bluuebunny/crossref_metadata_2025 huggingface dataset:
Level of Financial Performance of Selected Construction Companies in South Africa
Authors: Omopariola Emmanuel Dele , Windapo Abimbola , Edwards David John , El-Gohary Hatem
Published: October 2021

Purpose—There is no consensus on the indicators that assess a construction company’s financial performance projects undertaken. There is also a dearth of concepts on the financial performance indicators for construction companies in South Africa and indeed, the wider continent of Africa. This paper proposes novel financial performance indicators for assessing construction organizations and tests these on selected construction companies in the South African construction industry. Design/methodology/approach—This research employed a pragmatic approach. Contractors with financial credibility and capacity of ≥R 40 million, annual turnover of ≥R 20 million, and available capital of ≥R 40 million were purposively selected for this study. Parameters such as total revenue, direct cost of work, total indirect cost and total income were elicited from the sample contractors to assess their financial performance. The assessment was undertaken using formulas that were formulated based on the descriptions provided under the research methodology. Further analysis was conducted using post hoc Tukey’s honest significant difference (HSD). Findings—The study finds that construction companies with a strong structure, multiple areas of specialization, creative and efficient staff members, and access to funding, have a greater chance of experiencing higher: income; positive leverage; positive liquidity; and positive cash flow. Moreover, companies with specialization in civil engineering construction and project management skills experienced higher positive liquidity and profitability. Originality/value—This research is unique through its investigation and formulation of indicators for assessing the financial performance of construction companies. This research is consequently representing the first attempt to analyze financial data using the approaches prescribed and adopted.
Contemporary Processes of Concentration and Specialization of Industrial Activity in Post-Socialist States as Illustrated by the Case of Wrocław and Its Suburbs (Poland)
Authors: Sikorski Dominik , Brezdeń Paweł
Published: October 2021

This paper explores the issues of contemporary spatial differentiation in the process of industry concentration and the accompanying specialization according to the intensity of research and development in urban agglomerations, as exemplified by Wrocław and its suburbs. The aim of the study was to assess the degree and directions of advancement of these processes and to identify spatial patterns in the location and relocation of industry operators in the analyzed area. The industrial location was analyzed on the basis of industry operators registered in section C (industrial processing) according to the Polish Classification of Activities (PKA) in city districts in 2008 and 2016. The industry’s spatial structures were presented using the classification of industrial processing according to R&D intensity broken down into high-, medium-high-, medium-low-, and low-tech industry sectors. Quantitative methods were used to analyze and identify the degree of spatial concentration and specialization of the industry. The underlying analytical statistics included relative indicators, such as the location quotient (LQ), Florence’s location quotient, or the Krugman Specialization Index, as well as analyses of market structures (Herfindahl–Hirschman index or discrete index). The findings of this research revealed quite significant changes taking place in the internal spatial structure of Wrocław and its immediate vicinity in terms of the industry concentration and specialization. This phenomenon was much more dynamic and turbulent in the post-socialist countries than in the cities of Western Europe. Likewise, Wrocław and its suburban zone are characterized by a significant diversification and intensity of the processes subject to this analysis. These processes proved to be complex and selective.
Hydrodynamic Bearing Structural Design of Blood Pump Based on Axial Passive Suspension Stability Analysis of Magnetic–Hydrodynamic Hybrid Suspension System
Authors: Shen Peng , Wang Yiwen , Chen Yun , Fu Pengqiang , Zhou Lijie , Liu Lijia
Published: October 2021

Rotor suspension stability is one of the important performance indexes of a blood pump and the basis of determining whether the blood pump can be used in a clinic. Compared with the traditional magnetic suspension system, a single-winding, bearingless motor has the advantages of a compact structure, simple control system and low power consumption. In this pursuit, the present study aimed to envisage and design the magnetic suspension system coupled with a single-winding bearingless motor and permanent magnet bearings, establish the theoretical models of axial force and electromagnetic torque, and calculate the stiffness of the magnetic suspension system at the equilibrium point. Addressing the problem of the negative axial stiffness of the magnetic suspension system being negative, which leads to the instability of the suspension rotor, the hydrodynamic bearing structure was proposed and designed, and the critical stiffness to realize the stable suspension of the rotor was obtained based on the stability criterion of the rotor dynamics model. The optimal structural parameters of the hydrodynamic bearing are selected by integrating various factors based on the solution of the Reynolds equation and a stiffness analysis. Furthermore, the vibration experiment results proved that the blood pump rotor exhibited a good suspension stability, and the maximum offset under the impact external fluid was no more than 2 μm.
Topic-Based Document-Level Sentiment Analysis Using Contextual Cues
Authors: Truică Ciprian-Octavian , Apostol Elena-Simona , Șerban Maria-Luiza , Paschke Adrian
Published: October 2021

