bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating Facial Muscle Physiology Following Soft Tissue Filler Injections—A Surface-derived Electromyographic and Skin Vector Displacement Analytic Study
Authors: Casabona Gabriela , Frank Konstantin , Zeng Rui , Cotofana Sebastian , Alfertshofer Michael , Weinmann Charlotte , Moellhoff Nicholas , Kaye Kai O.
Published: June 2024

The use of hyaluronic acid-based soft tissue fillers has often been reported to modulate the muscle, that is, to cause myomodulation. To our knowledge, there has been so far no scientific study investigating the potential of hyaluronic acid-based soft tissue fillers to modulate or actually alter the function of facial muscles. To further assess this three-dimensional (3D) surface imaging and electromyography (EMG)-based prospective study investigated the changes of facial muscle contraction after injection of strategically placed hyaluronic acid-based soft tissue fillers to assess the actual validity of the term myomodulation. A total of 13 subjects with a mean age of 37.8 years (12 females, 1 male) were injected according to a predefined injection protocol. Surface EMG and 3D surface imaging were performed prior to the injection and 5 days after the injection. The results showed no significant change in the strength of the muscles (measured in μV) after injection of hyaluronic acid-based soft tissue fillers. However, horizontal and vertical skin displacement upon contraction of the zygomaticus major muscle changed significantly between baseline and follow-up, with a mean horizontal skin displacement increase from 3.2 to 4.1 mm. Upon contraction of the depressor anguli oris muscle, the horizontal skin displacement did not change significantly (2.15 vs. 2.05 mm), while vertical skin displacement increased significantly from 2.9 to 4.3 mm. The modification of the surrounding tissue caused an alteration of the vectorial skin displacement upon contraction of the muscle. A potential explanation could be the increased distance between the origin and insertion of the muscle due to the material deposition in the proximity of the relevant facial muscles, leading to a change of contraction vector.
Juvenile Nasopharyngeal Angiofibroma: A Series of 96 Surgical Cases
Authors: Felippu Alexandre Wady Debes , Fontes Erica Batista , Felippu André Wady Debes , Ellery Bruna Coelho , Oliveira Ana Carolina Silveira de , Guimarães André Vicente , Cascio Filippo , Felippu Alexandre
Published: June 2024

Introduction Juvenile nasopharyngeal angiofibroma (JNA) is a benign vascularized tumor that affects almost exclusively male adolescents. Surgery is the treatment of choice for JNA.

Objectives The present study is a 42-year retrospective review of a series of JNA cases treated surgically without previous embolization.

Methods The present is a retrospective, descriptive study based on medical records of 96 patients with JNA who underwent microscopic or endoscopic excision without previous embolization from 1978 to 2020 in a single institution. The patients were categorized according to the Andrews et al. stage, and data were collected on age, gender, tumor staging, surgical approach, affected side, and outcome.

Results All patients were male, with an average age of 17 years. The predominant tumor stage consisted of type II, with 52.1%. A total of 33.3% of the patients were submitted to the microscopic technique and 66.7%, to the endonasal technique. The rate of intraoperative blood transfusion was of 17.7%.

Conclusion The present study reinforces that resection of JNA in various stages is viable without previous artery embolization.
Variations of Tentorial Notch Anatomy in Autopsy and NCCT of Head Injury Patients to Correlate Its Impact over Brainstem—An Observational Study
Authors: Singh Anoop Kumar , Ojha Bal Krishna , Jaiswal Manish , Bajaj Ankur , Yadav Awdhesh
Published: June 2024

Background Tentorium cerebelli divide cranial cavity into supratentorial and infratentorial compartment. Tentorial notch is a gap in tentorium cerebelli located centrally and anteriorly, related to upper brainstem, first six cranial nerves, cerebrum, and cerebellum. The aim of this study was to analyze morphometric variation in tentorial notch anatomy in autopsy and computed tomography (CT) of head injury patients and to find out correlation between tentorial notch anatomy and uncal herniation and changes over brainstem surface in case of uncal herniation.

Materials and Methods Autopsy examination of head injury patients was done between July 1, 2021, and Jan 31, 2023. Skull was opened in a standard manner and midbrain sectioned at the level of tentorial edge. Tentorial notch parameters (anterior notch width, maximum notch width, notch length, posterior tentorial length, apicotectal distance, interpedunculoclival distance) were measured using geometry compass and vernier caliper. These parameters were also measured on noncontrast computed tomography (NCCT) head of same patients. Evidence of uncal herniation was sought for in both NCCT head and autopsy examination. Impact of uncal herniation over brainstem in form of indentation over lateral surface of midbrain and macroscopic brainstem hemorrhage was noted.

Results In 65 autopsy cases, there were 56 male and 9 female specimens; their mean age was 40.63 ± 16.78 years (range: 7–86 years). The most frequent type of tentorial notch observed in our study was typical type (32.30%). Relative frequency of uncal herniation was present predominantly (75%) in large type of tentorial notch and least (20%) in small type of tentorial notch. A significant correlation (p-value < 0.01) was found between uncal herniation and indentation over lateral surface of midbrain, while no significant correlation (p-value > 0.05) was found between uncal herniation and macroscopic brainstem hemorrhage in autopsy specimens.

