bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuregulin 4 Downregulation Induces Insulin Resistance in 3T3-L1 Adipocytes through Inflammation and Autophagic Degradation of GLUT4 Vesicles
Authors: Díaz-Sáez Francisco , Blanco-Sinfreu Carla , Archilla-Ortega Adrià , Sebastian David , Romero Montserrat , Hernández-Alvarez Maria Isabel , Mora Sílvia , Testar Xavier , Ricart Wifredo , Fernández-Real José Manuel , Moreno-Navarrete José María , Aragonés Julián , Camps Marta , Zorzano Antonio , Gumà Anna
Published: November 2021

The adipokine Neuregulin 4 (Nrg4) protects against obesity-induced insulin resistance. Here, we analyze how the downregulation of Nrg4 influences insulin action and the underlying mechanisms in adipocytes. Validated shRNA lentiviral vectors were used to generate scramble (Scr) and Nrg4 knockdown (KD) 3T3-L1 adipocytes. Adipogenesis was unaffected in Nrg4 KD adipocytes, but there was a complete impairment of the insulin-induced 2-deoxyglucose uptake, which was likely the result of reduced insulin receptor and Glut4 protein. Downregulation of Nrg4 enhanced the expression of proinflammatory cytokines. Anti-inflammatory agents recovered the insulin receptor, but not Glut4, content. Proteins enriched in Glut4 storage vesicles such as the insulin-responsive aminopeptidase (IRAP) and Syntaxin-6 as well as TBC1D4, a protein involved in the intracellular retention of Glut4 vesicles, also decreased by Nrg4 KD. Insulin failed to reduce autophagy in Nrg4 KD adipocytes, observed by a minor effect on mTOR phosphorylation, at the time that proteins involved in autophagy such as LC3-II, Rab11, and Clathrin were markedly upregulated. The lysosomal activity inhibitor bafilomycin A1 restored Glut4, IRAP, Syntaxin-6, and TBC1D4 content to those found in control adipocytes. Our study reveals that Nrg4 preserves the insulin responsiveness by preventing inflammation and, in turn, benefits the insulin regulation of autophagy.
Effects of Anesthetic Technique on the Occurrence of Acute Kidney Injury after Spine Surgery: A Retrospective Cohort Study
Authors: Han Jiwon , Oh Ah-Young , Koo Chang-Hoon , Bae Yu Kyung , Jeon Yong-Tae
Published: November 2021

The effects of anesthetics on acute kidney injury (AKI) after spine surgery have not been evaluated fully. This study compared propofol-based total intravenous anesthesia (TIVA) and volatile anesthetics in the development of AKI after spine surgery. This retrospective study reviewed patients who underwent spine surgery between 2015 and 2019. A logistic regression analysis was performed to identify risk factors for AKI. Additionally, after propensity score matching, the incidence of AKI was compared between TIVA and volatile groups. Of the 4473 patients, 709 were excluded and 3764 were included in the logistic regression. After propensity score matching, 766 patients from each group were compared, and we found that the incidence of AKI was significantly lower in the TIVA group (1% vs. 4.2%, p < 0.001). In the multivariate logistic regression analysis, the risk factors for postoperative AKI were male sex (OR 1.85, 95% CI 1.18–3.06), hypertension (OR 2.48, 95% CI 1.56–3.94), anemia (OR 2.66, 95% CI 1.76–4.04), and volatile anesthetics (OR 4.69, 95% CI 2.24–9.84). Compared with volatile anesthetics, TIVA is associated with a reduced risk of AKI for patients who have undergone spine surgery.
Optimizing Land Use and Land Cover Allocation for Flood Mitigation Using Land Use Change and Hydrological Models with Goal Programming, Chaiyaphum, Thailand
Authors: Phinyoyang Athiwat , Ongsomwang Suwit
Published: November 2021

Floods represent one of the most severe natural disasters threatening the development of human society worldwide, including in Thailand. In recent decades, Chaiyaphum province has experienced a problem with flooding almost every year. In particular, the flood in 2010 caused property damage of 495 million Baht, more than 322,000 persons were affected, and approximately 1046.4 km2 of productive agricultural area was affected. Therefore, this study examined how to optimize land use and land cover allocation for flood mitigation using land use change and hydrological models with optimization methods. This research aimed to allocate land use and land cover (LULC) to minimize the surface for flood mitigation in Mueang Chaiyaphum district, Chaiyaphum province, Thailand. The research methodology consisted of six stages: data collection and preparation, LULC classification, LULC prediction, surface runoff estimation, the optimization of LULC allocation for flood mitigation and mapping, and economic and ecosystem service value evaluation and change. According to the results of the optimization and mapping of suitable LULC allocation to minimize surface runoff for flood mitigation in dry, normal, and wet years using goal programming and the CLUE-S model, the suitable LULC allocation for flood mitigation in 2049 under a normal year could provide the highest future economic value and gain. In the meantime, the suitable LULC allocation for flood mitigation in 2049 under a drought year could provide the highest ecosystem service value and gain. Nevertheless, considering future economic and ecosystem service values and changes with surface runoff reduction, the most suitable LULC allocation for flood mitigation is a normal year. Consequently, it can be concluded that the derived results of this study can be used as primary information for flood mitigation project implementation. Additionally, the presented conceptual framework and research workflows can be used as a guideline for government agencies to examine other flood-prone areas for flood mitigation in Thailand.
Growth and Optical Properties of the Whole System of Li(Mn1-x,Nix)PO4 (0 ≤ x ≤ 0.5) Single Crystals
Authors: Xu Benyan , Li Zhenyou , Wang Kunpeng , Zhang Jianxiu , Liang Lanju , Li Longfei , Ren Yanbiao , Liu Yong , Liu Meng , Xue Dongfeng
Published: November 2021

