bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficiency and Competitiveness of the Equatorial Guinean Financial Sector
Authors: Ela-Medja Tito Ondo , Alberca Pilar
Published: January 2023

The private sector, in order to function properly, needs financing from the national financial sector, and so the efficiency and competitiveness of said financial sector arouse the interest of many researchers, who perform analyses in order to provide authorities and decision makers with relevant information for the decision-making process and the design of their financial policies. This study contributes to this line of research, analyzing both technical and economic efficiency (allocative and cost efficiency) in the financial sector, focusing on banks, using a sample of Equatorial Guinean firms during the period of 2013–2019. Furthermore, the competitiveness of the financial sector is also analyzed. Knowing how efficient and competitive the financial sector is could answer many of the questions that arise when regulating the national business sector. To carry out this analysis, parametric approaches such as stochastic frontiers and non-parametric techniques such as data envelopment analysis are used, as well as different competitiveness indicators (Boone, Panzar–Rosse). During the research, it is found that the banking sector, which represents the financial sector of the country, operates with low levels of technical efficiency: the Cobb–Douglas production function and the trans-logarithmic production function showed similar average efficiency results. Regarding competitiveness, the financial sector operates under monopolistic competition. Therefore, much remains to be achieved to improve the efficiency and competitiveness of the financial sector for the development of Equatorial Guinea. It is the responsibility of economic agents to provide a good business climate in the country and guarantee perfect competition in the financial market to promote national development.
CNN-Based Temporal Video Segmentation Using a Nonlinear Hyperbolic PDE-Based Multi-Scale Analysis
Authors: Barbu Tudor
Published: January 2023

An automatic temporal video segmentation framework is introduced in this article. The proposed cut detection technique performs a high-level feature extraction on the video frames, by applying a multi-scale image analysis approach combining nonlinear partial differential equations (PDE) to convolutional neural networks (CNN). A nonlinear second-order hyperbolic PDE model is proposed and its well-posedness is then investigated rigorously here. Its weak and unique solution is determined numerically applying a finite difference method-based numerical approximation algorithm that quickly converges to it. A scale-space representation is then created using that iterative discretization scheme. A CNN-based feature extraction is performed at each scale and the feature vectors obtained at multiple scales are concatenated into a final frame descriptor. The feature vector distance values between any two successive frames are then determined and the video transitions are identified next, by applying an automatic clustering scheme on these values. The proposed PDE model, its mathematical investigation and discretization, and the multi-scale analysis based on it represent the major contributions of this work. Some temporal segmentation experiments and method comparisons that illustrate the effectiveness of the proposed framework are finally described in this research paper.
Non-Parametric Non-Inferiority Assessment in a Three-Arm Trial with Non-Ignorable Missing Data
Authors: Li Wei , Zhang Yunqi , Tang Niansheng
Published: January 2023

A three-arm non-inferiority trial including a placebo is usually utilized to assess the non-inferiority of an experimental treatment to a reference treatment. Existing methods for assessing non-inferiority mainly focus on the fully observed endpoints. However, in some clinical trials, treatment endpoints may be subject to missingness for various reasons, such as the refusal of subjects or their migration. To address this issue, this paper aims to develop a non-parametric approach to assess the non-inferiority of an experimental treatment to a reference treatment in a three-arm trial with non-ignorable missing endpoints. A logistic regression is adopted to specify a non-ignorable missingness data mechanism. A semi-parametric imputation method is proposed to estimate parameters in the considered logistic regression. Inverse probability weighting, augmented inverse probability weighting and non-parametric methods are developed to estimate treatment efficacy for known and unknown parameters in the considered logistic regression. Under some regularity conditions, we show asymptotic normality of the constructed estimators for treatment efficacy. A bootstrap resampling method is presented to estimate asymptotic variances of the estimated treatment efficacy. Three Wald-type statistics are constructed to test the non-inferiority based on the asymptotic properties of the estimated treatment efficacy. Empirical studies show that the proposed Wald-type test procedure is robust to the misspecified missingness data mechanism, and behaves better than the complete-case method in the sense that the type I error rates for the former are closer to the pre-given significance level than those for the latter.
Product Convolution of Generalized Subexponential Distributions
Authors: Mikutavičius Gustas , Šiaulys Jonas
Published: January 2023

Assume that ξ and η are two independent random variables with distribution functions Fξ and Fη, respectively. The distribution of a random variable ξη, denoted by Fξ⊗Fη, is called the product-convolution of Fξ and Fη. It is proved that Fξ⊗Fη is a generalized subexponential distribution if Fξ belongs to the class of generalized subexponential distributions and η is nonnegative and not degenerated at zero.
Newton-Based Extremum Seeking for Dynamic Systems Using Kalman Filtering: Application to Anaerobic Digestion Process Control
Authors: Tian Yang , Pan Ning , Hu Maobo , Wang Haoping , Simeonov Ivan , Kabaivanova Lyudmila , Christov Nicolai
Published: January 2023

