bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Chemical Pollutants and Ecological Reconstruction Methods in the Tismana I Quarry, Rovinari Basin, Romania
Authors: Matei Oana-Raluca , Dumitrescu Silaghi Luminița , Dunca Emilia-Cornelia , Bungau Simona Gabriela , Tit Delia Mirela , Mosteanu Danut-Eugeniu , Hodis Ruxandra
Published: June 2022

The phytoremediation of polluted land in Romania is based on research on biodiversity, environmental protection, and the sustainable use of natural or man-made resources, carried out by universities and research institutes for over 30 years, synchronized with those at the European and global level. The aim of this paper is to establish the categories of pollutants with potential environmental, economic, and social impacts associated with mining in order to choose the optimal method of ecological reconstruction. In this regard, the Tismana quarry was mapped, the surface of the analysis plot was set at 50 m × 50 m, and the sampling depth was 0–20 cm; from each plot, two samples were collected. Out of a total of 121 analysis plots, ten susceptible plots were identified, from which 20 samples were collected and analyzed. The samples were analyzed by the UV-VIS spectrophotometer method—MLUV1720 and UV spectrometry—with a SHIMADZU UV 160U spectrophotometer; they indicated in only three analysis plots a pollution with phenols, Ni, Zn, Ni and HAP, the concentrations of which exceeded only the normal values, which does not affect the eaves threshold and intervention for the type of land use. Being point pollution, the phytoremediation of these soils can be achieved in a short time. The paper aims to present the situation of chemical pollutants in the Tismana quarry area, and to offer different ecological rehabilitation solutions depending on their presence.
How Agricultural Extension Services Improve Farmers’ Organic Fertilizer Use in China? The Perspective of Neighborhood Effect and Ecological Cognition
Authors: Qiao Dan , Li Ningjie , Cao Li , Zhang Desheng , Zheng Yanan , Xu Tao
Published: June 2022

Improving farmers’ usage of organic fertilizer is critical for the green and high-quality development of China’s agriculture. Based on 492 mango farmers’ survey data in Hainan Province, this paper uses an endogenous switching regression (ESR)model, empirically analyzes the impact of agricultural extension services on farmers’ willingness to use organic fertilizer, and further investigates the mediating role of ecological cognition and the moderating role of neighborhood effect in the influence mechanism. Results show agricultural extension services have a significant positive effect on farmers’ willingness to use organic fertilizer, ecological cognition has a partial mediating effect in the influence mechanism, which accounts for 17.84% of the total effect. The neighborhood effect has a positive moderating effect in the influence mechanism of ecological cognition on farmers’ willingness to use organic fertilizer. These results imply that agricultural extension services play a significant role in China’s sustainable agricultural development and by improving their awareness and taking advantage of the neighborhood effect, we can stimulate farmers’ willingness to green production. The study also puts forward policy recommendations on further promoting farmers’ use of organic fertilizer.
Modeling the Driving Factors of the Value Added in the Chinese Sports Industry: A Ridge Regression
Authors: Li Jiaomu , Huang Sen , Min Sicheng , Bu Te
Published: June 2022

The development of a high-quality sports industry is crucial to China’s economic growth. This research quantitatively analyzed factors influencing the development of the sports industry for the period 2010–2019. The study selected variables pertaining to the gross national income per capita (X1), household final consumption expenditure per capita (X2), sports population (X3), number of fitness venues and facilities (X4), number of sporting events (X5), and number of sports-related business registrations (X6) and analyzed their relationship with the value added to the sports industry. By developing a ridge regression model, it can be determined that correlations (Pearson’s r) between six factors and the value added to the sports industry were all greater than 0.90, and that each factor had a positive impact on the industry (p < 0.05). After standardizing the ridge regression model with the z-score method, it was determined that the degree of influence of the six factors varied: X2 (βridge = 0.156), X3 (βridge = 0.153) and X5 (βridge = 0.153), X1 (βridge = 0.151), X4 (βridge = 0.136), and X6 (βridge = 0.121). The ridge regression model can give a reference model for predicting and optimizing the sustainable development of the sports industry in China.
Collaborative Learning in the Flipped University Classroom: Identifying Team Process Factors
Authors: Shin Suhkyung , Kwon Kyungbin , Jung Jiyoon
Published: June 2022