A series of single crystals of Li(Mn1-x,Nix)PO4 (x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08, 0.10, 0.15, 0.20, and 0.50) have been grown to large sizes up to 5 mm in diameter and 120 mm in length using the floating zone method for the first time. The comprehensive characterizations of the as-grown crystals were performed before further physical property measurements. The composition of the grown crystals was determined by energy-dispersive X-ray spectroscopy. The crystal structures were characterized by the X-ray powder diffraction method with a GSAS fitting for structural refinement, which reveals a high phase purity of the as-obtained crystals. The polarized microscopic images and Laue patterns prove the excellent quality of the single crystals. Oriented cuboids with sizes of 2.7 × 3.8 × 2.1 mm3 along the a, b, and c crystalline directions were cut and polished for further anisotropic magnetic and transparent measurements. We also first proposed a new potential application in the non-linear optical (NLO) and laser generation application for LiMPO4 (M = transition metal) materials. The optical and laser properties, such as the absorption spectra and the second harmonic generation (SHG), have been investigated and have furthermore confirmed the good quality of the as-grown single crystals.
Extremely Fast and Cheap Densification of Cu2S by Induction Melting Method
Authors: Nieroda Paweł , Ziewiec Krzysztof , Leszczyński Juliusz , Rutkowski Paweł , Koleżyński Andrzej
Published: November 2021

The aim of this work was to obtain dense Cu2S superionic thermoelectric materials, homogeneous in terms of phase and chemical composition, using a very fast and cheap induction-melting technique. The chemical composition was investigated via scanning electron microscopy (SEM) combined with an energy-dispersive spectroscopy (EDS) method, and the phase composition was established by X-ray diffraction (XRD). The thermoelectric figure of merit ZT was determined on the basis of thermoelectric transport properties, i.e., Seebeck coefficient, electrical and thermal conductivity in the temperature range of 300–923 K. The obtained values of the ZT parameter are comparable with those obtained using the induction hot pressing (IHP) technique and about 30–45% higher in the temperature range of 773–923 K in comparison with Cu2S samples densified with the spark plasma sintering (SPS) technique.
Thermal-Fluid–Solid Coupling—Parametrical Numerical Analysis of Hot Turbine Nozzle Guide Vane
Authors: Froissart Marcin , Ochrymiuk Tomasz
Published: November 2021

The cooling technology of hot turbine components has been a subject of continuous improvement for decades. In high-pressure turbine blades, the regions most affected by the excessive corrosion are the leading and trailing edges. In addition, high Kt regions at the hot gas path are exposed to cracking due to the low and high cycle fatigue failure modes. Especially in the case of a nozzle guide vane, the ability to predict thermally driven loads is crucial to assess its life and robustness. The difficulties in measuring thermal properties in hot conditions considerably limit the number of experimental results available in the literature. One of the most popular test cases is a NASA C3X vane, but coolant temperature is not explicitly revealed in the test report. As a result of that, numerous scientific works validated against that vane are potentially inconsistent. To address that ambiguity, the presented work was performed on a fully structural and a very fine mesh assuming room inlet temperature on every cooling channel. Special attention was paid to the options of the k−ω SST (shear-stress transport) viscosity model, such as Viscous heating (VH), Curvature correction (CC), Production Kato-Launder (KT), and Production limiter (PL). The strongest impact was from the Viscous heating, as it increases local vane temperature by as much as 40 deg. The significance of turbulent Prandtl number impact was also investigated. The default option used in the commercial CFD code is set to 0.85. Presented study modifies that value using equations proposed by Wassel/Catton and Kays/Crawford. Additionally, the comparison between four, two, and one-equation viscosity models was performed.
Effect of Temperature on the Tribological Properties of Selected Thermoplastic Materials Cooperating with Aluminium Alloy
Authors: Ptak Anita , Taciak Paula , Wieleba Wojciech
Published: November 2021

This article concerns the tribological properties of three selected polymer materials: polyamide PA6, polyethylene PE-HD and polyetheretherketone composite PEEK/BG during sliding against aluminium alloy EN AW-2017A in the presence of hydraulic oil HLP 68. The tests were carried out under contact pressure p of 3.5–11 MPa at ambient temperature T ranging from −20 °C to +20 °C. The dependence of kinetic friction coefficient μk on the two parameters was determined through tribological tests carried out using a pin-on-disc tribometer. A five-level central composite rotatable design (CCRD) was adopted for the experiment. All the test results were statistically analysed. The microhardness of the surface of the polymeric material was measured before and after the friction process. The surface was also examined under SEM. Temperature and contact pressure have been found to have a significant effect on the tribological properties of the tested sliding pairs. Relative to the applied friction conditions, the surfaces after friction showed rather heavy signs of wear.
Tribological Behavior and Microstructural Analysis of Atmospheric Plasma Spray Deposited Thin Coatings on Cardan Cross Spindles
Authors: Munteanu Corneliu , Paleu Viorel , Istrate Bogdan , Dascălu Anişoara , Cîrlan Paleu Cornelia , Bhaumik Shubrajit , Ancaş Ana Diana
Published: November 2021

