bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycling of Aluminum-Based Composites Reinforced with Boron-Tungsten Fibres
Authors: Mironovs Viktors , Usherenko Yulia , Boiko Irina , Kuzmina Jekaterina
Published: April 2022

High strength fibres of carbon, boron, silicon carbide, tungsten, and other materials are widely used to reinforce metal matrix composite materials. Carbon and boron fibers are usually used to reinforce light alloys based on aluminum and magnesium. Products made from these materials are characterized by high strength and rigidity and can be used for a long time. Technological waste containing such fibres are hazardous to the environment because they are durable and have needle-like and other sharp shapes. Therefore, they must be disposed of with extreme care. A significant incentive for the processing and reuse of waste composites of this type is the relatively high cost of production of the primary fibre and the material as a whole. With the increase in the production of such materials in recent years, the need to recycle composite waste is becoming increasingly important. Three main options for primary processing are used to prepare composites for their subsequent use. They are mechanical, thermal, and chemical grinding technologies. One of the actual and practical areas of processing technology is the method of powder metallurgy. This paper presents the main stages of processing composite materials based on an aluminium matrix and B-W fibres to obtain powder compositions. The results of the studies showing the possibility of the effective use of the obtained crushed waste to manufacture concrete products and the production of cutting and grinding tools are presented.
Design of a Real-Time Corrosion Detection and Quantification Protocol for Automobiles
Authors: Dhonde Kunj , Mirhassani Mitra , Tam Edwin , Sawyer-Beaulieu Susan
Published: April 2022

Corrosion can compromise the integrity of the vehicle. Instead, “rust proofing” a vehicle can prolong its usable life span, reducing material waste overall and permitting greater salvageability at the end of the vehicle’s life. For rust proofing, a definitive and consistent approach for detecting corrosion could be beneficial. Instead, most vehicle corrosion detection and assessment is performed visually and in an ad hoc manner without following any particular guidelines. The visual examination of corrosion depends highly on the method of analyzing and interpreting the corrosion, as well as operator’s experience in assessing and applying rust proofing. As a result, any visual assessment strategy needs standardization to minimize human error. An automated method is proposed to identify and analyze surface rust and appraise its severity for vehicles. The method demonstrated is 96% effective, low-cost, and has low computational complexity. Subsequently, the method has the potential to be conveyed to different advanced devices, such as smartphones, to measure corrosion, decreasing errors and improving measurement accuracy. Low implementation cost, and high reliability of the method contributes to its ease of use in the field, and hence, advances its accessibility to automotive professionals to identify and monitor corrosion levels, without the interference of human errors.
Prediction of Fracture Behavior of 6061 Aluminum Alloy Based on GTN Model
Authors: Ding Fengjuan , Hong Tengjiao , Xu Youlin , Jia Xiangdong
Published: April 2022

To determine the Gurson-Tvergaard-Needleman (GTN)damage model parameters of 6061 aluminum alloy after secondary heat treatment, the uniaxial tensile test was carried out on the aluminum alloy circular arc specimen, and the mechanical properties parameters and the load-displacement curve of aluminum alloy tube were obtained. With the help of the finite element reverse method, scanning electron microscope and a orthogonal test method, the GTN damage model parameters (f0, fN, fC, and fF) were calibrated, and their values were 0.004535, 0.04, 0.1, and 0.2135, respectively. Then the shear specimen and notch specimen were designed to verify the damage model, the results show that the obtained GTN damage model parameters can effectively predict the fracture failure of 6061 aluminum alloy after secondary heat treatment during the tensile process.
Shape Memory Alloy—Polymer Composites: Static and Fatigue Pullout Strength under Thermo-Mechanical Loading
Authors: Rodinò Stefano , Curcio Elio M. , Renzo Danilo A. , Sgambitterra Emanuele , Magarò Pietro , Furgiuele Franco , Brandizzi Marco , Maletta Carmine
Published: April 2022

This work was carried out within the context of an R&D project on morphable polymer matrix composites (PMC), actuated by shape memory alloys (SMA), to be used for active aerodynamic systems in automotives. Critical issues for SMA–polymer integration are analyzed that are mostly related to the limited strength of metal–polymer interfaces. To this aim, materials with suitable thermo-mechanical properties were first selected to avoid premature activation of SMA elements during polymer setting as well as to avoid polymer damage during thermal activation of SMAs. Nonstandard samples were manufactured for both static and fatigue pullout tests under thermo-mechanical loading, which are made of SMA wires embedded in cylindrical resin blocks. Fully coupled thermo-mechanical simulations, including a special constitutive model for SMAs, were also carried out to analyze the stress and temperature distribution in the SMA–polymer samples as obtained from the application of both mechanical loads and thermal activation of the SMA wires. The results highlighted the severe effects of SMA thermal activation on adhesion strength due to the large recovery forces and to the temperature increase at the metal–polymer interface. Samples exhibit a nominal pullout stress of around 940 MPa under static mechanical load, and a marked reduction to 280 MPa was captured under simultaneous application of thermal and mechanical loads. Furthermore, fatigue run-out of 5000 cycles was achieved, under the combination of thermal activation and mechanical loads, at a nominal stress of around 200 MPa. These results represent the main design limitations of SMA/PMC systems in terms of maximum allowable stresses during both static and cyclic actuation.
Tyrosinase-Based Biosensor—A New Tool for Chlorogenic Acid Detection in Nutraceutical Formulations
Authors: Munteanu Irina Georgiana , Apetrei Constantin
Published: April 2022

