bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymatic Activity as New Moorsh-Forming Process Indicators of Peatlands
Authors: Szajdak Lech W. , Meysner Teresa , Szczepański Marek
Published: January 2021

The aim of this study is to comprehensively assess the change in oxidoreductive enzyme activities, due to the potential in catalyzing oxidation and reduction reactions, as the basic processes on undrained and drained peat soils. On undrained peatlands, a significant decrease of enzyme activities was observed such as xanthine oxidase, urate oxidase, phenol oxidase, and peroxidase with an increase in depth. It was connected with significantly higher porosity values, hot water extractable organic carbon, and total organic nitrogen contents, ammonium and nitrate ions concentrations, and significantly lower ash and bulk density values in the upper layers. On drained peatlands, a significant increase of enzyme activities in depth was measured. Enzyme activities such as xanthine, urate, phenol oxidase, and peroxidase were documented to be effective as new indicators and tools for changes of the moorsh-forming process in association with the oscillation of the water table caused by the drainage of the peatlands.
Efficiency of Diagnostic Testing for Helicobacter pylori Infections—A Systematic Review
Authors: Rojas García Paula , van der Pol Simon , van Asselt Antoinette D. I. , Postma Maarten , Rodríguez-Ibeas Roberto , Juárez-Castelló Carmelo A. , González Marino , Antoñanzas Fernando
Published: January 2021

Background: The most recommended treatment for a Helicobacter pylori infection is high doses of combined antibiotics. The objective of this article is to perform a systematic review of the economic evaluation studies applied to assess the efficiency of diagnostic testing for H. pylori infections, so that their main characteristics can be identified and to learn from the literature how the antimicrobial resistance (AMR) issue is incorporated into these economic evaluations. Methods: We conducted a systematic review to compare the costs and clinical effectiveness of diagnostic strategies for H. pylori infections. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and extracted the items from the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist. Results: We found thirteen articles that were of good quality according to CHEERS: six studies focused on diagnostics of Helicobacter pylori infections associated with dyspepsia and four on duodenal ulcers. Testing was found to be the most cost-effective strategy in eight articles. Four studies considered AMR. Conclusions: Testing was more cost-effective than empirical treatment, except in cases of high prevalence (as with developing countries) or when patients could be stratified according to their comorbidities. The introduction of AMR into the model may change the efficiency of the testing strategy.
Enhanced Antimicrobial and Antibiofilm Effect of New Colistin-Loaded Human Albumin Nanoparticles
Authors: Scutera Sara , Argenziano Monica , Sparti Rosaria , Bessone Federica , Bianco Gabriele , Bastiancich Chiara , Castagnoli Carlotta , Stella Maurizio , Musso Tiziana , Cavalli Roberta
Published: January 2021

Multidrug-resistant (MDR) Gram-negative bacteria (GNB), such as Acinetobacter and Klebsiella, are responsible for severe hospital-acquired infections. Colistin, despite its toxicity and low tissue penetration, is considered the last resort antibiotic against these microorganisms. Of concern, the use of Colistin has recently been compromised by the emergence of Colistin resistance. Herein, we developed a new formulation consisting of multifunctional chitosan-coated human albumin nanoparticles for the delivery of Colistin (Col/haNPs). Col/haNPs were in vitro characterized for encapsulation efficiency, drug release, stability and cytotoxicity and were evaluated for antibacterial activity against MDR GNB (Acinetobacter baumannii and Klebsiella pneumoniae). Col/haNPs showed sizes lower than 200 nm, high encapsulation efficiency (98.65%) and prolonged in vitro release of Colistin. The safety of the nanoformulation was demonstrated by a negligible cytotoxicity on human fibroblasts and hemolytic activity. Col/haNPs evidenced a high antibacterial effect with a significant decrease in MIC values compared to free Colistin, in particular against Col-resistant strains with a pronounced decline of bacterial growth over time. Moreover, Col/haNPs exhibited an inhibitory effect on biofilm formation that was 4 and 60 fold higher compared to free Colistin, respectively for Colistin susceptible and resistant A. baumannii. Our findings suggest that Col/haNPs could represent a promising Colistin nanocarrier with high antimicrobial activity on MDR GNB.
Evaluation of Antibiotic Use in Kazakhstan for the Period 2017–2019 Based on WHO Access, Watch and Reserve Classification (AWaRe 2019)
Authors: Zhussupova Gulzira , Utepova Dinara , Orazova Galiya , Zhaldybayeva Saule , Skvirskaya Galina , Tossekbayev Kanat
Published: January 2021

