bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurements of Recirculation during Neonatal Veno-Venous Extracorporeal Membrane Oxygenation: Clinical Application of the Ultrasound Dilution Technique
Authors: Clements David , Primmer Johanna , Ryman Pamela , Marr Bonnie , Searles Bruce , Darling Edward
Published: July 2023

Recirculation during dual lumen veno-venous (DLVV) extracorporeal membrane oxygenation (ECMO) is a dynamic event that results in a fraction of the oxygenated blood exiting the arterial lumen and immediately shunting back into the venous lumen. Excessive recirculation will result in suboptimal oxygen delivery to the patient. Ultrasound dilution is a technology that has been shown to rapidly quantify recirculation in veno-venous (VV) ECMO animal models. This manuscript reports the first clinical application of ultrasound dilution in quantifying recirculation during neonatal VV ECMO. A 2.8-kg neonate with congenital diaphragmatic hernia was placed on VV ECMO using a single DLVV cannula inserted into the right atrium through the internal jugular vein. Ultrasound sensors were clamped to the arterial and venous lines near the dual lumen cannula and 3- to 5-mL bolus injections of isotonic saline were used proximal to the circuit heat exchanger to make the recirculation measurements. Recirculation measurements were made after initiation and periodically thereafter. During the 12-day ECMO period, 86 recirculation measurements were performed. The average recirculation was 34.3% (range, 15–57%). Reproducibility of paired measurements was 5.6%. Changes in patient positioning resulted in significant changes in recirculation. Measurements using platelet injections were compared with those made with saline. The two were found to closely correlate (mean difference, .25% ± 2.8%). Ultrasound dilution measurements of recirculation provided rapid monitoring data during a clinical VV ECMO procedure. Application of this technique could provide early data that will assist the clinician in guiding interventions to minimize recirculation.
Hypertonic Cardiopulmonary Bypass Primes and Endothelial Damage
Authors: Poullis Michael , Warwick Richard , Sastry Priya , Fontaine Eustace
Published: July 2023

The objective of this study was to investigate whether hypertonic hyperosmolar primes solution (HHPS), with an osmolarity of 2300 mOsmol/L, causes endothelial damage/loss. The bodies’ normal osmolarity is ˜280 mOsmol/L. Aortic endothelial cells were cultured and plated to confluence, confirmed by light microscopy, on a 96-well plate. Serial dilutions of HHPS (n = 10) were incubated with the cells (n = 160) for 1 hour. The plates were agitated to simulate flow that occurs during cardiopulmonary bypass (CPB). One half the cells (n = 80) were stained with crystal violet to provide a visual analogue of cell survival. The second half of the cells had the HHPS removed and replaced with culture medium and were incubated overnight before being stained with crystal violet. Optical densities were measured using an optical plate reader set at 470 nm. Analysis of the endothelium after 1 hour showed that HHPS (2300 mOsmol/L) and water (positive control for 100% cell death) resulted in equal cell death, which was significantly higher (p < .05) than any of the other osmolarities tested for. There was no significant difference in the endothelial death rates for osmolarities between 260 and 400 mOsmol/L. Results of overnight incubation showed that cells in contact with a solution of osmolarity >320 mOsmol/L resulted in a significantly greater endothelial cell death rate (p < .05). Our results indicate that the endothelium can be irreversibly damaged by HHPS with osmolarities >320 mOsmol/L. The experimental protocol showed that this endothelial damage, which obviously occurs at the time of contact with the HHPS, may only become manifest 24 hours later.
Hemolysis in Cardiac Surgery Patients Undergoing Cardiopulmonary Bypass: A Review in Search of a Treatment Algorithm
Authors: Vercaemst Leen
Published: July 2023

Hemolysis is a fact in all extracorporeal circuits, as shown in various studies by the increasing levels of plasma-free hemoglobin (PfHb) and decreasing levels of haptoglobin during and after cardiopulmonary bypass (CPB). Beside complete red blood cell (RBC) destruction or hemolysis, RBCs can also be damaged on a sublethal level, resulting in altered rheological properties. Increased levels of free RBC constituents together with an exhaust of their scavengers result in a variety of serious clinical sequela, such as increased systemic and pulmonary vascular resistance, altered coagulation profile, platelet dysfunction, renal tubular damage, and increased mortality. Sublethal RBC damage is characterized by decreased microperfusion and hypoxic RBCs, leading to end organ dysfunction caused by cellular ischemia. Isolated extracorporeal circuit components can be considered non-hemolytic if used according to recommendations, but extracorporeal circuit composition and management during CPB can still be optimized, avoiding cell damaging mechanical forces. Although most RBC destruction in standard CPB remains within the capacity of the endogenous clearing mechanisms, in some cases, levels of PfHb do substantially rise, and precautionary measures need to be taken. Higher degree of hemolysis can be expected in young children, after extensive surgery, and in prolonged support as in patients supported by ventricular assist devices (VADs) or extracorporeal membrane oxygenation (ECMO). These patients are especially susceptible to the toxic influences of unscavenged RBC constituents and the loss of rheologic properties of the RBCs. Considering the high percentage of neurologic and renal sequela in post-cardiotomy patients, all imbalances possibly contributing to these morbidities should be focused on and prevented, if not treated. Considering the severity of the consequences of RBC damage, the high incidence of this complication, and especially the lack of interventional strategies in cases of suspected or confirmed RBC damage, there may be a need for a treatment algorithm for this phenomenon.
A Human Factors Analysis of Cardiopulmonary Bypass Machines
Authors: Wiegmann Douglas , Suther Thomas , Neal James , Parker Sarah Henrickson , Sundt Thoralf M.
Published: July 2023