The purpose of our research was to develop a new enzymatic biosensor, GPH-MnPc-Tyr/SPE, using as a support screen-printed carbon electrode (SPE) modified with graphene, manganese phthalocyanine, and tyrosinase, with the aim of developing sensitive detection of chlorogenic acid (CGA). To immobilise tyrosinase on the sensor surface, crosslinking with the glutaraldehyde technique was used, thus increasing the enzyme bioactivity on this electrode. The modified electrode has a great catalytic effect on the electrochemical redox of chlorogenic acid, compared to the simple, unmodified SPE. The peak current response of the biosensor for CGA was linear in the range of 0.1–10.48 μM, obtaining a calibration curve using cyclic voltammetry (CV) and square-wave voltammetry (SWV). Subsequently, the detection limit (LOD) and the quantification limit (LOQ) were determined, obtaining low values, i.e., LOD = 1.40 × 10−6 M; LOQ = 4.69 × 10−6 M by cyclic voltammetry and LOD = 2.32 × 10−7 M; LOQ = 7.74 × 10−7 M, by square-wave voltammetry (SWV). These results demonstrate that the method is suitable for the detection of CGA in nutraceutical formulations. Therefore, GPH-MnPc-Tyr/SPE was used for the quantitative determination of CGA in three products, by means of cyclic voltammetry. The Folin–Ciocalteu spectrophotometric assay was used for the validation of the results, obtaining a good correlation between the voltammetric method and the spectrophotometric one, at a confidence level of 95%. Moreover, by means of the DPPH method, the antioxidant activity of the compound was determined, thus demonstrating the antioxidant effect of CGA in all nutraceuticals studied.
Aggregate Geometrical Features and Their Influence on the Surface Properties of Asphalt Pavement
Authors: Sun Pei , Zhang Ke , Han Sen , Xiao Yun
Published: April 2022

Aggregate geometrical features directly affect asphalt pavement surface properties, which further affect the resistance to skidding of a road surface. In order to establish a relationship between the aggregate geometrical features and pavement surface properties, this paper employs an aggregate geometric characteristic evaluation system (AGCES) to describe the form property, angularity, and surface texture of aggregate particles. The geometrical feature parameters of 15 different aggregates were examined by AGCES and the corresponding surface properties of asphalt pavement prepared from the mentioned aggregates were evaluated by sand patch method, 2-Dimension Image-based Texture Analysis Method (2D-ITAM) and Walking Friction Tester (WFT), respectively. The relationships between the pavement surface property parameters and the aggregate geometric characteristic parameters studied were developed by the Levenberg-Marquarat and universal global optimization (LM-UGO). The results show that the calculated geometric characteristic parameters are in agreement with traditional manual measurement results. The pavement surface properties are significantly influenced by aggregate angularity and aggregate surface texture. Regression relationships were established to predict pavement surface properties from the aggregate geometrical features.
Static and Fatigue Behaviour of Double-Lap Adhesive Joints and Notched Metal Samples Reinforced by Composite Overlays
Authors: Romanowicz Paweł J. , Szybiński Bogdan , Wygoda Mateusz
Published: April 2022

The use of composite overlays to increase the fatigue life of notched steel samples is discussed in this paper. For such purposes, in the first set of studies, static and fatigue tests as well as the detailed analytical and numerical analyses for samples with double-lap joints were performed. Based on such studies, the shapes of the composite overlays were set. For a better understanding of the failure forms of the investigated adhesive joints, the experimental studies were monitored with the use of digital image correlation. In the second set of experimental studies, the static and fatigue tensile tests were performed for steel samples with a rectangular opening with rounded corners reinforced by composite overlays. The different shapes (square 45 × 45 mm and long stripes 180 × 15 mm) and composite materials (GFRP and CFRP) were used as overlays. The obtained improvement of fatigue life was in the range of 180–270% in the case of the rectangular overlays and 710% in the case of application of the overlays in the form of the long stripes. This was also confirmed by numerical analyses in which a reduction in the stress concentration factor from 2.508 (bare sample) through 2.014–2.183 (square 45 × 45 mm overlays) to 1.366 (overlays in the form of long stripes 180 × 15 mm) was observed.
Effect of Lanthanum Oxide Addition on Microstructure and Wear Performance of Iron-Chromium Alloy Manufactured by Laser Direct Deposition Additive Manufacturing
Authors: Zhao Yanhua , Meng Wei , Wang Peifu , Du Chuanbin , Wang Xiaowei
Published: April 2022

