bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating Ghanaian Allium Species for Anti-Infective and Resistance-Reversal Natural Product Leads to Mitigate Multidrug-Resistance in Tuberculosis
Authors: Danquah Cynthia Amaning , Tetteh Michael , Amponsah Isaac Kingsley , Mensah Abraham Yeboah , Buabeng Kwame Ohene , Gibbons Simon , Bhakta Sanjib
Published: July 2021

The bulbs of Allium species are a known source of antibacterial phytochemicals. Anti-infective, efflux pump and biofilm inhibitory activities of bulb extracts of selected Ghanaian shallots Allium cepa var aggregatum were evaluated using the HT-SPOTi assay and other whole-cell phenotypic screening techniques to determine their possible mechanisms of action. Ethanol and aqueous extracts of white A. cepa inhibited the growth of Mycobacterium smegmatis mc2 155 and Escherichia coli, respectively. The majority of the Allium extracts significantly (p < 0.05) exhibited efflux pump inhibitory activity against all the acid-fast, Gram-positive and Gram-negative strains used. Hexane and chloroform extract of the pink A. cepa and the aqueous extract of the white A. cepa significantly inhibited M. smegmatis biofilm formation. For Pseudomonas aeruginosa, the inhibition was observed at 250 µg/mL for the aqueous extract (~77.34%) and 125 µg/mL for the hexane extract (~76.51%). The results suggest that Ghanaian shallots could potentially be useful when further developed to tackle antimicrobial resistance, particularly in tuberculosis (TB).
Ursolic Acid and Related Analogues: Triterpenoids with Broad Health Benefits
Authors: Nguyen Huynh Nga , Ullevig Sarah L. , Short John D. , Wang Luxi , Ahn Yong Joo , Asmis Reto
Published: July 2021

Ursolic acid (UA) is a well-studied natural pentacyclic triterpenoid found in herbs, fruit and a number of traditional Chinese medicinal plants. UA has a broad range of biological activities and numerous potential health benefits. In this review, we summarize the current data on the bioavailability and pharmacokinetics of UA and review the literature on the biological activities of UA and its closest analogues in the context of inflammation, metabolic diseases, including liver and kidney diseases, obesity and diabetes, cardiovascular diseases, cancer, and neurological disorders. We end with a brief overview of UA’s main analogues with a special focus on a newly discovered naturally occurring analogue with intriguing biological properties and potential health benefits, 23-hydroxy ursolic acid.
Sitagliptin Modulates Oxidative, Nitrative and Halogenative Stress and Inflammatory Response in Rat Model of Hepatic Ischemia-Reperfusion
Authors: Trocha Małgorzata , Fleszar Mariusz G. , Fortuna Paulina , Lewandowski Łukasz , Gostomska-Pampuch Kinga , Sozański Tomasz , Merwid-Ląd Anna , Krzystek-Korpacka Małgorzata
Published: July 2021

A possibility of repurposing sitagliptin, a well-established antidiabetic drug, for alleviating injury caused by ischemia-reperfusion (IR) is being researched. The aim of this study was to shed some light on the molecular background of the protective activity of sitagliptin during hepatic IR. The expression and/or concentration of inflammation and oxidative stress-involved factors have been determined in rat liver homogenates using quantitative RT-PCR and Luminex® xMAP® technology and markers of nitrative and halogenative stress were quantified using targeted metabolomics (LC-MS/MS). Animals (n = 36) divided into four groups were treated with sitagliptin (5 mg/kg) (S and SIR) or saline solution (C and IR), and the livers from IR and SIR were subjected to ischemia (60 min) and reperfusion (24 h). The midkine expression (by 2.2-fold) and the free 3-nitrotyrosine (by 2.5-fold) and IL-10 (by 2-fold) concentration were significantly higher and the Nox4 expression was lower (by 9.4-fold) in the IR than the C animals. As compared to IR, the SIR animals had a lower expression of interleukin-6 (by 4.2-fold) and midkine (by 2-fold), a lower concentration of 3-nitrotyrosine (by 2.5-fold) and a higher Nox4 (by 2.9-fold) and 3-bromotyrosine (by 1.4-fold). In conclusion, IR disturbs the oxidative, nitrative and halogenative balance and aggravates the inflammatory response in the liver, which can be attenuated by low doses of sitagliptin.
Special Issue on “Natural Language Processing: Emerging Neural Approaches and Applications”
Authors: Esposito Massimo , Masala Giovanni Luca , Minutolo Aniello , Pota Marco
Published: July 2021

Nowadays, systems based on artificial intelligence are being developed, leading to impressive achievements in a variety of complex cognitive tasks, matching or even beating humans [...]
Challenges and Accomplishments in Mechanical Testing Instrumented by In Situ Techniques: Infrared Thermography, Digital Image Correlation, and Acoustic Emission
Authors: Sendrowicz Aleksander , Myhre Aleksander Omholt , Wierdak Seweryn Witold , Vinogradov Alexei
Published: July 2021

