bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison Investigation on the Photocatalytic Conversion of 5‐Hydroxymethylfurfural on g‐C3N4 and S‐doped g‐C3N4: Performance and Mechanism
Authors: Zheng Anqi , Li Kewang , Duan Hui , Shi Huijie
Published: November 2024

Photocatalytic oxidation was a green and sustainable method for conversing the biomass derived platform molecule 5‐hydroxymethylfurfural (HMF) to high value‐added 2,5‐diformyfuran (DFF). In this work, both graphitized carbon nitride (g‐C3N4) and sulfur doped g‐C3N4 (S‐g‐C3N4) were fabricated, characterized and applied in the photocatalytic conversion of HMF. Accelerated separation of the photogenerated charge carriers was obtained on S‐g‐C3N4 with higher production of reactive oxygen species (ROS) including singlet oxygen (1O2) and superoxide radicals (⋅O2−), whereas relative higher HMF conversion rate and DFF selectivity were achieved on g‐C3N4. The mechanism investigation suggested that the contradictory phenomena may be caused by the stronger binding affinity of HMF on S‐g‐C3N4 compared with g‐C3N4 based on the temperature‐programmed desorption (TPD) measurement and theoretical calculation. The strong adsorption of HMF on the catalyst surface was unfavorable for desorption of the intermediates, and led to the accumulation of large number of carbon‐centered radicals. Part of these radicals may react with each other to generate polymerization products and block the active sites of the catalyst, resulted in the low conversion efficiency of HMF and DFF selectivity finally. This work provided a new sight and valuable theoretical and experimental basis for developing efficient photocatalysts for biomass conversion.
Balancing Surface Chemistry and Flake Size of MXene‐Based Electrodes for Bioelectrochemical Reactors
Authors: Kolubah Pewee. D. , Mohamed Hend Omar , Hari Ananda Rao , Ping Yue , Hassine Mohamed Ben , Dally Pia , Obaid M. , Xu Xiangming , El‐Demellawi Jehad K. , Saikaly Pascal E. , Lanza Mario , Ghaffour Noreddine , Castaño Pedro
Published: November 2024

MXenes have excellent properties as electrode materials in energy storage devices or fuel cells. In bioelectrochemical systems (for wastewater treatment and energy harvesting), MXenes can have antimicrobial characteristics in some conditions. Here, different intercalation and delamination approaches to obtain Ti3C2Tx MXene flakes with different terminal groups and lateral dimensions are comprehensively investigated. The effect of these properties on the energy harvesting performance from wastewater is then assessed. Regardless of the utilized intercalant molecules, MXene flakes obtained using soft delamination approaches are much larger (up to 10 µm) than those obtained using mechanical delamination methods (<1.5 nm), with a relatively higher content of ─O/─OH surface terminations. When employed in microbial fuel cells, electrodes made of these large MXene flakes have demonstrated a power density of over 400% higher than smaller MXene flakes, thanks to their lower charge transfer resistance (0.38 Ω). These findings highlight the crucial role of selecting appropriate intercalation and delamination methods when synthesizing MXenes for bioelectrochemical applications.
PEO‐Based Solid‐State Polymer Electrolytes for Wide‐Temperature Solid‐State Lithium Metal Batteries
Authors: Song Yunxuan , Su Meng , Xiang Hengying , Kang Junbao , Yu Wen , Peng Zhaozhao , Wang Hang , Cheng Bowen , Deng Nanping , Kang Weimin
Published: November 2024

Developing solid‐state lithium metal batteries with wide operating temperature range is important in future. Polyethylene oxide (PEO)‐based solid‐state electrolytes are extensively studied for merits including superior flexibility and low glass transition temperature. However, ideal usage temperatures for conventional PEO‐based solid‐state electrolytes are between 60 and 65 °C, and unequable temperature degrades their electrochemical performances at low and high temperatures (≤25 °C and ≥80 °C). Herein, modification methods of PEO electrolytes for low, high especially wide‐temperature applications are reviewed based on detailed analyses of mechanisms involved in its modification at different temperatures. First, shortcomings of PEO solid electrolytes due to influence of temperature are pointed out. Second, existing modification strategies are summarized in detail from three aspects of high, low especially wide temperatures, including application of PEO derivatives or chain segment modification treatment of PEO, addition of fillers, and other modification methods such as reasonable regulation of lithium salts, introduction of functional layers and addition of metal‐organic frameworks (MOFs) or covalent organic frameworks (COFs). Finally, a summary and description of PEO‐based solid electrolyte research and development trends for wide‐temperature applications are provided. The review aims to offer some guidance for the creation of PEO solid batteries with wider working temperature ranges.
Evidence of Directional Structural Superlubricity and Lévy Flights in a van der Waals Heterostructure
Authors: Le Ster Maxime , Krukowski Paweł , Rogala Maciej , Dabrowski Paweł , Lutsyk Iaroslav , Toczek Klaudia , Podlaski Krzysztof , Menteş Tefvik Onur , Genuzio Francesca , Locatelli Andrea , Bian Guang , Chiang Tai‐Chang , Brown Simon A. , Kowalczyk Paweł J.
Published: November 2024

