bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Low Amperage Electric Current on Staphylococcus Aureus—Strategy for Combating Bacterial Biofilms Formation on Dental Implants in Cystic Fibrosis Patients, In Vitro Study
Authors: Minkiewicz-Zochniak Anna , Strom Kamila , Jarzynka Sylwia , Iwańczyk Bartłomiej , Koryszewska-Bagińska Anna , Olędzka Gabriela
Published: October 2021

Cystic fibrosis is an inherited disease that affects multiple organs and systems. The oral cavity can serve as a substantial source of bacteria, causing respiratory infections and diseases which continue to dictate the clinical course of the disease and prognosis in patients with CF. Low voltage and electric current could effectively kill bacteria and biofilms, and the activity of milliampere currents could be used as an effective method of fighting bacteria. This study evaluated the effect of low amperage electric current on the formation of Staphylococcus aureus biofilms on dental implants such as titanium and zirconium in patients with cystic fibrosis. Our studies suggest that a constant electric current at a low intensity of 1 mA and 10 mA is inhibiting bacterial adhesion, detaching biofilm-forming bacteria on biomaterials used in dental implants such as titanium and zirconium, and destroying bacterial cells of Staphylococcus aureus strains. In addition, we observed the selection of an appropriate biomaterial for implants in people affected by chronic diseases, such as CF, should be carefully planned.
Toward Eliminating Discontinuous Yielding Behavior of the EA4T Steel
Authors: Chen Jian-Zhi , Du Qin , Zhang Guang-Ping , Zhang Bin
Published: October 2021

Cold-rolled EA4T steel was heat-treated by inter-critical holding at 755 °C for 90, 120, 180, and 240 s, respectively, and then quenching in water. The tensile testing results of the EA4T specimens show an evident transition from the discontinuous yielding to the continuous yielding of the steel specimens by prolonging the holding time. A novel relationship between the discontinuous yielding behavior of tensile-deformed steel specimens and the carbide size was proposed based on experimental results and Cottrell’s theory. The model may provide a new clue for avoiding discontinuous yielding and improving mechanical properties of metals with static strain aging behaviors.
A Review of Finite Element Analysis and Artificial Neural Networks as Failure Pressure Prediction Tools for Corroded Pipelines
Authors: Vijaya Kumar Suria Devi , Lo Yin Kai Michael , Arumugam Thibankumar , Karuppanan Saravanan
Published: October 2021

This paper discusses the capabilities of artificial neural networks (ANNs) when integrated with the finite element method (FEM) and utilized as prediction tools to predict the failure pressure of corroded pipelines. The use of conventional residual strength assessment methods has proven to produce predictions that are conservative, and this, in turn, costs companies by leading to premature maintenance and replacement. ANNs and FEM have proven to be strong failure pressure prediction tools, and they are being utilized to replace the time-consuming methods and conventional codes. FEM is widely used to evaluate the structural integrity of corroded pipelines, and the integration of ANNs into this process greatly reduces the time taken to obtain accurate results.
Investigation of the 0.4C-35Cr-45Ni-Nb Alloy after Service in High-Temperature Steam and Hydrocarbons Environment
Authors: Orlikowski Juliusz , Szociński Michał , Zygmuntowicz Janusz , Gajewski Gabriel , Filipkowski Wojciech , Darowicki Kazimierz
Published: October 2021

The paper presents the results of investigation of the 0.4C-35Cr-45Ni-Nb alloy, which operated in the cracked hydrocarbon feeds and dilution steam at 1125 °C. The material originated from the pyrolytic furnace coil tubes, of which internal walls were in contact with the aforementioned medium, whereas the external walls were in contact with the flue gases. The examination included metallographic and mechanical tests on the material after service exposure, the results of which were compared with the ones obtained for the as-received non-exposed specimens. The metallographic tests revealed changes in the alloy’s structure manifested by formation of significant amount of the carbides due to carburization of the alloy from the steam and cracked hydrocarbon feeds side. The central and external parts of the alloy samples (having no contact with the process medium) underwent substantial degradation but within a relatively narrow zone of the material. The investigations of hydrogen and methane content in the alloy showed a high amount of these gases, resulting from high-temperature corrosion in steam environment. The mechanical tests demonstrated clear shortening of the plastic deformation range of the alloy due to penetration of the gases and formation of the carbides inside the material’s structure. A low level of corrosion and no creep mechanism were detected.
Structure and Properties of Ti/Ti64 Graded Material Manufactured by Laser Powder Bed Fusion
Authors: Borisov Evgenii , Polozov Igor , Starikov Kirill , Popovich Anatoly , Sufiiarov Vadim
Published: October 2021