Cardan joints are used in transmissions between misaligned shafts, as in all-wheel-drive (AWD) cars and railway applications. Their functioning is accompanied by heavy cyclical loads, with the cardan cross spindles subjected to intensive abrasive wear and pitting. In this paper, a solution to the mentioned issue is proposed, thin anti-wear coatings of Metco 32 and Metco 72 metallic powders deposited by atmospheric plasma spray (APS) on cylindrical samples cut from spindles of two cardan crosses made of 40Cr10 and RUL2 steel. The morphological analysis of the coated surfaces was realized by scanning electron microscopy (SEM), and the elemental composition of the tested samples was elaborated by energy-dispersive X-ray spectroscopy (EDS). To investigate the wear resistance of the coated samples in dry and grease-lubricated conditions, tests at constant load and constant speed were carried out using an AMSLER tribometer. The results of greased tests proved that the expulsion of the lubricant from the tribological contact occurred no matter the combination of coated or uncoated samples. During grease-lubricated tests of ten minutes, the least coefficient of friction was measured for uncoated specimens with better surface finishing; but in dry friction tests, the lowest values of the mean friction coefficients were obtained for the Metco 72 coatings. The porous coatings may act as lubricant reservoirs in long-lasting tests, providing a solution to the expulsion phenomenon of the lubricant to the boundary outside the area of the larger-diameter roller.
Calderón Operator on Local Morrey Spaces with Variable Exponents
Authors: Ho Kwok-Pun
Published: November 2021

In this paper, we establish the boundedness of the Calderón operator on local Morrey spaces with variable exponents. We obtain our result by extending the extrapolation theory of Rubio de Francia to the local Morrey spaces with variable exponents. The exponent functions of the local Morrey spaces with the exponent functions are only required to satisfy the log-Hölder continuity assumption at the origin and infinity only. As special cases of the main result, we have Hardy’s inequalities, the Hilbert inequalities and the boundedness of the Riemann–Liouville and Weyl averaging operators on local Morrey spaces with variable exponents.
Inverse Spectral Problems for Arbitrary-Order Differential Operators with Distribution Coefficients
Authors: Bondarenko Natalia P.
Published: November 2021

In this paper, we propose an approach to inverse spectral problems for the n-th order (n≥2) ordinary differential operators with distribution coefficients. The inverse problems which consist in the reconstruction of the differential expression coefficients by the Weyl matrix and by several spectra are studied. We prove the uniqueness of solution for these inverse problems, by developing the method of spectral mappings. The results of this paper generalize the previously known results for the second-order differential operators with singular potentials and for the higher-order differential operators with regular coefficients. In the future, the approach of this paper can be used for constructive solution and for investigation of solvability of the considered inverse problems.
On the Use of Gradient Boosting Methods to Improve the Estimation with Data Obtained with Self-Selection Procedures
Authors: Castro-Martín Luis , Rueda María del Mar , Ferri-García Ramón , Hernando-Tamayo César
Published: November 2021

In the last years, web surveys have established themselves as one of the main methods in empirical research. However, the effect of coverage and selection bias in such surveys has undercut their utility for statistical inference in finite populations. To compensate for these biases, researchers have employed a variety of statistical techniques to adjust nonprobability samples so that they more closely match the population. In this study, we test the potential of the XGBoost algorithm in the most important methods for estimation that integrate data from a probability survey and a nonprobability survey. At the same time, a comparison is made of the effectiveness of these methods for the elimination of biases. The results show that the four proposed estimators based on gradient boosting frameworks can improve survey representativity with respect to other classic prediction methods. The proposed methodology is also used to analyze a real nonprobability survey sample on the social effects of COVID-19.
Contact-Complex Riemannian Submersions
Authors: Bejan Cornelia-Livia , Meriç Şemsi Eken , Kılıç Erol
Published: November 2021

A submersion from an almost contact Riemannian manifold to an almost Hermitian manifold, acting on the horizontal distribution by preserving both the metric and the structure, is, roughly speaking a contact-complex Riemannian submersion. This paper deals mainly with a contact-complex Riemannian submersion from an η-Ricci soliton; it studies when the base manifold is Einstein on one side and when the fibres are η-Einstein submanifolds on the other side. Some results concerning the potential are also obtained here.
Contrast-Independent, Partially-Explicit Time Discretizations for Nonlinear Multiscale Problems
Authors: Chung Eric T. , Efendiev Yalchin , Leung Wing Tat , Li Wenyuan
Published: November 2021

