bluuebunny/crossref_metadata_2025 huggingface dataset:
Paradoxes in work-related learning—and how they are perceived by practitioners
Authors: Paulsen Hilko , Kortsch Timo , Decius Julian
Published: August 2024

This article in the journal “Gruppe. Interaktion. Organisation (GIO)” theoretically and empirically examines potential paradoxes in work-related learning. Organizations are full of paradoxical situations that also affect work-related learning. Based on three forms of work-related learning (i.e., formal, informal, and self-regulated learning) and three learning-relevant dimensions of organizational goal conflicts (i.e., stability vs. change, exploration vs. exploitation, and short-term vs. long-term), nine work-related learning tensions are described that can lead to paradoxical situations. Using survey data of 113 experts from the field, these tensions were evaluated according to their frequency in everyday organizational life and their perceived contradictory nature. The findings show that there are many frequently occurring but less contradictory tensions and some very contradictory but rarely occurring tensions. Implications of the results are discussed.
Die Dreidimensionalität der Organisationsparadoxie – Prozessstudie eines Krankenhauses im Umgang mit der COVID-19 Pandemie
Authors: Tuckermann Harald
Published: August 2024

Während der COVID-19 Pandemie mussten Krankenhäuser und ihre Mitarbeitenden mit vielfältigen Paradoxien umgehen, die als permanente Widersprüche unterschiedlicher Erwartungen sichtbar wurden. Die systemtheoretisch informierte Analyse der Daten einer longitudinalen Prozessstudie eines Krankenhauses zum Umgang mit der Pandemie fokussiert auf das spannungsreiche Verhältnis zur Erwartung, sowohl COVID-19 als auch möglichst alle anderen Patienten zu behandeln, das die Paradoxie auf Ebene der Organisation als Spannungsfeld zwischen Einheiten illustriert. Die Analyse zeigt auf, dass diese Paradoxie drei zu berücksichtigende Dimensionen aufweist. Sachlich stehen unterschiedliche Alternativen zur Auswahl. Sozial gilt es, zwischen zentralen Vorgaben und dezentraler Akzeptanz von Entscheidungen zu balancieren. Zeitlich geht es um die Berücksichtigung der gegenwärtigen Situation und der künftigen Entwicklung. Diese Dreidimensionalität charakterisiert die praktische Herausforderung im Umgang mit einer Extremsituation wie der Pandemie, deren Beginn, Intensität, Dynamik und Dauer nicht prognostizierbar sind. Neben dieser praktisch relevanten Rekonstruktion liegt der theoretische Beitrag mit Blick auf die englischsprachige Literatur zu organisationalen Paradoxien darin, den dortigen Fokus auf eine Dimension auszudehnen und somit den Erklärungsraum der Forschung zu erweitern.
Potential Development Ability of Residual Zoites, a Second-Generation Meront, Inducing Long-Term Infection by the Mouse Eimerian Parasite, Eimeria krijgsmanni
Authors: Mizuno Masanobu , Kiyotake Satoru , Matsubayashi Makoto , Kaneko Takane , Hatai Hitoshi , Fujimoto Yoshikazu , Ijiri Moe , Kawaguchi Hiroaki , Matsui Toshihiro , Matsuo Tomohide
Published: August 2024

Purpose

Coccidiosis caused by eimerian parasites results in lethal watery or bloody diarrhea in hosts, and markedly impairs the growth of and feed utilization by host animals. We previously investigated detailed the life cycle of Eimeria krijgsmanni as a mouse eimerian parasite. Only second-generation meronts, as an asexual stage, were morphologically detected in the epithelium of the host cecum for at least 8 weeks after infection, even though oocyst shedding finished approximately 3 weeks after infection. The presence of zoites was of interest because infection by eimerian parasites is considered to be self-limited after their patent period.

Methods

To clarify the significance of residual second-generation meronts in E. krijgsmanni infection, we performed infection experiments using immunocompetent mice under artificial immunosuppression and congenital immunodeficient mice.

Results

The number of oocysts discharged and the duration of oocyst discharge both increased in immunosuppressed mice. In immunodeficient mice, numerous oocysts were shed over a markedly longer period, and oocyst discharge did not finish until 56 days after inoculation.

Conclusions

The present results suggest that the second-generation meronts survived in the epithelial cells of the cecum after the patent period, thereby contributing to extended infection as an asexual stage. The results obtained on E. krijgsmanni indicate that infections by Eimeria spp. are not self-limited and potentially continue for a long period of time.
In search of per capita effects of Prunus serotina Ehrh. invasion on temperate forest understory alpha diversity
Authors: Bury Sebastian , Jagodziński Andrzej M. , Dyderski Marcin K.
Published: August 2024

Prunus serotina is one of the most widespread alien tree species in temperate European forests. Although numerous studies revealed both negative and positive impacts on native ecosystems, only a few assessed the quantitative impacts along a species abundance gradient, based on aboveground biomass of per capita effects. Here we studied how alpha diversity of forest understory changes with increasing aboveground biomass of P. serotina. In Wielkopolska National Park (W Poland) we established 92 plots in both nutrient-rich and poor Pinus sylvestris stands. We assessed the effects of P. serotina proportion on understory species composition using non-metric multidimensional scaling (NMDS). We also assessed the effects of P. serotina proportion on alpha diversity metrics using generalized mixed-effects linear models, accounting also for stand age, soil C:N ratio, and light availability. P. serotina biomass ranged from 0.0 to 34.29 Mg ha−1 (with an average of 5.70 ± 0.83 Mg ha−1), comprising 0% to 17.26% (with an average of 2.93 ± 0.43%) of total woody species biomass. NMDS revealed a lack of P. serotina proportion effects on understory species composition. We found small positive impacts of P. serotina proportion on total species richness (+ 8.8 species along a gradient with a 10% increase of P. serotina biomass proportion) and functional richness (+ 0.08). The positive impacts of P. serotina were mostly related to the confounding effect of two factors: an increase in light availability facilitates both the development of understory plants as well as the growth of P. serotina.
Assessment of the Microstructural Evolution of Naturally Aged Open-Cell Al-1.96Cu (at.%) Foams
Authors: Azamar M. F. , Hernández R. , Figueroa I. A. , Gonzalez G. , Novelo-Peralta O. , Lara-Rodríguez G. A. , Alfonso I.
Published: August 2024