The purpose of this study is to conduct a comparative analysis of the consumption of antibiotics for systemic use reimbursed by the state in Kazakhstan for 2017–2019 with the Access, Watch, and Reserve classification (AWaRe 2019) of the World Health Organization (WHO). The evaluation of the consumption of antibiotics for systemic use in Kazakhstan for 2017–2019 was carried out using the ATC/DDD methodology in accordance with the WHO AWaRe classification. The study used data on all antibiotics that were centrally purchased by a single purchaser during the study period. To understand how often Access group antibiotics are taken in Kazakhstan, the top-10 most consumed antibiotics were additionally studied. The results of a comparative analysis of the antibiotics for systemic use consumption for 2017–2019 by the Access, Watch, and Reserve groups showed a negative trend of a decrease in the consumption of Access group drugs from 1.17 defined daily dose (DDDs) per 1000 inhabitants per day (DID) (39%) in 2017 to 0.59 DID (30%) in 2019. There is an increase in consumption of Watch group antibiotics from 1.84 DID (61%) in 2017 to 1.37 DID (68%) in 2019, as well as an increase in consumption of Reserve antibiotics from 0.001 DID (0.03%) to 0.4 DID (2.11%). In recent years in Kazakhstan, there has been a decrease in the consumption of Access group antibiotics. In addition, the Watch group antibiotics are widely consumed with a certain upward trend. In 2019, one Reserve antibiotic was included in the top-10 most commonly consumed antibiotics. There is a predominant consumption of parenteral forms of antibiotics for systemic use in the country.
Hypoglycemic Effect of Resveratrol: A Systematic Review and Meta-Analysis
Authors: García-Martínez Beatriz Isabel , Ruiz-Ramos Mirna , Pedraza-Chaverri José , Santiago-Osorio Edelmiro , Mendoza-Núñez Víctor Manuel
Published: January 2021

Resveratrol (RV) is a polyphenolic compound with antioxidant, anti-inflammatory, and hypoglycemic properties. Several in vitro and animal model studies have demonstrated the beneficial effects of RV; however, the results in humans are not conclusive. After a search of different databases, 32 studies were selected for this systematic review and 30 were included in the meta-analysis. Studies that evaluated the effect of RV on glucose, insulin, HbA1c, and insulin resistance (HOMA-IR) levels were included. A significant decrease of glucose (−5.24 mg/dL, p = 0.002) and insulin levels (−1.23 mIU/L, p = 0.0003) was observed. HbA1c and HOMA-IR did not show significant changes. Due to heterogeneity, sub-analyzes were performed. Sub-analysis by dose revealed that glucose levels improve significantly after the administration of 500–1000 mg/day of RV (−7.54 mg/dL, p = 0.002), while insulin improves with doses lower than 500 mg/day (−1.43 mIU/L, p = 0.01) and greater than 1000 mg/day (−2.12 mIU/L, p = 0.03). HbA1c and HOMA-IR remained unchanged after sub-analysis by dose. Our findings suggest that RV improves glucose and insulin levels in subjects with type 2 diabetes mellitus (T2DM) and aged 45–59 years, regardless of the duration of the intervention. HbA1c improves with interventions ≥3 months. HOMA-IR does not exhibit significant changes after RV administration.
UPLC-ESI-Q-TOF-MS-Based Metabolite Profiling, Antioxidant and Anti-Inflammatory Properties of Different Organ Extracts of Abeliophyllum distichum
Authors: Yoo Tong-Kewn , Jeong Won Tae , Kim Jun Gu , Ji Hyo Seong , Ahn Min-A , Chung Jong-Wook , Lim Heung Bin , Hyun Tae Kyung
Published: January 2021

Plant extracts have gained more attention as natural therapeutic agents against inflammation characterized by an overproduction of several inflammatory mediators such as reactive oxygen species and pro-inflammatory cytokines. Although Abeliophyllum distichum Nakai is generally known for its ornamental value, recent pharmacological research has demonstrated its potential therapeutic properties. Thus, to further evaluate the applicability of A. distichum in the food, cosmetic, and medical industries, we identified the phytochemicals in three organ extracts (fruits: AF, branches: AB, leaves: AL) of A. distichum and determined their antioxidant and anti-inflammatory activities. Using UPLC-ESI-Q-TOF-MS, a total of 19 compounds, including dendromoniliside D, forsythoside B, isoacteoside, isomucronulatol 7-O-Glucoside, plantamajoside, and wighteone were identified in the A. distichum organ extracts. AB exhibited a strong reducing power, an oxygen radical antioxidant capacity, and radical scavenging values compared with other samples, whereas AL exhibited the best anti-inflammatory properties. Gene expression, western blot, and molecular docking analyses suggested that the anti-inflammatory effect of AL was mediated by its ability to suppress lipopolysaccharide (LPS)-induced production of reactive oxygen species and/or inhibit LPS-stimulated activation of extracellular signal-regulated protein kinases (ERK1/2) in RAW264.7 cells. Collectively, these results indicate that AL is a potential source of phytochemicals that could be used to treat inflammation-associated diseases.
Antioxidant Activity in Bee Products: A Review
Authors: Martinello Marianna , Mutinelli Franco
Published: January 2021

Bee products have been used since ancient times both for their nutritional value and for a broad spectrum of therapeutic purposes. They are deemed to be a potential source of natural antioxidants that can counteract the effects of oxidative stress underlying the pathogenesis of many diseases. In view of the growing interest in using bioactive substances from natural sources to promote health and reduce the risk of developing certain illnesses, this review aims to update the current state of knowledge on the antioxidant capacity of bee products such as honey, pollen, propolis, beeswax, royal jelly and bee venom, and on the analytical methods used. The complex, variable composition of these products and the multitude of analytical methods used to study their antioxidant activities are responsible for the wide range of results reported by a plethora of available studies. This suggests the need to establish standardized methods to more efficiently evaluate the intrinsic antioxidant characteristics of these products and make the data obtained more comparable.
Pharmacological and Antioxidant Activities of Rhus coriaria L. (Sumac)
Authors: Alsamri Halima , Athamneh Khawlah , Pintus Gianfranco , Eid Ali H. , Iratni Rabah
Published: January 2021

