bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Nature-Inspired Algorithms for Long-Term Digital Preservation
Authors: El-Fakdi Andres , de la Rosa Josep Lluis
Published: September 2021

Digital preservation is a research area devoted to keeping digital assets preserved and usable for many years. Out of the many approaches to digital preservation, the present research article follows a new object-centered digital preservation paradigm where digital objects share part of the responsibility for preservation: they can move, replicate, and evolve to a higher-quality format inside a digital ecosystem. In the new framework, the behavior of digital objects needs to be modeled in order to obtain the best preservation strategy. Thus, digital objects are programmed with the mission of their own long-term self-preservation, which entails being accessible and reproducible by users at any time in the future regardless of frequent technological changes due to software and hardware upgrades. Three nature-inspired computational intelligence algorithms, based on the collective behavior of decentralized and self-organized systems, were selected for the modeling approach: multipopulation genetic algorithm, ant colony optimization, and a virus-based algorithm. TiM, a simulated environment for running distributed digital ecosystems, was used to perform the experiments. The results map the relation between the models and the expected object diversity obtained in short- and mid-term digital preservation scenarios. Comparing the results, the best performance corresponded to the multipopulation genetic algorithm. The article aims to be a first step in the digital self-preservation field. Building nature-inspired model behaviors is a good approach and opens the door to future tests with other AI-based methods.
A DANP-Based NDEA-MOP Approach to Evaluating the Patent Commercialization Performance of Industry–Academic Collaborations
Authors: Huang Chi-Yo , Yang Min-Jen , Li Jeen-Fong , Chen Hueiling
Published: September 2021

The industry–academic collaboration (IAC) in developed and developing countries enables these economies to gain momentum in continuous innovation and, thus, economic growth. Patent commercialization is one major channel of knowledge flow in IAC. However, very few studies consider the flow of knowledge between industrial firms and universities. Moreover, ways that the patent commercialization performance of IACs can be evaluated are rarely discussed. Therefore, defining an analytic framework to evaluate the performance of IAC from the aspect of patent commercialization is critical. Traditionally, data envelopment analysis (DEA) models have widely been adopted in performance evaluation. However, traditional DEA models cannot accurately evaluate the performance of IACs with complex university–industry interconnections, the internal linkages, or linking activities of knowledge-flow within the decision-making units (DMUs), i.e., the IACs. In order to solve the abovementioned problems, this study defines a multiple objective programming (MOP)-based network DEA (NDEA), with weighting derived from the decision-making trial and evaluation laboratory (DEMATEL)-based analytic network process (ANP), or the DANP. The proposed analytic framework can evaluate the efficiency of decision-making units (DMUs) with a network structure (e.g., supply chains, strategic alliances, etc.) based on the weights that have been derived, based on experts’ opinions. An empirical study based on the performance of the patent commercialization of Taiwanese IACs was used to demonstrate the feasibility of the proposed framework. The results of the empirical research can serve as a basis for improving the performance of IAC.
Coupled Fixed Point Results in Banach Spaces with Applications
Authors: Zada Mian Bahadur , Sarwar Muhammad , Abdeljawad Thabet , Mukheimer Aiman
Published: September 2021

The aim of this work is to discuss the existence of solutions to the system of fractional variable order hybrid differential equations. For this reason, we establish coupled fixed point results in Banach spaces.
A Set of New Stable, Explicit, Second Order Schemes for the Non-Stationary Heat Conduction Equation
Authors: Kovács Endre , Nagy Ádám , Saleh Mahmoud
Published: September 2021

This paper introduces a set of new fully explicit numerical algorithms to solve the spatially discretized heat or diffusion equation. After discretizing the space and the time variables according to conventional finite difference methods, these new methods do not approximate the time derivatives by finite differences, but use a combined two-stage constant-neighbour approximation to decouple the ordinary differential equations and solve them analytically. In the final expression for the new values of the variable, the time step size appears not in polynomial or rational, but in exponential form with negative coefficients, which can guarantee stability. The two-stage scheme contains a free parameter p and we analytically prove that the convergence is second order in the time step size for all values of p and the algorithm is unconditionally stable if p is at least 0.5, not only for the linear heat equation, but for the nonlinear Fisher’s equation as well. We compare the performance of the new methods with analytical and numerical solutions. The results suggest that the new algorithms can be significantly faster than the widely used explicit or implicit methods, particularly in the case of extremely large stiff systems.
Linear Complexity and Trace Representation of New Ding Generalized Cyclotomic Sequences with Period pq and Order Two
Authors: Ma Jiang , Zhao Wei , Jia Yanguo , Shen Xiumin , Jiang Haiyang
Published: September 2021

Linear complexity is an important property to measure the unpredictability of pseudo-random sequences. Trace representation is helpful for analyzing cryptography properties of pseudo-random sequences. In this paper, a class of new Ding generalized cyclotomic binary sequences of order two with period pq is constructed based on the new segmentation of Ding Helleseth generalized cyclotomy. Firstly, the linear complexity and minimal polynomial of the sequences are investigated. Then, their trace representation is given. It is proved that the sequences have larger linear complexity and can resist the attack of the Berlekamp–Massey algorithm. This paper also confirms that generalized cyclotomic sequences with good randomness may be obtained by modifying the characteristic set of generalized cyclotomy.
Multiple-Solution Tasks in Pre-Service Teachers Course on Combinatorics
Authors: Semanišinová Ingrid
Published: September 2021

