bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a Cohort of Patients with Chronic Thromboembolic Pulmonary Hypertension from Northeastern Colombia (REHINO Study)
Authors: Fajardo-Rivero Javier Enrique , Mogollón Melissa , García-Bohórquez Diego Fernando , Villabona-Rueda Andrés , Mendoza-Herrera Tania , Ramírez-Sarmiento Alba , Bolívar-Grimaldos Fabio , Orozco-Levi Mauricio
Published: April 2021

Chronic thromboembolic disease (CTEPH) is one of the causes for developing pulmonary hypertension (PH). PH is characterized by an increase in pulmonary vascular pressure and resistance, ultimately leading to chronic overload. This study describes the clinical, functional, and hemodynamic characteristics as well as the established treatment strategy for a cohort of patients diagnosed with CTEPH in Bucaramanga, Colombia. In Colombia, PH is considered as an orphan disease with limited epidemiological data. We aim to provide useful information in order to help guide future clinical decisions for PH treatment and prevention. We conducted a cross-sectional study, obtaining clinical data from patients under follow-up, over 18 years of age, with hemodynamic confirmation of CTEPH in two pulmonary outpatient centers in Bucaramanga, Colombia between 2012 and 2018. 35 patients with diagnosis of CTEPH were included. Mean age was 52.3 ± 17.9 years. The mean time between the onset of symptoms to diagnosis was 14 months. 71% had a previous thrombotic event and 69% had functional class III and IV according to the world health organization (WHO) criteria. Most of the patients were classified as at high risk of mortality according to the European Society of Cardiology (ESC) and the European Respiratory Society (ERS/ESC) criteria and 60% were referred to undergo thromboendarterectomy. Most of the patients were under monotherapy treatment with Bosentan, the most prescribed medication in both monotherapy and dual therapy. This study identified a high number of patients in advanced stages of CETPH due to late diagnosis, related to health care limitations. This resulted in worse prognosis and quality of life. In addition, low adherence to non-pharmacological interventions was evidenced in patients who were not candidates for thromboendarterectomy despite the onset of pharmacological therapy.
Phenomapping of Patients with Primary Breast Cancer Using Machine Learning-Based Unsupervised Cluster Analysis
Authors: Ferro Sara , Bottigliengo Daniele , Gregori Dario , Fabricio Aline S. C. , Gion Massimo , Baldi Ileana
Published: April 2021

Primary breast cancer (PBC) is a heterogeneous disease at the clinical, histopathological, and molecular levels. The improved classification of PBC might be important to identify subgroups of the disease, relevant to patient management. Machine learning algorithms may allow a better understanding of the relationships within heterogeneous clinical syndromes. This work aims to show the potential of unsupervised learning techniques for improving classification in PBC. A dataset of 712 women with PBC is used as a motivating example. A set of variables containing biological prognostic parameters is considered to define groups of individuals. Four different clustering methods are used: K-means, self-organising maps, hierarchical agglomerative (HAC), and Gaussian mixture models clustering. HAC outperforms the other clustering methods. With an optimal partitioning parameter, the methods identify two clusters with different clinical profiles. Patients in the first cluster are younger and have lower values of the oestrogen receptor (ER) and progesterone receptor (PgR) than patients in the second cluster. Moreover, cathepsin D values are lower in the first cluster. The three most important variables identified by the HAC are: age, ER, and PgR. Unsupervised learning seems a suitable alternative for the analysis of PBC data, opening up new perspectives in the particularly active domain of dissecting clinical heterogeneity.
Modeling Market Order Arrivals on the German Intraday Electricity Market with the Hawkes Process
Authors: Graf von Luckner Nikolaus , Kiesel Rüdiger
Published: April 2021

We use point processes to analyze market order arrivals on the intraday market for hourly electricity deliveries in Germany in the second quarter of 2015. As we distinguish between buys and sells, we work in a multivariate setting. We model the arrivals with a Hawkes process whose baseline intensity comprises either only an exponentially increasing component or a constant in addition to the exponentially increasing component, and whose excitation decays exponentially. Our goodness-of-fit tests indicate that the models where the intensity of each market order type is excited at least by events of the same type are the most promising ones. Based on the Akaike information criterion, the model without a constant in the baseline intensity and only self-excitation is selected in almost 50% of the cases on both market sides. The typical jump size of intensities in case of the arrival of a market order of the same type is quite large, yet rather short lived. Diurnal patterns in the parameters of the baseline intensity and the branching ratio of self-excitation are observable. Contemporaneous relationships between different parameters such as the jump size and decay rate of self and cross-excitation are found.
Changes in Human Mobility under the COVID-19 Pandemic and the Tokyo Fuel Market
Authors: Aruga Kentaka
Published: April 2021

The study identifies the impact of the changes in human mobility due to the announcement of the state of emergency to cope with the COVID-19 pandemic on the Tokyo gasoline, diesel, and kerosene markets. Indices reflecting the movements in the visits to transit stations and workplaces were used to capture the changes in human mobility from February 2020 to February 2021. The linear and nonlinear ARDL (NARDL) models were applied to investigate the relationship between the changes in human mobility indices and fuel prices. Although only the kerosene price received an impact from the human mobility changes in the linear ARDL model, the NARDL model revealed that when human mobility was increasing, the fuel price was affected positively and the negative shocks in the mobility had an adverse influence on the fuel price. The results of the study imply the importance of providing subsidies when a state of emergency reduces fuel demands due to the decline in human mobility and negatively affects the fuel retail industry.
Could Air Quality Get Better during Epidemic Prevention and Control in China? An Analysis Based on Regression Discontinuity Design
Authors: Zhao Xinghua , Cheng Zheng , Jiang Chen
Published: April 2021