This work continues a line of work on developing partially explicit methods for multiscale problems. In our previous works, we considered linear multiscale problems where the spatial heterogeneities are at the subgrid level and are not resolved. In these works, we have introduced contrast-independent, partially explicit time discretizations for linear equations. The contrast-independent, partially explicit time discretization divides the spatial space into two components: contrast dependent (fast) and contrast independent (slow) spaces defined via multiscale space decomposition. Following this decomposition, temporal splitting was proposed, which treats fast components implicitly and slow components explicitly. The space decomposition and temporal splitting are chosen such that they guarantees stability, and we formulated a condition for the time stepping. This condition was formulated as a condition on slow spaces. In this paper, we extend this approach to nonlinear problems. We propose a splitting approach and derive a condition that guarantees stability. This condition requires some type of contrast-independent spaces for slow components of the solution. We present numerical results and show that the proposed methods provide results similar to implicit methods with a time step that is independent of the contrast.
A New Goodness of Fit Test for Multivariate Normality and Comparative Simulation Study
Authors: Arnastauskaitė Jurgita , Ruzgas Tomas , Bražėnas Mindaugas
Published: November 2021

The testing of multivariate normality remains a significant scientific problem. Although it is being extensively researched, it is still unclear how to choose the best test based on the sample size, variance, covariance matrix and others. In order to contribute to this field, a new goodness of fit test for multivariate normality is introduced. This test is based on the mean absolute deviation of the empirical distribution density from the theoretical distribution density. A new test was compared with the most popular tests in terms of empirical power. The power of the tests was estimated for the selected alternative distributions and examined by the Monte Carlo modeling method for the chosen sample sizes and dimensions. Based on the modeling results, it can be concluded that a new test is one of the most powerful tests for checking multivariate normality, especially for smaller samples. In addition, the assumption of normality of two real data sets was checked.
One-Machine Scheduling with Time-Dependent Capacity via Efficient Memetic Algorithms
Authors: Mencía Raúl , Mencía Carlos
Published: November 2021

This paper addresses the problem of scheduling a set of jobs on a machine with time-varying capacity, with the goal of minimizing the total tardiness objective function. This problem arose in the context scheduling the charging times of a fleet of electric vehicles and it is NP-hard. Recent work proposed an efficient memetic algorithm for solving the problem, combining a genetic algorithm and a local search method. The local search procedure is based on swapping consecutive jobs on a C-path, defined as a sequence of consecutive jobs in a schedule. Building on it, this paper develops new memetic algorithms that stem from new local search procedures also proposed in this paper. The local search methods integrate several mechanisms to make them more effective, including a new condition for swapping pairs of jobs, a hill climbing approach, a procedure that operates on several C-paths and a method that interchanges jobs between different C-paths. As a result, the new local search methods enable the memetic algorithms to reach higher-quality solutions. Experimental results show significant improvements over existing approaches.
Multi-Drone 3D Building Reconstruction Method
Authors: Filatov Anton , Zaslavskiy Mark , Krinkin Kirill
Published: November 2021

In the recent decade, the rapid development of drone technologies has made many spatial problems easier to solve, including the problem of 3D reconstruction of large objects. A review of existing solutions has shown that most of the works lack the autonomy of drones because of nonscalable mapping techniques. This paper presents a method for centralized multi-drone 3D reconstruction, which allows performing a data capturing process autonomously and requires drones equipped only with an RGB camera. The essence of the method is a multiagent approach—the control center performs the workload distribution evenly and independently for all drones, allowing simultaneous flights without a high risk of collision. The center continuously receives RGB data from drones and performs each drone localization (using visual odometry estimations) and rough online mapping of the environment (using image descriptors for estimating the distance to the building). The method relies on a set of several user-defined parameters, which allows the tuning of the method for different task-specific requirements such as the number of drones, 3D model detalization, data capturing time, and energy consumption. By numerical experiments, it is shown that method parameters can be estimated by performing a set of computations requiring characteristics of drones and the building that are simple to obtain. Method performance was evaluated by an experiment with virtual building and emulated drone sensors. Experimental evaluation showed that the precision of the chosen algorithms for online localization and mapping is enough to perform simultaneous flights and the amount of captured RGB data is enough for further reconstruction.
A New Attractive Method in Solving Families of Fractional Differential Equations by a New Transform
Authors: Qazza Ahmad , Burqan Aliaa , Saadeh Rania
Published: November 2021

In this paper, we use the ARA transform to solve families of fractional differential equations. New formulas about the ARA transform are presented and implemented in solving some applications. New results related to the ARA integral transform of the Riemann-Liouville fractional integral and the Caputo fractional derivative are obtained and the last one is implemented to create series solutions for the target equations. The procedure proposed in this article is mainly based on some theorems of particular solutions and the expansion coefficients of binomial series. In order to achieve the accuracy and simplicity of the new method, some numerical examples are considered and solved. We obtain the solutions of some families of fractional differential equations in a series form and we show how these solutions lead to some important results that include generalizations of some classical methods.
On a Parallelised Diffusion Induced Stochastic Algorithm with Pure Random Search Steps for Global Optimisation
Authors: Esquível Manuel L. , Krasii Nadezhda P. , Mota Pedro P. , Machado Nélio
Published: November 2021

We propose a stochastic algorithm for global optimisation of a regular function, possibly unbounded, defined on a bounded set with regular boundary; a function that attains its extremum in the boundary of its domain of definition. The algorithm is determined by a diffusion process that is associated with the function by means of a strictly elliptic operator that ensures an adequate maximum principle. In order to preclude the algorithm to be trapped in a local extremum, we add a pure random search step to the algorithm. We show that an adequate procedure of parallelisation of the algorithm can increase the rate of convergence, thus superseding the main drawback of the addition of the pure random search step.
Rock Segmentation in the Navigation Vision of the Planetary Rovers
Authors: Kuang Boyu , Wisniewski Mariusz , Rana Zeeshan A. , Zhao Yifan
Published: November 2021

