bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Advances on High-Order Dipolar Annulations of Donor–Acceptor Cyclopropanes/Cyclobutanes
Authors: Peng Shiyong , Yang Liangliang , Wang Haiyang , Lang Ming
Published: August 2023

This short review summarizes the recent impressive developments on the high-order dipolar annulations (HODAs) of donor–acceptor cyclopropanes (DACs) and donor–acceptor cyclobutanes (DABs) to afford medium-sized (hetero)cycles.

1 Introduction

2 (3+m) (m > 3) Annulations of Donor–Acceptor Cyclopropanes

2.1 (3+4) Annulations

2.2 (3+5) Annulations

3 (4+m) (m > 2) Annulations of Donor–Acceptor Cyclobutanes

4 Conclusion
Photoredox-Catalyzed Radical–Radical Coupling of Potassium Trifluoroborates with Acyl Azoliums
Authors: Rourke Michael J. , McGill Matthew J. , Scheidt Karl A. , Yang Daniel , Farnam Emelia J. , Zhu Joshua L.
Published: August 2023

Potassium trifluoroborates have gained significant utility as coupling partners in organic synthesis, particularly in the Suzuki–Miyaura coupling reaction. Recently, they have also been used as radical precursors under oxidative conditions to generate carbon-centered radicals. These versatile reagents have found new applications in photoredox catalysis, including radical substitution, conjugate-addition reactions, and transition-metal dual catalysis. In addition, this photomediated redox-neutral process has enabled radical–radical coupling with persistent radicals in the absence of a metal, and this process remains to be fully explored. In this study, we report the radical–radical coupling of potassium benzylic trifluoroborate salts with isolated acyl azolium triflates, which are persistent-radical precursors. The reaction is catalyzed by an organic photocatalyst and forms isolable tertiary alcohol species. These products can be transformed into a range of substituted ketone products by simple treatment with a mild base.
The Efficacy and Safety of Topical Saline Irrigation with Tranexamic Acid on Perioperative Blood Loss in Patients Treated with Percutaneous Endoscopic Interlaminar Diskectomy: A Retrospective Study
Authors: Zhang Yu , Zhao Wenjie , Hu Man , Liu Xin , Peng Qing , Meng Bo , Yang Sheng , Feng Xinmin , Zhang Liang
Published: August 2023

Background Tranexamic acid (TXA) is safe and effective in preventing bleeding during spinal surgery. However, there is currently no relevant research on the efficacy and safety of adding TXA to the saline irrigation fluid in percutaneous endoscopic interlaminar diskectomy (PEID). This study aimed to evaluate the efficacy and safety of topical saline irrigation with TXA for PEID in the treatment of lumbar disk herniation.

Methods In this single-center, retrospective cohort study, patients who underwent PEID for L5–S1 lumbar disk herniation were included and allocated to two groups according to whether they had been administered TXA. PEID was performed with saline irrigation fluid containing 0.33 g of TXA per 1 L of saline in the TXA group (n = 38). In the control group (n = 51), the saline irrigation fluid was injected with the same volume of normal saline. All PEIDs were performed by the same spine surgery team. The hidden blood loss (HBL), intraoperative blood loss (IBL), total blood loss (TBL), amount of fluid used, operation time, visual clarity, hospital stay, blood transfusion rate, coagulation index, and complication rate were compared between the two groups.

Results The TBL, HBL, and IBL in the TXA group were significantly lower than those of the control group. The postoperative hemoglobin in the TXA group was significantly higher than that of the control group. Visual clarity was significantly better and the operation time was significantly shorter in the TXA group. However, there was no significant difference in postoperative hematocrit, blood coagulation function, amount of fluid used, blood transfusion rate, and perioperative complications between the two groups.

Conclusion In PEID, the addition of TXA to topical saline irrigating fluid can significantly reduce the HBL, IBL, and TBL. The addition of TXA to topical saline irrigating fluid can improve visual clarity in the surgery and reduce operation time, but it does not change the coagulation function or the complication rate.
A Multiyear Survey Evaluating Clinician Electronic Health Record Satisfaction
Authors: Garabedian Pamela M. , Rui Angela , Volk Lynn A. , Neville Bridget A. , Lipsitz Stuart R. , Healey Michael J. , Bates David W.
Published: August 2023

Objectives We assessed how clinician satisfaction with a vendor electronic health record (EHR) changed over time in the 4 years following the transition from a homegrown EHR system to identify areas for improvement.

Methods We conducted a multiyear survey of clinicians across a large health care system after transitioning to a vendor EHR. Eligible clinicians from the first institution to transition received a survey invitation by email in fall 2016 and then eligible clinicians systemwide received surveys in spring 2018 and spring 2019. The survey included items assessing ease/difficulty of completing tasks and items assessing perceptions of the EHR's value, usability, and impact. One item assessing overall satisfaction and one open-ended question were included. Frequencies and means were calculated, and comparison of means was performed between 2018 and 2019 on all clinicians. A multivariable generalized linear model was performed to predict the outcome of overall satisfaction.