Conclusion The results of our study provide a baseline data about tentorial notch anatomy and it may facilitate neurosurgical decision making as well as help in deciding the best trajectory for lesions approaching in the vicinity of the tentorial notch
Early Physical Therapy Management of a Patient with Diaphragmatic Eventration Following Diaphragmatic Plication: A Case Report
Authors: Prajapati Dipika , Ashok Abeeshna
Published: June 2024

Diaphragmatic plication is the recommended surgical procedure for the treatment of diaphragmatic eventration in those who have failed conservative care. The present case report describes a 63-year-old male patient who presented with breathlessness on exertional activities. Chest X-ray and Computed Tomography (CT) of the thorax revealed diaphragmatic eventration on the right side. After failed conservative management, the patient underwent diaphragmatic plication surgery and was followed up with postoperative physical therapy management. Physical therapy intervention was started from 3 days postsurgery and was continued for 1 week. The treatment goals focused on reducing breathlessness, reducing pain on the incision site, preventing postoperative complications, and improving functional capacity. The present study highlights the benefits of early physical therapy interventions including incentive spirometer, dyspnea relieving techniques, Transcutaneous Electrical Nerve Stimulation (TENS), and light- to moderate-intensity aerobic exercises in the patient after plication surgery.
The Crucial Role of Psychosocial Research for Patients and Caregivers: A Narrative Review of Pediatric Psycho-Oncology Research in India
Authors: Namjoshi Shraddha
Published: June 2024

The focus of pediatric cancer research in India has largely been medical and clinical, with little focus on psycho-oncological aspects. Receiving a cancer diagnosis can be life altering for both the patients as well as their families and points to a need for psycho-oncological research. The present narrative review examined original articles on pediatric psycho-oncology research conducted in India particularly in the past two decades. There is promising research in various domains such as survivorship and quality of life, patient needs and psychosocial concerns, communication between health care providers, patients, and caregivers, parent and caregiver needs including psychosocial support and information, as well as some intervention-based studies. With much of the research being conducted within clinical setups through surveys and retrospective data, psychosocial issues faced by patients and their families are discussed along with physical, logistical, and financial concerns, while forays into intervention-based research are still in primary phases but show potential in terms of outcomes and feasibility. There is need for more methodologically rigorous research rooted in strong theoretical foundations, culturally sound models, and with evidence-based examination of all stages and stakeholders involved in providing and receiving care in pediatric cancer.
Attitudes of Health Care Providers in Relation to Disability, Saudi Arabia
Authors: Woodman Alexander , Jaoua Nizar , Al-Jamea Lamiaa H. , Balilla Jeffhraim , Al Zahrani Eidan M. , Al-Ansari Rehab Y. , Qahtani Salem H.
Published: June 2024

Background Among the main barriers that prevent people with disabilities from seeking help and support are negative attitudes of society in general and health care professionals in particular. However, only a few studies looked into the attitudes of health care providers toward people with disabilities in Saudi Arabia. This study aimed to investigate the attitudes of health care providers in relation to people with disabilities.

Participants and Methods The attitudes toward disabled persons (ATDP) scale was administered among n = 1,033 health care providers in the Eastern Province of Saudi Arabia. The data were analyzed using JASP version 19 and Orange 3.26.0. Demographic data were analyzed using dummy encoding.

Results The mean ATDP score for 1,033 respondents was 58.03 (p = 0.000). Multiple linear regression analysis showed that respondents aged 24 to 25 years have significantly less positive attitudes, compared to participants aged 18 to 20 years (p = 0.004). No sufficient evidence was found whether marital status significantly affects attitudes toward people with disabilities. In contrast, participants with three or more children have a significantly (p = 0.014) less positive attitude compared to those who do not have children.

Conclusion This study found that, overall, health care professionals had slightly negative attitudes, according to the ATDP scale. However, younger respondents and those without children were more positive. Future research is recommended to collect more data on the significance of having children and its association with attitudes toward disabilities. More educational programs are recommended that can increase attitudes and awareness about people with disabilities.
Assessment of Knowledge on Cervical Cancer among Women with a View to Develop Information Booklet
Authors: Naik Chetan , Monteiro Priya Jyothi
Published: June 2024

Introduction Cervical cancer manifests in the cervix cells, the lower part of the uterus connecting to the vagina. Similar to other cancers, the exact cause of cervical cancer remains uncertain and idiopathic. However, it is established that the human papilloma virus plays a significant role in initiating cellular changes in the cervix. In India, the lack of cancer awareness and screening facilities results in many women presenting at an advanced and deadly stage of the disease, negatively impacting their prognosis and clinical outcomes.

Methods A total of 255 women aged between 18 and 45 years, who were either patients or accompanying bystanders at a tertiary care hospital, were selected using purposive sampling technique.

Statistical Analysis Descriptive statistics were used to represent the sociodemographic characteristics levels. Association of sociodemographic variables levels is determined using chi-squared test.