A current trend in mechanical testing technologies is to equip researchers and industrial practitioners with the facilities for non-destructive characterisation of the deformation and fracture processes occurring on different scales. The synergistic effect of such a combination of destructive and non-destructive techniques both widens and deepens existing knowledge in the field of plasticity and fracture of materials and provides the feedback sought to develop new non-destructive testing approaches and in situ monitoring techniques with enhanced reliability, accuracy and a wider scope of applications. The macroscopic standardised mechanical testing is still dominant in the research laboratories and industrial sector worldwide. The present paper reviews multiple challenges commonly faced by experimentalists, aiming at enhancing the capability of conventional mechanical testing by a combination of contemporary infrared thermography (IRT), rapid video imaging (RVI) with non-contact strain mapping possibilities enabled by the digital image correlation (DIC) method, and the acoustic emission (AE) technique providing unbeatable temporal resolution of the stochastic defect dynamics under load. Practical recommendations to address these challenges are outlined. A versatile experimental setup uniting the unique competencies of all named techniques is described alone with the fascinating possibilities it offers for the comprehensive characterisation of damage accumulation during plastic deformation and fracture of materials. The developed toolbox comprising practical hardware and software solutions brings together measuring technologies, data, and processing in a single place. The proposed methodology focuses on the characterisation of the thermodynamics, kinematics and dynamics of the deformation and fracture processes occurring on different spatial and temporal scales. The capacity of the proposed combination is illustrated using preliminary results on the tensile and fatigue behaviour of the fcc Inconel-625 alloy used as a representative example. Dissipative processes occurring in this alloy are assessed through the complex interplay between the released heat, acoustic emission waves, and expended and stored elastic energy.
Pressure–Temperature Phase Diagram of Ta-H System up to 9 GPa and 600 °C
Authors: Saitoh Hiroyuki , Takagi Shigeyuki , Sato Toyoto , Orimo Shin-ichi
Published: July 2021

High-pressure hydrogenation behaviors of pure metals have not been investigated extensively, although intense research of hydrogenation reactions under high pressure has been conducted to find novel functional hydrides. The former provides us with valuable information for the high-pressure synthesis of novel functional hydrides. A pressure–temperature phase diagram of the Ta–H system has been determined using the in situ synchrotron radiation X-ray diffraction technique below 9 GPa and 600 °C in this study. At room temperature, the phase boundary obtained between distorted bcc TaH~1 and hcp TaH~2 was consistent with the previously reported transition pressure. The experimentally obtained Clapeyron slope can be explained via the entropy change caused by hydrogen evolution from TaH~2.
A Research of Pulse Source for EFT Test of Electrical Vehicle Piles
Authors: Fan Linjing , Huang Zhengxiang , Liu Rongzhong , Pan Xuchao , Zu Xudong
Published: July 2021

A type of high-voltage pulse source technology generating double-exponential waveform pulse group was introduced. In this approach, the pulse interval could be adjusted with the step length of 100 μs, and the amplitude would reach up to 35 kV. This pulse source could be used to test the sensitivity of electric vehicle (EV) piles under electrical fast transient (EFT) interference. The theory of obtaining double-exponential wave and its generating circuit was analyzed, and then the influencing factors of the rising edge were expounded. A method of pulse insertion was adopted to generate a fast transient pulse group due to the limitation of the repeated operating frequency of switching devices. This method could be summarized as a common load fed by several parallel pulse sources, which were controlled and triggered in time sequence. Thus, a set of timing pulse could be obtained from the load ending. The feasibility of this method was also demonstrated. The electromagnetic interference cannot be avoidable because the load was fed by different timing sources. The high-voltage pulse generated initially causes the latter sources to be false-triggered with serious influence to the entire system. The interference generated by the couple circuit composed by distributed parameters, such as distributed capacitance and inductance, was also analyzed. A coupled model was established, analyzed, and simulated to prove the existence of the conducted interference and false triggering for other sources. The measure of conducted interference suppression was also presented. A set of experiments was carried out to show that different numbers of double-exponential pulse groups with different time intervals could be obtained.
Data Augmentation Methods Applying Grayscale Images for Convolutional Neural Networks in Machine Vision
Authors: Wang Jinyeong , Lee Sanghwan
Published: July 2021

In increasing manufacturing productivity with automated surface inspection in smart factories, the demand for machine vision is rising. Recently, convolutional neural networks (CNNs) have demonstrated outstanding performance and solved many problems in the field of computer vision. With that, many machine vision systems adopt CNNs to surface defect inspection. In this study, we developed an effective data augmentation method for grayscale images in CNN-based machine vision with mono cameras. Our method can apply to grayscale industrial images, and we demonstrated outstanding performance in the image classification and the object detection tasks. The main contributions of this study are as follows: (1) We propose a data augmentation method that can be performed when training CNNs with industrial images taken with mono cameras. (2) We demonstrate that image classification or object detection performance is better when training with the industrial image data augmented by the proposed method. Through the proposed method, many machine-vision-related problems using mono cameras can be effectively solved by using CNNs.
A Physical Approach to Simulate the Corrosion of Ceramic-Coated Magnesium Implants
Authors: Abdalla Moataz , Ibrahim Hamdy
Published: July 2021