Structural superlubricity is a special frictionless contact in which two crystals are in incommensurate arrangement such that relative in‐plane translation is associated with vanishing energy barrier crossing. So far, it has been realized in multilayer graphene and other van der Waals (2D crystals with hexagonal or triangular crystalline symmetries, leading to isotropic frictionless contacts. Directional structural superlubricity, to date unrealized in 2D systems, is possible when the reciprocal lattices of the two crystals coincide in one direction only. Here, directional structural superlubricity a α‐bismuthene/graphite van der Waals system is evidenced, manifested by spontaneous hopping of the islands over hundreds of nanometers at room temperature, resolved by low‐energy electron microscopy and supported by registry simulations. Statistical analysis of individual and collective α‐bismuthene islands populations reveal a heavy‐tailed distribution of the hopping lengths and sticking times indicative of Lévy flight dynamics, largely unobserved in condensed‐matter systems.
Pseudo‐Nanostructuring and Grain Refinement Enhance the Near‐Room‐Temperature Thermoelectric Performance in n‐type PbSe
Authors: Xie Yin , Deng Qian , Yang Yuxuan , Luo Yuange , Ou Wenxin , Zhao Zhilong , Luo Jiaxing , Wu Haijun , Ang Ran
Published: November 2024

PbSe, a promising Te‐free thermoelectric material for medium‐temperature applications, has garnered considerable attention due to its substantial thermoelectric potential and relatively low cost. However, the vast majority of research on polycrystalline PbSe thermoelectrics has focused primarily on improving its medium‐temperature performance, often neglecting the enhancement of near‐room‐temperature performance and effective module design. Here, an n‐type polycrystalline PbSe material (Cu0.01Pb0.85Ge0.15Se) is presented that exhibits a room‐temperature zT of ≈0.6 and an average zT of 0.86 from 303 to 523 K. This superior performance is realized through the incorporation of a high‐concentration Ge into n‐type Cu0.01PbSe, which induces a novel pseudo‐nanostructure and grain refinement, promoting electron‐phonon decoupling. Based on this, seven‐pair module devices are fabricated, achieving a record‐high conversion efficiency of up to 5.1% at a temperature difference of only 228 K, and an unprecedented maximum cooling temperature difference of 47.2 K when the hot‐side temperature is 350 K. The findings provide a strong foundation for advancing Te‐free polycrystalline PbSe‐based materials for thermoelectric cooling and low‐temperature power generation.
Porous Amorphous‐Crystalline Heterostructured CoNiP Nanowire Arrays for Enhanced Hydrogen Evolution Performance under Acid‐Base Conditions
Authors: Huang Linyin , Yu Yuan , Qu Yanning , Sun Dongfeng , Fan Yuhao , Qiang Pengpeng , Wei Xinyue , Su Qingmei , Hao Xiaodong , Du Gaohui , Xu Bingshe , Wang Kai
Published: November 2024

A novel porous amorphous‐crystalline heterostructured CoNiP nanowire arrays ((a‐c)CoNiP/CC) is presented. TEM observations and compositional calculations revealed ≈14.5% of the amorphous regions (a‐CoNiP) are interleaved in the crystalline regions (c‐(Co3.6Ni0.4)P4), forming massive amorphous‐crystalline heterogenous interfaces composed of the same elements. Only 38 and 64 mV overpotentials for the (a‐c)CoNiP/CC catalyst are required to reach the current density of −10 mA cm2 in acid and alkaline electrolyte, respectively, which is very close to the overpotentials (35 and 55 mV) of the commercial Pt/C HER catalyst. The theoretical calculation revealed that the (a‐c)CoNiP/CC has a completely different enhancement mechanism of HER reaction in acid‐base electrolytes. In particular, due to the natural corrosion resistance of the amorphous interface, the HER performance of this catalyst under the high current density condition is much better than that of the Pt/C catalyst either in acidic or in alkaline, suggesting its prospect for commercial applications.
Fine‐Tuning Thickness‐Dependent Molecular Aggregation for Enhanced Performance in Semitransparent Organic Photovoltaics
Authors: Zhang Hong , Xiao Linge , Zhang Yingyu , Li Shilin , Zhang Weichao , Zhang Yuan , Zhou Huiqiong
Published: November 2024

Semitransparent organic photovoltaics (ST‐OPV) exhibit tremendous potential for application in integrated photovoltaic architecture. The reduction of the ratio of wide‐bandgap donors in the active layer is crucial for enhancing both the power conversion efficiency (PCE) and the average visible light transmittance (AVT), which are key performance indicators for ST‐OPV. Herein, successful suppression of the thickness‐dependent transition from H‐aggregates to J‐aggregates in PM6 films was achieved through temperature control, significantly improving charge transport and extraction efficiency, thereby markedly enhancing the PCE of sequential processed pseudo p‐i‐n devices employing the Y6 acceptor. With ≈30% AVT maintained, the PCE increases from 6.50% to 11.10%, while the light utilization efficiency rises from 1.98% to 3.40%. Unlike previous studies primarily focused on optical coupling structure design, this research underscores the precise control of molecular aggregation behavior in the active layer material, demonstrating the innovativeness of material and structural design and offering new avenues and methodologies for the development of future semitransparent photovoltaic materials.
Identification and Structural Characterization of Novel Process‐Related Impurities Present in Oseltamivir Phosphate Drug Substance and Its Precursor
Authors: Srinivas Torati , Reddy K. V. N. Suresh , Ramu Sigilipalli , Reddy M. Kiranmai , Reddy Maddireddy Srinivasa
Published: November 2024