Document-level Sentiment Analysis is a complex task that implies the analysis of large textual content that can incorporate multiple contradictory polarities at the phrase and word levels. Most of the current approaches either represent textual data using pre-trained word embeddings without considering the local context that can be extracted from the dataset, or they detect the overall topic polarity without considering both the local and global context. In this paper, we propose a novel document-topic embedding model, DocTopic2Vec, for document-level polarity detection in large texts by employing general and specific contextual cues obtained through the use of document embeddings (Doc2Vec) and Topic Modeling. In our approach, (1) we use a large dataset with game reviews to create different word embeddings by applying Word2Vec, FastText, and GloVe, (2) we create Doc2Vecs enriched with the local context given by the word embeddings for each review, (3) we construct topic embeddings Topic2Vec using three Topic Modeling algorithms, i.e., LDA, NMF, and LSI, to enhance the global context of the Sentiment Analysis task, (4) for each document and its dominant topic, we build the new DocTopic2Vec by concatenating the Doc2Vec with the Topic2Vec created with the same word embedding. We also design six new Convolutional-based (Bidirectional) Recurrent Deep Neural Network Architectures that show promising results for this task. The proposed DocTopic2Vecs are used to benchmark multiple Machine and Deep Learning models, i.e., a Logistic Regression model, used as a baseline, and 18 Deep Neural Networks Architectures. The experimental results show that the new embedding and the new Deep Neural Network Architectures achieve better results than the baseline, i.e., Logistic Regression and Doc2Vec.
An Efficient Discrete Model to Approximate the Solutions of a Nonlinear Double-Fractional Two-Component Gross–Pitaevskii-Type System
Authors: Macías-Díaz Jorge E. , Reguera Nuria , Serna-Reyes Adán J.
Published: October 2021

In this work, we introduce and theoretically analyze a relatively simple numerical algorithm to solve a double-fractional condensate model. The mathematical system is a generalization of the famous Gross–Pitaevskii equation, which is a model consisting of two nonlinear complex-valued diffusive differential equations. The continuous model studied in this manuscript is a multidimensional system that includes Riesz-type spatial fractional derivatives. We prove here the relevant features of the numerical algorithm, and illustrative simulations will be shown to verify the quadratic order of convergence in both the space and time variables.
Cytoprotective Peptides from Blue Mussel Protein Hydrolysates: Identification and Mechanism Investigation in Human Umbilical Vein Endothelial Cells Injury
Authors: Suryaningtyas Indyaswan Tegar , Ahn Chang-Bum , Je Jae-Young
Published: October 2021

Cardiovascular disease represents a leading cause of mortality and is often characterized by the emergence of endothelial dysfunction (ED), a physiologic condition that takes place in the early progress of atherosclerosis. In this study, two cytoprotective peptides derived from blue mussel chymotrypsin hydrolysates with the sequence of EPTF and FTVN were purified and identified. Molecular mechanisms underlying the cytoprotective effects against oxidative stress which lead to human umbilical vein endothelial cells (HUVEC) injury were investigated. The results showed that pretreatment of EPTF, FTVN and their combination (1:1) in 0.1 mg/mL significantly reduced HUVEC death due to H2O2 exposure. The cytoprotective mechanism of these peptides involves an improvement in the cellular antioxidant defense system, as indicated by the suppression of the intracellular ROS generation through upregulation of the cytoprotective enzyme heme oxygenase-1. In addition, H2O2 exposure triggers HUVEC damage through the apoptosis process, as evidenced by increased cytochrome C release, Bax protein expression, and the elevated amount of activated caspase-3, however in HUVEC pretreated with peptides and their combination, the presence of those apoptotic stimuli was significantly decreased. Each peptide showed similar cytoprotective effect but no synergistic effect. Taken together, these peptides may be especially important in protecting against oxidative stress-mediated ED.
Investigation of Factors Influencing the Autoclave Tests Results of Internal Anticorrosive Polymer Coatings
Authors: Kovalev Mark , Alekseeva Ekaterina , Shaposhnikov Nikita , Lyashenko Daniil , Tokarev Vasiliy
Published: October 2021

Polymer coatings are one of the most common methods for protecting metal structures from corrosion damage. For example, in the oil and gas industry, polymer coatings are used to protect the inner surfaces of oilfield pipelines. Forecasting the service life of the coating is an unsolved problem. Existing test methods allow to assess the quality of coating application and compliance with the declared properties, for example, resistance at a certain temperature, but do not allow to understand the expected service life or degradation dynamics. One solution to this problem may be the development of existing methods of autoclave testing of coatings with the addition of more criteria for assessing degradation. This paper considers the methodological features of autoclave testing with rapid pressure relief. The decompression autoclave test was considered from the point of view of the principles of its conduct and evaluation of test results. The tests were carried out in environments containing hydrogen sulfide and carbon dioxide. The main object of the tests was anticorrosive polymer powder coatings applied in industrial conditions. The work assessed the influence of the following factors on the test result: pressure relief time, test cycle, and coating quality. Attention was also paid to the evaluation methods; aside from the adhesion assessment, optical microscopy and the evaluation of the microhardness of coatings were used. As a result of the work carried out, it was shown that the pressure relief rate within 5 s affects the test results. An increase in micropores and a drop in the microhardness of coatings after cyclic autoclave tests were also shown. The method of assessing the degradation of coatings using microhardness also showed the convergence of the results with the traditional method of assessing adhesion. The results of the work can be used to modify the autoclave testing method and transition to resource forecasting.
Flagella, Type I Fimbriae and Curli of Uropathogenic Escherichia coli Promote the Release of Proinflammatory Cytokines in a Coculture System
Authors: Vega-Hernández Rubí , Ochoa Sara A. , Valle-Rios Ricardo , Jaimes-Ortega Gustavo A. , Arellano-Galindo José , Aparicio-Ozores Gerardo , Ibarra José Antonio , Hernández-Castro Rigoberto , Cruz-Córdova Ariadnna , Xicohtencatl-Cortes Juan
Published: October 2021

