bluuebunny/crossref_metadata_2025 huggingface dataset:
Humic Acid: A Green‐Catalyst‐Mediated Solvent‐Free Synthesis of Functionalized Diethyl(Phenyl(phenylamino)methyl)phosphonate
Authors: Datta Kumaresh , Mitra Bijeta , Ghosh Pranab
Published: August 2023

Humic acid, a high molecular weight, environment friendly biopolymer has been investigated as a catalyst for a straightforward and versatile one‐pot three‐component reaction through famous Kabachnik‐Fields reaction for the diversity‐oriented convergent synthesis of diethyl(phenyl(phenylamino)methyl)phosphonate by using aldehydes, amines and diethyl phosphite under solvent‐free reaction condition. The developed reaction protocol has successfully removed the use of hazardous solvent, toxic reagent, metal catalyst and harsh reaction condition for the synthesis of this important class of compound. The eco‐benign reaction condition, low catalyst loading, easy reaction set‐up, good yield and broad range of functional group tolerance are the key advantages of the reported protocol. Furthermore, the solvent free reaction protocol using humic acid, as a green, non‐toxic, easily available, biodegradable and easily recycled polymeric catalyst convincingly enhances the superiority of this newly developed protocol over the conventional one.
Synthesis of Arylsulfonyl Hydrazone Derivatives: Antioxidant Activity, Acetylcholinesterase Inhibition Properties, and Molecular Docking Study
Authors: Demirci Yasin , Kalay Erbay , Kara Yakup , Güler Halil İbrahim , Can Zehra , Şahin Engin
Published: August 2023

In this current paper, fifteen novel sulfonyl hydrazone derivatives have been successfully synthesized and evaluated for antioxidant activity as well as their effects on inhibitory activity toward acetylcholinesterase (AChE). By using 1H NMR, 13C NMR, FT‐IR, and high‐resolution mass spectrometry methods, the full characterization data of the novel compounds were obtained. The synthesized compounds capacity to inhibition glucosidase and exhibit antioxidant activity were tested in vitro. It was determined that compounds (E)‐4‐((2‐((4‐chlorophenyl)sulfonyl)hydrazone)methyl)‐2‐methoxyphenylfuran‐2‐carboxylate (21), (E)‐2‐methoxy‐4‐((2‐(phenylsulfonyl)hydrazone)methyl)phenylfuran‐2‐carboxylate (17) and (E)‐4‐((2‐((4‐bromophenyl)sulfonyl)hydrazone)methyl)‐2‐methoxyphenylfuran‐2‐carboxylate (25) showed good antioxidant activity. Upon examining the acetylcholinesterase inhibitory activity, it was determined that compounds (E)‐2‐methoxy‐4‐((2‐((4‐methoxyphenyl)sulfonyl) hydrazone)methyl)phenylacetate (27) (10.39 μM), (E)‐4‐((2‐((4‐chloro phenyl)sulfonyl) hydrazone)methyl)‐2‐methoxyphenylfuran‐2‐carboxylate (21) (10.81 μM), (E)‐4‐((2‐((4‐chloro phenyl)sulfonyl)hydrazone)methyl)‐2‐methoxyphenyl thiophene‐2‐carboxylate (22) (12.92 μM) and (E)‐2‐methoxy‐4‐((2‐(phenylsulfonyl)hydrazone)methyl)phenylfuran‐2‐carboxylate (17) (12.93 μM) showed potent inhibitory effects. Molecular docking simulations were used to investigate the interactions of novel sulfonyl hydrazone derivatives with human acetylcholinesterase protein. The ligands exhibited strong binding to the receptor protein with potent inhibition.
Synthesis of Novel Methylsulfonylacrylimidamide via Click Chemistry Approach, Computational Analysis and α‐ Glucosidase Inhibition Activity
Authors: Kumar Surve Santosh , Birmule Pramod R. , Sankpal Sandeep A. , Patil Sandeep B. , Kalalawe Virbhadra G. , Salunke‐Gawali Sunita , Hangirgekar Shankar
Published: August 2023

A series of Novel Methylsulfonylacrylimidamide analogs (4 a–4 h) were designed, synthesized, and screened for their α‐glucosidase inhibitory activity. The results indicated that some of the synthesized derivatives displayed inhibitory activities against α‐glucosidase with IC50 values ranging from 10.35±0.15 to 60.39±1.77 μM when compared to standard drug acarbose (IC50 832.22±2.00 μM). Among the synthesized derivatives, compounds 4 f and 4 h with a Di cyclohexyl and dioctyl substitution in the acrylimidamide displayed the most significant inhibitory activity with the IC50 value of 14.54±0.19 μM and 10.35±0.15 μM. The inhibitory action of compounds 4 f and 4 h against α‐glucosidase was studied by enzyme kinetic and molecular docking. In vitro, cytotoxicity showed that 4 f and 4 h exhibited low cytotoxicity against human cell lines. The ADME study suggested that most compounds will likely be orally active as they obeyed Lipinski's rule of five. Our studies showed that these derivatives could be considered a new class of α‐glucosidase inhibitors.
The Molecular Diversity Scope of Meldrum's Acid in Multicomponent Reactions
Authors: Ziarani Ghodsi Mohammadi , Ebrahimi Dorsa , Mohajer Fatemeh , Varma Rajender S. , Iravani Siavash
Published: August 2023

