bluuebunny/crossref_metadata_2025 huggingface dataset:
Achalasia Following SARS-CoV-2 Infection: A Case Report and Review of Literature
Authors: Huang Jianbin , Su Huang , Lin Jiejun , Zhu Fangchao , Jiang Xiaofen , Pan Jie
Published: April 2024

Rationale The COVID-19 pandemic caused by the SARS-CoV-2 virus has led to health complications beyond respiratory symptoms, revealing multi-organ involvement, including potential gastrointestinal implications.

Patient Concerns We present a case of a 40-year-old female without any history of achalasia who developed symptoms of the condition following a confirmed SARS-CoV-2 infection. Unusually, multiple esophageal ulcers were identified, which are not typically associated with achalasia.

Diagnosis Achalasia and esophageal ulcers were confirmed through a series of examinations, including barium swallow, CT scan, and upper endoscopy. Furthermore, immunohistochemical staining of esophageal biopsy specimens revealed the presence of the SARS-CoV-2 spike protein, suggesting direct viral involvement.

Interventions The patient was treated with calcium channel blockers and proton pump inhibitors and later underwent a peroral endoscopic myotomy (POEM) procedure following the resolution of her COVID-19 infection.

Outcome After the POEM procedure, the patient made a good recovery.

Lessons This case underscores the potential for SARS-CoV-2 to trigger gastrointestinal complications and emphasizes the need for ongoing patient management and further research into the long-term implications of COVID-19. Despite the single-case nature of this report, it contributes to the expanding understanding of the diverse and multi-systemic impact of COVID-19.
Effects of transcranial direct current stimulation and sensorimotor training in anterior cruciate ligament patients: a sham-controlled pilot study
Authors: Reuter Sven , Lambert Christophe , Schadt Maja , Imhoff Andreas B. , Centner Christoph , Herbst Elmar , Stöcker Fabian , Forkel Philipp
Published: April 2024

Background Studies showed changes in the central nervous system in patients who sustained an anterior cruciate ligament tear. There is a lack of evidence regarding the effectiveness of transcranial direct-current stimulation in such patients.

Methods A sham-controlled randomised study. One group of patients (n = 6) underwent 6 weeks of sensorimotor training after an anterior cruciate ligament tear during transcranial direct-current stimulation. The stimulation consisted of 20 minutes (3 sessions/week; 2 weeks) of 2 mA anodal transcranial direct-current stimulation over the primary motor and premotor cortex. The second group (n = 6) received sham stimulation with 6 weeks of sensorimotor training. Centre of pressure deviations in the medio-lateral and anterior-posterior direction and centre of pressure velocity were measured.

Results The results demonstrated a significant effect of sensorimotor training on the centre of pressure in medio-lateral and anterior-posterior direction (p=0.025) (p=0.03) in the leg in which an anterior cruciate ligament tear occurred. The type of training did not affect the results. Post-hoc tests showed no significant effect of training in the subgroups (p≥0.115).

Conclusion Sensorimotor training led to a decrease in sway of the centre of pressure in patients who sustained an anterior cruciate ligament tear, but the addition of anodal transcranial direct-current stimulation placed over the primary motor cortex did not potentiate the adaptive responses of the sensorimotor training.
Effects of Implementing a Routine Postpartum Fasting Blood Glucose on the Completion of the Gold Standard 2-Hour Oral Glucose Tolerance Test in Gestational Diabetics
Authors: Prior Alissa K. , Dolin Cara D. , Bender Whitney , Durnwald Celeste P. , Hamm Rebecca F.
Published: April 2024

Objective Rates of completion of the gold standard 2-hour oral glucose tolerance test (OGTT) for impaired glucose intolerance postpartum in patients with gestational diabetes mellitus (GDM) are consistently less than 50%. Screening tests performed prior to hospital discharge, including fasting blood glucose (FBG) to detect persistent hyperglycemia, have been investigated. We lack evidence, however, on whether implementation of routine postpartum FBG impacts the likelihood of obtaining the routine 2-hour OGTT. We sought to retrospectively compare the rates of completion of the 2-hour OGTT pre- and postimplementation of a routine FBG screen.

Study Design We performed a single-center retrospective cohort study comparing the completion of the 2-hour OGTT pre- and postimplementation of a routine FBG screen. Our primary outcome was the completion of the postpartum OGTT. Bivariate analyses assessed associations between demographic and preinduction clinical characteristics by pre- and post-implementation groups, as well as OGTT completion. Multivariable logistic regression was used to control for possible confounders. A sensitivity analysis was performed to account for the overlap with the coronavirus disease 2019pandemic.

Results In total, 468 patients met the inclusion and exclusion criteria. In our post-intervention group, 64% of patients completed a postpartum FBG. For our primary outcome, completion of the 2-hour OGTT significantly decreased in our postintervention group from 37.1 to 25.9% (p = 0.009), adjusted odds ratio (aOR): 0.62, confidence interval (CI): 0.41–0.92. This difference was no longer statistically significant when excluding patients during the pandemic, from 40.3 to 33.1% (p = 0.228), aOR: 0.76, CI: 0.455–1.27.