Open-cell Al-1.96Cu (at.%) foams were produced by the replication casting technique in a 2.00–2.38 mm cell size. The produced foams were solution-treated at 535 °C for 5.5 h. Afterward, natural aging occurred at room temperature for 12, 24, and 36 months, and as a reference artificial aging at 170 °C for 8 h was also reported. The microstructural evolution of the studied samples was assessed through X-ray diffraction, the Rietveld refinement technique, and transmission electron microscopy. In addition, Vickers microhardness tests were carried out for all testing conditions. It was found that the lattice parameter of the supersaturated α-Al phase increased progressively with the natural aging at room temperature, which was attributed to the diffusion from the solid solution of the initially supersaturating Cu atoms toward Guinier–Preston zones and Cu-rich precipitates, thereby relaxing the Al lattice. In addition, it was demonstrated that the microstructure after natural and artificial aging is different.
Beyond the smile: a systematic review of diagnostic tools for peripheral facial paralysis
Authors: Tedeschi Roberto , Donati Danilo , Giorgi Federica
Published: August 2024

Background

Effective rehabilitation of peripheral facial paralysis (PFP) requires reliable assessment tools. This systematic review aimed to identify and validate instruments used in PFP rehabilitation, categorizing them according to the ICF framework.

Methods

A comprehensive search was conducted across PubMed, Cinahl, Web of Science, and Scopus up to April 2024. Observational analytical studies and one non-randomized controlled trial that validated tools for assessing PFP were included.

Results

Thirty-three studies were included, covering twenty different tools. Seventeen tools were related to the "Structure and Function" domain, while three addressed "Activity and Participation." The Sunnybrook and House-Brackmann scales were the most extensively studied. The Sunnybrook scale exhibited excellent intra- and inter-rater reproducibility and internal validity, making it suitable for clinical use. The House-Brackmann scale was user-friendly but had limitations in reproducibility and sensitivity to subtle differences, which newer versions like the FNGS 2.0 aimed to address. The FAME scale showed promise by reducing subjective scoring. Computerized tools, such as eFACE and A-FPG, and instruments for lip asymmetry and ocular involvement demonstrated potential but require further validation. The Facial Disability Index and the FaCE Scale were validated for assessing disability and participation restrictions.

Conclusion

This review identified several validated tools for PFP assessment, with the Sunnybrook and House-Brackmann scales being the most reliable. While emerging tools and computerized programs show promise, they need further validation for routine clinical use. Integrating validated tools into clinical practice is essential for comprehensive assessment and effective rehabilitation of PFP.
Trajectories and predictive significance of inflammatory parameters for clinical outcome in COVID–19 patients treated with tocilizumab
Authors: Killer Alexander , Gliga Smaranda , Massion Pascal , Ackermann Carla , De Angelis Clara , Flasshove Charlotte , Freise Noemi , Lübke Nadine , Timm Jörg , Eberhardt Kirsten Alexandra , Bode Johannes , Jensen Björn-Erik Ole , Luedde Tom , Orth Hans Martin , Feldt Torsten
Published: August 2024

Purpose

The IL-6 receptor inhibitor tocilizumab reduces mortality and morbidity in severe cases of COVID-19 through its effects on hyperinflammation and was approved as adjuvant therapy. Since tocilizumab changes the levels of inflammatory markers, we aimed to describe these changes in patients treated with tocilizumab, analyse their value in predicting death and bacterial superinfection and determine their influence on mortality rates.

Methods

A retrospective analysis of 76 patients who were treated with tocilizumab for severe COVID-19 in 2020 and 2021 was conducted. Inflammatory markers (IL-6, C-reactive protein (CRP), procalcitonin) were documented before and up to seven days after tocilizumab administration.

Results

The overall mortality was 25% and 53.8% in patients who required invasive respiratory support. Deceased patients had higher baseline IL-6 (p = 0.026) and peak IL-6 levels after tocilizumab vs those who survived (p < 0.0001). A peak IL-6 value > 1000 pg/dl after tocilizumab administration was a good predictor of mortality (AUC = 0.812). Of the deceased patients 41.1% had a renewed CRP increase after an initial decrease following tocilizumab administration, compared to 7.1% of the surviving patients (p = 0.0011). Documented bacterial superinfections were observed in 35.5% (27/76) of patients, of whom 48.1% (13/27) died.

