bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk Factors Associated With Facial Acne Scarring in Thai Patients With Acne: A Cross‐Sectional Study
Authors: Yan Chadakan , Phinyo Phichayut , Yogya Yuri , Chuamanochan Mati , Wanitphakdeedecha Rungsima
Published: November 2024

Background

One of the worst long‐term effects of acne is scarring, which leads to significant physical, psychological, and economic burdens. Limited studies have specifically studied the risk factors for acne scarring. This study aims to explore risk factors associated with facial acne scarring in Thai patients with acne.

Methods

Exploratory cross‐sectional risk factor research was conducted using an online questionnaire on Thai patients aged ≥ 18 years who were diagnosed with acne between September and December 2023. The primary objective was to identify significant determinants of acne scars in patients with acne, including sociodemographic factors, clinical factors of acne, lifestyle factors, dietary habits factors, and treatment factors. Univariable and multivariable logistic regression were used to identify significant risk determinants.

Results

Of 225 patients with 61.33% prevalence of acne scarring, acne scarring was found to be independently associated with the following variables: moderate acne (mOR 3.51, 95% CI 1.31–9.40, p = 0.012) or severe‐to‐very severe acne (mOR 8.98, 95% CI 2.71–29.73, p < 0.001), sometimes squeezing and picking behaviors (mOR 2.69, 95% CI 2.71–29.73, p = 0.033), and postacne erythema (PAE) (mOR 4.46, 95% CI 1.96–10.14, p < 0.001).

Conclusion

The risk factors associated with acne scarring in individuals include the severity of acne, squeezing and picking behaviors, and experiencing PAE. One of this study's essential findings confirms that PAE is a notable component that could contribute to the development of acne scars. Early treatment of individuals at risk is crucial to reduce scar formation.
Ode to a Blackbird
Authors: Kahwagi Muriel N.
Published: November 2024

To access in written form, or even through a recording, that which was once performed in front of a live audience is akin to looking at an old picture. Both documents leave a trace of that which has passed, but they cannot recreate or capture the lived experience; they can only house the haunting. In the mid‐20th century’s swirl of audiovisual and written documentation of poetry, one may identify a pressing hunger or impulse to preserve an oral tradition which has historically, at least for the most part, been lost—and an attempt on behalf of poets to legitimize and record their life’s work. Sung poetry may be forgotten—it leaves no physical trace behind. In the end, it is the material that prevails, at least in the eyes of history.
Application of Action Observation Therapy in Swallowing Rehabilitation: A Randomised Controlled Study
Authors: Toksal Uçar Arzucan , Piri Çınar Bilge , Alıcıoğlu Banu , Bostan Geylan , Bilgin Sevil
Published: November 2024

Background

Action Observation Therapy (AOT) has emerged as a potential neurorehabilitation therapy to promote motor control for individuals with neurological dysphagia (ND), facilitating neural plasticity through activation of the mirror nervous system.

Objective

The aim of this study was to investigate the effect of AOT‐based dysphagia rehabilitation on suprahyoid (SH) muscle activation, swallowing difficulties, swallowing function, depressive symptom and quality of life in ND patients.

Methods

Thirty‐four participants with ND were randomly allocated to the AOT group (n = 17) or control group (n = 17). All participants underwent a 4‐week (5 sessions per week) conventional swallowing therapy. The AOT group watched exercise videos before doing these exercises, and the control group performed the same exercises without the videos. Surface electromyographic (sEMG) activation of suprahyoid muscles, Eating Assessment Tool 10 Turkish Version (T‐EAT 10) and Swallowing Ability and Function Evaluation (SAFE) for swallowing difficulties and swallowing function, Swallow Quality of Life Questionnaire (SWAL‐QOL) and Beck Depression Inventory (BDI) for quality of life and depressive symptom severity were evaluated.

Results

Post‐treatment SH amplitude level and T‐EAT‐10 scores were significantly lower in the AOT group compared to the control group (p = 0.001, p = 0.012). There was a significant improvement in SAFE after treatment in the AOT group (p < 0.05); however, there was no significant difference between the two groups (p > 0.05). Both groups showed similar improvement in quality of life and depression.

Conclusion

This study showed that AOT can be a good option for improving the SH muscle activation and dysphagia difficulties in ND patients.

Trial Registration

ClinicalTrials.gov identifier: NCT05782790
Effects of Mandibular Advancement Device on Genioglossus of Rabbits in Obstructive Sleep Apnea Through PINK1/Parkin Pathway
Authors: Ma Lishuang , Zhu Yahui , Zhang Zuo , Fan Dengying , Zhai Haoyan , Li Dongna , Kang Wenjing , Qiao Xing , Lu Haiyan , Liu Chunyan
Published: November 2024

Background

Early treatment of mandibular advancement device (MAD) reverses the abnormal changes resulting from obstructive sleep apnoea (OSA), but the underlying mechanism is not clear. We analysed the changes of genioglossus function before and after MAD treatment in OSA rabbits and explored the mechanism of mitochondrial autophagy.