Multimaterial additive manufacturing is an attractive way of producing parts with improved functional properties by combining materials with different properties within a single part. Pure Ti provides a high ductility and an improved corrosion resistance, while the Ti64 alloy has a higher strength. The combination of these alloys within a single part using additive manufacturing can be used to produce advanced multimaterial components. This work explores the multimaterial Laser Powder Bed Fusion (L-PBF) of Ti/Ti64 graded material. The microstructure and mechanical properties of Ti/Ti64-graded samples fabricated by L-PBF with different geometries of the graded zones, as well as different effects of heat treatment and hot isostatic pressing on the microstructure of the bimetallic Ti/Ti64 samples, were investigated. The transition zone microstructure has a distinct character and does not undergo significant changes during heat treatment and hot isostatic pressing. The tensile tests of Ti/Ti64 samples showed that when the Ti64 zones were located along the sample, the ratio of cross-sections has a greater influence on the mechanical properties than their shape and location. The presented results of the investigation of the graded Ti/Ti64 samples allow tailoring properties for the possible applications of multimaterial parts.
Enabling Conducting Polymer Applications: Methods for Achieving High Molecular Weight in Chemical Oxidative Polymerization in Alkyl- and Ether-Substituted Thiophenes
Authors: Hebert David D. , Naley Michael A. , Cunningham Carter C. , Sharp David J. , Murphy Emma E. , Stanton Venus , Irvin Jennifer A.
Published: October 2021

Polythiophenes (PTs) constitute a diverse array of promising materials for conducting polymer applications. However, many of the synthetic methods to produce PTs have been optimized only for the prototypical alkyl-substituted example poly(3-hexylthiophene) (P3HT). Improvement of these methods beyond P3HT is key to enabling the widespread application of PTs. In this work, P3HT and two ether-substituted PTs poly(2-dodecyl-2H,3H-thieno[3,4-b][1,4]dioxine) (PEDOT-C12) and poly(3,4-bis(hexyloxy)thiophene) (PBHOT) are synthesized by the FeCl3-initiated oxidative method under different conditions. Polymerization was carried out according to a common literature procedure (“reverse addition”) and a modified method (“standard addition”), which differ by the solvent system and the order of addition of reagents to the reaction mixture. Gel-permeation chromatography (GPC) was performed to determine the impact of the different methods on the molecular weights (Mw) and degree of polymerization (Xw) of the polymers relative to polystyrene standards. The standard addition method produced ether-substituted PTs with higher Mw and Xw than those produced using the reverse addition method for sterically unhindered monomers. For P3HT, the highest Mw and Xw were obtained using the reverse addition method. The results show the oxidation potential of the monomer and solution has the greatest impact on the yield and Xw obtained and should be carefully considered when optimizing the reaction conditions for different monomers.
Theoretical Study of N-Heterocyclic-Carbene–ZnX2 (X = H, Me, Et) Complexes
Authors: Jabłoński Mirosław
Published: October 2021

This article discusses the properties of as many as 30 carbene–ZnX2 (X = H, Me, Et) complexes featuring a zinc bond C⋯Zn. The group of carbenes is represented by imidazol-2-ylidene and its nine derivatives (labeled as IR), in which both hydrogen atoms of N-H bonds have been substituted by R groups with various spatial hindrances, from the smallest Me, iPr, tBu through Ph, Tol, and Xyl to the bulkiest Mes, Dipp, and Ad. The main goal is to study the relationship between type and size of R and X and both the strength of C⋯Zn and the torsional angle of the ZnX2 plane with respect to the plane of the imidazol-2-ylidene ring. Despite the considerable diversity of R and X, the range of dC⋯Zn is quite narrow: 2.12–2.20 Å. On the contrary, D0 is characterized by a fairly wide range of 18.5–27.4 kcal/mol. For the smallest carbenes, the ZnX2 molecule is either in the plane of the carbene or is only slightly twisted with respect to it. The twist angle becomes larger and more varied with the bulkier R. However, the value of this angle is not easy to predict because it results not only from the presence of steric effects but also from the possible presence of various interatomic interactions, such as dihydrogen bonds, tetrel bonds, agostic bonds, and hydrogen bonds. It has been shown that at least some of these interactions may have a non-negligible influence on the structure of the IR–ZnX2 complex. This fact should be taken into account in addition to the commonly discussed R⋯X steric repulsion.
Metal-Formate Framework Stiffening and Its Relevance to Phase Transition Mechanism
Authors: Peksa Paulina , Trzmiel Justyna , Ptak Maciej , Ciupa-Litwa Aneta , Sieradzki Adam
Published: October 2021

In the last decade, one of the most widely examined compounds of motal-organic frameworks was undoubtedly ((CH3)2NH2)(Zn(HCOO)3), but the problem of the importance of framework dynamics in the order–disorder phase change of the mechanism has not been fully clarified. In this study, a combination of temperature-dependent dielectric, calorimetric, IR, and Raman measurements was used to study the impact of ((CH3)2NH2)(Zn(DCOO)3) formate deuteration on the phase transition mechanism in this compound. This deuteration led to the stiffening of the metal-formate framework, which in turn caused an increase in the phase transition temperature by about 5 K. Interestingly, the energetic ordering of DMA+ cations remained unchanged compared to the non-deuterated compound.
The Comparative Analysis of the Coatings Deposited on the Automotive Parts by the Cataphoresis Method
Authors: Skotnicki Wojciech , Jędrzejczyk Dariusz
Published: October 2021