Visual navigation is an essential part of planetary rover autonomy. Rock segmentation emerged as an important interdisciplinary topic among image processing, robotics, and mathematical modeling. Rock segmentation is a challenging topic for rover autonomy because of the high computational consumption, real-time requirement, and annotation difficulty. This research proposes a rock segmentation framework and a rock segmentation network (NI-U-Net++) to aid with the visual navigation of rovers. The framework consists of two stages: the pre-training process and the transfer-training process. The pre-training process applies the synthetic algorithm to generate the synthetic images; then, it uses the generated images to pre-train NI-U-Net++. The synthetic algorithm increases the size of the image dataset and provides pixel-level masks—both of which are challenges with machine learning tasks. The pre-training process accomplishes the state-of-the-art compared with the related studies, which achieved an accuracy, intersection over union (IoU), Dice score, and root mean squared error (RMSE) of 99.41%, 0.8991, 0.9459, and 0.0775, respectively. The transfer-training process fine-tunes the pre-trained NI-U-Net++ using the real-life images, which achieved an accuracy, IoU, Dice score, and RMSE of 99.58%, 0.7476, 0.8556, and 0.0557, respectively. Finally, the transfer-trained NI-U-Net++ is integrated into a planetary rover navigation vision and achieves a real-time performance of 32.57 frames per second (or the inference time is 0.0307 s per frame). The framework only manually annotates about 8% (183 images) of the 2250 images in the navigation vision, which is a labor-saving solution for rock segmentation tasks. The proposed rock segmentation framework and NI-U-Net++ improve the performance of the state-of-the-art models. The synthetic algorithm improves the process of creating valid data for the challenge of rock segmentation. All source codes, datasets, and trained models of this research are openly available in Cranfield Online Research Data (CORD).
Methodology for Constructing and Using a Mathematical Model for Assessing Labor Costs for the Development of Distance Learning Courses
Authors: Misnevs Boriss , Puptsau Aliaksandr , Jusas Vacius
Published: November 2021

Distance learning plays a significant role in solving the problem of the sustainable development of society. Unfortunately, the development and implementation of distance courses are still carried out intuitively, which does not allow practical implementation of effective mathematics methods and slows down the introduction of breakthrough technologies. The aim of the research was to develop a new model and a methodology for assessing the labor costs of designing distance learning courses by university teachers based on a comprehensive assessment of the courses’ quality. The suggested model originally extends the constructive cost evaluation model already used in IT industry. The developed criteria make it possible to assess labor costs in relation to the quality of course development. The paper provides and analyzes such calculations on the example of courses in the theory of algorithms and programming.
Spreading of Infections on Network Models: Percolation Clusters and Random Trees
Authors: Roman Hector Eduardo , Croccolo Fabrizio
Published: November 2021

We discuss network models as a general and suitable framework for describing the spreading of an infectious disease within a population. We discuss two types of finite random structures as building blocks of the network, one based on percolation concepts and the second one on random tree structures. We study, as is done for the SIR model, the time evolution of the number of susceptible (S), infected (I) and recovered (R) individuals, in the presence of a spreading infectious disease, by incorporating a healing mechanism for infecteds. In addition, we discuss in detail the implementation of lockdowns and how to simulate them. For percolation clusters, we present numerical results based on site percolation on a square lattice, while for random trees we derive new analytical results, which are illustrated in detail with a few examples. It is argued that such hierarchical networks can complement the well-known SIR model in most circumstances. We illustrate these ideas by revisiting USA COVID-19 data.
Asymptotic Properties of Solutions to Delay Differential Equations Describing Plankton—Fish Interaction
Authors: Skvortsova Maria A.
Published: November 2021

We consider a system of differential equations with two delays describing plankton–fish interaction. We analyze the case when the equilibrium point of this system corresponding to the presence of only phytoplankton and the absence of zooplankton and fish is asymptotically stable. In this case, the asymptotic behavior of solutions to the system is studied. We establish estimates of solutions characterizing the stabilization rate at infinity to the considered equilibrium point. The results are obtained using Lyapunov–Krasovskii functionals.
Unified Mathematical Formulation of Monogenic Phase Congruency
Authors: Forero Manuel G. , Jacanamejoy Carlos A.
Published: November 2021

Phase congruency is a technique that has been used for edge, corner and symmetry detection. Its implementation through the use of monogenic filters has improved its computational cost. For this purpose, different methods of implementation have been published, but they do not use a common notation, which makes it difficult to understand. Therefore, this paper presents a unified mathematical formulation that allows a general understanding of the Monogenic phase congruency concepts and establishes criteria for its use. A new protocol for parameter tuning is also described, allowing better practical results to be obtained with this technique. Some examples are presented allowing one to observe the changes produced in the parameter tuning, evidencing the validity of the proposed criteria.
The Due Date Assignment Scheduling Problem with Delivery Times and Truncated Sum-of-Processing-Times-Based Learning Effect
Authors: Qian Jin , Zhan Yu
Published: November 2021