The purpose of this study was to examine how team process factors relate to students’ self-efficacy, attitude, and learning satisfaction in flipped learning. Since lone-wolf students tend to have little patience for the group work process and exhibit a lack of organizational commitment, this study also explores how students’ preferences for collaborative work or individual work affect their self-efficacy, attitude, and learning satisfaction in a flipped classroom. The participants were thirty-four undergraduate students enrolled in a consumer behavior course offered by a school of business at a university in Seoul, South Korea. Data were collected through surveys that measured team process, lone-wolf tendencies, self-efficacy, and attitude during the course. The results show the factor of team trust had a significant negative correlation with the lone-wolf measure but a positive correlation with responsibility, communication, cognitive and social competency, and self-efficacy. Moreover, communication and responsibility were positive predictors of self-efficacy and attitude. These results imply the usefulness of identifying critical variables of individual difference, such as lone-wolf tendencies, that could lead to both dysfunctional team process and low outcomes. Based on the results, this study provides implications for structuring and managing team projects in a higher education setting.
Gender Diversity and Firms’ Sustainable Performance: Moderating Role of CEO Duality in Emerging Equity Market
Authors: Zhu Chengpeng , Husnain Muhammad , Ullah Saif , Khan Muhammad Tasnim , Ali Waris
Published: June 2022

The objective of the study is to investigate the impact of female representation on boards and female CEOs on firms’ sustainable performance in the context of an emerging economy. We also introduce the CEO duality as a moderator variable between sustainable firm performance and board gender diversity. For this purpose, the study uses a panel data sample from 2005 to 2020 for non-financial listed firms in Pakistan. We use the firm’s operational self-sufficiency for the sustainable performance of firms. For robustness, the study also uses other accounting-based and market-based proxies. We apply the static (fixed and random effect) and dynamic panel estimation (GMM) techniques to deal with the heterogeneity and dynamic endogeneity issues in panel data estimation. The finding shows a significant positive impact of female directors on board and female CEOs on sustainable performance, whereas CEO duality does not moderate this relationship. Furthermore, we find that CEO duality has a significant negative impact on firms’ sustainable performance, which supports the agency theory hypothesis. The study also controls corporate board level factors, including board size and board independence, and uses leverage, firm size, capital expenditure, and tangible assets as firm-level control. The results also reveal that board size and board independence have a significant positive impact on firms’ sustainable performance. Furthermore, firm size, tangibility, and firm age have a significant positive, whereas leverage and capital expenditure have a negative impact on firms’ sustainable performance. Finally, the study has policy implications for stakeholders.
Effect of hukou Accessibility on Migrants’ Long Term Settlement Intention in Destination
Authors: Li Peilin , Wu Yufeng , Ouyang Hui
Published: June 2022

Migrants’ long-term settlement intention in urban areas has been emphasized by both policy makers and researchers in promoting urbanization and coordinating regional economic development. This study advances the body of knowledge by investigating the effect of what E.S. Lee has proposed as ‘intervening obstacles’ in the ‘push-and-pull’ theory—the difficulty in obtaining hukou in migration destination, on their long-term settlement intention in urban areas. Logistic regressions were applied to examine the effect of urban registered residence system (the hukou system) accessibility on migrants’ long-term settlement intention in urban areas, as well as the determinants of subjective evaluated difficulty in obtaining urban hukou, based on a nation-wide large-scale survey in 46 Chinese cities. Our results suggest that difficulty in obtaining urban hukou does play an important role in shaping country-wide population movement. However, the negative impact of hukou difficulty on migrant workers’ residence intention is not linear, and only when the threshold in obtaining hukou is too high and difficult to achieve will migrant workers choose to return to their hometown in the long term. Moreover, the subjective evaluation of difficulty is further influenced by personal capability and living conditions in cities. This study provides pragmatic implications for administrations from either push side or pull side to improve habitant-related development strategies.
Research on Maximum Penetration Ratio of Wind Power under the Voltage Stability Margin Constraint
Authors: Lei Cheng , Wu Yaning , Huang Yu , Liang Yu , Nie Jinfeng , Tang Muyi , Yi Xuancheng , Luo Yi
Published: June 2022