Conclusion

CRP-decline and IL-6 increase after tocilizumab treatment occurs regularly. An increase of IL-6 levels exceeding tenfold of baseline IL-6 levels, an absolute peak of 1000 pg/ml or a renewed increase of CRP are associated with higher mortality. Suppressed CRP synthesis can impede the diagnosis of bacterial superinfections, thus increasing the risk for complications.
‘Athletes’, ‘Talents’, and ‘Players’: Conceptual Distinctions and Considerations for Researchers and Practitioners
Authors: Grainger Adam , Kelly Adam L. , Garland Stephen W. , Baker Joseph , Johnston Kathryn , McAuley Alexander B. T.
Published: August 2024

A clearer understanding of, and tighter boundaries between, terms are important for researchers designing studies as well as for other sport stakeholders creating evidence-informed policies. This article considers the terms ‘athlete’, ‘talent’, and ‘player’ from psychological and sociocultural perspectives and in different sporting communities to highlight the importance of terminological clarity in sport research. We present considerations to clarify the use of these terms within different contexts and how the use of specific terms may affect knowledge mobilization in diverse sporting populations. A conceptual discussion is provided to help operationalize development-related terminology and its associated stages, to better reflect contemporary academic thought, and enhance practical interpretations. Importantly, we also call for greater transparency from researchers when presenting findings and encourage practitioners to clearly define key terms when working in sport. Our intention in this paper is to energize readers to consider how we use language in athlete identification and development contexts, to stimulate deeper thought and discourse around the possible implications these terms may have at any point of an individual’s development in sport. Greater deliberation, identification, and acknowledgment of the drawbacks accompanying these terms will be needed before more confident assertions can be made on how researchers and practitioners could (or even should) implement certain terminology across youth sport contexts moving forward. This paper adds to a growing literature on the importance of clarity in terminology and acts as an impetus for those working in specific sports to co-design key terms used by researchers, practitioners, and policy makers.
Strengthening mechanism of different morphologies of nano-sized MSH on tribological performance of phosphate/MoS2 bonded solid lubricating coatings
Authors: Xi Zhengchao , Sun Jianbo , Chen Lei , Cui Haixia , Ma Yanjun , Zhou Huidi , Chen Jianmin
Published: August 2024

Magnesium silicate hydroxides (MSHs) with granular, schistose, and tubular morphologies were separately incorporated to enhance the tribological properties of phosphate/MoS2 composite coatings. The nano-schistose MSH demonstrated superior tribological performance due to its effective interactions with the worn surface and frictional synergies with solid lubricants. Incorporation of nano-schistose MSH decreased the friction coefficient of composite coatings by about 34.7% and increased the anti-wear performance of composite coatings by about thirteen times. Nano-schistose MSH facilitated the formation of a friction-induced multi-layer heterogenous slipping structure with layered solid lubricants at the friction interface. Moreover, tribo-chemical reactions between nano-schistose MSH and worn surface promoted the in-situ formation of a cermet supporting film, and this also induced the gradual in-situ formation of a lubrication film on the top of worn surface. Consequently, the contact state between tribo-pairs was timely regulated and the invalidation of the nanocomposite slipping structure was effectively restrained during the friction process. As a result, the service life of the phosphate composite coatings was significantly extended and further abrasion on the worn surface was notably reduced.
A model for the canonical algebras of bimodules type (1, 4) over truncated polynomial rings
Authors: Geiss Christof , Reynoso-Mercado David
Published: August 2024

Let $$\mathbb {C}(\!(\varepsilon )\!)$$

C
(

(
ε
)

)

be the field of complex Laurent series. We use Galois descent techniques to show that the simple regular representations of the species of type $$(1,\, 4)$$

(
1
,

4
)

over $$\mathbb {C}(\!(\varepsilon )\!)$$

C
(

(
ε
)

)

are naturally parametrized by the closed points of $$\textrm{Spec}(\mathbb {C}(\!(\varepsilon )\!)[x]){\dot{\cup }}\{1,\,2\}$$

Spec

(
C

(

(
ε
)

)

[
x
]

)

∪
˙

{
1
,

2
}

. Moreover, we provide weak normal forms for those representations. We use our representatives of the simple regular representations to describe the canonical algebras associated to the species of type (1, 4) over $$\mathbb {C}(\!(\varepsilon )\!)$$

C
(

(
ε
)

)

. This suggests a model of those algebras in the sense of the work of Geiss et al. (Invent Math 209(1):61–158, 2017; Math Z 295:1245–1277, 2020).
Breaking Barriers and Building Opportunities: Employer Perspectives on Working with People with Psychosocial Disabilities in a Rural Setting in Kenya
Authors: Gitonga Isaiah , Anujuo Kenneth , Muia Esther N. , Ebuenyi Ikenna D.
Published: August 2024

In low-resource settings where unemployment rates are already high, persons with disabilities experience even greater challenges in finding work and employment opportunities. While employers' viewpoints are critical to shaping organizational cultures and employment practices, their perspectives on the employment of people with psychosocial disabilities (PWPD) in rural settings have not been adequately examined. This study explored perspectives of rural employers in Kenya on working with and employing PWPD, so as to strengthen the practice of inclusive work and employment. We utilized a qualitative research methodology to explore the perspectives of a heterogeneous group of employers from Tana River County Kenya. A total of 12 employers participated in the study. We found that employer awareness of inclusive employment practices of PWPD is limited, with several barriers identified. Reported barriers include productivity concerns, occupational hazards, brand image, and disclosure. To improve work and employment rates for PWPD, employers highlighted workplace adjustments, holistic socioeconomic empowerment, and policy changes. Despite differing opinions, employers expressed a willingness to work with and employ PWPD. This study sheds light on the current practices, perceived barriers, and enablers for improving work and employment rates of PWPD in rural settings. While there is a lack of awareness among employers and multiple barriers, it is encouraging to note that employers are willing to work with and employ PWPD. To achieve this, a holistic approach that includes raising awareness on mental illnesses and implementing policies that promote inclusivity is needed.
Hunting for massive binaries with a black-hole component using Gaia data
Authors: Janssens Soetkin , Shenar T. , Sana H. , Faigler S. , Langer N. , Marchant P. , Mazeh T. , Schürmann C. , Shahaf S.
Published: August 2024