Additive Manufacturing (AM) has become increasingly common, and its use in various industries is increasing. However, the microstructure, friction and wear performance of metals made by AM, such as the inexpensive and relatively good-performing iron-chromium alloys, require further investigation. Generally, adding rare earth elements can effectively improve the performance of AM alloys, such as tensile strength, wear resistance, corrosion resistance, creep resistance, etc. This work aims to study the variation of microstructure, friction and wear properties of laser additive manufacturing processed iron-chromium alloys after adding different mass fractions of La2O3. The observations obtained by scanning electron microscopy showed that, with the addition of La2O3, the microstructure of AM alloy becomes more uniform and the grains are significantly refined. It is found by friction test that the running-in period is significantly shortened after the addition of La2O3. The coefficient of friction is reduced to a minimum of 0.68. Compared with AM alloys without La2O3, the wear rate of AM alloys with La2O3 is significantly reduced, with a maximum reduction of 38%. Using an optical microscope to observe the surface morphology of the wear scar, it is found that, after adding rare earth oxide, the wear mechanisms changed from adhesive wear and abrasive wear to abrasive wear, with the spalling of hard particles at the same time.
Failure Analysis of a Cylindrical Roller Bearing Caused by Excessive Tightening Axial Force
Authors: Hou Xueqin , Diao Qing , Liu Yujian , Liu Changkui , Zhang Zheng , Tao Chunhu
Published: April 2022

The premature failure of a cylindrical roller bearing took place during service, with a total operation time of 100 h. The failure cause was analyzed by macroscopic and microscopic observation, metallographic analysis, hardness testing, tightening axial force influence analysis, and test verification. The results show that failure modes of the bearing are contact fatigue spalling, wear, and fatigue fracture. The outer ring, inner ring, rollers, and cages all have suffered relatively heavy damage in the sides corresponding to the bearing side with laser marking. Excessive load, induced by the excessive tightening axial force, derived from the lock nut, is the cause of the bearing failure. The failure mechanism is that excessive tightening axial force caused a great deformation and cylindricity increase of the inner ring raceway, which induced high local contact stress between one side of the ring raceways, as well as the corresponding ends of the rollers, resulting in the bearing failure. At last, measures for prevention of this failure are put forward as follows: controlling the tightening axial force within the range of technical requirement, increasing the convexity of the inner ring raceway and rollers, and decreasing the grinding undercut size of the inner ring.
A Conflict Solving Process Based on Mapping between Physical Parameters and Engineering Parameters
Authors: Zhang Peng , Ma Qianhao , Nie Zifeng , Li Xindi
Published: April 2022

With the continuous expansion of system scale, the parameter coupling of the system is prominent. Due to limitations in knowledge and experience, it is difficult for designers to objectively analyze the interaction relationship between parameters, resulting in the low accuracy of engineering parameter selection, hence affecting conflict solving. In order to improve the accuracy of engineering parameter selection and the efficiency of conflict solving, this paper proposes a conflict solving process based on mapping between physical parameters and engineering parameters. First, the physical parameters related to the components of the system function model are extracted, and dimensional analysis is used to construct a physical parameter logical network. Secondly, the physical parameter change path related to the problem in the physical parameter logical network is found, and the physical parameter sets corresponding to both conflicting parties are obtained. Then, the engineering parameters corresponding to conflicts can be selected through the mapping model between physical parameters and engineering parameters, which is trained by a neural network with the sample data of physical parameter sets and engineering parameters in existing cases. Finally, Theory of Inventive Problem Solving (TRIZ) tools are used to solve conflicts, and the final design scheme is obtained through evaluation. The feasibility and effectiveness of the proposed method are verified by redesigning a bulk traditional Chinese medicine dispenser.
Dual-Modal Hybrid Control for an Upper-Limb Rehabilitation Robot
Authors: Feng Guang , Zhang Jiaji , Zuo Guokun , Li Maoqin , Jiang Dexin , Yang Lei
Published: April 2022

The recovery treatment of motor dysfunction plays a crucial role in rehabilitation therapy. Rehabilitation robots are partially or fully replacing therapists in assisting patients in exercise by advantage of robot technologies. However, the rehabilitation training system is not yet intelligent enough to provide suitable exercise modes based on the exercise intentions of patients with different motor abilities. In this paper, a dual-modal hybrid self-switching control strategy (DHSS) is proposed to automatically determine the exercise mode of patients, i.e., passive and assistive exercise mode. In this strategy, the potential field method and the ADRC position control are employed to plan trajectories and assist patients’ training. Dual-modal self-switching rules based on the motor and impulse information of patients are presented to identify patients’ motor abilities. Finally, the DHSS assisted five subjects in performing the training with an average deviation error of less than 2 mm in both exercise modes. The experimental results demonstrate that the muscle activation of the subjects differed significantly in different modes. It also verifies that DHSS is reasonable and effective, which helps patients to train independently without therapists.
New Design of Hy-Vo Chain Based on the Ultra-Small Rolling Radius
Authors: An Lichi , Cheng Yabing , Li Jiabao , Xu Weilong
Published: April 2022