The paper presents preliminary research focused on the determination of the influence of surface preparation on the quality of the paint coating obtained by the cataphoresis method (KTL). The tests were carried out on steel parts used in the construction of trailers and truck bodies. The first research group consisted of cold-rolled and chemically cleaned parts, the second group were mechanically cleaned with abrasive blasting. In order to determine the influence of surface treatment on the corrosion resistance of the tested coatings, besides a corrosion test, roughness measurements were also carried out. Tests were performed on the crude surface and after coating deposition. Moreover, tests were supplemented by measuring the thickness of the coating using the magnetic induction method and the hardness with the use micro and nano hardness testers. Measurements of the tribological parameters under dry friction conditions were performed using a T11 tester. The corrosion resistance of the applied coatings was determined in a salt spray test. The obtained results were compared to those that were determined for different zinc coatings. It has been shown that the method of base steel surface preparation affects every measured parameter and property of tested paint coatings. The quality of the coating deposited on the steel base after chemical cleaning is much better than the one applied to the sandblasted surface. The measured corrosion resistance of the tested paint coatings is only greater than the corrosion resistance of the lamellar zinc coating. The other zinc coatings (galvanic, hot-dip, sherardized) show corrosion resistance by an order of magnitude higher.
A 1D–3D Approach for Fast Numerical Analysis of the Flow Characteristics of a Diesel Engine Exhaust Gas
Authors: Kong Kyeong-Ju
Published: October 2021

It is necessary to analyze the intake/exhaust gas flow of a diesel engine when turbocharger matching and when installing emission control devices such as exhaust gas recirculation (EGR), selective catalytic reduction (SCR), and scrubbers. Analyzing the intake/exhaust gas flow using a 3D approach can use various analytical models, but it requires a significant amount of time to perform the computation. An approach that combines 1D and 3D is a fast numerical analysis method that can utilize the analysis models of the 3D approach and obtain accurate calculation results. In this study, the flow characteristics of the exhaust gas were analyzed using a 1D–3D coupling algorithm to analyze the unsteady gas flow of a diesel engine, and whether the 1D–3D approach was suitable for analyzing exhaust systems was evaluated. The accuracy of the numerical analysis results was verified by comparison with the experimental results, and the flow characteristics of various shapes of the exhaust system of a diesel engine could be analyzed. Numerical analysis using the 1D–3D approach was able to be computed about 300 times faster than the 3D approach, and it was a method that could be used for research focused on the exhaust system. In addition, since it could quickly and accurately calculate intake/exhaust gas flow, it was expected to be used as a numerical analysis method suitable for analyzing the interaction of diesel engines with emission control devices and turbochargers.
Multigranulation Roughness of Intuitionistic Fuzzy Sets by Soft Relations and Their Applications in Decision Making
Authors: Anwar Muhammad , Bashir Shahida , Shabir Muhammad , Alharbi Majed
Published: October 2021

Multigranulation rough set (MGRS) based on soft relations is a very useful technique to describe the objectives of problem solving. This MGRS over two universes provides the combination of multiple granulation knowledge in a multigranulation space. This paper extends the concept of fuzzy set Shabir and Jamal in terms of an intuitionistic fuzzy set (IFS) based on multi-soft binary relations. This paper presents the multigranulation roughness of an IFS based on two soft relations over two universes with respect to the aftersets and foresets. As a result, two sets of IF soft sets with respect to the aftersets and foresets are obtained. These resulting sets are called lower approximations and upper approximations with respect to the aftersets and with respect to the foresets. Some properties of this model are studied. In a similar way, we approximate an IFS based on multi-soft relations and discuss their some algebraic properties. Finally, a decision-making algorithm has been presented with a suitable example.
Teachers’ Mathematics Knowledge for Teaching Early Algebra: A Systematic Review from the MKT Perspective
Authors: Pincheira Nataly , Alsina Ángel
Published: October 2021

The mathematical knowledge for teaching (MKT) model emerged from the advances proposed by Shulman in 1986 and 1987 as part of the teacher’s professional knowledge model, and refers to the mathematical knowledge that the teacher employs to carry out the instruction process in the classroom. MKT has become an international benchmark for research into mathematics education and boasts a great scope and impact to date. The objective of this study is to conduct a systematic review of the way in which the MKT of early algebra teachers has been conceptualized and empirically studied in the scientific literature from 2010 to 2021. A systematic search in the Web of Science and Scopus databases led to a review of 17 papers. The results show great advances in the conceptualization of mathematical knowledge for teaching early algebra, focusing mainly on primary education teachers and on specialized knowledge of the content. In turn, there is a predominance of studies that address functional thinking as a content area. We conclude that more empirical studies are needed that address the mathematical knowledge that childhood and primary education teachers have of early algebra.
Cluster Synchronization in Variable-Order Fractional Community Network via Intermittent Control
Authors: Wang Yi , Wu Zhaoyan
Published: October 2021

In this paper, the cluster synchronization of a variable-order fractional community network with nonidentical dynamics is investigated. For achieving the cluster synchronization, intermittent controllers are designed, and the sufficient conditions with respect to system parameters, intermittent control instants and control gains are derived based on stability theory of fractional-order system and linear matrix inequalities (LMIs). To avoid verifying the LMIs, a corresponding simple corollary is provided. Finally, a numerical example is performed to verify the derived result.
Resolvable Networks—A Graphical Tool for Representing and Solving SAT
Authors: Kusper Gábor , Biró Csaba , Nagy Benedek
Published: October 2021

