bluuebunny/crossref_metadata_2025 huggingface dataset:
Common ALDH3A1 Gene Variant Associated with Keratoconus Risk in the Polish Population
Authors: Berdyński Mariusz , Krawczyk Piotr , Safranow Krzysztof , Borzemska Beata , Szaflik Jacek P. , Nowakowska-Żawrocka Karolina , Żekanowski Cezary , Giebułtowicz Joanna
Published: December 2021

Background: ALDH3A1 protein is important in maintaining corneal physiology and protecting the eye from UV damage. However, none of the genome-wide association studies has indicated that the ALDH3A1 locus is associated with keratoconus. In this study, we examined the potential role of ALDH3A1 variants as risk factors for keratoconus incidence and severity in a large group of Polish keratoconus patients. Methods: In the first stage we analyzed the coding region sequence of the ALDH3A1 in a subgroup of keratoconus. Then, we genotyped three selected ALDH3A1 variants in a larger KC group of patients (n = 261) and healthy controls (n = 317). Results: We found that the rs1042183 minor allele A is a risk factor for keratoconus in the dominant model (OR = 2.06, 95%CI = 1.42–2.98, p = 0.00013). The rs2228100 variant genotypes appear to be associated with an earlier age of KC diagnosis in the Polish population (p = 0.055 for comparison of three genotypes and p = 0.022 for the dominant inheritance model). Conclusions: The rs1042183 variant in ALDH3A1 is associated with keratoconus risk in the Polish population. The differences in the allele frequency between both populations could be partially responsible for the difference in the disease prevalence.
Covert Brain Infarcts in Patients with Philadelphia Chromosome-Negative Myeloproliferative Disorders
Authors: Kuznetsova Polina I. , Raskurazhev Anton A. , Konovalov Rodion N. , Krotenkova Marina V. , Chechetkin Andrey O. , Lagoda Olga V. , Melikhyan Anait L. , Tanashyan Marine M.
Published: December 2021

Backgrounds and Purpose. Philadelphia chromosome-negative myeloproliferative disorders (Ph-negative MPD) are a rare group of hematological diseases, including three distinct pathologies: essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF). They most often manifest with thrombotic complications, including cerebrovascular events. Covert brain infarcts (CBIs) are defin ed as predominantly small ischemic cerebral lesions that are detected using magnetic resonance imaging (MRI) in the absence of clinical stroke events. The relationship between MPD and CBIs remains unclear. Methods. Included in the study were 103 patients with the diagnosis of Ph-MPD (according to WHO 2016 criteria) (median age—47 (35; 54) years; 67% female). In total, 38 patients had ET, 42 had PV, and 23 had PMF. They underwent clinical examination, routine laboratory analyses (complete blood count), brain MRI, ultrasound carotid artery, flow-mediated dilatation (as a measure of endothelial dysfunction—FMD). Results. Overall, 23 patients experienced an ischemic stroke (as per MRI and/or clinical history), of which 16 (15.5%) could be classified as CBIs. The rate of CBIs per MPD subtype was statistically non-significant between groups (p = 0.35): ET–13.2%, PV–21.4%, and PMF–8.7%. The major vascular risk factors, including arterial hypertension, carotid atherosclerosis, and prior venous thrombosis, were not associated with CBIs (p > 0.05). Age was significantly higher in patients with CBIs compared to patients without MRI ischemic lesions: 50 (43; 57) years vs. 36 (29; 48) (p = 0.002). The frequency of headaches was comparable between the two groups. CBIs were associated with endothelial dysfunction (OR - 0.71 (95% CI: 0.49–0.90; p = 0.02)) and higher hemoglobin levels (OR—1.21 (95% CI: 1.06–1.55); p =0.03). Conclusions. CBIs are common in patients with Ph-negative MPD. Arterial hypertension and carotid atherosclerosis were not associated with CBIs in this group of patients. The most significant factors in the development of CBIs were endothelial dysfunction (as measured by FMD) and high hemoglobin levels. Patients with Ph-negative MPD and CBIs were older and had more prevalent endothelial dysfunction.
Multiparametric Ultrasound Approach Using a Tree-Based Decision Classifier for Inconclusive Focal Liver Lesions Evaluated by Contrast Enhanced Ultrasound
Authors: Moga Tudor Voicu , David Ciprian , Popescu Alina , Lupusoru Raluca , Heredea Darius , Ghiuchici Ana M. , Foncea Camelia , Burdan Adrian , Sirli Roxana , Danilă Mirela , Ratiu Iulia , Bizerea-Moga Teofana , Sporea Ioan
Published: December 2021