Background. Urinary tract infections (UTIs) are a public health problem in Mexico, and uropathogenic Escherichia coli (UPEC) is one of the main etiological agents. Flagella, type I fimbriae, and curli promote the ability of these bacteria to successfully colonize its host. Aim. This study aimed to determine whether flagella-, type I fimbriae-, and curli-expressing UPEC induces the release of proinflammatory cytokines in an established coculture system. Methods. The fliC, fimH, and csgA genes by UPEC strain were disrupted by allelic replacement. Flagella, type I fimbriae, and curli were visualized by transmission electron microscopy (TEM). HTB-5 (upper chamber) and HMC-1 (lower chamber) cells cocultured in Transwell® plates were infected with these UPEC strains and purified proteins. There was adherence to HTB-5 cells treated with different UPEC strains and they were quantified as colony-forming units (CFU)/mL. Results. High concentrations of IL-6 and IL-8 were induced by the FimH and FliC proteins; however, these cytokines were detected in low concentrations in presence of CsgA. Compared with UPEC CFT073, CFT073ΔfimH, CFT073ΔfimHΔfliC, and CFT073ΔcsgAΔfimH strains significantly reduced the adherence to HTB-5 cells. Conclusion. The FimH and FliC proteins are involved in IL-6 and IL-8 release in a coculture model of HTB-5 and HMC-1 cells.
Nontuberculous Mycobacteria Prevalence in Bats’ Guano from Caves and Attics of Buildings Studied by Culture and qPCR Examinations
Authors: Pavlik Ivo , Ulmann Vit , Modra Helena , Gersl Milan , Rantova Barbora , Zukal Jan , Zukalova Katerina , Konecny Ondrej , Kana Vlastislav , Kubalek Pavel , Babak Vladimir , Weston Ross Tim
Published: October 2021

A total of 281 guano samples were collected from caves (N = 181) in eight European countries (Bulgaria, Czech Republic, France, Hungary, Italy, Romania, Slovakia and Slovenia) and attics in the Czech R. (N = 100). The correlation of detection of mycobacteria between Ziehl–Neelsen (ZN) microscopy and culture examination and qPCR was strong. ZN microscopy was positive in guano from caves (58.6%) more than double than positivity in guano from attics (21.0%; p < 0.01). From 89 mycobacterial isolates (73 isolates from cave guano and 16 isolates from attics’ guano), 68 (76.4%) isolates of 19 sp., ssp. and complex were identified as members of three Groups (M. fortuitum, M.chelonae, and M. mucogenicum) and four complexes (M. avium, M. terrae, M.vaccae, and M.smegmatis). A total of 20 isolates (22.5%) belonged to risk group 1 (environmental saprophytes), 48 isolates (53.9%) belonged to risk group 2 (potential pathogens), and none of the isolates belonged to risk group 3 (obligatory pathogens). When comparing bat guano collected from caves and attics, differences (p < 0.01; Mann–Whitney test) were observed for the electrical conductivity, total carbon, total organic, and total inorganic carbon. No difference (p > 0.05; Mann–Whitney test) was found for pH and oxidation-reduction potential parameters.
Bacterial Community and Anti-Cerebrovascular Disease-Related Bacillus Species Isolated from Traditionally Made Kochujang from Different Provinces of Korea
Authors: Ha Gwangsu , Yang Hee-Jong , Ryu Myeong-Seon , Jeong Su-Ji , Jeong Do-Youn , Park Sunmin
Published: October 2021

Traditionally made Kochujang (TMK) is a long-term fermented soybean and rice mixture with red pepper and salts. The ambient bacteria in rice straw and nutrient components of Kochujang influence the bacteria community. We aimed to investigate the bacterial composition and quality of TMK from different provinces of Korea: Chungcheung (CC), Jeolla (JL), Kyungsang (KS), and GeongGee plus Kangwon (GK) provinces, and Jeju island (JJ). Furthermore, Bacillus spp. isolated from TMK were studied to have anti-cerebrovascular disease activity and probiotic properties. Seventy-three TMK samples from different regions were collected to assess the biogenic amine contents, bacteria composition using next-generation methods, and bacterial functions using Picrust2. Bacillus spp. was isolated from the collected TMK, and their antioxidant, fibrinolytic, and angiotensin I conversion enzyme (ACE) inhibitory activities and probiotic properties were examined. KS TMK had lower sodium contents than the other TMK. There were no significant differences in histamine and tyramine contents among the TMK samples in different provinces. The predominant bacteria in TMK was Bacillus spp., but KS included much less Bacillus spp. and higher Enterococcus and Staphylococcus than the other TMK. Gene expression related to lipopolysaccharide biosynthesis was higher in KS TMK than the other TMK in Picrust2. The predominant Bacillus spp. isolated from TMK was B. subtilis and B. velezensis. B. subtilis SRCM117233, SRCM117245, and SRCM117253 had antioxidant activity, whereas B. subtilis had higher fibrinolytic activity than other Bacillus spp. Only B. velezensis SRCM117254, SRCM117311, SRCM117314, and SRCM117318 had over 10% ACE inhibitory activity. In conclusion, KS had less Bacillus related to lower sodium contents than the other TMK. The specific strains of B. subtilis and B. velezensis had antioxidant, fibrinolytic, and ACE inhibitory activity, and they can be used as a starter culture to produce better quality controlled Kochujang with anti-cerebrovascular disease activities.
Highly Sensitive, Selective, Flexible and Scalable Room-Temperature NO2 Gas Sensor Based on Hollow SnO2/ZnO Nanofibers
Authors: Guo Jiahui , Li Weiwei , Zhao Xuanliang , Hu Haowen , Wang Min , Luo Yi , Xie Dan , Zhang Yingjiu , Zhu Hongwei
Published: October 2021