In this paper, we introduce the notion of resolvable networks. A resolvable network is a digraph of subnetworks, where subnetworks may overlap, and the inner structure of subnetworks are not interesting from the viewpoint of the network. There are two special subnetworks, Source and Sink, with the following properties: there is no incoming edge to Source, and there is no outgoing edge from Sink. Any resolvable network can be represented by a satisfiability problem in Boolean logic (shortly, SAT problem), and any SAT problem can be represented by a resolvable network. Because of that, the resolution operation is valid also for resolvable networks. We can use resolution to find out or refine the inner structure of subnetworks. We give also a pessimistic and an optimistic interpretation of subnetworks. In the pessimistic case, we assume that inside a subnetwork, all communication possibilities are represented as part of the resolvable network. In the optimistic case, we assume that each subnetwork is strongly connected. We show that any SAT problem can be visualized using the pessimistic interpretation. We show that transitivity is very limited in the pessimistic interpretation, and in this case, transitivity corresponds to resolution of clauses. In the optimistic interpretation of subnetworks, we have transitivity without any further condition, but not all SAT problems can be represented in this case; however, any such network can be represented as a SAT problem. The newly introduced graphical concept allows to use terminology and tools from directed graphs in the field of SAT and also to give graphical representations of various concepts of satisfiability problems. A resolvable network is also a suitable data structure to study, for example, wireless sensor networks. The visualization power of resolvable networks is demonstrated on some pigeon hole SAT problems. Another important application field could be modeling the communication network of an information bank. Here, a subnetwork represents a dataset of a user which is secured by a proxy. Any communication should be done through the proxy, and this constraint can be checked using our model.
Nonstandard Hulls of C*-Algebras and Their Applications
Authors: Baratella Stefano
Published: October 2021

For the sake of providing insight into the use of nonstandard techniques à la A. Robinson and into Luxemburg’s nonstandard hull construction, we first present nonstandard proofs of some known results about C*-algebras. Then we introduce extensions of the nonstandard hull construction to noncommutative probability spaces and noncommutative stochastic processes. In the framework of internal noncommutative probability spaces, we investigate properties like freeness and convergence in distribution and their preservation by the nonstandard hull construction. We obtain a nonstandard characterization of the freeness property. Eventually we provide a nonstandard characterization of the property of equivalence for a suitable class of noncommutative stochastic processes and we study the behaviour of the latter property with respect to the nonstandard hull construction.
Anatomical Model of Rat Ventricles to Study Cardiac Arrhythmias under Infarction Injury
Authors: Rokeakh Roman , Nesterova Tatiana , Ushenin Konstantin , Polyakova Ekaterina , Sonin Dmitry , Galagudza Michael , De Coster Tim , Panfilov Alexander , Solovyova Olga
Published: October 2021

Species-specific computer models of the heart are a novel powerful tool in studies of life-threatening cardiac arrhythmias. Here, we develop such a model aimed at studying infarction injury in a rat heart, the most common experimental system to investigate the effects of myocardial damage. We updated the Gattoni2016 cellular ionic model by fitting its parameters to experimental data using a population modeling approach. Using four selected cellular models, we studied 2D spiral wave dynamics and found that they include meandering and break-up. Then, using an anatomically realistic ventricular geometry and fiber orientation in the rat heart, we built a model with a post-infarction scar to study the electrophysiological effects of myocardial damage. A post-infarction scar was simulated as an inexcitable obstacle surrounded by a border zone with modified cardiomyocyte properties. For cellular models, we studied the rotation of scroll waves and found that, depending on the model, we can observe different types of dynamics: anchoring, self-termination or stable rotation of the scroll wave. The observed arrhythmia characteristics coincide with those measured in the experiment. The developed model can be used to study arrhythmia in rat hearts with myocardial damage from ischemia reperfusion and to examine the possible arrhythmogenic effects of various experimental interventions.
On Third-Order Bronze Fibonacci Numbers
Authors: Akbiyik Mücahit , Alo Jeta
Published: October 2021

In this study, we firstly obtain De Moivre-type identities for the second-order Bronze Fibonacci sequences. Next, we construct and define the third-order Bronze Fibonacci, third-order Bronze Lucas and modified third-order Bronze Fibonacci sequences. Then, we define the generalized third-order Bronze Fibonacci sequence and calculate the De Moivre-type identities for these sequences. Moreover, we find the generating functions, Binet’s formulas, Cassini’s identities and matrix representations of these sequences and examine some interesting identities related to the third-order Bronze Fibonacci sequences. Finally, we present an encryption and decryption application that uses our obtained results and we present an illustrative example.
Mixed Mesh Finite Volume Method for 1D Hyperbolic Systems with Application to Plug-Flow Heat Exchangers
Authors: Dostál Jiří , Havlena Vladimír
Published: October 2021

