bluuebunny/crossref_metadata_2025 huggingface dataset:
Transition‐Metal‐Free Synthesis of 7‐Aminocoumarins from 7‐Hydroxycoumarins Using Multifunctional Reagent
Authors: Indurthi Harish K. , Das Samarpita , Saha Pallavi , Sharma Deepak K.
Published: February 2025

We have successfully synthesized N‐substituted 7‐aminocoumarins by reacting 7‐hydroxycoumarins with amines using 5,6‐dichloro‐2,3‐dicyanopyrazine, a readily available multifunctional reagent. This reagent effectively brings both coupling partners into close proximity, facilitating dehydrative C─N coupling reactions under mild, metal‐free conditions. Our approach demonstrates a broad substrate scope and enables gram‐scale production.
Red Color Tuning and Emission Enhancement in Thermally Stable Co‐Doped Ba3MoTiO8: Bi3+/Eu3+ Phosphors for Photo‐Electronic Applications
Authors: Rohilla Pooja , Malik Shristy , Kumari Sheetal , Prasad Aman , Rao A.S.
Published: February 2025

This research presents findings of various morphological and photoluminescence (PL) studies conducted on Bi3+/Eu3+ ions co‐doped Ba3MoTiO8 phosphors, which were synthesized using the common solid‐state reaction method. Phase analysis was conducted through X‐ray diffraction (XRD) technique. Morphological images and elemental composition were examined using field emission scanning electron microscopy (FESEM) and energy dispersive X‐ray (EDX) investigation. The nature and vibrational frequencies of bonds within the phosphor lattice were investigated using Fourier transform infrared (FT‐IR) spectroscopy. Photoluminescence studies were carried out under 272, 393, and 465 nm excitations, revealing the highest intensity peak at 615 nm, corresponding to the 5D0 → 7F2 transition of Eu3+ ions. The Commission Internationale de l'Eclairage (CIE) coordinates indicate that the synthesized phosphors emit in the red region. Decay curves under 272 and 393 nm excitation wavelengths exhibited single exponential behavior. We propose to use these phosphors as potential red‐emitting components in white light‐emitting diode (w‐LED), color tunable devices and other solid‐state lighting (SSL) applications.
Computational Study of Janusene/Crown as Model for Designing Molecular On/Off Switches by Host‐Guest Chemistry
Authors: Borosky Gabriela L. , Laali Kenneth K.
Published: February 2025

The janusene platform capped with a tetraethylene glycol moiety (JAN/crown) was employed as a model system to examine noncovalent interactions in its host‐guest (H‐G) complexes with various types of cationic and neutral guests. The spaces between the cofacial aromatic rings (interannular space) and the crown cavity were considered as inclusion regions, and the relative stabilities of both types of complexes were evaluated computationally. The interannular complexes proved to be less stable as compared to crown complexes, likely due to the required distortion in the JAN skeleton in order to accommodate the host. The possibility to design molecular on/off switches by migration of the cationic host from inside the crown cavity (the “off” switch) to the cofacial region between π‐stacked rings (the “on” switch) was analyzed.
Realizing Electrochemical Energy Conversion and Storage with Borophene: Science, Engineering, Obstacles, and Future Opportunities
Authors: Ajmal Saira , Huang Junfeng , Singh Monika , Kumar Anuj , Guo Jianwen , Tabish Mohammad , Mushtaq Muhammad Asim , Alam Mohammed Mujahid , Song Xinrui , Yasin Ghulam
Published: February 2025

A novel 2D material that is a formidable opponent to graphene (Gr) is borophene, which stands as 2D boron sheets. This innovative material has gained interest in the energy sector due to its wide range of chemical properties, intricate structural geometries, possession of massless Dirac fermions, outstanding hardness, and high carrier mobility. Unlike Gr, which lacks a band gap, borophene exhibits a band gap, endowing it with distinct advantages. Although many advancements in borophene materials, including their synthesis, structural and electronic characterization, and applications, have been discussed in the literature, there is still a need for a quantitative and qualitative assessment from both the experimental and theoretical perspectives, as well as the learned lesson implication in real‐world applications of this material. This review highlights recent theoretical and experimental discoveries about borophene, focusing on key scientific findings, structural and electronic properties, and diverse applications, particularly in energy conversion processes and energy storage systems such as batteries and supercapacitors. Finally, the paper discusses current research challenges and future opportunities for large‐scale borophene synthesis and its potential uses.
Essential Parameters for Optimizing Conical Journal‐Bearing Performance
Authors: Kulkarni Prasad D. , Phalle Vikas M. , Pawar Sanjay R. , Handikherkar Vishwadeep
Published: February 2025