Rhus coriaria L. (Anacardiaceae), commonly known as sumac, is a commonly used spice, condiment, and flavoring agent, especially in the Mediterranean region. Owing to its bountiful beneficial values, sumac has been used in traditional medicine for the management and treatment of many ailments including hemorrhoids, wound healing, diarrhea, ulcer, and eye inflammation. This plant is rich in various classes of phytochemicals including flavonoids, tannins, polyphenolic compounds, organic acids, and many others. By virtue of its bioactive, Rhus coriaria possesses powerful antioxidant capacities that have ameliorative and therapeutic benefits for many common diseases including cardiovascular disease, diabetes, and cancer. This review describes the phytochemical properties of R. coriaria and then focuses on the potent antioxidant capacities of sumac. We then dissect the cellular and molecular mechanisms of sumac’s action in modulating many pathophysiological instigators. We show how accumulating evidence supports the antibacterial, antinociceptive, antidiabetic, cardioprotective, neuroprotective, and anticancer effects of this plant, especially that toxicity studies show that sumac is very safe to consume by humans and has little toxicity. Taken together, the findings we summarize here support the utilization of this plant as an attractive target for drug discovery.
Evaluation of Cysteine Metabolism in the Rat Liver and Kidney Following Intravenous Cocaine Administration and Abstinence
Authors: Kowalczyk-Pachel Danuta , Iciek Małgorzata , Bilska-Wilkosz Anna , Górny Magdalena , Jastrzębska Joanna , Kamińska Kinga , Dudzik Paulina , Filip Małgorzata , Lorenc-Koci Elżbieta
Published: January 2021

Many toxic effects of cocaine are attributed to reactive oxygen species (ROS) generated during its metabolism. Recently, it has been suggested that the biological action of ROS is often confused with endogenously generated reactive sulfur species (RSS). The aim of this study was to evaluate the impact of cocaine on thiols and RSS in the rat liver and kidney in the drug self-administration (SA) paradigm and the cocaine yoked delivery model (YC) followed by drug abstinence with extinction training. The level of thiols as well as RSS formed during anaerobic metabolism of cysteine and sulfate were assayed. In addition, the activity of enzymes involved in RSS formation and glutathione metabolism were determined. In the liver, following direct cocaine administration (SA and YC), the RSS levels decreased, while in the kidneys, cocaine increased the RSS contents in both groups. These changes were maintained in these tissues during drug abstinence. The level of sulfates was changed by cocaine only in the liver. In the kidney, cocaine shifted cysteine metabolism towards an anaerobic pathway. Our study demonstrates for the first time the changes in cysteine metabolism and thiol levels in the liver and kidney of rats after cocaine self-administration and abstinence.
InstaDam: Open-Source Platform for Rapid Semantic Segmentation of Structural Damage
Authors: Hoskere Vedhus , Amer Fouad , Friedel Doug , Yang Wanxian , Tang Yu , Narazaki Yasutaka , Smith Matthew D. , Golparvar-Fard Mani , Spencer Billie F.
Published: January 2021

The tremendous success of automated methods for the detection of damage in images of civil infrastructure has been fueled by exponential advances in deep learning over the past decade. In particular, many efforts have taken place in academia and more recently in industry that demonstrate the success of supervised deep learning methods for semantic segmentation of damage (i.e., the pixel-wise identification of damage in images). However, in graduating from the detection of damage to applications such as inspection automation, efforts have been limited by the lack of large open datasets of real-world images with annotations for multiple types of damage, and other related information such as material and component types. Such datasets for structural inspections are difficult to develop because annotating the complex and amorphous shapes taken by damage patterns remains a tedious task (requiring too many clicks and careful selection of points), even with state-of-the art annotation software. In this work, InstaDam—an open source software platform for fast pixel-wise annotation of damage—is presented. By utilizing binary masks to aid user input, InstaDam greatly speeds up the annotation process and improves the consistency of annotations. The masks are generated by applying established image processing techniques (IPTs) to the images being annotated. Several different tunable IPTs are implemented to allow for rapid annotation of a wide variety of damage types. The paper first describes details of InstaDam’s software architecture and presents some of its key features. Then, the benefits of InstaDam are explored by comparing it to the Image Labeler app in Matlab. Experiments are conducted where two employed student annotators are given the task of annotating damage in a small dataset of images using Matlab, InstaDam without IPTs, and InstaDam. Comparisons are made, quantifying the improvements in annotation speed and annotation consistency across annotators. A description of the statistics of the different IPTs used for different annotated classes is presented. The gains in annotation consistency and efficiency from using InstaDam will facilitate the development of datasets that can help to advance research into automation of visual inspections.
Mobility Patterns of Students: Evidence from Tricity Area, Poland
Authors: Szmelter-Jarosz Agnieszka , Suchanek Michał
Published: January 2021