Background: Multiparametric ultrasound (MPUS) is a concept whereby the examiner is encouraged to use the latest features of an ultrasound machine. The aim of this study was to reanalyze inconclusive focal liver lesions (FLLs) that had been analyzed via contrast enhanced ultrasound (CEUS) using the MPUS approach with the help of a tree-based decision classifier. Materials and methods: We retrospectively analyzed FLLs that were inconclusive upon CEUS examination in our department, focusing our attention on samples taken over a period of two years (2017−2018). MPUS reanalysis followed a three-step algorithm, taking into account the liver stiffness measurement (LSM), time–intensity curve analysis (TIC), and parametric imaging (PI). After processing all steps of the algorithm, a binary decision tree classifier (BDTC) was used to achieve a software-assisted decision. Results: Area was the only TIC-CEUS parameter that showed a significant difference between malign and benign lesions with a cutoff of >−19.3 dB for washout phenomena (AUROC = 0.58, Se = 74.0%, Sp = 45.7%). Using the binary decision tree classifier (BDTC) algorithm, we correctly classified 71 out of 91 lesions according to their malignant or benignant status, with an accuracy of 78.0% (sensitivity = 62%, specificity = 45%, and precision = 80%). Conclusions: By reevaluating inconclusive FLLs that had been analyzed via CEUS using MPUS, we managed to determine that 78% of the lesions were malignant and, in 28% of them, we established the lesion type.
Low-Parameter Small Convolutional Neural Network Applied to Functional Medical Imaging of Tc-99m Trodat-1 Brain Single-Photon Emission Computed Tomography for Parkinson’s Disease
Authors: Chang Yu-Chieh , Hsieh Te-Chun , Chen Jui-Cheng , Wang Kuan-Pin , Hsu Zong-Kai , Chan Pak-Ki , Kao Chia-Hung
Published: December 2021

Parkinson’s disease (PD), a progressive disease that affects movement, is related to dopaminergic neuron degeneration. Tc-99m Trodat-1 brain (TRODAT) single-photon emission computed tomography (SPECT) aids the functional imaging of dopamine transporters and is used for dopaminergic neuron enumeration. Herein, we employed a convolutional neural network to facilitate PD diagnosis through TRODAT SPECT, which is simpler than models such as VGG16 and ResNet50. We retrospectively collected the data of 3188 patients (age range 20–107 years) who underwent TRODAT SPECT between June 2011 and December 2019. We developed a set of functional imaging multiclassification deep learning algorithms suitable for TRODAT SPECT on the basis of the annotations of medical experts. We then applied our self-proposed model and compared its results with those of four other models, including deep and machine learning models. TRODAT SPECT included three images collected from each patient: one presenting the maximum absorption of the metabolic function of the striatum and two adjacent images. An expert physician determined that our model’s accuracy, precision, recall, and F1-score were 0.98, 0.98, 0.98, and 0.98, respectively. Our TRODAT SPECT model provides an objective, more standardized classification correlating to the severity of PD-related diseases, thereby facilitating clinical diagnosis and preventing observer bias.
Biological Efficacy Evaluation of a Non-Cross-Linked Hyaluronic Acid Dermal Filler for Biomedical Application in Inflammatory Scalp Conditions
Authors: Sommatis Sabrina , Capillo Maria Chiara , Liga Elsa , Maccario Cristina , Rauso Raffaele , Herrera Martha , Zerbinati Nicola , Mocchi Roberto
Published: December 2021

(1) Background: The dysbiosis of some cutaneous commensal microorganisms is the trigger factor for the activation of the inflammatory cascade by keratinocytes in many skin disorders. Mesotherapy is an innovative technique for many scalp disorders, with the function of restoring the physiology of the skin. (2) Methods: the antimicrobial, antibiofilm and anti-inflammatory activity of the non-cross-linked HA formulation (Hydro Deluxe, Matex Lab S.p.a., Brindisi, Italy) was investigated against the most common microorganisms of the scalp (Staphyloccoccus epidermis, Staphyloccoccus aureus, Cutibacterium acnes and Malassezia furfur). Anti-inflammatory activity was evaluated on an internal 3D model of Reconstructed Human Epidermis (RHE) inserts infected with the strains as pro-inflammatory stimulus. (3) Results and Conclusions: the data collected showed a good antimicrobial and antibiofilm activity against all selected strains. The HA-based formulation did not show cytotoxicity on RHE, either alone or in presence of the infectious stimulus. The analysis of the expression of Interleukin (IL)-8 levels showed an excellent ability to reduce this pro-inflammatory marker. Overall, the efficacy assessment of the formulation supported its potential effectiveness in mesotherapy for the treatment of scalp disorders.
Precise-Integration Time-Domain Formulation for Optical Periodic Media
Authors: Sirvent-Verdú Joan Josep , Francés Jorge , Márquez Andrés , Neipp Cristian , Álvarez Mariela , Puerto Daniel , Gallego Sergi , Pascual Inmaculada
Published: December 2021

A numerical formulation based on the precise-integration time-domain (PITD) method for simulating periodic media is extended for overcoming the Courant-Friedrich-Levy (CFL) limit on the time-step size in a finite-difference time-domain (FDTD) simulation. In this new method, the periodic boundary conditions are implemented, permitting the simulation of a wide range of periodic optical media, i.e., gratings, or thin-film filters. Furthermore, the complete tensorial derivation for the permittivity also allows simulating anisotropic periodic media. Numerical results demonstrate that PITD is reliable and even considering anisotropic media can be competitive compared to traditional FDTD solutions. Furthermore, the maximum allowable time-step size has been demonstrated to be much larger than that of the CFL limit of the FDTD method, being a valuable tool in cases in which the steady-state requires a large number of time-steps.
Prediction of Material Failure Time for a Bucket Wheel Excavator Boom Using Computer Simulation
Authors: Andraș Andrei , Radu Sorin Mihai , Brînaș Ildiko , Popescu Florin Dumitru , Budilică Daniela Ioana , Korozsi Eva Biro
Published: December 2021

