bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectral evolution of hot hybrid white dwarfs
Authors: Filiz Semih , Werner Klaus , Rauch Thomas , Reindl Nicole
Published: October 2024

Context. Hydrogen-rich white dwarfs (WDs) comprise the majority of the WD population, but are only rarely found at the very hot end of the WD cooling sequence. A small subgroup that exhibits both hydrogen and helium lines in their spectra, the so-called hybrid (or DAO) WDs, represents the majority of hydrogen-rich WDs at effective temperatures Teff ≈ 100 kK.

Aims. We aim to understand the spectral evolution of hot hybrid WDs. Although small in number, they represent an evolutionary phase for most (≈ 75%) WDs.

Methods. We conducted a nonlocal thermodynamic equilibrium (NLTE) analysis with fully metal line blanketed model atmospheres for the ultraviolet (UV) and optical spectra of a sample of 19 DA and 13 DAO WDs with Teff > 60 kK. The UV spectra allow us to precisely measure the temperature through model fits to metal lines in different ionization stages. This enables us to place the WDs accurately on the cooling sequence.

Results. In contrast to earlier studies that typically relied on temperature measurements made from hydrogen lines alone, all DAOs in our sample are clearly hotter than the DAs. DAOs transform into DAs when they cool to Teff ≈ 75–85 kK, depending on their mass. Along the cooling sequence, we witness a gradual decrease in the abundance of helium and the CNO elements in the DAOs due to gravitational settling. Simultaneously, iron and nickel abundances increase up to the transition region because radiative forces act more efficiently on them. This is followed by a steady decline. We discuss the implications of our results on atomic diffusion theory and on the role of weak radiation-driven winds in hot hydrogen-rich WDs.
Abundances of iron-peak elements in 58 bulge spheroid stars from APOGEE
Authors: Barbuy B. , Friaça A. C. S. , Ernandes H. , da Silva P. , Souza S. O. , Fernández-Trincado J. G. , Cunha K. , Smith V. V. , Masseron T. , Pérez-Villegas A. , Chiappini C. , Queiroz A. B. A. , Santiago B. X. , Beers T. C. , Anders F. , Schiavon R. P. , Valentini M. , Minniti D. , Geisler D. , Souto D. , Placco V. M. , Zoccali M. , Feltzing S. , Schultheis M. , Nitschelm C.
Published: October 2024

Context. Stars presently identified in the bulge spheroid are probably very old, and their abundances can be interpreted as due to the fast chemical enrichment of the early Galactic bulge. The abundances of the iron-peak elements are important tracers of nucleosynthesis processes, in particular oxygen burning, silicon burning, the weak s-process, and α-rich freeze-out.

Aims. The aim of this work is to derive the abundances of V, Cr, Mn, Co, Ni, and Cu in 58 bulge spheroid stars and to compare them with the results of a previous analysis of data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE).

Methods. We selected the best lines for V, Cr, Mn, Co, Ni, and Cu located within the H-band of the spectrum, identifying the most suitable ones for abundance determination, and discarding severe blends. Using the stellar physical parameters available for our sample from the DR17 release of the APOGEE project, we derived the individual abundances through spectrum synthesis. We then complemented these measurements with similar results from different bulge field and globular cluster stars, in order to define the trends of the individual elements and compare with the results of chemical-evolution models.

Results. We verify that the H-band has useful lines for the derivation of the elements V, Cr, Mn, Co, Ni, and Cu in moderately metalpoor stars. The abundances, plotted together with others from high-resolution spectroscopy of bulge stars, indicate that: V, Cr, and Ni vary in lockstep with Fe; Co tends to vary in lockstep with Fe, but could be showing a slight decrease with decreasing metallicity; and Mn and Cu decrease with decreasing metallicity. These behaviours are well reproduced by chemical-evolution models that adopt literature yields, except for Cu, which appears to drop faster than the models predict for [Fe/H]<−0.8. Finally, abundance indicators combined with kinematical and dynamical criteria appear to show that our 58 sample stars are likely to have originated in situ.
Environmental health risks (EHR) and E. coli concentration in refilled drinking water stations in Palembang (a cross-sectional study)
Authors: Astri Yanni Mery , Daniel D. , Nastiti Anindrya
Published: October 2024

This study aims to determine the relationship between environmental health risk (EHR) consisting of external area, building design and facilities, refilled station operators, equipment, and raw water, and the concentration of Escherichia coli (E. coli) in drinking water produced by the refilled drinking water station (RDWS). This cross-sectional study was conducted in 106 RDWS in Palembang City, Indonesia. The EHR checklist used a sanitation inspection and the concentration of E. coli obtained from water sample examinations using the membrane filter method. The average concentrations of E. coli (SD) in raw water and treated drinking water that is ready to distribute to the consumer, were 82 CFU/100 mL (121 CFU/100 mL) and 18 CFU/100 mL (45 CFU/100 mL), respectively. There was a significant difference in the average E. coli concentration between the raw water used and the treated drinking water (Z = −6.260; p < 0.001). There was a weak relationship between the outdoor area variable (r = −0.265) and equipment (r = −0.336) with the concentration of E. coli in the produced drinking water. Enforcement of regulations related to monitoring and reporting of drinking water quality needs to be carried out consistently to maintain the safety of refilled drinking water.
The university students’ knowledge and behavior towards food loss and waste in Sleman, Yogyakarta
Authors: Setyani Enrika R. , Mahiroh Hodimatum , Fitri Nabila N.A , Rahmatika Nanda T. , Rusprayunita Nurendah R.A , Desriani Ririn , Pribadi Ari P.
Published: October 2024