The practice of cardiovascular surgery demands daily interface with sophisticated technologies including most commonly the cardiopulmonary bypass (CPB) machine. Although other industries have recognized the importance of considering human factors in the design of machines to reduce operator error, the evolution of the CPB machine over the past half-century has been characterized by incremental modifications of component parts with attention principally to mechanical efficiency and biocompatibility, but with little awareness of the impact of design changes on the human user. As a first step in the redesign of a safer pump, systematic observations of perfusionists during 10 adult and pediatric cases were conducted by staff cardiac surgeons and by human factors experts. Observations were classified according to accepted ergonomics principles. Perfusionists also performed usability evaluations and provided feedback concerning the design and functionality of bypass machines. Problems identified clustered around several usability themes. Issues with displays (8% of total comments) included location, legibility, format, and integration. Multiple problems with controls (11% of total comments) including location, sensitivity, and shape were identified, as were issues with audible alarms (6% of total comments). Component integration (14% of comments) and workspace design (21% of comments) were suboptimal as well. Procedural and communication issues (21% of comments) related to pump utilization, rather than pump design, were also identified, which stemmed from a lack of standardized operating room practices. Clinical issues (14% of comments) surrounding care of the patient were also identified but were not further analyzed, because these comments did not pertain to the design of the perfusion pump. Our observations confirmed the hypothesis that opportunities exist to incorporate usability and ergonomics insights into CPB machine design to optimize the human/technology interface. Such fundamental design considerations may improve the safety of the conduct of CPB and, consequently, outcomes after cardiovascular surgery.
Gravity Separation of Pericardial Fat in Cardiotomy Suction Blood: An In Vitro Model
Authors: Kinard M. Rhett , Shackelford Anthony G. , Sistino Joseph J.
Published: July 2023

Fat emboli generated during cardiac surgery have been shown to cause neurologic complications in patients postoperatively. Cardiotomy suction has been known to be a large generator of emboli. This study will examine the efficacy of a separation technique in which the cardiotomy suction blood is stored in a cardiotomy reservoir for various time intervals to allow spontaneous separation of fat from blood by density. Soybean oil was added to heparinized porcine blood to simulate the blood of a patient with hypertriglyceridemia (>150 mg/dL). Roller pump suction was used to transfer the room temperature blood into the cardiotomy reservoir. Blood was removed from the reservoir in 200-mL aliquots at 0, 15, 30 45, and 60 minutes. Samples were taken at each interval and centrifuged to facilitate further separation of liquid fat. Fat content in each sample was determined by a point-of-care triglyceride analyzer. Three trials were conducted for a total of 30 samples. The 0-minute group was considered a baseline and was compared to the other four times. Fat concentration was reduced significantly in the 45- and 60-minute groups compared to the 0-, 15-, and 30-minute groups (p < .05). Gravity separation of cardiotomy suction blood is effective; however, it may require retention of blood for more time than is clinically acceptable during a routing coronary artery bypass graft surgery.
An In Vitro Study of the Effectiveness of Carbon Dioxide Flushing of Arterial Line Filters
Authors: Beckman Roland Ryan , Gisner Carl , Evans Ed
Published: July 2023

Gaseous microemboli (GMEs) have been connected to neurologic impairment and other ischemic complications after surgery. The components of the extracorporeal circuit (ECC) have a large influence on GME production. This in vitro study investigates the use of carbon dioxide flushing of the 38-μm Medtronic Affinity CB351 and 38-μm Medtronic Affinity 351 arterial line filters (ALFs) to decrease GMEs and time for air to clear the ALF. An adult circuit was implemented with a silicone oxygenator for vacuum-assisted gas removal and to reduce air before ALF. The 48 filters were separated into four equal groups: flushed coated and non-coated and non-flushed coated and non-coated. Carbon dioxide flushing was performed at 6 L/min for 3 minutes. ALFs were retrograde primed at 200 mL/min. An Emboli Detection and Classification Quantifier (EDAC) was used to gather data. The average total emboli and time to clear (seconds) for flush coated were 20.25 ± 16.78 and 142.17 ± 174.80 seconds, respectively, flushed non-coated were 30.5 ± 34.65 and 124.17 ± 131.40 seconds, non-flushed coated were 162.08 ± 79.90 and 390.42 ± 84.36 seconds, and non-flushed non-coated were 163.67 ± 212.67 and 305.92 ± 179.36 seconds. Flushed filters had an average total emboli count of 25.375 ± 27.14 and an average time to clear of 133.167 ± 151.51 seconds. Non-flushed filters had an average total emboli count of 162.875 ± 157.11 and an average time to clear of 348.167 ± 143.70 seconds. Coated and non-coated filters for total emboli and time to clear hadpvalues of .86 and .24, respectively. Flushed and non-flushed filters had total emboli and time to clearpvalues of <.001 and <.001, respectively. No significant difference was found between coated and non-coated filters involving total embolic count and time to clear. A significant difference was found in total embolic count and time to clear between flushed and non-flushed filters. This study shows that fewer emboli and faster embolic clearance time correlate with carbon dioxide flushing of the ALF.
Identifying Neonatal and Pediatric Cardiac and Congenital Diaphragmatic Hernia Extracorporeal Membrane Oxygenation Patients at Increased Mortality Risk
Authors: Grist Gary , Whittaker Carrie , Merrigan Kellie , Fenton Jason , Pallotto Eugenia , Molitor-Kirsch Erica , Ostlie Daniel , O’Brien James , Lofland Gary
Published: July 2023