Magnesium-based biodegradable materials are currently of great interest in various biomedical applications, especially those related to the treatment of bone trauma and the manufacturing of bone implants. Due to the complexity of the degradation process of magnesium, several numerical models were developed to help predict the change of the implant’s integrity in the body using in vitro tests. In this study, experimental in vitro tests and finite element methods are combined to calibrate a diffusion-based model of the uniform galvanic corrosion of high purity magnesium (HP-Mg). In addition, and for the first time, the impact of a porous coating layer generated by the Micro Arc oxidation (MAO) method is investigated and incorporated into the model. The calibrated model parameters are validated using the same immersion test conditions on a near-standard of treatment screws geometry made of HP-Mg.
Application of FTA Analysis for Calculation of the Probability of the Failure of the Pressure Leaching Process
Authors: Markulik Stefan , Šolc Marek , Petrík Jozef , Balážiková Michaela , Blaško Peter , Kliment Juraj , Bezák Martin
Published: July 2021

European Union legislation requires organizations to assess their processes in the context of risk management. The main task of risk management is to manage all risks that can significantly affect the outcome of processes. The article is focused on risk evaluation in pressure leaching at elevated temperature using the method Fault Tree Analysis (FTA). The effectivity of pyrite and arsenic pyrite decomposition by oxidative pressure leaching is influenced by the duration of the process, by the temperature, concentration of the leaching solution and by a density of the slurry. It was found that, under equitable conditions, the arsenic pyrite decomposes more intensely than pyrite. Under laboratory conditions, leaching is performed in an autoclave. Due to the aggressive environment, increased pressure and temperature, process failure is possible. Its probability was calculated by FTA. It has been found that the probability of the top event in the examined process was disproportionately high (0.057) and represents an invitation to take corrective actions. The Monte Carlo method was used for the simulation of the effect the probability of basic events on the probability of the top event—the failure of the leaching process.
Rare Earth Magnet Recycling and Materialization for a Circular Economy—A Korean Perspective
Authors: Rasheed Mohammad Zarar , Song Myung-suk , Park Sang-min , Nam Sun-woo , Hussain Javid , Kim Taek-Soo
Published: July 2021

The Republic of Korea is one of the largest consumers and a leading exporter of electronics, medical appliances, and heavy and light vehicles. Rare-earth (RE)-based magnets are indispensable for these technologies, and Korea is totally dependent on imports of compounds or composites of REEs, as the country lacks natural resources. Effect on rare earth supply chain significantly affects Korea’s transition towards a green economy. This study investigates the Republic of Korea’s approach to developing a secure rare earth supply chain for REE magnets via a recycling and materialization process known as ReMaT. It investigates the progress Korea has made so far regarding ReMaT from both technical and non-technical perspectives. Rare earth elements are successfully recycled as part of this process while experiments at the industrial scale is carried out. In this paper, the research results in terms of the extraction efficiency of rare earth elements are discussed and a comparison with previous relevant studies is provided. This study also highlights the opportunities and challenges regarding the implementation of the ReMaT process in order to create a downstream rare earth value chain based on circular economy principles.
Behavior of Quarry Rock Dust, Fly Ash and Slag Based Geopolymer Concrete Columns Reinforced with Steel Fibers under Eccentric Loading
Authors: Waqas Rana Muhammad , Butt Faheem
Published: July 2021

Geopolymer concrete, also known as an earth-friendly concrete, has been under continuous study due to its environmental benefits and a sustainable alternative to conventional concrete construction. The supplies of many source materials, such as fly ash (FA) or slag (SG), to produce geopolymer concrete (GPC) may be limited; however, quarry rock dust (QRD) wastes (limestone, dolomite, or silica powders) formed by crushing rocks appear virtually endless. Although significant experimental research has been carried out on GPC, with a major focus on the mix design development, rheological, durability, and mechanical properties of the GPC mixes; still the information available on the structural behavior of GPC is rather limited. This has implications in extending GPC application from a laboratory-based technology to an at-site product. This study investigates the structural behavior of quarry-rock-dust-incorporated fiber-reinforced GPC columns under concentric and eccentric loading. In this study, a total of 20 columns with 200 mm square cross-section and 1000 mm height were tested. The FA and SG were used as source materials to produce GPC mixtures. The QRD was incorporated as a partial replacement (20%) of SG. The conventional concrete (CC) columns were prepared as the reference specimens. The effect of incorporating quarry rock dust as a replacement of SG, steel fibers, and loading conditions (concentric and eccentric loading) on the structural behavior of GPC columns were studied. The test results revealed that quarry rock dust is an adequate material that can be used as a source material in GPC to manufacture structural concrete members with satisfactory performance. The general performance of the GPC columns incorporating QRD (20%) is observed to be similar to that of GPC columns (without QRD) and CC columns. The addition of steel fibers considerably improves the loading capacity, ductility, and axial load–displacement behavior of the tested columns. The load capacities of fiber-reinforced GPC columns were about 5–7% greater in comparison to the CC columns. The spalling of concrete cover at failure was detected in all plain GPC columns, whereas the failure mode of all fiber-reinforced GPC columns is characterized with surface cracking leading to disintegration of concrete cover.
Efficient Reversible Data Hiding Scheme for AMBTC-Compressed Images
Authors: Lin Chia-Chen , Nguyen Thai-Son , Chang Chin-Chen , Chang Wen-Chi
Published: July 2021