This study aims to learn about students’ knowledge, behavior, and food habits regarding domestic waste production. In late October 2023, a cross-sectional study using a purposive sampling was conducted among university students (n=85) in Sleman. An online questionnaire assessed their knowledge and behavior regarding domestic waste. Analysis data was using Stata/MP 17.0. The findings revealed that 30.6% of students potentially increased the domestic waste from leftover food. Among 51.8% of the students who cooked their dishes, 83.3% tended to produce vegetable waste, mainly from seeds, rind, and roots. Most students (87.1%) store their groceries at home/flat, and 56.8% often throw away the groceries if it has spoiled or reached their expiry date. Creating a shopping list was a viable solution in reducing domestic waste, as those who never (15.4%) and seldom (61.5%) made a shopping list are more likely to throw away their groceries if they exceed the expiry date. Although the students consistently finish their food, their knowledge, behavior, and food habits depict that they still could produce vast amounts of food waste. To effectively tackle and reduce the increasing domestic waste problem in Sleman, it is crucial to implement targeted food waste reduction initiatives.
Foodborne outbreak investigation in elementary school, Gunungkidul District, January 2024: A cohort retrospective study design
Authors: Oxy Handika Denis , Imam Utama Muhamad , Rizki Ananda Dwi , Maula Ahmad Watsiq , Ahmad Riris Andono , Hery Sukoco Sidig
Published: October 2024

On January 25, 2024, the Gunungkidul District Health Office was notified that three elementary school students fell ill after consuming snacks sold near the school. A team from Semanu II Health Center, in collaboration with the Gunungkidul District Health Office and Field Epidemiology Training Program Universitas Gadjah Mada residents, conducted an epidemiological investigation. This investigation aimed to identify the sources, risk factors, assess its extent, and provide suggestions for outbreak management. An active case-finding investigation was conducted, followed by a retrospective cohort study. Cases were individuals with one or more symptoms like nausea, vomiting, stomach pain, dizziness, chills, shortness of breath, and sore throat after consuming snacks sold near the school on January 25, 2024. In-depth interviews with structured questionnaires were used for data collection. Food handlers’ hygiene practices were observed, and food samples were tested at a health laboratory. A statistical analysis using chi-square and log-binomial regression was performed to measure the association in this study. 102 individuals were interviewed, 12 were considered cases. Most cases were in males (66.67%), aged 5 to 11 (66.67%), primarily third-grade students (50%), and a common symptom was nausea (100.00%). The epidemic curve had a common source, with incubation periods varying from 30 minutes to 14 hours. The median incubation period was 1 hour, while the average was 2 hours 23 minutes. The “Egg Macaroni” was associated with higher illness risk in this outbreak (aRR=14.5; 95% CI=1.7 − 21.1). Biological pathogens were detected in lab tests. Factors like poor hygiene practices, improper storage, reheating, and cross-contamination posed risks. The conclusion is that a foodborne outbreak at elementary school occurred in Gunungkidul District on January 25, 2024, and was caused by Bacillus cereus and mold/yeast. Implementation of healthy canteens in the school environment and increased education to improve food safety supervision is recommended.
Graphs whose vertices of degree at least 2 lie in a triangle
Authors: do Forte Vinicius L. , Lin Min Chih , Lucena Abilio , Maculan Nelson , Moyano Veronica A. , Szwarcfiter Jayme L.
Published: October 2024

A pendant vertex is one of degree one and an isolated vertex has degree zero. A neighborhood star-free (NSF for short) graph is one in which every vertex is contained in a triangle except pendant vertices and isolated vertices. This class has been considered before for several contexts. In the present paper, we study the complexity of the dominating induced matching (DIM) problem and the perfect edge domination (PED) problem for NSF graphs. We prove the corresponding decision problems are NP-Complete for several of its subclasses. As an added value of this study, we show three connected variants of planar positive 1in3SAT are also NP-Complete. Since these variants are more basic in complexity theory context than many graph problems, these results can be useful to prove that other problems are NP-Complete.
Lagerlogistik: Potenziale im Lager werden nicht ausgeschöpft
Authors: Otten Hubert
Published: October 2024

Das Lager ist in vielen Krankenhäusern wieder ein wichtiges Thema. Vergleicht man die Situation vor und nach Corona ist feststellbar, dass Lagerflächen vergrößert und Lagerreichweiten erhöht wurden. Dennoch führt das Lager in vielen Krankenhäusern noch ein Schattendasein.
Logistischer Masterplan Für Krankenhäuser: Strategische Betriebskonzepte für Neubauten und die Integration von Bestandsgebäuden
Authors: Raida Andrea , Moll Beate
Published: October 2024

Neubaumaßnahmen im Krankenhaus bieten die Chance, nicht nur neue betriebliche Konzepte zu realisieren, sondern damit auch grundlegend die Effizienz der Betriebsabläufe zu steigern. Um die Betriebskosten im Krankenhaus langfristig zu reduzieren, müssen die strategischen Grundkonzepte des Krankenhausbetriebs im weiteren Planungsverlauf zu logistischen Betriebskonzepten spezifiziert werden.
Einordnung: Krankenhauslogistik – selbst betreiben oder mit externem Partner?
Authors: Stachel Kerstin
Published: October 2024