Semiconducting metal oxides can detect low concentrations of NO2 and other toxic gases, which have been widely investigated in the field of gas sensors. However, most studies on the gas sensing properties of these materials are carried out at high temperatures. In this work, Hollow SnO2 nanofibers were successfully synthesized by electrospinning and calcination, followed by surface modification using ZnO to improve the sensitivity of the SnO2 nanofibers sensor to NO2 gas. The gas sensing behavior of SnO2/ZnO sensors was then investigated at room temperature (~20 °C). The results showed that SnO2/ZnO nanocomposites exhibited high sensitivity and selectivity to 0.5 ppm of NO2 gas with a response value of 336%, which was much higher than that of pure SnO2 (13%). In addition to the increase in the specific surface area of SnO2/ZnO-3 compared with pure SnO2, it also had a positive impact on the detection sensitivity. This increase was attributed to the heterojunction effect and the selective NO2 physisorption sensing mechanism of SnO2/ZnO nanocomposites. In addition, patterned electrodes of silver paste were printed on different flexible substrates, such as paper, polyethylene terephthalate and polydimethylsiloxane using a facile screen-printing process. Silver electrodes were integrated with SnO2/ZnO into a flexible wearable sensor array, which could detect 0.1 ppm NO2 gas after 10,000 bending cycles. The findings of this study therefore open a general approach for the fabrication of flexible devices for gas detection applications.
Advances in [18F]Trifluoromethylation Chemistry for PET Imaging
Authors: Francis Felix , Wuest Frank
Published: October 2021

Positron emission tomography (PET) is a preclinical and clinical imaging technique extensively used to study and visualize biological and physiological processes in vivo. Fluorine-18 (18F) is the most frequently used positron emitter for PET imaging due to its convenient 109.8 min half-life, high yield production on small biomedical cyclotrons, and well-established radiofluorination chemistry. The presence of fluorine atoms in many drugs opens new possibilities for developing radioligands labelled with fluorine-18. The trifluoromethyl group (CF3) represents a versatile structural motif in medicinal and pharmaceutical chemistry to design and synthesize drug molecules with favourable pharmacological properties. This fact also makes CF3 groups an exciting synthesis target from a PET tracer discovery perspective. Early attempts to synthesize [18F]CF3-containing radiotracers were mainly hampered by low radiochemical yields and additional challenges such as low radiochemical purity and molar activity. However, recent innovations in [18F]trifluoromethylation chemistry have significantly expanded the chemical toolbox to synthesize fluorine-18-labelled radiotracers. This review presents the development of significant [18F]trifluoromethylation chemistry strategies to apply [18F]CF3-containing radiotracers in preclinical and clinical PET imaging studies. The continuous growth of PET as a crucial functional imaging technique in biomedical and clinical research and the increasing number of CF3-containing drugs will be the primary drivers for developing novel [18F]trifluoromethylation chemistry strategies in the future.
Vibrational Study on Structure and Bioactivity of Protein Fibers Grafted with Phosphorylated Methacrylates
Authors: Di Foggia Michele , Tsukada Masuhiro , Taddei Paola
Published: October 2021

In the last decades, silk fibroin and wool keratin have been considered functional materials for biomedical applications. In this study, fabrics containing silk fibers from Bombyx mori and Tussah silk fibers from Antheraea pernyi, as well as wool keratin fabrics, were grafted with phosmer CL and phosmer M (commercial names, i.e., methacrylate monomers containing phosphate groups in the molecular side chain) with different weight gains. Both phosmers were recently proposed as flame retarding agents, and their chemical composition suggested a possible application in bone tissue engineering. IR and Raman spectroscopy were used to disclose the possible structural changes induced by grafting and identify the most reactive amino acids towards the phosmers. The same techniques were used to investigate the nucleation of a calcium phosphate phase on the surface of the samples (i.e., bioactivity) after ageing in simulated body fluid (SBF). The phosmers were found to polymerize onto the biopolymers efficiently, and tyrosine and serine underwent phosphorylation (monitored through the strengthening of the Raman band at 1600 cm−1 and the weakening of the Raman band at 1400 cm−1, respectively). In grafted wool keratin, cysteic acid and other oxidation products of disulphide bridges were detected together with sulphated residues. Only slight conformational changes were observed upon grafting, generally towards an enrichment in ordered domains, suggesting that the amorphous regions were more prone to react (and, sometimes, degrade). All samples were shown to be bioactive, with a weight gain of up to 8%. The most bioactive samples contained the highest phosmers amounts, i.e., the highest amounts of phosphate nucleating sites. The sulphate/sulphonate groups present in grafted wool samples appeared to increase bioactivity, as shown by the five-fold increase of the IR phosphate band at 1040 cm−1.
Immune Response of Senegalese Sole against Betanodavirus Mutants with Modified Virulence
Authors: Gémez-Mata Juan , Souto Sandra , Bandín Isabel , Alonso María , Borrego Juan , Labella Alejandro , García-Rosado Esther
Published: October 2021