With the large-scale integration of wind power, the voltage stability problem in the power system has become increasingly prominent. Therefore, this paper studies the maximum penetration ratio of wind power from the perspective of voltage stability. Firstly, the mathematical grid-connection model of the wind generator is established. Secondly, using the impedance modulus margin index (IMMI) and the Thevenin model, the analytical calculation method for maximum wind power penetration under the voltage stability margin constraint is proposed with theoretical derivation. Then, a typical case study is used to verify the feasibility and effectiveness of the proposed method. Finally, based on this, the key factors affecting the wind power penetration limit are analyzed from the source–grid–load side, and practical engineering measures to improve the maximum penetration ratio of wind power are summarized. This research will be helpful for the planning and operation of the high-proportion renewable energy power systems.
Searching for New Physics in Hadronic Final States with Run 2 Proton–Proton Collision Data at the LHC
Authors: Schramm Steven
Published: June 2022

The symmetries of the Standard Model give rise to the forces that act on particles, and the corresponding force mediators. While the Standard Model is an excellent description of particle interactions, it has known limitations; it is therefore important to search for new physics beyond the Standard Model, potentially indicating as-of-yet unknown symmetries of nature. The ATLAS and CMS collaborations have detailed physics programmes, involving a large number of searches for new physics in hadronic final states. As the start of Run 3 of the LHC is imminent, now is a good time to review the progress made and the status of hadronic searches during Run 2 at a centre-of-mass collision energy of s=13TeV. This review provides an overview of the motivations and challenges of hadronic final states at the LHC, followed by an introduction to jet reconstruction, calibration, and tagging. Three classes of searches for new physics in hadronic final states are discussed: di-jet searches, searches for missing transverse momentum in association with another object, and searches for hadronic di-boson resonances. The complementarity of these different analysis strategies is discussed, emphasising the importance of a varied hadronic physics programme in the search for new physics.
Constructing Dixon Matrix for Sparse Polynomial Equations Based on Hybrid and Heuristics Scheme
Authors: Deng Guoqiang , Qi Niuniu , Tang Min , Duan Xuefeng
Published: June 2022

Solving polynomial equations inevitably faces many severe challenges, such as easily occupying storage space and demanding prohibitively expensive computation resources. There has been considerable interest in exploiting the sparsity to improve computation efficiency, since asymmetry phenomena are prevalent in scientific and engineering fields, especially as most of the systems in real applications have sparse representations. In this paper, we propose an efficient parallel hybrid algorithm for constructing a Dixon matrix. This approach takes advantage of the asymmetry (i.e., sparsity) in variables of the system and introduces a heuristics strategy. Our method supports parallel computation and has been implemented on a multi-core system. Through time-complexity analysis and extensive benchmarks, we show our new algorithm has significantly reduced computation and memory overhead. In addition, performance evaluation via the Fermat–Torricelli point problem demonstrates its effectiveness in combinatorial geometry optimizations.
Bayesian P-Splines Quantile Regression of Partially Linear Varying Coefficient Spatial Autoregressive Models
Authors: Chen Zhiyong , Chen Minghui , Ju Fangyu
Published: June 2022

This paper deals with spatial data that can be modelled by partially linear varying coefficient spatial autoregressive models with Bayesian P-splines quantile regression. We evaluate the linear and nonlinear effects of covariates on the response and use quantile regression to present comprehensive information at different quantiles. We not only propose an empirical Bayesian approach of quantile regression using the asymmetric Laplace error distribution and employ P-splines to approximate nonparametric components but also develop an efficient Markov chain Monte Carlo technique to explore the joint posterior distributions of unknown parameters. Monte Carlo simulations show that our estimators not only have robustness for different spatial weight matrices but also perform better compared with quantile regression and instrumental variable quantile regression estimators in finite samples at different quantiles. Finally, a set of Sydney real estate data applications is analysed to illustrate the performance of the proposed method.
Cornish–Fisher-Based Control Charts Inclusive of Skewness and Kurtosis Measures for Monitoring the Mean of a Process
Authors: Braden Paul , Matis Timothy
Published: June 2022

In this paper, we propose control limits for monitoring the mean of a process variable based on a first and second order Cornish–Fisher expansion, which limits are inclusive of its skewness and kurtosis measures, respectively. These are shown to have better in-control error performance than other limits that were similarly derived from this expansion with smoothing functions, both when these measures are assumed to be known and estimated from sample data. The range of measure specifications where the underlying Cornish–Fisher function is monotonic is derived. Operating characteristic curves for select cases demonstrate the associated out-of-control error performance. The Cornish–Fisher limits are applied to a real-life dataset in developing a control chart for monitoring the mean lifetime of car brake pads, wherein they are compared to other limit approximations.
Off-Shell Probes of the Higgs Yukawa Couplings: Light Quarks and Charm
Authors: Vignaroli Natascia
Published: June 2022