Multicomponent reactions (MCRs) have gained significant attention in the field of organic synthesis due to their ability to efficiently construct complex molecular structures in a single step. Among the reagents employed in MCRs, Meldrum's acid has emerged as a highly versatile and valuable starting material, offering a wide range of molecular diversity. This comprehensive review explores the molecular diversity scope of Meldrum's acid in various MCRs, focusing on its unique attributes and the greener aspects of its application. Meldrum's acid possesses several remarkable features that contribute to its suitability as a key component in MCRs. Its high acidity enables effective participation in a variety of chemical reactions, while its rigid structure provides stability and allows for precise control of the reaction pathways. Furthermore, the ability of Meldrum's acid to undergo both nucleophilic and electrophilic attacks makes it highly versatile in the construction of diverse molecular frameworks. Its low steric hindrance further enhances its reactivity, facilitating efficient bond formation. By surveying the literature from the last five years (2018–2022), we delve into the broad range of applications of Meldrum's acid in MCRs. The review encompasses the synthesis of various heterocyclic compounds, highlighting the significance of Meldrum's acid in achieving molecular diversity. Moreover, particular emphasis is placed on the greener aspects of utilizing Meldrum's acid, considering the growing demand for environmentally friendly synthetic approaches. This includes exploring greener solvents, milder reaction conditions, and reduced waste generation.
Cavity Size Effects on the Adsorption of CO2 on Pillar[n]arene Structures: A Density Functional Theory Study
Authors: Ho Quoc Duy , Rauls Eva
Published: August 2023

Carbon dioxide (CO2) is the main greenhouse gas that contributes to the global warming. Therefore, CO2 adsorption is very urgent in the fight to limit global warming below 1.5 degrees Celsius. In this report, the interaction between CO2 with different structures of pillar[n]arene (P[n]A) is studied by using DFTB and DFT calculations, in order to understand the effect of P[n]A (with n=4, 5, and 6) cavity sizes on CO2 adsorption. The P[n]A structures physisorb CO2 at three principally different positions called cavity‐in, top‐in, and top‐out. The adsorbed CO2‐cavity‐in at P[4]A has the highest binding energy. The adsorbed CO2 at the other positions has similar binding energies on P[4]A, P[5]A, and P[6]A, because hydrogen bonding plays a major role for the interaction at the hydroxyl group. The number of CO2 molecules that can be adsorbed at the cavity site depends on the cavity size of P[n]A. The bigger the cavity site, the larger the number of CO2 molecules that can be adsorbed before saturation is achieved. We also observed that the adsorbed CO2 molecules can interact with each other, leading to an increase of the binding energy and highlighting the promising CO2 capture capabilities of P[n]A structures.
Glycerol Acetalization in Cyclopentyl Methyl Ether with Mild Acid Catalysts
Authors: Carraro Massimo , Beccu Andrea , Carboni Silvia , Satta Giuseppe , Gaspa Silvia , De Luca Lidia , Pisano Luisa , Azzena Ugo
Published: August 2023

Reaction of glycerol with aldehydes and ketones is a strategy widely studied in literature to valorize this bioproduct. A Brønsted or Lewis acid is normally used to activate the carbonyl function and various strategies adopted to drive the equilibrium to the products. In this study ammonium salts as catalysts, and removal of water by azeotropic distillation of cyclopentyl methyl ether, permit the conversion of glycerol into acetals obtained as mixture of dioxanes and dioxolanes determined by 1H‐NMR. Under the optimized conditions, the products could be obtained in excellent yield without using excess of reactants and the solvent was recycled efficiently.
MXenes for Zinc‐Based Electrochemical Energy Storage Devices
Authors: Li Jing , Wang Chaojun , Yu Zixun , Chen Yuan , Wei Li
Published: August 2023

As an economical and safer alternative to lithium, zinc (Zn) is promising for realizing new high‐performance electrochemical energy storage devices, such as Zn‐ion batteries, Zn‐ion hybrid capacitors, and Zn‐air batteries. Well‐designed electrodes are needed to enable efficient Zn electrochemistry for energy storage. Two‐dimensional transition metal carbides and nitrides (MXenes) are emerging materials with unique electrical, mechanical, and electrochemical properties and versatile surface chemistry. They are potential material candidates for constructing high‐performance electrodes of Zn‐based energy storage devices. This review first briefly introduces the working mechanisms of the three Zn‐based energy storage devices. Then, the recent progress on the synthesis, chemical functionalization, and structural design of MXene‐based electrodes is summarized. Their performance in Zn‐based devices is analyzed to establish relations between material properties, electrode structures, and device performance. Last, several research topics are proposed to be addressed for developing practical MXene‐based electrodes for Zn‐based energy storage devices to enable their commercialization and broad adoption in the near future.
Recent Advances on Single‐Atom Catalysts for Photocatalytic CO2 Reduction
Authors: Shang Ziang , Feng Xueting , Chen Guanzhen , Qin Rong , Han Yunhu
Published: August 2023

The present energy crisis and environmental challenges may be efficiently resolved by converting carbon dioxide (CO2) into various useful carbon products. The development of more effective catalysts has been the main focus of current research on photocatalytic CO2 reduction. Due to their high atomic efficiency and superior catalytic activity, single‐atom catalysts (SACs) have attracted considerable interest in catalytic CO2 conversion. This review discusses the current research developments, obstacles, and potential of SACs for photocatalytic CO2 reduction. And further, discusses the principle of photocatalytic carbon dioxide reduction. This work has compared and analyzed the effects of support materials and active site types in SACs on photocatalytic CO2 reduction performance. This work believes that by sharing these developments, some inspiration for the rational design and development of stable and effective photocatalytic CO2 reduction catalysts based on SACs can be provided.
A Sewing Approach to the Fabrication of Eco/bioresorbable Electronics
Authors: Wu Yunyun , Rytkin Eric , Bimrose Miles , Li Shupeng , Choi Yeon Sik , Lee Geumbee , Wang Yue , Tang Lichao , Madrid Micah , Wickerson Grace , Chang Jan‐Kai , Gu Jianyu , Zhang Yamin , Liu Jiaqi , Tawfick Sameh , Huang Yonggang , King William P. , Efimov Igor R. , Rogers John A.
Published: August 2023