Breakdown of stackers and excavators in opencast mines is possible because of operating, manufacturing and structural causes, and it produces high financial losses. These can be prevented by using various measures, including analyses and strength tests, with computerized modeling and simulation using FEA or other techniques being implemented in the recent years. In this paper a fatigue study is conducted on the boom of a BWE. Based on a computer model of the boom previously developed in SOLIDWORKS by our author team, first the modal analysis is conducted for three positions of the boom by studying the frequency response during the excavation process. This is followed by the time response determination corresponding to the maximum displacement frequency, in order to assess the stress during the excavation process, which causes the material fatigue in the boom structure. It was found that the maximum displacements appear when the BWE boom operates in a horizontal position. The aim was to estimate the period of time to failure in order to prevent unwanted accidents, and to develop a method that is applicable to any surface mining or industrial machine with similar structure.
Influence of Forced Carbonisation on the Binding Properties of Sludge with a High β-Belite Content
Authors: Bakhtin Aleksandr , Lyubomirskiy Nikolay , Fic Stanisław , Bakhtina Tamara
Published: December 2021

Alternative binders activated by forced carbonisation are regarded as one of the potential solutions to reducing greenhouse gas emissions, water, and energy consumption. Such binders, in particular those based on nepheline sludge (a by-product of alumina production), cured in carbon dioxide with subsequent hydration, are clinkerless building materials. The development of such binders contributes to the involvement of multi-tonnage solid industrial waste in the production cycle. This type of waste is capable of binding man-made CO2 and transforming it into stable insoluble compounds, having binder properties. The optimum technological parameters of the forced carbonisation of the nepheline slime binder was determined by the mathematical planning of the experiment. The novelty of the research is the expansion of the secondary raw material base that can bind the man-made CO2 with obtaining the construction products of appropriate quality. It was revealed that the process of active CO2 absorption by the minerals of nepheline slime is observed in the first 120 min of the forced carbonization. Immediately after carbonisation, the resulting material develops compressive strength up to 57.64 MPa, and at the subsequent hydration within 28 days this figure increases to 68.71 MPa. Calcium carbonate is the main binder that determines the high mechanical properties of the samples. During the subsequent hydration of the uncoated belite, gel-like products are formed, which additionally harden the carbonised matrix. Thus, after the forced carbonisation and the following 28 days of hardening, the material with compressive strength in the range 4.38–68.71 MPa and flexural strength of 3.1–8.9 MPa was obtained. This material was characterised by water absorption by mass in the range of 13.9–23.3% and the average density of 1640–1886 kg/m3. The softening coefficient of the material was 0.51–0.99. The results obtained enables one to consider further prospects for research in this area, in terms of the introduction of additional technological parameters to study the process of forced carbonisation of nepheline slime.
A Method and Device for Automated Grinding of Small Ceramic Elements
Authors: Kacalak Wojciech , Lipiński Dariusz , Szafraniec Filip , Bałasz Błażej
Published: December 2021

The paper describes an automated method for grinding small ceramic elements using a hyperboloid wheel. The problem of automating the process of machining elements made of nonmagnetic materials with a small area and low height has been solved. Automation of the grinding process was possible thanks to automatic clamping of workpieces in the machining zone and sequential processing by a specified number of grinding wheels. The workpieces were passed through successive machining zones. The division of the allowance of individual grinding wheels was made taking into account the characteristics of the workpieces and the requirements for the results of the machining. Obtaining a long grinding zone and the effect of automatic clamping of the workpieces was possible due to the inclination of the grinding wheel axis in relation to the plane of movement of the workpieces. Innovative aggregate grinding wheels were used for grinding. The aggregates containing diamond abrasive grains, connected with a metal bond, were embedded in the porous structure of the resin bond. The aggregates ensured high efficiency of grinding, and their developed surface contributed to good holding in the resin binder. The durability of grinding wheels was 64 h, which enables the machining of 76,000 ceramic elements.
Method for Mitigating Stray Current Corrosion in Buried Pipelines Using Calcareous Deposits
Authors: Kang Sin-Jae , Hong Min-Sung , Kim Jung-Gu
Published: December 2021

Stray current corrosion in buried pipelines can cause serious material damage in a short period of time. However, the available methods for mitigating stray current corrosion are still insufficient. In this study, as a countermeasure against stray current corrosion, calcareous depositions were applied to reduce the total amount of current flowing into pipelines and to prevent corrosion. This study examined the reduction of stray current corrosion via the formation of calcareous deposit layers, composed of Ca, Mg, and mixed Ca and Mg, at the current inflow area. To verify the deposited layers, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were performed. The electrochemical tests revealed that all three types of calcareous deposits were able to effectively act as current barriers, and that they decreased the inflow current at the cathodic site. Among the deposits, the CaCO3 layer mitigated the stray current most effectively, as it was not affected by Mg(OH)2, which interferes with the growth of CaCO3. The calcium-based layer was very thick and dense, and it effectively blocked the inflowing stray current, compared with the other layers.
Fabrication of Polycrystalline Cubic Boron Nitride/Metal Composite Particles by Surface Metallization Followed by Electroless Deposition Technique
Authors: Mohamed Daoush Walid , Saad Alkhuraiji Turki , Alshammri Abdulrahman Dohymish
Published: December 2021