Conclusion Implementation of a routine FBG was associated with a negative impact on patients completing a 2-hour OGTT. The difference was no longer significant when excluding patients who would have obtained the OGTT during the pandemic, which may have been due to the smaller cohort. Future work should investigate patient perceptions of the FBG and its impact on their decision-making around the OGTT.

Key Points
Extended Composite Approach to Deep Plane Face Lifting with Deep Contouring of the Neck and the Nuances of Secondary and Tertiary Facelifting: Principles for Restoration of Natural Anatomy and Aesthetically Attractive Face and Neck Contour
Authors: Bray Dominic
Published: April 2024

Patients seek second facelifts either due to dissatisfaction with the primary procedure or years later after continued face and neck aging following successful first surgery. Previous surgical anatomical disruption, deformity of tension and vector, scar formation and skin excision compounded by the proliferation of historical energy-based skin treatments, thread lift procedures, and injectables make revision rhytidectomy a complex process of causal identification and surgical repair. Patients seeking revision due to dissatisfaction with a primary procedure, or worse visible deformity, have a heightened sense of anxiety which necessitates accurate diagnosis, careful examination, comprehensive documentation, and confidence in any planned secondary intervention as well as conservative expectation management. This article outlines the author's approach to identify the challenges posed and successfully perform secondary and revision rhytidectomy using a modified extended deep plane approach.
The Evolution of My Extended SMAS-Biplanar Deep Plane Facelift to a Composite Tissue Deep Plane Face and Neck Lift: Similarities and Differences
Authors: Perkins Stephen W. , Caniglia Alexander
Published: April 2024

In this article, Dr. Stephen W. Perkins, a seasoned facial plastic surgeon, presents his refined techniques in facelift surgery developed over four decades of practice. His evolution from traditional methods to the current composite tissue deep plane facelift is elucidated. His composite tissue deep plane facelift involves meticulous dissection and repositioning of the superficial musculoaponeurotic system (SMAS) and platysma in the deep plane, as well as incorporating his innovative “Perkins' Kelly clamp anterior platysmaplasty.” This technique, refined through years of experience, aims for natural, enduring results, crucially addressing patient concerns such as jowling and neck laxity. Long-term analysis reveals the advantages of Dr. Perkins' technique, particularly in achieving sustained cervicomental angle improvement for over a decade postoperatively. This article underscores the importance of understanding deep plane facelift techniques, distinguishing between different approaches, and tailoring surgical interventions to individual patient characteristics. Dr. Perkins' comprehensive approach, incorporating advancements in surgical technique and meticulous patient care protocols, exemplifies the goal of achieving natural, long-lasting facial rejuvenation.
Torticollis with Atlantoaxial Rotatory Subluxation in Children: A Clinical Review
Authors: Kempeneers Marinus A. , Buis Dennis R. , Feller Ricardo E. , Roosendaal Stefan D. , Slot K. Mariam , Wolf Nicole I. , Vandertop W. Peter
Published: April 2024

A small proportion of children with a sudden onset torticollis (“wry neck”) presents with an atlantoaxial rotatory subluxation, usually after mild trauma or recent head or neck infection. Torticollis is a clinical diagnosis and imaging is usually not indicated, though often performed in clinical practice. Atlantoaxial rotatory subluxation on imaging is often a physiological phenomenon in torticollis, and concomitant neurological symptoms are therefore rare. Treatment is primarily conservative, with analgesics, a rigid neck collar, and if needed benzodiazepines to counteract muscle spasms and anxiety. In case of treatment failure or chronic subluxation, cervical repositioning and fixation under general anesthesia may be considered. Surgical treatment is only indicated in a small percentage of patients with chronic refractory subluxation, concomitant cervical fractures, or congenital anomalies. Early diagnosis and treatment are important, since this is associated with a more successful conservative outcome than a prolonged approach.
Effect of optical diagnosis training on recognition and treatment of submucosal invasive colorectal cancer in community hospitals: a prospective multicenter intervention study
Authors: Meulen Lonne W.T. , Haasnoot Krijn J.C. , Vlug Marije S. , Wolfhagen Frank H.J. , Baven-Pronk Martine A.M.C. , van der Voorn Michael P.J.A. , Schwartz Matthijs P. , Vogelaar Lauran , de Vos tot Nederveen Cappel Wouter H , Seerden Tom C.J. , Hazen Wouter L. , Schrauwen Ruud W.M. , Alvarez-Herrero Lorenza , Schreuder Ramon-Michel , van Nunen Annick B. , Stoop Esther , de Bruin Gijs J. , Bos Philip , Marsman Willem A. , Kuiper Edith , de Bièvre Marc , Alderlieste Yasser A. , Roomer Robert , Groen John , Bigirwamungu-Bargeman Marloes , Siersema Peter D. , Elias Sjoerd G. , Masclee Ad A.M. , Moons Leon M.G. ,   on behalf of the OPTICAL-STAR study team and the Dutch T1 CRC Working Group
Published: April 2024

Background Recognition of submucosal invasive colorectal cancer (T1 CRC) is difficult, with sensitivities of 35 %–60 % in Western countries. We evaluated the real-life effects of training in the OPTICAL model, a recently developed structured and validated prediction model, in Dutch community hospitals.

