bluuebunny/crossref_metadata_2025 huggingface dataset:
Extensive Sequestration Chronic Maxillary Osteomyelitis in an Uncontrolled Diabetic Patient: Comprehensive Case Management of a Rare Entity
Authors: El Fadhlallah Prasiddha Mahardhika , Nugraha Andreas Pratama , Prasetio Okky , Mulyawan Indra
Published: October 2023

The hallmark of osteomyelitis was progressive bone destruction and sequestrum formation. In the underlying disease, like diabetes mellitus, osteomyelitis becomes severe and exacerbates the condition. It was essential for the oral and maxillofacial surgeon to comprehend its complex medical and surgical management to achieve complete disease eradication. The aim of this article was to report a rare case and comprehensive management of extensive sequestrating maxillary osteomyelitis with uncontrolled diabetes mellitus patients. A 58-year-old male patient with pain and swelling accompanied by discharge of pus in the sinistra maxilla region. The systemic disease was identified as uncontrolled diabetes mellitus, and had a history of unhealing wounds 1 year ago after upper left molar extraction. Computed tomography scan result showed extensive sequester formation and bony destruction in the right extending to the left maxilla. Microbial culture results were Klebsiella pneumoniae and Morganella morganii. Subsequently, extensive sequestrectomy and multiple extractions of the involved jaw and teeth were performed after diabetes mellitus was regulated. A suspension suture against oral and nasal mucosa was performed to avoid dead space formation. Comprehensive perioperative management in maxillary osteomyelitis in uncontrolled diabetes mellitus includes sequestrectomy, definitive antibiotic therapy based on culture results, and diabetes regulation to improve the successful management of this case.
Ultrasonographic Evaluation of Nontraumatic Gastrointestinal Emergencies in Children
Authors: Hosale Prerana , Solanki R.S. , Puri Archana , Agarwal Shilpi , Abbey Pooja
Published: October 2023

Acute, nontraumatic gastrointestinal pathologies are commonly encountered in the pediatric emergency department. They often pose a diagnostic dilemma with an assemblage of various etiologies, depending on the age and clinical features. Despite the advent of computed tomography, various issues pertinent to children make ultrasonography (USG) the initial imaging modality of choice in investigating acute gastrointestinal pathologies. This article discusses the ultrasonographic approach to acute gastrointestinal pathologies in children, and how sonography is instrumental in guiding diagnosis and treatment. Characteristic USG findings of common pediatric gastrointestinal emergencies—including acute appendicitis, intussusception, Meckel's diverticulitis, midgut volvulus, bowel perforation, and abdominal tuberculosis—are illustrated in this pictorial review.
Ultrasound Imaging of Thyroid Pathologies: A Pictorial Review
Authors: Mohan Supraja Laguduva , Govindarajalou Ramkumar , Chakkalakkoombil Sunitha Vellathussery , Ramachandran Madhan , Venkatesh Karthik
Published: October 2023

With its complex embryological origin, the thyroid can be affected by various congenital, developmental, benign, and malignant pathologies. Ultrasound, which is free from radiation and offers good spatial resolution, is the initial modality of choice in congenital hypothyroidism and is used in conjunction with scintigraphy. High-resolution ultrasound also aids in early diagnosis, risk stratification, and follow-up of nodules. While fine-needle aspiration cytology is the preferred method for further evaluation of thyroid nodules, ultrasound guidance reduces the likelihood of obtaining nondiagnostic samples. Numerous risk stratification guidelines for thyroid nodules have been developed by various societies over the past decade, with the most popular being the American College of Radiology—Thyroid Imaging Reporting and Data System. A comprehensive understanding of the varying morphological appearances of thyroid nodules and the consistent use of risk stratification guidelines can accurately detect incidental malignancies while avoiding unnecessary intervention in seemingly benign nodules.
Imaging of Pulmonary Manifestations in Chronic Kidney Disease: A Review
Authors: Das Abanti , Naranje Priyanka , Bhalla Ashu Seith , Das Chandan J.
Published: October 2023

Lungs and kidneys share a symbiotic relationship in maintaining homeostasis of body. Hence, derangement of one system is bound to affect the functioning of the other. The thoracic manifestations of chronic renal failure present a wide spectrum ranging from problems related to fluid and salt balance, calcium–phosphate metabolism, compromised immunity, and additional issues related to different modes of dialysis. In most of the cases, chest radiograph coupled with ultrasound and computed tomography (CT) are sufficient to offer a definitive diagnosis. This review aims to summarize the imaging features of thoracic manifestations of chronic kidney disease (CKD) with emphasis on imaging-based discriminating features.
A Retrospective Study of the Association between Respiratory Tract Viral PCR Panel Results and Clinical Outcomes in Children with Cancer and Febrile Neutropenia and Review of the Literature
Authors: Terzi Özlem , Karabulut Nuran , Uysalol Ezgi Paslı , Kaçar Ayşe Gonca , Solgun Hüseyin Avni , Ertürk Saide , Şimşek Halil İbrahim , Bayram Cengiz , Ayçiçek Ali
Published: October 2023

Objective The role of respiratory viral pathogens (RVPs) in children with cancer having febrile neutropenic (FEN) episodes has not been well studied. The objectives of this study were to investigate the prevalence and clinical outcomes of RVP in this group.