Results Response rates for the surveys ranged from 14 to 19%. The mean response from 3 years of surveys for one institution, Brigham and Women's Hospital, increased for overall satisfaction between 2016 (2.85), 2018 (3.01), and 2019 (3.21, p < 0.001). We found no significant differences in mean response for overall satisfaction between all responders of the 2018 survey (3.14) and those of the 2019 survey (3.19). Systemwide, tasks rated the most difficult included “Monitoring patient medication adherence,” “Identifying when a referral has not been completed,” and “Making a list of patients based on clinical information (e.g., problem, medication).” Clinicians disagreed the most with “The EHR helps me focus on patient care rather than the computer” and “The EHR allows me to complete tasks efficiently.”

Conclusion Survey results indicate room for improvement in clinician satisfaction with the EHR. Usability of EHRs should continue to be an area of focus to ease clinician burden and improve clinician experience.
Safety and Efficacy of Genicular Artery Embolization for the Treatment of Knee Pain Secondary to Osteoarthritis—Initial Indian Experience
Authors: Gorsi Ujjwal , Singh Damandeep , Kang Mandeep , Kumar Vishal , Prakash Mahesh , B.C Sreedhara
Published: August 2023

Background Osteoarthritis (OA) is the commonest form of arthritis with pain and disability as hallmark symptoms. Despite various nonpharmacologic, pharmacologic, and surgical approaches, pain control may be hard to achieve. Over the last few years, few studies have been conducted on managing knee OA using novel endovascular genicular artery embolization (GAE) with varied outcomes. No such study has been reported in India yet to the best of our knowledge.

Purpose The main aim of this article was to evaluate the efficacy and safety of transcatheter GAE in relieving knee pain in patients with mild-to-moderate OA.

Materials and Methods Ten patients with radiographic knee OA and moderate-to-severe pain refractory to conservative therapy were enrolled in a prospective observational study. GAE was performed with 100 to 300-μm spherical particles. Patients were assessed with magnetic resonance imaging at the baseline. Visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were used to assess pain and disability respectively at the baseline, 1 month, and 3 months. Clinical success was asserted by the downstaging of VAS and WOMAC scores. Adverse events were recorded at all-time points. Descriptive and inferential statistics have been performed using SPSS. A p-Value less than 0.05 was considered statistically significant.

Results Embolization of at least 1 genicular artery was achieved in all the patients (100%). Clinical success was demonstrated in 08 (80%) of the patients. Median VAS reduced from 07 at baseline to 3.5 at 3-month follow-up (p < 0.001). Median WOMAC score improved from 53 to 23.50 at 3-month follow-up (p < 0.001). Minor complications were seen in two patients in the form of puncture site hematoma and mild petechial spots over the knee.

Conclusion Our pilot study demonstrates GAE as a safe and efficacious procedure to treat knee pain secondary to OA. Further randomized comparative studies with a larger sample size are needed to determine the true treatment effect versus the placebo effect.
Gastrointestinal Dysfunction in Genetically Defined Neurodevelopmental Disorders
Authors: Davidson Elizabeth A. , Holingue Calliope , Jimenez-Gomez Andres , Dallman Julia E. , Moshiree Baharak
Published: August 2023

Gastrointestinal symptoms are common in most forms of neurodevelopment disorders (NDDs) such as in autism spectrum disorders (ASD). The current patient-reported outcome measures with validated questionnaires used in the general population of children without NDDS cannot be used in the autistic individuals. We explore here the multifactorial pathophysiology of ASD and the role of genetics and the environment in this disease spectrum and focus instead on possible diagnostics that could provide future objective insight into the connection of the gut-brain-microbiome in this disease entity. We provide our own data from both humans and a zebrafish model of ASD called Phelan-McDermid Syndrome. We hope that this review highlights the gaps in our current knowledge on many of these profound NDDs and that it provides a future framework upon which clinicians and researchers can build and network with other interested multidisciplinary specialties.
Lipofilling—A Regenerative Alternate for Remodeling Burn Scars: A Clinico-Immunohistopathological Study
Authors: Jatin Bhojani , Karki Durga , Ahluwalia Charanjeet , Muthukumar Vamseedharan , Karki Divyanjali
Published: August 2023

Introduction Any injury involving the dermis will lead to scarring. Scar tissue can cause functional limitations, cosmetic impairments, pain, and itch. Adipose-derived stem cells have also been shown to play a role in scar modulation. This study evaluates changes in lipofilled scar over the period of time and compares it with non-lipofilled scar tissue.

Materials and Methods A prospective case–control study with intraindividual follow-up was performed on 30 adult patients with post-burn scars from November 2016 to May 2019. Clinical, histopathological, and immunohistochemical parameters were assessed among the case and control regions of the scar.

Results Mean age of the study population was 30.6 years. The duration of the scar included in this study ranged from 1 to 28 years, with a mean duration of 5.91 years. There was a significant reduction in pain, itch, stiffness, and an increase in the pliability of the scar, and a substantial improvement in the modified Vancouver Scar Score in the lipofilled group. In histopathological analysis, the case group showed organized parallel collagen fibers, a significant reduction in melanocytes, improvement in vascularity, and a significantly increased amount of collagen fibers at the reticular dermis. Immunohistochemical analysis indicated new cell synthesis in the scar tissue and reduced melanocytes.