Methods In this prospective multicenter study (OPTICAL II), 383 endoscopists from 40 hospitals were invited to follow an e-learning program on the OPTICAL model, to increase sensitivity in detecting T1 CRC in nonpedunculated polyps. Real-life recognition of T1 CRC was then evaluated in 25 hospitals. Endoscopic and pathologic reports of T1 CRCs detected during the next year were collected retrospectively, with endoscopists unaware of this evaluation. Sensitivity for T1 CRC recognition, R0 resection rate, and treatment modality were compared for trained vs. untrained endoscopists.

Results 1 year after e-learning, 528 nonpedunculated T1 CRCs were recorded for endoscopies performed by 251 endoscopists (118 [47 %] trained). Median T1 CRC size was 20 mm. Lesions were mainly located in the distal colorectum (66 %). Trained endoscopists recognized T1 CRCs more frequently than untrained endoscopists (sensitivity 74 % vs. 62 %; mixed model analysis odds ratio [OR] 2.90, 95 %CI 1.54–5.45). R0 resection rate was higher for T1 CRCs detected by trained endoscopists (69 % vs. 56 %; OR 1.73, 95 %CI 1.03–2.91).

Conclusion Training in optical recognition of T1 CRCs in community hospitals was associated with increased recognition of T1 CRCs, leading to higher en bloc and R0 resection rates. This may be an important step toward more organ-preserving strategies.
Sprint-inspired One-on-One Post-Go-Live Training Session (Mini-Sprint) Improves Provider Electronic Health Record Efficiency and Satisfaction
Authors: Chen July , Chi Wei Ning , Ravichandran Urmila , Solomonides Anthony , Trimark Jeffrey , Patel Shilpan , McNulty Bruce , Shah Nirav S. , Brown Stacy
Published: April 2024

Background Inefficient electronic health record (EHR) usage increases the documentation burden on physicians and other providers, which increases cognitive load and contributes to provider burnout. Studies show that EHR efficiency sessions, optimization sprints, reduce burnout using a resource-intense five-person team. We implemented sprint-inspired one-on-one post-go-live efficiency training sessions (mini-sprints) as a more economical training option directed at providers.

Objectives We evaluated a post-go-live mini-sprint intervention to assess provider satisfaction and efficiency.

Methods NorthShore University HealthSystem implemented one-on-one provider-to-provider mini-sprint sessions to optimize provider workflow within the EHR platform. The physician informaticist completed a 9-point checklist of efficiency tips with physician trainees covering schedule organization, chart review, speed buttons, billing, note personalization/optimization, preference lists, quick actions, and quick tips. We collected postsession survey data assessing for net promoter score (NPS) and open-ended feedback. We conducted financial analysis of pre- and post-mini-sprint efficiency levels and financial data.

Results Seventy-six sessions were conducted with 32 primary care physicians, 28 specialty physicians, and 16 nonphysician providers within primary care and other areas. Thirty-seven physicians completed the postsession survey. The average NPS for the completed mini-sprint sessions was 97. The proficiency score had a median of 6.12 (Interquartile range (IQR): 4.71–7.64) before training, and a median of 7.10 (IQR: 6.25–8.49) after training. Financial data analysis indicates that higher level billing codes were used at a greater frequency post-mini-sprint. The revenue increase 12 months post-mini-sprint was $213,234, leading to a return of $75,559.50 for 40 providers, or $1,888.98 per provider in a 12-month period.

Conclusion Our data show that mini-sprint sessions were effective in optimizing efficiency within the EHR platform. Financial analysis demonstrates that this type of training program is sustainable and pays for itself. There was high satisfaction with the mini-sprint training modality, and feedback indicated an interest in further mini-sprint training sessions for physicians and nonphysician staff.
Advanced computational approaches shed light on protein aggregation and disease mechanisms
Authors: Ikenson Ben
Published: April 2024

Examining the molecular basis for protein aggregation
Ultra-sensitive current bistability and light switching in a resonant tunneling superlattice transistor
Authors: Kumar Raman , Kaufman Robert B. , Hsiao Fu-Chen , Leburton Jean-Pierre , Dallesasse John M.
Published: April 2024

Bistability in the current–voltage characteristics of semiconductor superlattices and quantum cascade laser structures has the potential for wide-ranging applications, particularly in sensing systems. However, the interdependency of applied bias and current injection in conventional two-terminal structures has led to complications in analysis and rendered the bistability phenomenon difficult to implement in practical applications. Here, we report a new kind of electronic bistability coupled to optical switching in a resonant tunneling bipolar superlattice transistor. This bistability manifests as sharp discontinuities in the collector current with extremely small variations of the applied voltage, which arise from unstable tunneling transmission across the hetero-barrier between the two-dimensional electron gas (2DEG) at the edge of the transistor base and the collector superlattice structure. The electronic transitions between high and low quantum mechanical transmissions are demonstrated to be caused by self-consistent variations of the internal electric field at the heterointerface between the 2DEG and the superlattice. They are also present in the base current of the three-terminal device and result in sharp switching of near-infrared spontaneous light emission output from an interband radiative recombination process with a peak emission wavelength of 1.58 μm. A comprehensive quantum mechanical theoretical model accounting for the self-consistent bistable tunneling transmission is in quantitative agreement with the experimental data. The measured peak transconductance sensitivity value of 6000 mS can be used in the highly sensitive detector and non-linear device applications.
Radiation transfer in the spectra of short-pulse laser-heated targets
Authors: London Richard A. , Scott Howard A. , Martin Madison E.
Published: April 2024