Results The mean age of the participants was 31.83 ± 6.83 years, majority (162 [63.5%]) were living in a rural area, most (175 [68.6%]) of the participants were married, majority (254 [99.6%]) of the subjects were not having any family history of cervical cancer, most (202 [79.2%]) of the participants were having a single sexual partner, majority (108 [42.4%]) were not having any information on cervical cancer, most (134 [52.5%]) of the participants were unaware of cervical cancer screening, 39 (15.3%) were aware but delaying, 26 (10.2%) were aware, 17 (6.7%) were aware but not decided to do, 16 (6.3%) were aware but undecided, and 21 (8.2%) were in “others” category.

Conclusion Although women are having good knowledge and positive attitude toward cervical cancer screening and prevention, still there is a gap to transform it into practice. There is a need for more educational programs to connect identified knowledge slits and uplift regular practice of cervical cancer screening.
Retinaculum Grafts in Scapholunate Ligament Reconstruction: A Systematic Review
Authors: Estermann Lea , Yong Melodi , York Blair S. , Tham Christopher Y. , Onggo James , Tham Stephen K.
Published: June 2024

Background Several surgical techniques for the treatment of the irreparable chronic scapholunate (SL) ligament disruption, without arthritis, have been described using tendon grafts. An alternative technique is the use of retinaculum grafts. A systematic review of the biomechanical and histological properties of the bone–retinaculum–bone (BRB) graft and the clinical results of its use in SL ligament reconstruction was performed.

Materials and Methods After abstract screening of 353 articles, a total of eight studies (five laboratory and three clinical) were included.

Results Five cadaveric studies showed a lower load to failure and lower stiffness of the BRB compared with the scapholunate interosseous ligament. In patients with dynamic SL instability, treatment with BRB graft resulted in pain relief and an improvement in grip strength but with a reduced range of motion. Radiologically, no SL widening was found 18 months after surgery but with a slight increase after 12 years. The three clinical studies in this review have a level of evidence of 4. There were no studies on graft incorporation and remodeling.

Conclusion There is insufficient clinical, histological, and biomechanical data available on the use of BRB grafts for SL ligament reconstruction.
The Role of Bone Grafting in Corrective Osteotomy of Distal Radius Malunions
Authors: Paul Ryan , Persitz Jonathan , Khan Shawn , MacDougall Michael , Chan Andrea
Published: June 2024

Background It remains unclear whether bone grafting is required during corrective osteotomy of the distal radius. The goal of this systematic review is to determine the union, revision, and complication rates of bone grafting techniques associated with extra-articular corrective osteotomy for dorsally malunited distal radius fractures treated with volar plating.

Questions Is bone grafting in distal radius corrective osteotomy associated with increased rates of bone union and reduced rates of revision surgery and complications?

Methods A comprehensive search of the MEDLINE, Embase, and Cumulative Index to Nursing and Allied Health Literature databases was completed for studies reporting clinical outcomes of extra-articular corrective osteotomy for dorsally malunited distal radius fractures treated with volar plating.

Results A total of 13 studies, with 14 intervention arms and 236 patients, were included. Bone grafting techniques consisted of autograft (6 studies, n = 93), synthetic bone grafts (2 studies, n = 38), allograft (1 study, n = 14), or no grafting (5 studies, n = 91). The overall union rate was 97%, and the mean time-to-union was 12.0 weeks. Larger corrections of dorsal tilt and ulnar variance were performed in the autograft and allograft groups. Complication and revision rates were highest in the synthetic group, 45 and 26.3% respectively.

Conclusion Grafting in extra-articular corrective osteotomy for dorsally angulated distal radius malunions treated with volar plating is not associated with an improved union rate in the literature. However, larger corrections were achieved in both the autograft and allograft groups compared to the no-graft and synthetic groups, resulting in similar union rates. Synthetic bone grafting was associated with the highest complication and revision rates. Future comparative prospective trials and proper documentation of whether cortical contact was present or absent are required to assess whether bone grafting warrants consideration in more advanced deformities.

Level of Evidence IV.
14.14 2H-1-Benzopyrans and 4H-1-Benzopyrans
Authors: Xiao X.
Published: June 2024

2H-1-Benzopyrans and 4H-1-benzopyrans are a significant class of heterocyclic compounds that exist widely in plants, including edible vegetables and fruits, and possess a wide range of biological and pharmacological activities. Hence, these compounds have high potential in pharmaceutical discovery. Reviewed herein are the classical strategies to access 2H-1-benzopyran and 4H-1-benzopyran scaffolds.
20.1.5 Acid Fluorides (Update 2023)
Authors: Ouellet-Du Berger M.-R. , Paquin J.-F.
Published: June 2024

This review is an update to the earlier Science of Synthesis contribution describing methods for the preparation of acid fluorides, and focuses on papers published in the period 2007–2022. Improvements sought to the scope of available methods are, amongst others, higher substrate tolerance, lower toxicity and availability of reagents, and compatibility with one-pot amide synthesis.
An attention-based bilateral feature fusion network for 3D point cloud
Authors: Hu Haibing , Liu Hongchun , Huang Yecheng , Li Chenyang , Zhu Jianxiong
Published: June 2024