This article describes the identification, synthesis, and characterization of unknown impurities present in the oseltamivir phosphate drug substance and its precursor. Four unknown impurities were identified in the drug substance using high‐performance liquid chromatography analysis: Relative retention times of 1.05 and 2.50 azide impurities were found in the drug substance's precursor, and their corresponding impurities were found in the drug substance in amine form. Initially, the LC‐MS method was used to screen these impurities by identifying the mass of the impurities. Based on the impurities' mass and the drug substance's synthesis route, possible ways to form impurities were predicted. All these impurities were synthesized as predicted and characterized through infrared spectroscopy, nuclear magnetic resonance, and high‐resolution mass spectrometry techniques. It was found that these impurities are new and the synthesis method for these impurities is novel and has not been documented in the literature. The azido‐impurities found in this study are categorized as genotoxic impurities by Class 3 of the International Council for Harmonisation M7(R2) criteria, and these impurities must be regulated below certain thresholds.
A Note on Confidence Intervals for a Binomial p: Andersson–Nerman vs. Wilson
Authors: Andersson Per Gösta
Published: November 2024

Numerous approximate confidence intervals in closed form have been suggested over the years for the parameter in the binomial distribution. One of the oldest and still most advocated is the Wilson (score) interval, which in this article will be compared with the less well‐known Andersson–Nerman (henceforth AN) interval. These intervals are quite closely related, but it will be shown analytically and illustrated by examples that the coverage probability of the AN interval always equals or exceeds that of the Wilson interval, while also having uniformly larger expected length. Asymptotic expressions for the coverage probability and expected length of the AN interval are provided, using Edgeworth and Taylor expansions, respectively. The well‐behaved Wilson and AN pivots are furthermore contrasted with the problematic Wald pivot. The latter gives rise to the Wald interval, which is probably one of the best known and most used procedures altogether in the history of statistical inference. Unfortunately, this interval performs poorly, but even to this day it is to be found in many current textbooks. Therefore, it is still of relevance to search for attractive alternatives based on sound statistical principles.
MRGS‐ART: Metamorphic Relation and Group Selection Based on Adaptive Random Testing
Authors: Ying Zhihao , Towey Dave , Graham Bellotti Anthony , Quan Zhou Zhi
Published: November 2024

Metamorphic testing (MT) is effective in detecting software failures; it detects failures by examining the metamorphic relations (MRs) among source test cases (STCs), follow‐up test cases (FTCs) and their respective outputs. The STCs together with the corresponding FTCs, considered as a whole, are called metamorphic groups (MGs). MT performance relies heavily on the MRs and MGs. Previous studies have mainly focused on improving MT performance by identifying effective MRs, or through generation of MGs with high quality, but have somewhat neglected the selection of MRs and MGs from existing ones. In this paper, we address this issue by introducing a new metric for guiding the selection of effective MR‐MG pairs from a new perspective: The MR‐MG pair is chosen such that the MR makes the current MG as far away as possible from the executed MGs. We design an MR‐MG pair selection algorithm, named metamorphic relation and group selection based on adaptive random testing (MRGS‐ART), to implement our metric. The intuition behind MRGS‐ART is that we attempt to improve MT performance by achieving an even distribution of STCs and FTCs in their corresponding input domains for all the MRs used. Experimental results indicate that MRGS‐ART can enhance MT performance. We believe that this is the first comprehensive and systematic demonstration, from the perspective of both MRs and MGs, that making STCs and FTCs evenly distributed in their corresponding input domains can improve MT performance. Finally, by analysing the experimental results, we provide guidance on how to most effectively implement MRGS‐ART.
Health Risk Assessment and Heavy Metal Contamination Estimation in Date Palm Fruit Grown in Sindh, Pakistan: Multivariate Study
Authors: Bhatti Maira , Khan Humaira , Jalbani Nusrat Begum , Bhutto Shahid , Nawaz Hafiz Rub , Solangi Shakeel Haider , Ahsan Hina , Ismail Sarwat , Karim Arif , Imad Saima , Sultana Razia , Choudhry Ahsan , Tunio Nazir , Ho Soon Min
Published: November 2024

Cadmium (Cd) and lead (Pb) are commonly found in the environment due to human activities like industrialization and development. These metals are toxic and often contaminate water, food, and edible plants, leading to human exposure. This study investigates Cd and Pb levels in 68 date samples from supermarkets across various regions of Sindh, Pakistan, including 30 samples provided by companies that export date palm fruits globally. Electrothermal atomic absorption spectrometry (ETAAS) with conventional wet acid digestion (CAD) was used for metal determination. Optimization was carried out by Plackett–Burman design (PBD), central composite design (CCD), and response surface methodology (RSM). Results indicated that Cd levels in export samples ranged from 0.012 ± 0.001 to 0.061 ± 0.004, with an average value of 0.031 ± 0.002 mg/kg. Lead levels in these samples varied from 0.028 ± 0.001 to 0.079 ± 0.03, averaging 0.055 ± 0.004 mg/kg. These levels were within the safety limits. However, local market samples exhibited slightly higher Pb levels, ranging from 0.15 ± 0.01 to 0.32 ± 0.03, with an average of 0.26 ± 0.02 mg/kg, exceeding the recommended safety limits. In contrast, the Cd content in local market samples ranged from 0.12 ± 0.01 to 0.16 ± 0.02 mg/kg, remaining below the WHO/FAO. These contaminants may originate from cultivation, water, air, transportation, processing, and so forth. The method was validated by standard addition recovery test, triplicate analysis, procedure blanks, and standard reference material (SRM). The average daily intake (ADI) values for TMs, along with the hazard index (HI) and target hazard quotients (THQs) were calculated to assess potential health risks.
Endoscopic retrograde cholangiopancreatography training conditions, results from a pan‐European survey: Between vision and reality
Authors: Hamesch Karim , Cahyadi Oscar , Dimitriadis Stavros , Hollenbach Marcus , Acedo Pilar , Ayari Myriam , Dauvarte Helena , Dieninyte Egle , Domislovic Viktor , Dugic Ana , Ďuriček Martin , Elshaarawy Omar , Fennessy Anne , Geissler Mark Enrik , Gorcheva Zornitsa , Hadi Amer , Hamza Valon , Hasukić Ismar , Heinrich Henriette , Levink Iris J. M. , Kral Jan , Kunovsky Lumir , Mandorfer Mattias , Moris Maria , Nikiforova Yana , Ouaya Hassan , Pellino Gianluca , Pisani Anthea , Qejvani Odri , Sadigov Hasan , Salaga Maciej , Sidiropoulos Orestis , Simsek Cem , Sousa Paula , Stojkovic Lalosevic Milica , Straume Zane , Tepes Katja , Voiosu Andrei , Wauters Lucas , Zanetto Alberto , Schlosser Sophie , Staudacher Jonas Jaromir
Published: November 2024