Polycrystalline cBN/copper composite abrasive particles were prepared by an electroless powder coating process. Ti metallization and tin/silver metallization techniques were used to improve the coating process by depositing an autocatalytic metallic layer on the surface of the cBN particles. Metallized, as well as un-metallized, cBN particles were further coated by copper using electroless deposition. Electroless copper coating of un-metallized and metallized cBN particles by 90 wt.% of copper were achieved. The surface morphology, the composition and the crystalline phase identifications of the metallized cBN particles, as well as the 10 wt.% cBN /copper composite powders, were investigated by field emission scanning electron microscopy, an energy-dispersive spectrometer and an X-ray diffractometer. The results show that the surface of the Ti metalized and tin/Ag-metallized cBN particles were covered by the nanosized Ti or Ag layer, respectively, which enhanced the deposition of the copper during the electroless deposition bath. The results also showed that the deposited layer on the metallized cBN particles was composed mainly of metallic copper. The produced 10 wt.% cBN/copper composite particles also underwent thermo-gravimetric analysis to investigate its stability at high temperature. It was revealed that the Ti-metallized cBN/copper composite powder has higher stability at 800 °C under the environmental conditions than the tin/silver-metallized and the un-metallized cBN/copper composite particles, respectively.
Numerical Modeling and Evaluation of PEM Used for Fuel Cell Vehicles
Authors: Darvishi Yousef , Hassan-Beygi Seyed Reza , Zarafshan Payam , Hooshyari Khadijeh , Malaga-Toboła Urszula , Gancarz Marek
Published: December 2021

The present study sought to analyze a novel type of polymer membrane fuel cell to be used in vehicles. The performance of the fuel cell was evaluated by modeling the types of production–consumption heat in the anode and cathode (including half-reaction heat, activation heat, and absorption/desorption heat) and waterflood conditions. The meshing of flow channels was carried out by square cells and the governing equations were numerically discretized in the steady mode using the finite difference method followed by solving in MATLAB software. Based on the simulation results, the anodic absorption/desorption heat, anodic half-reaction heat, and cathodic activation heat are positive while the cathodic absorption/desorption heat and cathodic half-reaction heat show negative values. All heat values exhibit a decremental trend over the flow channel. Considering the effect of relative humidity, the relative humidity of the cathode showed no significant change while the anode relative humidity decreased along the flow channel. The velocity at the membrane layer was considerably lower, due to the smaller permeability coefficient of this layer compared to the gas diffusion and reactants (cathode) layers.
Influence of Flux and Related Factors on Intermetallic Layer Growth within SAC305 Solder Joints
Authors: Dušek Karel , Veselý Petr , Bušek David , Petráč Adam , Géczy Attila , Illés Balázs , Krammer Oliver
Published: December 2021

Flux contained in solder paste significantly affects the process of solder joint creation during reflow soldering, including the creation of an intermetallic layer (IML). This work investigates the dependence of intermetallic layer thickness on ROL0/ROL1 flux classification, glossy or matt solder mask, and OSP/HASL/ENIG soldering pad surface finish. Two original SAC305 solder pastes differing only in the used flux were chosen for the experiment. The influence of multiple reflows was also observed. The intermetallic layer thicknesses were obtained by the image analysis of micro-section images. The flux type proved to have a significant impact on the intermetallic layer thickness. The solder paste with ROL1 caused an increase in IML thickness by up to 40% in comparison to an identical paste with ROL0 flux. Furthermore, doubling the roughness of the solder mask has increased the resulting IML thickness by 37% at HASL surface finish and by an average of 22%.
Near-Infrared Light-Responsive Shell-Crosslinked Micelles of Poly(d,l-lactide)-b-poly((furfuryl methacrylate)-co-(N-acryloylmorpholine)) Prepared by Diels–Alder Reaction for the Triggered Release of Doxorubicin
Authors: Yadav Sonyabapu , Ramesh Kalyan , Kumar Parveen , Jo Sung-Han , Yoo Seong II , Gal Yeong-Soon , Park Sang-Hyug , Lim Kwon Taek
Published: December 2021

In the present study, we developed near-infrared (NIR)-responsive shell-crosslinked (SCL) micelles using the Diels–Alder (DA) click reaction between an amphiphilic copolymer poly(d,l-lactide)20-b-poly((furfuryl methacrylate)10-co-(N-acryloylmorpholine)78) (PLA20-b-P(FMA10-co-NAM78)) and a diselenide-containing crosslinker, bis(maleimidoethyl) 3,3′-diselanediyldipropionoate (BMEDSeDP). The PLA20-b-P(FMA10-co-NAM78) copolymer was synthesized by RAFT polymerization of FMA and NAM using a PLA20-macro-chain transfer agent (PLA20-CTA). The DA reaction between BMEDSeDP and the furfuryl moieties in the copolymeric micelles in water resulted in the formation of SCL micelles. The SCL micelles were analyzed by 1H-NMR, FE-SEM, and DLS. An anticancer drug, doxorubicin (DOX), and an NIR sensitizer, indocyanine green (ICG), were effectively incorporated into the SCL micelles during the crosslinking reaction. The DOX/ICG-loaded SCL micelles showed pH- and NIR-responsive drug release, where burst release was observed under NIR laser irradiation. The in vitro cytotoxicity analysis demonstrated that the SCL was not cytotoxic against normal HFF-1 cells, while DOX/ICG-loaded SCL micelles exhibited significant antitumor activity toward HeLa cells. Thus, the SCL micelles of PLA20-b-P(FMA10-co-NAM78) can be used as a potential delivery vehicle for the controlled drug release in cancer therapy.
Influence of Water-Induced Degradation of Polytetrafluoroethylene (PTFE)-Coated Woven Fabrics Mechanical Properties
Authors: Ambroziak Andrzej , Kłosowski Paweł
Published: December 2021