Generational change is one of the vital socioeconomic forces affecting the global economic environment. In many studies, the youngest generations are presented as the ones changing the market trends. This can also be observed in areas of travel demand and mobility patterns. However, research on those topics in many countries, for many societies, is scarce. This study aimed to examine the travel behavior of Polish young adults, namely students living in the Tricity area. Factor analysis and ANOVA were used to analyze the data gathered via an online survey assessing the characteristics of mobility patterns of students born between 1981 and 1999. Factor analysis allowed grouping the attitudes towards traveling among those young adults (Y Generation, Y’s, Y Gen). Three factors were identified, and they were associated with luxury and self-expression, freedom and comfort, safety and environmental friendliness. The driver’s characteristics were the least consistent with the classic image of typical Y’s, and those using the active commute—the most. In turn, the largest group were people using public transport, which partially presented convergent opinions with drivers and users of the active commute. It turned out that the car drivers, active commuters and respondents utilizing public transport differed not only in their behavior and presentation of Y Gen characteristics but also in their attitude towards categories such as comfort, desire for luxury, economy or ecology. This study is a complex analysis of the mobility patterns of students in the Tricity area. It presents the set of variables influencing the travel demand of the chosen age group. The study also compares the presented travel choices with those declared by representatives of other nations. Finally, it indicates the next research problems to be addressed in future research.
Students’ Behavior and Perceptions Regarding Complementary Videos for Introductory Physics Courses in an Online Environment
Authors: Perez-Navarro Antoni , Garcia Victor , Conesa Jordi
Published: January 2021

Digital videos have an important and increasing presence in student learning. They play a key role especially in subjects with high mathematical content, such as physics. However, creating videos is a time-consuming activity for teachers, who are usually not experts in video creation. Therefore, it is important to know which kinds of videos are perceived as more useful by students and why. In this paper we analyze students’ perception of videos in an introductory physics course of engineering with over 200 first year students in a 100% online university, Universitat Oberta de Catalunya (UOC). Students had 142 videos available of several types. We followed a qualitative methodology from a ground theory perspective and performed semi-structured interviews. Results show that students found videos as the most valued resource, although they considered that videos cannot substitute text documents. Students valued human elements and found them in videos where the hands of the professor appear. Finally, students consumed videos according to the course schedule, visualized the whole video the first time, and consumed it later according to further deliveries and exams. The main contributions of this paper were analyzing the perception of students from a qualitative perspective in an introductory course of physics in engineering, obtaining the main elements that make videos useful for students and showing that videos with hands are valued by students.
Combined Untargeted and Targeted Fingerprinting by Comprehensive Two-Dimensional Gas Chromatography to Track Compositional Changes on Hazelnut Primary Metabolome during Roasting
Authors: Cialiè Rosso Marta , Stilo Federico , Bicchi Carlo , Charron Melanie , Rosso Ginevra , Menta Roberto , Reichenbach Stephen E. , Weinert Christoph H. , Mack Carina I. , Kulling Sabine E. , Cordero Chiara
Published: January 2021

This study focuses on the detectable metabolome of high-quality raw hazelnuts (Corylus avellana L.) and on its changes after dry-roasting. Informative fingerprinting was obtained by comprehensive two-dimensional gas chromatography with fast-scanning quadrupole mass spectrometry (GC×GC-qMS) combined with dedicated data processing. In particular, combined untargeted and targeted (UT) fingerprinting, based on pattern recognition by template matching, is applied to chromatograms from raw and roasted samples of Tonda Gentile Trilobata and Anakliuri hazelnuts harvested in Italy and Georgia. Lab-scale roasting was designed to develop a desirable organoleptic profile matching industrial standards. Results, based on 430 peak features, reveal that phenotype expression is markedly correlated to cultivar and pedoclimatic conditions. Discriminant components between cultivars are amino acids (valine, alanine, glycine, and proline); organic acids (citric, aspartic, malic, gluconic, threonic, and 4-aminobutanoic acids); and sugars and polyols (maltose, xylulose, xylitol, turanose, mannitol, scyllo-inositol, and pinitol). Of these, alanine, glycine, and proline have a high informational role as precursors of 2-acetyl- and 2-propionylpyrroline, two key-aroma compounds of roasted hazelnuts. Roasting has a decisive impact on metabolite patterns—it caused a marked decrease (−90%) of alanine, proline, leucine and valine, and aspartic and pyroglutamic acid and a −50% reduction of saccharose and galactose.
Platinum Based Nanoparticles Produced by a Pulsed Spark Discharge as a Promising Material for Gas Sensors
Authors: Volkov Ivan A. , Simonenko Nikolay P. , Efimov Alexey A. , Simonenko Tatiana L. , Vlasov Ivan S. , Borisov Vladislav I. , Arsenov Pavel V. , Lebedinskii Yuri Yu. , Markeev Andrey M. , Lizunova Anna A. , Mokrushin Artem S. , Simonenko Elizaveta P. , Buslov Vadim A. , Varfolomeev Andrey E. , Liu Zhifu , Vasiliev Alexey A. , Ivanov Victor V.
Published: January 2021