Conclusion The remodeling effect of adipocyte-derived stem cells is long-lasting, and there is a gradual improvement in most of the parameters. Lipofilling has regenerative capacity, which leads to the improved overall appearance of scar and improvement at the cellular level.
A Prospective Observational Study of Diagnostic Reliability of Semiquantitative and Quantitative High b-Value Diffusion-Weighted MRI in Distinguishing between Benign and Malignant Lung Lesions at 3 Tesla
Authors: Mohakud Sudipta , Das Rasmibala , Bag Nerbadyswari D. , Mohapatra Prasanta R. , Mishra Pritinanda , Naik Suprava
Published: August 2023

Aim The aim of this study was to evaluate the usefulness of high b-value diffusion-weighted imaging (DWI) to differentiate benign and malignant lung lesions in 3 Tesla magnetic resonance imaging (MRI).

Materials and Methods Thirty-one patients with lung lesions underwent a high b-value (b= 1000 s/mm 2) DW MRI in 3 Tesla. Thirty lesions were biopsied, followed by histopathological analysis, and one was serially followed up for 2 years. Statistical analysis was done to calculate the sensitivity, specificity, and accuracy of different DWI parameters in distinguishing benign and malignant lesions. Receiver operating characteristic (ROC) curves were used to determine the cutoff values of different parameters.

Results The qualitative assessment of signal intensity on DWI based on a 5-point rank scale had a mean score of 2.71 ± 0.75 for benign and 3. 75 ± 0.60 for malignant lesions. With a cutoff of 3.5, the sensitivity, specificity, and accuracy were 75, 86, and 77.6%, respectively. The mean ADC min (minimum apparent diffusion coefficient) value of benign and malignant lesions was 1. 49 ± 0.38 × 10-3 mm 2/s and 1.11 ± 0.20 ×10-3 mm 2/s, respectively. ROC curve analysis showed a cutoff value of 1.03 × 10-3 mm 2/s; the sensitivity, specificity, and accuracy were 87.5, 71.4, and 83.3%, respectively. For lesion to spinal cord ratio and lesion to spinal cord ADC ratio with a cutoff value of 1.08 and 1.38, the sensitivity, specificity, and accuracy were 83.3 and 87.5%, 71.4 and 71.4%, and 80.6 and 83.8%, respectively. The exponential ADC showed a low accuracy rate.

Conclusion The semiquantitative and quantitative parameters of high b-value DW 3 Tesla MRI can differentiate benign from malignant lesions with high accuracy and make it a reliable nonionizing modality for characterizing lung lesions.
Early versus Standard Weight Bearing Following Operative Treatment of Tibial Plateau Fractures: Do We Really Have to Wait So Long?
Authors: Heiman Erick , Menken Luke G. , Tang Alex , Vialonga Mason , Jankowski Jaclyn M. , Liporace Frank A. , Yoon Richard S.
Published: August 2023

Postoperative management of tibial plateau fractures classically involves a prolonged period between 10 and 12 weeks of nonweight bearing or partial weight bearing. In recent years, there has been some support for earlier weight-bearing protocols although this remains controversial. The goal of this study was to investigate the difference in outcomes between early weight-bearing (EWB) and traditional weight-bearing (TWB) protocols. This investigation is a retrospective review of 92 patients treated with open reduction and internal fixation of tibial plateau fractures at a single institution, from August 2018 to September 2020. Subjects were divided into EWB (< 10 weeks) and traditional nonweight bearing groups (≥ 10 weeks). Key outcome measures collected include injury classification, mechanism of injury, surgical fixation method, bone grafting, time to full weight bearing, radiographic time to union, range-of-motion, all-cause complications, and subsidence at an average follow-up time of 1 year. The EWB group had an earlier average time to weight bearing versus the TWB group (6.5 ± 1.4 vs. 11.8 ± 2.3 weeks, p < 0.0001). There was no difference in the classification of fractures treated between the two groups, with Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association B3 fractures the most common in the EWB group, and C3 fractures the most common in the TWB group. Radiographic time to union was no different between the two groups (93.5 ± 53.7 days for EWB vs. 103.7 ± 77.6 days for TWB, p = 0.49). There was no significant difference in complication rates or subsidence. Following operative treatment of tibial plateau fractures, patients who underwent a weight-bearing protocol earlier than 10 weeks were able to recover faster with similar outcomes and complications compared with patients who started weight bearing after 10 weeks or more.

Level of Evidence III.
Expression of CD44 in Head and Neck Squamous Cell Carcinoma—An In-Silico Study
Authors: Kavitha Loganathan , Vijayashree Priyadharsini Jayaseelan , Kattula Deepthi , Rao Umadevi Krishna Mohan , Balaji Srikanth Rajabather , Kuzhalmozhi Manogaran , Ranganathan Kannan
Published: August 2023

Introduction CD44, a multistructural and multifunctional transmembrane glycoprotein, is a promising cancer stem cell (CSC) marker that regulates the properties of CSCs, including self-renewal, tumor initiation, and metastasis, and confers resistance to chemotherapy and radiotherapy. The aim of the present study was to evaluate the gene and protein expression of CD44 and explore its prognostic value in head and neck squamous cell carcinoma (HNSCC).

Methodology The present observational study employs computational tools for analysis. The Cancer Genome Atlas Head-Neck Squamous Cell Carcinoma dataset (520 primary HNSCC and 44 normal tissues) from the University of Alabama at Birmingham Cancer platform was used to study the association of CD44 mRNA transcript levels with various clinicopathological characteristics of HNSCC including age, gender, tumor grade, tumor stage, human papillomavirus (HPV) status, p53 mutation status, and overall survival. The CD44 protein expression in HNSCC and normal tissues was ascertained using the National Cancer Institute's Clinical Proteomic Tumor Analysis Consortium Head-and-Neck cancer dataset (108 primary HNSCC and 71 normal tissues).

