimensional partial differential equations. All physical parameters of practical importance, such as velocity, temperature, and concentration profile are analyzed and provided in tables and graphs along with the impact of physical parameters. As the Williamson parameter (W) increases, the surface velocity of the steep plate decreases. Also, as the parameter temperature ratio of Nt and Rd increases, the forces opposing the flow field reduce the friction force, and the thermal field increases with temperature effects.
Numerical Study on Heat Transfer and Pressure Loss Characteristics of Swirl Cooling in Elliptical Tubes With Tangential Jet Inlets
Authors: Li Fei , Xiong Chenglan , Rao Yu , Luan Yong , Weigand Bernhard
Published: September 2023

The paper presents a numerical study of the heat transfer, pressure loss, and flow characteristics of swirl cooling in elliptical tubes, which are compared to the counterpart of swirl cooling in a circular tube with a diameter of D = 50.0 mm under equal passage Reynolds numbers and equal jet Reynolds numbers. The swirl tubes with two kinds of fixed tube length of 12D and 20D are compared, where there are sequentially arranged three tangential jet inlets over the leading tube length of 12D. The numerical results show that the swirl tubes with the tube length of 12D has a much better heat transfer performance. Under equal passage Reynolds numbers, the elliptical swirl tubes with the tube length of 12D show appreciably higher Nusselt numbers by up to 22.8% and lower pressure loss coefficients by up to 69.0% than the circular tube. Under equal jet Reynolds numbers, the elliptical tubes can reduce the global heat transfer performance modestly by up to 25.6%, but reduce the pressure loss much significantly by up to 70.6%. Mostly due to much less pressure loss, the elliptical tubes have remarkably higher thermal performance in terms of the obtained heat transfer coefficient per unit pumping power for both L1 = 12D and L2 = 20D. The numerical simulations indicate that the suppression of elliptical tubes on the swirling flow development reduces the heat transfer on the wall between the jet inlets, and decreases the wall shear force and the pressure loss in the tube.
Transient Thermal Performance of Phase-Change Material Infused in Cellular Materials Based on Different Unit Cell Topologies
Authors: Nithyanandam Karthik , Singh Prashant
Published: September 2023

Phase change material (PCM) employment in thermal management and energy storage applications is limited due to their inherently low thermal conductivity. Significant enhancement in the thermal performance of PCMs can be obtained when infused in porous media with high porosity and high solid-phase thermal conductivity. Earlier studies typically employ high porosity aluminum foams obtained via a conventional manufacturing process, commonly known as foaming. A typical representative unit cell of metal foams obtained via foaming process can be of tetrakaidecahedron shape. The conventional manufacturing process of high porosity metal foams offers limited flexibility over unit cell shape, porosity, and pore density. Metal additive manufacturing advancements have the potential to address this manufacturing limitation and provides freedom in the above design domain. To this end, we have explored four different unit cell topologies, viz., octet, tetrakaidecahedron, face-diagonal cube, and cube, for their role in enhancing the transient thermal performance when infused with PCMs. An enthalpy-porosity method has been employed to model the phase-change process for wide range of variables. It has been found that the presence of solid media results in significant enhancement in PCM's thermal performance, and the Octet-shaped unit cell outperformed the other unit cell topologies explored in this study.
Experimental Investigation of a Multi Tube Burner for Premixed Hydrogen and Natural Gas Low Emission Combustion
Authors: Jaeschke Alexander , Ćosić Bernhard , Wassmer Dominik , Paschereit Christian Oliver
Published: September 2023