Nervous necrosis virus (NNV), genus Betanodavirus, the etiological agent of the viral encephalopathy and retinopathy (VER), presents a genome with two positive-sense single-stranded RNA segments. Striped jack nervous necrosis virus (SJNNV) and red-spotted grouper nervous necrosis virus (RGNNV), together with reassortants RGNNV/SJNNV, are the betanodaviruses predominantly isolated in Southern Europe. An RGNNV/SJNNV reassortant isolated from Senegalese sole (wt160) causes high mortalities in this fish species. This virus presents differences in the sequence of the 3’ non-coding region (NCR) of both segments compared to RGNNV and SJNNV reference strains. Previously, it has been reported that the reversion of two of these differences (nucleotides 1408 and 1412) in the RNA2 3’NCR to the SJNNV-type (recombinant r1408-1412) resulted in a decrease in sole mortality. In the present study, we have applied an OpenArray® to analyse the involvement of sole immune response in the virulence of several recombinants: the r1408-1412 and two recombinants, developed in the present study, harbouring mutations at positions 3073 and 3093 of RNA1 3’NCR to revert them to RGNNV-type. According to the correlation values and to the number of expressed genes, the infection with the RNA2-mutant provoked the most different immune response compared to the immune response triggered after the infection with the rest of the viruses, and the exclusive and high upregulation of genes related to the complement system. The infection with the RNA1-mutants also provoked a decrease in mortality and their replication was delayed at least 24 h compared to the wt160 replication, which could provoke the lag observed in the immune response. Furthermore, the infection with the RNA1-mutants provoked the exclusive expression of pkr and the downregulation of il17rc.
Efficacy of Chemical and Biological Stump Treatments for the Control of Heterobasidion occidentale Infection of California Abies concolor
Authors: Poloni Adrian L. , Garbelotto Matteo , Lee Christopher A. , Cobb Richard C.
Published: October 2021

We conducted an experimental evaluation of treatments to limit Heterobasidion occidentale infection of white fir (Abies concolor) stumps and wounds in California mixed conifer forests. We tested the efficacy of urea, borate, and a mixture of two locally collected Phlebiopsis gigantea strains in preventing pathogen colonization of fir stumps and separately, urea and borate as infection controls on experimental stem wounds. These were paired with a laboratory test on ~100 g wood blocks with and without a one-week delay between inoculation and treatment. Urea, borates, and Phlebiopsis treatments all significantly reduced the stump surface area that was colonized by H. occidentale at 84%, 91%, and 68%, respectively, relative to the controls. However, only the borate treatments significantly lowered the number of stumps that were infected by the pathogen. The laboratory study matched the patterns that were found in the stump experiment with a reduced area of colonization for urea, borates, or P. gigantea treatments relative to the controls; delaying the treatment did not affect efficacy. The field wound experiment did not result in any Heterobasidion colonization, even in positive control treatments, rendering the experiment uninformative. Our study suggests treatments that are known to limit Heterobasidion establishment on pine or spruce stumps elsewhere in the world may also be effective on true firs in California.
The Ethics of Plant Flourishing and Agricultural Ethics: Theoretical Distinctions and Concrete Recommendations in Light of the Environmental Crisis
Authors: Hiernaux Quentin
Published: October 2021

Many activities towards plants are directly related to environmental crisis issues. However, our actions towards plants are little theorized in philosophy and ethics. After a brief presentation of the history, state of the art, and current issues of plant ethics, I critically illustrate how the theoretical threads of current ethics should be clarified, and, more importantly, contextualised, to promote the application of concrete measures. Particular attention is paid to the ethics of plant flourishing as applied to different fields and types of plants. The treatment of wild and ornamental plants is, thus, explicitly distinguished from that of improved agricultural varieties, themselves distinguishable according to modes of cultivation. I thus propose and discuss several recommendations and concrete courses of action to promote an ethics of plants, while pointing out its limitations.
Spatial Beam Self-Cleaning in Bi-Tapered Multimode Fibers
Authors: Lin Xiao-Jun , Gao Yu-Xin , Long Jin-Gan , Wu Jia-Wen , Li Xiang-Yue , Hong Wei-Yi , Cui Hu , Luo Zhi-Chao , Xu Wen-Cheng , Luo Ai-Ping
Published: October 2021