Reversible data hiding has attracted significant attention from researchers because it can extract an embedded secret message correctly and recover a cover image without distortion. In this paper, a novel, efficient reversible data hiding scheme is proposed for absolute moment block truncation code (AMBTC) compressed images. The proposed scheme is based on the high correlation of neighboring values in two mean tables of AMBTC-compressed images to further losslessly encode these values and create free space for containing a secret message. Experimental results demonstrated that the proposed scheme obtained a high embedding capacity and guaranteed the same PSNRs as the traditional AMBTC algorithm. In addition, the proposed scheme achieved a higher embedding capacity and higher efficiency rate than those of some previous schemes while maintaining an acceptable bit rate.
Optical Chirality Determined from Mueller Matrices
Authors: Arwin Hans , Schoeche Stefan , Hilfiker James , Hartveit Mattias , Järrendahl Kenneth , Juárez-Rivera Olga Rubi , Mendoza-Galván Arturo , Magnusson Roger
Published: July 2021

Optical chirality, in terms of circular birefringence and circular dichroism, is described by its electromagnetic and magnetoelectric material tensors, and the corresponding optical activity contributes to the Mueller matrix. Here, spectroscopic ellipsometry in the spectral range 210–1690 nm is used to address chiral phenomena by measuring Mueller matrices in transmission. Three approaches to determine chirality parameters are discussed. In the first approach, applicable in the absence of linear polarization effects, circular birefringence and circular dichroism are evaluated directly from elements of a Mueller matrix. In the second method, differential decomposition is employed, which allows for the unique separation of chirality parameters from linear anisotropic parameters as well as from depolarization provided that the sample is homogeneous along the optical path. Finally, electromagnetic modeling using the Tellegen constitutive relations is presented. The last method also allows structural effects to be included. The three methods to quantify optical chirality are demonstrated for selected materials, including sugar solutions, α-quartz, liquid crystals, beetle cuticle, and films of cellulose nanocrystals.
Experimental Assessment of Feature Extraction Techniques Applied to the Identification of Properties of Common Objects, Using a Radar System
Authors: Díez-Pastor José Francisco , Latorre-Carmona Pedro , Garrido-Labrador José Luis , Ramírez-Sanz José Miguel , Rodríguez Juan J.
Published: July 2021

Radar technology has evolved considerably in the last few decades. There are many areas where radar systems are applied, including air traffic control in airports, ocean surveillance, and research systems, to cite a few. Other types of sensors have recently appeared, which allow tracking sub-millimeter motion with high speed and accuracy rates. These millimeter-wave radars are giving rise to myriad new applications, from the recognition of the material close objects are made, to the recognition of hand gestures. They have also been recently used to identify how a person interacts with digital devices through the physical environment (Tangible User Interfaces, TUIs). In this case, the radar is used to detect the orientation, movement, or distance from the objects to the user’s hands or the digital device. This paper presents a thoughtful comparative analysis of different feature extraction techniques and classification strategies applied on a series of datasets that cover problems such as the identification of materials, element counting, or determining the orientation and distance of objects to the sensor. The results outperform previous works using these datasets, especially when the accuracy was lowest, showing the benefits feature extraction techniques have on classification performance.
Physical Vapor-Deposited Silver (Ag)-Based Metal-Dielectric Nanocomposites for Thin-Film and Coating Applications
Authors: Nur-E-Alam Mohammad , Basher Mohammad Khairul , Vasiliev Mikhail , Das Narottam
Published: July 2021

Metallic thin-film materials and nanoparticles (mainly silver (Ag)-based) are recently being used in many nano-technological applications, including sensors, reflective heat-mirror coatings, and antibacterial coatings. The physical vapor deposition technique has attracted significant attention for Ag-based nanocomposites with tailoring of the structural and optical properties of metallic thin films, thus allowing for further improvements and application possibilities in various existing fields, namely electronics, catalysis, magnetics, and optics, alongside the environment and health and new emergent fields, particularly thin-film coatings. This study highlights the preparation, characterization, properties, and possible future application directions of several types of silver (Ag)-based nanocomposite thin films prepared by using physical vapor deposition techniques. The high-temperature (above 300 °C) heat-treated composite layer shows significant spectral shifts; however, distinguishingly notable sizes of nanoparticles are not observed, which indicates that this newly developed composite material can be useful for various coating applications.
A Compute and Wait in PoW (CW-PoW) Consensus Algorithm for Preserving Energy Consumption
Authors: Kara Mostefa , Laouid Abdelkader , AlShaikh Muath , Hammoudeh Mohammad , Bounceur Ahcene , Euler Reinhardt , Amamra Abdelfattah , Laouid Brahim
Published: July 2021

Several trusted tasks use consensus algorithms to solve agreement challenges. Usually, consensus agreements are used to ensure data integrity and reliability in untrusted environments. In many distributed networking fields, the Proof of Work (PoW) consensus algorithm is commonly used. However, the standard PoW mechanism has two main limitations, where the first is the high power consumption and the second is the 51% attack vulnerability. In this paper, we look to improve the PoW consensus protocol by introducing several proof rounds. Any given consensus node should resolve the game of the current round Roundi before participating in the next round Roundi+1. Any node that resolves the game of Roundi can only pass to the next round if a predetermined number of solutions has been found by other nodes. The obtained evaluation results of this technique show significant improvements in terms of energy consumption and robustness against the 51% and Sybil attacks. By fixing the number of processes, we obtained an energy gain rate of 15.63% with five rounds and a gain rate of 19.91% with ten rounds.
Localization of LHD Machines in Underground Conditions Using IMU Sensors and DTW Algorithm
Authors: Stefaniak Paweł , Jachnik Bartosz , Koperska Wioletta , Skoczylas Artur
Published: July 2021