The impact of water-induced degradation on the mechanical properties of the chosen two PTFE-coated, glass threads woven fabrics is investigated in this paper. The paper begins with a survey of literature concerning the investigation and determination of coated woven fabric properties. The authors carried out the uniaxial tensile tests with an application of flat and curved grips to establish the proper values of the ultimate tensile strength and the longitudinal stiffness of groups of specimens treated with different moisture conditions. Despite the water resistance of the main materials used for fabrics manufacturing, the change of the mechanical properties caused by the influence of water immersion has been noticed. The reduction in the tensile strength resulting under waterlogged is observed in the range from 5% to 16% depending on the type of investigated coated woven fabric and direction of weft or warp.
Method of Mathematical Modeling for the Experimental Evaluation of Flame-Retardant Materials’ Parameters
Authors: Korolchenko Dmitry Alexandrovich , Eremina Tatiana Yurievna
Published: December 2021

Mathematical and experimental research plays an active role in fire protection investigation. The choice of optimal conditions for the experimental program is the main methodological part of this research. The peculiarities of new fire-protective compositions were investigated. Many experiments in this work are aimed at the investigation of the physical and chemical properties of the materials.
Experimental Investigation on Bending Behavior of Existing RC Beam Retrofitted with SMA-ECC Composites Materials
Authors: Qian Hui , Zhang Qingyuan , Zhang Xun , Deng Enfeng , Gao Jundong
Published: December 2021

In order to realize the self-centering, high energy consumption, and high ductility of the existing building structure through strengthening and retrofit of structure, a method of reinforced concrete (RC) beam strengthened by using Shape Memory Alloy (SMA) and Engineered Cementitious Composites (ECC) was proposed. Four kinds of specimens were designed, including one beam strengthened with enlarging section area of steel reinforced concrete, one beam strengthened with enlarging section area of SMA reinforced concrete, beam strengthened with enlarging section area of SMA reinforced ECC, and beam strengthened with enlarging section area of steel reinforced ECC; these specimens were manufactured for the monotonic cycle loading tests study on its bending behavior. The influence on the bearing capacity, energy dissipation performance, and self-recovery capacity for each test specimens with different strengthening materials were investigated, especially the bending behavior of the beams strengthened by SMA reinforced ECC. The results show that, compared with the ordinary reinforced concrete beams, strengthening existing RC beam with enlarging section area of SMA reinforced ECC can improve the self-recovery capacity, ductility, and deformability of the specimens. Finally, a revised design formula for the bending capacity of RC beams, strengthened with enlarging sections of ECC, was proposed by considering the tensile capacity provided by ECC, and the calculated values are in good agreement with the experimental value, indicating that the revised formula can be well applied to the beam strengthening with enlarging section of SMA-ECC Materials.
Shear Strengthening of High Strength Concrete Beams That Contain Hooked-End Steel Fiber
Authors: Yun Hyun-Do , Jeong Gwon-Young , Choi Won-Chang
Published: December 2021

Steel fiber has been used successfully in concrete mixtures to control volumetric changes, including shrinkage. However, the feasibility of the use of steel fiber has been restricted to nonstructural construction, such as ‘slab on ground’. Recently, researchers have attempted to expand the applications of steel fiber to replace structural reinforcement (rebar) and have shown promising results in its substitution for shear reinforcement. Few studies have been conducted to ensure the feasibility of using steel fiber in structural components, however. This experimental study was designed to investigate the shear performance of steel fiber-reinforced concrete beams using the tensile strength of steel fiber and the shear span-to-depth ratio as variables. The experimental results indicate that the tensile strength of steel fiber significantly affects the shear strength of steel fiber-reinforced concrete beams, regardless of the shear span-to-depth ratio, and that steel fiber can play a role in shear reinforcement of concrete beams.
Comparison of Numerical Simulation Techniques of Ballistic Ceramics under Projectile Impact Conditions
Authors: Zochowski Pawel , Bajkowski Marcin , Grygoruk Roman , Magier Mariusz , Burian Wojciech , Pyka Dariusz , Bocian Miroslaw , Jamroziak Krzysztof
Published: December 2021

This article presents an analysis of the effectiveness of available numerical techniques in mapping the characteristic behavior of ballistic ceramics under projectile impact conditions. As part of the work, the ballistic tests were performed on the layered ceramic/steel composite armor and tested with the 7.62 × 39 mm, armor-piercing incendiary (API) BZ projectile. The experimental tests were then mapped using computer simulations. In numerical analyses, four different techniques were used to describe cubic ceramic tiles Al2O3 placed on the ARMOX 500T steel backing plate, i.e.,: the Finite Element Method without Erosion (FEM), Finite Element with erosion (FEM + Erosion), Smoothed Particles Hydrodynamics (SPH) and a hybrid method that converts finite elements to SPH particles after exceeding the defined failure criteria (FEM to SPH conversion). The effectiveness of the individual methods was compared in terms of quality (mapping of characteristic phenomena occurring during the penetration process), quantity (bulge height of the backing plate) and time needed to complete the calculations. On the basis of the results of the experiments and numerical simulations, it was noticed that the most accurate reproduction of the phenomenon of ballistic impact of AP projectiles on ceramic/steel composite armor can be obtained by using a hybrid method, incorporating the conversion of finite elements into SPH particles. This method should be used in cases where accuracy of the results is more important than the time required to complete the calculations. In other situations where the purpose of the calculation is not to determine, for example, the exact value of penetration depth but only to observe a certain trend, the FEM method with defined erosion criteria (variant 2), which is more than 10 times faster, can be successfully used.
Experimental Evaluation and Modeling of Physical Hardening in Asphalt Binders
Authors: Tozzi Chiara , Dalmazzo Davide , Baglieri Orazio , Santagata Ezio
Published: December 2021