The widespread use of deep learning in processing point cloud data promotes the development of neural networks designed for point clouds. Point-based methods are increasingly becoming the mainstream in point cloud neural networks due to their high efficiency and performance. However, most of these methods struggle to balance both the geometric and semantic space of the point cloud, which usually leads to unclear local feature aggregation in geometric space and poor global feature extraction in semantic space. To address these two defects, we propose a bilateral feature fusion module capable of combining geometric and semantic data from the point cloud to enhance local feature extraction. In addition, we propose an offset vector attention module for better extraction of global features from point clouds. We provide specific ablation studies and visualizations in the article to validate our key modules. Experimental results show that the proposed method performs superior in both point cloud classification and segmentation tasks.
Sandwiched structure for temperature compensated laterally excited bulk wave resonators based on lithium niobate film
Authors: Tian Yahui , Du Rufan , Zhang Qiaozhen , Cai Feida , Li Honglang , Lu Qipeng
Published: June 2024

Recently, lithium niobate thin film laterally excited bulk wave resonators (XBARs) have attracted much attention because of their advantage of high frequency and outstanding electromechanical coupling factor (K2) enabling wide filter bandwidths. These can satisfy the increasing 5G communication demand. However, their large temperature coefficient limits their development to some extent. To improve their temperature stability with little K2 reduction, this paper has proposed a sandwiched structure for temperature compensated XBARs (TC XBARs). This structure includes the top silicon dioxide (SiO2) layer and the bottom SiO2 layer. One layer can improve temperature stability, and the other layer can increase K2. The optimized XBARs have a temperature coefficient of frequency (TCF) of −90.77 ppm⁄°C. The common two-layer TC XBARs can achieve a TCF of −22 ppm⁄°C sacrificing K2 to 8%. However, the proposed sandwiched TC XBARs can achieve a K2 of 12.15 and a TCF of −28.94 ppm⁄°C simultaneously, with a large FoM. Meanwhile, spurious modes can be suppressed in the sandwiched structure. Thus, this sandwiched structure can provide a good solution for the high performance of XBARs.
Turbulence image correction using focused light field camera
Authors: Wang Yan , Sun Quan , Han Kai
Published: June 2024

Under turbulent conditions, the images of objects may be severely blurred and become unrecognizable because of the complex aberrations introduced by turbulence. Using adaptive optics (AO) to compensate for these wavefront aberrations can theoretically solve the problem of image blurring under turbulent conditions. However, due to its small field of view and high cost, the AO system is difficult to widely use. In recent years, using the technology of light field photography to correct turbulence images has been proposed. However, the current studies are either based on the structure of the non-focused light field camera, which makes it hard to achieve good image quality, or on the need to redesign the core sensor of the non-focused light field camera, which greatly increases the cost and complexity. We believe that the structure of a focused light field camera has a good potential for turbulence image correction and propose a new method of achieving a corrected focused image using a focused light field camera in this paper. We propose to use phase estimation instead of depth estimation for a focused light field camera and phase maps instead of a depth map as the basis for achieving a focused image. By the proposed method, a corrected focused image with a large field of view under turbulent conditions is achieved without using independent wavefront correction devices or redesigning the light field camera. The experiments are given to verify the effectiveness of the proposed method under strong turbulent conditions in the laboratory and real turbulent conditions in the outdoors. The proposed method in this paper provides a new and low-cost solution for image correction for optical imaging systems under turbulent conditions, so it has a high application value.
Defect detection and imaging using electromagnetic acoustic transducer with butterfly coil
Authors: Wang Chaoqun , Ma Jian , Bai Xue , Chen Jianwei
Published: June 2024

Electromagnetic ultrasonic detection technology utilizes the electromagnetic coupling method to generate and receive ultrasonic waves without a couplant, which is suitable for rapid detection. However, the detection can be affected by the spatial distribution of the acoustic field and the polarization direction of the shear wave, which can result in suboptimal detection performance. The acoustic field directivity of the shear wave generated by the butterfly coil electromagnetic acoustic transducer was measured using the transmission method. The data indicate that the acoustic pressure amplitude of the shear wave is maximized along the axis of the acoustic field, thereby meeting the requirements of synthetic aperture focusing technique imaging. We used the reflection method to detect the through-hole defects and investigated the effect of shear wave polarization direction. By comparing the experimental data and imaging results, it can be concluded that higher echo amplitudes are obtained when the polarization direction of the shear wave is perpendicular to the axis of the through-hole defects. Based on the explosive reflection model, the frequency domain phase shift migration (PSM) method converts the time-domain signal to the frequency domain for processing and uses a phase-shift factor for layer-by-layer imaging. We used the PSM method to process the experimental data, which not only produced high-resolution images but also had a high computational speed.
A phase-error immune approach for measuring transport AC loss by determination of minimum compensated voltage
Authors: Wei Liangyu , Liu Cong , Wang Zeji , Zhou Jun , Zhang Xingyi
Published: June 2024