Methods

Eighteen male New Zealand rabbits were randomised into three groups: the control group, Group OSA, and Group MAD. After successful modelling, all animals were induced sleep in supine positions for 4–6 h per day for 8 weeks. Cone beam computed tomography (CBCT) and polysomnography (PSG) were performed to record sleep conditions. The genioglossus contractile force and the levels of LC3‐I, LC3‐II, Beclin‐1, PINK1 and Parkin were detected in three groups. In vitro, C2C12 myoblast cells were cultured under normoxic or hypoxic conditions for 24 h, and then the changes in mitochondrial structure and accumulation of autolysosomes were detected by transmission electron microscopy (TEM).

Results

The contractile tension of the genioglossus in Group OSA was significantly lower than that in the control group. The ratio of LC3II/LC3I and the levels of Beclin‐1, PINK1 and Parkin were higher in Group OSA than that in the control group. And the abnormal changes were tended to be normal after MAD treatment. The mitochondrial structure was disrupted, and the number of autolysosomes increased in C2C12 after 24 h of hypoxia.

Conclusions

MAD treatment in male rabbits may decrease the contractile tension of the genioglossus and increase the level of mitochondrial autophagy caused by OSA. And the mechanism of mitochondrial autophagy was mediated by the PINK1/Parkin pathway in male rabbits.
Supplementing risk adjustment with high‐risk pooling using historical data for identifying the high risks
Authors: Oskam Michel , van Kleef Richard C. , van Vliet René C. J. A.
Published: November 2024

Many regulated health insurance markets with community‐rated premiums rely on risk adjustment (RA) to mitigate insurer‐incentives to risk select. However, insurers remain typically undercompensated for chronically ill enrollees. We use historical data on health spending and risk adjuster information to identify individuals undercompensated by the Dutch RA model of 2021 and find a selective group (1% of the population) with an average annual undercompensation of €6,050. We supplement the RA model with a risk sharing modality called high‐risk pooling (HRP) to organize residual‐based compensations towards insurers for the identified group to reduce the mean undercompensation to zero. The effects are evaluated on subgroups defined by chronic disease, finding a 42% reduction of their average undercompensation. Therefore, through compensating 1% of the population, the insurer‐incentives to select against chronically ill individuals substantially diminish. These results are compared to outlier‐risk sharing (reinsurance), proving HRP to be more effective at reducing selection incentives.
FLVAEGWO‐CNN: Grey Wolf Optimisation‐Based CNN for Classification of Olive Leaf Disease via Focal Loss Variational Autoencoder
Authors: Majikumna Kaloma Usman , Zineddine Mhamed , Alaoui Ahmed El Hilali
Published: November 2024

Agriculture is crucial for the economic stability of developing countries, with olive trees in the Mediterranean region providing significant benefits through olive oil and table olive production. However, olive trees are susceptible to diseases that threaten their productivity. Traditional methods of disease detection are time‐consuming and impractical on a large scale. Advances in artificial intelligence (AI) and machine learning now offer efficient solutions for rapid and accurate disease identification, which can enhance disease management and increase yields. This study introduces the FLVAEGWO‐CNN, an innovative deep learning model designed to improve classification accuracy of olive diseases, particularly in dealing with imbalanced datasets. The model integrates focal loss, variational autoencoders (VAE), grey wolf optimisation (GWO), and convolutional neural networks (CNNs) into a unified framework. The focal loss component addresses class imbalance by assigning more weight to hard‐to‐classify examples, while the VAE component improves data representation. GWO optimises the CNN's hyperparameters for robust performance. The FLVAEGWO‐CNN model was evaluated on a dataset with significant class imbalance, achieving an exceptional accuracy of 99.2% in binary classification and excelling in multiclass classification, particularly in recognising minority classes like ‘Aculus olearius’. The results suggest that this model outperforms existing models and provides a viable solution for imbalanced datasets in classification tasks. To ensure the model's validity, further investigation into potential challenges like overfitting and generalisability is necessary. Future work will focus on validating the model across diverse datasets and refining its architecture. The FLVAEGWO‐CNN model sets a new standard for accuracy and reliability in deep learning‐based disease classification, with implications for various applications, including medical diagnosis and fraud detection.
Implementation of the EU's geographical indications in CETA and JEFTA: EU‐Phoria or GI‐mmick?
Authors: Kennis Anke , Volkov Anastasia
Published: November 2024

Over the last two decades, the EU's foreign trade strategy shifted diametrically from the multilateral World Trade Organization to the bilateral free trade agreements (FTA) route. Accompanying this shift, the EU's regulatory ambitions became more apparent, as can be gleaned from its strategy documents. The main question is whether the EU is succeeding in effectively exporting or promoting its regulations. In this paper, we combine the two disciplines of law and international relations to gauge the EU's success in achieving its external regulatory goals through FTAs. The EU is described in the political science literature as a regulatory power which is trying to promote or export its regulations outside its own jurisdiction. Using two case studies of the recent EU FTAs with Canada and Japan, we conduct a rigorous legal analysis of these FTA texts as well as their implementation in the local jurisdiction by focusing on the area of Geographical Indications (GI). These regulations are compared with the EU's goals mentioned in its strategy documents and from interviews with EU representatives involved in the FTA negotiations. Our results show that the EU has been moderately successful in both FTAs in achieving its general goals such as equal protection for foodstuffs and alcoholic drinks, ex officio protection, and the clawback of some generic names. Overall, the EU was most successful in getting Japan to embrace an EU‐inspired sui generis GI system, whereas Canada showed less leniency and favoured its trademark system.
Tundra plant communities along the mesotopographic gradient in NE Finland
Authors: Kuusisto Inka , Huttunen Sanna , Virtanen Risto
Published: November 2024