In this paper, a new Newton-based extremum-seeking control for dynamic systems is proposed using Kalman filter for gradient and Hessian estimation as well as a stochastic perturbation signal with time-varying amplitude. The obtained Kalman filter based Newton extremum-seeking control (KFNESC) makes it possible to accelerate the convergence to the extremum and attenuate the steady-state oscillations. The convergence and oscillation attenuation properties of the closed-loop system with KFNESC are considered, and the proposed control is applied to a two-stages anaerobic digestion process in order to maximize the hydrogen production rate, which has better robustness and a slower steady-state oscillation with the comparison of Newton-based ESC and sliding mode ESC.
Estimation of Coefficient of Variation Using Calibrated Estimators in Double Stratified Random Sampling
Authors: Shahzad Usman , Ahmad Ishfaq , García-Luengo Amelia V. , Zaman Tolga , Al-Noor Nadia H. , Kumar Anoop
Published: January 2023

One of the most useful indicators of relative dispersion is the coefficient of variation. The characteristics of the coefficient of variation have contributed to its widespread use in most scientific and academic disciplines, with real life applications. The traditional estimators of the coefficient of variation are based on conventional moments; therefore, these are highly affected by the presence of extreme values. In this article, we develop some novel calibration-based coefficient of variation estimators for the study variable under double stratified random sampling (DSRS) using the robust features of linear (L and TL) moments, which offer appropriate coefficient of variation estimates. To evaluate the usefulness of the proposed estimators, a simulation study is performed by using three populations out of which one is based on the COVID-19 pandemic data set and the other two are based on apple fruit data sets. The relative efficiency of the proposed estimators with respect to the existing estimators has been calculated. The superiority of the suggested estimators over the existing estimators are clearly validated by using the real data sets.
Estimating the Risk of Contracting COVID-19 in Different Settings Using a Multiscale Transmission Dynamics Model
Authors: Kanté Dramane Sam Idris , Jebrane Aissam , Bouchnita Anass , Hakim Abdelilah
Published: January 2023

Airborne transmission is the dominant route of coronavirus disease 2019 (COVID-19) transmission. The chances of contracting COVID-19 in a particular situation depend on the local demographic features, the type of inter-individual interactions, and the compliance with mitigation measures. In this work, we develop a multiscale framework to estimate the individual risk of infection with COVID-19 in different activity areas. The framework is parameterized to describe the motion characteristics of pedestrians in workplaces, schools, shopping centers and other public areas, which makes it suitable to study the risk of infection under specific scenarios. First, we show that exposure to individuals with peak viral loads increases the chances of infection by 99%. Our simulations suggest that the risk of contracting COVID-19 is especially high in workplaces and residential areas. Next, we determine the age groups that are most susceptible to infection in each location. Then, we show that if 50% of the population wears face masks, this will reduce the chances of infection by 8%, 32%, or 45%, depending on the type of the used mask. Finally, our simulations suggest that compliance with social distancing reduces the risk of infection by 19%. Our framework provides a tool that assesses the location-specific risk of infection and helps determine the most effective behavioral measures that protect vulnerable individuals.
Mathematics in Finite Element Modeling of Computational Friction Contact Mechanics 2021–2022
Authors: Pop Nicolae , Marin Marin , Vlase Sorin
Published: January 2023

In engineering practice, structures with identical components or parts are useful from several points of view: less information is needed to describe the system; designs can be conceptualized quicker and easier; components are made faster than during traditional complex assembly; and finally, the time needed to achieve the structure and the cost involved in manufacturing decrease. Additionally, the subsequent maintenance of this system then becomes easier and cheaper. The aim of this Special Issue is to provide an opportunity for international researchers to share and review recent advances in the finite element modeling of computational friction contact mechanics. Numerical modeling in mathematics, mechanical engineering, computer science, computers, etc. presents many challenges. The finite element method applied in solid mechanics was designed by engineers to simulate numerical models in order to reduce the design costs of prototypes, tests and measurements. This method was initially validated only by measurements but gave encouraging results. After the discovery of Sobolev spaces, the abovementioned results were obtained, and today, numerous researchers are working on improving this method. Some of applications of this method in solid mechanics include mechanical engineering, machine and device design, civil engineering, aerospace and automotive engineering, robotics, etc. Frictional contact is a complex phenomenon that has led to research in mechanical engineering, computational contact mechanics, composite material design, rigid body dynamics, robotics, etc. A good simulation requires that the dynamics of contact with friction be included in the formulation of the dynamic system so that an approximation of the complex phenomena can be made. To solve these linear or nonlinear dynamic systems, which often have non-differentiable terms, or discontinuities, software that considers these high-performance numerical methods and computers with high computing power are needed. This Special Issue is dedicated to this kind of mechanical structure and to describing the properties and methods of analysis of these structures. Discrete or continuous structures in static and dynamic cases are also considered. Additionally, theoretical models, mathematical methods and numerical analysis of these systems, such as the finite element method and experimental methods, are used in these studies. Machine building, automotive, aerospace and civil engineering are the main areas in which such applications appear, but they can also be found in most other engineering fields. With this Special Issue, we want to disseminate knowledge among researchers, designers, manufacturers and users in this exciting field.
Evaluation of the Fast Synchrophasors Estimation Algorithm Based on Physical Signals
Authors: Senyuk Mihail , Rajab Khairan , Safaraliev Murodbek , Kamalov Firuz
Published: January 2023