Eco/bioresorbable electronics represent an emerging class of technology defined by an ability to dissolve or otherwise harmlessly disappear in environmental or biological surroundings after a period of stable operation. The resulting devices provide unique capabilities as temporary biomedical implants, environmental sensors, and related systems. Recent publications report schemes to overcome challenges in fabrication that follow from the low thermostability and/or high chemical reactivity of the eco/bioresorbable constituent materials. Here, this work reports the use of high‐speed sewing machines, as the basis for a high‐throughput manufacturing technique that addresses many requirements for these applications, without the need for high temperatures or reactive solvents. Results demonstrate that a range of eco/bioresorbable metal wires and polymer threads can be embroidered into complex, user‐defined conductive patterns on eco/bioresorbable substrates. Functional electronic components, such as stretchable interconnects and antennas are possible, along with fully integrated systems. Examples of the latter include wirelessly powered light‐emitting diodes, radiofrequency identification tags, and temporary cardiac pacemakers. These advances add to a growing range of options in high‐throughput, automated fabrication of eco/bioresorbable electronics.
Density regression and uncertainty quantification with Bayesian deep noise neural networks
Authors: Zhang Daiwei , Liu Tianci , Kang Jian
Published: August 2023

Deep neural network (DNN) models have achieved state‐of‐the‐art predictive accuracy in a wide range of applications. However, it remains a challenging task to accurately quantify the uncertainty in DNN predictions, especially those of continuous outcomes. To this end, we propose the Bayesian deep noise neural network (B‐DeepNoise), which generalizes standard Bayesian DNNs by extending the random noise variable from the output layer to all hidden layers. Our model is capable of approximating highly complex predictive density functions and fully learn the possible random variation in the outcome variables. For posterior computation, we provide a closed‐form Gibbs sampling algorithm that circumvents tuning‐intensive Metropolis–Hastings methods. We establish a recursive representation of the predictive density and perform theoretical analysis on the predictive variance. Through extensive experiments, we demonstrate the superiority of B‐DeepNoise over existing methods in terms of density estimation and uncertainty quantification accuracy. A neuroimaging application is included to show our model's usefulness in scientific studies.
A comprehensive review of generative adversarial networks: Fundamentals, applications, and challenges
Authors: Megahed Mohammed , Mohammed Ammar
Published: August 2023

In machine learning, a generative model is responsible for generating new samples of data in terms of a probabilistic model. Generative adversarial network (GAN) has been widely used to generate realistic samples in different domains and outperforms its peers in the generative models family. However, producing a robust GAN model is not a trivial task because many challenges face the GAN during the training process and impact its performance, affecting the quality and diversity of the generated samples. In this article, we conduct a comprehensive review of GANs to present the fundamentals of GAN, including its components, types, and objective functions. Also, we present an overview of the evaluation matrices used to evaluate GAN models. Moreover, we list the applications of GANs and research work in various domains. Finally, we present the challenges that face GANs and highlight two significant issues, representing mode collapse and training instability, in addition to those research efforts that tackle these challenges.

This article is categorized under:

Statistical Learning and Exploratory Methods of the Data Sciences > Deep Learning

Statistical Learning and Exploratory Methods of the Data Sciences > Neural Networks
Failure Analysis of a Conveyor Belt Rail (Tripper) of Mineral
Authors: Fosca Carlos
Published: August 2023

A failure analysis of a fractured rail corresponding to a railway conveyor belt (Tripper) that operated in service for two years has been carried out. A visual inspection, chemical composition analysis, metallographic analysis, hardness and microhardness measurements were carried out on the failed piece. The rail was made of 0.89% C carbon steel and presented a decarburized area on the running surface, with strong plastic deformation due to the operation and work hardened. The metallurgical root cause is associated with the presence of pro-eutectoid ferrite and non-metallic inclusions that have been severely deformed by rolling stresses, generating a weak continuous region that nucleated rolling contact fatigue cracks (RCF) and accelerated the formation of a longitudinal crack that propagated vertically (vertical split head) as a consequence of other possible material defects.
Isolation and Characterization of Crystalline Cellulose Nanofibers (CNF’S) from Guadua Angustifolia Kunth (GAK)
Authors: Seminario Jorge Fajardo , Verdugo Carlos O. , Paltan Cesar A. , Zuluaga Robin
Published: August 2023

This work aims to isolate and characterize crystalline cellulose nanofibers from a tropical bamboo named guadua angustifolia. A nanofiber extraction methodology was developed that includes: i) a thermomechanical pretreatment by steam explosion, ii) an acid hydrolysis phase, and iii) a disintegration phase using a supermasscolloid grinder. The nanofibers were evaluated for their morphology (SEM) and (AFM), functional groups (FTIR), thermal degradation (TGA) and crystallinity index (XRD). The diameters of the nanofibers ranged from 20 to 60 nm. FTIR analysis determined an effective removal of functional groups characteristic of non-cellulosic compounds such as lignin and hemicellulose. The nanofibers showed greater thermal stability in relation to the microfibers. The crystallinity index was 75%, evidencing the effectiveness of the methodology to obtain crystalline nanocellulose.
Research into Novel Coatings on Composites and Technical Polymers, with Tailored Functionalities for the Transport and Biomedical Industries
Authors: Velasco Manrique Jorge , González Manuel Ignacio , Alonso Sastre Carlos , Cañibano Álvarez Esteban , Fernández Peña Maria Teresa
Published: August 2023