Background

Endoscopic retrograde cholangiopancreatography (ERCP) still has a relatively high complication rate, underscoring the importance of high‐quality training. Despite existing guidelines, real‐world data on training conditions remain limited. This pan‐European survey aims to systematically explore the perceptions surrounding ERCP training.

Methods

A survey was distributed through the friends of United European Gastroenterology (UEG) Young Talent Group network to physicians working in a UEG member or associated states who regularly performed ERCPs.

Results

Of 1035 respondents from 35 countries, 649 were eligible for analysis: 228 trainees, 225 trainers, and 196 individuals who regularly performed ERCP but were neither trainees nor trainers. The mean age was 43 years, with 72.1% identifying as male, 27.6% as female, and 0.3% as non‐binary. The majority (80.1%) agreed that a structured training regimen is desirable. However, only 13.7% of trainees and 28.4% of trainers reported having such a structured program in their institutions. Most respondents (79.7%) supported the concept of concentrating training in centers meeting specific quality metrics, with 64.1% suggesting a threshold of 200 annual ERCPs as a prerequisite. This threshold revealed that 36.4% of trainees pursued training in lower‐volume centers performing <200 ERCPs annually. As many as 70.1% of trainees performed <50 annual ERCPs, whereas only 5.0% of trainers performed <50 ERCPs annually. A low individual trainee caseload (<50 ERCPs annually) was more common in lower‐volume centers than in higher‐volume centers (82.9% vs. 63.4%).

Conclusions

The first pan‐European survey investigating ERCP training conditions reveals strong support for structured training and the concentration of training efforts within centers meeting specific quality metrics. Furthermore, this survey exposes the low availability of structured training programs with many trainees practicing at lower‐volume centers and 71% of all trainees having little hands‐on exposure. These data should motivate to standardize ERCP training conditions further and ultimately improve patient care throughout Europe.
An Emerging Role for Ticks as Vectors of Tularaemia in Sweden
Authors: Spörndly‐Nees Ellinor , Grandi Giulio , Thorsson Elina , Gustafsson Tomas N. , Omazic Anna
Published: November 2024

Background

The zoonotic bacterium Francisella tularensis, the causative agent of tularaemia, can be transmitted to humans via multiple routes, including through contact with infected animals, contaminated water or arthropod vectors. Ticks have not previously been described as transmitting the disease in Sweden. Recently, Ixodid tick species have expanded their latitudinal and altitudinal range in Sweden to areas where the disease is endemic. Tularaemia is a cause of growing concern, spreading to new areas in Sweden and infecting hares and humans.

Objectives

To establish whether ticks could be a potential arthropod vector in the transmission of F. tularensis subsp. holarctica in Sweden.

Methods

Ticks were collected from northern Sweden and screened for F. tularensis. A follow‐up study with ticks collected from F. tularensis‐positive hares was performed. Ticks were analysed using real‐time PCR and a pathological examination was performed on the hares.

Results

F. tularensis subsp. holarctica was identified in ticks from one cat and three F. tularensis‐infected hares. Two hares had skin lesions associated with tick bites with intralesional F. tularensis bacteria.

Conclusions

F. tularensis subsp. holarctica was isolated from ticks collected from the hares and cat, the first such reports in ticks in Sweden. Identification of the bacteria at the tick bite site and the more chronic character of the skin lesions compared to those of inner organs suggest that the ticks infected the hares. The cat showed no clinical signs of disease, suggesting that its tick was indeed the vector. These new findings suggest that ticks play a role in the transmission of F. tularensis to human and animal hosts in Sweden.
Home range and core area characteristics of urban and rural coyotes and red foxes in southern Wisconsin
Authors: Farmer Morgan J. , Van Deelen Timothy R. , Storm Daniel J. , Mueller Marcus A. , Drake David
Published: November 2024