The goal of this study is to evaluate the performance of the fast algorithm for synchrophasor estimation proposed on the basis of a physical system. The test system is represented by a physical model of a power system with four synchronous generators (15 and 5 kVA). Three synchronous machines represent steam turbine generators, while the fourth machine represents a hydro generator. The proposed method of accuracy assessment is based on comparison of the original and the recovered signals, using values of amplitude and phase angle. The experiments conducted in the study include three-phase faults, two-phase faults and single-phase faults at various buses of the test model. Functional dependencies of initial signal standard deviation from the recovered signal are obtained, as well as those for sampling rate and window width. Based on the results, the following requirements for measurement system and window width are formulated: sampling rate of analog-to-digital converter should be 10 kHz; and window width should start from 5 ms. In addition, the fast algorithm of synchrophasor estimation was tested on event recorder signals. The sampling rate of these signals was 2 kHz. Acceptable window width for event recorder signals is 8 ms. The algorithm was implemented using programming language Python 3 for the testing purposes. The proposed fast algorithm of synchrophasor estimation can be applied in methods for emergency control and equipment state monitoring with short time response.
Assisting Glaucoma Screening Process Using Feature Excitation and Information Aggregation Techniques in Retinal Fundus Images
Authors: Raza Ali , Adnan Sharjeel , Ishaq Muhammad , Kim Hyung Seok , Naqvi Rizwan Ali , Lee Seung-Won
Published: January 2023

The rapidly increasing trend of retinal diseases needs serious attention, worldwide. Glaucoma is a critical ophthalmic disease that can cause permanent vision impairment. Typically, ophthalmologists diagnose glaucoma using manual assessments which is an error-prone, subjective, and time-consuming approach. Therefore, the development of automated methods is crucial to strengthen and assist the existing diagnostic methods. In fundus imaging, optic cup (OC) and optic disc (OD) segmentation are widely accepted by researchers for glaucoma screening assistance. Many research studies proposed artificial intelligence (AI) based decision support systems for glaucoma diagnosis. However, existing AI-based methods show serious limitations in terms of accuracy and efficiency. Variations in backgrounds, pixel intensity values, and object size make the segmentation challenging. Particularly, OC size is usually very small with unclear boundaries which makes its segmentation even more difficult. To effectively address these problems, a novel feature excitation-based dense segmentation network (FEDS-Net) is developed to provide accurate OD and OC segmentation. FEDS-Net employs feature excitation and information aggregation (IA) mechanisms for enhancing the OC and OD segmentation performance. FEDS-Net also uses rapid feature downsampling and efficient convolutional depth for diverse and efficient learning of the network, respectively. The proposed framework is comprehensively evaluated on three open databases: REFUGE, Drishti-GS, and Rim-One-r3. FEDS-Net achieved outperforming segmentation performance compared with state-of-the-art methods. A small number of required trainable parameters (2.73 million) also confirms the superior computational efficiency of our proposed method.
A Hybrid Multitask Learning Framework with a Fire Hawk Optimizer for Arabic Fake News Detection
Authors: Abd Elaziz Mohamed , Dahou Abdelghani , Orabi Dina Ahmed , Alshathri Samah , Soliman Eman M. , Ewees Ahmed A.
Published: January 2023

The exponential spread of news and posts related to the COVID-19 pandemic on social media platforms led to the emergence of the disinformation phenomenon. The phenomenon of spreading fake information and news creates significant concern for the public health and safety of the population. In this paper, we propose a disinformation detection framework based on multi-task learning (MTL) and meta-heuristic algorithms in the context of the COVID-19 pandemic. The developed framework uses an MTL and a pre-trained transformer-based model to learn and extract contextual feature representations from Arabic social media posts. The extracted contextual representations are fed to an alternative feature selection technique which depends on modified version of the Fire Hawk Optimizer. The proposed framework, which aims to improve the disinformation detection rate, was evaluated on several datasets of Arabic social media posts. The experimental results show that the proposed framework can achieve accuracy of 59%. It obtained, at best, precision, recall, and F-measure of 53%, 71%, and 53%, respectively, on all datasets; and it outperformed the other algorithms in all measures.
Thermal-Diffusive Processes of an Electron-Hole Non-Local Semiconductor Model with Variable Thermal Conductivity and Hall Current Effect
Authors: Alhashash Abeer , Raddadi Merfat H. , El-Bary Alaa A. , Chteoui Riadh , Mhemdi Abdelwaheb , Lotfy Khaled
Published: January 2023

In this work, a novel model is presented that describes thermal diffusion processes through non-local semiconductor materials. The material under study is subjected to the influence of a strong magnetic field, which creates a Hall current. Interference between the excited electrons and the excited holes of a non-local semiconductor that had been exposed to temperature was present, and thermal conductivity depending on changes in graduated temperature were accounted for. The governing equations are written in a dimensionless form in one dimension (1D) where the thermal conductivity is taken as a function of temperature through electronic and elastic deformation (ED and ED) processes. Laplace transforms in one dimension with initial conditions were used to convert partial differential equations to arrive at exact formulas of solutions. To obtain the exact linear solutions, some boundary conditions taken on the free surface of the non-local semiconductor were used. Using numerical methods of inverse Laplace transforms, the complete solutions of the physical quantities under study were obtained. To further understand how various variables (thermal memory, variable thermal conductivity, and Hall current) affect the non-local semiconductor, numerical physical fields were simulated, and are graphically depicted, and discussed herein.
Differential Evolution Based Numerical Variable Speed Limit Control Method with a Non-Equilibrium Traffic Model
Authors: Strnad Irena , Marsetič Rok
Published: January 2023