The research described in this paper deals with the experimental evaluation and modeling of physical hardening in asphalt binders. The term physical hardening refers to a reversible phenomenon occurring at low temperatures that causes time-dependent changes in viscoelastic properties. The experimental approach, followed to quantitatively assess physical hardening, was based on flexural creep tests carried out by means of the Bending Beam Rheometer at various temperatures and conditioning times. The results obtained confirmed that hardening phenomena have a significant influence on the creep response of asphalt binders, to an extent that can be quantitatively assessed by referring to the appropriate rheological parameters and by applying the loading time–conditioning time superposition principle. The experimental data were fitted to a mechanical model proposed in the literature (composed of a single Kelvin–Voigt element) and thereafter to an improved model (with two Kelvin–Voigt elements in series). Both models were assessed in terms of their prediction accuracy. The improved model was found to better describe physical hardening effects in the case of both short- and long-term conditioning. Practical implications of the study were finally highlighted by referring to possible ranking criteria to be introduced in acceptance procedures for the comparative evaluation of asphalt binders.
Rheological Behaviour of Cementitious Materials Incorporating Solid–Solid Phase Change Materials
Authors: Plancher Lionel , Pierre Alexandre , Nguyen Giao T. M. , Hébert Ronan L. , Ledésert Béatrice A. , Di Martino Patrick , Mélinge Yannick
Published: December 2021

Nowadays, thermal regulation of the indoor environment is mandatory to reduce greenhouse gas emissions. The incorporation of Phase Change Materials (PCMs) and especially solid–solid PCMs (s/s PCMs) into building materials can be a major step forward in reducing energy consumption. Such materials are used for their high latent heat to save and release heat during phase change. To integrate these products in the fabrication of cementitious materials, it is essential to predict their influence on the rheological behaviour of construction materials. In this work, rheological measurements were carried out on composite suspensions made of cement or mortar plus s/s PCMs. Results showed that the fitting of the Herschel–Bulkley model with a constant value of flow exponent was reliable. The s/s PCMs influenced the consistency and the yield strength values, with the yield strength value being only slightly affected. The adaptation of an existing viscosity model is proposed to predict the consistency value of suspensions. Finally, an innovative approach to predict the flow behaviour is proposed and we highlight the research needs to mainstream the use of s/s PCMs in construction materials.
Inverse Determination of Johnson–Cook Parameters of Additively Produced Anisotropic Maraging Steel
Authors: Eisseler Rocco , Gutsche Daniel , Maucher Clemens , Möhring Hans-Christian
Published: December 2021

In powder bed-based additive manufacturing (AM), complex geometries can be produced in a layer-wise approach. Results of material science experiments regarding material property identification, e.g., tensile strength, show interdependencies between the test load direction and the layer orientation. This goes hand-in-hand with the measured cutting force, changing with the relative angle between cutting direction and layer orientation in orthogonal cutting tests. However, due to the specific process characteristics, the layer orientation results in anisotropic material properties. Therefore, during machining, the material behaves depending on the buildup direction, which influences the cutting process. To predict this behavior, a simplified inverse approach is developed to determine the buildup direction-dependent parameters of a modified Johnson–Cook model for cutting simulation. To qualify these cutting models, mainly the cutting force and additionally the chip formation examined during orthogonal cuts are used. In the present paper, the influence of the laser-powder-bed-fusion (LPBF) process parameters on subtractive post-processing are shown. A good agreement between verification experiments and simulations is achieved.
Formation and Evolution of sp2 Hybrid Conjugate Structure of Polyacrylonitrile Precursor during Stabilization
Authors: Dong Ruihao , Wu Jianglu , You Ting , Cao Weiyu
Published: December 2021

The generated sp2 hybrid conjugate structure of a C atom, which resulted from the chemical reaction affected by temperature and time, is an effective six-membered ring planar structure of the final carbon fiber. This kind of hybrid conjugate structure determined the formation of the final structure and mechanical properties of carbon fiber. In this paper, the formation and evolution of sp2 hybrid conjugated structures of PAN precursor during thermal stabilization were investigated by Raman, UV-vis and 13C-NMR methods. The results indicated that with the increase of stabilization temperature, the degree of the sp2 hybrid conjugated structure of stabilized PAN fiber increases “linearly”, while the content of the sp2 hybrid carbon atoms increases with “S-type”. The final sp2 hybrid conjugated ring structure is mainly composed of single-ring, double-ring, triple-ring, and double-bond structures. Compared with the time factor, the temperature effect plays a decisive role in the formation of the sp2 hybrid conjugate structure.
Spatiotemporal Dynamics in a Predator–Prey Model with Functional Response Increasing in Both Predator and Prey Densities
Authors: Yang Ruizhi , Song Qiannan , An Yong
Published: December 2021