We present a finite volume method formulated on a mixed Eulerian-Lagrangian mesh for highly advective 1D hyperbolic systems altogether with its application to plug-flow heat exchanger modeling/simulation. Advection of sharp moving fronts is an important problem in fluid dynamics, and even a simple transport equation cannot be solved precisely by having a finite number of nodes/elements/volumes. Finite volume methods are known to introduce numerical diffusion, and there exist a wide variety of schemes to minimize its occurrence; the most recent being adaptive grid methods such as moving mesh methods or adaptive mesh refinement methods. We present a solution method for a class of hyperbolic systems with one nonzero time-dependent characteristic velocity. This property allows us to rigorously define a finite volume method on a grid that is continuously moving by the characteristic velocity (Lagrangian grid) along a static Eulerian grid. The advective flux of the flowing field is, by this approach, removed from cell-to-cell interactions, and the ability to advect sharp fronts is therefore enhanced. The price to pay is a fixed velocity-dependent time sampling and a time delay in the solution. For these reasons, the method is best suited for systems with a dominating advection component. We illustrate the method’s properties on an illustrative advection-decay equation example and a 1D plug flow heat exchanger. Such heat exchanger model can then serve as a convection-accurate dynamic model in estimation and control algorithms for which it was developed.
Compression of Neural Networks for Specialized Tasks via Value Locality
Authors: Gabbay Freddy , Shomron Gil
Published: October 2021

Convolutional Neural Networks (CNNs) are broadly used in numerous applications such as computer vision and image classification. Although CNN models deliver state-of-the-art accuracy, they require heavy computational resources that are not always affordable or available on every platform. Limited performance, system cost, and energy consumption, such as in edge devices, argue for the optimization of computations in neural networks. Toward this end, we propose herein the value-locality-based compression (VELCRO) algorithm for neural networks. VELCRO is a method to compress general-purpose neural networks that are deployed for a small subset of focused specialized tasks. Although this study focuses on CNNs, VELCRO can be used to compress any deep neural network. VELCRO relies on the property of value locality, which suggests that activation functions exhibit values in proximity through the inference process when the network is used for specialized tasks. VELCRO consists of two stages: a preprocessing stage that identifies output elements of the activation function with a high degree of value locality, and a compression stage that replaces these elements with their corresponding average arithmetic values. As a result, VELCRO not only saves the computation of the replaced activations but also avoids processing their corresponding output feature map elements. Unlike common neural network compression algorithms, which require computationally intensive training processes, VELCRO introduces significantly fewer computational requirements. An analysis of our experiments indicates that, when CNNs are used for specialized tasks, they introduce a high degree of value locality relative to the general-purpose case. In addition, the experimental results show that without any training process, VELCRO produces a compression-saving ratio in the range 13.5–30.0% with no degradation in accuracy. Finally, the experimental results indicate that, when VELCRO is used with a relatively low compression target, it significantly improves the accuracy by 2–20% for specialized CNN tasks.
Multi-Criteria Analysis for Business Location Decisions
Authors: Perez-Benitez Virginia , Gemar German , Hernández Mónica
Published: October 2021

Choosing the physical place in which to locate a company or make investments is a strategic decision that managers must make when their business activities begin and as they expand. These decisions are key to firms’ survival. This study sought to shed light on this decision problem and assist managers in making these decisions. The first research objective was to examine the different dimensions that decision makers should consider regarding locations. The second objective was to test the efficacy of multi-criteria analysis methods regarding this decision problem. More specifically, this study applied a combination of the preference ranking organization method for enrichment of evaluations and the geometric analysis for interactive aid method, complemented by the analytical hierarchy process. The last objective was to rank major European cities on their suitability as business locations. The results include a preferential ranking of 66 European cities. London is the best positioned in all dimensions, followed by Paris and Barcelona. The findings’ originality comes from the inclusion of dimensions such as climate, security, and technology, which are given little weight in other similar indices, as well as the fresh approach to this decision problem from a business perspective and the combination of methodologies.
Cancer Cell Profiling Using Image Moments and Neural Networks with Model Agnostic Explainability: A Case Study of Breast Cancer Histopathological (BreakHis) Database
Authors: Kaplun Dmitry , Krasichkov Alexander , Chetyrbok Petr , Oleinikov Nikolay , Garg Anupam , Pannu Husanbir Singh
Published: October 2021

With the evolution of modern digital pathology, examining cancer cell tissues has paved the way to quantify subtle symptoms, for example, by means of image staining procedures using Eosin and Hematoxylin. Cancer tissues in the case of breast and lung cancer are quite challenging to examine by manual expert analysis of patients suffering from cancer. Merely relying on the observable characteristics by histopathologists for cell profiling may under-constrain the scale and diagnostic quality due to tedious repetition with constant concentration. Thus, automatic analysis of cancer cells has been proposed with algorithmic and soft-computing techniques to leverage speed and reliability. The paper’s novelty lies in the utility of Zernike image moments to extract complex features from cancer cell images and using simple neural networks for classification, followed by explainability on the test results using the Local Interpretable Model-Agnostic Explanations (LIME) technique and Explainable Artificial Intelligence (XAI). The general workflow of the proposed high throughput strategy involves acquiring the BreakHis public dataset, which consists of microscopic images, followed by the application of image processing and machine learning techniques. The recommended technique has been mathematically substantiated and compared with the state-of-the-art to justify the empirical basis in the pursuit of our algorithmic discovery. The proposed system is able to classify malignant and benign cancer cell images of 40× resolution with 100% recognition rate. XAI interprets and reasons the test results obtained from the machine learning model, making it reliable and transparent for analysis and parameter tuning.
Sepsis: New Challenges and Future Perspectives for an Evolving Disease—Precision Medicine Is the Way!
Authors: Mirijello Antonio , Tosoni Alberto
Published: October 2021