A conical journal bearing (CJB) is a type of bearing with a tapered, conical shape that supports a rotating shaft, providing both radial and axial support. Its design allows for better load distribution and alignment compared to cylindrical bearings, making it suitable for specific applications where combined loads are present. Numerous factors, including lubrication, load capacity, bearing material, operating speed, clearance, and friction, affect the way CJBs work. These factors determine the efficiency, durability, and overall functionality of the bearing under different operational conditions. Finite element analysis (FEA) helps evaluate CJB performance by simulating stress and strain distributions, thermal behavior, and deformation under various loads. It also models lubrication flow, providing insights into how lubrication quality and distribution impact performance. This comprehensive analysis aids in optimizing bearing design and predicting failure points. The results of FEA in evaluating CJB performance reveal detailed stress and strain distributions, identify potential failure points, and predict thermal behavior under various load conditions. FEA also provides insights into deformation and lubrication flow, helping to optimize bearing design for improved load capacity, reduced friction, and enhanced durability. These findings enable engineers to make data‐driven decisions to enhance bearing performance and reliability.
Dynamic Wetting Characteristics and Quantitative Analysis of Reaction Behavior between CaO–Al2O3‐Based Mold Flux and Fe–Mn–Al–C Low‐Density Steel
Authors: Fan Lei , Li Songrong , Shi Yujie , Wang Zineng , Cao Boqing , He Faxiang , Qu Tianpeng , Wang Deyong , Li Xianglong , Hu Shaoyan , Hou Dong , Zhang Zhixiao , Yang Zhenghong
Published: February 2025

To design a low‐reactivity mold flux that met the requirements for continuous casting of Fe–Mn–Al–C low‐density steel, the reaction behavior between CaO–Al2O3‐based mold flux and low‐density steel is quantitatively analyzed. Based on this, the dynamic wetting characteristics between the mold flux and low‐density steel are further characterized during the steel‐slag reaction process. The results show that when the reaction time is within 20 min, the chemical reactions between [Al], [Mn] in the steel and (B2O3) in the mold flux mainly occur. When the reaction time increases from 20 to 30 min, the chemical reactions between [Al] and (B2O3), (SiO2) are dominant. The reaction degree is quantitatively characterized by mass balance calculation. The changes in the activity of components in mold flux and molten steel are analyzed theoretically. Moreover, with the increase in reaction time, the initial temperature of the rapid decrease of the contact angle gradually increases from 1363 to 1423, 1463, and 1493 K, respectively. With the increase in reaction time, the adhesion work of mold fluxes decreases first and then increases, but its maximum value is lower than 670.832 mJ m−2. This work provides theoretical guidance for the design and development of a low‐reactivity mold flux.
A Latent Space Approach to Inferring Distance‐Dependent Reciprocity in Directed Networks
Authors: Loyal Joshua Daniel , Wu Xiangyu , Stewart Jonathan R.
Published: February 2025

Reciprocity, or the stochastic tendency for actors to form mutual relationships, is an essential characteristic of directed network data. Existing latent space approaches to modelling directed networks are severely limited by the assumption that reciprocity is homogeneous across the network. In this work, we introduce a new latent space model for directed networks that can model heterogeneous reciprocity patterns that arise from the actors' latent distances. Furthermore, existing conditionally edge‐independent latent space models are nested within the proposed model class, which allows for meaningful model comparisons. We introduce a Bayesian inference procedure to infer the model parameters using Hamiltonian Monte Carlo. Lastly, we use the proposed method to infer different reciprocity patterns in an advice network among lawyers, an information‐sharing network between employees at a manufacturing company and a friendship network between high school students.
Augmenting Intelligence: The Convergence of ML/LLMs and Statistics
Authors: Carbonara Joaquin , Fokoue Ernest
Published: February 2025

The rapid advancements in artificial intelligence (AI), machine learning (ML), neural networks (NN) and language models (LM) research, coupled with the widespread availability of large language models as a service (LLMaaS), have begun to influence most domains, particularly the field of statistics, in unprecedented ways that are difficult to forecast. The awarding of two Nobel Prizes in 2024 for computational work in AI—to Hopfield and Hinton for their foundational discoveries and inventions in machine learning with artificial neural networks and to Baker, Hassabis and Jumper for developing an AI model to solve the longstanding problem of predicting proteins' complex structures—is a testament to the significant impact of AI in these fields. Two key contributors for the current revolution are statistics and data science. The merger of data science with AI research led to the creation of tools like LLMs, profound advancements in AI as a tool and speculations of humanity being close to creating AGI. These transformative technologies have opened up a vast array of opportunities, but they have also presented new challenges that necessitate careful consideration. Here, we discuss what is needed to successfully navigate these stormy times in the current sea of information surrounding us.
Monitoring Listening Comprehension in Real Time: Early Observations from the ReMoDEL Project
Authors: Siegel Joseph , Kuteeva Maria , Siegel Aki
Published: February 2025

Developing strong listening skills in a second language (L2) can be challenging for a variety of reasons. Within the context of L2 use in higher education, accurate and timely processing of aural input can be crucial for academic success, particularly because vast amounts of disciplinary‐specific content are delivered via academic lectures in the students' and/or teacher's L2. This brief report introduces and shares early observations from the ReMoDEL project (Real Time Monitoring of Dynamic English Listening), which focuses on student listening comprehension in English as a medium of instruction (EMI) courses set within a multicultural, multilingual context, namely, Sweden. Employing a novel footpedal device to register moments of comprehension and noncomprehension, ReMoDEL identifies instances within EMI lectures when students report challenges in understanding and investigates the cause(s) of those challenges with the overall aims of identifying the myriad influences on comprehension of lecture content, cataloging student recovery strategies, and working to raise teacher awareness of the volatile and individualized nature of listening in EMI. The combination of footpedal data and stimulated recall interviews yielded 89 coded instances of noncomprehension (including multiple coding, when appropriate) that arose during a pilot study, of which a majority related to top‐down aspects of listening (53), followed by affective, multimodal and environmental factors (10 each). Bottom‐up processing issues were sparsely reported (four), and two mistaken pushes occurred. This brief report describes the project as well as quantitative and qualitative data from the pilot study.
Diabetes mellitus exacerbates changes in white matter hyperintensity shapes and volume: A longitudinal study
Authors: Xu Shihao , Wang Yan , Chen Jiahui , Pan Zhiming , Wu Wenjun , Su Zhipeng , Wang Zhen
Published: February 2025

INTRODUCTION

Although white matter hyperintensity (WMH) can progress over time, little is known about the underlying mechanisms. In addition, type 2 diabetes mellitus (T2DM) exacerbates the accumulation of WMH. Here we aimed to investigate longitudinal changes in WMH shapes and volume in older adults with and without T2DM.