This paper introduces a numerical variable speed limit (VSL) control method on a motorway, modeled by the system of partial differential equations (PDEs) of a non- equilibrium continuum traffic model. The method consists of a macroscopic simulation (i.e., numerical solution of the system of PDEs of the continuum model), introduction of the solution-based cost function and numerical optimization with a differential evolution algorithm (DE). Due to the numerical solution scheme, the method enables application of a wide range of continuum traffic models without prior discretization of PDEs. In this way, the method overcomes the limitations of the basic continuum models and represents a step towards more accurate traffic modelling in control strategies. In this paper, we determine optimal variable speed limits with the DE algorithm on a motorway section modeled by the modified switching curve model, which is a non-equilibrium continuum model consistent with the three-phase traffic flow theory. The effectiveness of the determined variable speed limits is validated using microsimulations of the test section, which show promising reductions of queue lengths and number of stops.
A Case of a Malignant Lymphoma Patient Persistently Infected with SARS-CoV-2 for More than 6 Months
Authors: Nagasaki Yoji , Kadowaki Masanori , Nakamura Asako , Etoh Yoshiki , Shimo Masatoshi , Ishihara Sayoko , Arimizu Yoko , Iwamoto Rena , Kamamuta Seiji , Iwasaki Hiromi
Published: January 2023

Coronavirus disease 2019 (COVID-19) is an emerging infectious disease caused by severe acute respiratory syndrome 2 (SARS-CoV-2). There are many unknowns regarding the handling of long-term SARS-CoV-2 infections in immunocompromised patients. Here, we describe the lethal disease course in a SARS-CoV-2-infected patient during Bruton’s tyrosine kinase inhibitor therapy. We performed whole-genome analysis using samples obtained during the course of the disease in a 63-year-old woman who was diagnosed with intraocular malignant lymphoma of the right eye in 2012. She had received treatment since the diagnosis. An autologous transplant was performed in 2020, but she experienced a worsening of the primary disease 26 days before she was diagnosed with a positive SARS-CoV-2 RT-PCR. Tirabrutinib was administered for the primary disease. A cluster of COVID-19 infections occurred in the hematological ward while the patient was hospitalized, and she became infected on day 0. During the course of the disease, she experienced repeated remission exacerbations of COVID-19 pneumonia and eventually died on day 204. SARS-CoV-2 whole-viral sequencing revealed that the patient shed the virus long-term. Viral infectivity studies confirmed infectious virus on day 189, suggesting that the patient might be still infectious. This case report describes the duration and viral genetic evaluation of a patient with malignant lymphoma who developed SARS-CoV-2 infection during Bruton’s tyrosine kinase inhibitor therapy and in whom the infection persisted for over 6 months.
Estimation of CO2 Separation Performances through CHA-Type Zeolite Membranes Using Molecular Simulation
Authors: Hasegawa Yasuhisa , Natsui Mayumi , Abe Chie , Ikeda Ayumi , Lundin Sean-Thomas B.
Published: January 2023

Chabazite (CHA)-type zeolite membranes are a potential material for CO2 separations because of their small pore aperture, large pore volume, and low aluminum content. In this study, the permeation and separation properties were evaluated using a molecular simulation technique with a focus on improving the CO2 separation performance. The adsorption isotherms of CO2 and CH4 on CHA-type zeolite with Si/Al = 18.2 were predicted by grand canonical Monte Carlo, and the diffusivities in zeolite micropores were simulated by molecular dynamics. The CO2 separation performance of the CHA-type zeolite membrane was estimated by a Maxwell–Stefan equation, accounting for mass transfer through the support tube. The results indicated that the permeances of CO2 and CH4 were influenced mainly by the porosity of the support, with the CO2 permeance reduced due to preferential adsorption with increasing pressure drop. In contrast, it was important for estimation of the CH4 permeance to predict the amounts of adsorbed CH4. Using molecular simulation and the Maxwell–Stefan equation is shown to be a useful technique for estimating the permeation properties of zeolite membranes, although some problems such as predicting accurate adsorption terms remain.
The Effect of Fatigue Damage on the Corrosion Fatigue Crack Growth Mechanism in A7N01P-T4 Aluminum Alloy
Authors: Chen Wenjing , Lu Wei , Gou Guoqing , Dian Liwen , Zhu Zhongyin , Jin Junjun
Published: January 2023

A7N01P-T4 aluminum alloy plates for high-speed trains will experience a certain amount of fatigue damage under alternating loads. Three groups of samples, P0 (no fatigue damage), P1 (loading stress 30 MPa), and P2 (loading stress 70 MPa), were created, and corrosion fatigue crack growth (CFCG) tests were conducted in 3.5 wt.% NaC1 solution. The crack growth rate was found to increase after fatigue damage as the damage degree increased. In addition, the A7N01P-T4 aluminum alloy base metal exhibited obvious secondary cracks and crack bifurcations after fatigue damage. It is believed that fatigue damage causes stress concentration in the material, while a certain degree of stress corrosion cracking occurs during the CFCG growth process. This is because hydrogen (H) easily accumulates and diffuses along the grain boundary, which reduces the strength of the grain boundary, thereby becoming the preferred orientation for crack growth. This explains why the CFCG rate of the material is accelerated following fatigue damage to a certain extent.
Lipidomic Predictors of Coronary No-Reflow
Authors: Surendran Arun , Ismail Umar , Atefi Negar , Bagchi Ashim K. , Singal Pawan K. , Shah Ashish , Aliani Michel , Ravandi Amir
Published: January 2023