We have applied spark ablation technology for producing nanoparticles from platinum ingots (purity of 99.97 wt. %) as a feed material by using air as a carrier gas. A maximum production rate of about 400 mg/h was achieved with an energy per pulse of 0.5 J and a pulse repetition rate of 250 Hz. The synthesized nanomaterial, composed of an amorphous platinum oxide PtO (83 wt. %) and a crystalline metallic platinum (17 wt. %), was used for formulating functional colloidal ink. Annealing of the deposited ink at 750 °C resulted in the formation of a polycrystalline material comprising 99.7 wt. % of platinum. To demonstrate the possibility of application of the formulated ink in printed electronics, we have patterned conductive lines and microheaters on alumina substrates and 20 μm thick low-temperature co-fired ceramic (LTCC) membranes with the use of aerosol jet printing technology. The power consumption of microheaters fabricated on LTCC membranes was found to be about 140 mW at a temperature of the hot part of 500 °C, thus allowing one to consider these structures as promising micro-hotplates for metal oxide semiconductor (MOS) gas sensors. The catalytic activity of the synthesized nanoparticles was demonstrated by measuring the resistance transients of the non-sintered microheaters upon exposure to 2500 ppm of hydrogen.
3D Knee Loading during Stationary Cycling: A Comprehensive Model Development and Reliability Analysis
Authors: Kozlovič Peter , Šarabon Nejc , Fonda Borut
Published: January 2021

The main purpose of this study was to develop and validate a 3D model for calculating knee joint loads during seated cycling. A 3D inverse dynamics approach was used to calculate knee and ankle joint loads using kinematics and kinetics data. For such a model, four kinematics clusters and three pedal markers were used, integrated with a 6-component force/torque pedal dynamometer. Seven subjects performed one five-minute trial on 75% of their maximum power at fixed cadence of 85 rpms. Data from two consecutive samples of the same cycling trial (first and last minute) were used to validate the model with the mean difference between two samples, Cronbach’s alpha, intraclass correlation coefficient (ICC), and p-value. Results showed high ICC (>0.735) and internal consistency (>0.700) with no statistically significant values (p > 0.050) except for crank angle of peak anterior force and peak axial forces at the knee and minimum normal force (p = 0.010) and minimum crank angle (p = 0.010) on the pedal. Further analyses are required to validate the model between days and to test the sensitivity to mechanical constraints.
Experimental Study on the Compression Behavior of Grouted Rock with Bi-Directional Penetrating Crack
Authors: Feng Han , Zhang Xuemin , Zhou Xianshun , Ou Xuefeng , Zhang Cong , Chen Xinlei
Published: January 2021

Grouting is a common method of reinforcing fractured rock mass. The mechanical property of grouted rock is a major aspect of the reinforcement effect, which depends on the geometry of the crack, the angle (β) between the load direction and the crack, and other factors. Few studies have focused on grouted rock with bi-directional crack which can reflect well the grouting reinforcement in the stratum with developed fractures. To explore the grouting effect on fractured rock mass, uniaxial compression tests were carried out on grouted rock samples with different bidirectional widths (t) and angles cracks. The results showed that: (1) when the β was 30°, the failure mode was sliding along the interface of rock and grout, when the β was 45°, the failure mode was composite failure mode, and when the β was 0°, 60°, or 90°, the failure mode was typical intact rock failure mode; (2) when the β increased from 0° to 90°, the uniaxial compressive strength (UCS) decreased and then increased again; (3) when the β was 30°, the UCS had nothing to do with the grout thickness, and when the β was not 30°, the greater the grout thickness, the greater the compressive strength and the ultimate energy storage capacity. The test results can provide reference for grouting reinforcement construction and design in the underground excavation process.
Power Quality Analysis of the Output Voltage of AC Voltage and Frequency Controllers Realized with Various Voltage Control Techniques
Authors: Ashraf Naveed , Abbas Ghulam , Abbassi Rabeh , Jerbi Houssem
Published: January 2021

Single-phase and three-phase AC-AC converters are employed in variable speed drive, induction heating systems, and grid voltage compensation. They are direct frequency and voltage controllers having no intermediate power conversion stage. The frequency controllers govern the output frequency (low or high) in discrete steps as per the requirements. The voltage controllers only regulate the RMS value of the output voltage. The output voltage regulation is achieved on the basis of the various voltage control techniques such as phase-angle, on-off cycle, and pulse-width modulation (PWM) control. The power quality of the output voltage is directly linked with its control techniques. Voltage controllers implemented with a simple control technique have large harmonics in their output voltage. Different control techniques have various harmonics profiles in the spectrum of the output voltage. Traditionally, the evaluation of power quality concerns is based on the simulation platform. The validity of the simulated values depends on the selection of the period of a waveform. Any deficiency in the selection of the period leads to incorrect results. A mathematical analytical approach can tackle this issue. This becomes important to analytically analyze the harmonious contents generated by various switching control algorithms for the output voltage so that these results can be successfully used for power quality analysis and filtering of harmonics components through various harmonics suppression techniques. Therefore, this research is focused on the analytical computation of the harmonics coefficients in the output voltage realized through the various voltage and frequency control techniques. The mathematically computed results are validated with the simulation and experimental results.
Optimal IP Current Controller Design Based on Small Signal Stability for THD Reduction of a High-Power-Density PFC Boost Converter
Authors: Okilly Ahmed H. , Jeong Hojin , Baek Jeihoon
Published: January 2021