This work presents the methodology and results of the research into pre-treatments for thermal spray processes, applied to composites and technical polymers, as preparatory stage for the subsequent coating (ceramic and metallic) deposition via wire arc spray process. The research methodology includes the study of the thermal degradation of substrate materials, as well as the execution and characterization of mechanical (sand blasting), laser (surface texturing) and chemical (acid and base etching) pre-treatments. The quality of the proposed solutions is evaluated through visual inspection of the samples, optical micrography, surface roughness measurements, and mechanical adhesion testing of the coating. Finally, the selection of the most appropriate coating pre-treatment is made, considering technical and scalability criteria.
Study and Optimization of a Numerical Algorithm for Hydrodynamic Lubrication Problems with Cavitation
Authors: Gómez Molina Pedro , Carpio Huertas Jaime , Sanz Lorenzo Luis
Published: August 2023

We present a study of a method to solve numerically stationary problems of hydrodynamic lubrication with cavitation in bearings using the finite element method and the method of characteristics. The problem is based on the Elrod-Adams mathematic model for the lubricant fluid behavior. To achieve realistic pressure solutions, cavitation must be considered. However, this leads to a non-linear system of equations including a multivalued operator. To solve this problem, we use the Bermúdez-Moreno algorithm combining its ideas with a mesh intersection technique, known as supermesh, to compute certain integrals exactly, and with other strategies to improve the performance of the iterative method. We have studied the solutions, the precision in mass conservation and the speed of convergence of the method trying to improve it. Results of the simulations are presented and analyzed.
Electricity and Hydrogen Generation from Food and Vegetable Wastes – Technical and Economic Analysis
Authors: Micena Raul Pereira , de Brito Paulo Sérgio Duque , Tuna Celso Eduardo , Silveira José Luz
Published: August 2023

The city of Guaratinguetá, Brazil, produces 104 tons of MSW daily, 45.3% of which is its organic fraction, and the rest is divided between recyclable material and waste without use. This study proposes the calculation of the biogas production potential from the anaerobic digestion of the Organic Fraction of Municipal Solid Waste (OFMSW). This fraction is mainly composed of food residues, such as fruits and vegetables, as well as paper and cardboard, among others, being a compound able to be processed in a biodigester. A production potential of 3,1 Nm3 of biogas per day, or 3,6 kg/day, was calculated. An electricity generation potential of 6.3 MWh/day was calculated. Considering the use of all this electrical potential in a water electrolysis process, a production potential of 107 kg/day of electrolytic hydrogen was calculated. An economic analysis of electricity generation is carried out, resulting in a cost of electricity between 34.7 and 41.2 USD/MWh, depending on the interest rate applied. The payback of the investment in electricity generation was calculated between 3 and 4 years, considering the local electricity tariff of 74 USD/MWh.
Initial Considerations for a P2P Trading Model for Electricity Generated from Photovoltaic Solar Energy Based on Blockchain Technology
Authors: Veikka Sarkkinen , Renó Alex Alcântara , Khosravi Ali , Pabon Juan J. Garcia
Published: August 2023

The article proposed a list and discussion of the aspects that should be considered before implementing Blockchain technology in the renewable energy trade. In the proposed model, electricity is generated by solar energy and uses consumption and production data, among other things, to price electricity in a double auction, in which sellers present their prices and buyers send their bids at the same time. The use of Blockchain technology allows real-time monitoring of consumption and production, and real-time trading where third parties are not needed. It also has the potential to maximize profits from the perspective of prossumidor and minimize electricity losses. Considering Finland, it is already possible to realize that customer segments are delimited in subgroups within cities and requires the involvement of the electricity company, awareness at the state level and inversion in pilot projects.
Competitive Strategies for Renewable Energies: Brazilian Market
Authors: Corrêa Cynthia Siqueira , Maya Diego Mauricio Yepes
Published: August 2023

Renewable energy sources are sustainable alternatives for the electrical and energy development of countries. This paper analyzes the different mechanisms applicable to the Brazilian scenario. Brazil has several fronts and has direct policy instruments, such as subsidies and tax incentives, and indirect mechanisms. We analyze the need to expand existing mechanisms, implement new strategies, and improve the dissemination of existing programs to increase public awareness and pursue of a more efficient renewable energy transition. The participation of renewable sources, such as solar and wind, are gaining more and more space in the energy market in Brazil and much of this is due to incentives, such as tax and tariff rebates and long-term contracts. In 2021, the expansion of the Brazilian electric matrix was almost 1 GW (957.03 MW), according to the National Agency of Electrical Energy (ANEEL). Of this total power, 80% comes from renewable plants, from wind, hydro and solar sources.
Cavitation Analysis in Kaplan Turbines at the Yacyretá Hydropower Plant
Authors: Maldonado Liz Esquivel , Benitez Vivian González , Aguilera Fernando Arenas , Fleitas Elías Espínola , Doerksen Jovan Toews , Ratzlaff Patrik Kehler , Suárez Ferdinand Meixner , Cabañas Herminia Duarte , Duré Marcelo Subeldía , Nagasawa Jorge Kurita
Published: August 2023