Methods Pediatric patients with cancer and an episode of FEN, presenting between March 2021 and March 2022 were included. All data were retrospectively retrieved from patient files. A throat swab sample was obtained for the detection of 17 RVPs and evaluated by a polymerase chain reaction (PCR) method.

Results A total of 110 (male n = 76; 69.1%) patients with a mean ± standard deviation age of 6.68 ± 4.92 years were included. Reproduction in PCR was seen in 76 (69.1%) children. Rhinovirus (31.6%) and respiratory syncytial virus (15.8%) were the most frequently detected viruses. Mixed respiratory viruses (coinfections of ≥2 viruses) were only seen in 13%. The median (range) duration of hospitalization was 11 (2–143) days, and 8.2% of the children were admitted to the pediatric intensive care unit (PICU). The median (range) length of stay (LOS) in the PICU was 8 (1–100) days. Overall mortality rate was 3.6%. There was no significant difference in LOS in the hospital, rate of admission to PICU, LOS in the PICU, and the mortality rate between children with and without growth in PCR (p > 0.05).

Conclusion There was high prevalence of RVP in children with cancer and FEN. However, given that having a positive RVP does not affect LOS in the hospital/PICU or disease severity, in this population, there was no association between positive PCR findings and clinical features investigated or outcome.
“Lid Switch Flap” for Subtotal Upper Eyelid Reconstruction: Where the Flap Pedicle and the Point of Rotation Should be Located
Authors: Karonidis Athanasios , Tsallas Stefanos , Louros Liberis
Published: October 2023

We report our experience using the “lid switch flap” for the reconstruction of large upper eyelid defects, emphasizing on the design, the point of flap rotation, and the detailed description of the surgical technique. From 2018 to 2021, three patients with squamous cell carcinoma (SCC) invading 50 to 70% of the upper eyelid underwent tumor excision. The defects were reconstructed using the two-stage “lid switch flap” method. At the first stage, the “switch flap” from the lower eyelid was designed medially based preferably, elevated and “switched” to the defect, whereas the pedicle was divided at the second stage in 2 to 3 weeks. The mean of defect widths after tumor excision (D) was 23.6 mm (range: 18–29 mm) and the mean of widths of lid switch flaps (F) was 15.3 mm (range: 10–20 mm), and thus, the mean of F/D ratio was 0.63 (range: 0.55–0.69). The histopathology report confirmed the complete excision of the SCCs. The patients were followed up for 2 years. The functional and aesthetic results were excellent.

Level of Evidence Level II, therapeutic study.
A New Method of Matrix-Based Triage for Nuclear Disasters
Authors: Kumar Pramod , Gupta Apoorva
Published: October 2023

During nuclear disaster, infrastructure is severely damaged and injuries are often combined with trauma/burns and whole-body radiation. This makes triage difficult, especially when resources are severely deficient. To solve this problem, in this article, the authors have suggested a new less technology-dependent radiation dosimetry and quick triage using a specially designed triage matrix during nuclear disasters.
Prognostic Relevance of the Lung Ultrasound Score: A Multioutcome Study in Infants with Respiratory Distress Syndrome
Authors: Szymański Piotr , Puskarz-Gąsowska Joanna , Hożejowski Roman , Stefańska Małgorzata , Błaż Witold , Sadowska-Krawczenko Iwona , Majewska Urszula , Tomaszkiewicz Anna , Piotrowska Małgorzata , Kusibab-Mytych Marta , Słowik-Wasyluk Natalia , Kruczek Piotr , Bokiniec Renata
Published: October 2023

Objective There is growing evidence for the usefulness of the lung ultrasound score (LUS) in neonatal intensive care. We evaluated whether the LUS is predictive of outcomes in infants with respiratory distress syndrome (RDS).

Study Design Neonates less than 34 weeks of gestational age were eligible for this prospective, multicenter cohort study. The outcomes of interest were the need for mechanical ventilation (MV) at <72 hours of life, the need for surfactant (SF), successful weaning from continuous positive airway pressure (CPAP), extubation readiness, and bronchopulmonary dysplasia. Lung scans were taken at 0 to 6 hours of life (Day 1), on Days 2, 3, and 7, and before CPAP withdrawal or extubation. Sonograms were scored (range 0–16) by a blinded expert sonographer. The area under the receiver operating characteristic curve (AUC) was used to estimate the prediction accuracy of the LUS.

Results A total of 647 scans were obtained from 155 newborns with a median gestational age of 32 weeks. On Day 1, a cutoff LUS of 6 had a sensitivity (Se) of 88% and a specificity (Sp) of 79% to predict the need for SF (AUC = 0.86), while a cutoff LUS of 7 predicted the need for MV at <72 hours of life (Se = 89%, Sp = 65%, AUC = 0.80). LUS acquired prior to weaning off CPAP was an excellent predictor of successful CPAP withdrawal, with a cutoff level of 1 (Se = 67%, Sp = 100%, AUC = 0.86).

Conclusion The LUS has significant predictive ability for important outcomes in neonatal RDS.