Results CD44 mRNA transcript and protein expression levels were significantly higher in HNSCC tissues than in normal tissues, and high CD44 expression was correlated with poor survival. CD44 was upregulated in Stage 1 and Grade 2 HNSCC compared with other stages and grades. Overexpression of CD44 was observed in HPV-negative and TP53-positive mutant status in HNSCC.

Conclusion The pleiotropic roles of CD44 in tumorigenesis urge the need to explore its differential expression in HNSCC. The study concludes that CD44 can be a potential diagnostic and prognostic biomarker for HNSCC and offer new molecular targets for CD44-targeted therapy for cancer management.
Oscillations of the total kinematic momentum vector for viscous fluid dynamics in pipes of arbitrary section
Authors: Bogoyavlenskij Oleg
Published: August 2023

We derive the oscillatory exact solutions to the Navier–Stokes equations that describe z-invariant viscous fluid flows in a general cylindrical pipe C=D×ℝ1 with section D having an arbitrary geometry and a piece-wise smooth boundary ∂D. Exact viscous fluid flows are presented that satisfy the no-slip boundary condition at the pipe's boundary ∂D×ℝ1 and have an arbitrary number of oscillations of the total kinematic momentum vector on any given interval of time [T1,T2]. The stability of the oscillations with respect to small perturbations of infinitely many parameters is proven. The new method for the generation of a hierarchy of exact solutions with oscillating kinematic momentum is developed. Exact solutions to the Navier–Stokes equations without external forces (in addition to the friction forces at the pipes's boundary ∂D×ℝ1) are derived, which have any number of oscillations of the average shift of viscous fluid.
Collisional-like dissipation in collisionless plasmas
Authors: Bandyopadhyay Riddhi , Yang Yan , Matthaeus William H. , Parashar Tulasi N. , Roytershteyn Vadim , Chasapis Alexandros , Gershman D. J. , Giles B. L. , Burch J. L.
Published: August 2023

When collisions are strong in a magnetized plasma, standard closures provide simple representations of dissipation in terms of coefficients of viscosity and resistivity. In the opposite limit of weak collisions, the analogous physical effects that lead to dissipation are present, but the simple approximations to describe them, the closures, are not available in general. But how different are these relationships when collisions are absent? Here, we inquire as to whether the collisionless case admits statistical relationships analogous to the viscous and resistive closures found in collisional plasma. We employ kinetic particle-in-cell simulations of proton–electron plasma as well as in situ observations from the Magnetospheric Multiscale Mission, to examine analogous viscous-like and resistive-like scaling in the weakly collisional regime. Rather surprisingly, we find that, on average, the collisionless cases do exhibit dissipation behavior very similar to the collisional plasmas. It is of theoretical significance that the relationships found are statistical and not deterministic as they are when collisional closures are enforced.
Dynamic and static properties of quantum Hall and harmonic oscillator systems on the non-commutative plane
Authors: Nessi Nicolás , Sourrouille Lucas
Published: August 2023

We study two quantum mechanical systems on the noncommutative plane using a representation independent approach. First, in the context of the Landau problem, we obtain an explicit expression for the gauge transformation that connects the Landau and the symmetric gauge in noncommutative space. This lead us to conclude that the usual form of the symmetric gauge A⃗=−β2Ŷ,β2X̂, in which the constant β is interpreted as the magnetic field, is not true in noncommutative space. We also be able to establish a precise definition of β as a function of the magnetic field, for which the equivalence between the symmetric and Landau gauges is held in noncommutative plane. Using the symmetric gauge, we obtain results for the spectrum of the quantum Hall system, its transverse conductivity in the presence of an electric field, and other static observables. These results amend the literature on quantum Hall effect in the noncommutative plane in which the incorrect form of the symmetric gauge, in noncommutative space, is assumed. We also study the non-equilibrium dynamics of simple observables for this system. On the other hand, we study the dynamics of the harmonic oscillator in non-commutative space and show that, in general, it exhibits quasi-periodic behavior, in striking contrast with its commutative version. The study of dynamics reveals itself as a most powerful tool to characterize and understand the effects of non-commutativity.
Magnetic octupole domain evolution and domain-wall structure in the noncollinear Weyl antiferromagnet Mn3Ge
Authors: Wu Mingxing , Kondou Kouta , Nakatani Yoshinobu , Chen Taishi , Isshiki Hironari , Higo Tomoya , Nakatsuji Satoru , Otani Yoshichika
Published: August 2023

Antiferromagnets with the intrinsic advantages of terahertz spin dynamics and negligible stray fields have been extensively studied for spintronic applications. In particular, spintronic research on antiferromagnets has expanded its focus from collinear to noncollinear Weyl antiferromagnets and discovered that Mn3X (X = Sn, Ge) produces substantial magneto-electric responses. Therefore, noncollinear antiferromagnets could be an ideal spintronic platform. Exploring the domain-wall features in Mn3X is, on the other hand, essential for spintronic device engineering. Here, we report an in-depth study on magnetic octupole domain evolution and domain-wall structure with a choice of Mn3Ge single crystal. Our magneto-optical imaging and the anomalous Hall measurements elucidate the nontrivial magnetic octupole domain nucleation, domain-wall propagation, and pinning behaviors. Moreover, combining the micromagnetic simulation, we reveal that Bloch- and Néel-like walls coexist in bulk with comparable sizes and energy densities. Our findings promote understanding the magnetic octupole domain-wall physics and designing domain-wall-based spintronic devices.
On the polytropic coefficient of negative ions for modeling the sheath and presheath of electronegative plasmas
Authors: Schiesko L. , Lishev St. , Revel A. , Carbone E. , Minea T.
Published: August 2023