This article presents the concept of using the DTW algorithm to partially solve the problem of locating LHD (load, haul, dump) in an underground mine. The concept assumes the recognition of characteristics—patterns that are hidden in vibrations recorded by vehicles—in segments of the route in the underground excavation, which under appropriate conditions enables the obtainment of information similar to that obtained through the use of RFID gates. With the use of this solution in practice, there are several problems that are addressed in this article. One of the main issues is the different arrangement of the signal fragments resulting from driving along with characteristic parts of the route (bumps, paving damage, lumps of excavated material, etc.) at different driving speeds. This problem was solved by using a combination of the road quality detection algorithm and the DTW algorithm, which estimates the similarity of time series with different lengths. The concept was developed and pre-tested using a test rig and a constructed wheeled robot, and then validated in the conditions of the KGHM underground copper mine in Poland, where the readings from the typical haulage process of an LHD vehicle were analyzed.
Multiscale Content-Independent Feature Fusion Network for Source Camera Identification
Authors: You Changhui , Zheng Hong , Guo Zhongyuan , Wang Tianyu , Wu Xiongbin
Published: July 2021

In recent years, source camera identification has become a research hotspot in the field of image forensics and has received increasing attention. It has high application value in combating the spread of pornographic photos, copyright authentication of art photos, image tampering forensics, and so on. Although the existing algorithms greatly promote the research progress of source camera identification, they still cannot effectively reduce the interference of image content with image forensics. To suppress the influence of image content on source camera identification, a multiscale content-independent feature fusion network (MCIFFN) is proposed to solve the problem of source camera identification. MCIFFN is composed of three parallel branch networks. Before the image is sent to the first two branch networks, an adaptive filtering module is needed to filter the image content and extract the noise features, and then the noise features are sent to the corresponding convolutional neural networks (CNN), respectively. In order to retain the information related to the image color, this paper does not preprocess the third branch network, but directly sends the image data to CNN. Finally, the content-independent features of different scales extracted from the three branch networks are fused, and the fused features are used for image source identification. The CNN feature extraction network in MCIFFN is a shallow network embedded with a squeeze and exception (SE) structure called SE-SCINet. The experimental results show that the proposed MCIFFN is effective and robust, and the classification accuracy is improved by approximately 2% compared with the SE-SCINet network.
Proposal of Damage Index Ratio for Low- to Mid-Rise Reinforced Concrete Moment-Resisting Frame with Setback Subjected to Uniaxial Seismic Loading
Authors: Maulana Taufiq Ilham , Enkhtengis Badamkhand , Saito Taiki
Published: July 2021

A vertical irregularity setback in reinforced concrete (RC) building affects its performance and response especially subjected to earthquake ground motions. It is necessary to understand how the seismic damage is established due to setbacks and avoid damage concentration on the irregularity section. The objective of this study is to propose a formula to estimate the damage distribution along the height of the setback building from a geometric measure of the degree of irregularity. First, previous experimental tests for two types of setback buildings, a towered and a stepped setback frames, were analyzed to verify the accuracy of the frame analysis. The results of the frame analysis considerably matched the experimental test results. Furthermore, to study the relationship between the degree of setback and the distribution of damage, a parametric study was conducted using 35 reinforced concrete setback frames, consisting of models with stepped setback type and towered setback type with different degrees of setback. The inelastic dynamic analyses of all the frames under three earthquake ground motions were conducted. The irregularity indices proposed in literature were adopted to express the degree of setback and the structural damage was expressed by the Park–Ang damage index. Using nonlinear regression analysis, formulas to estimate damage index ratio between two main structure parts (tower and base) from setback indices were proposed. Finally, the proposed formula was applied to the experimental test results to confirm its validity.
Atmospheric Pressure Dielectric Barrier Discharge Plasma-Enhanced Optical Contact Bonding of Coated Glass Surfaces
Authors: Neumann Josephine , Brückner Stephan , Viöl Wolfgang , Gerhard Christoph
Published: July 2021

This paper reports on plasma-enhanced bonding of optics surfaces coated with highly sensitive functional layers using surface preparation by a dielectric barrier discharge (DBD) plasma. The samples to be bonded were treated with a DBD in diffuse mode at atmospheric pressure for 30 s which is applied directly to the sample surface, then joined with the aid of de-ionised water and cured subsequently. The plasma treatment itself already increased the shear strength achieved by a factor of two compared to classical wringing or direct contacting, while the curing process led to a further increase by a factor of up to five, depending on curing temperature. The observed enhancement of shear strength can be attributed to DBD plasma-induced cleaning and most likely additional activation of the surface as verified by contact angle measurements. Since the impact of the used plasma on the surface is quite gentle in comparison to other bonding processes or other plasma-based processes reported in the literature, a destruction of the treated functional layer is avoided. This advantage makes it possible to bond even optics surfaces coated with sensitive materials.
Ferroelectric Transition in Sr- and W-Doped BaTiO3 Solid Solutions
Authors: Ahn Heeju , Lee Eunjeong , Cho Yujin , Bae Dongyeon , Park Hee , Yang Jayoon , Cho Jiung , Cho Suyeon
Published: July 2021