With the upcoming third Gaia data release (DR3), the first Gaia astrometric orbital solutions for binary sources will become available. Potentially, many rarely seen single-degenerate massive binaries with a black hole (OB+BH) will be revealed. Here, we investigate how many OB+BHs are expected to be detected as binaries in Gaia astrometry by using tailored models for the massive star population. We use a method based on the astrometric data to investigate how many OB+BH binaries will be uncovered by Gaia. We estimate that ∼200 OB+BHs are detectable among the sources in the second Alma Luminous Star massive star catalogue, either in DR3 or in upcoming data releases. Moreover, we show that BH-formation scenarios could be constrained from the distributions of parameters such as the orbital periods and eccentricities.
Quantitative spectroscopy of mid B-type supergiants
Authors: Weßmayer David , Przybilla Norbert , Butler Keith
Published: August 2024

B-type supergiants show enormous potential as resourceful tools to address a wide range of astrophysical questions concerning stellar atmospheres, stellar and galactic evolution and the cosmic distance scale. For the purposes of a comprehensive analysis of these objects we test a hybrid non-LTE approach – line-blanketed model atmospheres computed under the assumptions of local thermodynamic equilibrium (LTE) in combination with non-LTE line-formation calculations. An observational sample of 14 Galactic B-type supergiants with masses below about 30 Mȯ is investigated on the basis of high-resolution Echelle spectra. The results of this analysis – atmospheric and fundamental stellar parameters, the characterisation of the interstellar sightlines to the objects, as well as derived spectroscopic distances and multi-species abundances – are subjected to multiple tests of consistency.
Investigating the impact of different velocity fields on the spectral appearance of Wolf-Rayet stars
Authors: Lefever R. R. , Shenar T. , Sander A. A. C. , Poniatowski L. , Dsilva K. , Todt H.
Published: August 2024

The emission line spectra of WR stars are often formed completely in the optically thick stellar wind. Hence, any assumption on the wind velocity law in a spectral analysis has a profound impact on the determination of the stellar parameters. By comparing Potsdam Wolf-Rayet (PoWR) model spectra calculated with different β laws, we show that the velocity field heavily influences the spectra: by using the appropriate β laws, the entire range of late and early types can be covered with the same stellar model.
Spectroscopic analyses of massive stars at different metallicities
Authors: Hamann Wolf-Rainer
Published: August 2024

Adequate stellar atmosphere models are prerequisite to derive robust stellar parameters from spectroscopic analyses. I will briefly review recent results obtained with the Potdam Wolf-Rayet (PoWR) model atmosphere code, which is applicable to all types of hot stars. Using multi-wavelength observations including the UV, we analyzed large samples of massive stars at various metallicities, gaining important insights on their cosmic role and the feedback to their environment.

A recent extension of PoWR allows to compose the model atmosphere from two zones. A rapidly rotating star, e.g., might possess a cooler equatorial region with a slow wind, and two polar cones with higher photospheric temperature and fast wind. For two examples of rapidly rotating O-type stars, we demonstrate that such model can reproduce wind-line profiles which otherwise would stay inconsistent. Fast rotation, which prevails in particular at low metallicities, thus might bias empirically derived parameters, having implications for feedback as well as for angular-momentum losses of SN and GRB progenitors.
Intrinsic polarization of Wolf-Rayet stars due to the rotational modulation of the stellar wind
Authors: Abdellaoui Slah , Krtička Jiří , Kurfürst Petr
Published: August 2024

Wolf-Rayet stars are regarded as candidates for progenitors of core-collapse supernovae, and they are expected to be progenitors of long gamma-ray bursts. These types of stars are considered to be fast rotators. Their high rotation speed breaks the sphericity of the star and leads to an axisymmetric wind density structure. In such a case, the electron scattering takes place in a nonspherical environment, and as a result, we might expect an intrinsic polarization. We present a 2.5D radiation hydrodynamic stellar wind model of these stars. The model simulations account for the deformation of the stellar surface due to rotation, gravity darkening, and nonradial forces. We computed the polarization from the density variable of the hydrodynamic model, derived the upper limit of rotational velocities, and found no conflict with the previous studies of Wolf-Rayet stars.
The clumped winds of the most massive stars
Authors: Brands Sarah A. , de Koter Alex , Bestenlehner Joachim M. , Crowther Paul A. , Sundqvist Jon O. , Puls Joachim , Caballero-Nieves Saida M. , Abdul-Masih Michael , Driessen Florian A. , García Miriam , Geen Sam , Gräfener Götz , Hawcroft Calum , Kaper Lex , Keszthelyi Zsolt , Langer Norbert , Sana Hugues , Schneider Fabian R. N. , Shenar Tomer , Vink Jorick S.
Published: August 2024

The core of the cluster R136 in the Large Magellanic Cloud hosts the most massive stars known. The high mass-loss rates of these stars strongly impact their surroundings, as well as the evolution of the stars themselves. To quantify this impact accurate mass-loss rates are needed, however, uncertainty about the degree of inhomogeneity of the winds (‘wind clumping’), makes mass-loss measurements uncertain. We combine optical and ultraviolet HST/STIS spectroscopy of 56 stars in the core of R136 in order to put constraints on the wind structure, improving the accuracy of the mass-loss rate measurements. We find that the winds are highly clumped, and use our measured mass-loss rates to test theoretical predictions. Furthermore we find, for the first time, tentative trends in the wind-structure parameters as a function of mass-loss rate, suggesting that the winds of stars with higher mass-loss rates are less clumped than those with lower mass-loss rates.
An exploration of Cygnus OB2 and perspectives for the upcoming WEAVE High-Resolution Cygnus Survey
Authors: Berlanas Sara R. , Herrero Artemio
Published: August 2024