METHODS

Participants underwent baseline and follow‐up magnetic resonance imaging (MRI). WMH volume and shape markers were automatically assessed. We compared WMH volume and shape markers at baseline and follow‐up.

RESULTS

A total of 200 participants were included at baseline and 181 at follow‐up. The mean age ± SD of our study participants was 69.86 ± 6.03 years; 79 (39.90%) had a history of diabetes mellitus (T2DM) and 73 (36.50%) were male. For shape markers, participants with T2DM showed more complex periventricular (eccentricity, p = 0.027) and deep WMH shape markers (fractal dimension, p = 0.002) than participants without T2DM. At baseline, there were no statistically significant differences (p > 0.05) in WMH volume when participants with T2DM were compared to participants without T2DM. At follow‐up, a more complex shape of periventricular/confluent WMH on follow‐up (concavity index, p = 0.005; inverse sphericity index, p = 0.001). In addition, total (p < 0.001), periventricular (p < 0.001), and deep (p = 0.001) WMH volumes increased significantly.

DISCUSSION

A more irregular shape of periventricular and deep WMH and higher WMH volumes were associated with T2DM participants. These findings suggest that WMH shape markers may be useful in determining prognosis for cerebral small vessel disease and aid in future preventive treatments.

Highlights

Patients with diabetes mellitus have more irregular white matter hyperintensity (WMH) shapes and increased WMH volumes.

Diabetes mellitus exacerbates the changes in WMH shapes and volumes

WMH shape markers might have the potential to aid in future preventive treatments and prevent clinical deterioration.
Insights Into Multilingual Students to Capitalize on Their Language Knowledge
Authors: Ittner Anne C. , Jennerjohn Anna , Helman Lori
Published: February 2025

Classrooms with multilingual students are rich spaces for enacting linguistically sustaining practices that encourage students to use all their language resources. When teachers have some knowledge of their students' home languages, they can facilitate making connections across languages which strengthens students' language development. In this article, we provide a description of key ideas and practices that teachers of multilingual students need to know, so they can draw on the linguistic resources of their students. While there are many factors that contribute to the literacy development of multilingual students, we focus on the linguistic features (phonology, morphology, syntax, and semantics) of students' home languages and English. We share examples in multiple languages of how teachers can create linguistically sustaining practices in their classroom.
Catalytic ozone oxidation of chemical RO membrane concentrate wastewater by a Cu‐Ce@γ‐Al2O3 ozone catalyst
Authors: Sun Wenquan , Wang Yan , Yang Xingwang , Wang Ziran , Zhu Hanqing , Zhou Jun , Sun Yongjun
Published: February 2025

A Cu‐Ce@γ‐Al₂O₃ catalyst was developed for the efficient treatment of chemical reverse osmosis (RO) membrane concentrate wastewater. The working conditions and reaction mechanisms of Cu‐Ce@γ‐Al₂O₃ catalytic ozonation were systematically investigated, and its application in the catalytic ozonation of chemical RO membrane concentrate wastewater was explored. The catalyst was comprehensively characterized using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), X‐ray fluorescence (XRF), and Fourier‐transform infrared (FTIR) spectroscopy, revealing its microstructure, elemental composition, and crystal structure. The optimal reaction conditions were identified as follows: ozone dosage of 8 mg/L/min, initial pH of 9.0, catalyst filling ratio of 10%, and a reactor height‐to‐diameter ratio of 5:1. Under these conditions, the catalytic ozonation achieved a chemical oxygen demand (COD) removal rate of 63.4%. Free‐radical quenching experiments confirmed that hydroxyl radicals (·OH) played a dominant role in the catalytic ozonation system. Kinetic analysis revealed that the catalytic ozonation of chemical RO membrane concentrate wastewater with Cu‐Ce@γ‐Al₂O₃ followed second‐order kinetics. The degradation mechanisms of organic matter in the wastewater were further analyzed using ultraviolet–visible (UV–Vis) spectroscopy and three‐dimensional fluorescence spectroscopy. Additionally, a weighted rank sum ratio (WRSR) evaluation model was developed to provide a comprehensive assessment of the process performance.

Practitioner Points

Cu‐Ce@γ‐Al2O3 catalysts with excellent catalytic performance were prepared.

Efficient catalytic ozonation of chemical RO membrane concentrate with high salinity was realized.

Degradation mechanism of organic pollutants by catalytic ozonation is clarified.