We report the spatial beam self-cleaning in bi-tapered conventional multimode fibers (MMFs) with different tapered lengths. Through the introduction of the bi-tapered structure in MMFs, the input beam with poor beam quality from a high-power fiber laser can be converted to a centered, bell-shaped beam in a short length, due to the strengthened nonlinear modes coupling. It is found that the bi-tapered MMF with longer tapered length at the same waist diameter shows better beam self-cleaning effect and larger spectral broadening. The obtained results offer a new method to improve the beam quality of high-power laser at low cost. Furthermore, it may be interesting for manufacturing bi-tapered MMF-based devices to obtain the quasi-fundamental mode beam in spatiotemporal mode-locked fiber lasers.
Morphology and Anatomy of Branch–Branch Junctions in Opuntia ficus-indica and Cylindropuntia bigelovii: A Comparative Study Supported by Mechanical Tissue Quantification
Authors: Mylo Max D. , Hesse Linnea , Masselter Tom , Leupold Jochen , Drozella Kathrin , Speck Thomas , Speck Olga
Published: October 2021

The Opuntioideae include iconic cacti whose lateral branch–branch junctions are intriguing objects from a mechanical viewpoint. We have compared Opuntia ficus-indica, which has stable branch connections, with Cylindropuntia bigelovii, whose side branches abscise under slight mechanical stress. To determine the underlying structures and mechanical characteristics of these stable versus shedding cacti junctions, we conducted magnetic resonance imaging, morphometric and anatomical analyses of the branches and tensile tests of individual tissues. The comparison revealed differences in geometry, shape and material properties as follows: (i) a more pronounced tapering of the cross-sectional area towards the junctions supports the abscission of young branches of C. bigelovii. (ii) Older branches of O. ficus-indica form, initially around the branch–branch junctions, collar-shaped periderm tissue. This secondary coverage mechanically stiffens the dermal tissue, giving a threefold increase in strength and a tenfold increase in the elastic modulus compared with the epidermis. (iii) An approximately 200-fold higher elastic modulus of the vascular bundles of O. ficus-indica is a prerequisite for the stable junction of its young branches. Our results provide, for both biological and engineered materials systems, important insights into the geometric characteristics and mechanical properties of branching joints that are either stable or easily detachable.
Alleviation of Malathion Toxicity Effect by Coffea arabica L. Oil and Olea europaea L. Oil on Lipid Profile: Physiological and In Silico Study
Authors: Al-Asmari Khalid M. , Zeid Isam M. Abu , Altayb Hisham N. , Al-Attar Atef M. , Alomar Mohammed Y.
Published: October 2021

The community health plans commonly use malathion (MAL), an organophosphate pesticide (OP), to eliminate pathogenic insects. The objective of the present research is to evaluate the consequences of Coffea arabica L. oil and Olea europaea L. oil on MAL-intoxicated male rats. Six equal groups of animals were used for conducting this study (n = 10). Animals in group one were designated as control, animals belonging to group two were exposed to MAL in the measure of hundred mg per kg BW (body weight) for forty-nine days (seven weeks), rats in the third and fourth groups were administered with 400 mg/kg BW of Coffea arabica L. and Olea europaea L. oils, respectively, and the same amount of MAL as given to the second group. Groups five and six were administered with the same amount of Coffea arabica L. oil and Olea europaea L. oil as given to group three. Exposure of rats to 100 mg/kg body weight of MAL resulted in statistical alteration of the serum lipid profile. A marked decline was noticed in the severe changes of these blood parameters when MAL-intoxicated rats were treated with Coffea arabica L. oil and Olea europaea L. oil. Two compounds from Coffea arabica L. oil (Chlorogenic acid) and Olea europaea L. oil (Oleuropein) demonstrated good interaction with xanthine oxidase (XO) and 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) enzymes that are associated with cholesterol production. The present study indicated that Coffea arabica L. oil and Olea europaea L. oil could be considered prospective and potential healing agents against metabolic conditions induced by MAL.
Metabolites of Siberian Raspberries: LC-MS Profile, Seasonal Variation, Antioxidant Activity and, Thermal Stability of Rubus matsumuranus Phenolome
Authors: Kashchenko Nina I. , Olennikov Daniil N. , Chirikova Nadezhda K.
Published: October 2021

Rubus matsumuranus H. Lev. & Vaniot, a famous Siberian shrub of the Rosaceae family, is used in the folk medicine of nomads (Buryats, Yakuts, Soyots, and Mongols) as a remedy for the treatment of diseases of the respiratory and hepatobiliary systems. The lack of scientific information on R. matsumuranus leaves contributed to the investigation of the metabolomic profile and biological activity of this plant. In this study, metabolites of R. matsumuranus leaves in three stages (active growth, flowering, and fruiting) were characterised using high-performance liquid chromatography with photodiode array and electrospray ionisation triple quadrupole mass spectrometric detection (HPLC-PDA-ESI-tQ-MS). In total, 63 compounds were identified, including gallic acid derivatives, hydroxycinnamates, catechins, procyanidins, flavonols, and ellagitannins. Lambertianin C (57.11 mg/g of dry weight, DW), miquelianin (39.63 mg/g DW), and kaempferol-3-O-glucuronide (31.18 mg/g DW) were the major compounds in R. matsumuranus leaves. As a result of the HPLC-PDA-based assay to determine the antioxidant activity, it was revealed that lambertianin A, sanguiin H6, lambertianin C, and sanguiin H11 were effective scavengers of free radicals (2,2-diphenyl-1-picrylhydrazyl, DPPH•) and possessed Fe2+-chelating activity. After an investigation of the phenolic content in infusions and decoctions obtained by extraction with water at different temperatures, it was revealed that a hot infusion (80 °C) is a phenolic-rich preparation of R. matsumuranus leaves. Our research suggests that R. matsumuranus leaves are a rich source of phenolic compounds with high antioxidant properties and that this could be a prospective plant for new functional products.
Strategic Planning for Carbon Capture and Storage Implementation in the Electricity Sector of Greece: A TIMES Based Analysis
Authors: Ioakimidis Christos S. , Gerbelova Hana , Bagheri Ali , Koutra Sesil , Koukouzas Nikolaos
Published: October 2021