Es gibt viele Gründe die Kliniklogistik an einen externen Dienstleister zu übergeben. Preisvorteile und Liefersicherheit sind dabei im Hauptfokus der Kliniken.
Reinigungsroboter: Marvin bringt Schwung in die Hygiene
Authors: Zenker Karin
Published: October 2024

An der Heinrich-Sommer-Klinik bringt neuerdings der Reinigungsroboter Marvin Effizienz und Erleichterung in den Arbeitsalltag. Der Einsatz macht nicht nur das Reinigungs- und Pflegepersonal glücklich, sondern auch das Management, denn er bringt erhebliche Einsparungen mit sich.
Distinct Role of GRK3 in Platelet Activation by Desensitization of G Protein-Coupled Receptors
Authors: Chaudhary Preeti K. , Kim Sanggu , Kunapuli Satya P. , Kim Soochong
Published: October 2024

Background Many platelet agonists mediate their cellular effects through G protein-coupled receptors (GPCRs) to induce platelet activation, and GPCR kinases (GRKs) have been demonstrated to have crucial roles in most GPCR functions in other cell types. Here, we investigated the functional role of GRK3 and the molecular basis for the regulation of GPCR desensitization by GRK3 in platelets.

Methods We used mice lacking GRK3 as well as β-arrestin2, which has been shown to be important in GPCR function in platelets.

Results Platelet aggregation and dense granule secretion induced by 2-MeSADP, U46619, thrombin, and AYPGKF were significantly potentiated in both GRK3 −/− and β-arrestin2 −/− platelets compared with wild-type (WT) platelets, whereas non-GPCR agonist collagen-induced platelet aggregation and secretion were not affected. We have previously shown that GRK6 is not involved in the regulation of Gq-coupled 5HT2A and Gz-coupled α2A adrenergic receptors. Interestingly, in contrast to GRK6, platelet aggregation induced by costimulation of serotonin and epinephrine, which activate 5-HT2A and α2A adrenergic receptors, respectively, was significantly potentiated in GRK3 −/− platelets, suggesting that GRK3 is involved in general GPCR regulation. In addition, platelet aggregation in response to the second challenge of adenosine diphosphate was restored in GRK3 −/− platelets, whereas restimulation of the agonist failed to induce aggregation in WT platelets, confirming that GRK3 contributes to general GPCR desensitization. Furthermore, 2-MeSADP- and AYPGKF-induced AKT and ERK phosphorylation were significantly potentiated in GRK3 −/− platelets. Finally, GRK3 −/− mice showed shorter tail bleeding times compared with WT, indicating that GRK3 −/− mice is more susceptible to hemostasis.

Conclusion GRK3 plays a crucial role in the regulation of platelet activation through general GPCR desensitization in platelets.
Enteroscopy-assisted ERCP in patients with surgically altered anatomy: Multicenter prospective registry (SAMISEN-B) using motorized spiral enteroscopy
Authors: Moreels Tom G , Aabakken Lars , Arvanitakis Marianna , Knabe Mate , Beyna Torsten
Published: October 2024

Background and study aims This was a prospective study of efficacy and safety of motorized spiral enteroscopy (MSE) to perform biliary endoscopic retrograde cholangiopancreatography (ERCP) in patients with surgically altered anatomy at five European centers.

Patients and methods Consecutive patients with biliary indications for enteroscopy-assisted ERCP were enrolled. Objectives were technical success, adverse event (AE) rate, and patient radiation exposure.

Results Eighty-nine patients were enrolled and one was excluded for a pancreatic indication. All participants had variations of Billroth II reconstruction (29.5%) or Roux-en-Y reconstruction (70.5%), either with naive papilla (39%) or hepaticojejunostomy (61%). Main indications were anastomotic stricture treatment and/or biliary stone removal. Enteroscopy to reach the bile duct was possible in 65 of 88 patients (74%), bile duct cannulation in 54 of 88 (61%), and therapeutic ERCP was technically successful in 48 of 88 (54%). In Billroth II variations, technical success was achieved in 13 of 26 patients (50%) compared with 35 of 62 (57%, P = 0.5792 Chi square) in Roux-en-Y reconstructions (including bariatric gastric bypass). ERCP with intact papilla was successful in 17 of 34 patients (50%) compared with 31 of 54 (57%, P = 0.4968 Chi square) in hepaticojejunostomy. The study was prematurely terminated July 2023 because MSE was withdrawn by the manufacturer for safety issues. Overall, in 12 of 88 patients (14%), AEs were recorded and six (7%) were considered serious. Only one serious AE was attributable to MSE enteroscopy: perforation of the proximal esophagus during enteroscope insertion.