Evaluation model for catalytic ozonation of chemical RO membrane concentrate was established.
Developments in Secure Random Number Generators
Authors: Deng Lih‐Yuan , Kumar Nirman , Lu Henry Horng‐Shing , Yang Ching‐Chi
Published: February 2025

Designs of pseudo‐random number generators have been divided into two areas of applications: computer simulation and computer security. The requirement for computer simulation application is long period length and great distributional property whereas generators for computer security need to be secure with unpredictability and a nice distributional property. Most popular secure ciphers have used similar strategies: (a) applying some long key expansion scheme to initialize internal state vectors without using external generators, (b) applying a complex sequence of ARX (Addition, Rotation, XOR) transformations to diffuse the initial state vectors and outputs via additional transformations. We discuss a general framework to design a class of random number generators suitable for both computer simulation and computer security applications. The key idea is to add several good external generators to the existing popular ciphers (with minimal changes) for the purpose of better initialization and continuously updating these internal vectors with external generators.
A classical Bousso bound for higher derivative corrections to general relativity
Authors: Bhattacharyya Sayantani , Biswas Parthajit , Kundu Nilay
Published: February 2025

Abstract

Focussing on theories for which the higher derivative terms are considered as small corrections in the Lagrangian to Einstein’s two-derivative theory of general relativity (GR), we prove the classical version of the covariant entropy bound (also known as the Bousso bound) in arbitrary diffeomorphism invariant gravitational theories. Even if the higher derivative corrections are treated perturbatively, we provide instances of specific configurations for which they can potentially violate the Bousso bound. To tackle this obstruction, we propose a modification in the Bousso bound that incorporates the offending contributions from the higher derivative corrections. We argue that the modified Bousso bound that we propose holds to all orders in the higher curvature corrections. Our proposed modifications are equivalent to replacing the Bekenstein-Hawking area term by Wald’s definition (with dynamical corrections as suggested by Wall) for the black hole entropy. Hence, the modifications are physically well motivated by results from the laws of black hole mechanics in higher derivative theories.
Notes on the factorisation of the Hilbert space for two-sided black holes in higher dimensions
Authors: Li Pan
Published: February 2025

Abstract

In this paper, we investigate the Hilbert space factorisation problem of two-sided black holes in high dimensions. We demonstrate that the Hilbert space of two-sided black holes can be factorized into the tensor product of two one-sided bulk Hilbert spaces when the effect of non-perturbative replica wormholes is taken into account. We further interpret the one-sided bulk Hilbert space as the Hilbert space of a one-sided black hole. Therefore, since the Hilbert space of a two-sided black hole can be obtained from the tensor product of two single-sided black hole Hilbert spaces, we consider this as an embodiment of the ER=EPR conjecture, and we show when the entanglement between the two single-sided black holes is sufficiently strong, the (Lorentzian) geometry of a two-sided black hole will emerge.
Directed Transit Functions
Authors: Anil Arun , Changat Manoj , Chavara John J. , K-Sheela Lekshmi Kamal , Narasimha-Shenoi Prasanth G. , Schmidt Bruno J. , Shanavas Ameera Vaheeda , Stadler Peter F.
Published: February 2025

Transit functions were introduced as models of betweenness on undirected structures. Here we introduce directed transit function as the directed analogue on directed structures such as posets and directed graphs. We first show that betweenness in posets can be expressed by means of a simple set of first order axioms. Similar characterizations can be obtained for graphs with natural partial orders, in particular, forests, trees, and mangroves. Relaxing the acyclicity conditions leads to a generalization of the well-known geometric transit function to the directed structures. Moreover, we discuss some properties of the directed analogues of prominent transit functions, including the all-paths, induced paths, and shortest paths (or interval) transit functions. Finally we point out some open questions and directions for future work.
Geometrical characterization of circular multi-layered CMT WAAM specimens by 3D structured light scanning
Authors: Lettori Jacopo , Esposto Cesare , Peruzzini Margherita , Pellicciari Marcello , Raffaeli Roberto
Published: February 2025

To ensure the geometric accuracy of wire arc additive manufacturing (WAAM) components, it is essential to analyze how process parameters influence the weld bead dimensions and shape. This paper presents a formal and repeatable procedure to entirely characterize the geometry of beads by enhanced full-coverage optical scanning with focus on multi-layered thin-walled closed specimens realized by the cold metal transfer (CMT) welding process. A series of circular specimens have been manufactured according to a DOE plan of process parameters, scanned with a GOM fringe projection 3D optical scanner, geometrically processed in the Rhinoceros 3D CAD environment, and analyzed by statistical indices according to the ANOVA approach. Average dimensions, lateral surface waviness, interaction between successive layers, and the torch switch-on/off zone of closed layer paths have been assessed. Numerical correlations between bead sizes and deposition parameters have been established. The obtained results also reveal shape and dimensional variability, highlighting the challenges in controlling geometry accuracy. Finally, process planning guidelines are formulated based on such results.
The metamathematics of separated determinacy
Authors: Aguilera J. P.
Published: February 2025

Determinacy axioms are mathematical principles which assert that various infinite games are determined. In this article, we prove three general meta-theorems on the logical strength of determinacy axioms. These allow us to reduce a metamathematical analysis of the principle of

$\Gamma $

Γ

-determinacy over a weak base theory to an analysis of a principle

$\Gamma '$

Γ
′

-determinacy, where

$\Gamma '$

Γ
′

is a strictly smaller complexity class than

$\Gamma $

Γ

. The meta-theorems are proved in the weak theory

${\mathsf{RCA_{0}}}$

R
C

A
0

. However, they are formulated in a general way and also have applications in the context of