During the last years we have carried out different studies in the Cygnus OB2 association based on new spectroscopic data and benefiting from the unprecedented Gaia astrometry. They include membership, chemical and structure studies, that allowed us to discern for the first time ever between two stellar groups separated by several hundred parsecs within the association and find at least two star-forming bursts at ∼3 and ∼5 Myr. Using these studies as a template and combining upcoming spectroscopic WEAVE data and the expected accuracy that Gaia will reach in the Cygnus-X area (DR3 and forthcoming releases), we will be able to perform the deepest multi-dimensional study ever done before in a massive star-forming complex. The results of this project will lead to an important improvement of our knowledge of star formation and evolution of star-forming regions and clusters, including our understanding of the dynamics and kinematics of OB associations and stellar groups.
Massive stars in metal-poor dwarf galaxies are often extreme rotators
Authors: Schootemeijer Abel , Lennon Danny J. , Garcia Miriam , Langer Norbert , Hastings Ben , Schürmann Christoph
Published: August 2024

We probe how common extremely rapid rotation is among massive stars in the early universe by measuring the OBe star fraction in nearby metal-poor dwarf galaxies. We apply a new method that uses broad-band photometry to measure the galaxy-wide OBe star fractions in the Magellanic Clouds and three more distant, more metal-poor dwarf galaxies. We find OBe star fractions of ∼20% in the Large Magallanic Cloud (0.5Zȯ), and ∼30% in the Small Magellanic Cloud (0.2Zȯ) as well as in the so-far unexplored metallicity range 0.1 Z/Zȯ < 0.2 occupied by the other three dwarf galaxies. Our results imply that extremely rapid rotation is common among massive stars in metal-poor environments such as the early universe.
Formation of Supermassive Stars and the Direct Collapse to Black Holes
Authors: Regan John A.
Published: August 2024

Supermassive stars represent a promising avenue for seeding the (super-)massive black holes observed in the centres of massive galaxies. In these proceedings I review the motivation on the need for supermassive stars as a progenitor pathway for seeding massive black holes. I discuss the currently understood limitations of seeds produced by less massive stars (i.e. remnants from the first generation of stars) and advocate that more massive stars - with masses up to M∗ ∼ 105Mȯ - formed under the conditions of hierarchical structure formation, in rare haloes, are the favoured pathway. Finally, I discuss some recent high resolution simulations demonstrating the formation of supermassive stars in early galaxies.
New self-consistent wind parameters to fit optical spectra of O-type stars
Authors: Gormaz-Matamala Alex Camilo
Published: August 2024

We perform spectral fittings for O-type stars based on self-consistent wind solutions, providing Ṁ and ν(r directly derived from the initial stellar parameters. We introduce our two methods: m-CAK prescription and Lambert-procedure.

The Lambert-procedure allows the calculation of consistent v(r) that reduce the number of free parameters when a spectral fitting using CMFGEN is performed, even without recalculation of the Ṁ. Spectra calculated from our Lambert-solutions show significant differences compared to the initial β-law CMFGEN models. For m-CAK prescription, self-consistent solutions provide values for theoretical Ṁ on the order of the most recent predictions from other studies. Later, we find a global fit with the RT code FASTWIND. This is an important step towards the determination of stellar and wind parameters without using β-law. Our m-CAK prescription is valid for the O-type stars with Teff ≥ 30 kK and log g ≥ 3.2.

We expect that solutions introduced here to be extended to numerous studies about massive stars in future.
Fundamental Properties of O and B Stars with Optical Interferometry
Authors: Gordon Kathryn D. , Gies Douglas R. , Schaefer Gail H.
Published: August 2024

We used interferometric observations made with the CHARA Array of 25 B-type stars and 6 O-type stars to obtain precise measurements of angular size, radius, and effective temperature to test stellar atmospheric models for massive stars. Our measured angular diameters range from 1.09 milli-arcseconds (mas) for β Tau down to 0.11 mas for 10 Lac, the smallest star yet resolved with the CHARA Array. The rotational oblateness of the rapidly rotating star ζ Oph is directly measured for the first time. We collected ultraviolet to infrared spectrophotometry for all sample stars and derived temperatures, angular diameters, and reddening estimates that best fit the spectra. There is generally good agreement between the observed and spectral fit angular diameters for the O and B stars, indicating that the fluxes predicted from model atmospheres are reliable. The derived and model temperatures for the O stars are also in fair agreement, however the sample size is small and several of the O stars results we consider to be preliminary. On the other hand, the temperatures derived from angular diameters and fluxes tend to be larger (by ≈ 4%) for the B stars than those from published results based on analysis of the line spectrum (Gordon et al. 2018, 2019).
Magnetic massive stars from stellar mergers
Authors: Schneider Fabian R. N. , Ohlmann Sebastian T. , Podsiadlowski Philipp , Röpke Friedrich K. , Balbus Steven A. , Pakmor Rüdiger , Springel Volker
Published: August 2024