Conclusions This prospective multicenter study was prematurely discontinued due to withdrawal of the MSE by the manufacturer because of safety issues. Technical success of MSE-assisted biliary ERCP in different types of surgically altered anatomy was 54%, which was lower than anticipated. There was one esophageal perforation attributable to use of MSE. (clinicaltrials.gov: NCT05129449)
Advances in Small-Molecule C-KIT/PDGFRα Inhibitors for the Treatment of Gastrointestinal Stromal Tumors
Authors: Zheng Xuan , Liang Hong , Zhou Yang , Lu Xiaoyun
Published: October 2024

Stem cell factor receptor (C-KIT) or platelet-derived growth factor receptor α (PDGFRα) gene mutations have been identified as oncogenic drivers for most gastrointestinal stromal tumors (GISTs). Thus, small-molecule inhibitors of C-KIT or PDGFRα have emerged as effective treatments for GISTs. Although the currently approved first- to fourth-line drugs are initially effective against GISTs, the inevitable development of drug resistance remains an unmet challenge. To address secondary mutations leading to drug resistance, several novel selective C-KIT/PDGFRα small-molecule inhibitors have been developed and clinically studied. This review summarizes the pathogenesis, treatment, and drug resistance mechanisms of GISTs and briefly describes current challenges and future efforts for GIST treatment using small-molecule kinase inhibitors.
Immune-Mediated Neuropathies: Top 10 Clinical Pearls
Authors: Monohan Elizabeth M. , Brannagan Thomas H.
Published: October 2024

Immune-mediated neuropathies encompass a range of neurological disorders, including chronic inflammatory demyelinating polyradiculoneuropathy, Guillain–Barré syndrome, multifocal motor neuropathy, autoimmune autonomic neuropathies, and paranodal nodopathies. Recognizing clinical patterns is key to narrowing the broad range of differential diagnoses in immune-mediated neuropathies. Electrodiagnostic testing is a useful tool to support the diagnosis of immune-mediated neuropathies. Our understanding of autoimmune demyelinating neuropathies is rapidly advancing, particularly with the discovery of nodal and paranodal antibodies. Recent advances in neuropathy treatment include the utilization of neonatal Fc receptors to reduce antibody recycling, and the development of complement inhibitors to reduce inflammatory damage, offering promising new therapeutic avenues. Timely identification of immune-mediated neuropathies is imperative as delay in diagnosis and treatment may lead to irreversible disability.
Venous Thromboembolism after Hospital Discharge: Temporal Trends in Baseline Characteristics, Prevention, Treatment, and 90-day Outcomes
Authors: Brenner Benjamin , Tzoran Inna , Bikdeli Behnood , Valle Reina , Poenou Géraldine , Tirado-Miranda Raimundo , Pesce María L. , Pagán-Escribano Javier , Giorgi-Pierfranceschi Matteo , Monreal Manuel ,   the RIETE Investigators
Published: October 2024

Venous thromboembolism (VTE) after hospital discharge poses a serious health risk. Assessments of patient characteristics, prophylaxis, treatment, outcomes, and over time changes lack consistency. Data on 16,901 hospitalized patients in the Registro Informatizado Enfermedad TromboEmbolica registry (2003–2022) were analyzed to evaluate trends in baseline characteristics, prophylaxis, treatments, and 90-day outcomes among medical (6,218) and surgical (10,683) patient cohorts. Multivariable logistic regression was used to assess the risks of the composite of fatal pulmonary embolism (PE) or recurrent VTE and major bleeding. The proportion of patients who presented with PE increased among medical (from 54 to 72%) and surgical patients (from 55 to 58%). Prophylaxis use increased in medical patients (from 53 to 71%), while decreasing in surgical patients (from 67 to 58%). Notably, the 90-day composite of fatal PE or recurrent VTE decreased in medical (from 3.9 to 1.8%) and surgical patients (from 2.9 to 1.2%; p < 0.001 for both). Conversely, major bleeding increased (3.1 to 4.5%) in medical patients (p = 0.008), with no change in surgical patients (from 2.5 to 2.4%). Risk-adjusted analysis showed a yearly decrease in the risk for the composite outcome (subhazard ratio [sHR]: 0.95; 95% confidence interval [CI]: 0.93–0.98) in medical and surgical patients and an increase in the risk for major bleeding in medical patients only (sHR: 1.04; 95% CI: 1.01–1.07). Results were consistent after excluding coronavirus disease 2019 patients. Over 20 years, the composite of fatal PE or recurrent VTE within 90 days had significantly decreased in VTE patients after hospitalization for medical or surgical care. Medical patients, however, exhibited an increase in major bleeding.
Switching location—shifting mindset? The attitude towards female employment of East–West migrants in Germany
Authors: Kriechel Lisa , Muehlan Holger , Brähler Elmar , Beutel Manfred E.
Published: October 2024

The strong migration of former East German residents to the western part of Germany opens a unique way to study the impact of migration modifying gender-related attitudes towards division of labor. While in West Germany more traditional gender attitudes have been prevailing for decades, the East pursued more progressive attitudes regarding the home and labor domain. However, attitudes of East-to-West migrants are mostly unknown. Thus, this article aims at providing a first analysis regarding differing attitudes between domestic migrants and non-movers. Data from the German General Social Surveys (GGSS/ALLBUS) from 1992, 2004, and 2016, including 2428, 2099, and 1486 participants, respectively, were used. Group differences between permanent residents from West Germany (West–West) and from East Germany (East–East) as well as East-to-West migrants were estimated. Pooled regressions were conducted to predict the attitudes towards female employment. East–West migrants’ respective attitudes differed from both of the other groups. However, they were more similar to the more traditional West–West group than the more progressive East–East group. Furthermore, East–West migrants who had lived longer in the West exhibited more traditional attitudes than those who had lived there <10 years. Further, the diversity of East-to-West migrants was acknowledged by observing the year of migration (before 1961, 1961–1989, after 1989) which showed that those who migrated before the erection of the Berlin Wall were more traditional. The finding that East–West migrants’ attitudes were more similar to their place of residence, while the duration of residence was positively associated with the traditional attitude towards female employment prevalent in the West, gives impetus to further research attitudes of domestic migrants. Future research should test whether a selection effect or assimilation cause East–West migrants’ attitudes to resemble their society of residence.
Consistent effects of science and scientist characteristics on public trust across political regimes
Authors: Younger-Khan Sukayna , Weidmann Nils B. , Oswald Lisa
Published: October 2024