${\mathsf{ZFC}}$

ZFC

, eventually leading to an optimal generalization of Martin’s Borel determinacy theorem and optimal strengthenings of the transfer theorems of Martin-Harrington, Kechris-Woodin, and Neeman. As the main application of the meta-theorems, we carry out all the reverse-mathematical analyses of theories of determinacy below

$T = \boldsymbol{\Pi }^{1}_{1}{-}{\mathsf{CA_{0}}}+ \Pi ^{1}_{4}{-}{ \mathsf{CA_{0}}}$

T
=

Π

1

1

−

C

A
0

+

Π

4

1

−

C

A
0

which are missing from the literature. More precisely, let

$\Gamma \subset \mathcal{P}(\mathbb{R})$

Γ
⊂
P
(
R
)

be called a Wadge class if

$\Gamma $

Γ

is closed under continuous preimages. For each Wadge class

$\Gamma $

Γ

such that the consistency of

$\Gamma $

Γ

-Determinacy is provable in

$T$

T

, we reduce the principle of

$\Gamma $

Γ

-Determinacy to a combination of Comprehension, Monotone Induction, and

$\beta $

β

-Reflection axioms. It follows from our results that these classes

$\Gamma $

Γ

are precisely those which satisfy

$$ o(\Gamma ) < \omega _{1}^{\omega _{1}^{2}} \text{ and $T\vdash $``$\Gamma $ is a Wadge class.''} $$

o
(
Γ
)
<

ω
1

ω

1

2

and 

T
⊢

“
Γ
 is a Wadge class.”

Our work extends and generalizes results of Friedman, Hachtman, Heinatsch, Martin, MedSalem, Montalbán, Möllerfeld, Nemoto, Shore, Steel, Tanaka, Welch, and others, and concludes the project of metamathematical analysis of determinacy principles (cf. e.g., Montalbán’s “Open Questions in Reverse Mathematics”, Bull. Symb. Log. 16:431–454, 2011), as far as subsystems of

$T$

T

are concerned.
Zufriedenheit und Herausforderungen im akademischen Mittelbau
Authors: Ohm Marc , Arlinghaus Clarissa Sabrina , Mertes Silvan
Published: February 2025

Die Lage des wissenschaftlichen Nachwuchses wird als angespannt wahrgenommen. Um das aktuelle Stimmungsbild dieser Gruppe in Deutschland besser zu verstehen, wurde eine umfassende Untersuchung durchgeführt. Zu diesem Zweck wurde eine Umfrage an die spezifische Zielgruppe versandt, um aktuelle Herausforderungen und Lösungsvorschläge in strukturierter Form zu erfassen. Die Resultate der Untersuchung offenbaren eine Vielzahl an Faktoren, welche die Arbeitssituation des wissenschaftlichen Nachwuchses beeinträchtigen. Dazu zählen insbesondere eine hohe Mehrfachbelastung, Überarbeitung sowie eine fehlende langfristige Perspektive, welche durch ständige Befristungen bedingt ist. Die befragten Personen äußerten deutlich den Wunsch nach Verbesserungen ihrer Arbeitsbedingungen. Dazu zählen beispielsweise längere Vertragslaufzeiten, geringerer Stress, unbefristete Stellen sowie ein stärkerer Schutz der physischen und psychischen Gesundheit.
Effect of high energy laser processing on defect and structural phase state of titanium products made by additive technologies
Authors: Len Evgen , Galstian Iryna , Gustmann Tobias , Gerasymov Olexandr , Savvakin Dmytro , Bondarchuk Vadim , Oryshych Denis
Published: February 2025

The microstructure, physical, and mechanical characteristics of 3D-printed metal products can be improved with high-energy heat treatment included in the manufacturing process. In the present study, Ti-6Al-4V titanium alloy products were 3D-printed with electron beam melting of wire of appropriate composition, while surface laser treatment of 3D-printed material was studied to determine the potential of microstructure modification and characteristics improvement. It was found that certain laser processing modes make it possible to eliminate micro defects (pores) in the samples that are harmful to structural materials. The obtained results also open the prospect of creating 3D-printed metal parts with specified profiles of physical and chemical properties, including gradients, as they model the change in material properties depending on the depth of the deposited layer during high-energy processing of each layer during its application. As demonstrated, both the condition of 3D printing as the velocity of deposition and thickness of each layer, the chemical composition and amount of impurities added to the matrix material during deposition, and the high-energy processing (heating or remelting) parameters are important to form the phase composition and mechanical properties of the final products. The high-energy processing also can be used to control the physicochemical properties of the product’s surface.
Characterization of 3D oxygen concentrations in hydrogels combining astigmatic particle tracking with phosphorescence decay measurements
Authors: Werner Till , Schmidt Mareike , Etzold Bastian J. M. , Fritschen Anna , Blaeser Andreas , Hussong Jeanette
Published: February 2025