In this study, we describe plant communities along the mesotopographic gradient in the low‐elevation subcontinental mountains of NE Finland (Utsjoki region). We sampled vascular plants, bryophytes and lichens along 18 mesotopographic ridge‐snowbed transects comprising a total of 180 plots. We used non‐metric multidimensional scaling (NMDS) ordination with envfit to explore the differentiation of plant communities in relation to mesotopography, elevation, rock cover, cover of bare ground, snowbed size and snowmelt time. The classification of communities was performed using DIANA clustering. Plant communities were differentiated along the mesotopographic gradient, snowmelt time, elevation and rock cover. The DIANA analysis distinguished seven clusters corresponding to the following communities: Betula nana–Lichenes heath, Empetrum–Myrtillus–Stereocaulon heath, Empetrum–Pleurozium–Lichenes heath, graminoid‐rich snow‐protected heath, Oreojuncus trifidus–Avenella flexuosa snow‐protected heath, Polytrichastrum sexangulare–liverwort snowbed, and Salix herbacea–Kiaeria starkei snowbed. Because of the strong impact of snowmelt time on plant community structure and distribution of communities, it is likely that climate change‐induced changes in snow conditions are affecting tundra vegetation and especially snowbeds are threatened. Snowbed communities in the Utsjoki region roughly align with previously described vegetation associations of mountain areas in NW Europe. The assignment of the graminoid‐rich snow‐protected heath community remains uncertain.
Spectrum of Craniofacial and Oral Malformations in China, a Multicenter Study
Authors: Duan Xiaohong , Zhu Yulong , Zheng Shuguo , Song Yaling , Wang Wenmei , Chen Dong , Zhao Zhenjin , Pan Yongchu , Chen Zhuo , Zhang Tingting , Huang Yongqing , Ren Liling , Ma Dandan , Wang Weihong , Huang Shengbin , Song Qinggao , Wang Baisheng , Zheng Yan , Li Jiang , Wang Jianhua , Zhang Yanli , Guo Xinyue , Ruan Wenyan , Wang Jing , Gong Zhongcheng , Chang Xiaofeng , Yuan Zhenglin , Wang Fu , Tian Guangqing , Meng Jing , Bao Zhexuan , Li Lin
Published: November 2024

Objective

Craniofacial and oral malformations (COMs) represent an important class of human developmental disorders with profound implications on the anatomical structure, appearance, and various physiological functions. In this study, we aimed to define the spectrum of COMs and analysis its features or possible influencing factors to improve the surveillance and control of the disease.

Materials and Methods

We organized a multicenter survey of COMs from 19 hospitals in 14 provinces. The clinical data of COM cases were collected from the electronic medical records system, cleaned and aggregated for analysis.

Results

A total of 90,895 COM cases with 76 types of diseases were identified from 34,649,545 hospital population. The four most common COMs were supernumery teeth (62.64%), cleft lip and palate (28.53%), microdontia (2.86%), and tooth agenesis (1.70%). The remaining 72 diseases were detected in 3881 cases and were considered to be rare COMs. Moreover, 84.72% of rare COMs also manifested as other malformations or dysfunctions of the bone, skin and other tissues.

Conclusions

COMs exhibit age and gender distribution patterns, have multiple types, and significant dental malformations. The diagnostic criteria and registration practices for COMs influence their reported prevalence and temporal trends, necessitating future improvements.
Uptake of eye care services in South India: Retrospective mapping of self‐reported barriers using the Theoretical Domains Framework
Authors: Yelagondula Vijay Kumar , Marmamula Srinivas , Varada Rajashekar , Subramanian Ahalya , Lawrenson John G.
Published: November 2024

Introduction

Understanding barriers to seeking eye care and providing evidence‐based theory‐informed solutions can improve the uptake of eye care services. Therefore, in this cross‐sectional study, we aim to report and analyse barriers to seeking eye care services among individuals with vision impairment in the Akividu region of Andhra Pradesh, India.

Methods

Out of the 3000 enumerated participants, a total of 2587 were examined. All participants with vision impairment were asked to report barriers for not seeking eye care despite noticing reduced vision using a validated questionnaire. The reported barriers were mapped to the theoretical domains framework (TDF) to explore potential individual and environmental influences on the uptake of eye care services.