The ‘no-reflow’ phenomenon (NRP) after primary percutaneous coronary intervention (PCI) is a serious complication among acute ST-segment elevation myocardial infarction (STEMI) patients. Herein, a comprehensive lipidomics approach was used to quantify over 300 distinct molecular species in circulating plasma from 126 patients with STEMI before and after primary PCI. Our analysis showed that three lipid classes: phosphatidylcholine (PC), alkylphosphatidylcholine (PC(O)), and sphingomyelin (SM), were significantly elevated (p < 0.05) in no-reflow patients before primary PCI. The levels of individual fatty acids and total fatty acid levels were significantly lower (p < 0.05) in no-reflow subjects after PCI. The grouping of patients based on ECG ST-segment resolution (STR) also demonstrated the same trend, confirming the possible role of these differential lipids in the setting of no-reflow. Sphingomyelin species, SM 41:1 and SM 41:2, was invariably positively correlated with corrected TIMI frame count (CTFC) at pre-PCI and post-PCI. The plasma levels of SM 42:1 exhibited an inverse association (p < 0.05) consistently with tumor necrosis factor-alpha (TNF-α) at pre-PCI and post-PCI. In conclusion, we identified plasma lipid profiles that distinguish individuals at risk of no-reflow and provided novel insights into how dyslipidemia may contribute to NRP after primary PCI.
A Non-Contact Fall Detection Method for Bathroom Application Based on MEMS Infrared Sensors
Authors: He Chunhua , Liu Shuibin , Zhong Guangxiong , Wu Heng , Cheng Lianglun , Lin Juze , Huang Qinwen
Published: January 2023

The ratio of the elderly to the total population around the world is larger than 10%, and about 30% of the elderly are injured by falls each year. Accidental falls, especially bathroom falls, account for a large proportion. Therefore, fall events detection of the elderly is of great importance. In this article, a non-contact fall detector based on a Micro-electromechanical Systems Pyroelectric Infrared (MEMS PIR) sensor and a thermopile IR array sensor is designed to detect bathroom falls. Besides, image processing algorithms with a low pass filter and double boundary scans are put forward in detail. Then, the statistical features of the area, center, duration and temperature are extracted. Finally, a 3-layer BP neural network is adopted to identify the fall events. Taking into account the key factors of ambient temperature, objective, illumination, fall speed, fall state, fall area and fall scene, 640 tests were performed in total, and 5-fold cross validation is adopted. Experimental results demonstrate that the averages of the precision, recall, detection accuracy and F1-Score are measured to be 94.45%, 90.94%, 92.81% and 92.66%, respectively, which indicates that the novel detection method is feasible. Thereby, this IOT detector can be extensively used for household bathroom fall detection and is low-cost and privacy-security guaranteed.
3D Printed Chitosan/Alginate Hydrogels for the Controlled Release of Silver Sulfadiazine in Wound Healing Applications: Design, Characterization and Antimicrobial Activity
Authors: Bergonzi Carlo , Bianchera Annalisa , Remaggi Giulia , Ossiprandi Maria Cristina , Bettini Ruggero , Elviri Lisa
Published: January 2023

The growing demand for personalized medicine requires innovation in drug manufacturing to combine versatility with automation. Here, three-dimensional (3D) printing was explored for the production of chitosan (CH)/alginate (ALG)-based hydrogels intended as active dressings for wound healing. ALG hydrogels were loaded with 0.75% w/v silver sulfadiazine (SSD), selected as a drug model commonly used for the therapeutic treatment of infected burn wounds, and four different 3D CH/ALG architectures were designed to modulate the release of this active compound. CH/ALG constructs were characterized by their water content, elasticity and porosity. ALG hydrogels (Young’s modulus 0.582 ± 0.019 Mpa) were statistically different in terms of elasticity compared to CH (Young’s modulus 0.365 ± 0.015 Mpa) but very similar in terms of swelling properties (water content in ALG: 93.18 ± 0.88% and in CH: 92.76 ± 1.17%). In vitro SSD release tests were performed by using vertical diffusion Franz cells, and statistically significant different behaviors in terms of the amount and kinetics of drugs released were observed as a function of the construct. Moreover, strong antimicrobial potency (100% of growth inhibition) against Staphylococcus aureus and Pseudomonas aeruginosa was demonstrated depending on the type of construct, offering a proof of concept that 3D printing techniques could be efficiently applied to the production of hydrogels for controlled drug delivery.
An Insight into Goat Cheese: The Tales of Artisanal and Industrial Gidotyri Microbiota
Authors: Nelli Aikaterini , Venardou Brigkita , Skoufos Ioannis , Voidarou Chrysoula (Chrysa) , Lagkouvardos Ilias , Tzora Athina
Published: January 2023