In this work, we combine astigmatic particle tracking with phosphorescence decay measurements to determine 3D oxygen concentration distributions in microfluidic systems. Out-of-plane positions are reconstructed to an accuracy of 1.5 

$$\upmu$$

μ

m. The calibrated measurement range covers oxygen concentrations between 0.6 to 27.6 ppm. A method is presented to systematically correct for measurement errors caused by photobleaching taking into account the excitation energy, the cumulative laser irradiation time and the spatially varying intensity profile of the laser. With this method, low measurement errors of less than 2 ppm at ambient oxygen levels can be achieved even after thousands of excitation cycles. To demonstrate the capability of the measurement technique, 3D oxygen concentrations are measured in an agarose hydrogel filled microfluidic chamber across which different pressure and oxygen gradients can be set independently. The results show that oxygen diffusion is superposed by a convective transport of interstitial flow. By matching numerical simulations to the experimental data, further insights into the ratio of convective and diffusive transport are given and a methodology for estimating relevant material parameters is presented. This in situ measurement technique can be applied to improve the design process of supply networks for tissue models.

Graphical abstract
High risk of short-term mortality and postoperative complications in patients with generalized peritonitis undergoing major emergency abdominal surgery—a cohort study
Authors: Olausson Maria , Tolver Mette A. , Gögenur Ismail
Published: February 2025

Background

Secondary generalized peritonitis is a potentially life-threatening condition. The aim of this study was to investigate the association between secondary generalized peritonitis and short-term mortality and postoperative complications in patients undergoing major abdominal emergency surgery.

Methods

The study included patients with the age ≥ 18 years undergoing major emergency abdominal surgery in a University Hospital from 2017 to 2019 after the introduction of a perioperative bundle care program. The primary outcome measures were short-term mortality, defined as death within 30 and 90 days after surgery and postoperative complications within 30 days after surgery. Uni- and multivariable logistic regression analyses were performed to evaluate risk factors for 30- and 90-days mortality and 30-days postoperative complications.

Results

A total of 591 patients were included, of whom 21% (124/591) had generalized peritonitis. The overall 30 day-mortality rate was 12.5% (74/591). Patients with generalized peritonitis had a significantly higher 30-day mortality rate than patients with non-generalized peritonitis 18.5% (23/124) vs. 10.9% (51/467), P = 0.033. Generalized peritonitis was an independent risk factor for 30- and 90- days mortality. There was a significantly higher rate of admission to ICU for patients with generalized peritonitis 39.5% (49/124) vs. 12.6% (59/467), P < 0.001. Patients with generalized peritonitis had significantly higher rates of surgical and non-surgical complication compared to patients with non-generalized peritonitis 87.1% (108/124) vs. 65.7% (307/467), P < 0.001. Generalized peritonitis was an independent risk factor of 30 days postoperative complications.

Conclusion

In a population undergoing major emergency abdominal surgery treated in a perioperative optimization protocol, generalized peritonitis was an independent risk factor for both 30- and 90-days mortality and postoperative complications.
Can viral load predict a symptomatic congenital CMV infection? A systematic review and meta-analysis
Authors: Salomè Serena , Gammella Roberta , Coppola Clara , Dolce Pasquale , Capasso Letizia , Blázquez-Gamero Daniel , Raimondi Francesco
Published: February 2025

Cytomegalovirus (CMV) is the most common cause of congenital infection. Although only 10% of infected newborns are symptomatic at birth, a clinical disease may develop later in infancy. An early diagnosis of symptomatic congenital CMV is important for successful treatment. The aim of this study was to evaluate if a higher viral load in different biological fluids at the time of diagnosis correlates with symptomatic disease. A systematic search of Medline, Embase, and SCOPUS from 1976 to August 2024 was performed. Studies were included if the viral load was clearly identifiable as median and mean. Two independent reviewers completed screening, full-text review, data extraction, and quality assessment. Study results were reported as median and interquartile range (IQR: Q1–Q3), with group comparisons based on median differences. Pooled estimates of median differences with 95% confidence intervals were obtained using a median-based meta-analysis approach. Of 4558 studies identified, 11 were used in the meta-analysis with a total of 796 patients (376 symptomatic and 420 asymptomatic babies) for blood determinations and 919 patients for urine (331 symptomatic and 588 asymptomatic babies). Symptomatic infants showed significant higher viral load in blood (pooled difference of median = 1.77 × 104, 0.82;2.72 IU/mL) and a trend in urine (pooled difference of median = 339.7 × 104, − 22.2;701.43 IU/mL).

Conclusion: In conclusions, we provide preliminary data that a high CMV load in blood and urine may be associated with symptomatic disease in newborns. Wider and more homogeneous evidence is warranted to confirm our conclusions and to identify a threshold for patients at risk of clinical disease.

What is Known:

• CMV is the most common cause of congenital infection and an early diagnosis of symptomatic disease is important for successful treatment. A higher viral load in blood was supposed to correlate with symptomatic disease but with non-unique results and data are lacking for different biological fluids.