To improve the system meshing performance and the chain stability, a totally new type Hy-Vo chain with an ultra-small rolling radius is proposed in this research. According to the rolling theory of the rocker pin, the design method and the meshing system for the new Hy-Vo chain are proposed. Based on the analysis model of polygonal action, by calculating a specific example, it is proved that the variable pitch characteristic of the new Hy-Vo chain is controllable. Through comparing the system center distance fluctuations for the new and the classical Hy-Vo chain, it is shown that both the system fluctuation difference and the system running deviation are all smaller for the new Hy-Vo chain. Combined with the analysis of Multi Flexible Body Dynamics (MFBD), for the new Hy-Vo chain plate and the rocker pin, the stress distribution is more uniform, and the chain life is longer. As a result, the new Hy-Vo chain with the ultra-small rolling radius has a better meshing performance and fatigue resistance, as well as better process economy. Moreover, the new design proposed in this paper is not only a novel structure for the Hy-Vo chain drive, but it also reveals the meshing mechanism and the controllable variable pitch characteristic.
Research of U-Net-Based CNN Architectures for Metal Surface Defect Detection
Authors: Konovalenko Ihor , Maruschak Pavlo , Brezinová Janette , Prentkovskis Olegas , Brezina Jakub
Published: April 2022

The quality, wear and safety of metal structures can be controlled effectively, provided that surface defects, which occur on metal structures, are detected at the right time. Over the past 10 years, researchers have proposed a number of neural network architectures that have shown high efficiency in various areas, including image classification, segmentation and recognition. However, choosing the best architecture for this particular task is often problematic. In order to compare various techniques for detecting defects such as “scratch abrasion”, we created and investigated U-Net-like architectures with encoders such as ResNet, SEResNet, SEResNeXt, DenseNet, InceptionV3, Inception-ResNetV2, MobileNet and EfficientNet. The relationship between training validation metrics and final segmentation test metrics was investigated. The correlation between the loss function, the DSC, IoU, Recall, Precision and F1 validation metrics and DSC test metrics was calculated. Recognition accuracy was analyzed as affected by the optimizer during neural network training. In the context of this problem, neural networks trained using the stochastic gradient descent optimizer with Nesterov momentum were found to have the best generalizing properties. To select the best model during its training on the basis of the validation metrics, the main test metrics of recognition quality (Dice similarity coefficient) were analyzed depending on the validation metrics. The ResNet and DenseNet models were found to achieve the best generalizing properties for our task. The highest recognition accuracy was attained using the U-Net model with a ResNet152 backbone. The results obtained on the test dataset were DSC=0.9304 and IoU=0.9122.
Internet of Drones: Routing Algorithms, Techniques and Challenges
Authors: Haider Syed Kamran , Nauman Ali , Jamshed Muhammad Ali , Jiang Aimin , Batool Sahar , Kim Sung Won
Published: April 2022

In the past decades, unmanned aerial vehicles (UAVs), also known as drones, have drawn more attention in the academic domain and exploration in the research fields of wireless sensor networks (WSNs). Moreover, applications of drones aid operations related to military support, agriculture industry, and smart Internet-of-Things (IoT). Currently, the use of drone based IoT, also known as Internet-of-Drones (IoD), and their design challenges and techniques are being probed by researchers around the globe. The placement of drones (nodes) is an important consideration in a IoD environment and is closely related to the properties of IoT. Given a base station (BS), sensor nodes (SNs) and IoT devices are designed to capture the signals transmitted by the BS and make use of internet connectivity in a manner to facilitate users. Mutual benefit can be achieved by integrating drones into IoT. The drone based cluster models are not free from challenges. Routing protocols have to be substantiated by key algorithms. Drones are designed to be specific to applications, but the underlying principles are the same. Optimization algorithms are the gateway to better accuracy, performance, and reliability. This article discusses some of these optimization algorithms, include genetic algorithm (GA), bee optimization algorithm, and Chicken Swarm Optimization Clustering Algorithm (CSOCA). Finally, the routing schemes, protocols, and challenges in the context of IoD are discussed.
Driver Response Time and Age Impact on the Reaction Time of Drivers: A Driving Simulator Study among Professional-Truck Drivers
Authors: Poliak Milos , Svabova Lucia , Benus Jan , Demirci Ebru
Published: April 2022

Drivers’ response time means that drivers act after a judgment is made when an emergency action signal is needed. Drivers have different feelings while driving, and the response time to sudden situations differs. The main purpose of this study was to verify whether the mean reaction time of professional drivers is at the level of one second, which is the value usually used for practical purposes, and to verify the impact of age on the reaction times of drivers. Two different studies with a total of 120 participants—professional drivers—were conducted on the simulator, with 116 drivers participating in the first experiment and four drivers participating in the second experiment using eye-tracking technology. The determination of the mean reaction time was realized using statistical tests. The evaluation of the impact of age on the reaction time of professional drivers was carried out using statistical testing, a regression model, and clustering. The results of this study can be immediately used in practice for professional drivers, as the mean reaction time is usually used as a benchmark in several calculations in transport, for forensic and educational purposes, and for planning traffic and modelling different traffic situations.
C2 Cubic Algebraic Hyperbolic Spline Interpolating Scheme by Means of Integral Values
Authors: Eddargani Salah , Oraiche Mohammed , Lamnii Abdellah , Louzar Mohamed
Published: April 2022