Key Points
Prevalence and Risk Factors for Tube-Feeding at Discharge in Infants following Early Congenital Heart Disease Surgery: A Single-Center Cohort Study
Authors: Viswanathan Sreekanth , F. Ong Kaitlyn Jade , Kakavand Bahram
Published: October 2023

Objective Oral feeding difficulty is common in infants after congenital heart disease (CHD) surgical repair and is associated with prolonged hospital stay and increased risk for tube-feeding at discharge (TF). The current understanding of the enteropathogenesis of oral feeding difficulty in infants requiring CHD surgery is limited. To determine the prevalence and risk factors for TF following CHD surgery in early infancy.

Study Design This was a 6-year single-center retrospective cohort study (2016–2021) of infants under 6 months who had CHD surgery. Infants required TF were compared with infants who reached independent oral feeding (IOF).

Results Of the final sample of 128 infants, 24 (18.8%) infants required TF at discharge. The risk factors for TF in univariate analysis include low birth weight, low 5-minute Apgar score, admitted at birth, risk adjustment in congenital heart surgery categories IV to VI, presence of genetic diagnosis, use of Prostin, higher pre- and postsurgery respiratory support, lower weight at surgery, lower presurgery oral feeding, higher presurgery milk calory, delayed postsurgery enteral and oral feeding, higher pre- and postsurgery gastroesophageal reflux disease (GERD), need for swallow study, abnormal brain magnetic resonance imaging (p < 0.05). In the multivariate analysis, only admitted at birth, higher presurgery milk calories, and GERD were significant risk factors for TF. TF had significantly longer hospital stay (72 vs. 17 days) and lower weight gain at discharge (z-score: −3.59 vs. −1.94) compared with IOF (p < 0.05).

Conclusion The prevalence of TF at discharge in our study is comparable to previous studies. Infants with CHD admitted at birth, received higher presurgery milk calories, and clinical GERD are significant risk factors for TF. Mitigating the effects of identified risk factors for TF will have significant impact on the quality of life for these infants and their families and may reduce health care cost.

Key Points
Drug-Induced Hypoglycemia in Neonates Born to Nondiabetic Women Treated with Medications during the Pregnancy or the Labor: A Systematic Review of the Literature
Authors: Maines Evelina , Cardellini Maria Chiara , Stringari Giovanna , Leonardi Letizia , Piccoli Giovanni , Urru Silvana Anna Maria , Maiorana Arianna , Soffiati Massimo , Franceschi Roberto
Published: October 2023

The prompt identification of at-risk newborns for drug-induced hypoglycemia can minimize the risk for adverse side effects, inappropriate investigations, and considerable unnecessary costs. Existing literature discusses drug-induced hypoglycemia, but a systematic description of neonatal hypoglycemia induced or exacerbated by maternal medications is missing. We reviewed the association between neonatal hypoglycemia and maternal medications. We systematically searched the literature according to the PICOS model on drug-induced hypoglycemia in neonates born to nondiabetic women treated with medications during the pregnancy or the labor. The main outcomes of the review were: (1) prevalence of hypoglycemia, (2) risk factors and potential confounders, (3) time at onset and severity of hypoglycemia, (4) dose–response gradient, (5) metabolic features of hypoglycemia, (6) modalities to treat hypoglycemia, and (7) quality of the studies. We included 69 studies in this review and we identified 11 groups of maternal drugs related to neonatal hypoglycemia. Results were classified for each outcome. Our review aims at supporting clinicians in the identification of the newborn at risk for hypoglycemia and in the differential diagnosis of neonatal hypoglycemia. Further studies are necessary to assess the risk of neonatal hypoglycemia associated with common maternal medications.

Key Points
Difficulties in Pregnancy Adjustment as Predictors of Perinatal Depression: Indirect Effects through the Role of Brooding Rumination and Maternal–Fetal Bonding
Authors: Vega-Sanz Maria , Rey-Sáez Ricardo , Berástegui Ana , Sánchez-López Álvaro
Published: October 2023

Objective The aim of this research was to study the ways in which problems of adaptation to pregnancy influence the development of symptoms of perinatal depression via the presence of brooding and low maternal-fetal bonding, in addition to other risk factors previously established in the literature.

Study Design Representative sample of pregnant women in the third trimester of gestation (N = 594) completed an online survey that included sociodemographic data and measures of perinatal depression, adjustment to pregnancy, bonding, and brooding. Other risk factors were also assessed as covariates, such as previous history of depression, generalized anxiety, perceived social support, and experience of stressful life events. Descriptive and correlational analyses were performed on the scores obtained by the subjects with the different instruments. A path model was formulated to establish the pathways through which adjustment influences perinatal depression symptomatology. On the one hand, the presence of brooding (worst adjustment to pregnancy → high brooding → perinatal depression symptomatology), and on the other hand, the quality of maternal-fetal bonding (worst adjustment to pregnancy → poor quality fetal-maternal bonding → perinatal depression symptomatology) would act as a mediator.

Results The factors proposed by the literature were predictive of perinatal depressive symptomatology and the quality of adjustment to pregnancy. Problems adjusting to changes during pregnancy and experiencing it unsatisfactorily may predict individual differences in perinatal depressive symptoms. Significantly, this relationship was mediated by two key factors, the presence of brooding and low quality of the maternal-fetal bond.