The purpose of this study was to determine for the first time the microbiota in artisanal-type and industrial-type Gidotyri cheeses and investigate the influence of the cheese-making practices on their composition using culture-independent techniques. The microbiota present in artisanal with commercial starters (Artisanal_CS, n = 15), artisanal with in-house starters (Artisanal_IHS, n = 10) and industrial (Ind., n = 9) Gidotyri cheese samples were analyzed using a targeted metagenomic approach (16S rRNA gene). The Ind. Gidotyri cheese microbiota were less complex, dominated by the Streptococcaceae family (91%) that was more abundant compared to the artisanal Gidotyri cheeses (p < 0.05). Artisanal cheeses were more diverse compositionally with specific bacterial species being prevalent to each subtype. Particularly, Loigolactobacillus coryniformis (OTU 175), Secundilactobacillus malefermentans (OTU 48), and Streptococcus parauberis (OTU 50) were more prevalent in Artisanal_IHS cheeses compared to Artisanal_CS (p ≤ 0.001) and Ind. (p < 0.01) Gidotyri cheeses. Carnobacterium maltaromaticum (OTU 23) and Enterobacter hormaechei subsp. hoffmannii (OTU 268) were more prevalent in Artisanal_CS cheeses compared to Artisanal_IHS cheeses (p < 0.05) and Ind. cheeses (p < 0.05). Hafnia alvei (OTU 13) and Acinetobacter colistiniresistens (OTU 111) tended to be more prevalent in Artisanal_CS compared to the other two cheese groups (p < 0.10). In conclusion, higher microbial diversity was observed in the artisanal-type Gidotyri cheeses, with possible bacterial markers specific to each subtype identified with potential application to traceability of the manufacturing processes’ authenticity and cheese quality.
A Randomized Large-Scale Cross-Sectional Serological Survey of Hepatitis E Virus Infection in Belgian Pig Farms
Authors: Wielick Constance , Ludwig-Begall Louisa , Faes Christel , Ribbens Stefaan , Saegerman Claude , Thiry Etienne
Published: January 2023

Hepatitis E virus (HEV) is the causative agent of hepatitis E disease in humans. While sporadic HEV infections, which occur in industrialised countries and are typically due to HEV genotypes 3 or 4, are asymptomatic and self-limiting, a chronic form of the disease can lead to liver cirrhosis in immunocompromised individuals. Pigs share HEV 3 and 4 genotypes and are thus considered a major animal reservoir for human infection. A subset of animals has been shown to carry HEV particles at the age of slaughter, rendering raw or undercooked pig products potential vectors for human infection. To provide an overview of the current dissemination of HEV in Belgian pig herds, this study was designed as a randomized, robust, large-scale, cross-sectional, serological survey. HEV genotypes and subtypes recently circulating in Belgium (2020–2021) were investigated. Sample stratification as well as epidemiological investigation through the available demographic data of the sampled herds showed that HEV widely circulated in the Belgian pig population during this time and that a change in the circulating HEV strains may have occurred in the last decade. Herd size and type were identified as risk factors for HEV herd-seropositivity. Identifying farms at risk of being HEV-positive is an important step in controlling HEV spread and human infection.
Taxonomic Study of Three Novel Paenibacillus Species with Cold-Adapted Plant Growth-Promoting Capacities Isolated from Root of Larix gmelinii
Authors: Xue Han , Tu Yan , Ma Tengfei , Jiang Ning , Piao Chungen , Li Yong
Published: January 2023

Exploration of the novel species of the genus Paenibacillus with plant-growth promoting characteristics at the low-temperature environment is of great significance for the development of psychrotolerant biofertilizer in forestry and agriculture. During the course of isolation of root endophytes of Larix gmelinii in the island frozen soil, three strains designated as T3-5-0-4, N1-5-1-14 and N5-1-1-5 were isolated. The three strains showed plant growth-promoting properties at the low temperature, such as phosphate solubilization, indole-3-acetic acid biosynthesis and siderophore production. According to pairwise sequence analyses of the 16S rRNA genes, the three strains represent putatively novel taxa within the genus Paenibacillus. The strains have typical chemotaxonomic characteristics of the genus Paenibacillus by having meso-diaminopimelic acid as diagnostic diamino acid, anteiso-C15:0 as the predominant fatty acid and MK-7 as the predominant menaquinone. The polar lipid profiles of all strains contained diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The sizes of the genomes of the stains ranged from 5.66 to 9.07 Mb and the associated G+C contents ranged from 37.9% to 44.7%. Polyphasic taxonomic study including determination of genome relatedness indices revealed that the strains are representatives of three novel species in the genus Paenibacillus. Consequently, isolates T3-5-0-4, N1-5-1-14 and N5-1-1-5 are proposed as novel species for which the names of Paenibacillus endoradicis sp. nov. (CFCC15691T = KCTC43441T), Paenibacillus radicibacter sp. nov, (CFCC15694T = KCTC43442T) and Paenibacillus radicis sp. nov. (CFCC15710T = KCTC43173T), respectively. Moreover, analysis for biosynthetic genes showed that the strains have potential for plant growth-promoting characteristics, plant rhizospheres colonization and low-temperature adaption, most of which are consistent with the results of the bioactivity test.
Aluminium(III) Oxide—The Silent Killer of Bacteria
Authors: Schabikowski Mateusz , Kowalczyk Paweł , Karczmarska Agnieszka , Gawdzik Barbara , Wypych Aleksandra , Kramkowski Karol , Wrzosek Karol , Laskowski Łukasz
Published: January 2023