Alternating current (AC) loss measurement is crucial for the theoretical evaluation and optimization in the fabrication of superconducting AC devices. Lock-in amplifier based on the lock-in phase is commonly adopted and inevitably involves with phase error. In this work, a novel approach for measuring transport AC loss by determining the minimum compensated voltage (MCV) was developed, in which the lock-in amplifier was removed. Since it just uses the voltage signal from an AC voltmeter, it is phase-error immune. Experimental results demonstrated that when using the lock-in amplifier, there existed a system error as the initial phase difference between the sampled (reference) and real current phases, which required careful compensation. In contrast, the phase error no longer needed to be considered by the MCV method, and the AC loss results were obtained much more conveniently with the relative error between the theoretical and the experimental of less than 5%. Finally, the AC loss of a coated conductor spiral wound on an epoxy bar was obtained using the presented approach, demonstrating its low cost, ease of operation, and high accuracy.
Measurement of early time outer laser beam reflection inside a cylindrical hohlraum at the National Ignition Facility
Authors: Chen Hui , Woods D. T. , Lemos N. , Rosen M. , Landen O. L. , Milovich J. L. , Schneider M. B. , Trosseille C. , Delora-Ellefson J. , Hardy M. , Hash N. , Hinkel D. E. , Holder J. , Izumi N. , Masters N. , Montgomery W. , Moody J. D. , Newman K. , Rogers S. , Ross J. S. , Smalyuk V. , Weber C. , Zobrist T.
Published: June 2024

In a National Ignition Facility (NIF) cylindrical hohlraum, any specular reflection (“glint”) off the wall from the outer cone (incident angle of 50° and 44° relative to the surface of the wall) laser beam will irradiate the capsule poles. If the glint power is sufficiently large during the picket (early time) of the laser pulse, it may seed high-mode perturbations on the capsule surface that can grow during the implosion. To quantify the glint power on the capsule during the picket by the outer beams, we performed dedicated experiments on NIF using a flat witness foil as a surrogate for the capsule in a half-hohlraum target. We found that the measured glint power is approximately comparable to simulations using a nominal electron conduction flux limiter of f = 0.15, and over an order of magnitude lower than that predicted using f = 0.03 in the wall. Based on our current understanding, we conclude that the glint from the outer beams plays an insignificant role in capsule drive asymmetry.
A new “gold standard”: Perturbative triples corrections in unitary coupled cluster theory and prospects for quantum computing
Authors: Windom Zachary W. , Claudino Daniel , Bartlett Rodney J.
Published: June 2024

A major difficulty in quantum simulation is the adequate treatment of a large collection of entangled particles, synonymous with electron correlation in electronic structure theory, with coupled cluster (CC) theory being the leading framework for dealing with this problem. Augmenting computationally affordable low-rank approximations in CC theory with a perturbative account of higher-rank excitations is a tractable and effective way of accounting for the missing electron correlation in those approximations. This is perhaps best exemplified by the “gold standard” CCSD(T) method, which bolsters the baseline CCSD with the effects of triple excitations using considerations from many-body perturbation theory (MBPT). Despite this established success, such a synergy between MBPT and the unitary analog of CC theory (UCC) has not been explored. In this work, we propose a similar approach wherein converged UCCSD amplitudes are leveraged to evaluate energy corrections associated with triple excitations, leading to the UCCSD[T] method. In terms of quantum computing, this correction represents an entirely classical post-processing step that improves the energy estimate by accounting for triple excitation effects without necessitating new quantum algorithm developments or increasing demand for quantum resources. The rationale behind this choice is shown to be rigorous by studying the properties of finite-order UCC energy functionals, and our efforts do not support the addition of the fifth-order contributions as in the (T) correction. We assess the performance of these approaches on a collection of small molecules and demonstrate the benefits of harnessing the inherent synergy between MBPT and UCC theories.
Efficient search for acetic acid synthesis pathway based on the bond disconnection process on Rh surface and Rh/metal oxide interface
Authors: Chishima Kenshin , Masuda Takumi , Sampei Hiroshi , Saegusa Koki , Hattori Sakuya , Sekine Yasushi
Published: June 2024

The interfacial structure between Rh and the metal oxide support (or promoter) is thought to play an essential role in the synthesis of C2-oxygenated compounds such as acetic acid (CH3COOH). However, due to the complexity of the interface structure, the CH3COOH synthesis pathway has yet to be explored theoretically at the metal/metal oxide interface. In this study, we examined the CH3COOH synthesis pathway at the Rh surface and Rh/metal oxide interface based on the systematic investigation of bond disconnection of the CH3COOH molecule. First, CH3COOH synthesis pathways that include small activation energy Ea(c) were explored on the Rh(111) and it was shown that the reaction pathways CH + CO(H) → CHCO(H) → CH2CO(H) → CH3COH → CH3COOH were found [the rate-limiting step (RLS) is the C=O bond connection with Ea(c) = 1.41 eV]. After that, the CH3COOH synthesis pathway at the Rh/ZrO2 interface was investigated, and it was found that the CH3COOH synthesis pathway via the acetyl (CH3CO) generated from Rh–CH3 and Rh–CO with an oxygen atom in Rh–CO interacted with Zr cation (the RLS was the C–C bond connection with Ea(c) = 0.73 eV). This study provides guidelines for the design of a rational active metal/metal oxide interface for C2 oxygenates synthesis.
Computation of transport properties of warm dense matter using Abinit
Authors: Blanchet Augustin , Recoules Vanina , Soubiran François , Tacu Mikael
Published: June 2024