We review the present status and the future prospects for the measurements of the Higgs Yukawa couplings to light quarks and charm. A special focus is given to new proposed off-shell probes, which offer promising and complementary opportunities to test light quark Yukawas in triboson final states. Additionally, a new off-shell strategy to test the charm Yukawa coupling in the final state with two bosons plus a charm and a jet is considered. First estimates for the HL-LHC and the FCC-hh sensitivities on the channel are presented, showing encouraging results.
Lax Operator Algebras and Applications to τ-Symmetries for Multilayer Integrable Couplings
Authors: Li Chun-Xia , Ma Wen-Xiu , Shen Shou-Feng
Published: June 2022

The algebraic structures of zero curvature representations are furnished for multilayer integrable couplings associated with matrix spectral problems, both discrete and continuous. The key elements are a class of matrix loop algebras consisting of block matrices with blocks of the same size. As illustrative examples, isospectral and non-isospectral integrable couplings and the corresponding commutator relations of their Lax operators are computed explicitly in the cases of the Volterra lattice hierarchy and the AKNS hierarchy, along with their τ-symmetry algebras.
The Generalized Competition Indices of Doubly Symmetric Primitive Digraphs with d Loops
Authors: Chen Danmei , Li Xiangjun
Published: June 2022

Let DSn(d) denote the set of all doubly symmetric primitive digraphs of order n with d loops, where d is an integer and 1≤d≤n. In this paper, we determine the upper bounds for the m-competition indices(generalized competition indices) of DSn(d), where 1≤m≤n. If n and d satisfy that n is odd and d is odd, or n≤2d−2 and d is even such that d≥2, then the upper bounds for the m-competition indices of DSn(d) can be reached, where 1≤m≤n.
On The 3D VR Simulated Rubik’s Cube Game for Smart Pads
Authors: Chang Wen-Te
Published: June 2022

In this study, interface designs of a VR 3D-simulated Rubik’s Cube game were developed and evaluated. A 2 × 2 × 2 mixed-design ANOVA was executed, with age (younger adult/older adult), interface (arrow/intuitive), and task complexity (easy, a single symmetrical task/difficult, a bio-symmetrical task) experimental design. The first three factors were between-subject designs while the latter was a within-subject design. The dependent variable was the percentage of the task performance and wayfinding questionnaire. The collected experimental data were analyzed by regression method to clarify the correlation among age, interface, task complexity, and wayfinding strategy. There were 96 subjects in the experiment, including 48 younger adults (aged from 18~22) and 48 older adults (aged from 60~85). The experimental results and statistical analysis showed that the task difficulty had a significant effect on task performance in the 3D VR Rubik’s Cube game. For the smart pad, the arrow interface was significantly more effective than the intuitive interface. The theoretical model regression analysis of the task complexity, interface, and wayfinding strategy was shown to be significant. Results showed that users may be affected either positively or negatively by the wayfinding strategy, as a higher score on familiarity indicates better VR game task performance, whereas for the usual spatial behavior wayfinding strategy, the opposite result was found for memory. These results can be used to assess VR game interface designs, taking into consideration age difference, task complexity, experiential self-report on 3D VR games, and including VR rotation navigational
Spin Interference Effects in a Ring with Rashba Spin-Orbit Interaction Subject to Strong Light–Matter Coupling in Magnetic Field
Authors: Pudlak Michal , Nazmitdinov R.
Published: June 2022

Electron transport through a one-dimensional quantum ring, subjected to Rashba spin–orbit interaction and connected with two external leads, is studied in the presence of external fields. They include the optical radiation, produced by an off-resonant high-frequency electric field, and a perpendicular magnetic field. By means of the Floquet theory of periodically driven quantum systems the interference effects under these fields are described in detail. It is found analytically the specific conditions to reach the spin-filtering effect, caused by the interplay of the external fields and Rashba spin-orbit interaction.
Asymmetry Evaluation of Sea Cucumber (Apostichopus japonicus) Gut and Its Surrounding Environment in the Bacterial Community
Authors: Zhang Jingjing , Zhou Yeqing , Wang Luo , Liu Yanxia , Lin Zhiping , Hao Zhenlin , Ding Jun , Chang Yaqing
Published: June 2022