In the paper, we present a study devoted to the utilization of multiple-solution tasks (MSTs) in combinatorics as a part of a pre-service teachers course on didactics of mathematics from the view of the mathematics teachers’ specialized knowledge (MTSK) theoretical framework. The study was carried out over the standard course of a summer semester in 2021. The course was attended by 13 pre-service teachers (PSTs). It was carried out online, due to COVID-19 restrictions. Ten combinatorial multiple-solution tasks were assigned to the PSTs. Analyzing pre-service teachers solutions to these tasks, we sought the description and better understanding of the combinatorial knowledge of the topic from the perspective of MSTK. The results revealed some critical aspects of mathematical knowledge in combinatorics that pre-service teachers education should focus on.
Alternative Thresholding Technique for Image Segmentation Based on Cuckoo Search and Generalized Gaussians
Authors: Munoz-Minjares Jorge , Vite-Chavez Osbaldo , Flores-Troncoso Jorge , Cruz-Duarte Jorge M.
Published: September 2021

Object segmentation is a widely studied topic in digital image processing, as to it can be used for countless applications in several fields. This process is traditionally achieved by computing an optimal threshold from the image intensity histogram. Several algorithms have been proposed to find this threshold based on different statistical principles. However, the results generated via these algorithms contradict one another due to the many variables that can disturb an image. An accepted strategy to achieve the optimal histogram threshold, to distinguish between the object and the background, is to estimate two data distributions and find their intersection. This work proposes a strategy based on the Cuckoo Search Algorithm (CSA) and the Generalized Gaussian (GG) distribution to assess the optimal threshold. To test this methodology, we carried out several experiments in synthetic and practical scenarios and compared our results against other well-known algorithms from the literature. These practical cases comprise a medical image database and our own generated database. The results in a simulated environment show an evident advantage of the proposed strategy against other algorithms. In a real environment, this ranks among the best algorithms, making it a reliable alternative.
Voxel-Based 3D Object Reconstruction from Single 2D Image Using Variational Autoencoders
Authors: Tahir Rohan , Sargano Allah Bux , Habib Zulfiqar
Published: September 2021

In recent years, learning-based approaches for 3D reconstruction have gained much popularity due to their encouraging results. However, unlike 2D images, 3D cannot be represented in its canonical form to make it computationally lean and memory-efficient. Moreover, the generation of a 3D model directly from a single 2D image is even more challenging due to the limited details available from the image for 3D reconstruction. Existing learning-based techniques still lack the desired resolution, efficiency, and smoothness of the 3D models required for many practical applications. In this paper, we propose voxel-based 3D object reconstruction (V3DOR) from a single 2D image for better accuracy, one using autoencoders (AE) and another using variational autoencoders (VAE). The encoder part of both models is used to learn suitable compressed latent representation from a single 2D image, and a decoder generates a corresponding 3D model. Our contribution is twofold. First, to the best of the authors’ knowledge, it is the first time that variational autoencoders (VAE) have been employed for the 3D reconstruction problem. Second, the proposed models extract a discriminative set of features and generate a smoother and high-resolution 3D model. To evaluate the efficacy of the proposed method, experiments have been conducted on a benchmark ShapeNet data set. The results confirm that the proposed method outperforms state-of-the-art methods.
Formal Model of IDS Based on BDI Logic
Authors: Perháč Ján , Novitzká Valerie , Steingartner William , Bilanová Zuzana
Published: September 2021

Computer network security is an important aspect of computer science. Many researchers are trying to increase security using different methods, technologies, or tools. One of the most common practices is the deployment of an Intrusion Detection System (IDS). The current state of IDS brings only passive protection from network intrusions, i.e., IDS can only detect possible intrusions. Due to that, the manual intervention of an administrator is needed. In our paper, we present a logical model of an active IDS based on category theory, coalgebras, linear logic, and Belief–Desire–Intention (BDI) logic. Such an IDS can not only detect intrusions but also autonomously react to them according to a defined security policy. We demonstrate our approach on a motivating example with real network intrusions.
New Results on the Aggregation of Norms
Authors: Pedraza Tatiana , Rodríguez-López Jesús
Published: September 2021

It is a natural question if a Cartesian product of objects produces an object of the same type. For example, it is well known that a countable Cartesian product of metrizable topological spaces is metrizable. Related to this question, Borsík and Doboš characterized those functions that allow obtaining a metric in the Cartesian product of metric spaces by means of the aggregation of the metrics of each factor space. This question was also studied for norms by Herburt and Moszyńska. This aggregation procedure can be modified in order to construct a metric or a norm on a certain set by means of a family of metrics or norms, respectively. In this paper, we characterize the functions that allow merging an arbitrary collection of (asymmetric) norms defined over a vector space into a single norm (aggregation on sets). We see that these functions are different from those that allow the construction of a norm in a Cartesian product (aggregation on products). Moreover, we study a related topological problem that was considered in the context of metric spaces by Borsík and Doboš. Concretely, we analyze under which conditions the aggregated norm is compatible with the product topology or the supremum topology in each case.
Equivalence of Certain Iteration Processes Obtained by Two New Classes of Operators
Authors: Abbas Mujahid , Anjum Rizwan , Berinde Vasile
Published: September 2021