Hydrogen as an essential part of future decarbonization of the energy industry makes it a crucial necessity to replace conventional, natural gas based concepts in gas turbine combustion. This paper presents an experimental study of a multi-tube jet flame burner. The study is carried out with natural gas and pure hydrogen fuel at gas turbine relevant conditions at atmospheric pressure. To identify key differences between hydrogen-air and natural gas–air flames on the overall robustness and flame flashback behavior, air bulk velocity (80–120 m/s), adiabatic flame temperature (1235–2089 K) and air inlet temperature (623–673 K) are varied over a wide range, covering a range of Reynolds numbers of 10,000–20,000. Depending on flame temperature, two different flame shapes are observed for natural gas–air flames. The shape of the hydrogen-air flame changes less over the range of flame temperatures tested, but is generally more compact. The process of fuel-air mixing is further investigated by concentration distribution measurements in a water tunnel setup. Therefore, planar laser-induced fluorescence is utilized for visualization. The measured concentration distributions confirm the overall good mixing quality but also give an explanation on the observed flashback behavior of the different burner designs at reacting tests. The findings of the study are composed in a flashback correlation combining the observed flashback drivers for the burner configurations investigated.
Acoustic and Optical Investigations of the Flame Dynamics of Rich and Lean Kerosene Flames in the Primary Zone of an Air-Staged Combustion Test-Rig
Authors: March Martin , Renner Julian , Sattelmayer Thomas
Published: September 2023

In this study, the thermoacoustic behavior of nonpremixed kerosene flames from rich to lean combustion conditions is investigated. Flame-transfer-functions (FTF) measured purely acoustically are compared with results based on flame chemiluminescence. OH*, CH*, C2*, and CO2* were selected as potential measures for representing steady and fluctuating heat release when burning nonpremixed kerosene. In addition, their ability for the quantification of equivalence ratio fluctuations will be highlighted. The measurements were performed in the primary zone of an atmospheric rich-quench-lean (RQL) combustion test-rig. The new experimental approach allows a characterization of the primary zone independent of the secondary zone. Rich and lean operating points were analyzed by fueling an aero-engine prototype injector with and without acoustic excitation. To improve the quality of the acoustic wavefield reconstruction a thermocouple correction method was implemented. The flame dynamics determined with the multimicrophone method (MMM) exhibit a frequency and equivalence ratio depending effect of rich combustion conditions. The results for the steady behavior of the chosen radicals by altering equivalence ratio and thermal power indicate proportionality of the chemiluminescence to thermal power. Furthermore, the CH*/C2* ratio is found to be a promising indicator for the global equivalence ratio in the combustion chamber. The flame-transfer-functions based on chemiluminescence show a good qualitative agreement with the multimicrophone method. Based on the experimental findings a calibration curve for the different radicals to obtain quantitatively correct flame-transfer-functions from chemiluminescence is presented.
Synergies and Trade-Offs in Hybrid Propulsion Systems Through Physics-Based Electrical Component Modeling
Authors: Bermperis Dimitrios , Ntouvelos Elissaios , Kavvalos Mavroudis D. , Vouros Stavros , Kyprianidis Konstantinos G. , Kalfas Anestis I.
Published: September 2023

Hybrid-electric propulsion is recognized as an enabling technology for reducing aviation's environmental impact. In this work, a serial/parallel hybrid configuration of a 19-passenger commuter aircraft is investigated. Two underwing-mounted turboprop engines are connected to electrical branches via generators. One rear fuselage-mounted electrically driven ducted fan is coupled with an electric motor and respective electrical branch. A battery system completes the selected architecture. Consistency in modeling accuracy of propulsion systems is aimed for by development of an integrated framework. A multipoint synthesis scheme for the gas turbine and electric fan is combined with physics-based analytical modeling for electrical components. Influence of turbomachinery and electrical power system design points on the integrated power system is examined. An opposing trend between electrical and conventional powertrain mass is driven by electric fan design power. Power system efficiency improvements in the order of 2% favor high-power electric fan designs. A trade-off in electrical power system mass and performance arises from oversizing of electrical components for load manipulation. Branch efficiency improvements of up to 3% imply potential to achieve battery mass reduction due to fewer transmission losses. A threshold system voltage of 1 kV, yielding 32% mass reduction of electrical branches and performance improvements of 1–2%, is identified. This work sets the foundation for interpreting mission-level electrification outcomes that are driven by interactions on the integrated power system. Areas of conflicting interests and synergistic opportunities are highlighted for optimal conceptual design of hybrid powertrains.
The Impact of Thermal Load and Turbulent Flow on Minimum Film Thickness of a Large Tilting-Pad Journal Bearing
Authors: Vetter Daniel , Hagemann Thomas , Schwarze Hubert
Published: September 2023