Conclusion Our results provide evidence in favor of the existence of multiple paths through which difficulties in adapting to pregnancy can favor the occurrence of higher levels of perinatal depressive symptoms and identify new avenues for developing research in this area and preventive interventions empirically informed.
Platelet Function and Maturity and Related microRNA Expression in Whole Blood in Patients with ST-Segment Elevation Myocardial Infarction
Authors: Pedersen Oliver Buchhave , Hvas Anne-Mette , Pasalic Leonardo , Kristensen Steen Dalby , Grove Erik Lerkevang , Nissen Peter H.
Published: October 2023

Background Reduced effect of antiplatelet therapy has been reported in patients with ST-segment elevation myocardial infarction (STEMI). MicroRNAs (miRs) may influence platelet function and maturity, and subsequently the effect of antiplatelet therapy.

Objectives We aimed to explore the association between miR expression and platelet function and maturity in patients with acute STEMI and healthy individuals.

Methods We performed an observational study of STEMI patients admitted directly to primary percutaneous coronary intervention. Patients were treated with antiplatelet therapy according to guidelines. Within 24 hours after admission, blood samples were obtained to measure: the expression of 10 candidate miRs, platelet function markers using advanced flow cytometry, platelet aggregation, serum thromboxane B2, and platelet maturity markers. Furthermore, blood samples from healthy individuals were obtained to determine the normal variation.

Results In total, 61 STEMI patients and 50 healthy individuals were included. STEMI patients had higher expression of miR-21–5p, miR-26b-5p, and miR-223–3p and lower expression of miR-150–5p, miR423–5p, and miR-1180–3p than healthy individuals. In STEMI patients, the expression of miR-26b-5p showed the most consistent association with platelet function (all p-values <0.05, Spearman's rho ranging from 0.27 to 0.41), while the expression of miR-150–5p and miR-223–3p showed negative associations with platelet function. No association between miR expression and platelet maturity markers was observed.

Conclusion In patients with STEMI, the expression of six miRs was significantly different from healthy individuals. The expression of miR-26b-5p may affect platelet function in acute STEMI patients and potentially influence the effect of antiplatelet therapy.
Exploring the intensity, distribution and evolution of teleconnections using climate network analysis
Authors: Wang Shang , Meng Jun , Fan Jingfang
Published: October 2023

Teleconnections refer to long-range climate system linkages occurring over typically thousands of kilometers. Generally speaking, most teleconnections are attributed to the transmission of energy and propagation of waves although the physical complexity and characteristics behind these waves are not fully understood. To address this knowledge gap, we develop a climate network-based approach to reveal their directions and distribution patterns, evaluate the intensity of teleconnections, and identify sensitive regions using global daily surface air temperature data. Our results reveal a stable average intensity distribution pattern for teleconnections across a substantial spatiotemporal scale from 1948 to 2021, with the extent and intensity of teleconnection impacts increasing more prominently in the Southern Hemisphere over the past 37 years. Furthermore, we pinpoint climate-sensitive regions, such as southeastern Australia, which are likely to face increasing impacts due to global warming. Our proposed method offers new insights into the dynamics of global climate patterns and can inform strategies to address climate change and extreme events.
Enhancement of stimulated Brillouin scattering in multiple resonance regions by two-color light in inhomogeneous flowing plasmas
Authors: Huang Z. M. , Wang Qing , Cheng R. J. , Li X. X. , Lv S. Y. , Liu D. J. , Li X. M. , Zhang S. T. , Chen Z. J. , Wang Qiang , Liu Z. J. , Cao L. H. , Zheng C. Y.
Published: October 2023

The effects of two-color light on stimulated Brillouin scattering (SBS) in an inhomogeneous flowing plasma have been investigated. The three-wave match of SBS is satisfied at multiple spatial locations and the multiple resonance regions occur when the two-color laser incident on an inhomogeneous flowing plasma, leading to multiple scattering of scattered light, which results in an enhancement of the reflectivity of the laser rather than a significant decrease. If the distance between the resonance points is smaller than the resonance length of SBS, the ion acoustic waves generated at different locations are coupled to each other, which enhances SBS. A model of multiple regions resonance of SBS is presented, and a one-dimensional Vlasov–Maxwell code is employed to verify the enhancement.
A fresh look at the vibrational and thermodynamic properties of liquids within the soft potential model
Authors: Xu Haichen , Baggioli Matteo , Keyes Tom
Published: October 2023

Contrary to the case of solids and gases, where Debye theory and kinetic theory offer a good description for most of the physical properties, a complete theoretical understanding of the vibrational and thermodynamic properties of liquids is still missing. Liquids exhibit a vibrational density of states (VDOS) which does not obey Debye law, and a heat capacity which decreases monotonically with temperature, rather than growing as in solids. Despite many attempts, a simple, complete and widely accepted theoretical framework able to formally derive the aforementioned properties has not been found yet. Here, we revisit one of the theoretical proposals, and in particular we re-analyze the properties of liquids within the soft-potential model, originally formulated for glasses. We confirm that, at least at a qualitative level, many characteristic properties of liquids can be rationalized within this model. We discuss the validity of several phenomenological expressions proposed in the literature for the density of unstable modes, and in particular for its temperature and frequency dependence. We discuss the role of negative curvature regions and unstable modes as fundamental ingredients to have a linear in frequency VDOS. Finally, we compute the heat capacity within the soft potential model for liquids and we show that it decreases with temperature, in agreement with experimental and simulation data.
Thickness effect of thin-film barrier layers for enhanced long-term operation of solid oxide fuel cells
Authors: Bernadet L. , Buzi F. , Baiutti F. , Segura-Ruiz J. , Dolado J. , Montinaro D. , Torrell M. , Morata A. , Tarancón A.
Published: October 2023