Sepsis still remains the leading cause of in-hospital death in the world [...]
Exertional Desaturation Has Higher Mortality Than Non-Desaturation in COPD
Authors: Liu Shih-Feng , Chin Chien-Hung , Tseng Ching-Wang , Chen Yung-Che , Kuo Ho-Chang
Published: October 2021

Background and objectives: Exertional desaturation (ED) is often overlooked in chronic obstructive pulmonary disease (COPD). We aim to investigate the impact of ED on mortality and the predictors of ED in COPD. Materials andmethods: A cohort of COPD patients with clinically stable, widely ranging severities were enrolled. ED is defined as oxyhemoglobin saturation by pulse oximetry (SpO2) < 90% or a drop of ΔSpO2 ≥ 4% during a six-minute walk test (6MWT). Cox regression analysis is used to estimate the hazard ratio (HR) for three-year mortality. Results: A total of 113 patients were studied, including ED (N = 34) and non-ED (N = 79) groups. FVC (% of predicted value), FEV1/FVC (%), FEV1 (% of predicted value), DLCO (%), maximal inspiratory pressure, SpO2 during the 6MWT, GOLD stage, and COPD severity were significantly different between the ED and non-ED groups in univariate analysis. Low minimal SpO2 (p < 0.001) and high maximal heart rate (p = 0.04) during the 6MWT were significantly related to ED in multivariate analysis. After adjusting for age, gender, body mass index, 6MWD, FEV1, mMRC, GOLD staging, exacerbation, hs-CRP, and fibrinogen, the mortality rate of the ED group was higher than that of the non-ED group (p = 0.012; HR = 4.12; 95% CI 1.37–12.39). For deaths, the average survival time of ED was shorter than that of the non-ED group (856.4 days vs. 933.8 days, p = 0.033). Conclusions: ED has higher mortality than non-ED in COPD. COPD should be assessed for ED, especially in patients with low minimal SpO2 and high maximal HR during the 6MWT.
Coping Strategies and Health-Related Quality of Life in Pregnant Women with SARS-CoV-2 Infection
Authors: Timircan Madalina , Bratosin Felix , Vidican Iulia , Suciu Oana , Turaiche Mirela , Bota Adrian Vasile , Mitrescu Sorina , Marincu Iosif
Published: October 2021

Background and Objectives: As maternal deaths associated with the SARS-CoV-2 infection remain at several times greater than the general population, significant factors that might contribute to the higher mortality and morbidity rate are the psychological impact of the disease and pregnancy itself. Therefore, the current study’s main objective was to assess how pregnant women react and cope with the stress of COVID-19 disease and how it influences their overall health and quality of life in healthcare facilities. Materials and Methods: In this cross-sectional study, we included 304 pregnant women who successfully completed standardized forms to assess our topics of interest, comprising of the Hospital Anxiety and Depression Scale, the Short Form Health Survey-12, the Coping Orientation to Problems Experienced Inventory scale, the CORE-Outcome Measure Questionnaire, and the Quality from the Patient’s Perspective questionnaire. Results: Unemployed, pregnant women living in poverty in the rural areas had higher SARS-CoV-2 infection rates during pregnancy. They faced higher anxiety levels and depression rates, with associated increased physical burden and exhaustion. However, these findings are not influenced by hospital care since it remained unchanged among COVID-19 and non-COVID-19 maternity units, excepting significantly lower technical competence scores of COVID-19 facilities. Conclusions: As the pandemic’s consequences emerge and additional outbreaks occur, care must prioritize the additional physical burden experienced by pregnant women who have contracted COVID-19, as well as psychological, emotional, and mental health support.
Comparison of Postoperative Recovery after Manual and Target-Controlled Infusion of Remifentanil in Bariatric Surgery
Authors: Kasputytė Greta , Gecevičienė Paulina , Karbonskienė Aurika , Macas Andrius , Maleckas Almantas
Published: October 2021

Background and Objectives: Early postoperative recovery after surgery is a key point for patients’ safety and comfort. Moreover, operating room turnover depends on recovery time. Our aim was to assess which method of remifentanil administration, manual (MI) or target-controlled infusion (TCI), could reduce patient time in recovery room. In this study, patients’ recovery times were registered and compared among the groups. Materials and Methods: We enrolled 31 morbidly obese patients in this prospective study. All of them had undergone bariatric surgery at the Hospital of Lithuanian University of Health Sciences Kauno Klinikos in 2020. Sevoflurane/remifentanil anaesthesia was performed for all patients. The patients were randomly assigned to the manual infusion (MI) (control group) or target-controlled infusion (TCI) group for the method of the administration of remifentanil. While the patients were waking up after the surgery, we recorded spontaneous breathing and airway reflexes recovery time, time of extubation, eye opening, recovery of orientation and beginning of the following oral command. For the TCI group, we also documented remifentanil concentrations in the blood (automatic infusion pump). Results: Patients did not differ in demographic values and duration of remifentanil infusion. We found that remifentanil consumption in the TCI group was lower, p = 0.02. Despite lower remifentanil consumption in the TCI group patients, they demonstrated longer total recovery time than the control group patiens: 14 (12–20) vs. 10 (6–16), p = 0.001. Conclusions: The study showed that, upon comparing the TCI method with MI, manual infusion produced better results in postoperative patient recovery. Additionally, higher doses of remifentanil were consumed using MI. In conclusion, the dosage recommended by highly qualified anaesthesiologists is favourable for morbidly obesity patients when compared to the TCI method.
The Change of Lumbar Spinal Stenosis Symptoms over a Six-Year Period in Community-Dwelling People
Authors: Otani Koji , Kikuchi Shin-ichi , Yabuki Shoji , Nikaido Takuya , Watanabe Kazuyuki , Kato Kinshi , Kobayashi Hiroshi , Konno Shin-ichi
Published: October 2021