This paper presents an optimal design for the inner current-control loop of the continuous current conduction mode (CCM) power factor correction (PFC) stage, which can be used as the front stage of the two-stage AC/DC telecom power supply. The conventional single-phase CCM-PFC boost converter is implemented with proportional–integral (PI) controllers in both the voltage and current-control loops to regulate the output DC voltage to the specified value and to ensure the input current follows the input voltage, which offers a converter with a high-power factor (PF) and low current total harmonic distortion (THD). However, due to the slow dynamic response of the PI controller at the zero-crossing point of the input supply current, the input current cannot fully follow the input voltage, which leads to high THD. In this paper, we investigate a digitally controlled PFC converter with an optimally designed inner current-control loop using a doubly-fed control loops integral-proportional (IP) controller to reduce the THD and to offer an input current with a unity PF. For the economic design of a digitally controlled PFC converter, two isolated AC and DC voltage sensors are designed for interfacing with the microcontroller unit (MCU). PSIM software as well as experimental prototype was used to test the converter performance using the proposed designed current controllers and isolated voltage sensors. We achieved a high-power-density, digitally controlled, telecom PFC stage with a power factor more than 99% and THD of about 5.50%.
Energy Saving Strategies and On-Site Power Generation in a University Building from a Tropical Climate
Authors: Litardo Jaqueline , Palme Massimo , Hidalgo-León Rubén , Amoroso Fernando , Soriano Guillermo
Published: January 2021

This paper compares the potential for building energy saving of various passive and active strategies and on-site power generation through a grid-connected solar photovoltaic system (SPVS). The case study is a student welfare unit from a university campus located in the tropical climate (Aw) of Guayaquil, Ecuador. The proposed approach aims to identify the most effective energy saving strategy for building retrofit in this climate. For this purpose, we modeled the base line of the building and proposed energy saving scenarios that were evaluated independently. All building simulations were done in OpenStudio-EnergyPlus, while the on-site power generation was carried out using the Homer PRO software. Results indicated that the incorporation of daylighting controls accounted for the highest energy savings of around 20% and 14% in total building energy consumption, and cooling loads, respectively. Also, this strategy provided a reduction of about 35% and 43% in total building energy consumption, and cooling loads, respectively, when combined with triple low-e coating glazing and active measures. On the other hand, the total annual electric energy delivered by the SPVS (output power converter) was 66,590 kWh, from where 48,497 kWh was supplied to the building while the remaining electricity was injected into the grid.
Risk Assessment of Soil Contamination with Heavy Metals from Municipal Sewage Sludge
Authors: Latosińska Jolanta , Kowalik Robert , Gawdzik Jarosław
Published: January 2021

Sewage sludge (SS) is a by-product of processes conducted during the treatment of wastewater. It can be used in many different ways. One of them is the use of SS in agriculture as an organic fertiliser, but the main criterion for such use is the heavy metals (HMs) content. Knowledge of the total content of HMs in SS does not translate into the danger it may pose. The toxicity of metals is largely dependent on their mobility. The mobility of SS from three different wastewater treatment plants (WWTP) of the Świętokrzyskie Voivodeship, which were characterised by an increased zinc content, was examined in this study. The aim of the study was to prove whether the high level of zinc in SS actually disqualifies the possibility of its natural use. Calculations were made for five environmental hazard indicators: the geoaccumulation index of heavy metals in soil (Igeo), potential environmental risk indicator (PERI), risk assessment code (RAC), environmental risk factor (ERF), and the authors’ own environmental risk determinant (ERD) indicator. The obtained results show how important mobility analysis is when assessing the possibility of natural use of SS.
Protective Effect of Chemically Characterized Polyphenol-Rich Fraction from Apteranthes europaea (Guss.) Murb. subsp. maroccana (Hook.f.) Plowes on Carbon Tetrachloride-Induced Liver Injury in Mice
Authors: Amrati Fatima Ez-Zahra , Bourhia Mohammed , Slighoua Meryem , Boukhira Smahane , Ullah Riaz , Ezzeldin Essam , Mostafa Gamal A. E. , Grafov Andriy , Bousta Dalila
Published: January 2021

Apteranthes europaea (Guss.) Murb. subsp. maroccana (Hook.f.) Plowes (A. europaea) is a medicinal plant widely used in traditional medicines to treat various diseases including hepatic pathogenesis. This study was conducted to evaluate the protective effect of chemically characterized polyphenol-rich fraction from A. europaea on carbon tetrachloride-induced liver injury in mice. The chemical characterization of A. europaea polyphenol-rich fraction was carried out using HPLC-DAD (high-performance liquid chromatography (HPLC) with a diode-array detector (DAD)). Carbon tetrachloride (CCl4) was used to induce liver injuries in mice as described in previous works. A polyphenol-rich fraction from A. europaea was used at a dose of 50 mg/Kg to study its hepatoprotective effect. Next, histopathological and biochemical alterations were investigated. The HPLC analysis revealed the presence of several phenolic compounds: gallic acid, methyl gallate, rutin, ferulic acid, and resorcinol. Regarding the mice treated with a polyphenol-rich fraction from A. europaea up to 50 mg/Kg and carbon tetrachloride, no significant biochemical nor histological alterations occurred in their liver; meanwhile, serious biochemical and histopathological changes were noted for liver recovered from the mice treated with carbon tetrachloride only. In conclusion, A. europaea extract is a promising source of hepatoprotective agents against toxic liver injury.
Uncertainty Reduction of Unlabeled Features in Landslide Inventory Using Machine Learning t-SNE Clustering and Data Mining Apriori Association Rule Algorithms
Authors: Althuwaynee Omar F. , Aydda Ali , Hwang In-Tak , Lee Yoon-Kyung , Kim Sang-Wan , Park Hyuck-Jin , Lee Moon-Se , Park Yura
Published: January 2021