Results

Barriers to seeking eye care services are most frequently mapped to the ‘beliefs about capabilities’, ‘environmental context and resources’ and ‘social influences’ domains of the TDF. The most frequently reported barrier was ‘aware of the problem but can manage’ (beliefs about capabilities), expressed by 43.4% (n = 156) and 55.7% (n = 337) of participants with distance and near vision impairment, respectively. ‘No one to accompany’ for an appointment (social influences) was a significant barrier for participants with distance vision impairment (n = 44, 12.2%) in comparison to participants with near vision impairment (n = 19, 3.1%). Additionally, fear of losing eyesight or operation or consultation (emotion) was a major deterrent for seeking eye care services, particularly among participants with distance vision impairment (n = 31, 8.6%) when compared with near vision impairment (n = 17, 2.8%).

Conclusion

The uptake of eye care services is influenced by a complex set of interacting factors. Identification of potentially modifiable target behaviours provides an opportunity to develop theory‐informed solutions to improve uptake of services and prevent avoidable vision loss.
Total Hip Arthroplasty Using the Conjoined Tendon‐Preserving Posterior Approach: The Modified Posterior Approach with a Minimum of 2‐Year Follow‐Up
Authors: Ozawa Yuto , Osawa Yusuke , Seki Taisuke , Takegami Yasuhiko , Iida Hiroki , Funahashi Hiroto , Imagama Shiro
Published: November 2024

Purpose

The conjoined tendon‐preserving posterior (CPP) approach is a modified posterior approach for total hip arthroplasty (THA) that preserves the short external rotator muscles and most ischiofemoral ligaments. The objective of the present study was to compare the short‐term clinical outcomes, complications, and imaging evaluations of CPP and posterior approaches in THA.

Methods

This retrospective study included 83 patients from May 2018 to September 2021: 36 patients with 42 hips who underwent THA with the CPP approach (CPP group) and 47 patients with 60 hips who underwent THA with the standard posterior approach (PA group) with a minimum of 2 years of follow‐up. Assessment tools included operative times, blood loss, preoperative and last follow‐up Harris Hip Scores (HHS), postoperative complications, and implant placement angles between the groups. Statistical analysis was performed using chi‐square tests and T‐tests.

Results

The CPP approach had a significantly longer operative time and greater blood loss compared to the PA group. Preoperative and postoperative HHS were not significantly different between groups. Considering complications, the PA group had one case each of dislocation and infection, and the CPP group had two cases of sciatic nerve palsy, but the difference was not significant. Cup anteversion, inclination and stem anteversion were not significantly different between groups.

Conclusion

Functional outcomes, complication rates, and implant placement angles were comparable with the posterior approach, and the CPP approach has the potential to reduce postoperative dislocations. However, careful attention should be paid to sciatic nerve palsy during early initiation of the CPP approach, and this study did not demonstrate that the CPP approach was clearly superior to the posterior approach.
Economic Foundations of Contraceptive Transitions: Theories and a Review of the Evidence
Authors: Karra Mahesh , Wilde Joshua
Published: November 2024

We review the foundations of the economic development–contraception nexus, focusing on the pathways through which economic factors drive contraceptive adoption and change. We investigate the channels through which the relationship between economic development and contraceptive dynamics is mediated. Using global data, we document the correlations between economic development and contraception transitions over time and across geographies. We briefly examine the evidence of the role of fertility, both desired and realized, as a central pathway through which the relationship has been historically theorized and empirically verified. We also discuss a range of mechanisms through which economic development drives contraceptive use independently from fertility decline. Finally, we assess the state and quality of evidence of these relationships and propose directions for future inquiry.
Non‐Specific Lipid Transfer Protein StLTP6 Promotes Virus Infection by Inhibiting Jasmonic Acid Signalling Pathway in Response to PVS TGB1
Authors: Shang Kaijie , Wang Chenchen , Wang Xipan , Wang Yubo , Xu Kaihao , Zhou Shumei , Liu Hongmei , Zhu Xiaoping , Zhu Changxiang
Published: November 2024

Plant viruses rely on host factors for successful infection. Non‐specific lipid transfer proteins (nsLTPs) play critical roles in plant−pathogen interactions; however, their functions and underlying molecular mechanisms in viral infections remain largely unknown. Jasmonic acid (JA) is a crucial regulatory hormone in the process of plant resistance to viral infection. In this study, we screened and verified that StLTP6, a previously identified pro‐viral factor, interacts with the silencing suppressor triple gene block1 (TGB1) of potato virus S (PVS). The PVS TGB1 induces the expression of StLTP6, and both co‐localize in the cytoplasm. Furthermore, StLTP6 interacts with allene oxide cyclase and inhibits its accumulation, thereby suppressing JA synthesis and attenuating RNA silencing antiviral resistance. In summary, we elucidated the molecular mechanism by which PVS TGB1 interacts with StLTP6 to facilitate PVS infection. These findings broaden our understanding of the biological roles of nsLTPs and provide a new antiviral target for potato research.
The Historical Presidency: Medical deception and the presidency in antebellum America
Authors: Appel Jacob M.
Published: November 2024