We synthesized Sr- and W-doped BaTiO3 (BTO) polycrystals by using a solid-state reaction method. The X-ray diffraction results showed that Sr and W atoms occupied the Ba and Ti sites in tetragonal BTO, respectively, and there were changes in the lattice constants and the volumes in the Sr- and W-doped BTO. We found a change in the latent heat and the Curie temperature (TC) during the transition between the ferroelectric and paraelectric phases while increasing the contents of Sr and W in the Sr- and W-doped BTO. This can be explained by the fact that the doping of Sr and W atoms in BTO prevented a distinct transition between the ferroelectric tetragonal and paraelectric cubic structures by decreasing the c/a ratio to a value close to unity. This study shows a way toward a strategy for modulating a crystal structure by using proper dopants for future applications in ferroelectricity-based devices.
The Effect of Ripening Stages on the Accumulation of Carotenoids, Polyphenols and Vitamin C in Rosehip Species/Cultivars
Authors: Medveckienė Brigita , Kulaitienė Jurgita , Levickienė Dovilė , Hallmann Ewelina
Published: July 2021

Our research was aimed at assessing the effect of accumulation of carotenoids, polyphenols, vitamin C and ripening stage in the rosehip fruits of two species—Rosa canina, Rosa rugosa and two cultivar—Rosa rugosa ‘Rubra’ and Rosa rugosa ‘Alba’. The amounts of carotenoids, polyphenols and vitamin C were determined using the high-performance liquid chromatography (HPLC) method. The obtained results showed that the significantly highest amount (107.15 mg 100 g−1) of total carotenoid was determined in the fruits of Rosa canina at ripening Stage V. While results indicated that significant amount of total polyphenols were established at Stages I and II in the Rosa Rugosa ‘Alba’ and Rosa rugosa ‘Rubra’ cultivars (110.34 mg 100 g−1, 107.88 mg 100 g−1 and 103.20 mg 100 g−1 103.39 mg 100 g−1). At ripening Stage I, in the fruits of Rosa rugosa the greatest increases were established in the contents of vitamin C (3036.08 mg 100 g−1).
Chemical Enhanced Backwashing for Controlling Organic Fouling in Drinking Water Treatment Using a Novel Hollow-Fiber Polyacrylonitrile Nanofiltration Membrane
Authors: Kim Heejin , Shim Intae , Zhan Min
Published: July 2021

A novel polyacrylonitrile (PAN)-based ultrafiltration (UF) hollow-fiber membrane was newly synthesized for nanofiltration (NF) applications. This semi-fully NF hollow-fiber membrane was characterized using a variety of analysis techniques. The membrane exhibited higher negative charge and hydrophilicity and lower surface roughness compared to the pristine UF hollow-fiber membrane. Experiments to study the performance and fouling were simulated under laboratory conditions in a cross-flow system and in–out mode using organic compounds, namely, humic acid and sodium alginate. The removal efficiencies of humic acid and sodium alginate were 65% and 73%, respectively, in the pristine hollow-fiber membrane and 93% and 95%, respectively, in the proposed membrane. The flux decline by natural organic matter was less in the case of the proposed membrane compared to that in the pristine membrane. To mitigate organic fouling on the proposed membrane, sodium hypochlorite (NaClO) was used as a chemical enhanced backwashing agent. At a NaClO concentration of 1 mg/L with a backwashing time of 30 s, an optimal flux recovery of 92.1% of the initial permeability of the PAN-NF hollow-fiber membrane was achieved with less membrane degradation. The results of this study will provide practical insight and act as a technical guide for NF-based plant engineers/operators.
Laser Management of Peri-Implantitis: A Comparison between Photodynamic Therapy Combined with Hydrogen Peroxide (OHLLT) and OHLLT + Er:YAG Laser. A Retrospective Controlled Study
Authors: Caccianiga Gianluigi , Rey Gérard , Caccianiga Paolo , Leonida Alessandro , Baldoni Marco , Baldoni Alessandro , Ceraulo Saverio
Published: July 2021

In peri-implantitis, treatment lasers are effectively used to enhance implant surfaces’ decontamination of bacteria. The type of lasers commonly used and tested in dentistry are Nd:YAG, Er:YAG and diodes. The Er:YAG laser is considered to be effective in removing biofilm from implant surfaces. Photodynamic therapy (PDT), realized with low-level laser therapy (LLLT) and a photosensitizer, seems to have limited efficacy in peri-implantitis management, while diode lasers used with high frequency and power (Wiser, Doctor Smile), performed with hydrogen peroxide 10 vol. 3% (OHLLT), seems to lead to a deep sanitization of implant surfaces, without any thermal effect. The aim of our retrospective controlled study is to compare an oxygen high-level laser therapy (OHLLT) protocol with OHLLT with an Er:YAG laser (Pluser, Doctor Smile) in order to maximize bacterial removal and to evaluate if an Er:YAG laser could improve hard tissue regeneration with respect to OHLLT alone. Two hundred and ten implants affected by peri-implantitis were divided into two groups: 88 implants were treated with OHLLT alone (control group) while 122 underwent OHLLT and Er:YAG treatment (test group). Mean bone loss before (T0) and after treatment (T1) (with a follow-up of 5 years) was registered for all implants. The collected data were analyzed with the Statistical Package for Social Sciences (SPSS) version 11.5. No statistically significant differences were found. In the OHLLT group, we noticed a mean bone loss after treatment of 2.1 mm in the upper arch and 2.4 mm in the mandible. In the OHLLT + Er:YAG group, the results indicate a mean bone loss of 2.0 mm in the upper arch and 2.5 mm in the mandible. Both groups showed a mean bone loss after treatment of 2.3 mm. According to the Kolmogorov–Smirnov test, overall, data followed a normal distribution (value of the K-S test statistic = 0.0912; p = 0.36112). OHLLT plays a central role in enhancing clinical results in peri-implantitis treatment, leading to an effective bacterial decontamination. Our results showed no statistically significant differences between OHLLT and OHLLT + Er:YAG laser; thus, the potential advantageous role of Er:YAG has been downgraded with the analysis of our study.
The Influence of Carpeting, Human Activity and Number of Beds on Airborne Fungi Concentration in Hotel Bedrooms
Authors: Zapata-Morín Patricio , Reyna-Martinez Raúl , Orue Nydia , de J. Treviño-Rangel Rogelio , Elizondo-Zertuche Mariana , Adame-Rodríguez Juan , Becerra-Siller Yair , Sánchez-Ovalle Verónica , Robledo-Leal Efrén
Published: July 2021