The aim of this paper is two fold: the first is to define two new classes of mappings and show the existence and iterative approximation of their fixed points; the second is to show that the Ishikawa, Mann, and Krasnoselskij iteration methods defined for such classes of mappings are equivalent. An application of the main results to solve split feasibility and variational inequality problems are also given.
Network Analysis Based on Important Node Selection and Community Detection
Authors: Mester Attila , Pop Andrei , Mursa Bogdan-Eduard-Mădălin , Greblă Horea , Dioşan Laura , Chira Camelia
Published: September 2021

The stability and robustness of a complex network can be significantly improved by determining important nodes and by analyzing their tendency to group into clusters. Several centrality measures for evaluating the importance of a node in a complex network exist in the literature, each one focusing on a different perspective. Community detection algorithms can be used to determine clusters of nodes based on the network structure. This paper shows by empirical means that node importance can be evaluated by a dual perspective—by combining the traditional centrality measures regarding the whole network as one unit, and by analyzing the node clusters yielded by community detection. Not only do these approaches offer overlapping results but also complementary information regarding the top important nodes. To confirm this mechanism, we performed experiments for synthetic and real-world networks and the results indicate the interesting relation between important nodes on community and network level.
Hybrid of the Lee-Carter Model with Maximum Overlap Discrete Wavelet Transform Filters in Forecasting Mortality Rates
Authors: Yaacob Nurul Aityqah , Jaber Jamil J. , Pathmanathan Dharini , Alwadi Sadam , Mohamed Ibrahim
Published: September 2021

This study implements various, maximum overlap, discrete wavelet transform filters to model and forecast the time-dependent mortality index of the Lee-Carter model. The choice of appropriate wavelet filters is essential in effectively capturing the dynamics in a period. This cannot be accomplished by using the ARIMA model alone. In this paper, the ARIMA model is enhanced with the integration of various maximal overlap discrete wavelet transform filters such as the least asymmetric, best-localized, and Coiflet filters. These models are then applied to the mortality data of Australia, England, France, Japan, and USA. The accuracy of the projecting log of death rates of the MODWT-ARIMA model with the aforementioned wavelet filters are assessed using mean absolute error, mean absolute percentage error, and mean absolute scaled error. The MODWT-ARIMA (5,1,0) model with the BL14 filter gives the best fit to the log of death rates data for males, females, and total population, for all five countries studied. Implementing the MODWT leads towards improvement in the performance of the standard framework of the LC model in forecasting mortality rates.
Investigation of the Fractional Strongly Singular Thermostat Model via Fixed Point Techniques
Authors: Kaabar Mohammed K. A. , Shabibi Mehdi , Alzabut Jehad , Etemad Sina , Sudsutad Weerawat , Martínez Francisco , Rezapour Shahram
Published: September 2021

Our main purpose in this paper is to prove the existence of solutions for the fractional strongly singular thermostat model under some generalized boundary conditions. In this way, we use some recent nonlinear fixed-point techniques involving α-ψ-contractions and α-admissible maps. Further, we establish the similar results for the hybrid version of the given fractional strongly singular thermostat control model. Some examples are studied to illustrate the consistency of our results.
A Coupling between Integral Equations and On-Surface Radiation Conditions for Diffraction Problems by Non Convex Scatterers
Authors: Alzahrani Saleh Mousa , Antoine Xavier , Chniti Chokri
Published: September 2021

The aim of this paper is to introduce an orignal coupling procedure between surface integral equation formulations and on-surface radiation condition (OSRC) methods for solving two-dimensional scattering problems for non convex structures. The key point is that the use of the OSRC introduces a sparse block in the surface operator representation of the wave field while the integral part leads to an improved accuracy of the OSRC method in the non convex part of the scattering structure. The procedure is given for both the Dirichlet and Neumann scattering problems. Some numerical simulations show the improvement induced by the coupling method.
Characterization of Traveling Waves Solutions to an Heterogeneous Diffusion Coupled System with Weak Advection
Authors: Díaz Palencia José Luis
Published: September 2021

The aim of this work is to characterize Traveling Waves (TW) solutions for a coupled system with KPP-Fisher nonlinearity and weak advection. The heterogeneous diffusion introduces certain instabilities in the TW heteroclinic connections that are explored. In addition, a weak advection reflects the existence of a critical combined TW speed for which solutions are purely monotone. This study follows purely analytical techniques together with numerical exercises used to validate or extent the contents of the analytical principles. The main concepts treated are related to positivity conditions, TW propagation speed and homotopy representations to characterize the TW asymptotic behaviour.
Quasi-Deterministic Processes with Monotonic Trajectories and Unsupervised Machine Learning
Authors: Orekhov Andrey V.
Published: September 2021