Though many scholars and practitioners are paying more attention to the health and life of the public after the COVID-19 outbreak, extant literature has so far failed to explore the variation of ambient air quality during this pandemic. The current study attempts to fill the gap by disentangling the causal effects of epidemic prevention on air quality in China, measured by the individual pollutant dimensionless index, from other confounding factors. Using the fixed effects model, this article finds that five air indicators, PM2.5, PM10, CO, NO2, and SO2, significantly improved during the shutdown period, with NO2 showing the most improvement. On the contrary, O3 shows an inverse pattern, that is, O3 gets worse unexpectedly. The positive impact of epidemic prevention on air quality, especially in terms of PM2.5, PM10, and NO2, become manifest five days after the resumption of labor, indicated by the result of a regression discontinuity design. These findings are still robust and consistent after the dataset of 2019 as a counterfactual sample is utilized. The findings of this paper make contributions to both environmental governance and pandemic prevention, with relevant guidelines regarding the health and life of the public and governmental behavioral management strategies discussed.
The Cadastre as a Source for the Analysis of Urbanization Dynamics. Applications in Urban Areas of Medium-Sized Inland Spanish Cities
Authors: Sánchez Ondoño Irene , Cebrián Abellán Francisco , Garcia-Gonzalez Juan Antonio
Published: April 2021

This article presents a methodological proposal using the cadastre as a tool to analyze urbanization dynamics. It is backed by an in-depth review of the related literature concerning Spain and Mediterranean Europe. The work uses the cadastre as a source of information, specifically leveraging the urban parcels and real estate obtained from the CAT files. After the data were collected, interpreted and organized, complementary statistical and cartographic methodologies and tools were used, together with the required database management. The goal of the study was to analyze the behavior of five intermediate cities and their urban areas, with the aim of comparing the construction dynamics between the cities and the municipalities located in their respective areas of influence in the period 2000–2016. The work is framed within the debate on urban sprawl, sustainability and the need for tools for town and regional planning. The main conclusion of the work reflects the necessity of a better understanding of the processes of transformation in cities, in which the use of cadastral data is key, given its reliability and updated information, despite the difficulty involved in accessing the data structure.
The Effect of Green Characteristics in Reducing the Inventory of Unsold Housing in New Residential Developments—A Case of Gyeonggi Province, in South Korea
Authors: Yoo Hayoung , Yoon Heeyeun
Published: April 2021

This study analyzes the effect of green characteristics on sales of unsold housing stock, using a multilevel growth model, in Gyeonggi Province, South Korea from 2012 to 2018. The green characteristics we estimated are external factors such as the proximity to urban parks and mountain trails located outside the housing complex and internal factors such as whether the area of communal open space within the complex exceeds a certain percentage. The results suggest that potential home-buyers are interested in green space inside rather than outside a housing complex in a suburban setting. Housing complexes with large enough communal open spaces had a 0.094 higher unsold unit ratio than complexes with small communal open spaces, but the surplus decreased more rapidly; the ratio declines by 0.028 per time unit. On the other hand, the results show no statistically significant effects of the distance to external green areas. This might be due to that public urban parks might not be an attraction to residents when forests and/or agricultural fields are in close proximity. The findings of this research will be utilized by construction companies and public institutions holding unsold units in improving their sales performance, not only in South Korea but also in other Asian regions showing a similar housing development pattern.
Lipoprotein Abnormalities in Chronic Kidney Disease and Renal Transplantation
Authors: Barbagallo Carlo Maria , Cefalù Angelo Baldassare , Giammanco Antonina , Noto Davide , Caldarella Rosalia , Ciaccio Marcello , Averna Maurizio Rocco , Nardi Emilio
Published: April 2021

Chronic kidney disease (CKD) is one of the most important risk factors for cardiovascular disease (CVD). Despite the kidney having no direct implications for lipoproteins metabolism, advanced CKD dyslipidemia is usually present in patients with CKD, and the frequent lipid and lipoprotein alterations occurring in these patients play a role of primary importance in the development of CVD. Although hypertriglyceridemia is the main disorder, a number of lipoprotein abnormalities occur in these patients. Different enzymes pathways and proteins involved in lipoprotein metabolism are impaired in CKD. In addition, treatment of uremia may modify the expression of lipoprotein pattern as well as determine acute changes. In renal transplantation recipients, the main lipid alteration is hypercholesterolemia, while hypertriglyceridemia is less pronounced. In this review we have analyzed lipid and lipoprotein disturbances in CKD and also their relationship with progression of renal disease. Hypolipidemic treatments may also change the natural history of CVD in CKD patients and may represent important strategies in the management of CKD patients.
Evaluation of Cutting-Tool Coating on the Surface Roughness and Hole Dimensional Tolerances during Drilling of Al6061-T651 Alloy
Authors: Al-Tameemi Hamza A. , Al-Dulaimi Thamir , Awe Michael Oluwatobiloba , Sharma Shubham , Pimenov Danil Yurievich , Koklu Ugur , Giasin Khaled
Published: April 2021