This paper considers a single-machine scheduling problem with past-sequence-dependent delivery times and the truncated sum-of-processing-times-based learning effect. The goal is to minimize the total costs that comprise the number of early jobs, the number of tardy jobs and due date. The due date is a decision variable. There will be corresponding penalties for jobs that are not completed on time. Under the common due date, slack due date and different due date, we prove that these problems are polynomial time solvable. Three polynomial time algorithms are proposed to obtain the optimal sequence.
Impact of COVID-19 on the Robustness of the Probability of Default Estimation Model
Authors: Hung Ming-Chin , Ching Yung-Kang , Lin Shih-Kuei
Published: November 2021

Probability of default (PD) estimation is essential to the calculation of expected credit loss under the Basel III framework and the International Financial Reporting Standard 9. Gross domestic product (GDP) growth has been adopted as a key determinant in PD estimation models. However, PD models with a GDP covariate may not perform well under aberrant (i.e., outlier) conditions such as the COVID-19 pandemic. This study explored the robustness of a PD model with a GDP determinant (the test model) in comparison with that of a PD model with a credit default swap index (CDX) determinant (the alternative model). The test model had a significantly greater ratio of increase in Akaike information criterion than the alternative model in comparisons of the fit performance of models including 2020 data with that of models excluding 2020 data (i.e., that do not cover the COVID-19 pandemic). Furthermore, the Cook’s distance of the 2020 data of the test model was significantly greater than that of the alternative model. Therefore, the test model exhibited a serious robustness issue in outlier scenarios, such as the COVID-19 pandemic, whereas the alternative model was more robust. This finding opens the prospect for the CDX to potentially serve as an alternative to GDP in PD estimation models.
AI versus Classic Methods in Modelling Isotopic Separation Processes: Efficiency Comparison
Authors: Mureșan Vlad , Ungureșan Mihaela-Ligia , Abrudean Mihail , Vălean Honoriu , Clitan Iulia , Motorga Roxana , Ceuca Emilian , Fișcă Marius
Published: November 2021

In the paper, the comparison between the efficiency of using artificial intelligence methods and the efficiency of using classical methods in modelling the industrial processes is made, considering as a case study the separation process of the 18O isotope. Firstly, the behavior of the considered isotopic separation process is learned using neural networks. The comparison between the efficiency of these methods is highlighted by the simulations of the process model, using the mentioned modelling techniques. In this context, the final part of the paper presents the proposed model being simulated in different scenarios that can occur in practice, thus resulting in some interesting interpretations and conclusions. The paper proves the feasibility of using artificial intelligence methods for industrial processes modeling; the obtained models being intended for use in designing automatic control systems.
A Collagen Basketweave from the Giant Squid Mantle as a Robust Scaffold for Tissue Engineering
Authors: Frolova Anastasia , Aksenova Nadezhda , Novikov Ivan , Maslakova Aitsana , Gafarova Elvira , Efremov Yuri , Bikmulina Polina , Elagin Vadim , Istranova Elena , Kurkov Alexandr , Shekhter Anatoly , Kotova Svetlana , Zagaynova Elena , Timashev Peter
Published: November 2021

The growing applications of tissue engineering technologies warrant the search and development of biocompatible materials with an appropriate strength and elastic moduli. Here, we have extensively studied a collagenous membrane (GSCM) separated from the mantle of the Giant squid Dosidicus Gigas in order to test its potential applicability in regenerative medicine. To establish the composition and structure of the studied material, we analyzed the GSCM by a variety of techniques, including amino acid analysis, SDS-PAGE, and FTIR. It has been shown that collagen is a main component of the GSCM. The morphology study by different microscopic techniques from nano- to microscale revealed a peculiar packing of collagen fibers forming laminae oriented at 60–90 degrees in respect to each other, which, in turn, formed layers with the thickness of several microns (a basketweave motif). The macro- and micromechanical studies showed high values of the Young’s modulus and tensile strength. No significant cytotoxicity of the studied material was found by the cytotoxicity assay. Thus, the GSCM consists of a reinforced collagen network, has high mechanical characteristics, and is non-toxic, which makes it a good candidate for the creation of a scaffold material for tissue engineering.
Polypharmacy in the Management of Arterial Hypertension—Friend or Foe?
Authors: Diaconu Camelia Cristina , Cozma Matei-Alexandru , Dobrică Elena-Codruța , Gheorghe Gina , Jichitu Alexandra , Ionescu Vlad Alexandru , Nicolae Alina Crenguța , Drăgoi Cristina Manuela , Găman Mihnea-Alexandru
Published: November 2021