The cavitation effect occurred during the operation of hydraulic machinery is a widely known and thoroughly studied phenomenon. This research work presents a case study of cavitation analysis that was conducted on the Kaplan turbines at the Yacyretá hydropower plant. This effect was observed during scheduled maintenance routines of the power generating units. These turbines belonged to the Entidad Nacional Yacyretá (EBY) [1]. The cavitation phenomenon could cause significant damage to blades and other turbine components under certain operating conditions [2].
Determination of Tool Wear in Peripheral Milling Operations Based on Acoustic Emission Signals
Authors: Alzugaray-Franz Ricardo , Diez-Cifuentes Eduardo , Leal-Muñoz Erardo , Villaverde-San José Mónica , Vizán-Idoipe Antonio
Published: August 2023

In this work, an indirect approach based on acoustic emission signals is presented to predict progressive tool wear in peripheral milling operations. Measurements of flank wear and cutting forces are considered in order to assess the performance of the method. The acoustic emission is found to be sensitive to changes of tool condition and the evolution of the wear land. The latter provides experimental evidence to support the current knowledge on tool wear estimation towards the definition of tool-life criteria based on indirect process variables.
CT-Based FEM: Assessment of the Influence of Porosity on the Mechanical Behavior and Failure of AM Components
Authors: Pascual Alejandro , Plaza Soraya , Ortega Naiara , Sendino Sara , Martínez Silvia
Published: August 2023

This work aims to present a digital-twin for prediction of the mechanical behavior and failure of additive manufacturing components, considering the characteristics of heterogeneities, mainly porosities, which appear during the manufacturing process. Therefore, the proposed methodology is based on the development of a CT-based FEM model, as well as the study of different porosity features by CT analysis and FEM modelling. Their influence on predictions is also evaluated. To this end, tensile test specimens were manufactured by means of L-PBF, according to ASTM E8/E8M. Afterwards, the analysis and digitalization of each specimen were carried out using CT, followed by FEM modelling of each one. Finally, the results obtained by the analysis were correlated with experimental tensile tests. Taking advantage of the virtual model proposed, virtual cases and hypothesis were also analyzed. Hence, the promising future of the proposed methodology is highlighted.
5-Axis Machining Center OMM Uncertainty Estimation
Authors: González Guillermo , Medina Brayan Eduwars , Ortega Naiara , Plaza Soraya , Gómez Gaizka
Published: August 2023

Nowadays, on-machine tool measurement (OMM) and coordinate measuring machine measurement (CMM) are the most common inspection methods. Although the ex-situ CMM measurements usually offers higher accuracy and reliability, OMM can inspect the workpiece without removing it from the machine tool. Therefore, it is possible to perform both in-process and post-process measurements, avoiding possible unclamping errors. However, due to the non-constant conditions in which machine tools usually operate, it is difficult to guarantee the traceability of measurements over time. For example, thermal fluctuations become a potential source of uncertainty.

This paper presents a methodology for ensuring the traceability of OMM on shop floor conditions. For this purpose, several features of a prismatic workpiece are measured on a five-axis machining center. The measurement results and its corresponding uncertainty budget are presented. For the uncertainty estimation the substitution method based on ISO 15530-3:2011 standard is used. In order to identify the impact of the different error sources on the results, a breakdown of the relative weights of the factors that may have an influence on the uncertainties is also given,
Using Artificial Intelligence to Predict Lubricated Friction in Microtextured Mechanical Contacts
Authors: Franco-Martínez Francisco , Moltó Jorge Juan García , Otero Javier Echávarri , Tanarro Enrique Chacón , Díaz-Lantada Andrés
Published: August 2023

It has been shown that surface microtexturing is useful for improving lubrication. It offers strong reductions in the friction coefficient under operation conditions which compromise the maintenance of full film lubrication. To study the influence of texturing in the reduction of the friction coefficient, an Artificial Intelligence algorithm will be used. Its performance will be optimized. Afterwards, the algorithm will be applied to a new set of textured surfaces with the objective of finding the optimal one, that is, the one capable of reducing friction under different operating conditions. The selection of the optimal texturing will be based on the Weighted Mean Value of the friction coefficient (WMPT), a metric that was specifically created for this purpose.
Autonomous Navigation for an Intelligent Sailboat - Sensailor
Authors: Fajardo-Pruna Marcelo , Sanchez-Orozco Daniela , Torres-Medina Karen , Lopez-Estrada Luis , Tutiven Christian , Vidal Yolanda
Published: August 2023

This article presents the development of an autonomous navigation system for the intelligent sailboat Sensailor. This vehicle will be equipped with a Lidar and a camera for obstacle recognition. The recollected data will allow the sailboat to register the obstacle coordinates and determine the zones for safe navigation. Based on that, the intelligent system will apply AI algorithms for path planning, in order to get the shortest safe trajectory. This way, it will be guaranteed that the Sensailor can translate from an initial to a target position while optimizing time and resources.
Measuring inflaton couplings via primordial gravitational waves
Authors: Barman Basabendu , Ghoshal Anish , Grzadkowski Bohdan , Socha Anna
Published: August 2023

Abstract

We investigate the reach of future gravitational wave (GW) detectors in probing inflaton couplings with visible sector particles that can either be bosonic or fermionic in nature. Assuming reheating takes place through perturbative quantum production from vacuum in presence of classical inflaton background field, we find that the spectral energy density of the primordial GW generated during inflation becomes sensitive to inflaton-matter coupling. We conclude, obeying bounds from Big Bang Nucleosysthesis and Cosmic Microwave Background, that, e.g., inflaton-scalar couplings of the order of ~ 𝒪(10−20) GeV fall within the sensitivity range of several proposed GW detector facilities. However, this prediction is sensitive to the size of the inflationary scale, nature of the inflaton-matter interaction and shape of the potential during reheating. Having found the time-dependent effective inflaton decay width, we also discuss its implications for dark matter (DM) production from the thermal plasma via UV freeze-in during reheating. It is shown, that one can reproduce the observed DM abundance for its mass up to several PeVs, depending on the dimension of the operator connecting DM with the thermal bath and the associated scale of the UV physics. Thus we promote primordial GW to observables sensitive to feebly coupled inflaton, which is very challenging if not impossible to test in conventional particle physics laboratories or astrophysical measurements.
Non-perturbative effects for dark sectors with QCD portals
Authors: Biondini Simone , Chowdhury Talal Ahmed , Saad Shaikh
Published: August 2023