The illnesses of United States presidents have long been a subject of interest to both scholars and the American public. One particular area that has generated considerable study is the management of information surrounding such illnesses. An extensive literature has developed around efforts by the White House to conceal, downplay, or ignore presidential maladies. This literature has largely focused on the period from the Gilded Age to the present, accepting the widespread view that such efforts did not occur until the second half of the nineteenth century. This article examines four antebellum episodes in which the American public was not fully informed about the health of their leaders: James Madison's near‐fatal bout of “bilious fever” (1813), the final illnesses of William Henry Harrison (1841) and Zachary Taylor (1850), and Franklin Pierce's alcohol‐induced psychiatric decompensation after the death of his son (1853). Rather than a modern‐day phenomenon, this article argues that such deception is an ingrained and timeworn feature of the American political tradition.
A Lagrangian for Compressible Flow Focusing on Dissipation due to Thermal Conduction
Authors: Scholle M. , Ismail‐Sutton S. , Gaskell P. H.
Published: November 2024

With the aim of describing compressible viscous flows by means of a variational principle that takes into account heat conduction, a recently proposed Lagrangian is subjected to a detailed linear wave analysis that stems directly from the Lagrangian. The accompanying thermodynamic equation of state employed leads to a natural decomposition of the conduction term into three contributions, with the importance of each accessed through a detailed analysis employing a recently developed perturbation methodology giving rise to a favorable system of governing Jacobi equations. In addition to the model Lagrangian itself, three potential model scenarios—based on different combinations of the contributions forming the Lagrangian—are rigorously evaluated and appraised, regarding the occurrence, or otherwise, of dissipation recognizable by an attenuation of harmonic waves. Results reveal that two of the four models are suitable candidates, and suggest one in particular.
RhD‐negative red blood cells can be saved during liver transplantation in RhD‐negative patients due to low risk of alloimmunization against RhD
Authors: Juhl David , Braun Felix , Brockmann Christian , Musiolik Ingrid , Bunge‐Philipowski Tina , Luckner Kathrin , Görg Siegfried , Ziemann Malte
Published: November 2024

Background

Transfusion demand is high in liver transplantation (LT), and thus RhD‐positive (RhD+) red blood cell concentrates (RBCs) are sometimes given to RhD‐negative (RhD‐) patients. Due to immunosuppression, these patients rarely produce anti‐D. We investigated the rate of anti‐D formation in RhD‐ patients undergoing LT who were transfused with RhD+ RBCs as well as the number of transfused RhD‐ and RhD+ RBCs.

Study Design and Methods

RhD‐type and transfusion history of all patients undergoing LT between 2010 and 2023 were reviewed retrospectively. In RhD‐ patients, who received RhD+ RBCs, the results of antibody screening test (indirect antiglobulin test and with papain‐treated test cells) and direct antiglobulin test were evaluated.

Results

Five hundred and twenty‐seven patients underwent 576 LT. Eighty‐seven patients were RhD‐, of whom 42 were transfused with RhD+ RBCs. In 34 of them, an antibody screening test result was available more than two weeks after the last RhD+ RBCs transfusion. In two of them, a transient, weak anti‐D antibody was detectable, which disappeared in the further course. Overall, 1352 RBCs were transfused to the 87 RhD‐ patients, 543 of those were RhD+. Most RhD+ RBCs were provided to men and elder women.

Discussion

Transient weak anti‐D occurred in two RhD‐ male patients during LT after transfusion of RhD+ RBCs without evidence for a hemolytic transfusion reaction. To save stocks of RhD‐ RBCs, early transfusion of RhD+ RBCs to RhD‐ men and women beyond the childbearing age should be considered during LT.
Confirming the Third Law of Geography: Evidence in China’s Spring Festival Travel Rush
Authors: Liu Kai , Zhao Pengjun , Hai Xiaodong
Published: November 2024

The Third Law of Geography had been proposed by researchers for several years, yet empirical evidence within the field of human geography remained scarce. This study focused on the tidal characteristics of China's Spring Festival Travel Rush (Chunyun) across 365 cities in 2019, utilizing day-by-day time-series big data. It confirmed the presence and validity of the law, which posited that the more similar geographic configurations of two cities, the more similar the tidal features of human mobility between these two cities. Results showed that the logistic regression model had acceptable goodness of fit (0.421) and impacts of related indexes (city scale, labor supply, city level, traffic hub features, and dominant flow) had a statistically significant performance. Our research not only bolsters the use of data-driven policy decisions based on large-scale human mobility data but also offers a novel perspective to enhance the study of this law, serving as a pioneering effort to advance previous work.
Laurent expansions of meromorphic modular forms
Authors: Bogo Gabriele , Li Yingkun , Schwagenscheidt Markus
Published: November 2024

In this paper, we study the Laurent coefficients of meromorphic modular forms at complex multiplication points by giving two approaches of computing them. The first is a generalization of the method of Rodriguez‐Villegas and Zagier, which expresses the Laurent coefficients as constant terms of a family of polynomials obtained through recursion. The second applies to meromorphic modular forms that are regularized theta lifts, and expresses their Laurent coefficients in terms of Fourier coefficients of harmonic Maass forms.
Study on Mechanical Characteristics of High-Speed Impact Squeezing Process Under Two-Stage Propulsion Pattern
Authors: Guo Junting , Yu Yonggang , Zhang Xinwei
Published: November 2024