Aluminum alloys are soft and have low melting temperatures; therefore, machining them often results in cut material fusing to the cutting tool due to heat and friction, and thus lowering the hole quality. A good practice is to use coated cutting tools to overcome such issues and maintain good hole quality. Therefore, the current study investigates the effect of cutting parameters (spindle speed and feed rate) and three types of cutting-tool coating (TiN/TiAlN, TiAlN, and TiN) on the surface finish, form, and dimensional tolerances of holes drilled in Al6061-T651 alloy. The study employed statistical design of experiments and ANOVA (analysis of variance) to evaluate the contribution of each of the input parameters on the measured hole-quality outputs (surface-roughness metrics Ra and Rz, hole size, circularity, perpendicularity, and cylindricity). The highest surface roughness occurred when using TiN-coated tools. All holes in this study were oversized regardless of the tool coating or cutting parameters used. TiN tools, which have a lower coating hardness, gave lower hole circularity at the entry and higher cylindricity, while TiN/TiAlN and TiAlN seemed to be more effective in reducing hole particularity when drilling at higher spindle speeds. Finally, optical microscopes revealed that a built-up edge and adhesions were most likely to form on TiN-coated tools due to TiN’s chemical affinity and low oxidation temperature compared to the TiN/TiAlN and TiAlN coatings.
3D X-ray Microscopy of Ultrasonically Welded Aluminum/Fiber-Reinforced Polymer Hybrid Joints
Authors: Staab Florian , Prescher Mario , Balle Frank , Kirste Lutz
Published: April 2021

Ultrasonically welded hybrid aluminum/fiber-reinforced PEEK joints were analyzed non-destructively with an X-ray microscope. The potential and limitations of the technology as a non-destructive testing method were investigated. For a quantitative evaluation, joints with suitable and unsuitable parameters were compared. For a further comparison, geometric modifications of the joining partners were made, and the influence on the structure and process variation of the resulting hybrid joints was examined on a microscopic level. By using a tool for 3D segmentation of the composition of the joining zone, quantitative information on volume-specific proportions could be obtained and compared in relation to each other.
Validation of Stainless-Steel CHS Columns Finite Element Models
Authors: Jindra Daniel , Kala Zdeněk , Kala Jiří
Published: April 2021

Stainless-steel elements are increasingly used in a wide range of load-bearing structures due to their strength, minimal maintenance requirements, and aesthetic appearance. Their response differs from standard steels; therefore, it is necessary to choose a different procedure when creating a correct computational model. Seven groups of numerical models differing in the used formulation of elements integration, mesh density localization, nonlinear material model, and initial geometric imperfection were calibrated. The results of these advanced simulations were validated with published results obtained by an extensive experimental approach on circular hollow sections columns. With regard to the different slenderness of the cross-sections, the influence of the initial imperfection in the form of global and local loss of stability on the response was studied. Responses of all models were validated by comparing the averaged normalized ultimate loads and the averaged normalized deflections with experimentally obtained results.
A Prediction Model for the Calculation of Effective Stiffness Ratios of Reinforced Concrete Columns
Authors: Das Sourav , Mansouri Iman , Choudhury Satyabrata , Gandomi Amir H. , Hu Jong Wan
Published: April 2021

Nonlinear dynamic analyses of reinforced concrete (RC) frame buildings require the use of effective stiffness of members to capture the effect of cracked section stiffness. In the design codes and practices, the effective stiffness of RC sections is given as an empirical fraction of the gross stiffness. However, a more precise estimation of the effective stiffness is important as it affects the distribution of forces and various demands and response parameters in nonlinear dynamic analyses. In this study, an evolutionary computation method called gene expression programming (GEP) was used to predict the effective stiffness ratios of RC columns. Constitutive relationships were obtained by correlating the effective stiffness ratio with the four mechanical and geometrical parameters. The model was developed using a database of 226 samples of nonlinear dynamic analysis results collected from another study by the author. Subsequent parametric and sensitivity analyses were performed and the trends of the results were confirmed. The results indicate that the GEP model provides precise estimations of the effective stiffness ratios of the RC frames.
Mechanical and Thermal Behavior of Fibrous Carbon Materials
Authors: Karakashov Blagoj , Taghite M’Barek , Kouitat Richard , Fierro Vanessa , Celzard Alain
Published: April 2021

The ability of various commercial fibrous carbon materials to withstand stress and conduct heat has been evaluated through experimental and analytical studies. The combined effects of different micro/macro-structural characteristics were discussed and compared. Large differences in mechanical behavior were observed between the different groups or subgroups of fibrous materials, due to the different types of fibers and the mechanical and/or chemical bonds between them. The application of the Mooney–Rivlin model made it possible to determine the elastic modulus of soft felts, with a few exceptions, which were studied in-depth. The possible use of two different mechanical test methods allowed a comparison of the results in terms of elastic modulus obtained under different deformation regimes. The effective thermal conductivity of the same fibrous materials was also studied and found to be much lower than that of a single carbon fiber due to the high porosity, and varied with the bulk density and the fiber organization involving more or less thermal contact resistances. The thermal conductivity of most materials is highly anisotropic, with higher values in the direction of preferential fiber orientation. Finally, the combination of compression and transient thermal conductivity measurement techniques allowed the heat conduction properties of the commercial fibrous carbons to be investigated experimentally when compressed. It was observed that thermal conductivity is strongly affected under compression, especially perpendicular to the main fiber orientation.
Establishing the Carbonation Profile with Raman Spectroscopy: Effects of Fly Ash and Ground Granulated Blast Furnace Slag
Authors: Yue Yanfei , Wang Jing Jing , Basheer P. A. Muhammed , Bai Yun
Published: April 2021