A previous review from our institution established clinically measured cut-points that defined the late implementation of extracorporeal membrane oxygenation (ECMO) correlating to increased mortality in neonatal and pediatric respiratory patients. Using the same methods, this review evaluates pediatric and neonatal cardiac and congenital diaphragmatic hernia (CDH) patients to determine if the same cut-points exist in this higher risk patient population. Neonatal and pediatric cardiac and CDH patients placed on ECMO between November 1989 and December 2008 were retrospectively reviewed to determine the first adjusted anion gap (AGc), the first venoarterial carbon dioxide (CO2) gradient (p[v-a]CO2), and the first Viability Index (AGc + p[v-a]CO2= INDEX) on ECMO. These markers were then analyzed to identify the presence of specific cut-points that marked an increased risk of mortality. The timing of surgery was also reviewed to assess the surgical morbidity on survival. The review of neonatal and pediatric cardiac and CDH patients (n= 205) with an overall survival of 46% showed that all three markers were elevated to varying degrees in the expired patients (n= 110). Histograms identified the following specific cut-points for increased mortality: the AGc ≥ 23 mEq/L, the p[v-a]CO2≥ 16 mmHg, and the INDEX ≥ 28. An elevated AGc and INDEX correlated with a significantly higher risk for mortality (p< .05), survival to discharge being 20% or less. Patients under the cut-points had survival rates of 51% or higher. The timing of surgery (before or after ECMO initiation) did not significantly impact survival in the combined cardiac and CDH group. An INDEX ≥ 28 correlates with non-survival. We speculate that the late implementation of ECMO may lead to reperfusion injury, which causes reduced survival, and that ECMO intervention prior to reaching the cut-points may improve survival in neonatal and pediatric cardiac and CDH patients.
Modified Surface Coatings and their Effect on Drug Adsorption within the Extracorporeal Life Support Circuit
Authors: Preston Thomas J. , Ratliff Todd M. , Gomez Daniel , Olshove Vincent F. , Nicol Kathleen K. , Sargel Cheryl L. , Chicoine Louis G.
Published: July 2023

A recently completed study quantified the percent of fentanyl or morphine sulfate lost to uncoated polyvinylchloride (PVC) tubing or to one of two hollow fiber oxygenators within the extracorporeal life support (ECLS) circuit. The results demonstrated the majority of drug loss was due to adsorption by the PVC tubing. The purpose of this study was to determine if a tubing coating process affects fentanyl or morphine Sulfate adsorption. The goal was to quantify fentanyl or morphine sulfate lost due to adhesion within surface modified tubing. The following surface modifications were studied: 1) Maquet Safeline® (synthetic immobilized albumin); 2) Maquet Softline® (a heparin free biopassive polymer); 3) Maquet Bioline® (recombinant human albumin + heparin) (Maquet Cardiopulmonary AG, Hirrlingen, Germany); 4) Terumo X Coating™ (poly2methoxylacrylate)) (Terumo Cardiovascular Systems Corporation, Ann Arbor, MI); 5) Medtronic Carmeda® (covalently bonded heparin); and 6) Medtronic Trillium® (covalently bonded heparin) (Medtronic, Minneapolis, MN). A total of 36 individual circuits were built from the above six available modified surface coatings, for a total of six individual circuits of each coating type. Blood samples were drawn at 5 minutes, 120 minutes, and 360 minutes followed by High-Performance Liquid Chromatography to determine available circulating levels of either fentanyl or morphine sulfate. Fentanyl concentrations decreased to an average final available concentration of 35% (±5%) within the 18 circuits. Morphine sulfate however, decreased to a final available concentration of 57% (±1%) in all Maquet tubing and the Medtronic Trillium tubing, while it decreased to a final concentration of 35% (±1%) in the Medtronic Carmeda coated tubing and in the Terumo X Coating tubing. Biocompatible ECLS circuit surface coatings affected drug-adsorption and availability. Further evaluation is necessary to understand the adsorptive loss of other drugs administered to our patients while on modified surface coated ECLS circuits.
Monitoring Microemboli During Cardiopulmonary Bypass with the EDAC® Quantifier
Authors: Lynch John E. , Wells Christopher , Akers Tom , Frantz Paul , Garrett Donna , Scott M. Lance , Williamson Lisa , Agnew Barbara , Lynch John K.
Published: July 2023