In this article, we describe the antimicrobial properties of pristine anodised aluminium oxide matrices—the material many consider biologically inert. During a typical anodisation process, chromium and chlorine compounds are used for electropolishing and the removal of the first-step aluminium oxide. Matrices without the use of those harmful compounds were also fabricated and tested for comparison. The antibacterial tests were conducted on four strains of Escherichia coli: K12, R2, R3 and R4. The properties of the matrices were also compared to the three types of antibiotics: ciprofloxacin, bleomycin and cloxacillin using the Minimal Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. Moreover, DNA was isolated from the analysed bacteria which was additionally digested with formamidopyrimidine-DNA glycosylase (Fpg) protein from the group of repair glycosases. These enzymes are markers of modified oxidised bases in nucleic acids produced during oxidative stress in cells. Preliminary cellular studies, MIC and MBC tests and digestion with Fpg protein after modification of bacterial DNA suggest that these compounds may have greater potential as antibacterial agents than the aforementioned antibiotics. The described composites are highly specific for the analysed model Escherichia coli strains and may be used in the future as new substitutes for commonly used antibiotics in clinical and nosocomial infections in the progressing pandemic era. The results show much stronger antibacterial properties of the functionalised membranes on the action of bacterial membranes in comparison to the antibiotics in the Fpg digestion experiment. This is most likely due to the strong induction of oxidative stress in the cell through the breakdown of the analysed bacterial DNA.
Cardioprotective Effect of Centaurea castriferrei Borbás & Waisb Extract against Doxorubicin-Induced Cardiotoxicity in H9c2 Cells
Authors: Humeniuk Ewelina , Adamczuk Grzegorz , Kubik Joanna , Adamczuk Kamila , Józefczyk Aleksandra , Korga-Plewko Agnieszka
Published: January 2023

Doxorubicin (DOX) is one of the most used chemotherapeutic agents in the treatment of various types of cancer. However, a continual problem that is associated with its application in therapeutic regimens is the development of dose-dependent cardiotoxicity. The progression of this process is associated with a range of different mechanisms, but especially with the high level of oxidative stress. The aim of the study was to evaluate the effects of the water and methanol–water extracts from the plant Centaurea castriferrei (CAS) obtained by the ultrasound-assisted extraction method on the DOX-induced cardiotoxicity in the rat embryonic cardiomyocyte cell line H9c2. The H9c2 cells were treated for 48 h with the DOX and water or methanol–water extracts, or a combination (DOX + CAS H2O/CAS MeOH). The MTT assay, cell cycle analysis, and apoptosis detection revealed that both the tested extracts significantly abolished the cytotoxic effect caused by DOX. Moreover, the detection of oxidative stress by the CellROX reagent, the evaluation of the number of AP sites, and the expressions of the genes related to the oxidative stress defense showed substantial reductions in the oxidative stress levels in the H9c2 cells treated with the combination of DOX and CAS H2O/CAS MeOH compared with the DOX administered alone. The tested extracts did not affect the cytotoxic effect of DOX on the MCF-7 breast cancer cell line. The obtained results constitute the basis for further research in the context of the application of C. castriferrei extracts as adjuvants in the therapy regiments of cancer patients treated with DOX.
Interaction of Bis-(sodium-sulfopropyl)-Disulfide and Polyethylene Glycol on the Copper Electrodeposited Layer by Time-of-Flight Secondary-Ion Mass Spectrometry
Authors: Mroczka Robert , Słodkowska Agnieszka , Ładniak Agata , Chrzanowska Agnieszka
Published: January 2023

The interactions of the functional additives SPS (bis-(sodium-sulfopropyl)-disulfide) and polyethylene glycol (PEG) in the presence of chloride ions were studied by time-of-flight secondary-ion mass spectrometry (TOF-SIMS) in combination with cyclic voltammetry measurements (CV). The PEG, thiolate, and chloride surface coverages were estimated and discussed in terms of their electrochemical suppressing/accelerating abilities. The conformational influence of both the gauche/trans thiolate molecules, as well as around C-C and C-O of PEG, on the electrochemical properties were discussed. The contribution of the hydrophobic interaction of -CH2-CH2- of PEG with chloride ions was only slightly reduced after the addition of SPS, while the contribution of Cu-PEG adducts diminished strongly. SPS and PEG demonstrated significant synergy by significant co-adsorption. It was shown that the suppressing abilities of PEG that rely on forming stable Cu-PEG adducts, identified in the form C2H4O2Cu+ and C3H6OCu+, were significantly reduced after the addition of SPS. The major role of thiolate molecules adsorbed on a copper surface in reducing the suppressing abilities of PEG rely on the efficient capture of Cu2+ ions, diminishing the available copper ions for the ethereal oxygen of PEG.
Thermodynamic and Kinetic Investigation of the Adsorption and Desorption of Trimethoprim and Its Main Metabolites in Mediterranean Crop Soils
Authors: Mejías Carmen , Santos Juan Luis , Martín Julia , Aparicio Irene , Alonso Esteban
Published: January 2023

The adsorption–desorption processes of organic pollutants into the soil are one of the main factors influencing their potential environmental risks and distribution in the environment. In the present work, the adsorption–desorption behavior of an antibiotic, trimethoprim (TMP), and two of its main metabolites, 3-desmethyltrimethoprim (DM-TMP) and 4-hydroxytrimethoprim (OH-TMP), were assessed in three Mediterranean agricultural soils with different physicochemical characteristics. Results showed that the adsorption kinetic is performed in two steps: external sorption and intraparticle diffusion. The adsorptions of the studied compounds in soils were similar and fitted to the three models but were better fitted to a linear model. In the case of DM-TMP and OH-TMP, their adsorptions were positively correlated with the soil organic matter. In addition, desorption was higher in less organic matter soil (from 1.3 to 30.9%). Furthermore, the desorptions measured for the TMP metabolites were lower than those measured in the case of TMP (from 2.0 and 4.0% for OH-TMP and DM-TMP, respectively, to 9.0% for TMP).
Alkyl Levulinates and 2-Methyltetrahydrofuran: Possible Biomass-Based Solvents in Palladium-Catalyzed Aminocarbonylation
Authors: Uzunlu Nuray , Pongrácz Péter , Kollár László , Takács Attila
Published: January 2023