This paper aims to consider approximation-estimation tests for decision-making by machine-learning methods, and integral-estimation tests are defined, which is a generalization for the continuous case. Approximation-estimation tests are measurable sampling functions (statistics) that estimate the approximation error of monotonically increasing number sequences in different classes of functions. These tests make it possible to determine the Markov moments of a qualitative change in the increase in such sequences, from linear to nonlinear type. If these sequences are trajectories of discrete quasi-deterministic random processes, then moments of change in the nature of their growth and qualitative change in the process match up. For example, in cluster analysis, approximation-estimation tests are a formal generalization of the “elbow method” heuristic. In solid mechanics, they can be used to determine the proportionality limit for the stress strain curve (boundaries of application of Hooke’s law). In molecular biology methods, approximation-estimation tests make it possible to determine the beginning of the exponential phase and the transition to the plateau phase for the curves of fluorescence accumulation of the real-time polymerase chain reaction, etc.
Antibacterial Bicyclic Fatty Acids from a Korean Colonial Tunicate Didemnum sp.
Authors: Kim Hiyoung , Lee Tae Gu , Yang Inho , Wang Weihong , Chin Jungwook , Lee Jusung , Rho Boon Jo , Choi Hyukjae , Nam Sang-Jip , Hahn Dongyup , Kang Heonjoong
Published: September 2021

Five new bicyclic carboxylic acids were obtained by antibacterial activity-guided isolation from a Korean colonial tunicate Didemnum sp. Their structures were elucidated by the interpretation of NMR, MS and CD spectroscopic data. They all belong to the class of aplidic acids. Three of them were amide derivatives (1–3), and the other two were dicarboxylic derivatives (4 and 5). The absolute configurations were determined by a bisignate pattern of CD spectroscopy, which revealed that the absolute configurations of amides were opposite to those of dicarboxylates at every stereogenic centers. Compound 2 exhibited the most potent antibacterial activity (MIC, 2 μg/mL).
Isolation of Sesquiterpenoids and Steroids from the Soft Coral Sinularia brassica and Determination of Their Absolute Configuration
Authors: Pham Giang Nam , Kang Da Yeun , Kim Min Ju , Han Se Jong , Lee Jun Hyuck , Na MinKyun
Published: September 2021

Two undescribed rearranged cadinane-type sesquiterpenoids (1–2), named sinulaketol A-B, together with one new chlorinated steroid (3), one new gorgosterol (4), one known sesquiterpene (5), one known dibromoditerpene (6) and two known polyhydroxylated steroids (7–8) were isolated from the soft coral Sinularia brassica. The structures of these compounds were established by extensive spectroscopic analysis, including HRESIMS, 1D, and 2D NMR spectroscopy. Their absolute configurations were also determined by the ECD calculations and DP4+ probability analysis. Antileishmanial activity of compounds 1–8 was evaluated in vitro against the amastigote forms of Leishmania donovani, in which compounds 3, 6, and 7 inhibited the growth of L. donovani by 58.7, 74.3, 54.7%, respectively, at a concentration of 50 μM. Antimicrobial effect of the isolated compounds were also evaluated against Candida albicans, Staphylococcus aureus, and Escherichia coli. Compound 6, a brominated diterpene, exhibited antimicrobial effect against S. aureus.
Suicidality and Its Relation with Physical and Mental Conditions: Results from a Cross-Sectional Study of the Nationwide Primary Care Population Sample in Latvia
Authors: Renemane Lubova , Kivite-Urtane Anda , Rancans Elmars
Published: September 2021

Background and Objectives: Physical and mental conditions are important risk factors for suicidality. However, there is no clear understanding of these relationships and the effect of co-occurrence on suicidality. We aimed to investigate the associations between current suicidality and mental disorders, physical conditions, and health-related factors in the nationwide primary care population in Latvia. Materials and Methods: A cross-sectional study was performed within the framework of the National Research Program BIOMEDICINE 2014–2017 at 24 primary care settings across Latvia in 2015. Adult patients were evaluated over one week at each facility. Socio-demographic variables, physical condition, and health-related factors were assessed on-site by trained psychiatrists. Mental disorders and suicidality were determined using the Mini International Neuropsychiatric Interview, and assessments were conducted over the telephone within two weeks after the visit to the general practitioner. Results: Of the 1485 cases, 18.6% reported suicidality. Only current depression, any anxiety disorder, any alcohol use disorder, and physical-mental multimorbidity were significantly associated with suicidality in the multivariate logistic regression analysis. Gastrointestinal diseases were associated with current depression alone (odds ratio (OR) 10.36; 95% confidence interval (CI) 2.34–45.76) and comorbid depression with any anxiety disorder (OR 7.55; 95% CI 2.15–26.49) among persons with current suicidality. Conclusions: Screening for depression, anxiety, and alcohol use disorders regularly among patients with physical illness may be important to help recognise suicidality in primary care that could improve the quality of life of patients and prevent suicides.
The Influence of Serum Uric Acid Level on Non-Motor Symptoms Occurrence and Severity in Patients with Idiopathic Parkinson’s Disease and Atypical Parkinsonisms—A Systematic Review
Authors: Grażyńska Anna , Adamczewska Klaudia , Antoniuk Sofija , Bień Martyna , Toś Mateusz , Kufel Jakub , Urbaś Weronika , Siuda Joanna
Published: September 2021