Gaseous emboli may be introduced into the bypass circuit both from the surgical field and during perfusionist interventions. While circuits provide good protection against massive air embolism, they do not remove gaseous microemboli (GME) from the bypass circuit. The purpose of this preliminary study is to assess the incidence of GME during bypass surgery and determine if increased GME counts were associated with specific events during bypass surgery. In 30 cases divided between 15 coronary artery bypass grafts and 15 valve repairs, GME were counted and sized at the three locations on the bypass circuit using the EDAC® Quantifier (Luna Innovations, Roanoke, VA). A mean of 45,276 GME were detected after the arterial line filter during these 30 cases, with significantly more detected (p= .04) post filter during valve cases (mean = 72,137 ± 22,113) than coronary artery bypass graft cases (mean = 18,416 ± 7831). GME detected post filter were significantly correlated in time with counts detected in the venous line (p< .001). Specific events associated with high counts included the initiation of cardiopulmonary bypass, heart manipulations, insertion and removal of clamps, and the administration of drugs. Global factors associated with increased counts post filter included higher venous line counts and higher post reservoir/bubble trap counts. The mean number of microemboli detected during bypass surgery was much higher than reported in other studies of emboli incidence, most likely due to the increased sensitivity of the EDAC® Quantifier compared to other detection modalities. The results furthermore suggest the need for further study of the clinical significance of these microemboli and what practices may be used to reduce GME incidence. Increased in vitro testing of the air handling capability of different circuit designs, along with more clinical studies assessing best clinical practices for reducing GME activity, is recommended.
Impact of investment in quality language education on green economic growth: case study of 23 Chinese provinces
Authors: Zhang Ming , Wei XueJiao , Xu Aidi
Published: July 2023

The spread of the threat of climate change has forced countries to try to implement the drivers of green economic growth. In this paper, we seek to explore how green growth is affected by quality language education in 23 Chinese provinces from 2010 to 2021. Employing the ARDL (Autoregressive Distributed Lag) approach and Pooled Mean Group (PMG) estimator, the findings confirmed that a 1% increase in the quality of language education improves sustainable economic growth in Chinese provinces by 0.69% and 0.01% in the short and long term, respectively. Furthermore, the development of sustainable electricity generation is the increasing factor of green prosperity in Chinese provinces. Moreover, any increase in waste generation will harshly impact the sustainable growth of Chinese provinces by 0.57% and 0.15% in the short and long term, respectively. The volume of green investment positively correlates with sustainable growth in Chinese provinces. As the primary policy implication, it is recommended that the Chinese government expand the education for sustainable development (ESD) program, develop social literacy on participation in sustainable power generation, and improve the SMEs' education for green job creation and sustainable investment.
Between piece molds and lost wax: the casting of a diatrete ornamentation in early China rethought
Authors: Peng Peng
Published: July 2023

For a long time, research on the pre-Han (before 202 BCE) Chinese use of the lost-wax process was targeted at demonstrating that it was of no use at all. That position was severely shaken when thezun-panset of Zeng Hou Yi (“Marquis Yi of Zeng,” d. 433 BCE) was unearthed at Hubei Suizhou in 1978, along with subsequently excavated finds or rediscovered artifacts carrying similarly interpenetrating openwork. Since the early 2000s, however, there has been a persistent revival of a research orientation against the use of the lost-wax process in Bronze Age China. After surging first in Chinese academia, the new tide took some time to arrive in the West. A response to Donna Strahan’s prestigious lecture, “Debating the Use of Lost-wax Casting in Ancient China,” this article presents my thinking about lost wax versus piece molds in early Chinese casting practices. Strahan’s studied “diatrete” ornamentation in the Metropolitan Museum of Art, to me, can be securely identified as lost-wax cast thanks to some telltale traces. Through this critical investigation, I invite my fellow art historians, archaeologists, and historians of metal technology to emerge from the “doubting of lost wax” era to tackle new challenges in early Chinese archaeo-metallurgy.
Characterization of mesoscopic turbulent transport events with long-radial-range correlation in DIII-D H-mode plasmas
Authors: Hong R. , Rhodes T. L. , Ren Y. , Diamond P. H. , Jian X. , Zeng L. , Barada K. , Yan Z. , McKee G. R.
Published: July 2023

A dimensionless collisionality scan has been performed in H-mode plasmas on DIII-D tokamak, with detailed measurements of intermediate-to-high wavenumber turbulence using Doppler backscattering systems. It is found that the shorter wavelength turbulence develops into spatially asymmetric turbulent structures with a long-radial-range correlation (LRRC) in the mid-radius region of high collisionality discharges. Linear cgyro simulations indicate that the underlying turbulence is likely driven by the electron-temperature-gradient mode. The LRRC transport events are highly intermittent and show a power spectrum of Sñ(k⊥)∝k⊥−1 for density fluctuations, which is often associated with self-organized criticality. The magnitude and the radial scale of those turbulent structures increase significantly when the Er×B mean flow shearing rate decreases at higher collisionality. The enhanced LRRC transport events appear to be correlated with the degraded energy confinement time. The emergence of such LRRC transport events may serve as a candidate explanation for the degrading nature of H-mode core plasma confinement at high collisionality.
Evaluating batteries for renewable energy storage: A hybrid MCDM framework based on combined objective weights and uncertainty-preserved COPRAS
Authors: Guan Yongxin , Liu Zhongfang , Du Yunxi , Xu Di
Published: July 2023

Battery technologies offer promising solutions for renewable energy storage. However, selecting the most suitable battery requires proper investigation. This study introduces a multi-criteria decision-making framework for assessing batteries based on various criteria and uncertain data, by using a combined objective weighting method and an uncertainty-preserved complex proportional assessment (UP-COPRAS). The proposed weighting method ensures objectivity and fairness in the weighting result by integrating interval entropy and a gray relational coefficient-supported decision-making trial and evaluation laboratory to capture variation and correlation degrees among the criteria. After incorporating interval numbers with a compensatory ranking method, the UP-COPRAS prioritizes batteries in a simple yet rigorous way using uncertain evaluation data. To test the feasibility of the framework, an illustrative case was employed to assess four battery alternatives using a five-dimensional criteria system. Through results comparison, two mathematical contributions are confirmed. First, the combined objective weighting method uses the variation and correlation features of numerical data to determine criteria weights, which prevents subjective manipulation and eliminates bias in statistical analysis. Second, the UP-COPRAS preserves uncertainties throughout the evaluation, resulting in a rational decision output by eliminating interference in the original data.
Early stage damage detection of wind turbine blades based on UAV images and deep learning
Authors: Gao Ruxin , Ma Yongfei , Wang Tengfei
Published: July 2023