Establishing the carbonation profile is of great significance to the prediction of the service life of reinforced concrete structures. In our previous work, Raman spectroscopy was shown to be an efficient tool for characterizing calcium carbonate (CaCO3) polymorphs and their profile in plain Portland cement (PC) matrices. However, as supplementary cementitious materials (SCMs), particularly fly ash (FA) and ground granulated blast furnace slag (GGBS), are widely used in concrete, establishing the carbonation profile without considering the possible effects of these SCMs could be of little significance to the real world. This paper, thus, investigated the effects of FA and GGBS on the working capacity and reliability of Raman spectroscopy for establishing the carbonation profile in PC blends containing SCMs. The thermogravimetry (TG) analysis was also conducted to verify the results from Raman spectroscopy. The results show that Raman spectroscopy demonstrated a good capacity for differentiating the variation of CaCO3 contents in FA or GGBS blends. However, the incorporation of FA and GGBS into the PC system caused some adverse effects on the quantification of CaCO3 by Raman spectroscopy, which could be attributed to the darker color and weak scatter nature of FA and the high content of glassy phases in GGBS.
Direct 3D Printing of Clear Orthodontic Aligners: Current State and Future Possibilities
Authors: Tartaglia Gianluca M. , Mapelli Andrea , Maspero Cinzia , Santaniello Tommaso , Serafin Marco , Farronato Marco , Caprioglio Alberto
Published: April 2021

The recent introduction of three-dimensional (3D) printing is revolutionizing dentistry and is even being applied to orthodontic treatment of malocclusion. Clear, personalized, removable aligners are a suitable alternative to conventional orthodontic appliances, offering a more comfortable and efficient solution for patients. Including improved oral hygiene and aesthetics during treatment. Contemporarily, clear aligners are produced by a thermoforming process using various types of thermoplastic materials. The thermoforming procedure alters the properties of the material, and the intraoral environment further modifies the properties of a clear aligner, affecting overall performance of the material. Direct 3D printing offers the creation of highly precise clear aligners with soft edges, digitally designed and identically reproduced for an entire set of treatment aligners; offering a better fit, higher efficacy, and reproducibility. Despite the known benefits of 3D printing and the popularity of its dental applications, very limited technical and clinical data are available in the literature about directly printed clear aligners. The present article discusses the advantages of 3D printed aligners in comparison to thermoformed ones, describes the current state of the art, including a discussion of the possible road blocks that exist such as a current lack of approved and marketed materials and limited existence of aligner specific software. The present review suggests the suitability of 3D direct printed aligners is superior to that of thermoformed manufactured aligners because of the prior’s increased accuracy, load resistance, and lower deformation. It is an overall more stable way to produce an aligner where submillimeter movements can make a difference in treatment outcome. Direct 3D printing represents a complex method to control the thickness of the aligner and therefore has a better ability to control the force vectors that are used to produce tooth movement. There is currently no other approved material on the market that can do this. The conclusion of this article is that we encourage further in vitro and in vivo studies to test these new technologies and materials.
Cybersecurity Risk Assessment in Smart City Infrastructures
Authors: Kalinin Maxim , Krundyshev Vasiliy , Zegzhda Peter
Published: April 2021

The article is devoted to cybersecurity risk assessment of the dynamic device-to-device networks of a smart city. Analysis of the modern security threats at the IoT/IIoT, VANET, and WSN inter-device infrastructures demonstrates that the main concern is a set of network security threats targeted at the functional sustainability of smart urban infrastructure, the most common use case of smart networks. As a result of our study, systematization of the existing cybersecurity risk assessment methods has been provided. Expert-based risk assessment and active human participation cannot be provided for the huge, complex, and permanently changing digital environment of the smart city. The methods of scenario analysis and functional analysis are specific to industrial risk management and are hardly adaptable to solving cybersecurity tasks. The statistical risk evaluation methods force us to collect statistical data for the calculation of the security indicators for the self-organizing networks, and the accuracy of this method depends on the number of calculating iterations. In our work, we have proposed a new approach for cybersecurity risk management based on object typing, data mining, and quantitative risk assessment for the smart city infrastructure. The experimental study has shown us that the artificial neural network allows us to automatically, unambiguously, and reasonably assess the cyber risk for various object types in the dynamic digital infrastructures of the smart city.
Aerobic Granular Sludge–Membrane BioReactor (AGS–MBR) as a Novel Configuration for Wastewater Treatment and Fouling Mitigation: A Mini-Review
Authors: Campo Riccardo , Lubello Claudio , Lotti Tommaso , Di Bella Gaetano
Published: April 2021