The dynamics of an inertial confinement fusion capsule, or of a stellar or planet interior, obey a very similar set of equations: magneto-radiative-hydrodynamic equations. The solutions of these equations, however, depend entirely on the transport properties associated with the different materials at play. To properly model the dynamics of these systems, it is necessary to determine with high accuracy the transport coefficients of several materials over a large range of thermodynamic conditions. Experimental capabilities in this respect are still limited due to the nature of the microphysics at play and the extreme conditions involved. Numerical simulations are thus necessary, and in this respect, molecular dynamics simulations based on density functional theory offer exquisite possibilities to constrain the transport properties in the warm to hot dense matter regime. In this paper, we report the methodology used to extract different transport properties based on molecular dynamics performed with the software Abinit. The examples shown are based on the specific cases identified for the purpose of the second charged-particle transport code comparison workshop.
Void closure in a pulsed complex plasma in microgravity
Authors: Knapek C. A. , Mohr D. P. , Huber P.
Published: June 2024

A new experimental method for creating void-free complex (dusty) plasmas under microgravity conditions is presented. The method is based on a pulsed operation mode of a four-channel radio frequency generator for plasma sustainment. A dust cloud of micrometer-sized particles can be immersed in the bulk of a low temperature plasma under microgravity conditions. It typically contains a central volume depleted of particles—the void—that prevents the generation of large, continuous clouds. Experiments performed at different neutral gas pressures and discharge volumes during the microgravity phase of a parabolic flight show that the central void is closed completely once the pulsed operation mode is applied. The particle cloud shape and the density distribution within the cloud are practically independent of the pulse period within the investigated parameter range and mainly depend on the overall discharge parameters neutral gas pressure and discharge volume. This indicates that the pulsed operation of the plasma source does not introduce new physical effects on the particles aside from the void closure. The proposed method has great potential for future application in experimental facilities dedicated to fundamental studies of large three-dimensional, homogeneous complex plasma systems in microgravity.
Coherent molecular vibrational dynamics studied by a 10-fs laser pulse in comparison for selective and nonselective excitation
Authors: Hashimoto Sena , Yabushita Atsushi , Okamura Kotaro , Kobayashi Takayoshi , Iwakura Izumi
Published: June 2024

Various selective excitation methods for molecular vibrations have been developed based on the characteristics of the applied lasers. In the present work, we coherently and selectively excited molecular vibrations up to 3000 cm−1 by irradiation with a sub-10-fs laser pulse. The spectral shaping of this laser pulse enabled us to selectively excite only the target vibrational frequency range (of the model compounds acetonitrile and benzene). Furthermore, the coherent molecular vibrational dynamics were compared between selective and nonselective excitation. The coherence of the molecular vibration persisted until 2–3 ps after photoexcitation, with the lifetime of this coherence being independent of whether the coherent molecular vibration was selective or nonselective excitation.
Effect of nozzle contamination on microwave discharge cathode performance
Authors: Morishita Takato , Tsukizaki Ryudo , Nishiyama Kazutaka
Published: June 2024

An understanding of the degradation mechanism of a microwave discharge cathode is the key to extending the lifetime of microwave ion thruster systems. This study investigates the effect of nozzle contamination by sputtered Ag-polytetrafluoroethylene (PTFE) on microwave discharge cathode performance. The current–voltage characteristics were measured for nominal and contaminated (by PTFE spray with 0.2 µm thick or tape with 0.15 mm thick) cathodes. The contamination thickness and area on the nozzle were varied to investigate the characteristic differences. It was confirmed that the anode voltage increased by 20 V or more in the case of the contaminated cathode. The anode voltage was measured for the sputter-contaminated cathode to evaluate the effect of contamination under more realistic conditions. After 630 h of sputter-contamination operation, it is estimated that sputtered particles were deposited to a thickness of 77 µm at most, and the anode voltage increased by 8 V. The results show that the downstream surface of the nozzle is critical for maintaining cathode performance. The insulating coating formed by the sputtered PTFE may interfere with ion absorption and degrade electron emission capability. A theoretical model based on the extended Brophy model supports these results. This study provides important information for the use of PTFE-based materials around ion thrusters.
Improved weighted nuclear norm with total variation for removing multiplicative noise
Authors: Kong Jiyu , Liu Xujiao , Liu Suyu , Sun Weigang
Published: June 2024

This paper introduces an improved weighted nuclear norm with a total variation model tailored for removing multiplicative noise. The model incorporates a weight matrix to regularize the residual matrix, effectively leveraging image redundancy to differentiate various statistical properties of the noise. Since there is no guarantee of a unique solution, the model is reformulated as a linear equality constraint problem and decomposed into two subproblems. These are addressed by using the alternating direction method of multipliers and the split Bregman method, respectively. In addition, each alternative update step has a closed-form and convergent solution. After obtaining the denoised image in the log-domain, the recovered image is given by using the exponential function and bias correction. Experimental evaluations demonstrate the efficacy of our algorithms in enhancing image restoration quality.
Impingement of a liquid jet on an opposing gas jet
Authors: Wu Zhan , Xu Chenghao , Liu Haoyu , Deng Weiwei
Published: June 2024