In response to the shortcomings of existing image detection algorithms in the early damage detection of wind turbine blades, such as insufficient applicability and unsatisfactory detection results, this paper proposes an improved DINO (DETR with improved denoizing anchor boxes for end-to-end object detection) model for wind turbine blade damage detection called WTB-DINO. The improvement strategy of the DINO model is obtained by collecting and analyzing unmanned aerial vehicle (UAV) daily inspection image data in wind farms. First, the lightweight design of DINO's feature extraction backbone is implemented to meet the requirement of fast and effective video inspection by drones. Based on this, the Focus down-sampling and enhanced channel attention mechanism are incorporated into the model to enhance the feature extraction ability of the Backbone for damaged areas according to the characteristics of wind turbine blade images. Second, a parallel encoder structure is built, and a multi-head attention mechanism is used to model the relationship between samples for each type of damage with uneven distribution in the dataset to improve the feature modeling effect of the model for less-sample damage categories. Experimental results show that the WTB-DINO model achieves a detection precision and recall rate of up to 93.2% and 93.6% for wind turbine blade damage, respectively, while maintaining a high frame rate of 27 frames per second. Therefore, the proposed WTB-DINO model can accurately and in real-time classify and locate damaged areas in wind turbine blade images obtained by UAVs.
High-speed photon correlation monitoring of amplified quantum noise by chaos using deep-learning balanced homodyne detection
Authors: Guo Yanqiang , Hu Zinan , Zhang Jianchao , Zhu Chenyu , Guo Xiaomin
Published: July 2023

Precision experimental determination of photon correlation requires massive amounts of data and extensive measurement time. We present a technique to monitor second-order photon correlation g(2)(0) of amplified quantum noise based on wideband balanced homodyne detection and deep-learning acceleration. The quantum noise is effectively amplified by an injection of weak chaotic laser, and the g(2)(0) of the amplified quantum noise is measured with a real-time sample rate of 1.4 GHz. We also exploit a photon correlation convolutional neural network accelerating correlation data using a few quadrature fluctuations to perform a parallel processing of g(2)(0) for various chaos injection intensities and effective bandwidths. The deep-learning method accelerates the g(2)(0) experimental acquisition with a high accuracy, estimating 6107 sets of photon correlation data with a mean square error of 0.002 in 22 s and achieving a three orders of magnitude acceleration in the data acquisition time. This technique contributes to a high-speed and precision coherence evaluation of entropy source in secure communication and quantum imaging.
Analysis of the wake flow behind concave curved cylinders with velocity measurements by particle image velocimetry and modal decomposition
Authors: Chiatto Matteo , Cardinale Caroline , Shang Jessica K. , Grasso Francesco
Published: July 2023

The properties of the wake flow behind concave curved cylinders have been investigated analyzing simultaneously the mean velocity profiles extracted along concentric arcs parallel to the cylinder axis and the dynamically most relevant coherent structures obtained by spectral proper orthogonal decomposition. These analyzes have allowed us to determine the position, the extension, and the evolution of the different wake regimes. The velocity measurements have been obtained through the stereo particle image velocimetry (stereo-PIV) technique. The study considers various Reynolds numbers, based on cylinder diameter (240<Re<840), and curvatures. The quarter-of-ring cylinder is first analyzed. Near the cylinder root, the flow exhibits a topology dominated by an oblique vortex shedding, contrary to what is observed in the literature for similar geometric configurations. We attribute this disagreement to differences in the treatment of the free-end conditions that play a role in triggering the shedding regime. We find that the local shedding inclination is driven by the axial velocity, whereas its extension and wavelength depend mainly on the Reynolds number. The near free-end region presents, instead, two counter-rotating standing vortices that induce a cross-wise velocity directed toward the cylinder root and a tip vortex that expands evolving downstream. As the Reynolds number increases, the wake presents irregularities and the shedding spreads becoming nearly normal to the incoming flow. At smaller curvatures, the cylinder free-end becoming more inclined with respect to the incoming flow, and the free-end effects are enhanced. The interaction with the vortex sheets of the standing vortices that develop at the leeward side weakens. As a consequence, these vortices stretch in the stream-wise direction giving rise to the trailing vortices that stem from the cylinder surface and affect the cross-wise velocity distributions.
Mid-infrared swept cavity-enhanced photoacoustic spectroscopy using a quartz tuning fork
Authors: Nie Qinxue , Wang Zhen , Borri Simone , Natale Paolo De , Ren Wei
Published: July 2023