Background and Objectives: Polypharmacy is associated with drug–drug or food–drug interactions that may pose treatment difficulties. The objective of the study was to investigate the use of polypharmacy in hypertensive patients hospitalized in the Internal Medicine Clinic of a European referral hospital. Materials and Methods: We conducted a retrospective chart review study on patients identified by a database search of discharge diagnoses to assess the use of polypharmacy and identify potential drug-drug and food-drug interactions. Results: In total, 166 hypertensive patients (68.46 ± 12.70 years, range 42–94 years) were compared to 83 normotensive subjects (67.82 ± 14.47 years, range 22–94 years) who were hospitalized in the clinic during the same period. Polypharmacy was more common in hypertensive versus normotensive subjects (p = 0.007). There were no differences in terms of age, as well as major (0.44 ± 0.77 versus 0.37 ± 0.73 interactions/patient, p = 0.52) and minor (1.25 ± 1.50 versus 1.08 ± 1.84 interactions/patient, p = 0.46) drug–drug interactions between patients with and without hypertension. The mean number of drug–drug interactions (6.55 ± 5.82 versus 4.93 ± 5.59 interactions/patient, p = 0.03), moderate drug–drug interactions (4.94 ± 4.75 versus 3.54 ± 4.17, p = 0.02) and food–drug interactions (2.64 ± 1.29 versus 2.02 ± 1.73, p = 0.00) was higher in patients with hypertension versus their counterparts. Conclusions: The present study reinforces that polypharmacy is a serious concern in hypertensive patients, as reflected by the high number of potentially harmful drug–drug or food–drug interactions. We recorded higher numbers of comorbidities, prescribed drugs, and moderate drug–drug/food–drug interactions in hypertensive versus normotensive patients. A strategy to evaluate the number of discharge medications and reduce drug–drug interactions is essential for the safety of hypertensive patients.
Virtual Navigator Real-Time Ultrasound Fusion Imaging with Positron Emission Tomography/Computed Tomography for Preoperative Breast Cancer
Authors: Mori Mio , Kubota Kazunori , Fujioka Tomoyuki , Katsuta Leona , Yashima Yuka , Nomura Kyoko , Yamaga Emi , Tsuchiya Junichi , Hosoya Tokuko , Oda Goshi , Nakagawa Tsuyoshi , Onishi Iichiroh , Tateishi Ukihide
Published: November 2021

We used virtual navigator real-time ultrasound (US) fusion imaging with 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to identify a lesion that could not be detected on the US alone in a preoperative breast cancer patient. Of the patient’s two lesions of breast cancer, the calcified lesion could not be identified by US alone. By fusing US with 18F-FDG PET/CT, which had been performed in advance, the location of the lesion could be estimated and marked, which benefited planning an appropriate surgery. The fusion of US and 18F-FDG PET/CT was a simple and noninvasive method for identifying the lesions detected by 18F-FDG PET/CT.
Mitigating Silica Fouling and Improving PPCP Removal by Modified NF90 Using In Situ Radical Graft Polymerization
Authors: Lin Yi-Li , Zheng Nai-Yun , Gan Hao-Yu , Chang An-Xian , Luo Huai-Xuan , Mao Yao-Jie
Published: November 2021

This study in-situ modified a commercial nanofiltration membrane, NF90, through the concentration-polymerization-enhanced radical graft polarization method by applying two agents of 3-sulfopropyl methacrylate potassium salt (SPM) and 2-hydroxyethyl methacrylate (HEMA) with different dosages. Surface characterization revealed that the modified membranes became rougher and more hydrophilic compared with the pristine membrane. The modified membranes exhibited considerably enhanced separation performance with 5.8–19.6% higher NaCl rejection and 17.2–19.9% higher pharmaceuticals and personal care products (PPCPs) rejection than the pristine membrane. When treating the feedwater with high silica concentration, the modified membranes exhibited relatively less flux decline with high percentage of reversible fouling, especially the ones modified using a lower monomer concentration (0.01 M SPM and 0.01 M HEMA). Moreover, membrane modification enhanced the PPCP rejection (1.3–5.4%) after silica fouling by mitigating foulant deposition on the membrane surface. The fouling mechanism was confirmed to be intermediate blocking of membrane pores. Therefore, the in-situ modification technique with a low monomer concentration proved to be effective for mitigating silica fouling and improving PPCP rejection, which can be easily performed and cost-effective in practical application.
Liposome Sterile Filtration Characterization via X-ray Computed Tomography and Confocal Microscopy
Authors: Johnson Thomas F. , Jones Kyle , Iacoviello Francesco , Turner Stephen , Jackson Nigel B. , Zourna Kalliopi , Welsh John H. , Shearing Paul R. , Hoare Mike , Bracewell Daniel G.
Published: November 2021

Two high resolution, 3D imaging techniques were applied to visualize and characterize sterilizing grade dual-layer filtration of liposomes, enabling membrane structure to be related with function and performance. Two polyethersulfone membranes with nominal retention ratings of 650 nm and 200 nm were used to filter liposomes of an average diameter of 143 nm and a polydispersity index of 0.1. Operating conditions including differential pressure were evaluated. X-ray computed tomography at a pixel size of 63 nm was capable of resolving the internal geometry of each membrane. The respective asymmetry and symmetry of the upstream and downstream membranes could be measured, with pore network modeling used to identify pore sizes as a function of distance through the imaged volume. Reconstructed 3D digital datasets were the basis of tortuous flow simulation through each porous structure. Confocal microscopy visualized liposome retention within each membrane using fluorescent dyes, with bacterial challenges also performed. It was found that increasing pressure drop from 0.07 MPa to 0.21 MPa resulted in differing fluorescent retention profiles in the upstream membrane. These results highlighted the capability for complementary imaging approaches to deepen understanding of liposome sterilizing grade filtration.
Modeling and Simulation of Either Co-Current or Countercurrent Operated Reverse-Osmosis-Based Air Water Generator
Authors: Fill Marc , Kleingries Mirko
Published: November 2021