The first magnetic field in a star other than the Sun was detected in 1947 in the star 78 Vir. Today, we know that about 10% of these intermediate-mass and high-mass stars have strong, large-scale surface magnetic fields whose origin has remained a mystery till today. It has been suggested that merging of main-sequence and pre-main-sequence stars could produce such strong fields. The massive star τ Sco is a well-known member of the group of magnetic stars and is a blue straggler given its apparently young age compared to that of other members of the Upper Scorpius association. Here, we present 3D magnetohydrodynamic simulations of the coalescence of two massive main-sequence stars and 1D stellar evolution computations of the subsequent evolution of the merger product that can explain τ Sco’s magnetic field, apparent youth and other observed characteristics. We argue that field amplification in stellar mergers is a general mechanism to form strongly-magnetised massive stars. Such stars are promising progenitors of magnetars, which may give rise to some of the enigmatic fast radio bursts, and their supernova explosions may be affected by the strong magnetic fields.
Mass loss and the Eddington parameter
Authors: Bestenlehner Joachim M.
Published: August 2024

Mass loss through stellar winds plays a dominant role in the evolution of massive stars. Very massive stars (VMSs, > 100Mȯ) display Wolf-Rayet spectral morphologies (WNh) whilst on the main-sequence. Bestenlehner (2020) extended the elegant and widely used stellar wind theory by Castor, Abbott & Klein (1975) from the optically thin (O star) to the optically thick main-sequence (WNh) wind regime. The new mass-loss description is able to explain the empirical mass-loss dependence on the Eddington parameter and is suitable for incorporation into stellar evolution models for massive and very massive stars. The prescription can be calibrated with the transition mass-loss rate defined in Vink & Gräfener (2012). Based on the stellar sample presented in Bestenlehner et al. (2014) we derive a mass-loss recipe for the Large Magellanic Cloud using the new theoretical mass-loss prescription of Bestenlehner (2020).
Wind line variability and intrinsic errors in observational mass loss rates
Authors: Massa Derck , Prinja Raman
Published: August 2024

UV wind line variability in OB stars appears to be universal. We review the evidence that the variability is due to large, dense, optically thick structures rooted in or near the photosphere. Using repeated observations and a simple model we translate observed profile variations into optical depth variations and, consequently, variations in measured mass loss rates. Although global rates may be stable, measured rates vary. Consequently, profile variations infer how mass loss rates determined from UV wind lines vary. These variations quantify the intrinsic error inherent in any mass loss rate derived from a single observation. These derived rates can differ by factors of 3 or more. Our results also imply that rates from non-simultaneous observations (such as UV and ground based data) need not agree. Finally, we use our results to examine the nature of the structures responsible for the variability.
Formation of black holes in the pair-instability mass gap: Hydrodynamical simulation of a massive star collision & evolution of a post-collision star
Authors: Costa Guglielmo , Ballone Alessandro , Mapelli Michela , Bressan Alessandro , MacLeod Morgan
Published: August 2024

In this work, we study in detail the collision formation scenario of black holes (BHs) which lie in the pair-instability (PI) mass gap. We study the collision scenario of two massive stars by means of a smoothed-particle hydrodynamics (SPH) simulation and the post-collision evolution with detailed stellar evolutionary codes. We find that the stellar collision scenario is a suitable formation channel to populate the BHs’ PI mass gap.
Study of the Be/X-ray binary IGR J21343+4738 physical parameters based on the 15-years monitoring
Authors: Nikolaeva Evgeniia , Bikmaev Ilfan
Published: August 2024

We present the results of our long-term RTT-150 photometric and spectroscopic observations Be optical counterpart of the High-mass X-ray binary IGR J21343+4738.
Luminous red supergiants in the Magellanic Clouds
Authors: De Wit S. , Bonanos A. Z. , Tramper F. , Yang M. , Maravelias G. , Boutsia K. , Britavskiy N. , Zapartas M.
Published: August 2024

There is evidence that some red supergiants (RSGs) experience phases of episodic mass-loss. These episodes yield more extreme mass-loss rates, further stripping the envelope of the RSG, significantly affecting the further evolution towards the final collapse of the star. Mass lost through RSG outbursts/superwinds will flow outwards and form dust further out from the surface and this dust may be detected and modelled. Here, we aim to derive the surface properties and estimate the global properties of Mid-IR bright RSGs in the Magellanic Clouds. These properties will then be compared to evolutionary predictions and used for future spectral energy distribution fitting studies to measure the mass-loss rates from present circumstellar dust.
Access platform to our database of CMFGEN spectra for atmospheric studies of massive stars
Authors: Payen-Sandoval A. , Arias L. , Zargó J. , Arrieta A. , Fierro-Santillán C. R. , Klapp J.
Published: August 2024

We have collected a database of more than 43,000 spectra of atmospheres of massive stars. These spectra have been generated with the CMFGEN code of Hillier & Miller (1998) by systematically varying stellar parameters: effective temperature, luminosity, metallicity and mass loss rate for stars from 9 to 120 solar masses (Zsargó et al. 2020) In this work we present a web-based platform for accessing the database. The platform allows an online comparison between an observed and a synthetic spectrum to quickly assess the stellar and wind parameters. The platform will be available without cost to the astronomical community and will be hosted on servers shared between Mexican Universities.
Double Vision: Combining X-ray and Spectropolarimetric Observations of WR Binaries
Authors: Johnson R. A. , Nazé Y. , Panzera T. , Fullard A. G. , Lomax J. R. , Hoffman J. L. , Nordsieck K. H.
Published: August 2024

We present X-ray and spectropolarimetric observations of the WN+O binaries WR71 and WR97, which are analogs of the well-studied V444 Cygni. The combined results have the potential to constrain the locations and properties of wind interaction regions in these binaries, give clues to their subsequent evolution, and address the commonalities among WR+O systems.
Nuclear proteasomes buffer cytoplasmic proteins during autophagy compromise
Authors: Park So Jung , Son Sung Min , Barbosa Antonio Daniel , Wrobel Lidia , Stamatakou Eleanna , Squitieri Ferdinando , Balmus Gabriel , Rubinsztein David C.
Published: August 2024