To deeply ascertain the transient extensive deformation process experienced by vehicle surface sealing band under a specified initial impact load within an innovative two-stage propulsion pattern, a sophisticated three-dimensional comprehensive dynamics model coupled with multitype propellant combustion theory and Arbitrary Lagrangian–Eulerian (ALE) algorithm is established, where VanLeer transport algorithm is applied to facilitate information exchange across computational grids. Following the validation of model rationality by comparing the results of 40 mm propulsion system dynamic impact experiment, numerical simulation is subsequently conducted to analyze the stress–strain characteristics of sealing band material and the mechanical mechanisms of interaction with the steel slope. The simulation results reveal that the dynamic interaction process spans a duration of 2.2 ms, during which the projectile motion transits through three distinct stages: deceleration, rebound, and acceleration. Throughout the deceleration stage, the material undergoes radial deformation and axial stress distribution as a result of the combined influence of extrusion force and friction force, with the peak surface stress reaching 400 MPa. As the projectile undergoes rebound, the front cone section of the material experiences shear fracture, leading to diverse shear conditions in the material surrounding the fractured elements. During the dynamic acceleration squeezing process, there is a progressive sequential failure of the material, propagating from the front to the back, with the proportion of mass experiencing failure reaching 14.8%. The conclusions obtained hold significant implications for the two-stage propulsion system.
Electrochemical Linked to Mechanical Simulation for an Assessment of State-of-Health of Thin-Flexible Li-Ion Batteries on Dynamic Flexing and Calendar Aging
Authors: Lall Pradeep , Jang Hyesoo
Published: November 2024

Flexible hybrid electronics featuring wearable electronics offer numerous advantages such as function integration, light-weighting, and flexibility. However, the dynamic flexing of the flexible power sources during usage, along with flex-to-install, presents challenges for their durability. While previous research has focused on thick block batteries, the effects of daily motion-induced stresses on the state of health (SOH) degradation of thin-flexible batteries, in conjunction with usage parameters, are not well understood. Factors such as storage duration, operating temperature, flexing frequency, interval, and flex radius may vary, making it impractical and expensive to measure the battery response in every condition. Therefore, electrochemical simulation methods are necessary to predict the SOH degradation of the battery under various environmental conditions, which can assess conditions not previously measured. However, the degradation of the flexible battery is not only due to electrochemical aging but also due to mechanical aging. While electrochemical simulation is well-known, the effect of mechanical factors on degradation is relatively unknown. In this regard, this research seeks to make multiphysics simulations of SOH deterioration during charging/discharging of a flexible battery under dynamic folding, twisting, and static folding using a calendar-aged battery at elevated temperatures. Additionally, the method, which is to link the mechanical simulation to electrochemical simulation, was studied, which may be helpful in further understanding of unknown effects required for future study. The paper thoroughly discusses the developed model's capability to predict SOH degradation caused by mechanical stress and calendar aging. It also explores how accurately the model can illustrate degradation trends under various environmental conditions. The detailed results and their significance are presented comprehensively, providing a clear understanding of the model's effectiveness within the context of the study.
Wideband Equivalent Circuit Modeling and Parameter Extraction Method for Through Via in Ceramic Package Substrate
Authors: Ren Pan , Wang Chulin , Liang Yaya , Zhao Xuan , Li Xiaojie , Pingan Du
Published: November 2024

There are numbers of through ceramic vias (TCVs) in ceramic package substrates for vertical interconnection of signal, and it would be very difficult, even impossible, to create the full-wave three-dimensional (3D) model of all TCVs during signal integrity (SI) analysis of a chip package. Thus, this paper presents a π-type equivalent circuit model for a signal TCV in steady of the full-wave 3D model. To improve model accuracy, the model takes into account the parasitic inductance and resistance induced by the skin effect of TCV at high frequencies, as well as the parallel plate effect between multilayer ground planes. A more accurate calculation method of via-plate capacitance is proposed based on the quasi-static method. According to the feature selective verification (FSV) method, the TCV S parameters calculated by the equivalent model and using the via-plate capacitance calculation method proposed in this study are in good consistency with those from high-frequency structure simulator (HFSS) full-wave 3D model in a wideband, and the solution time is reduced by 98.85%.
Unsteady Loss Mechanisms in Low-Pressure Turbines With Diverging End-Walls Studied Via High-Fidelity Simulation
Authors: Rosenzweig Marco , Kozul Melissa , Sandberg Richard D.
Published: November 2024