Highly efficient solid oxide cells are one of the most promising technologies for a sustainable future based on renewable hydrogen. The diffusion barrier layer employed between zirconia-based electrolytes and state-of-the-art oxygen electrodes aims to limit the formation of electrically insulating secondary phases that dramatically reduce the cells’ performance. Conventional barrier layers manufactured by screen-printing technology lead to porous microstructures that enable the formation of insulating SrZrO3, partially blocking the active area of the cells. Opposite, homogeneous and dense barrier layers have proven to be the ultimate solution to limit interdiffusion, substantially improving the cells’ performance. Despite the relevance of this solution, the impact of the barrier layer thickness on the final performance of the cells is still unknown. In this work, gadolinia-doped ceria barrier layers with thicknesses between 200 and 800 nm made by pulsed laser deposition were studied in button cells. Excellent electrochemical performance was obtained for all the cells, improving 45% of the power output of the reference counterparts. Moreover, durability tests performed on the cell with the thinnest layer (200 nm) did not show any measurable degradation for 3500 h of continuous operation under high current densities of 0.77 A cm−2 (∼0.87 V) at 750 °C. Post-mortem characterization by synchrotron nano-x-ray fluorescence of a pristine cell and the aged cell allowed us to observe that some spots of SrZrO3 were present at the cathode/electrolyte interface since the cell manufacturing step without increasing during long-term operation. Indeed, the discontinuity of this insulating phase seems not to be critical for cell operation.
Helicity and dissipation correlation in anisotropic turbulent flow fields
Authors: Pham Oanh L. , Papavassiliou Dimitrios V.
Published: October 2023

The relation between the helicity and the rate of dissipation of turbulent kinetic energy in turbulent flows has been a matter of debate. Herein, direct numerical simulations of turbulent Poiseuille and Couette flow were used in combination with the tracking of helicity, helicity density, and dissipation along the trajectories of passive scalar markers to probe the correlation between helicity and dissipation in anisotropic turbulence. The Schmidt number of the scalar markers varied between 0.7, 6, and infinite (i.e., fluid particles), while the friction Reynolds number for both simulations was 300. The probing tools were the autocorrelation coefficients, the cross correlation coefficients between helicity and dissipation, and the joint probability density function calculated in the Lagrangian framework along the positions of the scalar markers. These markers were released at different locations within the flow field, including the viscous wall sublayer, the transition layer, the logarithmic region, and the outer flow. In addition, conditional statistics for scalar markers that dispersed most or least in the flow field were also calculated. It was found that helicity and dissipation changed along the trajectories of scalar markers; however, helicity and dissipation were not correlated in the Lagrangian framework. There was anticorrelation between helicity and dissipation in the near wall region, which was less obvious in the logarithmic region. More importantly, helicity could be used to characterize the alignment of the fluctuating velocity and vorticity vectors along the trajectories of scalar markers that disperse the farthest in the direction normal to the channel wall.
High-throughput interface prediction and generation scheme: The case of
β
-Ga2O3/AlN interfaces
Authors: Yu Wei , Gui Qingzhong , Wan Xuhao , Robertson John , Zhang Zhaofu , Guo Yuzheng
Published: October 2023

Solid–solid interfaces play a critical role in determining the performance of materials and devices. However, both experimental and theoretical determinations of interface structures are very challenging. In this Letter, we develop a high-throughput interface prediction and generation (IPG) scheme to predict the atomic structure of interfaces. To demonstrate the performance of the IPG, we apply it to the β-Ga2O3/AlN interface, which has attracted a great deal of attention for its promising application in power devices. Six β-Ga2O3/AlN interfaces are screened from thousands of candidates with the minimum mismatch and area tolerance. All these interfaces are modeled to satisfy the electron counting rules and then optimized by the minimum hopping method. The band alignments at the β-Ga2O3/AlN interfaces are in accordance with the available theoretical and experimental results. The results provide the basis for designing optical and electronic devices based on β-Ga2O3/AlN interfaces.
Development of the test method for wind turbine blade subcomponent under combined bending and torsion loads
Authors: Wu Honghui , Qi Liangwen , Guo Naizhi , Shi Kezhong , Xu Jianzhong , Li Qingan , Zhong Xiaohui
Published: October 2023

The conventional full-scale wind turbine blade testing method is unable to study the detailed structural response of blades' key subcomponents under complex loads. Therefore, developing an efficient and reliable blade subcomponent testing method is of great significance for investigating the structural characteristics of blades. This paper develops an innovative blade subcomponent test method framework, which is capable of studying the structural response under combined bending and torsion load conditions. A high-fidelity finite element model corresponding to the framework that considers nonlinear factors is established. This study further investigated the influence of boundary conditions on the results. The results showed that the test method proposed in this paper is reasonable, and the experiment based on this method is successfully conducted. The contact nonlinearity and size effects will affect the accuracy of the test results, which can be avoided by adjusting the size of the clamp.
Crystallization of FAPbI3: Polytypes and stacking faults
Authors: Ahlawat Paramvir
Published: October 2023