What is New:

• We provide preliminary data that a great CMV load in blood and urine may predict newborns at risk of symptoms. Wider and more homogeneous evidence is warranted to confirm our conclusions and to identify a specific viral load threshold for patients at risk of clinical disease.
Vitamin D status and muscle strength in a pan-European cohort of children and adolescents with normal weight and overweight/obesity
Authors: Zeeb Hajo , Brand Tilman , Lissner Lauren , Lauria Fabio , Molnár Dénes , Veidebaum Toomas , Nauck Matthias , Tornaritis Michael , De Henauw Stefaan , Moreno Luis A. , Ahrens Wolfgang , Pohlabeln Hermann , Wolters Maike ,   On behalf of IDEFICS and I.Family consortia
Published: February 2025

This aimed to investigate associations between the vitamin D status and handgrip strength in children and adolescents considering weight status. Participants aged 7 to < 16 years from the European IDEFICS/I.Family cohort were included. Serum 25-hydroxyvitamin D [25(OH)D] and handgrip strength were measured in 2013/2014. In multivariable logistic regression models, we investigated the association of vitamin D status with handgrip strength adjusted for demographic variables, BMI z-score, sports club membership, screen time and UV intensity. Vitamin D-sufficient children had higher odds for a high handgrip strength (OR = 1.92, 95%-CI: 1.12, 3.30), but this association was limited to children with thinness/normal weight (OR = 2.60, 95%-CI: 1.41–4.81). Children with overweight (OR = 2.64, 95%-CI: 2.00, 3.49) and obesity (OR = 4.53, 95%-CI: 2.93, 7.02) were more likely to have a high handgrip strength than thin/normal weight children. Conclusions: The positive association of vitamin D with muscle strength in our study is limited to children with low and normal BMI. In children with overweight or obesity, the higher muscle strength seems to superimpose the association with vitamin D. Overall, our results indicate the importance of sufficient levels of vitamin D and offers physical activity perspectives for children with overweight and obesity.

Study registration: ISRCTN: https://doi.org/10.1186/ISRCTN62310987.

What is known
:• Studies have shown a positive association between vitamin D status and handgrip strength in older adults while studies in children and adolescents are scarce.• Conflicting results were found on whether overweight and obesity are associated with reduced or increased handgrip strength compared to normal weight.

What is new:
• The results of this large pan-European study in children and adolescents indicate that a sufficient vitamin D status is associated with better handgrip strength, particularly in participants with thinness/normal weight.• Children with overweight and obesity have a higher handgrip strength as compared to children with thinness/normal weight which seems to superimpose the positive association between vitamin D status and handgrip strength in this group.
Causal inference from observational data in neurosurgical studies: a mini-review and tutorial
Authors: Liu Mingxuan , Wang Xinru , Lee Jin Wee , Chakraborty Bibhas , Liu Nan , Volovici Victor
Published: February 2025

Background:

Establishing a causation relationship between treatments and patient outcomes is of essential importance for researchers to guide clinical decision-making with rigorous scientific evidence. Despite the fact that randomized controlled trials are widely regarded as the gold standard for identifying causal relationships, they are not without its generalizability and ethical constraints. Observational studies employing causal inference methods have emerged as a valuable alternative to exploring causal relationships.

Methods:

In this tutorial, we provide a succinct yet insightful guide about identifying causal relationships using observational studies, with a specific emphasis on research in the field of neurosurgery.

Results:

We first emphasize the importance of clearly defining causal questions and conceptualizing target trial emulation. The limitations of the classic causation framework proposed by Bradford Hill are then discussed. Following this, we introduce one of the modern frameworks of causal inference, which centers around the potential outcome framework and directed acyclic graphs. We present the obstacles presented by confounding and selection bias when attempting to establish causal relationships with observational data within this framework.

Conclusion:

To provide a comprehensive overview, we present a summary of efficient causal inference methods that can address these challenges, along with a simulation example to illustrate these techniques.
Design of profile corrections and tolerances in cylindrical gears for noise-sensitive applications in line with production efforts
Authors: Roth Laurenz , Westphal Christian , Brecher Christian
Published: February 2025

In many applications of cylindrical gearboxes, the reduction of noise from the gear mesh is an important criterion. In addition to electrified vehicle drives, gear excitations also play an important role in stationary applications such as wind turbines. When designing gearboxes, elastic surrounding structures or material combinations are increasingly being used in order to reduce mass and manufacturing costs. This has a decisive effect on the misalignment behavior of the cylindrical gears and the need for micro geometric corrections. At the same time, it must be taken into account that deviations can occur during the production of the micro geometries, which must be tolerated and have different effects on the NVH behavior.

The aim is to develop a method for the design of profile corrections for elastic environmental conditions and materials. It takes into account that the nominal design is subject to different manufacturing deviations, which have to be tolerated. This is done by means of a tolerance design mechanism that determines the best compromise between tolerance definition and manufacturing costs depending on assumptions for the relationship between manufacturing accuracy and resulting costs.

In the first step of the nominal design, the load-dependent misalignments are determined by FE-simulation. This is followed by an optimization of the micro geometric gear profile using a penetration calculation in order to optimize the excitations and improve the NVH behavior. An AI-supported substitute model of the excitation behavior of the entire gearbox is then determined. This is used to determine a suitable compromise between tolerance requirements and expected production costs using a metaheuristic optimization process. This is demonstrated using a cylindrical gearbox for electric cars. The calculation method presented enables the design of profile modifications and production tolerances using modern tools and shows further potential for noise reduction.
Real-world outcomes with avelumab + axitinib in patients with advanced renal cell carcinoma in Japan: subgroup analyses from the J-DART2 study by International Metastatic Renal Cell Carcinoma Database Consortium risk classification
Authors: Furukawa Junya , Kato Taigo , Yamasaki Toshinari , Monji Keisuke , Tanaka Toshiaki , Tsuchiya Norihiko , Miyagawa Tomoaki , Yaegashi Hiroshi , Sano Tomoyasu , Karashima Takashi , Fujita Kazutoshi , Hori Jun-ichi , Ito Takayuki , Kajita Masahiro , Tomita Yoshihiko , Shinohara Nobuo , Eto Masatoshi , Oya Mototsugu , Uemura Hirotsugu
Published: February 2025

Background

Avelumab + axitinib was approved for the treatment of advanced renal cell carcinoma (aRCC) in Japan in December 2019. We report long-term real-world subgroup analyses with first-line avelumab + axitinib in patients with aRCC by International Metastatic RCC Database Consortium (IMDC) risk classification from the J-DART2 study in Japan.