Second‐order habitat selection is influenced by a variety of factors, including individual‐ and species‐specific traits and resource requirements, as well as landscape characteristics. By comparing home range characteristics across individuals, species, and landscapes, we can draw conclusions regarding whether and how different factors influence home range selection. Our objectives were to quantify home range characteristics of VHF‐ and GPS‐collared coyotes and red foxes in urban and rural areas of southern Wisconsin, including home range size and shape, home range stability, and inter‐ and intraspecific overlap. On average, urban coyotes had smaller home ranges with apparently greater intraspecific overlap between neighboring individuals than rural coyotes. Similarly, urban red foxes had smaller home ranges with apparently greater intraspecific overlap between neighboring individuals than urban coyotes. We found no difference in home range boundary complexity or stability between urban coyotes and red foxes or between urban and rural coyotes. We did identify greater interspecific overlap between urban coyotes and red foxes than has been previously reported. Our results provide further evidence that intrinsic and extrinsic factors, such as species characteristics, resource predictability and availability, and the physical environment, influence home range selection of coyotes and red foxes.
Variation in Diet and Leafy Browse Offerings Among Colobus Monkeys (Colobus spp.) and Langurs (Trachypithecus spp.) in AZA Facilities
Authors: Plocek Maura R. , Dunham Noah T.
Published: November 2024

Providing nutritionally balanced diets is a key aspect of successful husbandry and can help support sustainable ex situ populations. This study focuses on the diets of zoo‐housed colobus monkeys (Colobus angolensis and C. guereza) and langurs (Trachypithecus cristatus and T. francoisi) across AZA institutions. We utilized survey responses from 34 institutions to (1) document the extent of dietary variation with regard to food categories and macronutrients offered, (2) assess interspecific variation in diets offered, and (3) identify important aspects of browse provisioning among institutions. A total of 95 different food items and 229 common‐name browse types were offered across institutions. Leafy greens was the only food category offered at every institution. The proportion of root and non‐root vegetables in the diet was highly variable. Nonstructural carbohydrates were the most variable macronutrient, and their concentrations were considerably higher than those food items consumed by free‐ranging colobines. Conversely, neutral detergent fiber and acid detergent fiber contents were more consistent across institutions but were notably lower than those of free‐ranging colobine food items. There were no significant interspecific differences in diets with regard to food categories or macronutrients offered. There was substantial variation in how frequently browse was offered, how it was regarded across zoos (either as diet, enrichment, or both), and whether or how it was quantified. This study provides context for future studies examining whether and how diet and macronutrient intake impact the behavior, health, and welfare of these populations.
Literature Review: Misconceptions About Phishing
Authors: Mossano Mattia , Volkamer Melanie
Published: November 2024

Phishing is a danger to both private users and businesses. Industry and academia have proposed several approaches to deal with this threat, many of which developed with a supposedly human-centric design. Yet, to our knowledge, there is no research focused on the misconceptions that users might have on phishing. This glaring gap is a problem, as previous research has shown that not engaging with the mental model of users can lead to lack of effectiveness of an approach in the real world. To address this gap, we conducted a systematic literature review starting from papers published at CHI in the last ten years, and expanding to other venues through a backward and a forward search based on the initial relevant CHI papers. We identified 15 misconceptions about phishing in 21 papers that researchers should address in their solutions to enhance the effectiveness of their approaches.
Multimode long-wave approximation for a viscoelastic coating subject to antiplane shear
Authors: Erbaş Barış , Itskov Mikhail , Kaplunov Julius , Prikazchikov Danila
Published: November 2024

A general asymptotic approach involving multimode long-wave approximations is illustrated by a 2D time-harmonic scalar problem for the dynamic antiplane shear of a viscoelastic coating. For the first time, a 1D equation of motion with the coefficients depending on frequency parameters is derived. The associated dispersion relation also seems to be a fresh development approximating its exact counterpart near the vicinities of all the cut-off frequencies. As might be expected, the developed formulation is not valid for short wavelength patterns. At the same time, as it is shown for a $$\delta $$
δ
-type loading, it proves to be robust for various scenarios dominated by long-wave response.
On Wavelet Coorbit Spaces Associated to Different Dilation Groups
Authors: Führ Hartmut , van Velthoven Jordy Timo , Voigtlaender Felix
Published: November 2024

This paper develops methods based on coarse geometry for the comparison of wavelet coorbit spaces defined by different dilation groups, with emphasis on establishing a unified approach to both irreducible and reducible quasi-regular representations. We show that the use of reducible representations is essential to include a variety of examples, such as anisotropic Besov spaces defined by general expansive matrices, in a common framework. The obtained criteria yield, among others, a simple characterization of subgroups of a dilation group yielding the same coorbit spaces. They also allow to clarify which anisotropic Besov spaces have an alternative description as coorbit spaces associated to irreducible quasi-regular representations.
Multiscale structural optimization for prescribed deformations in the nonlinear elastic regime
Authors: Murphy Ryan , Thillaithevan Dilaksan , Hewson Robert , Santer Matthew
Published: November 2024

In this paper, a multiscale structural optimization framework capable of efficiently designing two-scale structures with prescribed displacements in the nonlinear elastic regime is presented. In contrast to previous multiscale structural optimization frameworks, which are founded upon the assumptions of linear elasticity, the present framework is capable of efficiently operating within the nonlinear elastic regime. At the core of the present framework is a parameterized microscale geometry, which through the straightforward manipulation of the microscale parameters provides direct access to both positive and negative Poisson’s ratios. The microscale model is concurrently coupled to the macroscale model such that only the microscale parameter space traversed by the optimizer is resolved during the optimization procedure, leading to a significant reduction in the computational expense of analysis. To demonstrate the capability of this framework, three prescribed deformation profiles are targeted by three distinct optimization procedures. In all instances, the deformation profile is successfully targeted. To verify the accuracy of the optimized structures, high-fidelity single-scale simulations are performed. In each case, excellent agreement is noted between the high-fidelity simulations and the corresponding optimized macroscale displacement fields, with errors of less than 10%.
An enhanced guided stochastic search with repair deceleration mechanism for very high-dimensional optimization problems of steel double-layer grids
Authors: Azad Saeid Kazemzadeh , Aminbakhsh Saman , Gandomi Amir H.
Published: November 2024