Molecular dynamics simulations are performed to study the crystallization of formamidinium lead iodide. From all-atom simulations of the crystal growth process and the δ-α-phase transitions, we try to reveal the formation of various stack-faulted intermediate defected structures and report various polytypes of formamidinium lead iodide that are observed from simulations.
Dynamic density functional theory for sedimentation processes on complex domains: Modelling, spectral elements, and control problems
Authors: Roden Jonna C. , Goddard Benjamin D. , Pearson John W.
Published: October 2023

Modelling of many real-world processes, such as drug delivery, wastewater treatment, and pharmaceutical production, requires accurate descriptions of the dynamics of hard particles confined in complicated domains. In particular, when modelling sedimentation processes or systems with driven flows, it is important to accurately capture volume exclusion effects. This work applies Dynamic Density Functional Theory to the evolution of a particle density under diffusion, external forces, particle–particle interaction, and volume exclusion. Using a spectral element framework, for the first time it is possible to include all of these effects in dynamic simulations on complex domains. Moreover, this allows one to apply complicated no-flux, and other non-local, non-linear, boundary conditions. The methodology is also extended to control problems, addressing questions of how to enhance production set-up in industrially-motivated processes. In this work the relevant models are introduced, numerical methods are discussed, and several example problems are solved to demonstrate the methods’ versatility. It is shown that incorporating volume exclusion is crucial for simulation accuracy and we illustrate that the choice of boundary conditions significantly impacts the dynamics.
Optical characterization of high performance mirrors based on cavity ringdown time measurements with 6 degrees of freedom mirror positioning
Authors: Gutierrez N. , Degallaix J. , Hofman D. , Michel C. , Pinard L. , Morville J. , Battesti R. , Cagnoli G.
Published: October 2023

An instrument capable of measuring optical losses, transmission, and the radius of curvature of high reflectivity mirrors is presented. The measurement setup consists of two remote controlled hexapod systems with 6 degrees of freedom placed inside a vacuum enclosure. Mirror loss measurements are performed via the cavity ring-down time method using a linear resonant two-mirror Fabry–Perot cavity configuration. The use of high-precision positioning systems enables cavity loss mapping by transversely scanning the position of the cavity end mirror. Mirror surfaces of up to 30 mm in diameter can be scanned, and the cavity length can be tuned by 120 mm.
Stochastic generation in a Josephson-like antiferromagnetic spin Hall oscillator driven by a pure AC current
Authors: Slobodianiuk D. V. , Prokopenko O. V.
Published: October 2023

We numerically demonstrate that a pure time-harmonic bias AC current of a specific amplitude τf and angular frequency ωf can excite the chaotic magnetization dynamics in a Josephson-like antiferromagnetic (AFM) spin Hall oscillator (SHO) with biaxial magnetic anisotropy of an AFM layer. The nature of such a stochastic generation regime in a Josephson-like AFM SHO could be explained by the random hopping of the working point of the SHO between several quasi-stable states under the action of an applied AC current. We reveal that depending on the ωf/τf ratio several stochastic generation regimes interspersed with regular generation regimes can be achieved in an AFM SHO, which can be used in spintronic random signal sources and various nano-scale random signal devices, including the spintronic p-bit device considered in this work. The obtained results are important for the development and optimization of spintronic devices capable of generating and processing (sub-)THz-frequency random signals, which are promising for ultra-fast probabilistic computing, cryptography, secure communication, etc.
Growth and optical performance of short-period W/Al and polished W/Si/Al/Si multilayers
Authors: IJpes D. , Yakshin A. E. , Sturm J. M. , Ackermann M.
Published: October 2023

Short-period multilayer mirrors are used in wavelength-dispersive x-ray fluorescence to reflect and disperse elements in the O-Kα– Al-Kα range. In this work, we investigated sputter-deposited 2.5 nm W/Al with 20 periods. Our results show that W/Al is a poor reflector due to a combination of high interfacial roughness and strong W–Al intermixing. To address this, we introduced 0.5 nm Si seed layers at the W-on-Al and Al-on-W interfaces each consecutive period, while reducing the Al thickness from ∼2.0 to ∼1.0 nm. The Si seed layers significantly reduced interfacial roughness and W–Al intermixing, which led to an increase in the reflectance of the first Bragg peak at λ = 0.154 nm. To further reduce interfacial roughness, ion beam polishing of the top Si layer was applied at each period. The resulting structure of W/Si/Al/Si with ion beam polishing showed that the reflection coefficient of the first Bragg peak at λ = 0.154 nm was comparable to that of standard W/Si. These findings demonstrate the effectiveness of seed layers combined with polishing techniques in synthesizing smooth, high-reflectance multilayers containing two materials that are otherwise challenging to synthesize.
Influence of inner shear layer on the emergence of central recirculation zone in a V-shaped premixed swirling flame
Authors: Wang Qiuxiao , Ren Yongzhi , Gu Mingming , Yu Bowen , Feng Xiaoxing , Qi Fei , Xia Xi
Published: October 2023