In this paper, a diffusive predator–prey system with a functional response that increases in both predator and prey densities is considered. By analyzing the characteristic roots of the partial differential equation system, the Turing instability and Hopf bifurcation are studied. In order to consider the dynamics of the model where the Turing bifurcation curve and the Hopf bifurcation curve intersect, we chose the diffusion coefficients d1 and β as bifurcating parameters. In particular, the normal form of Turing–Hopf bifurcation was calculated so that we could obtain the phase diagram. For parameters in each region of the phase diagram, there are different types of solutions, and their dynamic properties are extremely rich. In this study, we have used some numerical simulations in order to confirm these ideas.
New Modified Burr III Distribution, Properties and Applications
Authors: Jamal Farrukh , Abuzaid Ali , Tahir Muhammad , Nasir Muhammad , Khan Sadaf , Mashwani Wali
Published: December 2021

In this article, Burr III distribution is proposed with a significantly improved functional form. This new modification has enhanced the flexibility of the classical distribution with the ability to model all shapes of hazard rate function including increasing, decreasing, bathtub, upside-down bathtub, and nearly constant. Some of its elementary properties, such as rth moments, sth incomplete moments, moment generating function, skewness, kurtosis, mode, ith order statistics, and stochastic ordering, are presented in a clear and concise manner. The well-established technique of maximum likelihood is employed to estimate model parameters. Middle-censoring is considered as a modern general scheme of censoring. The efficacy of the proposed model is asserted through three applications consisting of complete and censored samples.
Survival Rates of Dental Implants in Autogenous and Allogeneic Bone Blocks: A Systematic Review
Authors: Donkiewicz Phil , Benz Korbinian , Kloss-Brandstätter Anita , Jackowski Jochen
Published: December 2021

Background and Objectives: Preliminary studies emphasize the similar performance of autogenous bone blocks (AUBBs) and allogeneic bone blocks (ALBBs) in pre-implant surgery; however, most of these studies include limited subjects or hold a low level of evidence. The purpose of this review is to test the hypothesis of indifferent implant survival rates (ISRs) in AUBB and ALBB and determine the impact of various material-, surgery- and patient-related confounders and predictors. Materials and Methods: The national library of medicine (MEDLINE), Excerpta Medica database (EMBASE) and Cochrane Central Register of Controlled Trials (CENTRAL) were screened for studies reporting the ISRs of implants placed in AUBB and ALBB with ≥10 participants followed for ≥12 months from January 1995 to November 2021. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed via several scoring tools, dependent on the study design. Means of sub-entities were presented as violin plots. Results: An electronic data search resulted in the identification of 9233 articles, of which 100 were included in the quantitative analysis. No significant difference (p = 0.54) was found between the ISR of AUBB (96.23 ± 5.27%; range: 75% to 100%; 2195 subjects, 6861 implants) and that of ALBB (97.66 ± 2.68%; range: 90.1% to 100%; 1202 subjects, 3434 implants). The ISR in AUBB was increased in blocks from intraoral as compared to extraoral donor sites (p = 0.0003), partially edentulous as compared to totally edentulous (p = 0.0002), as well as in patients younger than 45 as compared to those older (p = 0.044), cortical as compared to cortico-cancellous blocks (p = 0.005) and in delayed implantations within three months as compared to immediate implantations (p = 0.018). The ISR of ALBB was significantly increased in processed as compared to fresh-frozen ALBB (p = 0.004), but also in horizontal as compared to vertical augmentations (p = 0.009). Conclusions: The present findings widely emphasize the feasibility of achieving similar ISRs with AUBB and ALBB applied for pre-implant bone grafting. ISRs were negatively affected in sub-entities linked to more extensive augmentation procedures such as bone donor site and dentition status. The inclusion and pooling of literature with a low level of evidence, the absence of randomized controlled clinical trials (RCTs) comparing AUBB and ALBB and the limited count of comparative studies with short follow-ups increases the risk of bias and complicates data interpretation. Consequently, further long-term comparative studies are needed.
Mediterranean Diet a Potential Strategy against SARS-CoV-2 Infection: A Narrative Review
Authors: Ferro Yvelise , Pujia Roberta , Maurotti Samantha , Boragina Giada , Mirarchi Angela , Gnagnarella Patrizia , Mazza Elisa
Published: December 2021

Mediterranean Diet represents the traditional eating habits of populations living around the Mediterranean Sea, and it is associated with a lower risk of overall mortality and cancer incidence and cardiovascular diseases. Severe acute respiratory syndrome coronavirus 2 is a new pandemic, and represents a significant and critical threat to global human health. In this study, we aimed to review the possible effects of Mediterranean Diet against the risk of the coronavirus disease 2019. Several vitamins, minerals, fatty acids, and phytochemicals with their potential anti-COVID-19 activity are presented. Different risk factors may increase or reduce the probability of contracting the disease. Mediterranean Diet has also a positive action on inflammation and immune system and could have a protective effect against severe acute respiratory syndrome coronavirus 2. Further studies are needed to corroborate the benefits of the Mediterranean Diet protective role on infection with SARS-CoV-2.
Poly(ethylene glycol) Diacrylate Iongel Membranes Reinforced with Nanoclays for CO2 Separation
Authors: Nabais Ana R. , Francisco Rute O. , Alves Vítor D. , Neves Luísa A. , Tomé Liliana C.
Published: December 2021