Thermal loads induced by internal fluid friction significantly influence the operating behavior of high-speed journal bearings. These loads increase on average if critical Reynolds numbers are exceeded. This paper presents a detailed thermo-elasto-hydrodynamic (TEHD) analysis of a large five-pad tilting-pad journal bearing operating up to surface speeds of 94 m/s. The structure mechanical analysis is conducted by a FE-Code that is implemented as a submodule of the bearing code to improve computational efficiency. The nonlinear structure model includes the pads, their aligning ring, and the housing while the journal's thermal expansion is approximated analytically. The contact of pads and ring is modeled with a contact algorithm. Validation with test data from literature indicates the relevance of structure model's complexity. Besides the pad deflection, in particular, the consideration of the ring and housing thermal expansion is decisive in predicting the effective clearance properly. Furthermore, comparisons between measurement and simulation show that the experimentally identified nonlinear speed-dependent characteristic of minimum film thickness that features an increase due to turbulent flow is well predicted by the theoretical model. Generally, results provide an insight on the impact of the different effects dominating the behavior of the bearing in the respective speed ranges, and therefore, improve the understanding of complex bearing systems. Finally, the quality of results of approximation formulas that are easier to implement and more time efficient than the complex FE-code is investigated.
Zinc sulfide chemical vapor deposition optical ceramic analyzed by XPS
Authors: Butkus Brian , Kostogiannes Alexandros , Howe Andrew , Kang Myungkoo , Gaume Romain , Richardson Kathleen A. , Banerjee Parag
Published: September 2023

Commercially available zinc sulfide (ZnS) ceramics, synthesized using chemical vapor deposition and subsequently hot isostatically pressed, are optically transparent as compared to other zinc sulfide chemical vapor deposited films and ceramics. The unique optical transparency along with the hardness and chemical resistance of ZnS makes it an important material for infrared transmission applications. X-ray photoelectron spectroscopy and x-ray induced Auger electron spectroscopy were performed on an optically transparent ZnS ceramic. This report includes charge corrected scans for the survey along with S 2s, S 2p, S LMM, Zn 2p, Zn 2s, Zn 3d, Zn 3p, Zn 3s, Zn LMM, O 1s, and C 1s surface photoelectron signals. The scans provide photoelectron spectroscopy investigation data to help with the identification of metal sulfide compounds.
Self-assembled monolayer–based blue perovskite LEDs
Authors: Wang Ya-Kun , Jia Fengyan , Li Xiaoyue , Teale Sam , Xia Pan , Liu Yuan , Chan Phoebe Tsz-shan , Wan Haoyue , Hassan Yasser , Imran Muhammad , Chen Hao , Grater Luke , Sun Ling-Dong , Walker Gilbert C. , Hoogland Sjoerd , Lu Zheng-Hong , Yan Chun-Hua , Liao Liang-Sheng , Sargent Edward H.
Published: September 2023

Blue perovskite light-emitting diodes (LEDs) have shown external quantum efficiencies (EQEs) of more than 10%; however, devices that emit in the true blue—those that accord with the emission wavelength required for Rec. 2100 primary blue

—have so far been limited to EQEs of ~6%. We focused here on true blue emitting CsPbBr
3
colloidal nanocrystals (c-NCs), finding in early studies that they suffer from a high charge injection barrier, a problem exacerbated in films containing multiple layers of nanocrystals. We introduce a self-assembled monolayer (SAM) active layer that improves charge injection. We identified a bifunctional capping ligand that simultaneously enables the self-assembly of CsPbBr
3
c-NCs while passivating surface traps. We report, as a result, SAM-based LEDs exhibit a champion EQE of ~12% [CIE of (0.132, 0.069) at 4.0 V with a luminance of 11 cd/m
2
], and 10-fold–enhanced operating stability relative to the best previously reported Rec. 2100-blue perovskite LEDs.
Developmental emergence of sleep rhythms enables long-term memory in
Drosophila
Authors: Poe Amy R. , Zhu Lucy , Szuperak Milan , McClanahan Patrick D. , Anafi Ron C. , Scholl Benjamin , Thum Andreas S. , Cavanaugh Daniel J. , Kayser Matthew S.
Published: September 2023