This paper presents an experimental study on the emergence of the central recirculation zone (CRZ) in a basic V-shaped premixed swirling flame, using simultaneous measurement of particle image velocimetry and CH* chemiluminescence. Unlike most previous works that explored CRZ formation controlled by vortex breakdown (VB), the present experiment maintains a constant swirl intensity to rule out the influence of VB. We find that the CRZ characteristics and its emergence are strongly affected by the strength of the inner shear layer (ISL) surrounding the CRZ. However, the critical ISL intensity corresponding to CRZ emergence varies with the Reynolds number (Re) and the equivalence ratio (Φ). Upon employing dimensional analysis, the underlying mechanism can be interpreted with a non-dimensional parameter, Res=γmaxD/νs, defined based on the maximum ISL intensity (γmax), the exit diameter (D), and the kinematic viscosity (νs) of the burnt gas. The resultant γmaxD−νs regime diagram demonstrates the collapse of the critical Res value for various cases with and without CRZ. The Res mechanism explains the dependence of the critical ISL intensity on the equivalence ratio, further emphasizing the non-negligible roles of both the ISL intensity and the viscosity of the burned gas, in addition to VB, in determining the emergence of CRZ for V-shaped swirling flames.
Investigation on the kinetics of a diode-pumped plasma-jet type metastable argon laser
Authors: Liu Qingshan , Yang Zining , Wang Rui , Yang Weiqiang , Wang Hongyan , Xu Xiaojun
Published: October 2023

Diode-pumped rare gas lasers (DPRGLs) have the potential for high-energy laser output with high beam quality. The metastable concentration >1014 cm−3 and pump intensity >10 kW/cm2 are required in developing high-power and efficient DPRGLs. However, the kinetics of 1s and 2p levels (Paschen notation) under these conditions is unclear yet, particularly regarding the adverse effects of interference energy levels (e.g., 1s4 and 2p1–2p8). This study addresses this gap by measuring the number densities of 1s and 2p levels in a diode-pumped plasma jet metastable argon laser. The experiment was conducted with a much higher number density of 1014 cm−3 and a higher pump intensity of 12 kW/cm2 than our previous works. The results indicate that the adverse effect of 1s4 accumulation could be partially compensated, and the relative population distribution of 2p energy levels remained unchanged. However, the high gas temperature (>1000 K) caused a significant negative impact of high 2p levels (2p1–2p8), and the air environment weakened the effect of He collision relaxation.
Spin state and magnetic coupling in polynuclear Ni(II) complexes from density functional theory: is there an optimal amount of Fock exchange?
Authors: Manukovsky Nurit , Kamieniarz Grzegorz , Kronik Leeor
Published: October 2023

Reliable prediction of the ground-state spin and magnetic coupling constants in transition-metal complexes is a well-known challenge for density functional theory (DFT). One popular strategy for addressing this long-standing issue involves the modification of the fraction of Fock exchange in a hybrid functional. Here we explore the viability of this approach using three polynuclear metal-organic complexes based on a Ni4O4 cubane motif, having different ground state spin values (S = 0, 2, 4) owing to the use of different ligands. We systematically search for an optimum fraction of Fock exchange, across various global, range-separated, and double hybrid functionals. We find that for all functionals tested, at best there only exists a very narrow range of Fock exchange fractions which results in a correct prediction of the ground-state spin for all three complexes. The useful range is functional dependent, but general trends can be identified. Typically, at least two similar systems must be used in order to determine both an upper and lower limit of the optimal range. This is likely owing to conflicting demands of minimizing delocalization errors, which typically requires a higher percentage of Fock exchange, and addressing static correlation, which typically requires a lower one. Furthermore, we find that within the optimal range of Fock exchange, the sign and relative magnitude of Ni–Ni magnetic coupling constants are reasonably well reproduced, but there is still room for quantitative improvement in the prediction. Thus, the prediction of spin state and magnetic coupling in polynuclear complexes remains an ongoing challenge for DFT.
Linear instability of a two-dimensional viscoelastic liquid film under the coupling effect of electrostatic field and parametric resonance
Authors: Jia Bo-qi , Wang Ping , Yang Qi , Fu Qing-fei , He Bo-shu
Published: October 2023

A two-dimensional temporal linear instability analysis is performed for a charged liquid viscoelastic film on a vertically oscillating plane in the presence of an electrostatic field. The viscoelastic fluid, described by the Oldroyd-B model, is intended to be a Taylor–Melcher leaky dielectric, while the ambient gas is treated as perfectly dielectric. Results show that the oscillations induce parametric unstable regions. The parametric unstable regions can be superimposed on the inherent unstable region when the oscillation frequency is small because the frequency in the inherent unstable region is non-zero. The electric field has a complex effect on both inherent and parametric instabilities. The effect of the electrical relaxation time is dominated by the electrical Bond number and dimensionless distance. The relative permittivity has a destabilizing effect. However, the effects of electrical relaxation time and relative permittivity in the parametric unstable region are negligible. The viscosity and elasticity have non-monotonic effects on the inherent instability but have a monotonous effect on the parametric instability. The increase in Bond number has a stabilizing effect. The effect of density ratio is not constant in the inherent unstable region according to the electrical Bond number and Bond number. However, the increase of density ratio has a monotonously stabilizing effect on the parametric instability.
Numerical study on three-dimensional flow around a cylinder with perforated shrouds at different Reynolds numbers
Authors: Zhou Siqi , Liu Hongkang , Chen Rongrong , Zhang Shishang , Zhang Youjun , Li Zhuolun , Zhao Yatian
Published: October 2023