Recent years have seen an increased research interest in the determinants of public trust in science. While some argue that democracy should be the political regime most conducive to science, recent debates about salient scientific findings revealed considerable cracks in the public perception of science. We argue that existing cross-national work on trust in science is incomplete because it uses an aggregate concept of “science”. People in different political environments likely have different conceptions of what science is, which can have consequences for perceptions and trust. To remedy this shortcoming, we present results from a preregistered survey experiment in ten countries (N = 8441), which covers a broad spectrum of political regimes and tests how science and scientists’ characteristics influence public trust. We find that, against expectations, female scientists and scientists engaging in public activism are both perceived as more trustworthy. High-impact research is trusted more than low-impact research, and it does not matter whether a scientist is a co-national. Overall, our experiment reveals few differences across political regimes. Additional survey results show that respondents’ education and exposure to science have similar relationships with trust across autocratic and democratic countries. A striking difference we find is that while political orientation has little impact in autocratic countries, it is strongly related to trust across democracies as perceptions of science become increasingly politicized.
Stigma, support, and messaging for people recently diagnosed with HIV: a qualitative study
Authors: Healey Loretta M. , Markham Shirin R. , Templeton David J. , Rabie Lionel , Smith Anthony K. J.
Published: October 2024

Background Despite advances in antiretroviral treatment and the message of undetectable equals untransmittable (U=U), there remain challenges related to stigma and quality of life for people living with HIV. This study aimed to understand the experiences of people recently diagnosed with HIV at a clinical service, to guide insights into how to improve care and support in the contemporary treatment era. Methods This qualitative study involved semi-structured interviews with individuals diagnosed with HIV between 2016 and 2021 at RPA Sexual Health service (a sexual health clinic in Sydney, Australia), or who were referred to the clinic directly after diagnosis. Participants were recruited through a short survey questionnaire between May 2022 and May 2023, and interviews were transcribed and analysed thematically. Results Fourteen participants were interviewed for the study, eight of whom were born outside of Australian or Aotearoa New Zealand. We found that diagnosis was still a shocking event requiring careful support; that there was ongoing stigma, shame, and reduced sexual confidence following diagnosis; and that beyond initial diagnosis, some people would benefit from ongoing support and education about key concepts regarding HIV treatment. Conclusion Our study suggests that HIV diagnosis remains disruptive, and sexual stigma is a key issue negatively impacting quality of life. Health providers can mitigate these issues by supporting the ongoing psychosocial needs of people with HIV in the early period of adjusting to HIV diagnosis, and referring to peer-based and other services. Initiating conversations about sex and dating and checking understandings of key health messages over time may promote improved care.
Playing one’s part within a medial procedure
Authors: Albert Georg
Published: October 2024

The study at hand is part of a research project dedicated to the topic management in a political
talk show. Here, the focus is on the talk show host’s activities resulting from her role-specific tasks within the
show. The detailed analysis is dedicated to her presentations of pre-produced film clips as part of the show. Data
samples are taken from a corpus of 19 editions of the German Anne Will show. The video samples and
corresponding transcripts have been closely analysed with special regard to sequential organisation and the
concurrence of verbal and non-verbal expressions. The observed interactions reflect their medial context, which,
reciprocally, is also the result of the participants’ practices: It is only within the medial context of a political
TV discussion that film clips need to be introduced during the ongoing conversation and, at the same time, can be
utilized to moderate between distinct participant groups.
Active learning-based automated construction of Hamiltonian for structural phase transitions: a case study on BaTiO3
Authors: Dai Mian , Zhang Yixuan , Fortunato Nuno , Chen Peng , Zhang Hongbin
Published: October 2024

The effective Hamiltonians have been widely applied to simulate the phase transitions in polarizable materials, with coefficients obtained by fitting to accurate first-principles calculations. However, it is tedious to generate distorted structures with symmetry constraints, in particular when high-ordered terms are considered. In this work, we implement and apply a Bayesian optimization-based approach to sample potential energy surfaces, automating the effective Hamiltonian construction by selecting distorted structures via active learning. Taking BaTiO3 (BTO) as an example, we demonstrate that the effective Hamiltonian can be obtained using fewer than 30 distorted structures. Follow-up Monte Carlo simulations can reproduce the structural phase transition temperatures of BTO, comparable to experimental values with an error

<

10%. Our approach can be straightforwardly applied on other polarizable materials and paves the way for quantitative atomistic modelling of diffusionless phase transitions.
An improved prediction method for BDS-3 SISA parameters and the preliminary performance evaluation
Authors: Hu Guo , Cao Yueling , Chen Lei , Gao Weiguang , Chen Jianbing , Li Haojun , Zhou Shanshi
Published: October 2024

The ephemeris accuracy parameters broadcast in the ephemeris messages are commonly utilized as an alarm threshold for the signal-in-space ranging errors (SISRE) of the Global Navigation Satellite System (GNSS). Accurately predicting the orbit and clock errors of broadcast ephemeris, and converting the prediction errors into broadcast ephemeris accuracy parameters using a robust model, is important for the integrity service of GNSS. The BeiDou Navigation Satellite System (BDS-3) broadcasts four ephemeris accuracy parameters, namely