In adulthood, sleep-wake rhythms are one of the most prominent behaviors under circadian control. However, during early life, sleep is spread across the 24-hour day. The mechanism through which sleep rhythms emerge, and consequent advantage conferred to a juvenile animal, is unknown. In the second-instar
Drosophila
larvae (L2), like in human infants, sleep is not under circadian control. We identify the precise developmental time point when the clock begins to regulate sleep in
Drosophila
, leading to emergence of sleep rhythms in early third-instars (L3). At this stage, a cellular connection forms between DN1a clock neurons and arousal-promoting Dh44 neurons, bringing arousal under clock control to drive emergence of circadian sleep. Last, we demonstrate that L3 but not L2 larvae exhibit long-term memory (LTM) of aversive cues and that this LTM depends upon deep sleep generated once sleep rhythms begin. We propose that the developmental emergence of circadian sleep enables more complex cognitive processes, including the onset of enduring memories.
Epigenetic variations are more substantial than genetic variations in rapid adaptation of oyster to Pacific oyster mortality syndrome
Authors: Gawra Janan , Valdivieso Alejandro , Roux Fabrice , Laporte Martin , de Lorgeril Julien , Gueguen Yannick , Saccas Mathilde , Escoubas Jean-Michel , Montagnani Caroline , Destoumieux-Garzόn Delphine , Lagarde Franck , Leroy Marc A. , Haffner Philippe , Petton Bruno , Cosseau Céline , Morga Benjamin , Dégremont Lionel , Mitta Guillaume , Grunau Christoph , Vidal-Dupiol Jeremie
Published: September 2023

Disease emergence is accelerating with global changes. Understanding by which mechanisms host populations can rapidly adapt will be crucial for management practices. Pacific oyster mortality syndrome (POMS) imposes a substantial and recurrent selective pressure on oyster populations, and rapid adaptation may arise through genetics and epigenetics. In this study, we used (epi)genome-wide association mapping to show that oysters differentially exposed to POMS displayed genetic and epigenetic signatures of selection. Consistent with higher resistance to POMS, the genes targeted included many genes in several pathways related to immunity. By combining correlation, DNA methylation quantitative trait loci, and variance partitioning, we revealed that a third of phenotypic variation was explained by interactions between the genetic and epigenetic information, ~14% by the genome, and up to 25% by the epigenome alone. Similar to genetically based adaptation, epigenetic mechanisms notably governing immune responses can contribute substantially to the rapid adaptation of hosts to emerging infectious diseases.
Gas-phase formation of the resonantly stabilized 1-indenyl (C
9
H
7
•
) radical in the interstellar medium
Authors: Yang Zhenghai , Galimova Galiya R. , He Chao , Goettl Shane J. , Paul Dababrata , Lu Wenchao , Ahmed Musahid , Mebel Alexander M. , Li Xiaohu , Kaiser Ralf I.
Published: September 2023

The 1-indenyl (C
9
H
7
•
) radical, a prototype aromatic and resonantly stabilized free radical carrying a six- and a five-membered ring, has emerged as a fundamental molecular building block of nonplanar polycyclic aromatic hydrocarbons (PAHs) and carbonaceous nanostructures in deep space and combustion systems. However, the underlying formation mechanisms have remained elusive. Here, we reveal an unconventional low-temperature gas-phase formation of 1-indenyl via barrierless ring annulation involving reactions of atomic carbon [C(
3
P)] with styrene (C
6
H
5
C
2
H
3
) and propargyl (C
3
H
3
•
) with phenyl (C
6
H
5
•
). Macroscopic environments like molecular clouds act as natural low-temperature laboratories, where rapid molecular mass growth to 1-indenyl and subsequently complex PAHs involving vinyl side-chained aromatics and aryl radicals can occur. These reactions may account for the formation of PAHs and their derivatives in the interstellar medium and carbonaceous chondrites and could close the gap of timescales of their production and destruction in our carbonaceous universe.
Viscous-capillary entrainment on bioinspired millimetric structure for sustained liquid transfer
Authors: Cheng Ziyang , Li Chuxin , Gao Can , Zhang Chengqi , Jiang Lei , Dong Zhichao
Published: September 2023