The fluid description is widely used for the multi-dimensional modeling of low temperature plasmas with complex chemistries due to their relative low computational cost. It relies, however, on a series of simplifying assumptions and some truncation of the moment equations for describing the non-equilibrium between the electrons, positive ions, negative ions, and the neutrals. In this paper, the classical assumption of isothermal negative ions is revisited for electronegative plasmas and, more particularly, for the fluid modeling of the transition between the plasma and its sheath. To do so, and in contrast to previous studies, the energy balance equation for the negative ions is also computed, and it allows us to derive the polytropic coefficient γ of the negative ions in addition to one of the positive ions. Strong variations in the sheath and presheath of the negative ions temperature and their polytropic coefficient are observed. The polytropic coefficient is shown to be a strongly varying function of space having for consequence that the negative ions are isothermal only in a very narrow extension of the presheath. For the case considered in this paper, both positive and negative ion flows are nearly adiabatic at the sheath-edge and become adiabatic inside the sheath. This paper shows that classical fluid modeling assumptions need to be verified for each system under consideration, most particularly while modeling the transition from plasma to a wall.
From Babylonian lunar observations to Floquet multipliers and Conley–Zehnder indices
Authors: Aydin Cengiz
Published: August 2023

In 1878, Hill found numerically, in his limiting case of the restricted three-body problem, the so-called Hill’s lunar problem, a planar direct periodic orbit with a period of one synodic month. By virtue of the spatial system’s invariance under a symplectic involution, whose fixed point set corresponds to the planar problem, we can assign to Hill’s orbit planar and spatial Floquet multipliers and planar and spatial Conley–Zehnder indices. We show that these have deep astronomical significance because, on the one hand, we relate the anomalistic month to the planar Floquet multipliers and the planar Conley–Zehnder index. On the other hand, we relate the draconitic month to the spatial Floquet multipliers and the spatial Conley–Zehnder index. Knowledge of this lunar month dates back to the Babylonians, who lived until around 500 BCE. In order to determine the indices, we analyze analytically the bifurcation procedure of the fundamental families of planar direct and retrograde periodic orbits (traditionally known as families g and f) from the rotating Kepler problem for very low energies.
Multiscale computational modeling of the effects of 2’-deoxy-ATP on cardiac muscle calcium handling
Authors: Hock Marcus T. , Teitgen Abigail E. , McCabe Kimberly J. , Hirakis Sophia P. , Huber Gary A. , Regnier Michael , Amaro Rommie E. , McCammon J. Andrew , McCulloch Andrew D.
Published: August 2023

2’-Deoxy-ATP (dATP), a naturally occurring near analog of ATP, is a well-documented myosin activator that has been shown to increase contractile force, improve pump function, and enhance lusitropy in the heart. Calcium transients in cardiomyocytes with elevated levels of dATP show faster calcium decay compared with cardiomyocytes with basal levels of dATP, but the mechanisms behind this are unknown. Here, we design and utilize a multiscale computational modeling framework to test the hypothesis that dATP acts on the sarcoendoplasmic reticulum calcium-ATPase (SERCA) pump to accelerate calcium re-uptake into the sarcoplasmic reticulum during cardiac relaxation. Gaussian accelerated molecular dynamics simulations of human cardiac SERCA2A in the E1 apo, ATP-bound and dATP-bound states showed that dATP forms more stable contacts in the nucleotide binding pocket of SERCA and leads to increased closure of cytosolic domains. These structural changes ultimately lead to changes in calcium binding, which we assessed using Brownian dynamics simulations. We found that dATP increases calcium association rate constants to SERCA and that dATP binds to apo SERCA more rapidly than ATP. Using a compartmental ordinary differential equation model of human cardiomyocyte excitation-contraction coupling, we found that these increased association rate constants contributed to the accelerated rates of calcium transient decay observed experimentally. This study provides clear mechanistic evidence of enhancements in cardiac SERCA2A pump function due to interactions with dATP.
Ultra-broadband low-frequency high-efficiency acoustic energy harvesting with metamaterial-enhanced loudspeakers
Authors: Peng Xiuyuan , Li Junfei , Cummer Steven A.
Published: August 2023

Acoustic energy harvesters (AEHs) open up opportunities to recycle noise waste and generate electricity. They provide potential power solutions to a wide range of sensors. However, the practicality of AEHs has long been limited by their narrow bandwidths and low efficiencies. In this study, we present an ultra-broadband AEH and a highly efficient AEH that transforms sound energy into usable electrical power. Our broadband device comprises an electrodynamic loudspeaker driver and an optimized acoustic metamaterial matching layer and is capable of converting 7.6% to 15.1% of total incident sound energy from 50 to 228 Hz. Moreover, we demonstrate that by replacing the loudspeaker surround with a lower-loss material such as PDMS, the energy conversion rate can be significantly increased to 67%. The proposed broadband AEH has a fractional bandwidth eight times the state-of-the-art, while the proposed highly efficient AEH has a peak efficiency three times the state-of-the-art. The outstanding performance makes our designs cost-effective and scalable solutions for noise reduction and power generation.
Arbitrarily high-order accurate simulations of compressible rotationally constrained convection using a transfinite mapping on cubed-sphere grids
Authors: Chen Kuangxu , Liang Chunlei , Wan Minping
Published: August 2023