This paper presents a roadmap performed in 2010 as part of a European project for the modelling of carbon capture and storage technology, and various scenarios with different taxations and permit prices for the CO2 emissions considering the Greek national plans, then the gradual decommissioning of various lignite or other units of electricity power plants. In addition, this study presents a first check, 10 years after its writing, of the current situation of the Greek energy system, regarding the correspondence of the roadmap designed in 2010 to what has been finally executed during this period, including the possibility of other energy sources complimenting or substituting the national strategic energy plans. For this purpose, the integrated MARKAL-EFOM system (TIMES) was employed to model the Greek energy system and evaluate its development over time, until 2040, by analyzing three different scenarios with respect to taxation and permit prices for carbon emissions. The results obtained show that, if this study had been considered and executed by the different stakeholders during that period, then the implementation of CCS in the new licensed power plants from 2010 and onwards could reduce the use of lignite and imported hard coal power production in a much smoother and beneficial way in the next years, and until the present, without compromising any major power plants. This implementation would also make the transition to a lignite free economy in Greece much faster and better, while complimenting the EU regulations and also enhancing the possible greater use of alternative energy sources in the green energy mixture.
Two-Step Intelligent Control for a Green Flexible EV Energy Supply Station Oriented to Dual Carbon Targets
Authors: Shi Shanshan , Fang Chen , Wang Haojing , Li Jianfang , Li Yuekai , Peng Daogang , Zhao Huirong
Published: October 2021

As China proposes to achieve carbon peak by 2030 and carbon neutrality by 2060, as well as the huge pressure on the power grid caused by the load demand of the energy supply stations of electric vehicles (EVs), there is an urgent need to carry out comprehensive energy management and coordinated control for EVs’ energy supply stations. Therefore, this paper proposed a two-step intelligent control method known as ISOM-SAIA to solve the problem of the 24 h control and regulation of green/flexible EV energy supply stations, including four subsystems such as a photovoltaic subsystem, an energy storage subsystem, an EV charging subsystem and an EV battery changing subsystem. The proposed control method has two main innovations and contributions. One is that it reduces the computational burden by dividing the multi-dimensional mixed-integer programming problem of simultaneously optimizing the 24 h operation modes and outputs of four subsystems into two sequential tasks: the classification of data-driven operation modes and the rolling optimization of operational outputs. The other is that proper carbon transaction costs and carbon emission constraints are considered to help save costs and reduce carbon emissions. The simulation analysis conducted in this paper indicates that the proposed two-step intelligent control method can help green/flexible EV energy supply stations to optimally allocate energy flows between four subsystems, effectively respond to peak shaving and valley filling of power grid, save energy costs and reduce carbon emissions.
Joint Power and Channel Optimization of Agricultural Wireless Sensor Networks Based on Hybrid Deep Reinforcement Learning
Authors: Han Xiao , Wu Huarui , Zhu Huaji , Chen Cheng
Published: October 2021

The reduction of maintenance costs in agricultural wireless sensor networks (WSNs) requires reducing energy consumption. At the same time, care should be taken not to affect communication quality and network lifetime. This paper studies a joint optimization algorithm for transmitted power and channel allocation based on deep reinforcement learning. First, an optimization model to measure network reward was established under the constraint of the signal-to-interference plus-noise-ratio (SINR) threshold, which includes continuous power variables and discrete channel variables. Secondly, considering the dynamic changes of agricultural WSNs, the network control is described as a Markov decision process with continuous state and action space. A deep deterministic policy gradient (DDPG) reinforcement learning scheme suitable for mixed variables was designed. This method could obtain a control scheme that maximizes network reward by means of black-box optimization for continuous transmitted power and discrete channel allocation. Experimental results indicated that the studied algorithm has stable convergence. Compared with traditional protocols, it can better control the transmitted power and allocate channels. The joint power and channel optimization provides a reference solution for constructing an energy-balanced network.
Improved CYGNSS Wind Speed Retrieval Using Significant Wave Height Correction
Authors: Pascual Daniel , Clarizia Maria Paola , Ruf Christopher S.
Published: October 2021