Liquid entrainment with a solid architecture passing through the fluid-fluid interface is ubiquitous and widely used in industrial processes as a liquid transfer method. Besides liquid properties, solid structures play a core role in entrainment. Although the influence of its macroscopic curvatures and microscale roughness has attracted years of research, the effect and potential of the commonly seen millimetric structures have not been sufficiently explored and exploited. Here, we demonstrate enhanced liquid entrainment on the millimetric structured surface by the co-effect of viscosity and capillarity for sustained liquid transfer of small deviation, including high-quantity uptake and practically operational drainage with small and relatively uniform droplet dripping time of varied liquid viscosities. With the overall process of viscous-capillary entrainment, we achieve stable cyclical arrayed liquid transport, showing its potential for sustained liquid transfer in intractable situations in laboratory, industry, and even daily life.
Sagnac interferometry for high-sensitivity optical measurements of spin-orbit torque
Authors: Karimeddiny Saba , Cham Thow Min Jerald , Smedley Orion , Ralph Daniel C. , Luo Yunqiu Kelly
Published: September 2023

Sagnac interferometry can provide a substantial improvement in signal-to-noise ratio compared to conventional magnetic imaging based on the magneto-optical Kerr effect. We show that this improvement is sufficient to allow quantitative measurements of current-induced magnetic deflections due to spin-orbit torque even in thin-film magnetic samples with perpendicular magnetic anisotropy, for which the Kerr rotation is second order in the magnetic deflection. Sagnac interferometry can also be applied beneficially for samples with in-plane anisotropy, for which the Kerr rotation is first order in the deflection angle. Optical measurements based on Sagnac interferometry can therefore provide a cross-check on electrical techniques for measuring spin-orbit torque. Different electrical techniques commonly give quantitatively inconsistent results so that Sagnac interferometry can help to identify which techniques are affected by unidentified artifacts.
In vitro
activity of sanitizers against mono- and polymicrobial biofilms of
C. parapsilosis
and
S. aureus
Authors: Castro Vitor de Paula , Thomaz Danilo Yamamoto , Vieira Kayro de Lima , Lopes Leonardo Guedes , Rossi Flavia , Del Negro Gilda M. B. , Benard Gil , Pires Regina Helena
Published: September 2023

The emergence of disinfectant-resistant microorganisms poses a significant threat to public health. These resilient pathogens can survive and thrive in hospital settings despite routine disinfection practices, leading to persistent infections and the potential for outbreaks. In this study, we investigated the impact of 11 different commercial sanitizers at various concentrations and exposure times on biofilms consisting of clinical and nosocomial environmental isolates of
Candida parapsilosis
and
Staphylococcus aureus
. Among the sanitizers tested, 0.5% and 2.0% chlorhexidine (CLX), 10% polyvinyl pyrrolidone (PVP-I), a disinfectant based on quaternary ammonium compound (QAC), 2% glutaraldehyde, and 0.55% orthophthalaldehyde (OPA) demonstrated efficacy against both
C. parapsilosis
and
S. aureus
in monospecies and mixed biofilms. Analysis showed that 0.5% CLX and 10% PVP-I had fungicidal and bactericidal activity against all biofilms. However, the sanitizer based on QAC and 0.55% OPA proved to be bacteriostatic and fungicidal against both monospecies and mixed biofilms. In mixed biofilms, despite the last four sanitizers exerting fungicidal action, the reduction of fungal cells was approximately 4 log
10
CFU/mL compared to monospecies biofilms, showing that the interaction provided more resistance of the yeast to the sanitizer. Formation of mixed biofilms in hospital settings can create an ecological niche that enhances the survival of pathogens against routine sanitization procedures. Therefore, effective sanitization practices, including regular cleaning with effective sanitizers, should be implemented to prevent
C. parapsilosis/S. aureus
biofilm formation in healthcare settings.