The perforated shrouds have been proposed to control cylinder flows, while the effects and mechanisms at different Reynolds numbers (Res) remain unclear. Three-dimensional numerical simulations are conducted in this paper to compare the aerodynamic performance of the flow around a smooth cylinder and a shrouded cylinder at Re of 3900 and 1.4×105. The results indicate that the drag of the perforated shrouded cylinder is reduced by 30.8% at the high Re, while increased by 26% at Re of 3900 compared with the smooth cylinder. Differently, the lift oscillations of the cylinder are greatly weakened by 83.3% at the Re of 3900 and 98.5% at the Re of 1.4×105, which implies the wake oscillations are nearly eliminated at the Re of 1.4×105. Further analysis exhibits the near wake region is elongated along the mainstream, with significantly recovered pressure. Especially, the greater pressure loss owing to outer shrouds even leads to the negative drag of the inner cylinder at the high Re. In addition, the incoming flow is broken up by outer shrouds, and different flow patterns appear in the gap. The discernible vortex pairs occur in the gap at the Re of 3900, while as Re increases to 1.4×105, the quantities of small-scale vortex weaken the impact on the inner cylinder. The shear layer characteristics are elucidated by Lamb vector curl and Kelvin–Helmholtz instabilities. The vorticity stretching and tilting in the shear layer of the shrouded cylinder is much weaker at the high Re. Generally, the energy for shear layer instabilities at low frequencies is diminished with the presence of perforated shrouds. However, the energy at higher frequencies is strengthened at the low Re.
Application of heliox for optimized drug delivery through respiratory tract
Authors: Farooq Umar , Riaz Hafiz Hamza , Munir Adnan , Zhao Ming , Tariq Ammar , Islam Mohammad S.
Published: October 2023

Understanding the transportation and deposition (TD) of inhaled particles in the upper respiratory tract is crucial for predicting health risks and treating pulmonary diseases. The available literature reports highly turbulent flow in the extrathoracic (ET) region during normal breathing, which leads to higher deposition of the drug aerosol in this region. To improve the targeted deposition of inhaled drugs, in the tracheobronchial airways, it is essential to understand the flow and particle transport dynamics and reduce the turbulence behavior at the ET region. The less-dense heliox gas could reduce the turbulence behavior at the ET; however, the knowledge of heliox inhalation therapies in drug aerosol TD remains underachieved to realize the full potential for assisted breathing and drug delivery. Additionally, the impact of the inhalation of heliox mixed with other gases on particle deposition is missing in the literature. Therefore, this study aims to develop a mixture model to advance the knowledge of inhalation therapy. A heliox (78% helium and 22% oxygen) and a mixture of heliox and air are used to understand the flow behavior and particle TD in airways. The impact of different inhalation and Stokes numbers on the deposition efficiencies in the ideal and age-specific upper airways is studied. The study reports that less-dense heliox gas has lower turbulence intensity and results in lower deposition efficiency in the G3–G5 lung airways compared to air and mixture inhalations. Moreover, slightly higher deposition efficiencies during mixture inhalation as compared to air inhalation are found in the upper airways. The deposition patterns of different inhalations obtained in this study could help improve targeted drug delivery into the upper and deeper lung airways.
Aerodynamic effect on atomization characteristics in a swirl cup airblast fuel injector
Authors: Fang Chuanyu , Liu Yushuai , Wang Shaolin , Liu Cunxi , Liu Fuqiang , Yang Jinhu , Wang Kaixing , Mu Yong , Xu Gang , Zhu Junqiang
Published: October 2023

To investigate the influence of swirling air flow field on the spray characteristics and the droplet behaviors of the swirl cup airblast fuel injector, a single swirler cup and a double swirlers cup airblast injector were operated in a wide range of fuel mass flow rates (mf) and relative air pressure drops (ΔPa). Various laser based diagnostics, including planar Mie scattering, phase-Doppler particle analyzer, and high speed particle imaging velocimetry, were employed to provide the information of spray angle, droplet Sauter mean diameter (SMD), droplet velocity, and air flow velocity. The results show that the air flow field was characterized by central toroidal recirculation zone (CTRZ), the double swirlers cup airblast injector generated stronger CTRZ than single swirlers cup airblast injector. The spray characteristics and the droplet behaviors with different size classes were significantly affected by the air flow field. The larger droplets (25–100 μm) with higher initial momentum were likely to keep its velocity when passing through CTRZ, when the mf increased, more large fuel droplets could pass through the CTRZ and expanded to both sides, resulting an increase in a spray angle. On the other hand, smaller droplets (<25 μm) with lower initial momentum were trend to be enrolled by the CTRZ; therefore, the spray droplets at lower mf were confined in the CTRZ. These droplets trend to coalesce with each other resulting in an increase of SMD in this region.