We present two major improvements over the Compressible High-ORder Unstructured Spectral difference (CHORUS) code published in Wang et al., “A compressible high-order unstructured spectral difference code for stratified convection in rotating spherical shells,” J. Comput. Phys. 290, 90–111 (2015). The new code is named CHORUS++ in this paper. Subsequently, we perform a series of efficient simulations for rotationally constrained convection (RCC) in spherical shells. The first improvement lies in the integration of the high-order spectral difference method with a boundary-conforming transfinite mapping on cubed-sphere grids, thus ensuring exact geometric representations of spherical surfaces on arbitrary sparse grids. The second improvement is on the adoption of higher-order elements (sixth-order) in CHORUS++ vs third-order elements for the original CHORUS code. CHORUS++ enables high-fidelity RCC simulations using sixth-order elements on very coarse grids. To test the accuracy and efficiency of using elements of different orders, CHORUS++ is applied to a laminar solar benchmark, which is characterized by columnar banana-shaped convective cells. By fixing the total number of solution degrees of freedom, the computational cost per time step remains unchanged. Nevertheless, using higher-order elements in CHORUS++ resolves components of the radial energy flux much better than using third-order elements. To obtain converged predictions, using sixth-order elements is 8.7 times faster than using third-order elements. This significant speedup allows global-scale fully compressible RCC simulations to reach equilibration of the energy fluxes on a small cluster of just 40 cores. In contrast, CHORUS simulations were performed by Wang et al. on supercomputers using approximately 10 000 cores. Using sixth-order elements in CHORUS++, we further carry out global-scale solar convection simulations with decreased rotational velocities. Interconnected networks of downflow lanes emerge and surround broader and weaker regions of upflow fields. A strong inward kinetic energy flux compensated by an enhanced outward enthalpy flux appears. These observations are all consistent with those published in the literature. Furthermore, CHORUS++ can be extended to magnetohydrodynamic simulations with potential applications to the hydromagnetic dynamo processes in the interiors of stars and planets.
Field-free spin-orbit-torque switching of a single ferromagnetic layer with fourfold in-plane magnetic anisotropy
Authors: Han Kyoul , Lee Kyung Jae , Lee Sanghoon , Liu Xinyu , Dobrowolska M. , Furdyna Jacek K.
Published: August 2023

We present the observation of field-free spin-orbit-torque (SOT) switching of magnetization in a ferromagnetic semiconductor (Ga,Mn)As film with four-fold in-plane magnetic anisotropy. Magnetization switching is demonstrated between two orthogonal in-plane easy axes through planar Hall resistance measurements as a current is scanned in the absence of a magnetic field. The chirality of the switching of the current hysteresis loop is consistent with SOT arising from spin polarization caused by Dresselhaus- and Rashba-type spin-orbit-induced effective magnetic fields in the (Ga,Mn)As film. The chirality of magnetization switching can be reversed either by changing the direction of the initial magnetization or by applying a constant external magnetic field bias. The SOT magnetization switching between two states was consistently repeated by applying sequential current pluses with alternating polarities, indicating the potential for developing a field-free SOT device.
Determining the flow transition from laminar to turbulence using simple spin-echo magnetic resonance techniques
Authors: Richard Sebastian J. , Balcom Bruce J. , Newling Benedict
Published: August 2023

We have recently introduced a methodology to determine the average velocity and flow behavior index of laminar pipe flow of a power-law fluid using simple magnetic resonance (MR) techniques. In general, MR techniques are noninvasive and capable of working on optically opaque fluids. Knowledge of the average velocity and flow behavior index provides the information needed to reconstruct the flow velocity profile. However, as the flow velocity increases, the flow will begin to develop turbulence. For pipe flow of a particular fluid, the velocity profile is flatter in the center of the pipe at turbulent flow rates compared with laminar flow. An effective flow behavior index can approximate the time-averaged velocity profile, as the Reynolds number increases, as a fluid transitions from laminar to turbulent flow. Here, we show the results of testing the utility of such a simplification in monitoring that transition. For the present study, Reynolds numbers ranged from approximately 490 to 6800, which corresponds to flow rates of 200 to 2750 ml/min and average velocity of 5 to 80 cm/s. We found that visual inspection of the data would be sufficient to determine the state of the flow. With some external knowledge of the flow rate, the shape of the time-averaged velocity profile and eddy diffusivity can be estimated (and potentially also an average fluid particle acceleration).
On the attitude stability of flying dandelion seeds
Authors: Qin Lang , Jian Zhen , Xu Yeyin , Ma Lifeng
Published: August 2023