This mini-review reports the effect of aerobic granular sludge (AGS) on performance and membrane-fouling in combined aerobic granular sludge–membrane bioreactor (AGS–MBR) systems. Membrane-fouling represents a major drawback hampering the wider application of membrane bioreactor (MBR) technology. Fouling can be mitigated by applying aerobic granular sludge technology, a novel kind of biofilm technology characterized by high settleability, strong microbial structure, high resilience to toxic/recalcitrant compounds of industrial wastewater, and the possibility to simultaneously remove organic matter and nutrients. Different schemes can be foreseen for the AGS–MBR process. However, an updated literature review reveals that in the AGS–MBR process, granule breakage represents a critical problem in all configurations, which often causes an increase of pore-blocking. Therefore, to date, the objective of research in this sector has been to develop a stable AGS–MBR through multiple operational strategies, including the cultivation of AGS directly in an AGS–MBR reactor, the occurrence of an anaerobic-feast/aerobic-famine regime in continuous-flow reactors, maintenance of average granule dimensions far from critical values, and proper management of AGS scouring, which has been recently recognized as a crucial factor in membrane-fouling mitigation.
Water Pores in Planar Lipid Bilayers at Fast and Slow Rise of Transmembrane Voltage
Authors: Maček Lebar Alenka , Miklavčič Damijan , Kotulska Malgorzata , Kramar Peter
Published: April 2021

Basic understanding of the barrier properties of biological membranes can be obtained by studying model systems, such as planar lipid bilayers. Here, we study water pores in planar lipid bilayers in the presence of transmembrane voltage. Planar lipid bilayers were exposed to fast and slow linearly increasing voltage and current signals. We measured the capacitance, breakdown voltage, and rupture time of planar lipid bilayers composed of 1-pamitoyl 2-oleoyl phosphatidylcholine (POPC), 1-pamitoyl 2-oleoyl phosphatidylserine (POPS), and a mixture of both lipids in a 1:1 ratio. Based on the measurements, we evaluated the change in the capacitance of the planar lipid bilayer corresponding to water pores, the radius of water pores at membrane rupture, and the fraction of the area of the planar lipid bilayer occupied by water pores.planar lipid bilayer capacitance, which corresponds to water pores, water pore radius at the membrane rupture, and a fraction of the planar lipid bilayer area occupied by water pores. The estimated pore radii determining the rupture of the planar lipid bilayer upon fast build-up of transmembrane voltage are 0.101 nm, 0.110 nm, and 0.106 nm for membranes composed of POPC, POPS, and POPC:POPS, respectively. The fraction of the surface occupied by water pores at the moment of rupture of the planar lipid bilayer The fraction of an area that is occupied by water pores at the moment of planar lipid bilayer rupture is in the range of 0.1–1.8%.
Microstructure, Residual Stresses, and Strain-Rate-Dependent Deformation and Fracture Behavior of AISI 304L Joints Brazed with NiCrSiB Filler Metals
Authors: Otto Johannes L. , Penyaz Milena , Möhring Kerstin , Gerdes Lars , Schaum Thorge , Ivannikov Alexander , Schmiedt-Kalenborn Anke , Kalin Boris , Walther Frank
Published: April 2021

The knowledge of alloy–process–structure–property relationships is of particular interest for several safety-critical brazed components and requires a detailed characterization. Thus, three different nickel-based brazing filler metals were produced with varying chromium and molybdenum content and were used to braze butt joints of the austenitic stainless steel AISI 304L under vacuum. Two holding times were used to evaluate diffusion-related differences, resulting in six specimen variations. Significant microstructural changes due to the formation and location of borides and silicides were demonstrated. Using X-ray diffraction, alloy-dependent residual stress gradients from the brazing seam to the base material were determined and the thermal-induced residual stresses were shown through simulations. For mechanical characterization, impact tests were carried out to determine the impact toughness, as well as tensile tests at low and high strain rates to evaluate the strain-rate-dependent tensile strength of the brazed joints. Further thermal, electrical, and magnetic measurements enabled an understanding of the deformation mechanisms. The negative influence of brittle phases in the seam center could be quantified and showed the most significant effects under impact loading. Fractographic investigations subsequently enabled an enhanced understanding of the fracture mechanisms.
Effect of the Andean Geography and Climate on the Specialized Metabolism of Its Vegetation: The Subtribe Espeletiinae (Asteraceae) as a Case Example
Authors: Padilla-González Guillermo F. , Diazgranados Mauricio , Da Costa Fernando B.
Published: April 2021

The Andean mountains are ‘center stage’ to some of the most spectacular examples of plant diversifications, where geographic isolation and past climatic fluctuations have played a major role. However, the influence of Andean geography and climate as drivers of metabolic variation in Andean plants is poorly elucidated. Here, we studied the influence of those factors on the metabolome of the subtribe Espeletiinae (Asteraceae) using liquid chromatography coupled to high-resolution mass spectrometry data of over two hundred samples from multiple locations. Our results demonstrate that metabolic profiles can discriminate Espeletiinae taxa at different geographic scales, revealing inter- and intraspecific metabolic variations: at the country level, segregation between Colombian and Venezuelan taxa was observed; regionally, between páramo massifs; and locally, between páramo complexes. Metabolic differences in Espeletiinae were mainly explained by geographic isolation, although differences in taxonomic genera, temperature, and elevation, were also important. Furthermore, we found that different species inhabiting the same páramo complex showed stronger chemical similarities than the same species at different locations, corroborating that geographic isolation represents the main driver of metabolic change in Espeletiinae. The current study serves as a starting point to fill in the gaps in how Andean geography and climate have shaped the metabolism of its vegetation and reveal the potential of untargeted metabolomics to study the environmental physiology of plants.
Performance Optimization of Nitrogen Dioxide Gas Sensor Based on Pd-AlGaN/GaN HEMTs by Gate Bias Modulation
Authors: Nguyen Van Cuong , Kim Kwangeun , Kim Hyungtak
Published: April 2021