In this paper, a cubic Hermite spline interpolating scheme reproducing both linear polynomials and hyperbolic functions is considered. The interpolating scheme is mainly defined by means of integral values over the subintervals of a partition of the function to be approximated, rather than the function and its first derivative values. The scheme provided is C2 everywhere and yields optimal order. We provide some numerical tests to illustrate the good performance of the novel approximation scheme.
An Accelerated Convex Optimization Algorithm with Line Search and Applications in Machine Learning
Authors: Chumpungam Dawan , Sarnmeta Panitarn , Suantai Suthep
Published: April 2022

In this paper, we introduce a new line search technique, then employ it to construct a novel accelerated forward–backward algorithm for solving convex minimization problems of the form of the summation of two convex functions in which one of these functions is smooth in a real Hilbert space. We establish a weak convergence to a solution of the proposed algorithm without the Lipschitz assumption on the gradient of the objective function. Furthermore, we analyze its performance by applying the proposed algorithm to solving classification problems on various data sets and compare with other line search algorithms. Based on the experiments, the proposed algorithm performs better than other line search algorithms.
Interval-Based Computation of the Uncertainty in the Mechanical Properties and the Failure Analysis of Unidirectional Composite Materials
Authors: Sotiropoulos Dimitris G. , Tserpes Konstantinos
Published: April 2022

An interval-based method is presented to evaluate the uncertainty in the computed mechanical properties and the failure assessment of composite unidirectional (UD) laminates. The method was applied to two composite laminates: a carbon/epoxy and a glass/epoxy. The mechanical properties of the UD lamina were derived using simplified micromechanical equations. An uncertainty level of ±5% was assumed for the input properties of the constituents. The global minimum and maximum values of the properties were computed using an interval branch-and-bound algorithm. Interval arithmetic operations were used to evaluate the uncertainty in the Hashin-type failure criteria in a closed form. Using the closed-form uncertainties of intervals and sets of stresses obtained by finite element analysis, the uncertainty in the failure assessment was quantified for the two composite laminates. For the assumed uncertainty level of ±5%, the computed uncertainty for the mechanical properties ranges from 6.64% to 10.63% for the carbon/epoxy material and from 6.72% to 12.28% for the glass/epoxy material. For evaluating the uncertainty effect on the efficiency of failure criteria, a probability of failure function, which employs interval boundaries, was defined and proved capable of evaluating the whole spectrum of stresses.
The Endo-α(1,3)-Fucoidanase Mef2 Releases Uniquely Branched Oligosaccharides from Saccharina latissima Fucoidans
Authors: Tran Vy Ha Nguyen , Nguyen Thuan Thi , Meier Sebastian , Holck Jesper , Cao Hang Thi Thuy , Van Tran Thi Thanh , Meyer Anne S. , Mikkelsen Maria Dalgaard
Published: April 2022

Fucoidans are complex bioactive sulfated fucosyl-polysaccharides primarily found in brown macroalgae. Endo-fucoidanases catalyze the specific hydrolysis of α-L-fucosyl linkages in fucoidans and can be utilized to tailor-make fucoidan oligosaccharides and elucidate new structural details of fucoidans. In this study, an endo-α(1,3)-fucoidanase encoding gene, Mef2, from the marine bacterium Muricauda eckloniae, was cloned, and the Mef2 protein was functionally characterized. Based on the primary sequence, Mef2 was suggested to belong to the glycosyl hydrolase family 107 (GH107) in the Carbohydrate Active enZyme database (CAZy). The Mef2 fucoidanase showed maximal activity at pH 8 and 35 °C, although it could tolerate temperatures up to 50 °C. Ca2+ was shown to increase the melting temperature from 38 to 44 °C and was furthermore required for optimal activity of Mef2. The substrate specificity of Mef2 was investigated, and Fourier transform infrared spectroscopy (FTIR) was used to determine the enzymatic activity (Units per μM enzyme: Uf/μM) of Mef2 on two structurally different fucoidans, showing an activity of 1.2 × 10−3 Uf/μM and 3.6 × 10−3 Uf/μM on fucoidans from Fucus evanescens and Saccharina latissima, respectively. Interestingly, Mef2 was identified as the first described fucoidanase active on fucoidans from S. latissima. The fucoidan oligosaccharides released by Mef2 consisted of a backbone of α(1,3)-linked fucosyl residues with unique and novel α(1,4)-linked fucosyl branches, not previously identified in fucoidans from S. latissima.
Photobiomodulation Therapy in the Treatment of Oral Mucositis—A Case Report
Authors: Jabłoński Przemysław , Musiał Mikołaj , Wiench Rafał , Stefanik Natalia , Olchowy Cyprian , Matys Jacek , Skaba Dariusz , Grzech-Leśniak Kinga
Published: April 2022