Dandelion seeds possess a complex three-dimensional structure and a self-adapted flying ability. To understand this fascinating flight mechanism, a three-dimensional umbrella-shaped model imitating dandelion seeds is proposed. The effects of folding angle and flow velocity on the dandelion drag force during their descent are studied, and it is found that the larger folding angle results in a smaller drag coefficient. Four different vortex structures are revealed depending on the folding angle. The effect of crosswind disturbances on the attitude stability of dandelions is also investigated by changing folding angles. It is found that dandelions with larger folding angles have better attitude stability. The proposed model suggests that when the folding angle is between 20° and 40°, the dandelion seeds might have a good balance between the drag force and attitude stability, which ensures a broad self-adapted flying ability.
Effect of slip on the linear stability of the rotating disk boundary layer
Authors: Thomas Christian , Alveroğlu Burhan , Stephen Sharon O. , Al-Malki Mushrifah A. S. , Hussain Zahir
Published: August 2023

The linear stability of the rotating disk boundary layer with surface roughness is investigated. Surface roughness is modeled using slip boundary conditions [M. Miklavčič and C. Y. Wang, Z. Angew. Math. Phys. 55, 235–246 (2004)], which establish concentric grooves, radial grooves, and isotropic roughness. The effect on the stationary crossflow and Coriolis instabilities is analyzed by applying slip conditions to the undisturbed flow and linear disturbances. This analysis builds on the work of Cooper et al. [Phys. Fluids 27, 014107 (2015)], who modeled slip effects on the base flow but applied the no-slip condition to the linear perturbations. Neutral stability curves and critical parameter settings for linearly unstable behavior are computed for several radial and azimuthal slip length settings. The application of slip on the linear disturbances has a significant impact on the flow stability. In particular, the Coriolis instability undergoes considerable destabilization in the instance of concentric grooves (i.e., radial slip) and radial grooves with sufficiently large azimuthal slip lengths. In addition, concentric grooves destabilize the crossflow instability when the radial slip length is small. Moreover, in the instance of isotropic roughness, the stabilizing effect is markedly less than the observations of Cooper et al. [Phys. Fluids 27, 014107 (2015)]. Finally, an energy analysis is undertaken to ascertain the physical mechanisms brought about by surface roughness.
Experimental study on the air cushion effect during the flooding process of a damaged ship cabin
Authors: Liu Wen-Bin , Ming Fu-Ren , Chen Hao , Zhang A-Man
Published: August 2023

In the rapid flooding process of a damaged ship, the air trapped in a damaged cabin will be compressed into an air cushion, which causes the air cushion effect (ACE). The ACE has a significant influence on the flooding process of an airtight cabin. In this paper, a three-cabin model is designed according to a parent ship, and a series of model experiments are carried out. First, the air-tightness ratio is defined by combining various air vents with different opening areas, and the flooding model experiments of different air-tightness ratios are carried out. The heeling and trimming angles of the model, the overpressure of the air cushion, and the water height inside the flooding cabin are recorded and analyzed, and the characteristics of ACE are summarized. Second, different forms of air vents with a same air-tightness ratio are designed, and the influence of the air vent distribution on the flooding process is analyzed. With the quasi-static method used for comparisons, the numerical results are compared with the experimental ones to check the effectiveness of the quasi-static method on the rapid flooding problems. The research on ACE can guide the design of ship subdivisions and provide a reference for the rescue of shipwreck accidents.
Grazing capacity determination in short-term and long-term scales using MODIS and Sentinel-2 data in the southern rangelands of Zagros, Iran
Authors: Jafari F. , Jafari R. , Bashari H.
Published: August 2023

Mapping and updating grazing capacity are necessary due to spatio-temporal variations of production in rangelands as a result of climatic and management changes. This study utilised short- and long-term grazing capacity mapping and monitoring by using satellite images in the rangelands of southern Zagros, Iran. In 2018, production of 16 rangeland types was estimated at spatial scales of 250 and 10 m from MODIS and Sentinel-2 images, and validated with field production data measured at 185 sampling sites through the R2 coefficient of determination. The production maps, along with the parameters of allowable utilisation of rangeland plant species, animal grazing area, animal daily requirement and length of grazing period, were used to calculate grazing capacity. In addition, the effect of climatic fluctuations on grazing capacity was investigated using the Standard Index of Annual Precipitation (SIAP) index from 2009 to 2018. The production obtained from satellite images varied between 2.4 and 393.2 kg ha−1 in 2018. The high correlation (80%) between image production maps and field measurements, as well as the significance of these relationships in all rangeland types (P < 0.05), allowed grazing capacity estimation by using satellite-based production. The minimum and maximum grazing capacities in a 100-day period were 1809 and 297 146 animal units (AU) respectively, in 258 387 ha. Grazing capacity monitoring from 2009 to 2018 showed that during a drought period, AUs were about 0.7 ha−1 below those in years of above-average rainfall. Use of satellite remote-sensing with different spatio-temporal scales therefore appears capable of mapping and monitoring grazing capacity, and can be used as a management tool by rangeland owners and related organisations.
Dynamical heterogeneity in active glasses is inherently different from its equilibrium behavior
Authors: Paul Kallol , Mutneja Anoop , Nandi Saroj Kumar , Karmakar Smarajit
Published: August 2023

Activity-driven glassy dynamics, while ubiquitous in collective cell migration, intracellular transport, dynamics in bacterial and ant colonies, etc., also extends the scope and extent of the as-yet mysterious physics of glass transition. Active glasses are hitherto assumed to be qualitatively similar to their equilibrium counterparts at an effective temperature,