SIS

A

oe

,

SIS

A

ocb

,

SIS

A

oc1

, and

SIS

A

oc2

, to represent the standard deviations of the satellite orbit and clock prediction errors in the broadcast ephemeris. The probability that the broadcast ephemeris SISRE exceeds 4.42 times the signal-in-space accuracy (SISA) without triggering an alarm in time is expected to be less than 1 × 10−5. In addition to accurately enveloping the broadcast ephemeris SISRE, SISA should also reduce the over-envelopment margin over SISRE to accurately express the system service accuracy. Thus, an accurate prediction of orbit and clock errors in the broadcast ephemeris is crucial for calculating the SISA. An orbit and clock error prediction method based on the Long Short-Term Memory (LSTM) neural network is proposed in this study. This method uses historical satellite orbit and clock errors, derived from the difference between precise and broadcast ephemeris, to train an LSTM neural network. The trained LSTM model is then used to predict the orbit and clock errors for the next 24 h. The predicted errors are used to calculate the corresponding SISA for the broadcast ephemeris. The results indicate that the 24 h accuracies of the predicted orbit and clock errors are less than 0.06 m and 0.25 m, respectively. The calculated SISA can completely envelop the actual broadcast ephemeris SISRE, achieving 100% coverage while also decreasing the over-envelopment margin by 80%. Furthermore, the horizontal protection level and vertical protection level calculated using the corresponding SISA are reduced by approximately 14%, meeting the integrity requirements set by the International Civil Aviation Organization for Approach with Vertical Guidance I. The proposed method enhances the timeliness of SISA parameter calculation and the integrity and availability of the BDS-3 service, serving as a crucial reference value for safety critical applications such as civil aviation services.
Fault identification of hydropower unit based on time–frequency feature map of vibration signals and Convrbm-ResNet
Authors: Chen Tingxi , Chen Jinbao , Zou Yidong , Liu Dong , Hu Wenqing , Zheng Yang , Xiao Zhihuai
Published: October 2024

To address the significant impact of the non-stationarity and nonlinearity of vibration signals on the accuracy of fault identification in hydropower units, a method for condition identification based on time–frequency characteristics of vibration signals and Convolutional Restricted Boltzmann Machines-Residual Network (ConvRBM-ResNet ) is proposed. The vibration signals are first decomposed by adopting Complementary Comprehensive Empirical Modal Decomposition to further obtain Intrinsic Mode Functions (IMFs) at various frequencies. Then, by combining correlation analysis, the more sensitive IMF components are extracted. Furthermore, the obtained effective IMF components are converted into time–frequency feature maps, which are consequently adopted as inputs to pre-train the ConvRBM model to simplify feature representation. Finally, using the fault category as the output, a fault identification model for hydropower units is obtained by training ConvRBM-ResNet. The proposed fault identification model is validated with actual operation data of a hydropower station. The results indicate that the proposed fault identification model can accurately identify the operating status of the hydropower unit, achieving an accuracy of 98.88%, which is a 4% improvement over the non-improved method. The time cost is reasonable, and the model demonstrates strong robustness.
Growth of zinc oxide nanowires by a hot water deposition method
Authors: Saadi Nawzat S , Hassan Laylan B , Sayem S M , More Karren L , Karabacak Tansel
Published: October 2024

Recently, various methods have been developed for synthesizing zinc oxide (ZnO) nanostructures, including physical and chemical vapor deposition, as well as wet chemistry. These common methods require either high temperature, high vacuum, or toxic chemicals. In this study, we report the growth of zinc oxide ZnO nanowires by a new hot water deposition (HWD) method on various types of substrates, including copper plates, foams, and meshes, as well as on indium tin oxide (ITO)-coated glasses (ITO/glass). HWD is derived from the hot water treatment (HWT) method, which involves immersing piece(s) of metal and substrate(s) in hot deionized water and does not require any additives or catalysts. Metal acts as the source of metal oxide molecules that migrate in water and deposit on the substrate surface to form metal oxide nanostructures (MONSTRs). The morphological and crystallographic analyses of the source-metals and substrates revealed the presence of uniformly crystalline ZnO nanorods after the HWD. In addition, the growth mechanism of ZnO nanowires using HWD is discussed. This process is simple, inexpensive, low temperature, scalable, and eco-friendly. Moreover, HWD can be used to deposit a large variety of MONSTRs on almost any type of substrate material or geometry.
A generalized Biot–Savart law and its application to the active scalar equations
Authors: Chen Qionglei , Hao Xiaonan , Wang Chao
Published: October 2024

In this paper, we study a generalized Biot–Savart law for suitable velocity that possibly diverges at infinity, and then show its application to the 2D general incompressible inviscid fluids. We first prove the generalized Biot–Savart law for the active scalar equations in a discrete rotational symmetry framework, which allows the velocity grow almost linearly at infinity. Based on this, we further obtain a unique global symmetric solution to Euler equation under the Yudovich type regularity. Additionally, we investigate the local well-posedness for the Boussnesq equation, SQG equation, and especially for the IPM equation which enjoys particular symmetric property in our setting. The proof mainly relies on the Fourier model analysis and some refined estimates to the singular integral operator.
Assessing suitability and stability of materials for a head and neck anthropomorphic multimodality (MRI/CT) phantoms for radiotherapy
Authors: Alzahrani Meshal , Broadbent David A , Teh Irvin , Al-Qaisieh Bashar , Speight Richard
Published: October 2024