In 2021, our group published a laboratory study on the impact of PBM on human gingival fibroblasts. The in vitro results confirmed the fact that the appropriately selected wavelength and properly selected parameters of the laser settings can increase cell proliferation, modulate inflammatory markers, and decrease the susceptibility of human gingival fibroblasts to apoptosis. Therefore, this case report was aimed at the clinical evaluation of the proposed settings and treatment regimen in a very difficult situation of an immunocompromised patient with extensive changes and stagnation of symptoms for many weeks. A 65-year-old man, during his oncological treatment, was diagnosed with oral mucositis grade 3 according to the World Health Organization and National Cancer Institute scales. Due to pain sensation, long-lasting and not healing oral lesions, and problems with solid food intake, he was qualified for laser photobiomodulation therapy. For the management of oral lesions, a diode laser 635 nm (SmartMPro, Lasotronix, Poland) was intraorally applied at an energy density of 4 J/cm2, the 20 s of irradiation, the output power of 100 mW, and in continuous wave mode. Seven treatment procedures were performed two times a week using the spot technique in contact and non-contact mode. Within 21 days of monotherapy, all ailments disappeared. The patient was also able to reuse dental dentures and return to a solid diet. The obtained results confirm the efficiency of at least 3 PBM protocols. Our case shows that the use of PMB therapy contributes to faster healing of painful oral lesions in oncological patients, and thus the treatment time and return to the appropriate quality of life is shorter.
Managing the Systemic Impact of Periodontitis
Authors: Mainas Giuseppe , Ide Mark , Rizzo Manfredi , Magan-Fernandez Antonio , Mesa Francisco , Nibali Luigi
Published: April 2022

Periodontitis is a microbially driven host-mediated disease that leads to loss of periodontal attachment and bone. It is associated with elevation of systemic inflammatory markers and with the presence of systemic co-morbidities. Furthermore, periodontal treatment leads to a 24–48 h-long acute local and systemic inflammatory response. This systemic response might increase the burden of patients with compromised medical history and/or uncontrolled systemic diseases. The correlation between periodontitis and systemic diseases, the impact of periodontitis on the quality of life and public health, the effects of periodontal treatment on systemic health and disease, and the available methods to manage systemic inflammation after periodontal therapy are discussed. The main focus then shifts to a description of the existing evidence regarding the impact of periodontitis and periodontal treatment on systemic health and to the identification of approaches aiming to reduce the effect of periodontitis on systemic inflammation.
Frequency and Severity of Ear–Nose–Throat (ENT) Symptoms during COVID-19 Infection
Authors: Zięba Natalia , Lisowska Grażyna , Dadok Adam , Kaczmarek Joanna , Stryjewska-Makuch Grażyna , Misiołek Maciej
Published: April 2022

Background and Objectives: Coronavirus disease 2019 (COVID-19) is a new disease entity caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The main symptoms of infection at the onset of the pandemic include dyspnea, cough and high fever. Ear–nose–throat (ENT) symptoms are among the ones presented by patients in the course of infection. The aim of the study was to analyze the frequency of ENT symptoms and to assess their severity and duration in COVID-19 patients. Materials and Methods: The study included 337 patients who had been infected with SARS-CoV-2, as confirmed by a PCR test. The study participants were >18 years old; the mean age was 43.98 years ± 13.47 SD. The convalescents completed a questionnaire that contained 26 questions, including 9 detailed questions related to ENT symptoms, such as sore throat, vertigo, dizziness, hearing disorders, olfactory disorders, taste disturbance, headache, cough and dyspnea. The severity of symptoms was assessed using a Visual Analogue Scale (VAS). Results: The most reported ENT symptoms were olfactory disorders, which occurred in 72% of patients. The second most frequent symptom was taste disturbance (68%), VAS = 6.79 ± 3.01. Vertigo and dizziness were reported by 34% of respondents (VAS = 4.01 ± 2.01). Tinnitus was observed in 15% of patients, VAS = 3.87 ± 1.98; 14% of the subjects reported hearing impairment (VAS = 3.81 ± 2.37). Conclusions: Symptoms related to the sense of smell, taste and hearing are some of the most common symptoms in the course of COVID-19, which is important in the therapeutic and epidemiological management of patients. Delayed diagnosis and treatment of symptoms, especially those related to the hearing organ, may result in greater permanent damage.
Numerical Investigation of Diffusioosmotic Flow in a Tapered Nanochannel
Authors: Chanda Sourayon , Tsai Peichun Amy
Published: April 2022

Diffusioosmosis concerns ionic flow driven by a concentration difference in a charged nano-confinement and has significant applications in micro/nano-fluidics because of its nonlinear current-voltage response, thereby acting as an active electric gating. We carry out a comprehensive computation fluid dynamics simulation to investigate diffusioosmotic flow in a charged nanochannel of linearly varying height under an electrolyte concentration gradient. We analyze the effects of cone angle (α), nanochannel length (l) and tip diameter (dt), concentration difference (Δc = 0–1 mM), and external flow on the diffusioosmotic velocity in a tapered nanochannel with a constant surface charge density (σ). External flow velocity (varied over five orders of magnitude) shows a negligible influence on the diffusioosmotic flow inside the tapered nanochannel. We observed that a cone angle causes diffusioosmotic flow to move towards the direction of increasing gap thickness because of stronger local electric field caused by the overlapping of electric double layers near the smaller orifice. Moreover, the magnitude of average nanoflow velocity increases with increasing |α|. Flow velocity at the nanochannel tip increases when dt is smaller or when l is greater. In addition, the magnitude of diffusioosmotic velocity increases with increasing Δc. Our numerical results demonstrate the nonlinear dependence of tapered, diffusioosmotic flow on various crucial control parameters, e.g., concentration difference, cone angle, tip diameter, and nanochannel length, whereas an insignificant relationship on flow rate in the low Peclet number regime is observed.
The Suitability of Latex Particles to Evaluate Critical Process Parameters in Steric Exclusion Chromatography
Authors: Eilts Friederike , Steger Marleen , Lothert Keven , Wolff Michael W.
Published: April 2022