We report the development of swept cavity-enhanced photoacoustic spectroscopy using a quartz tuning fork for ultra-sensitive and high-resolution molecular spectroscopy. By using a quantum cascade laser (QCL) as the mid-infrared light source, a dual-feedback Pound–Drever–Hall locking method is proposed to lock the QCL frequency to a continuously swept optical cavity. By placing an off-beam quartz-enhanced photoacoustic spectroscopy module in a 48-mm Fabry–Pérot cavity, we are able to achieve ultra-sensitive gas detection based on the doubly resonant photoacoustic effect. As a proof-of-concept, we use a distributed feedback QCL to exploit the CO line at 2190.02 cm−1, where the cavity-locked QCL is scanned over a spectral range of 10 GHz with a spectral resolution of ∼3 MHz. With the incident laser power of 7.3 mW, the optical cavity (finesse 1931) builds up the intracavity power beyond 3 W. Our photoacoustic spectrometer achieves the minimum detection limit of 375 part-per-trillion (ppt) at the averaging time of 150 s and the normalized noise equivalent absorption coefficient of 1.27 × 10−9 Wcm−1 Hz−1/2.
Dirac cones in bipartite square–octagon lattice: A theoretical approach
Authors: He Junwei , Liu Zhirong
Published: July 2023

Dirac cones are difficult to achieve in a square lattice with full symmetry. Here, we have theoretically investigated a bipartite tetragonal lattice composed of tetragons and octagons using both Tight-Binding (TB) model and density functional theory (DFT) calculations. The TB model predicts that the system exhibits nodal line semi-metallic properties when the on-site energies of all atoms are identical. When the on-site energies differ, the formation of an elliptical Dirac cone is predicted. Its physical properties (anisotropy, tilting, merging, and emerging) can be regulated by the hopping energies. An exact analytical formula is derived to determine the position of the Dirac point by the TB parameters, and a criterion for the existence of Dirac cones is obtained. The “divide-and-coupling” method is applied to understand the origin of the Dirac cone, which involves dividing the bands into several groups and examining the couplings among inter-groups and intra-groups. Various practical systems computed by DFT methods, e.g., t-BN, t-Si, 4,12,2-graphyne, and t-SiC, are also examined, and they all possess nodal lines or Dirac cones as predicted by the TB model. The results provide theoretical foundation for designing novel Dirac materials with tetragonal symmetry.
Demonstration of a 4.32
μ
m cutoff InAsSbBi nBn photodetector, a lattice-matched random alloy III–V solution for mid-wave infrared sensing
Authors: Webster P. T. , Logan J. V. , Helms L. , Grant P. C. , Hains C. , Carrasco R. A. , Newell A. T. , Milosavljevic M. S. , Johnson S. R. , Balakrishnan G. , Maestas D. , Morath C. P.
Published: July 2023

InAsSbBi nBn photodetectors are demonstrated that are lattice-matched to the underlying GaSb substrate with a 4.32 μm wavelength cutoff at 150 K that is 0.3 μm longer than that of lattice-matched InAsSb at this temperature reflecting a 0.5% Bi mole fraction in the InAsSbBi active region. A low growth temperature was utilized to facilitate the incorporation of Bi, resulting in a minority carrier lifetime on the order of 24 ns in the InAsSbBi active region. Nevertheless, the detectors exhibit a quantum efficiency of 17% at 3.3 μm wavelength with a dark current density of 50 μA/cm2 at 150 K and −0.4 V bias and the strong photoresponse turn-on characteristic of a random alloy at 4.32 μm wavelength and 150 K. A shot noise-equivalent irradiance analysis indicates that this detectors' dark-current-limited noise-equivalent irradiance of 1012 cm−2 s−1 is two orders of magnitude greater than the Rule 07 expectation for this cutoff, and dark-current-limited shot noise-equivalent irradiance performance transitions to photon-limited at 1.7 × 1015 photons/cm2 s.
Tunable d0 magnetism of hexagonal boron nitride introduced through an adjacent doping strategy
Authors: Wang Boyu , Ning Jing , Zhang Jincheng , Wang Dong , Zhang Chi , Hao Yue
Published: July 2023

To meet the current requirements of diluted magnetic semiconductors (DMSs) resulting from continuous advancements in spintronics, designing d0 DMSs with high stability, spin polarization, and Curie temperature is essential. Present research on introducing d0 magnetism is limited to monatomic doping, lacking regulation measures for local magnetic moments and long range magnetic coupling. Herein, an adjacent doping strategy is employed to introduce degrees of freedom for tuning the magnetic properties of d0 DMSs. It is observed that by introducing Si and O atoms as central and adjacent dopants, respectively, the intrinsically nonmagnetic hexagonal boron nitride (h-BN) exhibits significant local magnetic moments. Furthermore, it is observed that the ionization energy, total magnetic moment, magnetic coupling, and Curie temperature of the doped h-BN are susceptible to the Si–O coordination. Subsequently, a magnetic half-metal (Si–O3-doped h-BN) with high thermal stability, 100% spin polarization, long range ferromagnetic coupling, and high Curie temperature is designed through high Si–O coordination doping. This study proposes a feasible approach for introducing tunable d0 magnetism using the design of Si–O adjacent-doped h-BN as an example.
Loss of flockmates weakens winter site fidelity in golden-crowned sparrows (
Zonotrichia atricapilla
)
Authors: Madsen Anastasia E. , Lyon Bruce E. , Chaine Alexis S. , Block Theadora A. , Shizuka Daizaburo
Published: July 2023