Background and Objectives: A growing number of studies correlated higher levels of serum uric acid (UA) with both: lower risk of Parkinson’s Disease (PD) occurrence and slower progression of the disease. Similar conclusions were made where studies correlated UA with atypical Parkinsonisms (AP) progression. A few researchers have studied the issue of the influence of serum UA on the occurrence of non-motor symptoms (NMS) in PD and AP. Our systematic review is the first review completely dedicated to this matter. Materials and Methods: A comprehensive evaluation of the literature was performed to review the relationship between UA and NMS in PD and AP. The systematic review was conducted according to PRISMA Statement guidelines. The following databases were searched starting in April 2021: MEDLINE via PubMed, Embase, and Scopus. During the research, the following filters were used: >2010, articles in English, concerning humans. The study was not registered and received no external funding. Results: Seven articles meeting all inclusion criteria were included in this study. Collectively, data on 1104 patients were analyzed. A correlation between serum UA concentration and a few NMS types has been provided by the analyzed studies. In four papers, sleep disorders and fatigue were related to UA for both advanced and early PD. Other commonly appearing NMS domains were Attention/memory (4 studies), Depression/anxiety (3 studies), Cardiovascular (3 studies), Gastrointestinal (1 study), Perceptual (1 study), and Miscellaneous (1 study). For AP, no significant correlation between UA and worsening of NMS has been found. Conclusions: Based on the analyzed studies, a correlation between serum UA level and the occurrence and worsening of NMS in PD and APs cannot be definitively determined. Large-scale studies with a more diverse patient population and with more accurate methods of NMS assessment in Parkinsonism are needed.
ABCA1 rs1883025 and CYP4F2 rs2108622 Gene Polymorphism Association with Age-Related Macular Degeneration and Anti-VEGF Treatment
Authors: Mockute Ruta , Vilkeviciute Alvita , Balciuniene Vilma Jurate , Zemaitiene Reda , Liutkeviciene Rasa
Published: September 2021

Background and Objectives: The age-related macular degeneration (AMD) pathophysiology is multifactorial, as it consists of interactions between aging, genetic, and environmental factors. We aimed to determine a relationship between AMD and the genes controlling lipid metabolism, and to assess its association with treatment results. The purpose was to find the ABCA1 rs1883025 and CYP4F2 rs2108622 gene polymorphisms in patients with exudative AMD (eAMD) treated with anti-VEGF. Materials and Methods: The study enroled 104 patients with eAMD and 201 healthy persons in a control group. The genotyping of rs1883025 and rs2108622 was performed using the RT-PCR method. The best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were measured before anti-VEGF therapy, then at three and six months during the therapy, using optical coherence tomography (OCT). The patients were grouped to responders and non-responders according to the changes in BCVA and CRT. Results: The T allele at rs1883025 was more frequent in non-responder eAMD patients compared to responder eAMD patients (41.7% vs. 21.1%; p = 0.009). The analysis of rs2108622 gene polymorphism did not reveal any differences in the distribution of C/C, C/T, and T/T genotypes between the eAMD group and the control group (56.35%, 39.78%, and 3.87% in the eAMD group and 53.33%, 39.05% and 7.62% in the control group, respectively, p = 0.286). The comparison of CRT and BCVA between the rs2108622 genotypes revealed statistically significant differences: CRT was thicker for the CC carriers than for those with CT and TT genotypes (p = 0.030). Conclusion: The rs1883025 T allele was found to play a more significant role in non-responder eAMD patients compared to responder eAMD patients. The rs2108622 genotypes revealed statistically significant differences: CRT was thicker for the CC carriers than for those with CT and TT genotypes.
EEG-Based Evidence of Mirror Neuron Activity from App-Mediated Stroke Patient Observation
Authors: Kim Jin-Cheol , Lee Hyun-Min
Published: September 2021

Background and Objectives: The mirror neuron system in the sensorimotor region of the cerebral cortex is equally activated during both action observation and execution. Action observation training mimics the functioning of the mirror neuron system, requiring patients to watch and imitate the actions necessary to perform activities of daily living. StrokeCare is a user-friendly application based on the principles of action observation training, designed to assist people recovering from stroke. Therefore, when observing the daily life behavior provided in the StrokeCare app, whether the MNS is activated and mu inhibition appears. Materials and Methods: We performed electroencephalography (EEG) on 24 patients with chronic stroke (infarction: 11, hemorrhage: 13) during tasks closely related to daily activities, such as dressing, undressing, and walking. The StrokeCare app provided action videos for patients to watch. Landscape imagery observation facilitated comparison among tasks. We analyzed the mu rhythm from the C3, CZ, and C4 regions and calculated the mean log ratios for comparison of mu suppression values. Results: The EEG mu power log ratios were significantly suppressed during action observation in dressing, undressing, walking, and landscape conditions, in decreasing order. However, there were no significant activity differences in the C3, C4 and CZ regions. The dressing task showed maximum suppression after a color spectrum was used to map the relative power values of the mu rhythm for each task. Conclusions: These findings reveal that the human mirror neuron system was more strongly activated during observation of actions closely related to daily life activities than landscape images.
Effect of Direct Fluorination on the Transport Properties and Swelling of Polymeric Materials: A Review
Authors: Belov Nikolay A. , Pashkevich Dmitrii S. , Alentiev Alexandre Yu , Tressaud Alain
Published: September 2021