Technologies for obtaining drinkable water are becoming more important as global water consumption steadily increases and climate change progresses. One possibility for obtaining water is the extraction of water vapor from ambient air by means of air water generators (AWG). Previous studies in the field of AWG have mainly dealt with the condensation of humidity on cold surfaces with a cooling system or with absorption and thermal desorption. In this paper, another possibility for AWG is investigated, specifically AWG using absorption and reverse osmosis. For this purpose, models have been set up for an absorber operated in countercurrent and reverse osmosis membrane modules operated in co-current and countercurrent. With these models, simulations with different boundary conditions were then carried out using the programming language Python. The simulations have shown that the reverse osmosis membrane modules operated in countercurrent generally have a lower energy demand and require fewer reverse osmosis stages than those operated in co-current.
Physicochemical Properties of Membrane Adsorber from Palm Empty Fruit Bunch (PEFB) by Acid Activation
Authors: Hidayah Nur , Elma Muthia , Darsono Putri Vidiasari , Syauqiah Isna , Amenia Angelica , Laksana Putra Daniel Guntur , Akbar Heru Renaldi , Huda Nurul , Rahma Aulia
Published: November 2021

A membrane adsorbent was successfully made from palm empty fruit bunches (PEFB), which was pyrolysed as physical activation. The effect of adding the impact of one-step catalyst (hydrochloric acid) and differences in the concentration on the characteristics and structure and deconvolution are investigated in this study. The results of the research have been successfully created and characterised using Fourier-Transform Infrared (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) isotherm, and membrane morphology using SEM test. Membrane performance testing was carried out using a biogas flame test. The adsorber membrane was made by adding NH4Cl as a cationic surfactant, polyvinyl acetate (PVA), and polyethylene glycol (PEG) with a ratio of 1:3. The FTIR test has a functional group: O-H; C-H stretch; C=C-C; Arly O-Strech; C-O. Adsorbent membrane with the addition of 0.5 M HCl catalyst had the highest ratio of O-H/C=C-C relative area of 4.33. The diffractogram shows an amorphous structure with (002) and (100) graph planes. Adsorber membrane with a concentration of 1.5 M HCl has formed amorphous structured fibre. The adsorber membrane with a concentration of 0.5 HCl activator gave a surface area of 0.5345 m2 g−1 and a pore volume of 0.000983 cm3 g−1.
Poly(styrene-co-butadiene)/Maghnia-Organo-Montmorillonite Clay Nanocomposite. Preparation, Properties and Application as Membrane in the Separation of Methanol/Toluene Azeotropic Mixture by Pervaporation
Authors: Allel Amina , Benguergoura Hassiba , Naceur Mohamed Wahib , Ledoux Alain , Saeed Waseem Sharaf , Aouak Taïeb
Published: November 2021

In order to improve the thermal and mechanical properties of poly(styrene-co-butadiene) (SBR) to use it as a pervaporation membrane in the separation of the azeotropic mixture toluene/methanol, poly(styrene-co-butadiene) crosslinked Maghnia-organo-montmonrillonite (CSBR/OMMT), a nanocomposite of different compositions was first prepared by a solvent casting method. SBR was crosslinked in situ in the presence of OMMT nanoparticles by an efficient vulcanization technique using sulfur as a crosslinking agent and zinc diethyldithiocarbamate as a catalyst. The structure and morphology of the hybrid materials obtained were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscope analysis. The thermal properties of these hybrid materials were studied by differential scanning calorimetry and thermogravimetric analysis/thermal differential analysis. The mechanical properties were studied by strength measurements. The results obtained occurred when the OMMT was incorporated in the CSBR matrix; a significant increase in the glass transition temperature of the SBR was observed which passed from −27 °C for virgin SBR to −21.5 °C for that containing 12 wt% of OMMT. The addition of OMMT nanoparticles to CSBR also improved the mechanical properties of this copolymer. When the OMMT content in the CSBR varied from 0 to 15% by weight, the tensile strength, the elongation at the nose and the modulus at 100% elongation increased from 3.45 to 6.25 MPa, from 162, 17 to 347.20% and 1.75 to 3.0 MPa, respectively. The results of pervaporation revealed that when the OMMT content varied between 3% and 12%, a significant increase in the total flux, the separation factor and the separation index by pervaporation increased from 260.67 to g m−2 h−1, 0.31 to 1.43, and 0.47 to 113.81 g m−2 h−1, respectively.
Development of Pure Silica CHA Membranes for CO2 Separation
Authors: Figueiredo Gabriel Gama da Silva , Takayama Daishi , Ishii Katsunori , Nomura Mikihiro , Onoki Takamasa , Okuno Takuya , Tawarayama Hiromasa , Ishikawa Shinji
Published: November 2021

Thin pure-silica chabazite (Si-CHA) membranes have been synthesized by using a secondary growth method on a porous silica substrate. A CO2 permeance of 2.62 × 10−6 mol m−2 s−1 Pa−1 with a CO2/CH4 permeance ratio of 62 was obtained through a Si-CHA membrane crystallized for 8 h using a parent gel of H2O/SiO2 ratio of 4.6. The CO2 permeance through the Si-CHA membrane on a porous silica substrate was twice as high as that through the membrane synthesized on a porous alumina substrate, which displayed a similar zeolite layer thickness.