Finding reasonably good solutions using a fewer number of objective function evaluations has long been recognized as a good attribute of an optimization algorithm. This becomes more important, especially when dealing with very high-dimensional optimization problems, since contemporary algorithms often need a high number of iterations to converge. Furthermore, the excessive computational effort required to handle the large number of design variables involved in the optimization of large-scale steel double-layer grids with complex configurations is perceived as the main challenge for contemporary structural optimization techniques. This paper aims to enhance the convergence properties of the standard guided stochastic search (GSS) algorithm to handle computationally expensive and very high-dimensional optimization problems of steel double-layer grids. To this end, a repair deceleration mechanism (RDM) is proposed, and its efficiency is evaluated through challenging test examples of steel double-layer grids. First, parameter tuning based on rigorous analyses of two preliminary test instances is performed. Next, the usefulness of the proposed RDM is further investigated through two very high-dimensional instances of steel double-layer grids, namely a 21,212-member free-form double-layer grid, and a 25,514-member double-layer multi-dome, with 21,212 and 25,514 design variables, respectively. The obtained numerical results indicate that the proposed RDM can significantly enhance the convergence rate of the GSS algorithm, rendering it an efficient tool to handle very high-dimensional sizing optimization problems.
Flatness constraints in the estimation of GNSS satellite antenna phase center offsets and variations
Authors: Duan Bingbing , Hugentobler Urs , Montenbruck Oliver , Steigenberger Peter , Villiger Arturo
Published: November 2024

Accurate information on satellite antenna phase center offsets (PCOs) and phase variations (PVs) is indispensable for high-precision geodetic applications. In the absence of consistent pre-flight calibrations, satellite antenna PCOs and PVs of global navigation satellite systems are commonly estimated based on observations from a global network, constraining the scale to a given reference frame. As part of this estimation, flatness and zero-mean conditions need to be applied to unambiguously separate PCOs, PVs, and constant phase ambiguities. Within this study, we analytically investigate the impact of different boresight-angle-dependent weighting functions for PV minimization, and we compare antenna models generated with different observation-based weighting schemes with those based on uniform weighting. For the case of the GPS IIR/-M and III satellites, systematic differences of 10 mm in the PVs and 65 cm in the corresponding PCOs are identified. In addition, new antenna models for the different blocks of BeiDou-3 satellites in medium Earth orbit are derived using different processing schemes. As a drawback of traditional approaches estimating PCOs and PVs consecutively in distinct steps, it is shown that different, albeit self-consistent, PCO/PV pairs may result depending on whether PCOs or PVs are estimated first. This apparent discrepancy can be attributed to potentially inconsistent weighting functions in the individual processing steps. Use of a single-step process is therefore proposed, in which a dedicated constraint for PCO-PV separation is applied in the solution of the normal equations. Finally, the impact of neglecting phase patterns in precise point positioning applications is investigated. In addition to an overall increase of the position scatter, the occurrence of systematic height biases is illustrated. While observation-based weighting in the pattern estimation can help to avoid such biases, the possible benefit depends critically on the specific elevation-dependent weighting applied in the user’s positioning model. As such, the practical advantage of such antenna models would remain limited, and uniform weighting is recommended as a lean and transparent approach for the pattern estimation of satellite antenna models from observations.
Antibacterial and anticancer activities of three novel lectin-conjugated chitosan nanoparticles
Authors: Soliman Mervat Mounir , El-Shatoury Einas Hamed , El-Araby Magda Mahmoud Ibrahim
Published: November 2024

To the best of our knowledge, this is the first attempt to synthesize, characterize, and determine the antibacterial and anticancer effects of three novel conjugates of plant lectins: phytohemagglutinin lectin (PHA), soybean agglutinin (SBA), and peanut agglutinin (PNA) with chitosan nanoparticles (CHNPs). The lectin concentration within prepared conjugates was estimated using nannodrop, and the highest concentration was 0.96 mg/ml in PHA-CHNPs. SDS-PAGE showed the molecular weights of conjugates ranged from 26.9 to 63.9 kDa. UV spectrophotometer recorded the absorbance peaks of conjugates somewhere between 200 and 230 nm. Hemagglutination analysis verified the presence of actively binding lectins. The three conjugates showed strong antibacterial activity against Gram-positive and Gram-negative bacteria compared to pure lectins and chitosan nanoparticles. The highest inhibition zone was 55.67 ± 4.04, 38.67 ± 5.51, and 37.33 ± 2.52 for PHA-CHNPs against Enterococcus faecalis, Salmonella typhimurium, and Shigella sonnei, respectively, followed by 36.3 ± 0.15 for PNA-CHNPs against Staphylococcus aureus. The lowest MIC was 1.5 µg/ml for PHA-CHNPs against Enterococcus faecalis, followed by 12 µg/ml for PNA-CHNPs and SBA-CHNPs against Salmonella typhimurium and Enterococcus faecalis, respectively. TEM microphotographs show the conjugation pattern between lectins and chitosan nanoparticles and the morphological differences between control, treated bacteria, and cancer cells. Moreover, 100 μg/ml of PHA-CHNPs affect tongue carcinoma (HNO-97), colorectal cancer (HT-29), and human melanoma (A375) cancer cell lines, reducing cell viability by 38.78 ± 1.85%, 49.88 ± 1.11%, and 66.92 ± 3.60%, respectively. This study develops three innovative conjugates of lectin chitosan nanoparticles that need to be tested as potential antibacterial and anticancer agents for medical and cancer therapy applications.