In urban environments, people spend about 90% of their time indoors, where strong indicators of air-borne contaminants have been found. Currently, there are no reports on the fungal presence and distribution in the air of hotel bedrooms. In this study, we assessed the presence of airborne fungi in bedrooms from three hotels and correlated with room characteristics. We sampled 100 L (L) of air from hotels in Nuevo León, Mexico, then fungi colony forming units (CFU) were measured and identification was made based on morphological features. Variables considered were the presence of carpet, number of beds, cleaning status for the room and floor number. Penicillium, Cladosporium and Aspergillus exhibited the highest CFU concentration and frequency. A slight tendency was observed towards lower fungi concentrations when rooms had been cleaned before sampling. Statistical differences were found between rooms with carpet vs. no carpet, and one vs. two beds. Furthermore, a correlation between floor number and fungi concentration was observed with correspondence to the hotels’ room assignment protocol. These findings offer new variables to take into consideration when designing and implementing preventive or corrective sanitization procedures to improve their efficiency and could be relevant for hotel bedrooms as well as any other type of room.
The Effect of Different Organic Foliar Fertilization on Physiological and Chemical Characters in Hop (Humulus lupulus L., cv Cascade) Leaves and Cones
Authors: Rodolfi Margherita , Barbanti Lorenzo , Giordano Cristiana , Rinaldi Massimiliano , Fabbri Andrea , Pretti Luca , Casolari Riccardo , Beghé Deborah , Petruccelli Raffaella , Ganino Tommaso
Published: July 2021

Background: Hop cultivation requires an abundant quantity of nutrients to reach higher cone yield and quality. The aim of this work was the evaluation of different fertilization plans to obtain an improvement in product quality. Methods: Foliar analysis, anatomical analysis through the use of light microscope and SEM; physiological measurements through atLEAF, Handy PEA and spectrophotometry, were carried out to determine chlorophyll content, carotenoids and photosynthetic efficiency in two periods (t1, t2) for four experimental treatments and a Control (Treat 1, Treat 2, Treat 3, Treat 4, Untreat). Leaf texture (texture analyzer), color (colorimeter), DPPH activity (spectrophotometer), bitter acid content (HPLC-UV) and essential oil yields (steam distillation) and cone yields were measured. Results: Treat 2 showed the best performance: (i) in leaves, in terms of texture, chlorophyll content and color; (ii) in cones, with 6.98% of alpha acids, 1.78% of oil yield and 3.55 kg of fresh cones per plants. Conclusion: The fertilization plans caused alteration in micro and macro elements content in hop leaves and in the composition of hop cones. In our conditions, the best fertilization plan, in terms of cone productivity and quality, was Treat 2, highlighting the value of a customized organic foliar fertilization plan for hop cultivation.
Chicken Feather Keratin Peptides for the Control of Keratinocyte Migration
Authors: Botelho Cláudia M. , Ferreira-Santos Pedro , Toubarro Duarte , Dinis Hugo , Osório Hugo , Costa-Barbosa Augusto , Sampaio Paula , Simões Nelson , Teixeira José A.
Published: July 2021

FAO estimates that in 2030 the poultry meat production could reach 120 million tons, which is a challenge in terms of waste management. Feathers are mainly composed of keratin, an important biomaterial. Using feathers as a source of keratin will minimize the waste generated, while contributing to supply an important material for several industries, such as pharmaceutical and biomedical. The peptides were extracted from the feathers by microbial degradation. In this study, we evaluated the peptides effect on keratinocyte metabolic activity and migration. The influence of these peptides on non-activated and activated macrophages was also assessed. It was demonstrated that depending on the keratin peptide fraction in contact with keratinocytes, it is possible to modulate the migration rate of the keratinocytes. Peptide fraction with low molecular weight increases migration, while peptides with a high range of molecular sizes decreases it. Some peptide fractions induce the secretion of TNF-α in non-activated macrophages and not on activated macrophages, demonstrating that these peptides should only be placed in contact with cells, in the context of an ongoing inflammatory process. This work is a step forward on the understanding of keratin peptides influence on keratinocytes and immune cells system cells, macrophages.
Vertical to Horizontal UHS Ratios for Low to Medium Seismicity Regions with Deep Soil atop Deep Geological Sediments—An Example of the City of Osijek, Croatia
Authors: Bulajić Borko Đ. , Hadzima-Nyarko Marijana , Pavić Gordana
Published: July 2021