Fluorine-containing polymers occupy a peculiar niche among conventional polymers due to the unique combination of physicochemical properties. Direct surface fluorination of the polymeric materials is one of the approaches for the introduction of fluorine into the chemical structure that allows one to implement advantages of fluorinated polymers in a thin layer. Current review considers the influence of the surface interaction of the polymeric materials and membranes with elemental fluorine on gas, vapor and liquid transport as well as swelling and related phenomena. The increase in direct fluorination duration and concentration of fluorine in the fluorination mixture is shown to result mostly in a reduction of all penetrants permeability to a different extent, whereas selectivity of the selected gas pairs (He-H2, H2-CH4, He-CH4, CO2-CH4, O2-N2, etc.) increases. Separation parameters for the treated polymeric films approach Robeson’s upper bounds or overcome them. The most promising results were obtained for highly permeable polymer, polytrimethylsilylpropyne (PTMSP). The surface fluorination of rubbers in printing equipment leads to an improved chemical resistance of the materials towards organic solvents, moisturizing solutions and reduce diffusion of plasticizers, photosensitizers and other components of the polymeric blends. The direct fluorination technique can be also considered one of the approaches of fabrication of fuel cell membranes from non-fluorinated polymeric precursors that improves their methanol permeability, proton conductivity and oxidative stability.
Ceramic Processing of Silicon Carbide Membranes with the Aid of Aluminum Nitrate Nonahydrate: Preparation, Characterization, and Performance
Authors: Eray Esra , Candelario Victor Manuel , Boffa Vittorio
Published: September 2021

The development of a low-cost and environmentally-friendly procedure for the fabrication of silicon carbide (SiC) membranes while achieving good membrane performance is an important goal, but still a big challenge. To address this challenge, herein, a colloidal coating suspension of sub-micron SiC powders was prepared in aqueous media by employing aluminum nitrate nonahydrate as a sintering additive and was used for the deposition of a novel SiC membrane layer onto a SiC tubular support by dip-coating. The sintering temperature influence on the structural morphology was studied. Adding aluminum nitrate nonahydrate reduced the sintering temperature of the as-prepared membrane compared to conventional SiC membrane synthesis. Surface morphology, pore size distribution, crystalline structure, and chemical and mechanical stability of the membrane were characterized. The membrane showed excellent corrosion resistance in acidic and basic medium for 30 days with no significant changes in membrane properties. The pure water permeance of the membrane was measured as 2252 L h−1 m−2 bar−1. Lastly, the final membrane with 0.35 µm mean pore size showed high removal of oil droplets (99.7%) in emulsified oil-in-water with outstanding permeability. Hence, the new SiC membrane is promising for several industrial applications in the field of wastewater treatment.
High-Level Expression of Palmitoylated MPP1 Recombinant Protein in Mammalian Cells
Authors: Chytła Agnieszka , Gajdzik-Nowak Weronika , Biernatowska Agnieszka , Sikorski Aleksander F. , Czogalla Aleksander
Published: September 2021

Our recent studies have pointed to an important role of the MAGUK family member, MPP1, as a crucial molecule interacting with flotillins and involved in the lateral organization of the erythroid plasma membrane. The palmitoylation of MPP1 seems to be an important element in this process; however, studies on the direct effect of palmitoylation on protein–protein or protein–membrane interactions in vitro are still challenging due to the difficulties in obtaining functional post-translationally modified recombinant proteins and the lack of comprehensive protocols for the purification of palmitoylated proteins. In this work, we present an optimized approach for the high-yield overexpression and purification of palmitoylated recombinant MPP1 protein in mammalian HEK-293F cells. The presented approach facilitates further studies on the molecular mechanism of lateral membrane organization and the functional impact of the palmitoylation of MPP1, which could also be carried out for other palmitoylated proteins.
Red Blood Cell Proteasome in Beta-Thalassemia Trait: Topology of Activity and Networking in Blood Bank Conditions
Authors: Anastasiadi Alkmini T. , Tzounakas Vassilis L. , Arvaniti Vasiliki-Zoi , Dzieciatkowska Monika , Stamoulis Konstantinos , Lekka Marilena E. , Papassideri Issidora S. , D’Alessandro Angelo , Kriebardis Anastasios G. , Antonelou Marianna H.
Published: September 2021