The steric exclusion chromatography (SXC) is a rather new method for the purification of large biomolecules and biological nanoparticles based on the principles of precipitation. The mutual steric exclusion of a nonionic organic polymer, i.e., polyethylene glycol (PEG), induces target precipitation and leads to their retention on the chromatographic stationary phase. In this work, we investigated the application of latex particles in the SXC by altering the particle’s surface charge as well as the PEG concentration and correlated both with their aggregation behavior. The parameters of interest were offline precipitation kinetics, the product recovery and yield, and the chromatographic column blockage. Sulfated and hydroxylated polystyrene particles were first characterized concerning their aggregation behavior and charge in the presence of PEG and different pH conditions. Subsequently, the SXC performance was evaluated based on the preliminary tests. The studies showed (1) that the SXC process with latex particles was limited by aggregation and pore blockage, while (2) not the aggregate size itself, but rather the aggregation kinetics dominated the recoveries, and (3) functionalized polystyrene particles were only suitable to a limited extent to represent biological nanoparticles of comparable size and charge.
New Low-Cost Ceramic Microfiltration Membranes for Bacteria Removal
Authors: Mountoumnjou Olivier , Szymczyk Anthony , Lyonga Mbambyah Emilia Enjema , Njoya Dayirou , Elimbi Antoine
Published: April 2022

Safe water provision in low-income countries is constrained by limited financial resources, and the problem is worsened during natural disasters. Thus, there is a need to develop efficient low-cost technologies for point-of-use water treatment. This work reports on the development of new ceramic microfiltration membranes made from mixtures of inexpensive raw materials available locally (kaolin, bentonite and limestone) and their efficiency in rejecting bacteria such as Escherichia coli and Staphylococcus aureus. Thermogravimetric analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, X-ray diffraction, mercury intrusion porosimetry, flexural strength and water uptake were used to characterize the raw materials and membranes. The addition of limestone in the membrane fabrication increased the pore size, the porosity and, thus, the permeability of the membranes but at the expense of the rejection performance. Among the different compositions studied, the membrane made of 83% kaolin, 10% bentonite and 7% limestone showed the best performance compromise with water permeability of 566 L·h−1·m−2·bar−1 and 100% rejection of both Escherichia coli and Staphylococcus aureus. These new low-cost microfiltration membranes are expected to have potential applications in water treatment and household applications.
Molecular Dynamics Simulations of Xe Behaviors at the Grain Boundary in UO2
Authors: Xia Yaping , Wang Zhen , Wang Li , Chen Yangchun , Liu Zhixiao , Wang Qingqing , Wu Lu , Deng Huiqiu
Published: April 2022

In this study, we investigated the behavior of xenon (Xe) bubbles in uranium dioxide (UO2) grain boundaries using molecular dynamics simulations and compared it to that in the UO2 bulk. The results show that the formation energy of Xe clusters at the Σ5 grain boundaries (GBs) is much lower than in the bulk. The diffusion activation energy of a single interstitial Xe atom at the GBs was approximately 1 eV lower than that in the bulk. Furthermore, the nucleation and growth of Xe bubbles in the Σ5 GBs at 1000 and 2000 K were simulated. The volume and pressure of bubbles with different numbers of Xe atoms were simulated. The bubble pressure dropped with increasing temperature at low Xe concentrations, whereas the volume increased. The radial distribution function was computed to explore the configuration evolution of Xe bubbles. The bubble structures in the GB and bulk material at the same temperature were also compared. Xe atoms were more regular in the bulk, whereas multiple Xe atoms formed a planar structure at the GBs.
Precipitation Behavior and Microstructural Evolution of α Phase during Hot Deformation in a Novel β-Air-Cooled Metastable β-Type Ti-B12 Alloy
Authors: Cheng Jun , Yu Sen , Li Jinshan , Gai Jinyang , Du Zhaoxin , Dong Fuyu , Zhang Jinyong , Zhang Xiaoyong
Published: April 2022

The precipitation behavior and microstructural evolution of α phase in a novel metastable β-type Ti alloy, Ti-10Mo-6Zr-4Sn-3Nb (wt.%), during isothermal compression are investigated in this study through the use of SEM (scanning electron microscope), TEM (transmission electron microscope) (HRTEM) (high-resolution transmission electron microscopy) and EBSD techniques. The results show that some finer α precipitates are randomly distributed within the β matrix during hot deformation. The morphological characteristics of α precipitates are distinctly different from those of α precipitates during the same solution-plus-aging treatment. The volume fraction of α precipitate gradually increases with increased true strain. A large proportion of precipitated α phases are prone to be precipitated at HAGBs (high-angle grain boundaries) and LAGBs (low-angle grain boundaries) during isothermal deformation. On the contrary, only a small amount of spherical α phases is precipitated within the β grain. The crystallographic orientation relationships for most spherical α precipitates formed at LAGBs and within the β grains are similar, whereas the crystallographic orientation relationships for α precipitates at grain boundaries are significantly different. The precipitation behavior of α phase in the Ti-B12 alloy during hot compression is considerably influenced by the density of dislocations.
Microstructure and Mechanical Properties of 4343/3003/6111/3003 Four-Layer Al Clad Sheets Subjected to Different Conditions
Authors: Kang Minglong , Zhou Li , Deng Yunlai , Luo Yajun , He Maoqing , Zhang Na , Huang Zhonghua , Dong Lijun
Published: April 2022