Autophagy is a conserved pathway where cytoplasmic contents are engulfed by autophagosomes, which then fuse with lysosomes enabling their degradation. Mutations in core autophagy genes cause neurological conditions, and autophagy defects are seen in neurodegenerative diseases such as Parkinson’s disease and Huntington’s disease. Thus, we have sought to understand the cellular pathway perturbations that autophagy-perturbed cells are vulnerable to by seeking negative genetic interactions such as synthetic lethality in autophagy-null human cells using available data from yeast screens. These revealed that loss of proteasome and nuclear pore complex components cause synergistic viability changes akin to synthetic fitness loss in autophagy-null cells. This can be attributed to the cytoplasm-to-nuclear transport of proteins during autophagy deficiency and subsequent degradation of these erstwhile cytoplasmic proteins by nuclear proteasomes. As both autophagy and cytoplasm-to-nuclear transport are defective in Huntington’s disease, such cells are more vulnerable to perturbations of proteostasis due to these synthetic interactions.
Innovative voltammetric techniques for bumadizone analysis in pharmaceutical and biological samples: emphasizing green, white, and blue analytical approaches
Authors: Kelani Khadiga M. , Said Ragab A. , El-Dosoky Mohammad A. , Mohamed Ahmed R.
Published: August 2024

There are no documented electroanalytical methods for quantifying the anti-inflammatory drug bumadizone (BUM) in pharmaceutical or biological matrices. So, a new voltammetric method was developed to determine BUM at nano concentrations in pharmaceutical forms, in the presence of its alkaline degradant, and in biological fluids. Five electrodes were tested, including three nano-reduced graphene oxide (nRGO) electrodes (5%, 15%, and 20%), a carbon paste electrode (CPE), and a 10% nRGO-modified CPE. The 10% nRGO-modified electrode showed the best performance, offering high selectivity and low detection limits, with good linearity in the concentration range of 0.9 × 102 to 15 × 102 ng mL−1. Differential pulse voltammetry successfully applied this electrode for BUM determination in various samples, achieving excellent recovery without preliminary separation. The method was validated according to ICH guidelines and compared favorably to the reference method. Its environmental impact was assessed using AGREE and Eco-scale metrics in addition to the RGB algorithm, showing superior greenness and whiteness profiles due to safer solvents and lower energy consumption, along with high practical effectiveness using the BAGI metric.
Interplay of FXN expression and lipolysis in white adipocytes plays a critical role in insulin sensitivity in Friedreich’s ataxia mouse model
Authors: Wu Lin , Huang Fei , Yang Lu , Yang Liu , Sun Zichen , Zhang Jinghua , Xia Siyu , Zhao Hongting , Ding Yibing , Bian Dezhi , Li Kuanyu
Published: August 2024

Frataxin (FXN) is required for iron-sulfur cluster biogenesis, and its loss causes the early-onset neurodegenerative disease Friedreich ataxia (FRDA). Loss of FXN is a susceptibility factor in the development of diabetes, a common metabolic complication after myocardial hypertrophy in patients with FRDA. The underlying mechanism of FXN deficient-induced hyperglycemia in FRDA is, however, poorly understood. In this study, we confirmed that the FXN deficiency mouse model YG8R develops insulin resistance in elder individuals by disturbing lipid metabolic homeostasis in adipose tissues. Evaluation of lipolysis, lipogenesis, and fatty acid β-oxidation showed that lipolysis is most severely affected in white adipose tissues. Consistently, FXN deficiency significantly decreased expression of lipolytic genes encoding adipose triglyceride lipase (Atgl) and hormone-sensitive lipase (Hsl) resulting in adipocyte enlargement and inflammation. Lipolysis induction by fasting or cold exposure remarkably upregulated FXN expression, though FXN deficiency lessened the competency of lipolysis compared with the control or wild type mice. Moreover, we found that the impairment of lipolysis was present at a young age, a few months earlier than hyperglycemia and insulin resistance. Forskolin, an activator of lipolysis, or pioglitazone, an agonist of PPARγ, improved insulin sensitivity in FXN-deficient adipocytes or mice. We uncovered the interplay between FXN expression and lipolysis and found that impairment of lipolysis, particularly the white adipocytes, is an early event, likely, as a primary cause for insulin resistance in FRDA patients at later age.
Protein-derived Materials for Water Purification
Authors: Zahara Irum , Zubair Muhammad , Ullah Aman
Published: August 2024

Access to clean water is a fundamental right of every human. However, safe and secure drinking water is not available to everyone around the globe. Industrial wastewater is released into many freshwater bodies with nominal or without treatment. The discharged water has a very high concentration of heavy metals and dyes, which pollutes underground water streams. Most of the existing technologies for water treatment are very expensive and environmentally unfriendly, limiting their use in wastewater treatment. Bio-based materials, such as proteins, are of favorable choice because of their abundant natural availability, excellent adsorption properties, biocompatibility and non-ecotoxicity. Therefore, this chapter provides an overview of the current progress in protein-based materials for the remediation of water and wastewater contaminated with metal ions and organics.
Surface-enhanced Raman scattering enhancement using a hybrid gold nanoparticles@carbon nanodot substrate for herbicide detection
Authors: Aboualigaledari Naghmeh , Jayapalan Anitha , Tukur Panesun , Liu Mengxin , Tukur Frank , Zhang Yanling , Ducatte Gerald , Verma Madan , Tarus Janet , Hunyadi Murph Simona E. , Wei Jianjun
Published: August 2024