The conditions in laser-produced plasmas are frequently determined with x-ray spectroscopy by comparing calculated to measured spectra. Line spectra from K-shell transitions of low- to mid-atomic number elements are most often used since the important physical processes are well understood and reliable spectra can be readily measured and calculated. Radiation transfer effects due to large optical depths of strong lines can influence the spectra. In this work, the effects of radiation transfer on the emission spectra of short-laser pulse-heated targets are studied. The possible errors made in inferring electron temperature by not including radiation transfer are quantified. The inclusion of radiative transfer in spectral calculations improves the accuracy of typical temperature diagnostics and allows the use of strong lines for diagnostics.
Cardiac abnormality detection with a tiny diagonal state space model based on sequential liquid neural processing unit
Authors: Huang Zhaojing , Leung Wing Hang , Cui Jiashuo , Yu Leping , Herbozo Contreras Luis Fernando , Truong Nhan Duy , Nikpour Armin , Kavehei Omid
Published: April 2024

This manuscript introduces a novel method for cardiac abnormality detection by combining the Diagonal State Space Sequence (S4D) model with the Closed-form Continuous-time neural network (CfC), yielding a highly effective, robust, generalizable, and compact solution. Our proposed S4D-CfC model is evaluated on 12- and single-lead electrocardiogram data from over 20 000 patients. The system exhibits validation results with strong average F1 score and average area under the receiver operating characteristic curve values of 0.88% and 98%, respectively. To demonstrate the tiny machine learning of our 242 KB size model, we deployed the system on relatively resource-constrained hardware to evaluate its training performance on-the-edge. Such on-device fine-tuning can enhance personalized solutions in this context, allowing the system to learn each patient’s data features. A comparison with a structured 2D convolutional long short-term memory CfC model demonstrates the S4D-CfC model’s superior performance. The proposed model’s size can be significantly reduced to 25 KB, maintaining reasonable performance on 2.5 s data, 75% shorter than the original 10 s data, making it suitable for resource-constrained hardware and minimizing latency. In summary, the S4D-CfC model represents a groundbreaking advancement in cardiac abnormality detection, offering robustness, generalization, and practicality with the potential for efficient deployment on limited-resource platforms, revolutionizing healthcare technology.
AB-G0W0: A practical G0W0 method without frequency integration based on an auxiliary boson expansion
Authors: Tölle Johannes , Kin-Lic Chan Garnet
Published: April 2024

Common G0W0 implementations rely on numerical or analytical frequency integration to determine the G0W0 self-energy, which results in a variety of practical complications. Recently, we have demonstrated an exact connection between the G0W0 approximation and equation-of-motion quantum chemistry approaches [J. Tölle and G. Kin-Lic Chan, J. Chem. Phys. 158, 124123 (2023)]. Based on this connection, we propose a new method to determine G0W0 quasiparticle energies, which completely avoids frequency integration and its associated problems. To achieve this, we make use of an auxiliary boson (AB) expansion. We name the new approach AB-G0W0 and demonstrate its practical applicability in a range of molecular problems.
Photogenerated carrier dynamics of Mn2+ doped CsPbBr3 assembled with TiO2 systems: Effect of Mn doping content
Authors: Du Luchao , An Jie , Katayama Tetsuro , Duan Menghan , Shi XiaoPing , Wang Yunpeng , Furube Akihiro
Published: April 2024

In recent years, all-inorganic perovskite materials have become an ideal choice for new thin film solar cells due to their excellent photophysical properties and have become a research hotspot. Studying the ultrafast dynamics of photo-generated carriers is of great significance for further improving the performance of such devices. In this work, we focus on the transient dynamic process of CsPbBr3/TiO2 composite systems with different Mn2+ doping contents using femtosecond transient absorption spectroscopy technology. We used singular value decomposition and global fitting to analyze the transient absorption spectra and obtained three components, which are classified as hot carrier cooling, charge transfer, and charge recombination processes, respectively. We found that the doping concentration of Mn2+ has an impact on all three processes. We think that the following two factors are responsible: one is the density of defect states and the other is the bandgap width of perovskite. As the concentration of doped Mn2+ increases, the charge transfer time constant shows a trend of initially increasing, followed by a subsequent decrease, reaching a turning point. This indicates that an appropriate amount of Mn2+ doping can effectively improve the photoelectric performance of solar cell systems. We proposed a possible charge transfer mechanism model and further elucidated the microscopic mechanism of the effect of Mn2+ doping on the interface charge transfer process of the CsPbBr3/TiO2 solar cell system.
Investigation on the effect of particle parameters on the erosion and erosion prediction model of the Pelton turbine
Authors: Han Lei , Guo Chuanliang , Gao Yujie , Li Deyou , Wang Hongjie , Liu Yongxin , Iranzo Alfredo , Qin Daqing
Published: April 2024