We investigated the sensing characteristics of NO2 gas sensors based on Pd-AlGaN/GaN high electron mobility transistors (HEMTs) at high temperatures. In this paper, we demonstrated the optimization of the sensing performance by the gate bias, which exhibited the advantage of the FET-type sensors compared to the diode-type ones. When the sensor was biased near the threshold voltage, the electron density in the channel showed a relatively larger change with a response to the gas exposure and demonstrated a significant improvement in the sensitivity. At 300 °C under 100 ppm concentration, the sensor’s sensitivities were 26.7% and 91.6%, while the response times were 32 and 9 s at VG = 0 V and VG = −1 V, respectively. The sensor demonstrated the stable repeatability regardless of the gate voltage at a high temperature.
Research on Measurement Method of Parachute Scanning Platform Based on MEMS Device
Authors: Liu Ning , Tian Tianqi , Su Zhong , Qi Wenhao
Published: April 2021

This paper studies the measurement of motion parameters of a parachute scanning platform. The movement of a parachute scanning platform has fast rotational velocity and a complex attitude. Therefore, traditional measurement methods cannot measure the motion parameters accurately, and thus fail to satisfy the requirements for the measurement of parachute scanning platform motion parameters. In order to solve these problems, a method for measuring the motion parameters of a parachute scanning platform based on a combination of magnetic and inertial sensors is proposed in this paper. First, scanning motion characteristics of a parachute-terminal-sensitive projectile are analyzed. Next, a high-precision parachute scanning platform attitude measurement device is designed to obtain the data of magnetic and inertial sensors. Then the extended Kalman filter is used to filter and observe errors. The scanning angle, the scanning angle velocity, the falling velocity, and the 2D scanning attitude are obtained. Finally, the accuracy and feasibility of the algorithm are analyzed and validated by MATLAB simulation, semi-physical simulation, and airdrop experiments. The presented research results can provide helpful references for the design and analysis of parachute scanning platforms, which can reduce development time and cost.
Non-Enzymatic Glucose Detection Based on NiS Nanoclusters@NiS Nanosphere in Human Serum and Urine
Authors: Arivazhagan Mani , Manova Santhosh Yesupatham , Maduraiveeran Govindhan
Published: April 2021

Herein, we report a non-enzymatic electrochemical glucose sensing platform based on NiS nanoclusters dispersed on NiS nanosphere (NC-NiS@NS-NiS) in human serum and urine samples. The NC-NiS@NS-NiS are directly grown on nickel foam (NF) (NC-NiS@NS-NiS|NF) substrate by a facile, and one-step electrodeposition strategy under acidic solution. The as-developed nanostructured NC-NiS@NS-NiS|NF electrode materials successfully employ as the enzyme-mimic electrocatalysts toward the improved electrocatalytic glucose oxidation and sensitive glucose sensing. The NC-NiS@NS-NiS|NF electrode presents an outstanding electrocatalytic activity and sensing capability towards the glucose owing to the attribution of great double layer capacitance, excessive electrochemical active surface area (ECASA), and high electrochemical active sites. The present sensor delivers a limit of detection (LOD) of ~0.0083 µM with a high sensitivity of 54.6 µA mM−1 cm−2 and a wide linear concentration range (20.0 µM–5.0 mM). The NC-NiS@NS-NiS|NF-based sensor demonstrates the good selectivity against the potential interferences and shows high practicability by glucose sensing in human urine and serum samples.
Extended Evaluation of Viral Diversity in Lake Baikal through Metagenomics
Authors: Butina Tatyana V. , Bukin Yurij S. , Petrushin Ivan S. , Tupikin Alexey E. , Kabilov Marsel R. , Belikov Sergey I.
Published: April 2021

Lake Baikal is a unique oligotrophic freshwater lake with unusually cold conditions and amazing biological diversity. Studies of the lake’s viral communities have begun recently, and their full diversity is not elucidated yet. Here, we performed DNA viral metagenomic analysis on integral samples from four different deep-water and shallow stations of the southern and central basins of the lake. There was a strict distinction of viral communities in areas with different environmental conditions. Comparative analysis with other freshwater lakes revealed the highest similarity of Baikal viromes with those of the Asian lakes Soyang and Biwa. Analysis of new data, together with previously published data allowed us to get a deeper insight into the diversity and functional potential of Baikal viruses; however, the true diversity of Baikal viruses in the lake ecosystem remains still unknown. The new metaviromic data will be useful for future studies of viral composition, distribution, and the dynamics associated with global climatic and anthropogenic impacts on this ecosystem.
Two-Step Solvent Extraction of Radioactive Elements and Rare Earths from Estonian Phosphorite Ore Using Nitrated Aliquat 336 and Bis(2-ethylhexyl) Phosphate
Authors: Jürjo Silvester , Siinor Liis , Siimenson Carolin , Paiste Päärn , Lust Enn
Published: April 2021