T

eff

. Here, we combine large-scale simulations and an analytical mode-coupling theory (MCT) for such systems and show that, in fact, an active glass is inherently different from an equilibrium glass. Although the relaxation dynamics can be equilibrium-like at a

T

eff

, effects of activity on the dynamic heterogeneity (DH), which is a hallmark of glassy dynamics, are quite nontrivial and complex. With no preexisting data, we employ four distinct methods for reliable estimates of the DH length scales. Our work shows that active glasses exhibit dramatic growth of DH and systems with similar relaxation times, and thus,

T

eff

can have widely varying DH. To theoretically study DH, we extend active MCT and find good qualitative agreement between the theory and simulation results. Our results pave avenues for understanding the role of DH in glassy dynamics and can have fundamental significance even in equilibrium.
Discontinuous instabilities in disordered solids
Authors: Xu Ding , Zhang Shiyun , Liu Andrea J. , Nagel Sidney R. , Xu Ning
Published: August 2023

Under a sufficiently large load, a solid material will flow via rearrangements, where particles change neighbors. Such plasticity is most easily described in the athermal, quasistatic limit of zero temperature and infinitesimal loading rate, where rearrangements occur only when the system becomes mechanically unstable. For disordered solids, the instabilities marking the onset of rearrangements have long been believed to be fold instabilities, in which an energy barrier disappears and the frequency of a normal mode of vibration vanishes continuously. Here, we report that there exists another, anomalous, type of instability caused by the breaking of a “stabilizing bond,” whose removal creates an unstable vibrational mode. For commonly studied systems, such as those with harmonic finite-range interparticle interactions, such “discontinuous instabilities” are not only inevitable, they often dominate the modes of failure. Stabilizing bonds are a subset of all the bonds in the system and are prevalent in disordered solids generally. Although they do not trigger discontinuous instabilities in systems with vanishing stiffness at the interaction cutoff, they are, even in those cases, local indicators of incipient mechanical failure. They therefore provide an accurate structural predictor of instabilities not only of the discontinuous type but of the fold type as well.
Strengthening of wire arc additive manufactured aluminium alloy through interlayer rotary friction processing
Authors: Yu Runzhen , Yu Shengfu , Wang Zhimin , Yu Guozhi
Published: August 2023

To eliminate porosity and refine the grains in aluminium alloys fabricated via wire arc additive manufacturing (WAAM), a novel strengthening method – robotic rotary friction processing (RFP) – was introduced. The feasibility of RFP was assessed by processing the deposited beads under various average peak loads. During RFP, a rotating tool pressed the deposited beads to induce sufficient plastic deformation. After 3.5 kN-RFP, the WAAM densification ratio was improved to >99.5%, and pores were completely closed and eliminated owing to compression deformation and sub-grains bonding. The processed deposits exhibited effective grain refinement and high-density dislocation entanglement, which led to 22.8% and 34.2% improvements in the horizontal and vertical tensile strengths, respectively. Furthermore, the strengthening mechanism of RFP on deposited metals was clarified.
Continuous phase transition of the de Sitter spacetime with charged black holes and cloud of strings and quintessence*
Authors: Zhen 甄 Hai-Long 海龙 , Du 杜 Yun-Zhi 云芝 , Li 李 Huai-Fan 怀繁 , Li 李 Xin-Ping 新平 , Zhang 张 Li-Chun 丽春
Published: August 2023

Recently, some meaningful results have been obtained by studying the phase transition, critical exponents, and other thermodynamical properties of different black holes. Especially for the Anti-de Sitter (AdS) black holes, their thermodynamical properties nearby the critical point have attracted considerable attention. However, there exists little work on the thermodynamic properties of the de Sitter (dS) spacetime with black holes. In this paper, based on the effective thermodynamical quantities and the method of the Maxwell's equal-area law, we explore the phase equilibrium for the de Sitter spacetime with the charged black holes and the cloud of string and quintessence (i.e., C-dSSQ spacetime). The boundaries of the two-phase coexistence region in both

and

diagrams are obtained. The coexistent curve and the latent heat of phase transition for this system are also investigated. Furthermore, we analyze the effect of parameters (the state parameter ω and the ratio of two horizon radii

/

) on the two-phase coexistence region boundary. The results indicate that the phase transition in C-dSSQ spacetime is analogous to that in a van der Waals fluid (vdw) system, which is determined by the electrical potential at the horizon. These results are helpful for understanding the basic properties of black holes and are also of great value for the establishment of quantum gravity.
Fast neutron radiography detector with polyethylene converter and MCP: development and performance evaluation
Authors: Ma Zhan-Wen , Bai Xiao-Hou , Liu Chang-Qi , Hu Zhi-Ming , Huang Chang , Wang Jun-Run , Lu Xiao-Long , Wei Zheng , Zhang Yu , Yao Ze-En
Published: August 2023

We present a new position-sensitive fast neutron detector for 14 MeV fast neutron radiography, comprising a high-density polyethylene converter, a micro-channel plate (MCP), a P43 phosphor screen, a reflection mirror, and a CCD camera. Experimental tests are conducted using a DT neutron generator at CIAE, with different samples and a knife-edge measurement used to determine overall image resolution. Results show that the detector is feasible for fast neutron radiography, producing a fast neutron image with a neutron
flux of ∼ 3.22 × 104 n · s-1 · cm-2 
and 120 s exposure time. Our study demonstrates the potential of this detector for use in fast neutron radiography applications.