Key points

• Lectin-conjugated chitosan nanoparticles exhibit antibacterial activity.

• All conjugates are safe for oral epithelial cells and human skin fibroblasts.

• The PHA-CHNP conjugates have anticancer activity against HNO-97, HT-29, and A375.
Incorporating label uncertainty during the training of convolutional neural networks improves performance for the discrimination between certain and inconclusive cases in dopamine transporter SPECT
Authors: Kucerenko Aleksej , Buddenkotte Thomas , Apostolova Ivayla , Klutmann Susanne , Ledig Christian , Buchert Ralph
Published: November 2024

Purpose

Deep convolutional neural networks (CNN) hold promise for assisting the interpretation of dopamine transporter (DAT)-SPECT. For improved communication of uncertainty to the user it is crucial to reliably discriminate certain from inconclusive cases that might be misclassified by strict application of a predefined decision threshold on the CNN output. This study tested two methods to incorporate existing label uncertainty during the training to improve the utility of the CNN sigmoid output for this task.

Methods

Three datasets were used retrospectively: a “development” dataset (n = 1740) for CNN training, validation and testing, two independent out-of-distribution datasets (n = 640, 645) for testing only. In the development dataset, binary classification based on visual inspection was performed carefully by three well-trained readers. A ResNet-18 architecture was trained for binary classification of DAT-SPECT using either a randomly selected vote (“random vote training”, RVT), the proportion of “reduced” votes ( “average vote training”, AVT) or the majority vote (MVT) across the three readers as reference standard. Balanced accuracy was computed separately for “inconclusive” sigmoid outputs (within a predefined interval around the 0.5 decision threshold) and for “certain” (non-inconclusive) sigmoid outputs.

Results

The proportion of “inconclusive” test cases that had to be accepted to achieve a given balanced accuracy in the “certain” test case was lower with RVT and AVT than with MVT in all datasets (e.g., 1.9% and 1.2% versus 2.8% for 98% balanced accuracy in “certain” test cases from the development dataset). In addition, RVT and AVT resulted in slightly higher balanced accuracy in all test cases independent of their certainty (97.3% and 97.5% versus 97.0% in the development dataset).

Conclusion

Making between-readers-discrepancy known to CNN during the training improves the utility of their sigmoid output to discriminate certain from inconclusive cases that might be misclassified by the CNN when the predefined decision threshold is strictly applied. This does not compromise on overall accuracy.
Removing hardware from anterior approaches following acetabular fractures: a challenging yet indicated procedure
Authors: Khalifa Ahmed , Fergany Ali , Ibrahim Bahaaeldin , Farouk Osama
Published: November 2024

Purpose

To describe the indications, outcomes, and incidence of complications after hardware removal from anterior approaches following acetabular fractures.

Materials

Over ten years, 13 patients were included, complaining of pain due to late infection in nine (69.2%) and secondary osteoarthritis in four (30.8%). Fractures classification were T-type fracture (46.2%), both columns (38.5%), one transverse (7.7%), and one (7.7%) T-type with a posterior wall. The approaches utilized for hardware removal were modified Stoppa in 11 (84.6%) patients, ilioinguinal lateral (iliac) window in nine (69.2%), Pararectus in one (7.7%), ilioinguinal in one (7.7%), and Kocher-Langenbeck approach in one (7.7%)).

Results

The patients’ mean age was 37.1 ± 14.9 (21 to 65) years, and nine (69.2%) were males. Hardware removal was performed after the index surgery by a mean of 35.6 ± 20 months. The mean operative time was 143.8 ± 36 min, and the mean blood loss was 1573 ± 842 CC. The mean hospital stay was 3.2 ± 2.3 days, and all patients required blood transfusion. Four (30.8%) intraoperative complications, two (15.4%) vascular injuries, One (7.7%) urinary bladder injury, and in two (15.4%) broken screws could not be retrieved. Postoperative complications in five (38.5%): three (23.1%) had superficial wound infection, one (7.7%) had DVT, and one (7.7%) had L5 nerve root injury. After a mean follow up of 11.3 ± 4.4 (6 to 20) months, the VAS score decreased from a preoperative median of 6 (2 to 8) to a median score of 1 (0 to 6) at the last follow up. 11 (84.6%) patients described the pain as none or occasional, and eight (61.5%) were very satisfied with the results.

Conclusion

Hardware removal from the anterior approaches after acetabular fractures is demanding and carries a high complication risk. The surgeries should be performed when highly indicated, and the surgical team must be familiar with the anterior approaches.
Dual-energy CT of acute bowel ischemia—influence on diagnostic accuracy and reader confidence
Authors: Oberparleiter Moritz , Vosshenrich Jan , Breit Hanns-Christian , Kaiser Philippe , Hehenkamp Paul , Harder Dorothee , Boll Daniel T. , Zech Christoph J. , Obmann Markus M.
Published: November 2024

Objectives

This study evaluates the advantages in diagnostic accuracy, confidence, and reading time of additional dual-energy CT-derived reconstructions for assessing acute bowel ischemia.