Estonian phosphorite ore contains trace amounts of rare earth elements (REEs), many other d-metals, and some radioactive elements. Rare earth elements, Mo, V, etc. might be economically exploitable, while some radioactive and toxic elements should be removed before any other downstream processing for environmental and nutritional safety reasons. All untreated hazardous elements remain in landfilled waste in much higher concentration than they occur naturally. To resolve this problem U, Th, and Tl were removed from phosphorite ore at first using liquid extraction. In the next step, REE were isolated from raffinate. Nitrated Aliquat 336 (A336[NO3]) and Bis(2-ethylhexyl) Phosphate (D2EHPA) were used in liquid extraction for comparison. An improved method for exclusive separation of radioactive elements and REEs from phosphorite ore in 2-steps has been developed, exploiting liquid extraction at different pH values.
Synthesis, Characterization and Biological Evaluation of New 3,5-Disubstituted-Pyrazoline Derivatives as Potential Anti-Mycobacterium tuberculosis H37Ra Compounds
Authors: Wong Kok Tong , Osman Hasnah , Parumasivam Thaigarajan , Supratman Unang , Che Omar Mohammad Tasyriq , Azmi Mohamad Nurul
Published: April 2021

A total of fourteen pyrazoline derivatives were synthesized through cyclo-condensation reactions by chalcone derivatives with different types of semicarbazide. These compounds were characterized by IR, 1D-NMR (1H, 13C and Distortionless Enhancement by Polarization Transfer - DEPT-135) and 2D-NMR (COSY, HSQC and HMBC) as well as mass spectroscopy analysis (HRMS). The synthesized compounds were tested for their antituberculosis activity against Mycobacterium tuberculosis H37Ra in vitro. Based on this activity, compound 4a showed the most potent inhibitory activity, with a minimum inhibitory concentration (MIC) value of 17 μM. In addition, six other synthesized compounds, 5a and 5c–5g, exhibited moderate activity, with MIC ranges between 60 μM to 140 μM. Compound 4a showed good bactericidal activity with a minimum bactericidal concentration (MBC) value of 34 μM against Mycobacterium tuberculosis H37Ra. Molecular docking studies for compound 4a on alpha-sterol demethylase was done to understand and explore ligand–receptor interactions, and to hypothesize potential refinements for the compound.
Boosting the Tunable Microwave Scattering Signature of Sensing Array Platforms Consisting of Amorphous Ferromagnetic Fe2.25Co72.75Si10B15 Microwires and Its Amplification by Intercalating Cu Microwires
Authors: Archilla Diego , López-Sánchez Jesús , Hernando Antonio , Navarro Elena , Marín Pilar
Published: April 2021

The following work addresses new configurations of sensing array platforms that are composed of Co-based amorphous ferromagnetic microwires (MWs) to obtain an enhanced modulation of the microwave scattering effects through the application of low strength DC or AC magnetic fields. An amorphous MW is an ultrasoft ferromagnetic material (coercivity ~0.2 Oe) with a circumferential magnetic anisotropy that provides a high surface sensitivity when it is subjected to an external magnetic field. Firstly, microwave scattering experiments are performed as a function of the length and number of MWs placed parallel to each other forming an array. Subsequently, three array configurations are designed, achieving high S21 scattering coefficients up to about −50 dB. The influence of DC and AC magnetic fields on S21 has been analyzed in frequency and time domains representation, respectively. In addition, the MWs sensing array has been overlapped by polymeric surfaces and the variations of their micrometric thicknesses also cause strong changes in the S21 amplitude with displacements in the frequency that are associated to the maximum scattering behavior. Finally, a new concept for amplifying microwave scattering is provided by intercalating Cu MWs into the linear Co-based arrays. The designed mixed system that is composed by Co-based and Cu MWs exhibits a higher S21 coefficient when compared to a single Co-based MW system because of higher electrical conductivity of Cu. However, the ability to modulate the resulting electromagnetic scattering is conferred by the giant magneto-impedance (GMI) effects coming from properties of the ultrasoft amorphous MWs. The mixed array platform covers a wide range of sensor applications, demonstrating the feasibility of tuning the S21 amplitude over a wide scattering range by applying AC or DC magnetic fields and tuning the resonant frequency position according to the polymeric slab thickness.
Flame Spray Pyrolysis Co3O4/CoO as Highly-Efficient Nanocatalyst for Oxygen Reduction Reaction
Authors: Belles Loukas , Moularas Constantinos , Smykała Szymon , Deligiannakis Yiannis
Published: April 2021

The oxygen reduction reaction (ORR) is the rate-limiting reaction in the cathode side of fuel cells. In the quest for alternatives to Pt-electrodes as cathodes in ORR, appropriate transition metal oxide-based electrocatalysts are needed. In the present work, we have synthesized Co3O4 and CoO/Co3O4 nanostructures using flame spray pyrolysis (FSP), as electrocatalysts for ORR in acidic and alkaline media. A detailed study of the effect of (Co-oxide)/Pt ratio on ORR efficiency shows that the present FSP-made Co-oxides are able to perform ORR at very low-Pt loading, 0.4% of total metal content. In acid medium, an electrode with (5.2% Pt + 4.8% Co3O4), achieved the highest ORR performance (Jmax = 8.31 mA/cm2, E1/2 = 0.66 V). In alkaline medium, superior performance and stability have been achieved by an electrode with (0.4%Pt + 9.6% (CoO/Co3O4)) with ORR activity (Jmax = 3.5 mA/cm2, E1/2 = 0.08 V). Using XRD, XPS, Raman and TEM data, we discuss the structural and electronic aspects of the FSP-made Co-oxide catalysts in relation to the ORR performance. Cyclic voltammetry data indicate that the ORR process involves active sites associated with Co3+ cations at the cobalt oxide surface. Technology-wise, the present work demonstrates that the developed FSP-protocols, constitutes a novel scalable process for production of co-oxides appropriate for oxygen reduction reaction electrodes.
An Italian Survey on Dietary Habits and Changes during the COVID-19 Lockdown
Authors: Izzo Luana , Santonastaso Antonio , Cotticelli Gaetano , Federico Alessandro , Pacifico Severina , Castaldo Luigi , Colao Annamaria , Ritieni Alberto
Published: April 2021