Despite the fact that iongels are very attractive materials for gas separation membranes, they often show mechanical stability issues mainly due to the high ionic liquid (IL) content (≥60 wt%) needed to achieve high gas separation performances. This work investigates a strategy to improve the mechanical properties of iongel membranes, which consists in the incorporation of montmorillonite (MMT) nanoclay, from 0.2 to 7.5 wt%, into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) network containing 60 wt% of the IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][TFSI]). The iongels were prepared by a simple one-pot method using ultraviolet (UV) initiated polymerization of poly(ethylene glycol) diacrylate (PEGDA) and characterized by several techniques to assess their physico-chemical properties. The thermal stability of the iongels was influenced by the addition of higher MMT contents (>5 wt%). It was possible to improve both puncture strength and elongation at break with MMT contents up to 1 wt%. Furthermore, the highest ideal gas selectivities were achieved for iongels containing 0.5 wt% MMT, while the highest CO2 permeability was observed at 7.5 wt% MMT content, due to an increase in diffusivity. Remarkably, this strategy allowed for the preparation and gas permeation of self-standing iongel containing 80 wt% IL, which had not been possible up until now.
Effect of the Thermo-Mechanical Processing on the Impact Toughness of a 12% Cr Martensitic Steel with Co, Cu, W, Mo and Ta Doping
Authors: Fedoseeva Alexandra , Nikitin Ivan , Dudova Nadezhda , Hald John , Kaibyshev Rustam
Published: December 2021

This paper presents the results of an experimental investigation of a 12% Cr steel where a significant increase in Charpy impact toughness and a slight decrease in ductile-brittle transition temperature (DBTT) from 70 °C to 65 °C were obtained through thermo-mechanical processing, including interim hot forging at 1050 °C with long-term annealing at 1000 °C, as compared with conventional heat treatment. At lower temperatures ranging from −20 °C to 25 °C, the value of impact toughness comprised ~40 J cm−2 in the present 12% Cr steel subjected to thermo-mechanical processing. The amount of δ-ferrite decreased to 3.8%, whereas the size of prior austenite grains did not change and comprised about 40–50 μm. The boundaries between δ-ferrite and martensitic laths were decorated by continuous chains of Cr- and W-rich carbides. M23C6 carbides also precipitated along the boundaries of prior austenite grains, packets, blocks and martensitic laths. Thermo-mechanical processing increased the mean size of M23C6 carbides and decreased their number particle densities along the lath boundaries. Moreover, the precipitation of a high number of non-equilibrium V-rich MX particles was induced by hot forging and long-term normalizing at 1000 °C for 24 h.
Metabolomics Defines Complex Patterns of Dyslipidaemia in Juvenile-SLE Patients Associated with Inflammation and Potential Cardiovascular Disease Risk
Authors: Robinson George A. , Peng Junjie , Pineda-Torra Ines , Ciurtin Coziana , Jury Elizabeth C.
Published: December 2021

Cardiovascular disease (CVD) is a leading cause of mortality in patients with juvenile-onset systemic lupus erythematosus (JSLE) associated with atherosclerosis. The interplay between dyslipidaemia and inflammation—mechanisms that drive atherosclerosis—were investigated retrospectively in adolescent JSLE patients using lipoprotein-based serum metabolomics in patients with active and inactive disease, compared to healthy controls (HCs). Data was analysed using machine learning, logistic regression, and linear regression. Dyslipidaemia in JSLE patients was characterised by lower levels of small atheroprotective high-density lipoprotein subsets compared to HCs. These changes were exacerbated by active disease and additionally associated with significantly higher atherogenic very-low-density lipoproteins (VLDL) compared to patients with low disease activity. Atherogenic lipoprotein subset expression correlated positively with clinical and serological markers of JSLE disease activity/inflammation and was associated with disturbed liver function, and elevated expression of T-cell and B-cell lipid rafts (cell signalling platforms mediating immune cell activation). Finally, exposing VLDL/LDL from patients with active disease to HC lymphocytes induced a significant increase in lymphocyte lipid raft activation compared to VLDL/LDL from inactive patients. Thus, metabolomic analysis identified complex patterns of atherogenic dyslipidaemia in JSLE patients associated with inflammation. This could inform lipid-targeted therapies in JSLE to improve cardiovascular outcomes.
Python-Based Open-Source Electro-Mechanical Co-Optimization System for MEMS Inertial Sensors
Authors: Amendoeira Esteves Rui , Wang Chen , Kraft Michael
Published: December 2021

The surge in fabrication techniques for micro- and nanodevices gave room to rapid growth in these technologies and a never-ending range of possible applications emerged. These new products significantly improve human life, however, the evolution in the design, simulation and optimization process of said products did not observe a similarly rapid growth. It became thus clear that the performance of micro- and nanodevices would benefit from significant improvements in this area. This work presents a novel methodology for electro-mechanical co-optimization of micro-electromechanical systems (MEMS) inertial sensors. The developed software tool comprises geometry design, finite element method (FEM) analysis, damping calculation, electronic domain simulation, and a genetic algorithm (GA) optimization process. It allows for a facilitated system-level MEMS design flow, in which electrical and mechanical domains communicate with each other to achieve an optimized system performance. To demonstrate the efficacy of the methodology, an open-loop capacitive MEMS accelerometer and an open-loop Coriolis vibratory MEMS gyroscope were simulated and optimized—these devices saw a sensitivity improvement of 193.77% and 420.9%, respectively, in comparison to their original state.