Objective: This study aims to identify and evaluate suitable and stable materials for developing a head and neck anthropomorphic multimodality phantom for radiotherapy purposes. These materials must mimic human head and neck tissues in both computed tomography (CT) and magnetic resonance imaging (MRI) and maintain stable imaging properties over time and after radiation exposure, including the high levels associated with linear accelerator (linac) use. Approach: Various materials were assessed by measuring their CT numbers and T1 and T2 relaxation times. These measurements were compared to literature values to determine how closely the properties of the candidate materials resemble those of human tissues in the head and neck region. The stability of these properties was evaluated monthly over a year and after radiation exposure to doses up to 1000 Gy. Statistical analyzes were conducted to identify any significant changes over time and after radiation exposure. Main results: 10% and 12.6% Polyvinyl alcohol cryogel (PVA-c) both exhibited T1 and T2 relaxation times and CT numbers within the range appropriate for brain grey matter. 14.3% PVA-c and some plastic-based materials matched the MRI properties of brain white matter, with CT numbers close to the clinical range. Additionally, some plastic-based materials showed T1 and T2 relaxation times consistent with MRI properties of fat, although their CT numbers were not suitable. Over time and after irradiation, 10% PVA-c maintained consistent properties for brain grey matter. 12.6% PVA-c’s T1 relaxation time decreased beyond the range after the first month. Significance: This study identified 10% PVA-c as a substitute for brain grey matter, demonstrating stable imaging properties over a year and after radiation exposure up to 1000 Gy. However, the results highlight a need for further research to find additional materials to accurately simulate a wider range of human tissues.
Investigation of swelling mechanisms in self-adherent microneedles
Authors: Tarpey Ruth , Islam Shahrin , Bernardo Bruno , Singh Manisha , Lee Eunjee A , Karp Jeffrey M , Lee Yuhan , Roche Ellen T , Ronan William
Published: October 2024

Swellable microneedles (MNs) expand to mechanically interlock with wet biological tissue, offering improved adhesion and enhanced drug delivery over non-swellable counterparts. This study numerically evaluates how the material and geometric parameters of swellable MN arrays influence shape change. Using finite element simulation, MNs were subjected to unconstrained swelling, approximated via a thermal-strain analogy. Optimal MN design must support mechanical interlocking to prevent dislodgement. We observed that wet in vivo environments induce unwanted swelling-mediated curvature, hindering contact and interlocking. We quantified this bending and calibrated gel material swellability using experimental data. To counteract curling, we introduced a design approach to shift the direction of the unwanted curling and improve MN array conformability.
Performance optimization of MA0.5FA0.5PbI3/CsPbI3 based hybrid perovskite solar cell emphasizing on double absorber layer
Authors: Kaur Jaspinder , Garg Sidharth , Basu Rikmantra , Sharma Ajay Kumar , Pandey Rahul , Madan Jaya , Saddullah Md
Published: October 2024

The utilization of cesium-based lead halide (CsPbI3) PSC has considerable potential in the photovoltaic industry due to their high efficiency, underpinned by features such as a high absorption coefficient, thermal stability, and commendable efficiency. Nevertheless, the bandgap of CsPbI3, standing at 1.7 eV, poses a challenge as it is relatively high for a single-junction device. To overcome this limitation, we introduced a dual absorber layer structure by interleaving CsPbI3 with a lead-based hybrid perovskite material, denoted as MA0.5FA0.5PbI3. This investigation focused on the MA0.5FA0.5PbI3/CsPbI3 hetero-junction structure to ascertain the maximum possible efficiency. Therefore, this study proposed a PSC with the configuration of Ag/MoO3/MA0.5FA0.5PbI3/CsPbI3/IGZO/Au. In this setup, MoO3 (Molybdenum Trioxide) is used as the HTL and IGZO (Indium Gallium Zinc Oxide) as the ETL. Silver (Ag) serves as the back contact and gold (Au) is the front contact. This device demonstrated remarkable characteristics with Voc = 1.307 V, Jsc = 22.71 mA cm−2, FF = 86.58%, and η = 26.21%, showcasing a substantial improvement compared to previously reported CsPbI3-based homojunction PSCs. Furthermore, this study delved into the effects of absorber doping, absorber material thickness, bulk defect, and interfacial defects on solar cell parameters to obtain high-performance solar cells.
Comparative analysis of machine learning techniques in predicting dielectric behavior of ternary chalcogenide thin films
Authors: Mohamed R A , Atyia H E
Published: October 2024

The current research introduces a comparative analysis of the dielectric behavior exhibited by ternary chalcogenide thin films, including both experimental data and machine learning techniques. The study of temperature and frequency dependencies of dielectric parameters is crucial for assessing material losses, particularly focusing on the low-frequency range where dielectric dispersion occurs. The experimental results on the frequency (100–1000000 Hz)and the temperature(303–393 K) influences on the dielectric (constant (