The World Health Organization has declared the coronavirus outbreak a Public Health Emergency of International Concern; the outbreak has led to lockdowns in several parts of the world, and sudden changes in people’s lifestyles. This study explores the impact of the first coronavirus disease 2019 (COVID-19) pandemic period on dietary habits, lifestyle changes, and adherence to the Mediterranean diet among the Italian population, through an online questionnaire, conducted from April to May 2020, involving 1519 participants. The 14-point Mediterranean Diet Adherence Screener (MEDAS) highlighted a medium Mediterranean diet adherence in 73.5% of responders, which principally included the younger population, aged 18–30 years (p < 0.05). In regards to changes in eating habits, 33.5% of responders declared an influence of the pandemic period on nutritional practice. A decrease in alcohol consumption was reported by 81% of responders, while an increase in frozen food consumption was reported by 81.3% of responders. In addition, 58.8% reported positive weight modification (40.8%, +1–3 kg); physical activity reduction was reported for 70.5% of responders. Our study contributes toward amplifying the investigation on the dietary habits and changes of the Italian population during the COVID-19 lockdown, although the pandemic is ongoing. Similar studies should be performed around the world to understand how the emergency has impacted people’s habits.
Feasibility, Acceptability, and Preliminary Validity of Self-Report Dietary Assessment in Adults with Multiple Sclerosis: Comparison with Doubly Labeled Water Measured Total Energy Expenditure
Authors: Silveira Stephanie L. , Jeng Brenda , Gower Barbara A. , Motl Robert W.
Published: April 2021

Background: Diet is a modifiable behavior of interest in multiple sclerosis (MS); however, measures of diet in persons with MS have not been vetted for feasibility, acceptability, and validity. Methods: This cross-sectional study examined the Automated Self-Administered 24-H (ASA24) Dietary Assessment Tool in 30 persons with MS and 15 healthy control (HC) participants. Participants were prompted to complete six ASA24 recalls and undergo a standard doubly labeled water (DLW) protocol. Acceptability of ASA24 was assessed using an online questionnaire. Total energy expenditure (TEE) from DLW was compared with ASA24-reported energy intake for assessing validity. Results: All participants completed four or more ASA24 recalls, indicating feasibility of ASA24. Regarding acceptability, the hardest part of completing the ASA24 was remembering everything eaten the previous day. Pearson correlation coefficients between DLW TEE and ASA24 kcal/day were not significant among HC (r = 0.40; p = 0.14) or MS (r = 0.26; p = 0.16) participants. The absolute mean error between DLW TEE and ASA24 among HC participants was 694.96 ± 506.25 mean kcal/day and among MS participants was 585.37 ± 529.02 mean kcal/day; this represents a mean difference of 30 and 25%, respectively. Conclusion: This study established the feasibility and acceptability of ASA24 in persons with MS and provides a foundation regarding the need for further validation research examining appropriate outcomes for supporting dietary interventions.
The First Report of a Methicillin-Resistant Staphylococcus aureus Isolate Harboring Type IV SCCmec in Thailand
Authors: Santimaleeworagun Wichai , Preechachuawong Praewdow , Samret Wandee , Jitwasinkul Tossawan
Published: April 2021

Methicillin-resistant Staphylococcus aureus (MRSA) is mostly found in Thailand in the hospital as a nosocomial pathogen. This study aimed to report the genetic characterization of a clinical community-acquired MRSA (CA-MRSA) isolate collected from hospitalized patients in Thailand. Among 26 MRSA isolates, S. aureus no. S17 preliminarily displayed the presence of a staphylococcal cassette chromosome mec (SCCmec) type IV pattern. The bacterial genomic DNA was subjected to whole-genome sequencing. Panton–Valentine leukocidin (PVL) production, virulence toxins, and antibiotic resistance genes were identified, and multi-locus sequence typing (MLST) and spa typing were performed. The strain was matched by sequence to MLST type 2885 and spa type t13880. This strain carried type IV SCCmec with no PVL production. Five acquired antimicrobial resistance genes, namely blaZ, mecA, Inu(A), tet(K), and dfrG conferring resistance to β-lactams, lincosamides, tetracycline, and trimethoprim, were identified. The detected toxins were exfoliative toxin A, gamma-hemolysin, leukocidin D, and leukocidin E. Moreover, there were differences in seven regions in CR-MRSA no. S17 compared to CA-MRSA type 300. In summary, we have reported the ST2885-SCCmec IV CA-MRSA clinical strain in Thailand for the first time, highlighting the problem of methicillin resistance in community settings and the consideration in choosing appropriate antibiotic therapy.