Animals are not only regulated by their own genes but also influenced by symbiotic bacteria, most of which are colonized in the gut. The gut bacterial community is involved in plenty of physiological processes; therefore, intestinal colonization by commensal microbiota is essential to the health of the host animal. Here, metagenome sequencing of the A. japonicus gut, surrounding water, and feed was performed to explore the structural and functional characteristics of the colonized bacteria in the gut of A. japonicus. Results showed that Bacteroidetes and Proteobacteria were the main dominant phyla of the A. japonicus gut, and Formosa, Vibrio, and Lactobacillus were the dominant genera. There was asymmetry between the A. japonicus gut and its surrounding environment in the bacterial community. In terms of the top 50 abundant genera, those colonized in the gut shared a similarity of 26% with those colonized in the surrounding water and a similarity of 30% with those colonized in the feed. According to KEGG annotation, the dominant metabolic pathways in the gut of A. japonicus were glycan biosynthesis and metabolism, nitrogen metabolism, and cysteine and methionine metabolism. This implies that the gut-colonized bacteria of A. japonicus are influenced by the surrounding water and the feed. In addition, the gut-colonized bacteria might be related to the growth and metabolism of A. japonicus.
Statistical Assessment of Low-Cycle Fatigue Durability
Authors: Bazaras Žilvinas , Lukoševičius Vaidas
Published: June 2022

This article presents an experimental–analytical statistical study of low-cycle fatigue to crack initiation and complete failure. The application of statistical and probability methods provides for the possibility of improving the characteristics related to the structural life and the justification for the respective values of cyclic loads in the design stage. Most studies investigating statistical descriptions of crack initiation or complete failure do not analyse the distribution of the characteristics, correlation relationships, and statistical parameters of low-cycle fatigue. Low-cycle failure may be quasistatic or (due to the fatigue) transient. Materials with contrasting cyclic properties were selected for the investigation: cyclically softening alloyed steel 15Cr2MoVA; cyclically stable structural steel C45; cyclically hardening aluminium alloy D16T1. All samples were produced in a single batch of each respective material to reduce the distribution of data. The lowest values of the variation coefficient of one of the key statistical indicators were obtained using the log-normal distribution, which is superior to the normal or Weibull distribution. Statistical analysis of the durability parameters showed that the distribution was smaller than the parameters of the distribution of the deformation diagram. The results obtained in the study enable the verification of durability and life of the structural elements of in-service facilities subjected to elastoplastic loading by assessing the distribution of characteristics of crack initiation and failure and low-cycle strain parameters as well as the permissible distribution limits.
On Spectral Characterization of Two Classes of Unicycle Graphs
Authors: Yin Jun , Zhao Haixing , Ma Xiujuan , Liang Jing
Published: June 2022

Let G be a graph with n vertices, let A(G) be an adjacency matrix of G and let PA(G,λ) be the characteristic polynomial of A(G). The adjacency spectrum of G consists of eigenvalues of A(G). A graph G is said to be determined by its adjacency spectrum (DS for short) if other graphs with the same adjacency spectrum as G are isomorphic to G. In this paper, we investigate the spectral characterization of unicycle graphs with only two vertices of degree three. We use G21(s1,s2) to denote the graph obtained from Q(s1,s2) by identifying its pendant vertex and the vertex of degree two of P3, where Q(s1,s2) is the graph obtained by identifying a vertex of Cs1 and a pendant vertex of Ps2. We use G31(t1,t2) to denote the graph obtained from circle with the vertices v0v1⋯vt1+t2+1 by adding one pendant edge at vertices v0 and vt1+1, respectively. It is shown that G21(s1,s2) (s1≠4,6, s1≥3, s2≥3) and G31(t1,t2) (t1+t2≠2, t2≥t1≥1) are determined by their adjacency spectrum.
Nonlinear Dependence and Spillovers between Currency Markets and Global Economic Variables
Authors: Jiang Zhuhua , Arreola Hernandez Jose , McIver Ron P. , Yoon Seong-Min
Published: June 2022