Abstract

In this work, we consider a class of dark matter (DM) models where the DM does not directly interact with the Standard Model (SM) particles at the tree-level. Therefore, the coannihilation mechanism is crucial in achieving the correct DM relic abundance, which in turn requires the coannihilating partner to be close in mass to the actual DM particle. In our systematisation of the models’ class, the mediator and the coannihilation partner are assumed to be charged under QCD interactions. This last feature calls for a scrutiny of non-perturbative effects, namely Sommerfeld factors and bound-state formation, on the annihilations of the colored partner. Such non-perturbative effects are illustrated with an example model comprising a scalar leptoquark mediator, a Dirac vector-like fermion coannihilation partner, and a singlet DM fermion. Phenomenological features of this model, namely DM direct and indirect detection prospects, collider implications, and impact on the muon anomalous magnetic moment, are discussed.
The expanding organelle lipidomes: current knowledge and challenges
Authors: Sarmento Maria J. , Llorente Alicia , Petan Toni , Khnykin Denis , Popa Iuliana , Nikolac Perkovic Matea , Konjevod Marcela , Jaganjac Morana
Published: August 2023

Lipids in cell membranes and subcellular compartments play essential roles in numerous cellular processes, such as energy production, cell signaling and inflammation. A specific organelle lipidome is characterized by lipid synthesis and metabolism, intracellular trafficking, and lipid homeostasis in the organelle. Over the years, considerable effort has been directed to the identification of the lipid fingerprints of cellular organelles. However, these fingerprints are not fully characterized due to the large variety and structural complexity of lipids and the great variability in the abundance of different lipid species. The process becomes even more challenging when considering that the lipidome differs in health and disease contexts. This review summarizes the information available on the lipid composition of mammalian cell organelles, particularly the lipidome of the nucleus, mitochondrion, endoplasmic reticulum, Golgi apparatus, plasma membrane and organelles in the endocytic pathway. The lipid compositions of extracellular vesicles and lamellar bodies are also described. In addition, several examples of subcellular lipidome dynamics under physiological and pathological conditions are presented. Finally, challenges in mapping organelle lipidomes are discussed.
Knowledge of India as an Instrument of Nazi Politics: Ludwig Alsdorf, German Indology and Indian Anti-Colonialism
Authors: Roy Baijayanti
Published: August 2023

Ludwig Alsdorf (1904–1978) is primarily remembered as a scholar of ancient and medieval India. This paper examines a little known aspect of Alsdorf’s career: his role as an expert of modern India in Nazi Germany. Alsdorf, who was in India from 1930 to 1932, joined the NSDAP and a few of its subsidiaries after 1933. Political contacts as well as his claims of having “first-hand experience” of India secured Alsdorf writing assignments that aimed to fulfil the regime’s political objectives. In return, he gained professional advancement and the reputation of being an authority on modern India. This paper reviews Alsdorf’s trajectory within the NS state by focussing on the following aspects: the ways in which Alsdorf offered his knowledge of India to the Nazi regime; the material and symbolic resources that he received in return; the relative importance of political affiliations, professional networks and academic accomplishments for Alsdorf’s career; the “politics of the past” practised by Alsdorf and some of peers after 1945; and the (re)presentation of the “uses” of Indology in the “Third Reich” and in the Federal Republic of Germany by Alsdorf and his colleagues.
The effect of the diode laser beam power on the behaviour of the ZrC powder pre-coat and the 145Cr6 steel substrate during laser processing
Authors: Bartkowski Dariusz , Bartkowska Aneta , Jurči Peter , Kusý Martin , Przestacki Damian , Ulbrich Dariusz
Published: August 2023

The paper presents both the production method and its impact on selected properties of composite coatings reinforced with hard ZrC particles. The Fe/ZrC coatings were produced using diode laser by remelting the pre-coat in the form of paste consisting of ZrC powder and binder. Different values of laser beam power (500 W, 700 W, and 900 W) and different pre-coat thicknesses (100 µm, 150 µm, and 200 µm) were used to produce the composite coatings. During all processes, the scanning speed of laser beam was 3 m/min. Laser beam spot diameter was 1 mm. Microstructure study, microhardness tests, as well as EDS and XRD analysis were carried out. The obtained Fe/ZrC coatings were also tested for the effect of the corrosive medium in a 3.5% NaCl water solution. The effect of applied parameters on wear resistance of Fe/ZrC coatings was also studied. The tribological properties were assessed both by mass loss measurement and by scanning electron microscopy. Fe/ZrC coatings produced using the highest thickness of the pre-coat were characterised by cracks arising during production process. The very high concentration of carbides and hence high hardness of the coating produced in this way contributed to it. However, a positive effect of laser beam power increase on reduction of these cracks was observed. The coatings were characterised by very high hardness, reaching in some cases even more than 2000 HV. It was found that the most favourable properties regarding both tribology and corrosion resistance were obtained for Fe/ZrC coatings produced using 150 µm of pre-coat thickness.
Preparation of 18O-labelled azaspiracids for accurate quantitation using liquid chromatography–mass spectrometry
Authors: Wright Elliott J. , Meija Juris , McCarron Pearse , Miles Christopher O.
Published: August 2023