The severity of vertical seismic ground motions is often factored into design regulations as a component of their horizontal counterparts. Furthermore, most design codes, including Eurocode 8, ignore the impact of local soil on vertical spectra. This paper investigates vertical pseudo-absolute acceleration spectral estimates, as well as the ratios of spectral estimates for strong motion in vertical and horizontal directions, for low to medium seismicity regions with deep local soil and deep geological sediments beneath the local soil. The case study region encompasses the city of Osijek in Croatia. New regional frequency-dependent empirical scaling equations are derived for the vertical spectra. According to these equations, for a 0.3 s spectral amplitude at deep soils atop deep geological sediments compared to the rock sites, the maximum amplification is 1.48 times. The spectra of vertical components of various real strong motions recorded in the surrounding region are compared to the empirical vertical response spectra. The new empirical equations are used to construct a Uniform Hazard Spectra for Osijek. The ratios of vertical to horizontal Uniform Hazard Spectra are generated, examined, and compared to Eurocode 8 recommendations. All the results show that local soil and deep geology conditions have a significant impact on vertical ground motions. The results also show that for deep soils atop deep geological strata, Eurocode 8 can underestimate the vertical to horizontal spectral ratios by a factor of three for Type 2 spectra while overestimating them by a factor of two for Type 1 spectra.
Revisiting Low-Resolution Images Retrieval with Attention Mechanism and Contrastive Learning
Authors: Dang Thanh-Vu , Yu Gwang-Hyun , Kim Jin-Young
Published: July 2021

Recent empirical works reveal that visual representation learned by deep neural networks can be successfully used as descriptors for image retrieval. A common technique is to leverage pre-trained models to learn visual descriptors by ranking losses and fine-tuning with labeled data. However, retrieval systems’ performance significantly decreases when querying images of lower resolution than the training images. This study considered a contrastive learning framework fine-tuned on features extracted from a pre-trained neural network encoder equipped with an attention mechanism to address the image retrieval task for low-resolution image retrieval. Our method is simple yet effective since the contrastive learning framework drives similar samples close to each other in feature space by manipulating variants of their augmentations. To benchmark the proposed framework, we conducted quantitative and qualitative analyses of CARS196 (mAP = 0.8804), CUB200-2011 (mAP = 0.9379), and Stanford Online Products datasets (mAP = 0.9141) and analyzed their performances.
Optimizing the Sodium Hydroxide Conversion Using Regression Analysis in CSTR
Authors: Al Mesfer Mohammed K.
Published: July 2021

The current study deals with the maximization of NaOH conversion using step-wise regression analysis in a CSTR. The dependence of temperature, volume, agitation rate, and feed rate on reactor performance is examined as well as interaction outcome of the operating parameters. The concentration of the reactants was fixed at 0.1 M. The steady state conversion with respect to NaOH is analyzed to find the process performance. Step-wise regression analysis is used to remove an insignificant factors. The agitation rate (X2) and feed rate (X3) proved to have an insignificant influence on the reaction conversion at a significant level (α) of 5%. Consequently, the temperature (X1) and reaction volume (X4) were found to have significant effect on the reaction conversion using step-wise regression. The temperature and volume dependence on steady state NaOH conversion were described by a polynomial model of 2nd and 3rd order. A maximal steady state conversion equal to 63.15% was obtained. No improvement was found in reaction conversion with 3rd order polynomial, so the second order polynomial is considered as the optimum reaction conversion modal. It may be recommended that 2nd order regression polynomial model adequately represents the experimental data very well.
Improving Phenolic-Linked Antioxidant, Antihyperglycemic and Antibacterial Properties of Emmer and Conventional Wheat Using Beneficial Lactic Acid Bacteria
Authors: Christopher Ashish , Sarkar Dipayan , Shetty Kalidas
Published: July 2021

Beneficial lactic acid bacteria (LAB)-based fermentation is an effective bioprocessing approach to improve human-health-targeted functional benefits of plant-based food substrates, such as cereal grains. Previously, we observed high phenolic bioactive-linked antioxidant and anti-hyperglycemic properties in whole grain Emmer (hulled). In this study, beneficial LAB (Lactiplantibacillus plantarum) was recruited to ferment (0–72 h) aqueous extracts (0.4 g/mL concentration) of previously optimized hulled Emmer wheat and conventional red spring wheat cv. Barlow. The fermented and unfermented (control) wheat extracts were analyzed for phenolic content, phenolic profile, antioxidant activity, and antihyperglycemic properties (α-amylase and α-glucosidase enzyme inhibitory activity) using in vitro assay models. Additionally, antimicrobial activity against pathogenic bacteria Helicobacter pylori, and potential prebiotic activity supporting the growth of beneficial Bifidobacterium longum were also investigated. Improvement in antioxidant activity and antihyperglycemic functional benefits were observed, while soluble phenolic content remained high after 72 h fermentation. Antimicrobial activity against H. pylori was also observed in 48 and 72 h fermented wheat extracts. This study provides an insight into the efficacy of LAB-based fermentation as a safe bioprocessing tool to design health-targeted functional foods and ingredients from underutilized whole grains like Emmer for targeting type 2 diabetes dietary benefits.