To meet the lightweight demands of automobiles, Al composite sheets require excellent mechanical properties under the condition of minimal thickness after high-temperature brazing processing. Generally, the standard used Al brazing sheets have a low strength before and after brazing. To overcome this issue, this work develops a novel 4343/3003/6111/3003 four-layer Al clad sheet, whose microstructure and mechanical properties are systematically investigated. The results show the observable fibrous microstructure with elongated grains parallel to the rolling direction in the developed four-layer Al clad sheet of the cold-rolled and annealed states. After brazing, this fibrous microstructure transforms into coarse equiaxed grains. In addition, the 4343 layer is the brazing layer. Si is mainly distributed in the 4343 layer of the cold-rolled Al clad sheets, whereas Si penetrates into the core layer along the grain boundaries after brazing. The cold-rolled samples present a certain brittleness from fracture morphology, whereas the final annealed ones show a typical ductile fracture. Meanwhile, the typical intergranular fracture is visible after brazing. The mechanical properties of the Al clad sheets are improved after brazing, with an increase of 76% in tensile strength and 62% in yield strength, compared with the final annealed ones. The elongation is increased by 29% compared with that of the cold-rolled ones. This study provides a theoretical basis for further improvement of the strength of aluminum honeycomb panels.
Effects of Light and Temperature on the Metabolic Profiling of Two Habitat-Dependent Bloom-Forming Cyanobacteria
Authors: Mohanty Bijayalaxmi , Majedi Seyed Mohammad , Pavagadhi Shruti , Te Shu Harn , Boo Chek Yin , Gin Karina Yew-Hoong , Swarup Sanjay
Published: April 2022

Rapid proliferation of cyanobacteria in both benthic and suspended (planktonic) habitats is a major threat to environmental safety, as they produce nuisance compounds such as cytotoxins and off-flavors, which degrade the safety and quality of water supplies. Temperature and light irradiance are two of the key factors in regulating the occurrence of algal blooms and production of major off-flavors. However, the role of these factors in regulating the growth and metabolism is poorly explored for both benthic and planktonic cyanobacteria. To fill this gap, we studied the effects of light and temperature on the growth and metabolic profiling of both benthic (Hapalosiphon sp. MRB220) and planktonic (Planktothricoides sp. SR001) environmental species collected from a freshwater reservoir in Singapore. Moreover, this study is the first report on the metabolic profiling of cyanobacteria belonging to two different habitats in response to altered environmental conditions. The highest growth rate of both species was observed at the highest light intensity (100 μmol photons/m²/s) and at a temperature of 33 °C. Systematic metabolite profiling analysis suggested that temperature had a more profound effect on metabolome of the Hapalosiphon, whereas light had a greater effect in the case of Planktothricoides. Interestingly, Planktothricoides sp. SR001 showed a specialized adaptation mechanism via biosynthesis of arginine, and metabolism of cysteine and methionine to survive and withstand higher temperatures of 38 °C and higher. Hence, the mode of strategies for coping with different light and temperature conditions was correlated with the growth and alteration in metabolic activities for physiological and ecological adaptations in both species. In addition, we putatively identified a number of unique metabolites with a broad range of antimicrobial activities in both species in response to both light and temperature. These metabolites could play a role in the dominant behavior of these species in suppressing competition during bloom formation. Overall, this study elucidated novel insights into the effects of environmental factors on the growth, metabolism, and adaptation strategies of cyanobacteria from two different habitats, and could be useful in controlling their harmful effects on human health and environmental concerns.
Metabolic Profiling of the Hypothalamus of Mice during Short-Term Food Deprivation
Authors: Kim Ye Jin , Kang Dasol , Yang Hye Rim , Park Byong Seo , Tu Thai Hien , Jeong Bora , Lee Byung Ju , Kim Jae Kwang , Kim Jae Geun
Published: April 2022

Nutrient availability and utilization in hypothalamic cells are directly associated with the regulation of whole-body energy homeostasis. Thus, establishing metabolic profiling in the hypothalamus in response to metabolic shift is valuable to better understand the underlying mechanism of appetite regulation. In the present study, we evaluate the alteration of lipophilic and hydrophilic metabolites in both the hypothalamus and serum of fasted mice. Fasted mice displayed an elevated ketone body and decreased lactate levels in the hypothalamus. In support of the metabolite data, we further confirmed that short-term food deprivation resulted in the altered expression of genes involved in cellular metabolic processes, including the shuttling of fuel sources and the production of monocarboxylates in hypothalamic astrocytes. Overall, the current study provides useful information to close the gap in our understanding of the molecular and cellular mechanisms underlying hypothalamic control of whole-body energy metabolism.