The Pelton turbine will play a massive role in China's water conservancy and power generation development process. In practical engineering applications, sediment will erode the components of the Pelton turbine when they come into contact, threatening the safe and stable operation of the unit. Therefore, based on the Eulerian–Lagrangian method, this study analyzes the effects of particle size, concentration, and position angle on the degree and distribution of erosion of each component without considering the cavitation effect of the flow. The results show that the larger the particle size, the more concentrated the distribution, and the more severe the abrasion caused on the spray needle and water bucket. However, the degree of nozzle erosion weakens, and the erosion area increases. It was also found that the higher the concentration, the more severe the abrasion caused to each component. When the jet completely hits the position on the bucket, due to the low impact speed, the impact angle remains almost unchanged, resulting in less erosion. Finally, the classic Finnie model was refined by adjusting the average erosion rate, particle size, concentration, and rotation angle. This modification yielded an enhanced model, mainly showcasing improved performance for moderate particle sizes.
Effects of liquid water injection on flame surface topology and propagation characteristics in spray flames: A direct numerical simulation analysis
Authors: Concetti R. , Hasslberger J. , Chakraborty N. , Klein M.
Published: April 2024

The effects of water injection on flame surface topology and local flame propagation characteristics have been analyzed for statistically planar turbulent n-heptane spray flames with an overall (i.e., liquid + gaseous) equivalence ratio of unity using carrier-phase direct numerical simulations. Most fuel droplets have been found to evaporate as they approach the flame even though some droplets can survive until the burnt gas side is reached, whereas water droplets do not significantly evaporate ahead of the flame and the evaporation of water droplets starts to take place in the reaction zone and is completed within the burnt gas. However, the gaseous-phase combustion occurs predominantly in fuel–lean mode although the overall equivalence ratio remains equal to unity. The water injection has been found to suppress the fuel droplet-induced flame wrinkling of the progress variable isosurface under the laminar condition, and this effect is particularly strong for small water droplets. However, turbulence-induced flame wrinkling masks these effects, and thus, water injection does not have any significant impact on flame wrinkling for the turbulent cases considered here. The higher rate of evaporation and the associated high latent heat extraction for smaller water droplets induce stronger cooling effects, which weakens the effects of chemical reaction. This is reflected in the decrease in the mean values of density-weighted displacement speed with decreasing water droplet diameter. The weakening of flame wrinkling as a result of injection of small water droplets is explained through the curvature dependence of the density-weighted displacement speed. The combined influence of cooling induced by the latent heat extraction of water droplets and flame surface flattening leads to a decrease in volume-integrated burning rate with decreasing water droplet diameter in the laminar cases, whereas the cooling effects are primarily responsible for the drop in burning rate with decreasing water droplet diameter in the turbulent cases.
High energy storage density in AgNbO3-based lead-free antiferroelectrics using A/B-site co-doping strategy
Authors: Zhang N. , Jiang J. R. , Zhang J. X. , Wang J. Y. , Jia P. P. , Zhu M. M. , Guo Y. Y. , Zhou S. , Song G. L.
Published: April 2024

Lead-free antiferroelectric AgNbO3 ceramics have garnered extensive attention due to their rapid charge/discharge capabilities and environmentally friendly nature, holding immense potential for energy storage applications. However, the practical utilization of AgNbO3 has been hindered by its low energy storage density. This study employed an A/B-site co-doping strategy, which yielded positive effects on the energy performance of AgNbO3 ceramics. By modifying the A/B-sites with equivalent amounts of Bi3+ and Y3+ ions, enhanced maximum polarization, improved breakdown field, and slimmer hysteresis loops were simultaneously achieved, as the combined effects of refined grain size, wider optical bandgap, and randomly distributed antiferroelectric nanodomains, which were verified through the scanning electron microscope, transmission electron microscope, and ultraviolet–visible spectrum. As a consequence, a high energy storage density of 5.40 J/cm3 accompanied by an energy storage efficiency of 56.5% was achieved in the Ag0.97Bi0.01Nb0.994Y0.01O3 ceramic under a relatively low electric field of 190 kV/cm. This study underscores the effectiveness of A/B-site aliovalent co-doping as a viable strategy for developing high-performance ceramic capacitors for energy storage applications.
Sedimentation of a spheroidal particle in an elastoviscoplastic fluid
Authors: Abbasi Yazdi Alie , D'Avino Gaetano
Published: April 2024