In this research, ethyl levulinate, methyl levulinate, and 2-methyltetrahydrofuran as bio-derived hemicellulose-based solvents were applied as green alternatives in palladium-catalyzed aminocarbonylation reactions. Iodobenzene and morpholine were used in optimization reactions under different conditions, such as temperatures, pressures, and ligands. It was shown that the XantPhos ligand had a great influence on conversion (98%) and chemoselectivity (100% carboxamide), compared with the monodentate PPh3. Following this study, the optimized conditions were used to extend the scope of substrates with nineteen candidates (various para-, ortho-, and meta-substituted iodobenzene derivatives and iodo-heteroarenes), as well as eight different amine nucleophiles.
Polymorphic Covalent Organic Frameworks: Molecularly Defined Pore Structures and Iodine Adsorption Property
Authors: Wang Canran , Jiang Shan , Ma Wenyue , Liu Zhaoyang , Liu Leijing , Zou Yongcun , Xu Bin , Tian Wenjing
Published: January 2023

Radioactive iodine-capturing materials are urgently needed for the emerging challenges in nuclear waste disposal. The various pore structures of covalent organic frameworks (COFs) render them promising candidates for efficient iodine adsorption. However, the detailed structure–property relationship of COFs in iodine adsorption remains elusive. Herein, two polymorphic COFs with significantly different crystalline structures are obtained based on the same building blocks with varied molecular ratios. The two COFs both have high crystallinity, high specific surface area, and excellent chemical and thermal stability. Compared with the [C4+C4] topology (PyT-2) with an AA stacking form, the [C4+C2] topology (PyT-1) with an AB stacking form has more twisted pore channels and complex ink-bottle pores. At ambient conditions, PyT-1 and PyT-2 both exhibit good adsorption properties for iodine capture either in a gaseous or liquid medium. Remarkably, PyT-1 presents an excellent maximum adsorption capacity (0.635 g g−1), and the adsorption limit of PyT-2 is 0.445 g g−1 in an n-hexane solution with an iodine concentration of 400 mg L−1, which is highly comparable to the state-of-the-art iodine absorption performance. This study provides a guide for the future molecular design strategy toward novel iodine adsorbents.
A New Approach to the Synthesis of Nanocrystalline Cobalt Boride in the Course of the Thermal Decomposition of Cobalt Complexes [Co(DMF)6]2+ with Boron Cluster Anions
Authors: Malinina Elena A. , Myshletsov Ivan I. , Buzanov Grigorii A. , Kubasov Alexey S. , Kozerozhets Irina V. , Goeva Lyudmila V. , Nikiforova Svetlana E. , Avdeeva Varvara V. , Zhizhin Konstantin Yu. , Kuznetsov Nikolay T.
Published: January 2023

In the course of the study, nanocrystalline cobalt monoboride was prepared by thermal decomposition of precursors [Co(DMF)6][An], where [An] = [B12H12]2− (1), [trans-B20H18]2− (2) or [B10Cl10]2− (3) in an argon atmosphere. Three new salt-like compounds 1–3 were prepared when Co(NO3)2 was allowed to react with (Et3NH)2[An]. Compound 1 is new; the structures of compounds 2 and 3 have been previously reported. Samples 1–3 were annealed at 900 °C in argon to form samples 1a–3a, which were characterized by single crystal XRD for 1 and powder XRD for 1–3. Powder XRD on the products showed the formation of BN and CoB for 1a in a 1:1 ratio; 2a gave a higher CoB:BN ratio but an overall decreased crystallinity. For 3a, only CoB was found. IR spectra of samples 1a–3a as well as X-ray spectral fluorescence analysis for 3a confirmed these results. The nanoparticular character of the decomposition products 1a–3a was shown using TEM; quite small particle sizes of about 10–15 nm and a quite normal size distribution were found for 1a and 2a, while the decomposition of 3 gave large particles with 200–350 nm and a broad distribution.
Z-Scheme CuOx/Ag/TiO2 Heterojunction as Promising Photoinduced Anticorrosion and Antifouling Integrated Coating in Seawater
Authors: Guo Xiaomin , Pan Guotao , Fang Lining , Liu Yan , Rui Zebao
Published: January 2023

In the marine environment, steel materials usually encounter serious problems with chemical or electrochemical corrosion and fouling by proteins, bacteria, and other marine organisms. In this work, a green bifunctional Z-scheme CuOx/Ag/P25 heterostructure coating material was designed to achieve the coordination of corrosion prevention and antifouling by matching the redox potential of the reactive oxygen species and the corrosion potential of 304SS. When CuOx/Ag/P25 heterostructure was coupled with the protected metal, the open circuit potential under illumination negatively shifted about 240 mV (vs. Ag/AgCl) and the photoinduced current density reached 16.6 μA cm−2. At the same time, more reactive oxygen species were produced by the Z-shape structure, and then the photocatalytic sterilization effect was stronger. Combined with the chemical sterilization of Ag and the oxide of Cu, the bacterial survival rate of CuOx/Ag/P25 was low (0.006%) compared with the blank sample. This design provides a strategy for developing green dual-functional coating materials with photoelectrochemical anticorrosion and antifouling properties.