The widespread integration and growing systemic dependence among currency, stock, and commodity markets render these markets often very vulnerable to shocks and at risk of collapse at the same time. As a result, these trends threaten the sustainability of the entire financial system. In this study, we aim to explore the spillovers and nonlinear dependencies between the seven major foreign exchange rates, crude oil and gold prices, a global stock price index, and oil and stock implied volatility indices as proxy variables for global risk factors by employing a directional spillover network approach. We also use a multi-scale decomposition method and nonlinear causality test between these variables to capture multi-level relationships at short and long horizons. The major findings are summarized as follows. First, from the multi-scale decomposition analysis, we identify that Granger causality test results and the direction and strength of return spillovers change with the level of decomposition. Second, the results of nonlinear causality tests show variation in both the significance and direction of Granger causality relationships between the decomposed currency and other series at different timescales, especially for the decomposed oil, gold, and OVX series. Third, the measured directional spillover indices identify the Euro–Dollar exchange rate as the largest contributor of connectedness to the other series.
Scientific Evidence about the Risks of Micro and Nanoplastics (MNPLs) to Human Health and Their Exposure Routes through the Environment
Authors: Rodrigues Ana Clara Bastos , de Jesus Gabriel Pereira , Waked Dunia , Gomes Gabriel Leandro , Silva Thamires Moraes , Yariwake Victor Yuji , da Silva Mariane Paula , Magaldi Antônio José , Veras Mariana Matera
Published: June 2022

Nowadays, a large amount and variety of plastic is being produced and consumed by human beings on an enormous scale. Microplastics and nanoplastics (MNPLs) have become ubiquitous since they can be found in many ecosystem components. Plastic particles can be found in soil, water, and air. The routes of human exposure are numerous, mainly involving ingestion and inhalation. Once ingested, these particles interact with the gastrointestinal tract and digestive fluids. They can adsorb substances such as additives, heavy metals, proteins, or even microorganisms on their surface, which can cause toxicity. During inhalation, they can be inhaled according to their respective sizes. Studies have reported that exposure to MNPLs can cause damage to the respiratory tract, creating problems such as bronchitis, asthma, fibrosis, and pneumothorax. The reports of boards and committees indicate that there is little data published and available on the toxicity of MNPLs as well as the exposure levels in humans. Despite the well-established concept of MNPLs, their characteristics, and presence in the environment, little is known about their real effects on human health and the environment.
Evaluation of the Toxicity and Sublethal Effects of Acetamiprid and Dinotefuran on the Predator Chrysopa pallens (Rambur) (Neuroptera: Chrysopidae)
Authors: Su Yue , Ren Xiangliang , Ma Xiaoyan , Wang Dan , Hu Hongyan , Song Xianpeng , Cui Jinjie , Ma Yan , Yao Yongsheng
Published: June 2022

Neonicotinoid insecticides affect the physiology or behavior of insects, posing risks to non-target organisms. In this study, the effects of sublethal doses of two neonicotinoid insecticides, acetamiprid and dinotefuran, against Chrysopa pallens (Rambur) (Neuroptera: Chrysopidae) were determined and compared. The results showed that acetamiprid and dinotefuran at LD10 (8.18 ng a.i. per insect and 9.36 ng a.i. per insect, respectively) and LD30 (16.84 ng a.i. per insect and 15.01 ng a.i. per insect, respectively) significantly prolonged the larval stages and pupal stages (except acetamiprid LD10), compared to control. In addition, acetamiprid and dinotefuran at LD30 significantly prolonged the adult preoviposition period (APOP) and total preoviposition period (TPOP). In contrast, the two insecticides at LD10 and LD30 had no significant effect on the longevity, fecundity, reproductive days, preadult survival rate (%), intrinsic rate of increase (r), net reproductive rate (R0), and finite rate of increase (λ). These results provide a theoretical basis for the rational use of these two insecticides and the utilization and protection of C. pallens.
Improving the Risk Assessment of Pesticides through the Integration of Human Biomonitoring and Food Monitoring Data: A Case Study for Chlorpyrifos
Authors: Tarazona Jose V. , González-Caballero Maria del Carmen , Alba-Gonzalez Mercedes de , Pedraza-Diaz Susana , Cañas Ana , Dominguez-Morueco Noelia , Esteban-López Marta , Cattaneo Irene , Katsonouri Andromachi , Makris Konstantinos C. , Halldorsson Thorhallur I. , Olafsdottir Kristin , Zock Jan-Paul , Dias Jonatan , Decker Annelies De , Morrens Bert , Berman Tamar , Barnett-Itzhaki Zohar , Lindh Christian , Gilles Liese , Govarts Eva , Schoeters Greet , Weber Till , Kolossa-Gehring Marike , Santonen Tiina , Castaño Argelia
Published: June 2022