The sedimentation dynamics of a prolate spheroidal particle in an unbounded elastoviscoplastic (EVP) fluid is studied by direct finite element simulations under inertialess flow conditions. The Saramito–Giesekus constitutive equation is employed to model the suspending liquid. The arbitrary Lagrangian–Eulerian formulation is used to handle the particle motion. The sedimentation, lift, and angular velocities of spheroids with aspect ratio between 1 and 8 are computed as the initial orientation, Bingham, and Weissenberg numbers are varied. Similar to the purely viscoelastic case, a spheroid in an EVP fluid rotates up to align its major axis with the applied force. As the Bingham number increases, the settling rate monotonically reduces, while the angular velocity first increases and then decreases. The initial orientation has a relevant effect on the particle stoppage because of the different drag experienced by the spheroid as its orientation is varied. The yielded and unyielded regions around the spheroid reveal that, for particle oriented transversely to the force, the yielded envelope shrinks near the tips due to the fast spatial decay of the stresses, and unyielded regions appear along the surface of the particle, similar to the solid caps observed at the front and back of a sphere. Fluid plasticity enhances the negative wake phenomenon that is observed at Weissenberg numbers significantly lower than the purely viscoelastic case. The results of the drag correction coefficient for particles aligned with longest axis along the force are presented.
Phonon transport simulation with an extended VOF scheme for nano-structured thin film
Authors: Takahara Yoshiya , Matsumoto Mitsuhiro , Hanaoka Misaki , Iwakawa Manabu
Published: April 2024

Control of phonon transport in solid devices is important for thermoelectric energy conversion and phononic crystal technology, and much attention has been paid to sub-micrometer or nanometer scale structures for that purpose. In order to investigate how various nano-structures affect the phonon transport, we have developed a numerical simulation code based on the Boltzmann transport equation of phonon distribution function in the reciprocal space. To appropriately treat the phonon transport at interface of an arbitrary shape, we newly introduced a volume of fluid like scheme, which was originally developed for multi-phase flow simulation. As a test of the developed simulation code, we investigated two-dimensional thin silicon films with two types of hole shape and two types of hole arrangement. The results essentially agree with recent experiments.
Multimodal learning of heat capacity based on transformers and crystallography pretraining
Authors: Huang Hongshuo , Barati Farimani Amir
Published: April 2024

Thermal properties of materials are essential to many applications of thermal electronic devices. Density functional theory (DFT) has shown capability in obtaining an accurate calculation. However, the expensive computational cost limits the application of the DFT method for high-throughput screening of materials. Recently, machine learning models, especially graph neural networks (GNNs), have demonstrated high accuracy in many material properties’ prediction, such as bandgap and formation energy, but fail to accurately predict heat capacity(CV) due to the limitation in capturing crystallographic features. In our study, we have implemented the material informatics transformer (MatInFormer) framework, which has been pretrained on lattice reconstruction tasks. This approach has shown proficiency in capturing essential crystallographic features. By concatenating these features with human-designed descriptors, we achieved a mean absolute error of 4.893 and 4.505 J/(mol K) in our predictions. Our findings underscore the efficacy of the MatInFormer framework in leveraging crystallography, augmented with additional information processing capabilities.
Finite temperature dynamics in a polarized sub-Ohmic heat bath: A hierarchical equations of motion-tensor train study
Authors: Takahashi Hideaki , Borrelli Raffaele , Gelin Maxim F. , Chen Lipeng
Published: April 2024

The dynamics of the sub-Ohmic spin-boson model under polarized initial conditions at finite temperatures is investigated by employing both analytical tools and the numerically accurate hierarchical equations of motion-tensor train method. By analyzing the features of nonequilibrium dynamics, we discovered a bifurcation phenomenon, which separates two regimes of the dynamics. It is found that before the bifurcation time, increasing temperature slows down the population dynamics, while the opposite effect occurs after the bifurcation time. The dynamics is highly sensitive to both initial preparation of the bath and thermal effects.
High-speed photography and particle image velocimetry of cavitation in a Venturi tube
Authors: Wang Zhen , Zhao Qin , Yang Zeyuan , Liang Ruifeng , Li Zhenggui
Published: April 2024

This article details the construction of an experimental visualization platform for observing cavitation. The platform uses high-speed photography and particle image velocimetry (PIV) techniques to conduct experimental research into the flow pattern and vortex field of cavitation in Venturi tubes. Dynamic mode decomposition is employed to extract the energy distribution characteristics of the cavitation flow field. Cavitation occurs at an exit-to-inlet pressure ratio of 0.595, and the length of the cavitation zone increases as this ratio decreases. When the pressure ratio reaches 0.280, the flow rate remains almost constant and the flow becomes chocked. The cavitation shape evolves periodically in the chocking flow, and the cavitation zone can be divided into three parts: an initiation and development area, a fusion area, and a collapse area. The fusion area exhibits periodic changes in the form of contraction, expansion, and re-contraction. Near the wall, the collapse area exhibits complex boundary conditions, with re-entrant jet causing bubble aggregation, rolling, and shedding. PIV and energy extraction reveal that vortices primarily appear near the wall, where they undergo a periodic process of fragmentation and fusion. The strength of the vortices exhibits a small–large–small pattern that is related to the cloud aggregation, rolling, and shedding caused by the re-entrant jet.
Aeroacoustic investigation of a ducted wind turbine employing bio-inspired airfoil profiles
Authors: Mozafari Mostafa , Sadeghimalekabadi Mahyar , Fardi Amirhossein , Bruecker Christoph , Masdari Mehran
Published: April 2024