Animal social interactions have an intrinsic spatial basis as many of these interactions occur in spatial proximity. This presents a dilemma when determining causality: Do individuals interact socially because they happen to share space, or do they share space because they are socially linked? We present a method that uses demographic turnover events as a natural experiment to investigate the links between social associations and space use in the context of interannual winter site fidelity in a migratory bird. We previously found that golden-crowned sparrows (
Zonotrichia atricapilla
) show consistent flocking relationships across years, and that familiarity between individuals influences the dynamics of social competition over resources. Using long-term data on winter social and spatial behavior across 10 y, we show that i) sparrows exhibit interannual fidelity to winter home ranges on the scale of tens of meters and ii) the precision of interannual site fidelity increases with the number of winters spent, but iii) this fidelity is weakened when sparrows lose close flockmates from the previous year. Furthermore, the effect of flockmate loss on site fidelity was higher for birds that had returned in more than 2 winters, suggesting that social fidelity may play an increasingly important role on spatial behavior across the lifetime of this migratory bird. Our study provides evidence that social relationships can influence site fidelity, and shows the potential of long-term studies for disentangling the relationship between social and spatial behavior.
Generation of a measurable magnetic field in a metal asteroid with a rubble-pile core
Authors: Zhang Zhongtian , Bercovici David
Published: July 2023

Paleomagnetic records of iron meteorites of the IVA group suggest that their parent body (an inward-solidified metal asteroid) possessed an internal magnetic field. The origin of this magnetism is enigmatic because inward solidification typically leads to light element release from the top of the liquid, which depresses convection and dynamo activity. Here, we propose a possible scenario to help resolve this paradox. The formation of a metal asteroid must involve a disruptive, mantle-stripping collision and the reaccretion of metal fragments. We hypothesize that a small portion of metal fragments may have substantially cooled before being reaccreted. These fragments could have formed a cold, rubble-pile inner core, which extracted heat from the liquid layer, leading to solidification and light element expulsion at the inner core boundary to power a dynamo. In the portions of the inward-growing crust that cooled below the remanence acquisition temperature, the magnetic field could be recorded.
Effect of water on seismic attenuation of the upper mantle: The origin of the sharp lithosphere–asthenosphere boundary
Authors: Liu Chao , Yoshino Takashi , Yamazaki Daisuke , Tsujino Noriyoshi , Gomi Hitoshi , Sakurai Moe , Zhang Youyue , Wang Ran , Guan Longli , Lau Kayan , Tange Yoshinori , Higo Yuji
Published: July 2023

Oceanic lithosphere moves over a mechanically weak layer (asthenosphere) characterized by low seismic velocity and high attenuation. Near mid-ocean ridges, partial melting can produce such conditions because of the high-temperature geotherm. However, seismic observations have also shown a large and sharp velocity reduction under oceanic plates at the lithosphere–asthenosphere boundary (LAB) far from mid-ocean ridges. Here, we report the effect of water on the seismic properties of olivine aggregates in water-undersaturated conditions at 3 GPa and 1,223 to 1,373 K via in-situ X-ray observation using cyclic loading. Our results show that water substantially enhances the energy dispersion and reduces the elastic moduli over a wide range of seismic frequencies (0.5 to 1,000 s). An attenuation peak that appears at higher frequencies (1 to 5 s) becomes more pronounced as the water content increases. If water exists only in the asthenosphere, this is consistent with the observation that the attenuation in the asthenosphere is almost constant over a wide frequency range. These sharp seismic changes at the oceanic LAB far from mid-ocean ridges could be explained by the difference in water content between the lithosphere and asthenosphere.
GABAergic miR-34a regulates Dorsal Raphè inhibitory transmission in response to aversive, but not rewarding, stimuli
Authors: Ielpo Donald , Guzzo Serafina M. , Porcheddu Giovanni F. , Viscomi Maria Teresa , Catale Clarissa , Reverte Ingrid , Cabib Simona , Cifani Carlo , Antonucci Gabriella , Ventura Rossella , Lo Iacono Luisa , Marchetti Cristina , Andolina Diego
Published: July 2023

The brain employs distinct circuitries to encode positive and negative valence stimuli, and dysfunctions of these neuronal circuits have a key role in the etiopathogenesis of many psychiatric disorders. The Dorsal Raphè Nucleus (DRN) is involved in various behaviors and drives the emotional response to rewarding and aversive experiences. Whether specific subpopulations of neurons within the DRN encode these behaviors with different valence is still unknown. Notably, microRNA expression in the mammalian brain is characterized by tissue and neuronal specificity, suggesting that it might play a role in cell and circuit functionality. However, this specificity has not been fully exploited. Here, we demonstrate that microRNA-34a (miR-34a) is selectively expressed in a subpopulation of GABAergic neurons of the ventrolateral DRN. Moreover, we report that acute exposure to both aversive (restraint stress) and rewarding (chocolate) stimuli reduces GABA release in the DRN, an effect prevented by the inactivation of DRN miR-34a or its genetic deletion in GABAergic neurons in aversive but not rewarding conditions. Finally, miR-34a inhibition selectively reduced passive coping with severe stressors. These data support a role of miR-34a in regulating GABAergic neurotransmitter activity and behavior in a context-dependent manner and suggest that microRNAs could represent a functional signature of specific neuronal subpopulations with valence-specific activity in the brain.
Giant self-driven exciton-Floquet signatures in time-resolved photoemission spectroscopy of MoS
2
from time-dependent GW approach
Authors: Chan Y.-H. , Qiu Diana Y. , da Jornada Felipe H. , Louie Steven G.
Published: July 2023