In contrast to the existing research on the liquid jet colliding with a physical target to produce a single type of liquid sheet or bell, we used an opposing gas jet target to generate a series of diverse shapes of axisymmetric liquid films. Specifically, we experimentally investigated the outcome of a 0.4-mm diameter water jet impinging on an opposing gas jet of 0.3 mm initial diameter. Five different axisymmetric film shapes are identified for the experimental parameters explored in this work, and the momentum flux ratio (X) of the gas jet to the water jet is the dictating factor for the exact film shape: (i) X = 0: smooth bells that share the same shape and profile model with classic water bells of a liquid jet impacting a solid target. (ii) 0 < X < 0.4: crumpled bells being lifted off from the gas nozzle by a thin layer of squeezing gas flow that is quantifiable by the lubrication model. (iii) 0.4 < X < 0.9: transient bells with mildly wrinkled surfaces that undergo periodic cycles from closure to bursting at a gas Reynolds number of ∼2400. (iv) 0.9 < X < 1.4: turbulent parachutes with curved and rough shapes. (v) X > 1.4: turbulent sheets that are flattened and atomized by the relatively strong gas stream. This work demonstrated that an opposing gas jet is a simple yet versatile approach to achieving a rich collection of phenomena by diverting the liquid jet momentum in multiple ways. This investigation aims to explore and rationale the rich phenomenology of water bells resulting from the impingement of a water jet on a gaseous jet target.
Atomic and electronic structures of domain boundaries in LaTiO3 thin films
Authors: Qiao Beibei , Sun Ziyi , Jiang Yixiao , Yao Tingting , Jin Qianqian , He Neng , Tao Ang , Yan Xuexi , Yang Zhiqing , Chen Chunlin , Ma Xiu-Liang , Ye Hengqiang
Published: June 2024

Domain boundaries in perovskite oxides often exhibit abundant physical properties and phenomena. Here, epitaxial LaTiO3 thin films on (100) SrTiO3 substrates are prepared by pulsed-laser deposition. X-ray diffraction and transmission electron microscopy investigations reveal that the epitaxial LaTiO3 thin films have good crystallinity but a high density of domain boundaries. Atomic-scale scanning transmission electron microscopy observations reveal that two types of domain boundaries are formed in the LaTiO3 thin films. The type I domain boundaries are formed on the {100} crystal planes, while the type II domain boundaries on the {110} crystal planes. Electron energy-loss spectroscopy analyses suggest that the valence states of Ti ions at the type I domain boundaries are +3, while those at the type II domain boundaries are +4. First-principles calculations reveal that the bandgap decreases at both domain boundaries compared to the bulk. The carrier concentration at the type I domain boundaries is significantly higher than that of the bulk, while the carrier concentration at the type II domain boundaries is lower. These findings suggest that domain boundaries play an important role in tailoring the electrical properties of the LaTiO3 thin films, thereby promoting the potential applications and property modulation of related materials and devices.
On the transitional wake past a streamwise rotating prolate spheroid
Authors: Wu Yuxin , Yang Jianzhi , Andersson Helge I. , Chen JianYu , Zhu Xiaowei
Published: June 2024

Direct numerical simulations are performed to study the behavior of the wake behind a 5:2 streamwise rotating prolate spheroid. The Reynolds number Re = 1000 under different rotational speeds over a large range of 0≤Ω≤3 is considered, where Ω is the non-dimensional rotational speed based on the freestream velocity and the volume-equivalent diameter of the prolate spheroid. By successively increasing the rotational speed, seven distinct flow regimes were identified and explored: steady state, low-speed steady rotation state, axisymmetric state, high-speed steady rotation state, twofold rotational symmetrical state (TFRS), quasi-periodic vortex shedding state (QVS), and weakly chaotic state. Among these wake regimes, the TFRS regime is reported for the first time, and it can be interpreted as an outcome of the stabilizing influence of the spheroid's rotation acting to restore the wake structure to an axisymmetric state. It is found that the rotation of the prolate spheroid has a stabilizing effect under low rotational speeds. Furthermore, the coupling mechanism between the rotational double helical structure and vortex shedding in the QVS regime has been revealed. The results of this study contribute to closing the knowledge gap regarding the wake dynamics of a streamwise rotating prolate spheroid.
Dielectric microwave resonator with large optical apertures for spin-based quantum devices
Authors: Hamamoto Tatsuki , Bhunia Amit , Bhattacharya Rupak Kumar , Takahashi Hiroki , Kubo Yuimaru
Published: June 2024