Ducted wind turbines for residential purposes are characterized by a lower diameter with respect to conventional wind turbines for on-shore applications. The noise generated by the rotor plays a significant role in the overall aerodynamic noise. By making modifications to the blade sections of the wind turbine, we can alter the contributions of aeroacoustic noise sources. This study introduces innovative wind turbine blade designs inspired by owl wing characteristics, achieving significant noise reduction without compromising aerodynamic performance. A three-dimensional scan of an owl wing was first employed to derive a family of airfoils. The airfoils were employed to modify the blade of a referenced wind turbine airfoil section at various positions on the blade span to determine a blade operating more efficiently at the tip-speed ratio of the original one. While maintaining the same aerodynamic performance, the bio-inspired profiles show a more uniform pressure coefficient distribution, considerably decreasing in the noise level. Furthermore, this study makes considerable progress in ducted wind turbine design by obtaining an 8 dB noise reduction and a 12% improvement in sound pressure level. An in-depth aerodynamic examination shows a 6.4% rise in thrust force coefficient and optimized power coefficients, reaching a peak at a tip speed ratio of 8, demonstrating improved energy conversion efficiency. The results highlight the dual advantage of the innovative design: significant noise reduction and enhanced aerodynamic efficiency, offering a promising alternative for urban wind generation.
Fluid dynamics of a flapping wing interacting with the boundary layer at a flat wall
Authors: Lin Chihao , Jia Pan , Wang Chao , Zhong Zheng
Published: April 2024

In this paper, we consider the fluid dynamics of a flapping wing interacting with a boundary layer developed at a no-slip flat wall. Direct numerical simulations are carried out via implementing the non-iterative immersed boundary-lattice Boltzmann method, over a Reynolds number range of 10≤Re≤1000, for a fixed Strouhal number of St = 0.3 and for a given symmetric plunging and pitching flapping motion. The interactions between the wing and the boundary layer are modulated by varying the mean distance of the wing to the wall H0. The results indicate that the presence of the boundary layer at the wall amplifies the fluctuations in both lift and drag due to the boundary layer separation, in contrast to the pure ground effect. This separation also leads to the decrease in both average lift and average drag over one flapping cycle when H0 is low. When it comes to the flow patterns in the wake, it generally gets more complex for a low H0 and/or a high Re. Secondary vortices can be observed for Re≥500 in the present configuration, which either evolve by themselves or interact with the vortices in the wake while being convected downstream and dissipated via viscosity. In the end, a dynamic mode decomposition analysis is performed to explore further the flow structures in the wake. One observes the sheltering effect of the boundary layer that the vortices in the wake are prevented from penetrating the boundary layer, while this effect will not hold if the vortex intensity is sufficiently high, such as the low order mode of the case for Re≥1000 in this study.
Interfacial water on collagen nanoribbons by 3D AFM
Authors: Arvelo Diana M. , Garcia-Sacristan Clara , Chacón Enrique , Tarazona Pedro , Garcia Ricardo
Published: April 2024

Collagen is the most abundant structural protein in mammals. Type I collagen in its fibril form has a characteristic pattern structure that alternates two regions called gap and overlap. The structure and properties of collagens are highly dependent on the water and mineral content of the environment. Here, we apply 3D AFM to characterize at angstrom-scale resolution the interfacial water structure of collagen nanoribbons. For a neutral tip, the interfacial water structure is characterized by the oscillation of the water particle density distribution with a value of 0.3 nm (hydration layers). The interfacial structure does not depend on the collagen region. For a negatively charged tip, the interfacial structure might depend on the collagen region. Hydration layers are observed in overlap regions, while in gap regions, the interfacial solvent structure is dominated by electrostatic interactions. These interactions generate interlayer distances of 0.2 nm.
Three-dimensional particle image velocimetry measurement through three-dimensional U-Net neural network
Authors: Cao Lixia , Hossain Md. Moinul , Li Jian , Xu Chuanlong
Published: April 2024

This paper proposes a light field (LF) three-dimensional (3D) particle image velocimetry (PIV) method based on a digital refocused algorithm and 3D U-Net neural network for 3D three-component (3D-3C) velocity measurement. A digital refocused algorithm is used to generate a stack of LF-refocused images of tracer particles for establishing the 3D U-Net. The 3D U-Net is then used for the 3D particle field reconstruction. Based on a pair of 3D particle fields, the 3D-3C velocity field is obtained through a 3D cross correlation algorithm. Numerical simulations and experiments are conducted to analyze the accuracy and efficiency of the proposed method. The simulation results show that the elongation along the depth direction and the efficiency of the 3D particle field reconstruction are improved by the 3D U-Net. The 3D U-Net also provides a better correlation coefficient. The experimental results show that the reconstruction time of the proposed method is ∼220 s which is 10 times faster than the LF tomographic PIV. This further demonstrates that the proposed method improves the reconstruction efficiency without affecting the accuracy of velocity measurement.
Numerical simulation of the interaction between a planar shock wave and a backward-facing triangular bubble containing gases with different Atwood numbers
Authors: Thangadurai Murugan , Kundu Abhishek , Biswas Gautam
Published: April 2024