A landslide inventory, after an intense rainfall event in 1998, Southwestern Korea, was collected by digitizing aerial photographs. This left high uncertainty in the inventoried features to be verified by ground truths. To reduce the uncertainty, the photographs were reexamined, supported by the time slider in Google Earth. We observed 77 deformed slopes, which were similar in shape and texture, to the inventoried landslides. We then sought to label the observed formations based on their spatial relationship with surrounding conditions. A three-phase methodology was developed. First, an inventory of landslide, no landslide, vulnerable slopes, and unlabeled features was analyzed based on spatial cluster patterns, and then the dimension was reduced using the t-distributed stochastic neighbor embedding (t-SNE). Second, the Apriori algorithm, based on association rule mining, was used to identify common relations in the inventory using landslide antecedent factors (derived from topographic and landcover maps) that are linked to areas of unlabeled features. Third, the findings were validated using Landsat TM (Thematic mapper) and ETM+(Enhanced thematic mapper) images acquired before and after the original inventory. Current research offers practical and economical solutions (reduced reliance on paid remote sensing sensors and field survey) to labeling and classification of missing or outdated spatial attributed information.
Iterative Receiver Design for the Estimation of Gaussian Samples in Impulsive Noise
Authors: Mirbadin Anoush , Vannucci Armando , Colavolpe Giulio , Pecori Riccardo , Veltri Luca
Published: January 2021

Impulsive noise is the main limiting factor for transmission over channels affected by electromagnetic interference. We study the estimation of (correlated) Gaussian signals in an impulsive noise scenario. In this work, we analyze some of the existing, as well as some novel estimation algorithms. Their performance is compared, for the first time, for different channel conditions, including the Markov–Middleton scenario, where the impulsive noise switches between different noise states. Following a modern approach in digital communications, the receiver design is based on a factor graph model and implements a message passing algorithm. The correlation among signal samples, as well as among noise states brings about a loopy factor graph, where an iterative message passing scheme should be employed. As is well known, approximate variational inference techniques are necessary in these cases. We propose and analyze different algorithms and provide a complete performance comparison among them, showing that the expectation propagation, transparent propagation, and parallel iterative schedule approaches reach a performance close to optimal, at different channel conditions.
Performance Evaluation of a THz Pulsed Imaging System: Point Spread Function, Broadband THz Beam Visualization and Image Reconstruction
Authors: Di Fabrizio Marta , D’Arco Annalisa , Mou Sen , Palumbo Luigi , Petrarca Massimo , Lupi Stefano
Published: January 2021

Terahertz (THz) technology is a promising research field for various applications in basic science and technology. In particular, THz imaging is a new field in imaging science, where theories, mathematical models and techniques for describing and assessing THz images have not completely matured yet. In this work, we investigate the performances of a broadband pulsed THz imaging system (0.2–2.5 THz). We characterize our broadband THz beam, emitted from a photoconductive antenna (PCA), and estimate its point spread function (PSF) and the corresponding spatial resolution. We provide the first, to our knowledge, 3D beam profile of THz radiation emitted from a PCA, along its propagation axis, without the using of THz cameras or profilers, showing the beam spatial intensity distribution. Finally, we evaluate the THz image formation on a test-sample composed by a regular linen natural pattern.
Numerical Investigation of High-Purity Polarization-Entangled Photon-Pair Generation in Non-Poled KTP Isomorphs
Authors: Kim Ilhwan , Lee Donghwa , Lee Kwang Jo
Published: January 2021

We investigated the high-purity entangled photon-pair generation in five kinds of “non-poled” potassium titanyl phosphate (KTP) isomorphs (i.e., KTiOPO4, RbTiOPO4, KTiOAsO4, RbTiOAsO4, and CsTiOAsO4). The technique is based on the spontaneous parametric down-conversion (SPDC) under Type II extended phase matching (EPM), where the phase matching and the group velocity matching are simultaneously achieved between the interacting photons in non-poled crystals rather than periodically poled (PP) KTPs that are widely used for quantum experiments. We discussed both theoretically and numerically all aspects required to generate photon pairs in non-poled KTP isomorphs, in terms of the range of the beam propagation direction (or the spectral range of photons) and the corresponding effective nonlinearities and beam walk-offs. We showed that the SPDC efficiency can be increased in non-poled KTP isomorphs by 29% to 77% compared to PPKTP cases. The joint spectral analyses showed that photon pairs can be generated with high purities of 0.995–0.997 with proper pump filtering. In contrast to the PPKTP case, where the EPM is achieved only at one specific wavelength, the spectral position of photon pairs in the non-poled KTP isomorphs can be chosen over the wide range of 1883.8–2068.1 nm.
Low-Temperature Plasma as an Approach for Inhibiting a Multi-Species Cariogenic Biofilm
Authors: Figueira Leandro W. , Panariello Beatriz H. D. , Koga-Ito Cristiane Y. , Duarte Simone
Published: January 2021