Azaspiracids (AZAs) are a group of polyether marine algal toxins known to accumulate in shellfish, posing a risk to human health and the seafood industry. Analysis of AZAs is typically performed using LC–MS, which can suffer from matrix effects that significantly impact the accuracy of measurement results. While the use of isotopic internal standards is an effective approach to correct for these effects, isotopically labelled standards for AZAs are not currently available. In this study, 18O-labelled AZA1, AZA2, and AZA3 were prepared by reaction with H218O under acidic conditions, and the reaction kinetics and sites of incorporation were studied using LC–HRMS/MS aided by mathematical analysis of their isotope patterns. Analysis of the isotopic incorporation in AZA1 and AZA3 indicated the presence of four exchangeable oxygen atoms. Excessive isomerization occurred during preparation of 18O-labelled AZA2, suggesting a role for the 8-methyl group in the thermodynamic stability of AZAs. Neutralized mixtures of 18O-labelled AZA1 and AZA3 were found to maintain their isotopic and isomeric integrities when stored at −20 °C and were used to develop an isotope-dilution LC–MS method which was applied to reference materials of shellfish matrices containing AZAs, demonstrating high accuracy and excellent reproducibility. Preparation of isotopically labelled compounds using the isotopic exchange method, combined with the kinetic analysis, offers a feasible way to obtain isotopically labelled internal standards for a wide variety of biomolecules to support reliable quantitation.

Graphical Abstract
Erfassung von Barrieren und Faszilitatoren zur Aufnahme einer Psychotherapie im Kontext ambulanter Kinder- und Jugendlichenpsychotherapie
Authors: Domhan Dominic , In-Albon Tina , Pfeiffer Simone
Published: August 2023

Hintergrund und Ziel

Diese Studie erweitert bisherige Ergebnisse zu Barrieren und Faszilitatoren um die Berücksichtigung der Sichtweise ambulant tätiger Kinder- und Jugendlichenpsychotherapeut*innen (KJP). Die Ergebnisse werden mit wahrgenommenen Barrieren und Faszilitatoren bei Patient*innen in ambulanter Psychotherapie verglichen und in Bezug zu bereits identifizierten Barrieren und Faszilitatoren gesetzt.

Methode

Es nahmen 61 Patient*innen im Alter von 15 bis 21 Jahren (M = 18,4, SD = ±1,6, 77 % weiblich) und 80 KJP (M = 42,3, SD = ±8,8, 81 % weiblich) aus dem ambulanten Psychotherapiesetting an der Studie teil. Barrieren und Faszilitatoren wurden in einer Onlineerhebung mittels eines explorativen deskriptiven Mixed-Methods-Designs untersucht.

Ergebnisse

Als Barrieren zur Aufnahme einer Psychotherapie wurden von Patient*innen und KJP Wahrnehmung von Hilfesuchstigma, Angst vor öffentlicher Stigmatisierung sowie Angst vor dem psychotherapeutischen Setting genannt. Patient*innen berichteten von einer stärkeren Problemleugnung als Barriere im Vergleich zu KJP. Als Faszilitatoren wurden übereinstimmend mehr Wissen über Psychotherapie, eine höhere gesellschaftliche Akzeptanz und geringere strukturelle Barrieren genannt. KJP berichteten als zusätzliche Faszilitatoren besser psychologisch geschulte Ärzt*innen und Lehrkräfte (im Sinne von Gatekeepern) sowie positive Vorerfahrungen mit Psychotherapie. Patient*innen nannten die frühzeitigere Wahrnehmung und Anerkennung des Hilfebedarfs und ein größeres Selbstbewusstsein als wichtige Faktoren zur Steigerung der Inanspruchnahme.

Diskussion

Die Ergebnisse betonen den Bedarf eines Ausbaus sowie der Dissemination von Interventionen zur Senkung von Barrieren zur Aufnahme einer Psychotherapie. Sie verdeutlichen weiterhin die Notwendigkeit, multi- und interdisziplinäre Ansätze und die Komplexität der Zusammenwirkung von Faktoren zur Steigerung des Hilfesuchverhaltens abzubilden (z. B. auf individueller, gesellschaftlicher und politischer Ebene).
A New Decomposition of the Graph Laplacian and the Binomial Structure of Mass-Action Systems
Authors: Müller Stefan
Published: August 2023

We provide a new decomposition of the Laplacian matrix (for labeled directed graphs with strongly connected components), involving an invertiblecore matrix, the vector of tree constants, and the incidence matrix of an auxiliary graph, representing an order on the vertices. Depending on the particular order, the core matrix has additional properties. Our results are graph-theoretic/algebraic in nature. As a first application, we further clarify the binomial structure of (weakly reversible) mass-action systems, arising from chemical reaction networks. Second, we extend a classical result by Horn and Jackson on the asymptotic stability of special steady states (complex-balanced equilibria). Here, the new decomposition of the graph Laplacian allows us to consider regions in the positive orthant with givenmonomial evaluation orders(and corresponding polyhedral cones in logarithmic coordinates). As it turns out, all dynamical systems are asymptotically stable that can be embedded in certainbinomial differential inclusions. In particular, this holds for complex-balanced mass-action systems, and hence, we also obtain a polyhedral-geometry proof of the classical result.
Quantitative kam Theory, with an Application to the Three-Body Problem
Authors: Pinzari Gabriella , Liu Xiang
Published: August 2023