This article presents the methodology for an improved estimation of the sea surface wind speed measured by the cyclone global navigation satellite system (CYGNSS) constellation of satellites using significant wave height (SWH) information as external reference data. The methodology consists of a correcting 2D look-up table (LUT) with inputs: (1) the CYGNSS wind speed given by the geophysical model function (GMF); and (2) the collocated reference SWH given by the WW3 model, which is forced by winds from the European Centre for Medium-Range Weather Forecasts (ECMWF) organization. In particular, the analyzed CYGNSS wind speeds are the fully developed seas (FDS) obtained with the GMF 3.0, and the forcing winds are the ECMWF forecast winds. Results show an increase in sensitivity to large winds speeds and an overall reduction in the root mean square difference (RMSD) with respect to the ECMWF winds from 2.05 m/s to 1.74 m/s. The possible influence of the ECWMF winds on the corrected winds (due to their use in the WW3 model) is analyzed by considering the correlation between: (1) the difference between the ECMWF winds and those from another reference; and (2) the difference between the corrected CYGNSS winds and those from the same reference. Results using ASCAT, WindSat, Jason, and AltiKa as references show no significant influence.
Measuring Coastal Absolute Sea-Level Changes Using GNSS Interferometric Reflectometry
Authors: Peng Dongju , Feng Lujia , Larson Kristine M. , Hill Emma M.
Published: October 2021

Rising sea levels pose one of the greatest threats to coastal zones. However, sea-level changes near the coast, particularly absolute sea-level changes, have been less well monitored than those in the open ocean. In this study, we aim to investigate the potential of Global Navigation Satellite Systems Interferometric Reflectometry (GNSS-IR) to measure coastal absolute sea-level changes and tie on-land (coastal GNSS) and offshore (satellite altimetry) observations into the same framework. We choose three coastal GNSS stations, one each in regions of subsidence, uplift and stable vertical land motions, to derive both relative sea levels and sea surface heights (SSH) above the satellite altimetry reference ellipsoid from 2008 to 2020. Our results show that the accuracy of daily mean sea levels from GNSS-IR is <1.5 cm compared with co-located tide-gauge records, and amplitudes of annual cycle and linear trends estimated from GNSS-IR measurements and tide-gauge data agree within uncertainty. We also find that the de-seasoned and de-trended SSH time series from GNSS-IR and collocated satellite altimetry are highly correlated and the estimated annual amplitudes and linear trends statistically agree well, indicating that GNSS-IR has the potential to monitor coastal absolute sea-level changes and provide valuable information for coastal sea-level and climate studies.
Modelling Aboveground Biomass Carbon Stock of the Bohai Rim Coastal Wetlands by Integrating Remote Sensing, Terrain, and Climate Data
Authors: Sun Shaobo , Wang Yafei , Song Zhaoliang , Chen Chu , Zhang Yonggen , Chen Xi , Chen Wei , Yuan Wenping , Wu Xiuchen , Ran Xiangbin , Wang Yidong , Li Qiang , Wu Lele
Published: October 2021

Remotely sensed vegetation indices (VIs) have been widely used to estimate the aboveground biomass (AGB) carbon stock of coastal wetlands by establishing Vis-related linear models. However, these models always have high uncertainties due to the large spatial variation and fragmentation of coastal wetlands. In this paper, an efficient coastal wetland AGB model for the Bohami Rim coastal wetlands was presented based on multiple data sets. The model was developed statistically with 7 independent variables from 23 metrics derived from remote sensing, topography, and climate data. Compared to previous models, it had better performance, with a root mean square error and r value of 188.32 g m−2 and 0.74, respectively. Using the model, we firstly generated a regional coastal wetland AGB map with a 10 m spatial resolution. Based on the AGB map, the AGB carbon stock of the Bohai Rim coastal wetland was 2.11 Tg C in 2019. The study demonstrated that integrating emerging high spatial resolution multi-remote sensing data and several auxiliary metrics can effectively improve VIs-based coastal wetland AGB models. Such models with emerging freely available data sets will allow for the rapid monitoring and better understanding of the special role that “blue carbon” plays in global carbon cycle.
Analysis of Air-Coupled Transducer-Based Elastic Waves Generation in CFRP Plates
Authors: Wandowski Tomasz , Mindykowski Damian , Kudela Pawel , Radzienski Maciej
Published: October 2021

In this paper, the analysis of non-contact elastic waves generation in carbon fiber reinforced-polymer (CFRP) plate was conducted. Full non-contact elastic waves generation and sensing methods were also analyzed. Elastic waves generation was based on an air-coupled transducer (ACT) while waves sensing was based on a laser Doppler vibrometer. The excitation frequency was equal to 40 kHz. An optimal ACT slope angle for the generation of elastic waves mode was determined with the aid of dispersion curves calculated by using a semi-analytical model. Due to the stack sequence in the composite plate (unidirectional composite), ACT slope angles were different for waves generation in the direction along and across reinforcing fibers direction. Moreover, experimental verification of the optimal ACT slope angles was conducted. It was possible to generate A0 wave mode in the direction along and across the reinforcing fibers. Optimal angles determined using ACT were equal to 16° (along fibers) and 34° (across fibers). In the case of optimal angles, elastic waves amplitudes are almost two times higher than for the case of ACT oriented perpendicularly to the plate surface. Moreover, experimental results based on ACT showed that it was possible to generate the SH0 mode in the direction across the fiber for optimal angles equal to 10°. Finally, based on the A0 wave mode propagation, the process for localization of discontinuities was performed. Discontinuities in the form of additional mass simulating damage were investigated. A simple signal processing algorithm based on elastic wave energy was used for creating damage maps. Authors compared discontinuity localization for ACT oriented perpendicularly to the plate and at the optimal slope angle. The utilization of non-contact waves excitation at optimal ACT slope angles helped to focus the wave energy in the desired direction. Moreover, in this case, elastic waves with the highest amplitudes were generated.