We demonstrate a low-loss dielectric microwave resonator with an internal quality factor of 2.30×104 while accommodating optical apertures with a diameter of 8 mm. The two seemingly conflicting requirements, high quality factor and large optical apertures, are satisfied, thanks to the large dielectric constant of rutile (TiO2). The quality factor is limited by radiation loss, and we confirmed by numerical simulation that this radiation loss can be suppressed by extending the enclosure height of the resonator; the resonator can potentially achieve a dielectric loss-limited quality factor, exceeding 106. Using this resonator, we performed both continuous-wave (cw) and pulse electron spin resonance (ESR) spectroscopy on 2,2-diphenyl-1-picrylhydrazyl (DPPH) crystalline powder and P1 centers in a diamond crystal in a dilution refrigerator. The cw ESR spectroscopy demonstrated high-cooperativity and strong spin-resonator coupling with the DPPH and P1 centers, respectively, while the pulse ESR spectroscopy successfully measured longitudinal and transverse relaxation times. This optically accessible low-loss microwave resonator enables the implementation of a spin-based quantum device, such as a microwave-optical photon transducer.
Numerical study of flow past two square cylinders with horizontal detached control rod through passive control method
Authors: Kalsoom Shazia , Abbasi Waqas Sarwar , Manzoor Raheela
Published: June 2024

A two dimensional (2-D) numerical study is conducted through the lattice Boltzmann method for flow past two square cylinders with a detached control rod placed in the horizontal position of the channel. The range of Reynolds number (Re) is fixed at Re = 150, with the length (l) of the control rod varying from l = 0.1d–21d. First, we check the accuracy of grid points and the validity of the code for present problems by comparing the results with already available data in the literature. After that, we discussed the obtained results in terms of vorticity contour, drag and lift coefficients, and force statistics. In our study of flow structure mechanisms, we examined four types of flow regimes: a small length control rod, a small and moderate length control rod, a moderate length control rod, and a larger length control rod according to flow behavior. In force statistics, we calculated the values of CDmean, CDrms, CLrms, CDamp, CLamp, and St, respectively. The mean drag coefficient contains the smallest values at the largest length, i.e., l = 19 and 21d. The maximum value of CDmean is examined at the first cylinder (C1) as compared to the second cylinder (C2) at l = 2.25d, and it is 1.2789. The values of CDmean for C2 at the length of the control rod, l = 0.1d–1.25d, and at l = 21d are negative due to the effect of thrust. The value of the Strouhal number is the same for both cylinders C1 and C2, and its highest value is 0.1036. The pressure amplitude of the drag coefficient is maximum for C1, while the pressure amplitude of the lift coefficient is maximum for C2, and its value is 2.1569.
Electrohydrodynamic eigenfrequency and jetting frequency analysis via Lagrangian dynamical model
Authors: Yang Weili , Li Huayang , Duan Yongqing , Yin Zhouping
Published: June 2024

Electrohydrodynamic (EHD) printing has emerged as a promising technique for high-resolution additive manufacturing, but the frequency limits and optimal operating ranges for drop-on-demand EHD printing remain elusive. This lack of clarity has significant implications for printing efficiency and accuracy. Here, we present a theoretical model based on the Lagrange equation to calculate the eigenfrequency in EHD printing. Our study elucidates the dynamic relationships between the eigenfrequency and key process parameters (e.g., voltage, meniscus diameter, and center angle), and reveals the intrinsic relationship between the jetting frequency and the oscillation eigenfrequency, demonstrating that the jetting frequency is limited by the eigenfrequency. This conclusion has significant implications for the design of high frequency EHD printing systems; it highlights opportunities to increase the eigenfrequency by optimizing parameters such as meniscus radius/center angle. In addition, it is interesting to note that the high-order-mode jetting phenomenon can be utilized to break through the traditional frequency limit of the low-order mode. This work can serve as an instructive benchmark of the EHD printing frequency, which provides a basis for designing a high-frequency EHD printing system.
Effect of the yaw angle on the riblet performance
Authors: Park Jonghwan , Choi Haecheon
Published: June 2024

Direct numerical simulations are performed to investigate the effect of the yaw angle (α) on the drag-reduction performance by riblets in a turbulent channel flow. The yaw angles of α=0° and 90° correspond to the riblets parallel and perpendicular to the free-stream direction, respectively. It is well known that maximum drag reduction occurs at α=0°, and the drag-reduction performance by riblets is degraded with increasing α. We obtain the critical yaw angle below which drag reduction can be achieved and investigate the corresponding mechanism. From a parametric study, drag reductions are achieved for α<20°. As α increases, the form drag increases more rapidly than the skin-friction drag decreases, resulting in the increase in the total drag. At drag reducing and increasing yaw angles, the mean velocity profiles in wall units shift upward and downward, respectively, and the latter profile suggests that the drag-increasing riblet is similar to a rough surface. With increasing α, the wall-normal and spanwise velocity fluctuations and Reynolds shear stress increase, and stronger near-wall vortices are generated. By applying a scaling analysis to the momentum equation in the riblet-perpendicular direction and the FIK (Fukagata–Iwamoto–Kasagi) identity [Fukagata et al., “Contribution of Reynolds stress distribution to the skin friction in wall-bounded flows,” Phys. Fluids 14, L73–L76 (2002); Peet and Sagaut, “Theoretical prediction of turbulent skin friction on geometrically complex surfaces,” Phys. Fluids 21, 105105 (2009); Bannier et al., “Riblet flow model based on an extended FIK identity,” Flow Turbul. Combust. 95, 351–376 (2015)] to the riblet-parallel direction, the total drag is expressed as a linear function of  sin2α.