High-fidelity simulations are used to conduct controlled numerical experiments to investigate the effect of periodically incoming wakes on profile and three-dimensional loss mechanisms. The present work considers the MTU-T161 cascade with spanwise diverging end-walls, representative of a high-lift, low-pressure turbine blade. All simulations are carried out at engine-relevant conditions, with exit Reynolds number of 90,000 and exit Mach number of 0.6. Upstream moving bars are used to generate incoming wakes which impinge on the blade and potentially alter its aerodynamic performance. Unlike previous studies, the incoming wakes are subjected to an additional axial pressure gradient when convecting through the passage, due to the divergence of the spanwise end-walls. The evolving secondary vortex systems around the bars periodically disturb the freestream end-wall boundary layer facing the blade leading edge. This ultimately influences the end-wall related losses downstream of the blade and governs the overall aerodynamic performance of the blade. Following validation against available experimental data, a systematic variation of flow coefficient and reduced frequency extends the parametric space studied to encompass engine-realistic operating conditions. The high-fidelity simulations reveal the impact of incoming wakes on blade boundary layer losses and wake-induced losses both at the mid-span and within the end-wall regions. Furthermore, by decomposing the total loss generation, the data-rich results shed light on the underlying physical mechanisms driving unsteady losses when applied to phase- and time-averaged flow fields. Secondary losses incurred in the end-wall region show little sensitivity toward unsteadiness associated with incoming wakes and are rather prone to the turbulence levels in the passage. On the other hand, profile losses show high dependency on bar wakes in the absence of wake fogging. While profile losses can be minimized by certain combinations of flow coefficients and reduced frequencies, they remain the dominant source of unsteady loss generation.
Unsteady Flow Mechanism of Corner Separation Control Using Blade End Slots in a Highly Loaded Compressor Cascade
Authors: Liu Yangwei , Zhong Weibo , Tang Yumeng
Published: November 2024

Blade end slots have been proven to be an effective method to suppress corner separation, thereby improving the aerodynamic performance of the compressor. The unsteady effects of blade end slots affiliated with a highly loaded compressor cascade on corner separation control are investigated based on delayed detached eddy simulation under the Mach number of 0.59. The corner separation vortex structures between the datum blade and the end slotted blade are compared. The vortex topologies are markedly reorganized and suppressed by the blade end slots. Unsteady flow behaviors of separation vortex and the corresponding dynamic mechanisms are analyzed in both time and frequency domains. The interaction of the self-adaptive jet flow from the blade end slots to the corner separation flow results in smaller-scale vortices in the blade end region with a higher characteristic frequency. Consequently, the unsteady effects caused by corner separation vortices are significantly reduced in range and intensity through the enhancement of flow mixing and the rapid dissipation of corner separation vortices into larger-scale lower-frequency features. Furthermore, spatiotemporal features and dynamics of corner separation flow with blade end slot control are investigated using the enhanced dynamic mode decomposition method. Results show that the dominant unsteady flow behavior develops with better stability, the intermittency of low-frequency and large-scale behavior is reduced via the blade end slot control.
Bifurcation Analysis in Dynamical Systems Through Integration of Machine Learning and Dynamical Systems Theory
Authors: Mogharabin Nami , Ghadami Amin
Published: November 2024

Characterizing the nonlinear behavior of dynamical systems near the stability boundary is a critical step toward understanding, designing, and controlling systems prone to stability concerns. Traditional methods for bifurcation analysis in both experimental systems and large-dimensional models are often hindered either by the absence of an accurate model or by the analytical complexity involved. This paper presents a novel approach that combines the theoretical frameworks of nonlinear reduced-order modeling and stability analysis with advanced machine learning techniques to perform bifurcation analysis in dynamical systems. By focusing on a low-dimensional nonlinear invariant manifold, this work proposes a data-driven methodology that simplifies the process of bifurcation analysis in dynamical systems. The core of our approach lies in utilizing carefully designed neural networks to identify nonlinear transformations that map observation space into reduced manifold coordinates in its normal form where bifurcation analysis can be performed. The unique integration of analytical and data-driven approaches in the proposed method enables the learning of these transformations and the performance of bifurcation analysis with a limited number of trajectories. Therefore, this approach improves bifurcation analysis in model-less experimental systems and cost-sensitive high-fidelity simulations. The effectiveness of this approach is demonstrated across several examples.
Measurement of field emission array current distributions by metal-coated CMOS image sensors
Authors: Hausladen Mattias , Schels Andreas , Buchner Philipp , Bartl Mathias , Asgharzade Ali , Edler Simon , Wohlfartsstätter Dominik , Bachmann Michael , Schreiner Rupert
Published: November 2024

A CMOS image sensor is utilized to determine the time- and spatially resolved distribution of the total electron emission current of a silicon field emission array. The sensor measures electron emission without the need for phosphorus screens or scintillators as converters. However, in initial experiments, rather low field emission currents of several hundreds of nanoamperes per emitter already damaged the sensor surface, which altered the systems’ signal response over the measurement time. In consequence, we coated the CMOS sensor surface with a Cu layer for surface protection. In contrast to the original insulating surface, Cu is an excellent current- and heat-conductor, which avoids lens charging by providing a conductive path for incident electrons and has an improved heat dissipation capability. Measurements using a segmented field emission cathode with four individually addressable tips demonstrate a consistent correlation between the emission current and the sensor signal of the metal-coated image sensor. Furthermore, the characterization of a field emission array showed that single tip emission currents of up to 12 μA per tip are measurable without discernible damage effects of the sensor’s surface.
Geographic and Grade-Level Disparities in Student Access to School-Based Physical Education and Physical Activity Opportunities Across 25 US States
Authors: Killian Chad M. , Kern Ben D. , Wilson Wesley J. , van der Mars Hans
Published: November 2024