Methods and materials

This retrospective study includes 25 patients with surgically proven acute bowel ischemia and 25 gender- and age-matched controls who underwent biphasic abdominal dual-energy CT. Two fellowship-trained abdominal radiologists and two residents evaluated all cases with and without additional dual-energy CT-derived iodine maps and virtual non-contrast images. Diagnostic confidence was rated on a 10-point Likert scale. Reading time was recorded. The inter-reader agreement was assessed using Fleiss’ kappa. Sensitivity and specificity were compared using McNemar’s test, reader confidence, and reading times with the Wilcoxon signed-rank test.

Results

For conventional images alone, the inter-reader agreement was moderate (κ = 0.58), with a sensitivity of 77% (95% CI: 67.5–84.8%) and specificity of 90% (95% CI: 82.4–95.1%). Adding dual-energy CT images, inter-reader agreement increased to substantial (κ = 0.69), sensitivity increased significantly to 89% (95% CI: 81.2–94.4%, p = 0.02), while specificity increased non-significantly to 93% (95% CI: 86.1–97.1%, p = 0.51). Diagnostic confidence increased significantly from 8 (IQR: 6–8) to 9 (IQR: 8–9) (p < 0.01). Equivalent diagnostic accuracy and confidence increases were observed for fellowship-trained and resident radiologists. A non-significant increase in mean reading time per case from 196 s to 201 s was observed (p = 0.30).

Conclusion

Additional dual-energy CT reconstructions increase diagnostic accuracy and confidence without increasing reading time when evaluating suspected acute bowel ischemia. Both experienced and resident readers benefit from dual-energy CT images.

Key Points

Question

There are too few clinical studies assessing the diagnostic accuracy of dual-energy CT (DECT) to recommend its use for evaluating suspected acute bowel ischemia.

Findings

Adding DECT-derived iodine maps and virtual-non-contrast images increase reader sensitivity and confidence while maintaining high specificity when evaluating for acute mesenteric ischemia.

Clinical relevance

Dual-energy CT should be used to investigate suspected acute bowel ischemia. Both diagnostic accuracy and confidence can be increased independent of reader experience without significantly increasing reading time.
Quantifying treatment burden: the patient burden score a study of 758 patients across three clinical urologic scenarios
Authors: Gofrit Ofer N. , Goldberg S. Nahum , Lorber Amitay , Duvdevani Mordechai , Wygoda Marc , Hidas Guy , Yutkin Vladimir , Pikarsky Liat Appelbaum
Published: November 2024

Objectives

To develop a comprehensive scale that measures the three burden types of any treatment, including expected, unexpected (complications), and need for ancillary procedures.

Methods

A panel of experts created a scale that assessed the burden of all aspects of treatment, including hospitalization, anesthesia, surgery, and follow-up. The total score is defined as the burden score (BS). BS was calculated retrospectively for patients in three clinical scenarios in urology, each with two acceptable treatment options: patients with a small renal mass (T1a) treated with either partial nephrectomy (PN, 139 patients) or percutaneous ablation (PA, 83 patients), patients with bladder cancer (stages T2-4a, N0, M0) treated with radical cystectomy (RC, 162 patients) or trimodal therapy (TMT, 88 patients), and patients with upper ureteral stones ≤ 10 mm treated with either ureteroscopy (137 patients) or extracorporeal shock-wave lithotripsy (SWL, 150 patients).

Results

Both PN and PA provided excellent oncological results (5-year recurrence-free survival ≥ 97%) and low complication rates. However, the BS of PN was more than twice that of PA (27.3 ± 7.7 vs. 12.5 ± 6.4, p < 0.01). RC and TMT showed identical 3-year disease-specific survival rates (73%), but the BS of TMT was significantly lower (53.8 ± 11.1 vs. 42.0 ± 11.6, p < 0.01). Both ureteroscopy and SWL have achieved high stone-free rates (≥ 97%) and low complication rates. However, the BS of ureteroscopy was significantly lower (7.8 ± 3 vs. 9.0 ± 3.5, p < 0.01).

Conclusion

PA treatment for small renal masses, TMT for muscle-invasive bladder cancer, and ureteroscopy for upper ureteral stones provided similar success rates to those of PN, RC, and SWL, but with significantly lower BS. This tool can assist in patient consultation when multiple treatment options are available. The concept of BS can be extended to other fields of medicine.
On-site aerodynamics using stereoscopic PIV and deep optical flow learning
Authors: Elrefaie Mohamed , Hüttig Steffen , Gladkova Mariia , Gericke Timo , Cremers Daniel , Breitsamter Christian
Published: November 2024

We introduce recurrent all-pairs field transforms for stereoscopic particle image velocimetry (RAFT-StereoPIV). Our approach leverages deep optical flow learning to analyze time-resolved and double-frame particle images from on-site measurements, particularly from the ‘Ring of Fire,’ as well as from wind tunnel measurements for fast aerodynamic analysis. A multi-fidelity dataset comprising both Reynolds-averaged Navier–Stokes (RANS) and direct numerical simulation (DNS) was used to train our model. RAFT-StereoPIV outperforms all PIV state-of-the-art deep learning models on benchmark datasets, with a 68 % error reduction on the validation dataset, Problem Class 2, and a 47 % error reduction on the unseen test dataset, Problem Class 1, demonstrating its robustness and generalizability. In comparison with the most recent works in the field of deep learning for PIV, where the main focus was the methodology development and the application was limited to either 2D flow cases or simple experimental data, we extend deep learning-based PIV for industrial applications and three-component two-dimensional (3C2D) velocity estimation. We believe that this study brings the field of experimental fluid dynamics one step closer to the long-term goal of having experimental measurement systems that can be used for fast flow field estimation.