Methods

J-DART2 was a multicenter, noninterventional, retrospective study examining characteristics, treatment patterns, and outcomes in patients with aRCC who started first-line avelumab + axitinib in Japan between December 2019 and October 2022.

Results

Data from 150 patients across 19 sites were analyzed. IMDC risk was favorable in 39 patients (26.0%), intermediate (1 risk factor) in 46 (30.7%), intermediate (2 risk factors) in 36 (24.0%), and poor in 29 (19.3%). Baseline characteristics were generally consistent across IMDC risk subgroups. In subgroups with favorable, intermediate (1 risk factor), intermediate (2 risk factors), and poor risk, median progression-free survival was 31.0, 15.3, 16.4, and 8.1 months; median overall survival (OS) was not reached, but 24-month OS rates were 95.2%, 91.3%, 85.3%, and 57.6%, respectively. Objective response rates were 54.5%, 56.8%, 47.1%, and 54.2%, respectively. High-dose corticosteroid treatment for immune-related adverse events was administered in 5.1%, 8.7%, 8.3%, and 6.9% of patients, respectively.

Conclusion

Subgroup analyses from J-DART2 confirm the long-term real-world effectiveness of first-line avelumab + axitinib across IMDC risk groups in patients with aRCC in Japan. Our findings were consistent with previous analyses by IMDC risk and support the favorable benefit-risk profile of avelumab + axitinib in clinical practice in Japan.
Impact of MRI Texture Analysis on Complication Rate in MRI-Guided Liver Biopsies
Authors: Leonhardi Jakob , Niebur Maike , Höhn Anne-Kathrin , Ebel Sebastian , Struck Manuel Florian , Tautenhahn Hans-Michael , Seehofer Daniel , Zimmermann Silke , Denecke Timm , Meyer Hans-Jonas
Published: February 2025

Magnetic resonance imaging (MRI)–derived texture features are quantitative imaging parameters that may have valuable associations with clinical aspects. Their prognostic ability in patients undergoing percutaneous MRI-guided liver biopsy to identify associations with post-interventional bleeding complications and biopsy success rate has not been sufficiently investigated. The patient sample consisted 79 patients (32 females, 40.5%) with a mean age of 58.7 ± 12.4 years. Clinical parameters evaluated included comorbidities, pre-existing liver disease, known cancer diagnosis, and hemostaseological parameters. Several puncture-related parameters such as biopsy angle, distance of needle entry to capsule, and lesion were analyzed. MRI texture features of the target lesion were extracted from the planning sequence of the MRI-guided liver biopsy. Mann–Whitney U test and Fisher’s exact test were used for group comparison; multivariate regression model was used for outcome prediction. Overall, the diagnostic outcome of biopsy was malignant in 38 cases (48.1%) and benign in 32 cases (40.5%). A total of 11 patients (13.9%) had post-interventional bleeding, while nine patients (11.4%) had a negative biopsy result. Several texture features were statistically significantly different between patients with and without hemorrhage. The texture feature GrVariance (1.37 ± 0.78 vs. 0.80 ± 0.35, p = 0.007) reached the highest statistical significance. Regarding unsuccessful biopsy results, S(1,1)DifEntrp (0.80 ± 0.10 vs. 0.89 ± 0.12, p = 0.022) and S(0,4)DifEntrp (1.14 ± 0.10 vs. 1.22 ± 0.11, p = 0.021) reached statistical significance between groups. Several MRI texture features of the target lesion were associated with bleeding complications or negative biopsy after MRI-guided percutaneous liver biopsy. This could be used to identify at-risk patients at the beginning of the procedure and should be further analyzed.
On the recovery of two function-valued coefficients in the Helmholtz equation for inverse scattering problems via neural networks
Authors: Zhou Zehui
Published: February 2025

Recently, deep neural networks (DNNs) have become powerful tools for solving inverse scattering problems. However, the approximation and generalization rates of DNNs for solving these problems remain largely under-explored. In this work, we introduce two types of combined DNNs (uncompressed and compressed) to reconstruct two function-valued coefficients in the Helmholtz equation for inverse scattering problems from the scattering data at two different frequencies. An analysis of the approximation and generalization capabilities of the proposed neural networks for simulating the regularized pseudo-inverses of the linearized forward operators in direct scattering problems is provided. The results show that, with sufficient training data and parameters, the proposed neural networks can effectively approximate the inverse process with desirable generalization. Preliminary numerical results show the feasibility of the proposed neural networks for recovering two types of isotropic inhomogeneous media. Furthermore, the trained neural network is capable of reconstructing the isotropic representation of certain types of anisotropic media.