Proteasomes are multi-catalytic complexes with important roles in protein control. Their activity in stored red blood cells (RBCs) is affected by both storage time and the donor’s characteristics. However, apart from their abundancy in the membrane proteome, not much is known about their topology, activity, and networking during the storage of RBCs from beta-thalassemia trait donors (βThal+). For this purpose, RBC units from fourteen βThal+ donors were fractionated and studied for proteasome activity distribution and interactome through fluorometric and correlation analyses against units of sex- and aged-matched controls. In all the samples examined, we observed a time-dependent translocation and/or activation of the proteasome in the membrane and a tight connection of activity with the oxidative burden of cells. Proteasomes were more active in the βThal+ membranes and supernatants, while the early storage networking of 20S core particles and activities showed a higher degree of connectivity with chaperones, calpains, and peroxiredoxins, which were nonetheless present in all interactomes. Moreover, the βThal+ interactomes were specially enriched in kinases, metabolic enzymes, and proteins differentially expressed in βThal+ membrane, including arginase-1, piezo-1, and phospholipid scramblase. Overall, it seems that βThal+ erythrocytes maintain a considerable “proteo-vigilance” during storage, which is closely connected to their distinct antioxidant dynamics and membrane protein profile.
Self-Induced Internal Corrosion Stress Transgranular Cracking in Gradient-Structural Ploycrystalline Materials at High Temperature
Authors: Lei Xianjun , Wang Xiaopeng , Kong Fantao , Zhou Haitao , Chen Yuyong
Published: September 2021

Self-induced internal corrosion stress transgranular cracking is investigated theoretically and experimentally linking grain boundary wetting (GBW) and grain boundary diffusion (GBD) to improve the ability to reveal the micro mechanism of crack in compositional gradient-structural intermetallic materials. Theoretical analysis shows that the grain boundary wetting and diffusion induce the diffusion-coupled dynamic internal stresses, and their interaction leads to crack nucleation. The experimental results show a stress concentration zone have been established at the grain boundary interface where the cracks preferentially nucleate and then extend through the inside of the grain to both sides, forming a typical transgranular fracture.
Novel Confinement Possibility for Laser Shock: Use of Flexible Polymer Confinement at 1064 nm Wavelength
Authors: Le Bras Corentin , Rondepierre Alexandre , Ayad Mohammad , Rouchausse Yann , Gervais Matthieu , Valadon Stéphane , Berthe Laurent
Published: September 2021

Through the years, laser shock peening became a treatment of choice in the aerospace industry to prolong the life of certain critical pieces. Water flow is commonly used as a confinement to improve the process capability but some applications cannot allow for water presence in the area of interest. In a previous article, an alternative to the water confinement was presented, a flexible polymer confinement was used and demonstrated the production of pressures equivalent to the water configuration treatment. However, laser parameters have been restricted to a wavelength in the visible range at 532 nm. In this paper, the study is extended to 1064 nm which is commonly used in LSP applications and with two different pulse durations. A 1064 nm near infra-red laser is used to do pressure characterization of shots with polymer confinement through Velocity Interferometer System for Any Reflector (VISAR) measurements coupled with Finite Element Modelling on Abaqus software. The results show that the pressures produced by the confinement is slightly lower with the 1064 nm wavelength, similar to what is observed with the classic water confined regime when switching from 532 nm to a near infra-red wavelength. Nevertheless, the high level of pressure produced by laser shock under the polymer confinement configuration allows for the treatment of common types of metal alloys used in the aerospace industry. Although the use of such a confinement has yet to be applicable to peening setups, it has already uses in some single shot configurations such as LasAT where it allows the avoidance of the water flow optimization.
Hierarchical Morphology and Formation Mechanism of Collision Surface of Al/Steel Dissimilar Lap Joints via Electromagnetic Pulse Welding
Authors: Wang Puquan , Chen Daolun , Yan Yunqi , She Xinwei , Feng Bo , Ran Yang , Peng He , Li Dongyang , Jiang Xianquan
Published: September 2021

The aim of this study was to characterize detailed microstructural changes and bonding characteristics and identify the formation mechanism of collision surface of Al6061–Q355 steel dissimilar welded joints via electromagnetic pulse welding (EMPW). The collision surface was observed to consist of five zones from the center to the outside. The central non-weld zone exhibited a concave and convex morphology. The welding-affected zone mainly included melting features and porous structures, representing a porous joining. The secondary weld zone presented an obvious mechanical joining characterized by shear plateaus with stripes. The primary weld zone characterized by dimples with cavity features suggested the formation of diffusion or metallurgical bonding. The impact-affected zone denoted an invalid interfacial bonding due to discontinuous spot impact. During EMPW, the impact energy and pressure affected the changes of normal velocity and tangential velocity, and in turn, influenced the interfacial deformation behavior and bonding characteristics, including the formation of micropores which continued to grow into homogeneous or uneven porous structures via cavitation, surface tension, and depressurization, along with the effect of trapped air.
Sustainable Steel Industry: Energy and Resource Efficiency, Low-Emissions and Carbon-Lean Production
Authors: Colla Valentina , Branca Teresa Annunziata
Published: September 2021

The three pillars of sustainability represented by the environment, economy and society in the steel manufacturing industry are directly connected to the efficient and effective management of resources, such as energy, raw materials, by-products and water [...]
Role of Heat Treatment on Atomic Order and Ordering Domains in Ni45Co5Mn36.6In13.4 Ribbons
Authors: Feng Yan , Wan Xueman , Bian Xiaohai , Ai Yanling , Wang Haibo
Published: September 2021