Background and Objectives: The high prevalence of lumbar spinal stenosis (LSS) and its negative impact on quality of life in the elderly is well known. However, the longitudinal time course of LSS symptoms remains unclear. The purpose of this study was to clarify the longitudinal time course and associated factors of LSS symptoms over a period of six years in a community. Materials and Methods: This study was conducted with data prospectively collected in 2004 and 2010 under a retrospective design. In 2004, 1578 subjects (age range: 40 to 79 years) were interviewed on LSS symptoms using a specially designed and validated questionnaire. In 2010, a follow-up study was performed by mail, to which 789 subjects of the 2004 study population responded. Considering that the presence of osteoarthritis (OA) of the knee or hip may influence the participants’ answers in the questionnaire, analysis was performed in all 789 subjects with and 513 subjects without either knee or hip OA. Changes in LSS symptoms between the initial and the 6-year survey were investigated. Multiple logistic regression analysis was used for detecting the risk factors for LSS symptom presence at the six-year follow-up. Results: 1. At the six-year follow-up, more than half of the subjects who showed LSS symptoms at the initial analysis became LSS-negative, and 12–15% of those who were LSS-negative became LSS-positive. 2. From the multiple logistic regression analysis, a lower Roland-Morris Disability Questionnaire (RDQ) score and a positive LSS symptom at the initial analysis were detected as predictive factors of the presence of LSS symptoms at the six-year follow-up in the total number of subjects, as well as just in those who did not have either knee or hip OA. Conclusions: More than half of the subjects who were LSS-positive at their initial assessment still experienced improvement in their symptoms even after 6 years. This means that both LSS symptoms and their time course vary from person to person. Predictive factors for the presence of LSS symptoms during the six-year follow-up period were RDQ score and positive LSS symptoms.
Hydroxylated Fatty Acids: The Role of the Sphingomyelin Synthase and the Origin of Selectivity
Authors: Sessa Lucia , Nardiello Anna Maria , Santoro Jacopo , Concilio Simona , Piotto Stefano
Published: October 2021

Sphingolipids are a class of lipids acting as key modulators of many physiological and pathophysiological processes. Hydroxylation patterns have a major influence on the biophysical properties of sphingolipids. In this work, we have studied the mechanism of action of hydroxylated lipids in sphingomyelin synthase (SMS). The structures of the two human isoforms, SMS1 and SMS2, have been generated through neural network supported homology. Furthermore, we have elucidated the reaction mechanism that allows SMS to recover the choline head from a phosphocholine (PC) and transfer it to ceramide, and we have clarified the role of the hydroxyl group in the interaction with the enzyme. Finally, the effect of partial inhibition of SMS on the levels of PC and sphingomyelin was calculated for different rate constants solving ordinary differential equation systems.
A Novel Multi-Objective Process Parameter Interval Optimization Method for Steel Production
Authors: Yan Yifan , Lv Zhimin
Published: October 2021

Customized small batch orders and sustainable development requirements pose challenges for product quality control and manufacturing process optimization for steel production. Building a multi-quality objective process parameter optimization method that converts the original single target optimization into multi-objective interval capability optimization has become a new method to ensure product quality qualification rate and reduce production costs. Aiming at the multi-quality objective control problem of plate products, we proposed a novel multi-objective process parameter interval optimization model (MPPIO) with equipment process control capability and parameter sensitive analysis. The multi-output support vector regression method was used to establish a multi-quality objective prediction model, which was settled as a verification model for the process parameter optimization results based on the particle swarm optimization algorithm (PSO). The process control capability functions of key parameters were fitted based on the real data in production. With these functions, each optimized particle of the classical PSO was converted into the particle beam of the MIPPO. The iteration process was weight controlled by calculating the Morris sensitivity between each input parameter and output index in the multi-quality objective prediction model, and finally the processing control window of each key parameter was determined according to the process parameter optimization results. The experimental results show that the MPPIO model can obtain the optimal parameter optimization results with the maximum processing capacity and meet the customized processing range requirements. The MPPIO model can reduce the difficulty of control and save production costs while ensuring the product properties is qualified.
Modelling Human Physiology on-Chip: Historical Perspectives and Future Directions
Authors: Pun Sirjana , Haney Li Cai , Barrile Riccardo
Published: October 2021