ε

1

) and loss (

ε

2

)) of

A

s

4

G

e

24

T

e

72

composition in thin film form have been discussed. Results demonstrate that ε
1 exhibits an increasing trend with temperature, attributed to heightened orientation polarization as dipoles gain mobility with elevated thermal energy. Conversely, ε
1 declines with rising frequency, reflecting diverse different polarization mechanisms. Understanding these behaviors is important for material characterization and applications in fields like electronics and solar cells. A comparative analysis of the dielectric behavior exhibited by ternary chalcogenide thin films, including both experimental data and machine learning techniques. Through the experimental approach, the dielectric properties of the films are investigated. Additionally, the study employs a range of machine learning algorithms, including Artificial Neural Networks (ANN), Adaptive Neuro-Fuzzy Inference Systems (ANFIS), Genetic Programming (GP), hybrid techniques ANFIS-GA, and ANFIS-PSO, to model and predict the dielectric behavior with remarkable accuracy. The paper presents a comparison between the performance of the proposed machine learning models, highlighting their strengths and limitations in capturing the complex dielectric phenomena observed in the ternary chalcogenide thin films. This comparative study not only provides valuable insights into the dielectric properties of these materials but also demonstrates the efficacy of machine learning in understanding and predicting their behavior, paving the way for further advancements in materials science and device development.
Prediction of crystal structures and superconductivity of actinium borides at high pressures
Authors: Qin Yanqing , Song Jiexi , Chen Xinyu , Shi Diwei , Yang Fuqiang , Cao Chongde
Published: October 2024

To investigate potential compounds that may emerge in actinium borides at high-pressure conditions. In this work, we carried out systematic crystal structure search procedure on the Ac-B compounds from 0 to 300 GPa conditions based on evolutionary algorithms and density functional theory (DFT). We discovered a stable phase Pm_3m-AcB6 at 0 GPa with common structure of hexaboride and three phases R_3m-AcB, Cmmm-Ac2B11, and R_3m-AcB8 at higher pressures in the Ac-B system. Our results show that AcB8 and Ac2B11 are superconducting, especially Ac2B11, which exhibits a Vickers hardness of approximately 31 GPa and a superconducting transition temperature T

c
of 14.4 K at 0 GPa. The mechanical and dynamical stability of these Ac-B phases have been verified through the application of Born criteria and phonon calculations. Furthermore, their density of states (DOS) indicates that they all exhibit metallic properties. The mechanical properties of AcB6 are comparable to those of LaB6 with the same structure, whereas AcB demonstrates the poorest mechanical performance and a low bonding tendency, manifested by its distinct tendency towards brittleness, as evident from its Pugh’s ratio. The structure of Ac2B11 resembles a middle phase evolving from the hexaboride AcB6 towards a class of pentaboride structures, characterized by the formation of a B22 cage structure resulting from further boron enrichment based on the B20 cage, or derived from the partial dimerization of the B24 cage found in hexaborides. We believe that this configuration may hold significant potential as a parent matrix for the design of interesting ultra-hard materials with relatively high superconducting transition temperatures.
Structural modifications of BiOBr nanoplates by electron beam irradiation
Authors: Kumar Sen Sapan , Hossain Md Shahadat , Alam M S , Manir M S , Dutta Supria
Published: October 2024

In this study, BiOBr nanoplates are synthesized through the hydrothermal method, then samples have been irradiated by an electron beam of 10 MeV energy to deliver doses of 100 kGy and 500 kGy. XRD and Raman investigations corroborated the presence of a pure phase in all nanoplate samples. The sharp and narrow peaks in XRD indicate well crystalline in nature of the samples, which decreases with increasing the electron dose as confirmed by the decay in peak intensity. Conversely, the peak position shifts at lower angle with increasing the electron dose. Structural factors including lattice parameter, dislocation density, cell volume, microstrain, as well as stacking fault have been found to change due to electron beam irradiation. We employed the Debey-Scherrer formula (D-S), Size Strain Plot method (SSP), and Halder Wagner (H-W) methods to determine the crystal size and strain of purified and irradiated BiOBr nanoplates. It has been found that the size of the crystallites increases nonlinearly as the irradiation dose increases. All three of the aforementioned calculation methods have observed this trend. Strain and dislocation density exhibited the opposite trend of crystallite size, as they decreased as the irradiation dose increased. The dislocation density, strain, and crystallite size values are nearly identical for the SSP and H-W procedures, while the D-S method exhibits values with deviation. The tetragonal structure and the Raman active mode, which we have identified as closely resembling those in other literature of this composition, are discussed in the respective section. Because of their intriguing phase strength, the synthesized nanoplates may be suitable for the degradation of organic pollutants and the separation of water through photo-electrocatalysis.
Exploring complex dynamics in a Stackelberg Cournot duopoly game model
Authors: Ahmed Rizwan , Khalid Asma , Karam Sadaf
Published: October 2024

In this study, we investigate the dynamics of a Cournot duopoly game model with bounded rational players, incorporating a leader-follower mechanism where the first player acts as a leader and the second as a follower, aware of the leader’s production. We examine the existence and stability of all fixed points in the model and use center manifold and bifurcation theory to analyze the occurrence and direction of period-doubling and Neimark-Sacker bifurcations at the positive fixed point. To control bifurcation and chaos, feedback control and hybrid control methods are applied. Numerical examples are provided to confirm our theoretical results and reveal the model’s complex dynamics. Our results highlight the critical role of the leader’s strategic decisions, particularly the adjustment speed parameter v
1, in driving the system from stability to chaos, affecting both firms and leading to significant shifts in market dynamics.