Based on quantitative “kam theory”, we state and prove two theorems about the continuation of maximal and whiskered quasi-periodic motions to slightly perturbed systems exhibiting proper degeneracy. Next, we apply such results to prove that, in the three-body problem, there is a small set in phase space where it is possible to detect both such families of tori. We also estimate the density of such motions in proper ambient spaces. Up to our knowledge, this is the first proof of co-existence of stable and whiskered tori in a physical system.
Die Mediatisierung von Kindheit und deren Implikationen für die Medienerziehung
Authors: Roth-Ebner Caroline
Published: August 2023

Kinder wachsen heute in einer mediatisierten Lebenswelt auf. Medien sind ubiquitär verfügbar; sie dienen als Orientierungsangebote und Statussymbole und beeinflussen die kindliche Identitätsentwicklung. Inwiefern Kinder von medialen Angeboten profitieren, hängt dabei, wie zahlreiche Studien zeigen, oftmals vom Bildungsstand der Eltern ab. In Österreich besitzen die meisten Kinder elektronische Geräte und verbringen täglich etwa 2 Stunden vor Bildschirmen. Die Nutzung von sozialen Medien, insbesondere WhatsApp und YouTube, nimmt zu. Die Auswirkungen der mediatisierten Kindheit sind ambivalent. Ein und dasselbe Phänomen kann sich sowohl als Chance als auch als Risiko darstellen. Zum Beispiel können soziale Medien zur Gemeinschaftsbildung und Vernetzung dienen, andererseits aber auch destruktive Kommunikation wie Desinformation und Hate Speech fördern. Medienkompetenz wird als Schlüssel zu einer verantwortungsvollen Nutzung der Medien betrachtet. Dabei ist es vor allem wichtig, eine reflektierte Mediennutzung zu fördern, indem Erwachsene Kinder aktiv bei der Aneignung von Medien begleiten. Medienerziehung sollte stärker in Kindergärten und Schulen integriert und Eltern als zentrale Vorbilder und Miterziehende einbezogen werden.
Retrospective comparison of long-term functionality and revision rate of two different shunt valves in pediatric and adult patients
Authors: Busse Lewin-Caspar , Dubinski Daniel , Gessler Florian , Dinc Nazife , Konczalla Jürgen , Czabanka Marcus , Senft Christian , Freiman Thomas M. , Baumgarten Peter
Published: August 2023

Purpose

The most frequent therapy of hydrocephalus is implantation of ventriculoperitoneal shunts for diverting cerebrospinal into the peritoneal cavity. We compared two adjustable valves, proGAV and proGAV 2.0, for complications resulting in revision surgery.

Methods

Four hundred patients undergoing primary shunt implantation between 2014 and 2020 were analyzed for overall revision rate, 1-year revision rate, and revision-free survival observing patient age, sex, etiology of hydrocephalus, implantation site, prior diversion of cerebrospinal fluid, and cause of revision.

Results

All data were available of all 400 patients (female/male 208/192). Overall, 99 patients underwent revision surgery after primary implantation. proGAV valve was implanted in 283 patients, and proGAV 2.0 valves were implanted in 117 patients. There was no significant difference between the two shunt valves concerning revision rate (p = 0.8069), 1-year revision rate (p = 0.9077), revision-free survival (p = 0.6921), and overall survival (p = 0.3232). Regarding 1-year revision rate, we observed no significant difference between the two shunt valves in pediatric patients (40.7% vs 27.6%;p = 0.2247). Revision operation had to be performed more frequently in pediatric patients (46.6% vs 24.8%;p = 0.0093) with a significant higher number of total revisions with proGAV than proGAV 2.0 (33 of 59 implanted shunts [55.9%] vs. 8 of 29 implanted shunts [27.6%];p = 0.0110) most likely due to longer follow-up in the proGAV-group. For this reason, we clearly put emphasis on analyzing results regarding 1-year revision rate.

Conclusion

According to the target variables we analyzed, aside from lifetime revision rate in pediatric patients, there is no significant difference between the two shunt valves.
The differential impact of the DSM-5 post-traumatic stress symptoms on functional impairment in traumatized children and adolescents
Authors: Bartels Lasse , Skar Ane-Marthe Solheim , Birkeland Marianne Skogbrott , Ormhaug Silje Mørup , Berliner Lucy , Jensen Tine K.
Published: August 2023

Background

This study aims to provide a better understanding of the individual impact of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) post-traumatic stress symptoms (PTSS) on functional impairment in trauma-exposed children and adolescents. Identifying PTSS that have the most impact on functional impairment can broaden our understanding of post-trauma reactions and guide the selection of treatment components and techniques required to help patients to restore functioning following trauma exposure.

Method

Utilizing relative importance analyses, unique shared variance of each DSM-5 PTSS with functional impairment were estimated in clinical samples of 3400 Norwegian (Mage = 14.18, SDage = 2.49, rangeage = 7–17) and 747 US (Mage = 10.76, SDage = 3.10, rangeage = 7–17) children and adolescents from naturalistic settings.

Results

Negative beliefs, detachment from others, inability to experience positive emotions, and diminished interest in activities within the symptom cluster negative alterations in cognitions and mood, and the hyperarousal symptom concentration problems accounted for the largest proportions of unique variance explained in functional impairment in both samples. Further, the hyperarousal symptom irritability showed a unique high association with functional impairment in the US sample.

Conclusion

As negative beliefs, emotional numbing symptoms, concentration problems and irritability may be especially related to functional impairment in traumatized children and adolescents, monitoring and targeting these symptoms throughout therapy might be of particular importance to restore functioning as early as possible and to facilitate overall recovery.