This study aimed to determine how low-temperature plasma (LTP) treatment affects single- and multi-species biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii formed on hydroxyapatite discs. LTP was produced by argon gas using the kINPen09™ (Leibniz Institute for Plasma Science and Technology, INP, Greifswald, Germany). Biofilms were treated at a 10 mm distance from the nozzle of the plasma device to the surface of the biofilm per 30 s, 60 s, and 120 s. A 0.89% saline solution and a 0.12% chlorhexidine solution were used as negative and positive controls, respectively. Argon flow at three exposure times (30 s, 60 s, and 120 s) was also used as control. Biofilm viability was analyzed by colony-forming units (CFU) recovery and confocal laser scanning microscopy. Multispecies biofilms presented a reduction in viability (log10 CFU/mL) for all plasma-treated samples when compared to both positive and negative controls (p < 0.0001). In single-species biofilms formed by either S. mutans or S. sanguinis, a significant reduction in all exposure times was observed when compared to both positive and negative controls (p < 0.0001). For single-species biofilms formed by S. gordonii, the results indicate total elimination of S. gordonii for all exposure times. Low exposure times of LTP affects single- and multi-species cariogenic biofilms, which indicates that the treatment is a promising source for the development of new protocols for the control of dental caries.
Size Effect of Mesoporous Silica Nanoparticles on Pesticide Loading, Release, and Delivery in Cucumber Plants
Authors: Xu Yongbing , Xu Chunli , Huang Qiliang , Cao Lidong , Teng Feifei , Zhao Pengyue , Jia Minghong
Published: January 2021

Mesoporous silica nanoparticles (MSN) are widely used as pesticide carriers to enhance their effective utilization, since it can promote the solubility and absorption of pesticides by plants. For plants, the particle size of pesticides influences their absorption and efficacy. Herein, is our research work of the size effect of MSN on the loading, release, and delivery behavior of pyraoxystrobin (Pyr) in cucumber plants. The well-ordered Pyr-loaded carbon quantum dots-MSN (Pyr@M) with sizes of 15, 100, and 200 nm were prepared. A comparative study among different particle sizes of Pyr@M was carried out on the aspects of control release performance, loading content, uptake, and transportation performance in cucumber plants. It was found that the loading content increased as the particle size increased. The nanoparticles as carriers increased the solubility of insoluble Pyr, but the nanoparticle size had no clear difference impact on the release rate. The efficiency of the cellular uptake strongly depended on the particle size. The smaller the MSN size, the easier it was to be absorbed and transmitted by cucumber plants. Compared to the free Pyr, the upward transportation rate of Pyr from Pyr@M in plant increased by 3.5 times. These findings provide new theoretical basis to design the MSN pesticide delivery system.
Machine Learning Methods with Decision Forests for Parkinson’s Detection
Authors: Pramanik Moumita , Pradhan Ratika , Nandy Parvati , Bhoi Akash Kumar , Barsocchi Paolo
Published: January 2021

Biomedical engineers prefer decision forests over traditional decision trees to design state-of-the-art Parkinson’s Detection Systems (PDS) on massive acoustic signal data. However, the challenges that the researchers are facing with decision forests is identifying the minimum number of decision trees required to achieve maximum detection accuracy with the lowest error rate. This article examines two recent decision forest algorithms Systematically Developed Forest (SysFor), and Decision Forest by Penalizing Attributes (ForestPA) along with the popular Random Forest to design three distinct Parkinson’s detection schemes with optimum number of decision trees. The proposed approach undertakes minimum number of decision trees to achieve maximum detection accuracy. The training and testing samples and the density of trees in the forest are kept dynamic and incremental to achieve the decision forests with maximum capability for detecting Parkinson’s Disease (PD). The incremental tree densities with dynamic training and testing of decision forests proved to be a better approach for detection of PD. The proposed approaches are examined along with other state-of-the-art classifiers including the modern deep learning techniques to observe the detection capability. The article also provides a guideline to generate ideal training and testing split of two modern acoustic datasets of Parkinson’s and control subjects donated by the Department of Neurology in Cerrahpaşa, Istanbul and Departamento de Matemáticas, Universidad de Extremadura, Cáceres, Spain. Among the three proposed detection schemes the Forest by Penalizing Attributes (ForestPA) proved to be a promising Parkinson’s disease detector with a little number of decision trees in the forest to score the highest detection accuracy of 94.12% to 95.00%.
Time Reversal and Fractional Fourier Transform-Based Method for LFM Signal Detection in Underwater Multi-Path Channel
Authors: Zhang Zhichen , Wang Haiyan , Yao Haiyang
Published: January 2021

Fractional Fourier transform (FrFT) is a useful tool to detect linear frequency modulated (LFM) signal. However, the detection performance of the FrFT-based method will deteriorate drastically in underwater multi-path environment. This paper proposes a novel method based on time-reversal and fractional Fourier transform (TR-FrFT) to solve this problem. We make use of the focusing ability of time-reversal to mitigate the influence of multi-path, and then improve the detection performance of FrFT. Simulated results show that, compared to FrFT, the difference between peak value and maximum pseudo-peak value of the signal processed by TR-FrFT is improved by 8.75 dB. Lake experiments results indicate that, the difference between peak value and maximum pseudo-peak value of the signal processed by TR-FrFT is improved by 7.6 dB. The detection performance curves of FrFT and TR-FrFT detectors with simulated data and lake experiments data verify the effectiveness of proposed method.