For centuries, animal experiments have contributed much to our understanding of mechanisms of human disease, but their value in predicting the effectiveness of drug treatments in the clinic has remained controversial. Animal models, including genetically modified ones and experimentally induced pathologies, often do not accurately reflect disease in humans, and therefore do not predict with sufficient certainty what will happen in humans. Organ-on-chip (OOC) technology and bioengineered tissues have emerged as promising alternatives to traditional animal testing for a wide range of applications in biological defence, drug discovery and development, and precision medicine, offering a potential alternative. Recent technological breakthroughs in stem cell and organoid biology, OOC technology, and 3D bioprinting have all contributed to a tremendous progress in our ability to design, assemble and manufacture living organ biomimetic systems that more accurately reflect the structural and functional characteristics of human tissue in vitro, and enable improved predictions of human responses to drugs and environmental stimuli. Here, we provide a historical perspective on the evolution of the field of bioengineering, focusing on the most salient milestones that enabled control of internal and external cell microenvironment. We introduce the concepts of OOCs and Microphysiological systems (MPSs), review various chip designs and microfabrication methods used to construct OOCs, focusing on blood-brain barrier as an example, and discuss existing challenges and limitations. Finally, we provide an overview on emerging strategies for 3D bioprinting of MPSs and comment on the potential role of these devices in precision medicine.
New Ultrasensitive Sandwich-Type Immunoassay of Dendritic Tri-Fan Blade-like PdAuCu Nanoparticles/Amine-Functionalized Graphene Oxide for Label-Free Detection of Carcinoembryonic Antigen
Authors: Xu Pingping , Feng Wenpo , Wang Mei , Zhang Ling , Liang Gaofeng , Jing Aihua
Published: October 2021

The early detection of tumor markers has an effective role in the treatment of cancer. Here, a new sandwich-type electrochemical immunosensor for early label-free detection of the cancer biomarker carcinoembryonic antigen (CEA) was developed. Dendritic tri-fan blade-like PdAuCu nanoparticles (PdAuCu NPs)/amine functionalized graphene oxide (NH2-GO) were the label of secondary antibodies (Ab2), and Au nanoparticle-decorated polydopamines (Au/PDA) were immobilized on a screen-printed carbon electrode (SPCE) as the substrate materials. Dendritic tri-fan blade-like PdAuCu NPs/NH2-GO was synthesized according to a simple hydrothermal procedure and used to immobilize antibodies (Ab2) with large surfaces areas, increased catalytic properties and good adsorption to amplify the current signals. Subsequently, Ab2/PdAuCu NPs/NH2-GO catalyzed the reduction of H2O2 in the sandwich-type immunoreactions. Under optimal conditions, the immunosensor exhibited a satisfactory response to CEA with a limit detection of 0.07 pg mL−1 and a linear detection range from 0.1 pg mL−1 to 200 ng mL−1. The proposed immunosensor could be suitable enough for a real sample analysis of CEA, and has clinical value in the early diagnosis of cancer.
Diversity of the Tryptophanase Gene and Its Evolutionary Implications in Living Organisms
Authors: Boya Bharath Reddy , Kumar Prasun , Lee Jin-Hyung , Lee Jintae
Published: October 2021

Tryptophanase encoded by the gene tnaA is a pyridoxal phosphate-dependent enzyme that catalyses the conversion of tryptophan to indole, which is commonly used as an intra- and interspecies signalling molecule, particularly by microbes. However, the production of indole is rare in eukaryotic organisms. A nucleotide and protein database search revealed tnaA is commonly reported in various Gram-negative bacteria, but that only a few Gram-positive bacteria and archaea possess the gene. The presence of tnaA in eukaryotes, particularly protozoans and marine organisms, demonstrates the importance of this gene in the animal kingdom. Here, we document the distribution of tnaA and its acquisition and expansion among different taxonomic groups, many of which are usually categorized as non-indole producers. This study provides an opportunity to understand the intriguing role played by tnaA, and its distribution among various types of organisms.
Occurrence of Hybrid Diarrhoeagenic Escherichia coli Associated with Multidrug Resistance in Environmental Water, Johannesburg, South Africa
Authors: Bolukaoto John Y. , Singh Atheesha , Alfinete Ntando , Barnard Tobias G.
Published: October 2021

This study was undertaken to determine the virulence and antibiotic resistance profiles of diarrhoeagenic Escherichia coli (DEC) in environmental waters of Johannesburg, South Africa. Samples were collected and cultured on selective media. An 11-plex PCR assay was used to differentiate five DEC, namely: enteroaggregative (EAEC), enterohaemorrhagic (EHEC), enteroinvasive (EIEC), enteropathogenic (EPEC) and enterotoxigenic (ETEC). The antibiotic resistance profile of isolates was determined using the VITEK®-2 automated system. The virulence profiles of 170 E. coli tested showed that 40% (68/170) were commensals and 60% (102/170) were pathogenic. EPEC had a prevalence of 19.2% (32/170), followed by ETEC 11.4% (19/170), EAEC 6% (10/170) and EHEC 3% (5/170). Hybrid DEC carrying a combination of simultaneously two and three pathogenic types was detected in twenty-eight and nine isolates, respectively. The antibiotic susceptibility testing showed isolates with multidrug resistance, including cefuroxime (100%), ceftazidime (86%), cefotaxime (81%) and cefepime (79%). This study highlighted the widespread occurrence of DEC and antibiotic resistance strains in the aquatic ecosystem of Johannesburg. The presence of hybrid pathotypes detected in this study is alarming and might lead to more severe diseases. There is a necessity to enhance surveillance in reducing the propagation of pathogenic and antibiotic-resistant strains in this area.