The interaction between a shock wave and an interface delineating two gases engenders intricate flow physics, with particular attention drawn to the hydrodynamic instability due to its practical significance. Previous studies have primarily focused on elucidating different wave patterns and instabilities evolution at the interface during the initial phase of shock interaction with cylindrical or spherical bubbles. However, scant literature has shifted its focus toward exploring the long-term morphology of bubbles, especially those characterized by polygonal interfaces. Notably, the detailed examination of shock interaction with a polygonal interface, such as a triangular one with a constant incident angle, remains largely unexplored in existing literature. Recently, the longtime evolution of detailed flow structures across the interface of shock-forward-facing triangular bubbles was captured by Kundu et al. [“A study on dynamics of shock-accelerated forward-facing triangular bubbles at different Atwood numbers,” Phys. Fluids 36, 016110 (2024)] through numerical simulation. In this study, the dynamics of a shock-accelerated backward-facing triangular interface containing various gases, namely, Sulfur Hexafluoride, Refrigerant-22, Argon, Neon, and Helium, is studied for a shock Mach number of 1.21. Simulations were performed by solving the two-dimensional Euler equation using low-dissipative advection upwind splitting methods (AUSMD), in conjunction with a derived ninth-order upwind scheme and a four-stage third-order Runge–Kutta scheme for temporal integration. The development of Richtmyer–Meshkov (RM) and Kelvin–Helmholtz (K–H) instabilities at the interface, mixing, and normalized movements of backward-facing triangular bubbles is captured at different Atwood (At) numbers.
Numerical study of free stream turbulence effects on dynamic stall of pitching tubercled wings
Authors: Zhao Ming , Chen Weibin , Chen Jiahuan , Xu Lianchao , Li Xiaojian , Liu Zhengxian
Published: April 2024

The feasibility of a tubercled leading-edge in dynamic stall control has been validated, and the impacts of an upstream cylinder wake have already been discussed in the previous research. However, the influences of wake coherent characteristics on the dynamic stall process are inevitable. To this end, the synthetic turbulence method was adopted in the present study to generate incoming turbulence. The suppression of dynamic stall could be observed according to the shrink of hysteresis loop of aerodynamic lift. Then, the dynamic stall mechanisms have been analyzed with the help of mode decomposition method. The emergence and development of the leading-edge vortex indicate the increase in aerodynamic lift, while he detachment of dynamic stall vortex leads to the lift degradation during the onset of dynamic stall. Eventually, the influence of turbulence intensity (TI) has also been discussed through the comparison of TI = 5% and TI = 10% cases. It turns out that flow separation is more remarkable at both peak and trough sections in the case of TI = 5%, which is intrinsically caused by the suppression of resistance of adverse pressure gradient.
Fighting fire and fumes: risk awareness and protective practices among Western Australian firefighters
Authors: Padamsey Kiam , Wallace Ruth , Liebenberg Adelle , Cross Martyn , Oosthuizen Jacques
Published: April 2024

Background In Western Australia, the issue of bushfires (wildfires) poses a persistent health risk to both volunteer and career forestry firefighters, populations that have been historically understudied. Aims This descriptive qualitative study aimed to examine firefighters’ level of understanding concerning hazardous exposures, their Personal Protective Equipment (PPE) protocols and their decontamination practices. Methods Guided by the socioecological model, 23 semi-structured interviews were conducted with firefighters representing both volunteer and forestry sectors. Key results Results indicate a gap in knowledge regarding the health risks associated with bushfire-generated smoke and contaminants among volunteer firefighters. Forestry firefighters, conversely, showed a greater awareness of these risks. Social dynamics, such as peer pressure, were identified as historical deterrents to PPE use, although recent trends indicate positive change. Forestry firefighters also highlighted systemic shortcomings, including inadequate provision of respiratory protection and lack of decontamination facilities for cleaning themselves and their PPE. Conclusion This study underscores the critical need for educational initiatives to address these gaps in understanding, along with organisational reforms to promote a culture encouraging PPE use and to provide essential resources for effective decontamination. Implications This research emphasises that a multi-level approach is essential for safeguarding the health of firefighters in bushfire-prone environments.
Evolution of homologous recombination rates across bacteria
Authors: Torrance Ellis L. , Burton Corey , Diop Awa , Bobay Louis-Marie
Published: April 2024

Bacteria are nonsexual organisms but are capable of exchanging DNA at diverse degrees through homologous recombination. Intriguingly, the rates of recombination vary immensely across lineages where some species have been described as purely clonal and others as “quasi-sexual.” However, estimating recombination rates has proven a difficult endeavor and estimates often vary substantially across studies. It is unclear whether these variations reflect natural variations across populations or are due to differences in methodologies. Consequently, the impact of recombination on bacterial evolution has not been extensively evaluated and the evolution of recombination rate—as a trait—remains to be accurately described. Here, we developed an approach based on Approximate Bayesian Computation that integrates multiple signals of recombination to estimate recombination rates. We inferred the rate of recombination of 162 bacterial species and one archaeon and tested the robustness of our approach. Our results confirm that recombination rates vary drastically across bacteria; however, we found that recombination rate—as a trait—is conserved in several lineages but evolves rapidly in others. Although some traits are thought to be associated with recombination rate (e.g., GC-content), we found no clear association between genomic or phenotypic traits and recombination rate. Overall, our results provide an overview of recombination rate, its evolution, and its impact on bacterial evolution.