Time-resolved, angle-resolved photoemission spectroscopy (TR-ARPES) is a one-particle spectroscopic technique that can probe excitons (two-particle excitations) in momentum space. We present an ab initio, time-domain GW approach to TR-ARPES and apply it to monolayer MoS
2
. We show that photoexcited excitons may be measured and quantified as satellite bands and lead to the renormalization of the quasiparticle bands. These features are explained in terms of an exciton-Floquet phenomenon induced by an exciton time–dependent bosonic field, which are orders of magnitude stronger than those of laser field–induced Floquet bands in low-dimensional semiconductors. Our findings imply a way to engineer Floquet matter through the coherent oscillation of excitons and open the new door for mechanisms for band structure engineering.
The transformative power of transformers in protein structure prediction
Authors: Moussad Bernard , Roche Rahmatullah , Bhattacharya Debswapna
Published: July 2023

Transformer neural networks have revolutionized structural biology with the ability to predict protein structures at unprecedented high accuracy. Here, we report the predictive modeling performance of the state-of-the-art protein structure prediction methods built on transformers for 69 protein targets from the recently concluded 15th Critical Assessment of Structure Prediction (CASP15) challenge. Our study shows the power of transformers in protein structure modeling and highlights future areas of improvement.
Phase separation and ripening in a viscoelastic gel
Authors: Curk Tine , Luijten Erik
Published: July 2023

The process of phase separation in elastic solids and viscous fluids is of fundamental importance to the stability and function of soft materials. We explore the dynamics of phase separation and domain growth in a viscoelastic material such as a polymer gel. Using analytical theory and Monte Carlo simulations, we report a domain growth regime in which the domain size increases algebraically with a ripening exponentαthat depends on the viscoelastic properties of the material. For a prototypical Maxwell material, we obtainα=1, which is markedly different from the well-known Ostwald ripening process withα=1/3. We generalize our theory to systems with arbitrary power-law relaxation behavior and discuss our findings in the context of the long-term stability of materials as well as recent experimental results on phase separation in cross-linked networks and cytoskeleton.
Using single-cell RNA sequencing to generate predictive cell-type-specific split-GAL4 reagents throughout development
Authors: Chen Yu-Chieh David , Chen Yen-Chung , Rajesh Raghuvanshi , Shoji Nathalie , Jacy Maisha , Lacin Haluk , Erclik Ted , Desplan Claude
Published: July 2023

Cell-type-specific tools facilitate the identification and functional characterization of the distinct cell types that form the complexity of neuronal circuits. A large collection of existing genetic tools in
Drosophila
relies on enhancer activity to label different subsets of cells and has been extremely useful in analyzing functional circuits in adults. However, these enhancer-based GAL4 lines often do not reflect the expression of nearby gene(s) as they only represent a small portion of the full gene regulatory elements. While genetic intersectional techniques such as the split-GAL4 system further improve cell-type-specificity, it requires significant time and resources to screen through combinations of enhancer expression patterns. Here, we use existing developmental single-cell RNA sequencing (scRNAseq) datasets to select gene pairs for split-GAL4 and provide a highly efficient and predictive pipeline (scMarco) to generate cell-type-specific split-GAL4 lines at any time during development, based on the native gene regulatory elements. These gene-specific split-GAL4 lines can be generated from a large collection of coding intronic MiMIC/CRIMIC lines or by CRISPR knock-in. We use the developing
Drosophila
visual system as a model to demonstrate the high predictive power of scRNAseq-guided gene-specific split-GAL4 lines in targeting known cell types, annotating clusters in scRNAseq datasets as well as in identifying novel cell types. Lastly, the gene-specific split-GAL4 lines are broadly applicable to any other
Drosophila
tissue. Our work opens new avenues for generating cell-type-specific tools for the targeted manipulation of distinct cell types throughout development and represents a valuable resource for the
Drosophila
community.
Activin E–ACVR1C cross talk controls energy storage via suppression of adipose lipolysis in mice
Authors: Adam Rene C. , Pryce Dwaine S. , Lee Joseph S. , Zhao Yuanqi , Mintah Ivory J. , Min Soo , Halasz Gabor , Mastaitis Jason , Atwal Gurinder S. , Aykul Senem , Idone Vincent , Economides Aris N. , Lotta Luca A. , Murphy Andrew J. , Yancopoulos George D. , Sleeman Mark W. , Gusarova Viktoria
Published: July 2023

Body fat distribution is a heritable risk factor for cardiovascular and metabolic disease. In humans, rare Inhibin beta E (
INHBE
, activin E) loss-of-function variants are associated with a lower waist-to-hip ratio and protection from type 2 diabetes. Hepatic fatty acid sensing promotes
INHBE
expression during fasting and in obese individuals, yet it is unclear how the hepatokine activin E governs body shape and energy metabolism. Here, we uncover activin E as a regulator of adipose energy storage. By suppressing β-agonist-induced lipolysis, activin E promotes fat accumulation and adipocyte hypertrophy and contributes to adipose dysfunction in mice. Mechanistically, we demonstrate that activin E elicits its effect on adipose tissue through ACVR1C, activating SMAD2/3 signaling and suppressing PPARG target genes. Conversely, loss of activin E or ACVR1C in mice increases fat utilization, lowers adiposity, and drives PPARG-regulated gene signatures indicative of healthy adipose function. Our studies identify activin E–ACVR1C as a metabolic rheostat promoting liver–adipose cross talk to restrain excessive fat breakdown and preserve fat mass during prolonged fasting, a mechanism that is maladaptive in obese individuals.