Hybrid nanoparticles composed of gold nanoparticles and carbon nanodots provide great signal amplification in SERS detection of herbicide molecules.
Crystallization-dictated assembly of block copolymers and nanoparticles under three-dimensional confinement
Authors: Hu Dengwen , Ji Xinyu , Zhu Jintao , Xu Jiangping
Published: August 2024

This feature article summarizes the recent progress in crystallization-dictated self-assembly of crystalline block copolymers and nanoparticles under spatial confinement, emphasizing the impact of crystallization on the assembly structure.
Recent progress of cataluminescence sensing based on gas–solid interfaces
Authors: Hu Jiaxi , Song Hongjie , Zhang Lichun , Lv Yi
Published: August 2024

The main advances of CTL sensors in methodologies and applications.
Borate-mediated aryl polyfluoroalkoxylation under transition-metal-free conditions
Authors: Kikushima Kotaro , Tsuda Tomoka , Miyamoto Naoki , Kita Yasuyuki , Dohi Toshifumi
Published: August 2024

We report boron-intermediary ligand transfer of diaryliodonium salt, synthesizing polyfluorolalkyl aryl ethers in the absence of transition metal catalyst or base.
Crystalline thiacalixarene assembly for adsorption ability toward linear and branched C6 alkane vapor isomers
Authors: Yamada Manabu , Yoshizaki Ruka , Anuar Faiq Sayfiyy Bin Shahril , Katagiri Hiroshi , Akimoto Kazuhiko , Hamada Fumio
Published: August 2024

A nonporous adaptive crystal constructed from thiacalix[4]arene molecules adsorbs di-branched C6 alkanes preferentially over mono-branched and linear C6 alkanes.
Red luminescent helical ribbons based on a non-polar charge-transfer complex
Authors: Zhang Jiacheng , Yao Lei , Li Wenju , Zhang Yongyi , Jin Tao , Wang Guan , Zhang Jing , Zhao Jianfeng
Published: August 2024

A non-polar charge-transfer supramolecular system twisted into a micro-helix structure with deep red emission, caused by unipolar alignment of cyano terminals and solvent–solute interactions.
Uncovering chemical homology of superheavy elements: a close look at astatine
Authors: Demidov Yuriy A. , Shalaevsky Alexander A. , Oleynichenko Alexander V. , Rusakov Alexander A.
Published: August 2024

What happens to periodic trends at the bottom of the periodic table? It's non-intuitive, complicated, and requires profound quantum-mechanical analysis.
Lab-on-a-lollipop (LoL) platform for preventing food-induced toxicity: all-in-one system for saliva sampling and electrochemical detection of vanillin
Authors: Ma Haozheng , Khazaee Nejad Sina , Vargas Ramos Daniel , Al-Shami Abdulrahman , Soleimani Ali , Amirghasemi Farbod , Mohamed Mona A. , Mousavi Maral P. S.
Published: August 2024

The lab-on-a-lollipop device collects and analyzes saliva in less than two minutes, making non-invasive saliva-based diagnostics more engaging and less uncomfortable.
Useful 1,2-dioxygenated dienes: syntheses and Diels–Alder reactions en route to substituted 2-naphthols and phenols
Authors: Teng Jiabing , Zhang Xifang , Song Ying , Chen Nayu , Zhang Yuanfei
Published: August 2024

The alkenylation reaction of vinylene carbonate with vinyl triflates using a Pd catalyst provides an access to 1,2-dioxygenated dienes, which undergo a tandem DA cycloaddition/decarboxylative aromatization reaction to give 2-naphthols and phenols.
When the liver is in poor condition, so is the heart – cardiac remodelling in MASH mouse models
Authors: Bott Sebastian , Lallement Justine , Marino Alice , Daskalopoulos Evangelos-Panagiotis , Beauloye Christophe , Esfahani Hrag , Dessy Chantal , Leclercq Isabelle Anne
Published: August 2024

Metabolic dysfunction-associated steatohepatitis (MASH) confers a risk for cardiovascular diseases in patients. Animal models may help exploring the mechanisms linking liver and heart diseases. Hence, we explored the cardiac phenotype in two MASH mouse models: foz/foz mice fed a high-fat diet (HFD) for 24 or 60 weeks and C57BL/6J mice fed a high-fat-, high-cholesterol-, and high-fructose diet for 60 weeks. Angiotensin II (AngII) was used as an additional cardiovascular stressor for 4 weeks in 10 weeks HFD-fed foz/foz mice. Foz/foz mice with fibrosing MASH developed cardiac hypertrophy with adverse cardiac remodelling not seen in WT similarly fed the HFD. AngII caused hypertension and up-regulated the expression of genes contributing to pathological cardiac hypertrophy (Nppa, Myh7) more severely so in foz/foz mice than in controls. After 60 weeks of HFD, while liver disease had progressed to burn-out non steatotic MASH with hepatocellular carcinoma in 50% of the animals, the cardiomyopathy did not. In an independent model (C57BL/6J mice fed a fat-, cholesterol- and fructose-rich diet), moderate fibrosing MASH is associated with cardiac fibrosis and dysregulation of genes involved in pathological remodelling (Col1a1, Col3a1, Vim, Myh6, Slc2a1). Thus, animals with MASH present consistent adverse structural changes in the heart with no patent alteration of cardiac function even when stressed with exogenous AngII. Liver disease, and likely not overfeeding or aging alone, is associated with this cardiac phenotype. Our findings support foz/foz mice as suitable for studying links between MASH and heart structural changes ahead of heart failure.