Background: Most US children and adolescents do not meet recommended daily physical activity (PA) guidelines. Determinants of PA are complex; however, access to opportunities precedes actual PA engagement. Schools are well positioned to support student PA through the provision of physical education (PE) and before, during, and after school PA opportunities through comprehensive (ie, expanded) school PA programming. Monitoring access to school PE and PA opportunities is an essential function of public health. However, there are limited comprehensive data across K–12 settings. Therefore, the purpose of this study was to evaluate students’ access to PE and expanded recreation time before, during, and after school PA opportunities in K–12 schools across 25 US states. Methods: The US Physical Education and Physical Activity Policy questionnaire was completed by 4845 K–12 PE teachers across 25 states, representing diverse geographical regions, with responses standardized across varying academic calendars. Descriptive statistics were used to illustrate access to PE and PA opportunities. Results: Access to PE and PA varied, with elementary schools generally providing more opportunities than middle and high schools. There was an overall misalignment with national PE and recess recommendations. Limited before and after school PA opportunities were also reported. Discussion: The relative dearth of access to PE and expanded PA opportunities currently available to students in relation to national guidelines shows a need for states to prioritize expanding access to PE and recreational PA to reduce disparities. To ensure more equitable student access, collaborative efforts among educators, policymakers, and stakeholders are essential.
Effects of Functional Movement Training on Batting Kinematics in Adolescent Baseball Players
Authors: Cheng He-Sin , Chiu Hung-Ta , Tsai Yi-Ju , Kuo Yi-Liang
Published: November 2024

Purpose: This study aimed to investigate the effects of 8-week functional movement training on batting kinematics and Functional Movement Screen (FMS) score in young baseball athletes with a composite FMS score of ≤14. Methods: A randomized controlled trial was conducted with 26 male junior high school baseball players (chronological age 13.52 y [0.66]; predicted age at peak height velocity 13.68 y [0.42]), randomly assigned to an experimental (performing functional movement training), or, a control group (performing routine training). Batting kinematics were assessed using a 3-dimensional motion analysis system, and FMS score was evaluated using the FMS test. Both outcomes were measured before and after training. Results: The experimental group significantly improved batting time and velocity and FMS score after training when compared with the control group. However, there were no significant changes in the other kinematic parameters between the experimental and control groups. Conclusion: Eight-week functional movement training demonstrated positive effects on batting performance and movement quality in adolescent baseball players with poor movement quality and core control. Further research is warranted to investigate the biomechanical mechanisms underlying these improvements.
Wohlfahrtiimonas chitiniclastica
: current insights and complementary review from Chinese cases
Authors: Yuan Qin , Peng Cheng , Sun Xin-Lin , Nie Zi-Chun , Zhang Yi-Wen , Miao Ying-Ye
Published: November 2024

Wohlfahrtiimonas chitiniclastica
is an emerging zoonotic pathogen associated with bacteremia, myiasis, and soft tissue infections. It is insufficiently identified and underestimated due to reasons, such as shortcomings of the traditional identification techniques and language barriers in local case reports from different regions. In this review, we summarize the currently available literature. In particular, we added previously overlooked cases from Chinese and other medical communities. The clinical characteristics, identification, and treatment of
W. chitiniclastica
are discussed. This work provides a complete review of the previous work including cases from human, animal, and other sources.
The group A
Streptococcus
pathogenicity island RD2: virulence role and barriers to conjugative transfer
Authors: Roshika Roshika , Baral Sushila , Jain Ira , Prabhu Ashna , Singh Ameya , Sumby Paul
Published: November 2024

Serotype M28 isolates of the bacterial pathogen the group A
Streptococcus
(GAS;
Streptococcus pyogenes
), but not isolates of other serotypes, have a nonrandom association with cases of puerperal sepsis, a life-threatening infection that can occur in women following childbirth. In prior studies, we established that RD2, a pathogenicity island present in all M28 GAS isolates but mostly absent from other serotypes, is a factor in the M28–puerperal sepsis association. Here, we identified a significant reduction in the RD2 conjugation frequency in inter-serotype conjugation assays relative to intra-serotype assays. As isolates of most GAS serotypes produce an antiphagocytic hyaluronic acid capsule, while M28 isolates do not, we tested whether the capsule served as a barrier to RD2 acquisition or maintenance. The data showed that capsule production had no impact on the RD2 conjugation frequency or on the ability of RD2 to enhance vaginal colonization by GAS, but did inhibit the ability of RD2 to enhance GAS adherence to vaginal epithelial cell lines. Further molecular explanations for the inter-serotype barrier to RD2 conjugative transfer were investigated, and a conserved, chromosomally encoded Type I restriction–modification system was identified as being key. We also identified that RD2 modifies the GAS transcriptome, including mRNAs encoding virulence factors with adherence and dissemination roles, following exposure to human plasma. Our data provide insights into factors that contribute to the restriction of the RD2 pathogenicity island to discrete subsets of the GAS population.