The effects of cooling rate and annealed temperature on the state of atomic order and microstructure of L21 domains of Ni45Co5Mn36.6In13.4 ribbons are investigated comprehensively. The state of atomic order is quantitatively studied by in situ X-ray diffraction (XRD), and the microstructure of ordered domains is revealed by transmission electron microscopy (TEM). As-spun ribbons show B2 structure of low atomic order, exhibiting the dispersive L21 domains’ morphology. By applying heat treatment around the order–disorder transition temperature followed by furnace cooling or quenching into water, respectively, we found the strong dependence of ordered domains on cooling rates. Furnace cooling samples show L21 domains with small sized antiphase boundary, revealing a high degree of atomic order, while quenching hinders the formation of ordered domains. Annealing above the order–disorder transition temperature followed by quenching preserves the disordered atomic state with the mixture of L21 structure in B2 matrix.
Minimizing the Negative Effects of Coolant Channels on the Torsional and Torsional-Axial Stiffness of Drills
Authors: Parsian Amir , Eynian Mahdi , Magnevall Martin , Beno Tomas
Published: September 2021

Coolant channels allow internal coolant delivery to the cutting region and significantly improve drilling, but these channels also reduce the torsional and torsional-axial stiffness of the drills. Such a reduction in stiffness can degrade the quality of the drilled holes. The evacuation of cutting chips and the delivery of the cutting fluid put strict geometrical restrictions on the cross-section design of the drill. This necessitates careful selection and optimization of features such as the geometry of the coolant channels. This paper presents a new method that uses Prandtl’s stress function to predict the torsional and torsional-axial stiffness values. Using this method drills with one central channel are compared to those with two eccentric coolant channels, which shows that with the same cross-section area, the reduction of axial and torsional-axial stiffness is notably smaller for the design with two eccentric channels compared to a single central channel. The stress function method is further used to select the appropriate location of the eccentric coolant channels to minimize the loss of torsional and torsional-axial stiffness. These results are verified by comparison to the results of three-dimensional finite element analyses.
Thermoelectric Power in Ce Systems with Unstable Valence
Authors: Toliński Tomasz
Published: September 2021

In this paper, we report on a few exemplary tests of the applicability of analysis based on the interconfiguration fluctuation model (ICF) for a description of the temperature dependence of the thermoelectric power, S(T). The examples include a series of alloys: CeNi2(Si1−yGey)2, Ce(Ni1−xCux)2Si2, and the fluctuating valence (FV) compound CeNi4Ga. The two series develop from CeNi2Si2 being the FV system, where the f states occupation increases progressively with the Ge or Cu substitution. We find here that the ICF model parameters are of similar magnitude both for the analysis of the temperature dependence of the magnetic susceptibility and thermoelectric power. The ICF-type model appears to be a powerful tool for the analysis of S(T) dependences in Ce-based FV compounds and alloys.
Excellent Wear Resistance of a High-Speed Train Brake Disc Steel with High Hardening Ratcheting Strain Zone
Authors: Yang Lei , Zhou Tingwei , Xu Zhenlin , He Yizhu , Hu Xuewen , Zhao Hai
Published: September 2021

Wear resistance of brake discs has a significant effect on the safety of high-speed trains. In this work, the rolling–sliding wear resistance of a low-carbon martensitic brake disc steel was investigated. The microstructure evolution and mechanical properties from the worn surface to the matrix were analyzed to promote parameters for the application of this steel. The results indicated that a ratcheting strain zone was formed at the surface of the brake disc steel under asymmetric cycling load and presented the morphology of the plastic flow line. An equation between the shear strain and the depth from the surface was established, which reflected the gradient distribution of the shear strain. The martensite lath refined into the nano/sub-micron grain and strip on the topmost surface. The micron scratch test results exhibited that the hardening rate and fracture toughness of the ratcheting strain zone varied continually along with depth, and the highest hardening rate occurred on the worn surface due to the increase of dislocation density and grain refinement. Additionally, the brake disc steel obtained better wear resistance than that of other wear-resistant materials used for railways due to steel having the highest hardening rate in the ratcheting strain zone.
Prediction of Cracking Susceptibility of Commercial Aluminum Alloys during Solidification
Authors: Zhang Fan , Liang Songmao , Zhang Chuan , Chen Shuanglin , Lv Duchao , Cao Weisheng , Kou Sindo
Published: September 2021

Cracking during solidification is a complex phenomenon which has been investigated from various angles for decades using both experimental and theoretical methods. In this paper, cracking susceptibility was investigated by a simulation method for three series of aluminum alloys: AA2xxx, AA6xxx, and AA7xxx alloys. The simulation tool was developed using the CALPHAD method and is readily applicable to multicomponent alloy systems. For each series of alloys, cracking susceptible index values were calculated for more than 1000 alloy compositions by high-throughput calculation. Cracking susceptible maps were then constructed for these three series of aluminum alloys using the simulated results. The effects of major and minor alloying elements were clearly demonstrated by these index maps. The cooling rate effect was also studied, and it was concluded that back diffusion in the solid can significantly improve the cracking susceptibility.