The risk assessment of pesticide residues in food is a key priority in the area of food safety. Most jurisdictions have implemented pre-marketing authorization processes, which are supported by prospective risk assessments. These prospective assessments estimate the expected residue levels in food combining results from residue trials, resembling the pesticide use patterns, with food consumption patterns, according to internationally agreed procedures. In addition, jurisdictions such as the European Union (EU) have implemented large monitoring programs, measuring actual pesticide residue levels in food, and are supporting large-scale human biomonitoring programs for confirming the actual exposure levels and potential risk for consumers. The organophosphate insecticide chlorpyrifos offers an interesting case study, as in the last decade, its acceptable daily intake (ADI) has been reduced several times following risk assessments by the European Food Safety Authority (EFSA). This process has been linked to significant reductions in the use authorized in the EU, reducing consumers’ exposure progressively, until the final ban in 2020, accompanied by setting all EU maximum residue levels (MRL) in food at the default value of 0.01 mg/kg. We present a comparison of estimates of the consumer’s internal exposure to chlorpyrifos based on the urinary marker 3,5,6-trichloro-2-pyridinol (TCPy), using two sources of monitoring data: monitoring of the food chain from the EU program and biomonitoring of European citizens from the HB4EU project, supported by a literature search. Both methods confirmed a drastic reduction in exposure levels from 2016 onwards. The margin of exposure approach is then used for conducting retrospective risk assessments at different time points, considering the evolution of our understanding of chlorpyrifos toxicity, as well as of exposure levels in EU consumers following the regulatory decisions. Concerns are presented using a color code, and have been identified for almost all studies, particularly for the highest exposed group, but at different levels, reaching the maximum level, red code, for children in Cyprus and Israel. The assessment uncertainties are highlighted and integrated in the identification of levels of concern.
Associations between Polyfluoroalkyl Substances Exposure and Breast Cancer: A Meta-Analysis
Authors: Jiang Haihong , Liu Huan , Liu Ge , Yu Jing , Liu Nana , Jin Yunqin , Bi Yongyi , Wang Hong
Published: June 2022

Polyfluoroalkyl substances (PFASs) are persistent pollutants that may cause breast cancer. However, associations between exposure to PFASs and the risk of breast cancer are controversial. We retrieved studies on the association between PFASs—perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS)—and breast cancer risk in women from PubMed, Embase, and the Web of Science. The pooled odds ratios (ORs) or relative risks (RRs) and their 95% confidence intervals (CIs) were extracted or calculated from provided data. Moreover, subgroup and metaregression analyses were performed to distinguish the potential sources of heterogeneity between studies. Lastly, eight original studies were included in the meta-analysis. PFOA and PFHxS were positively correlated with breast cancer risk, and the pooled ORs (and 95% CIs) were 1.32 (1.19 and 1.46) and 1.79 (1.51 and 2.11), respectively. PFNA was negatively correlated with breast cancer risk and the pooled OR (and 95% CIs) was 0.76 (0.6 and 0.96), and PFOS was shown to have no correlation with breast cancer risk and the pooled OR (and 95% CIs) was 1.01 (0.87 and 1.17). All results were merged in a random-effects model with significant heterogeneities (I2 > 90%, p < 0.001). The results demonstrated that PFASs might be potential risk factors for breast cancer, and the compounds in low exposure levels could have a more harmful impact on human health.
The Survival Response of Earthworm (Eisenia fetida L.) to Individual and Binary Mixtures of Herbicides
Authors: Samadi Kalkhoran Elham , Alebrahim Mohammad Taghi , Mohammaddoust Chamn Abad Hamid Reza , Streibig Jens Carl , Ghavidel Akbar , Tseng Te-Ming Paul
Published: June 2022

Frequent use of herbicides may impose a risk on non-target species. The objective was to test the combined toxic effect of binary herbicide mixtures—metribuzin:halosulfuron and metribuzin:flumioxazin—on non-target earthworms in two test systems: filter paper and a soil toxicity test system. The joint action experiments were independently run twice to substantiate the findings. The most potent individual herbicide was metribuzin, with a 50% lethal concentration (LC50) of 17.17 µg ai. cm−2 at 48 h in the filter paper test. The toxicity of the individual herbicides on the filter paper test was ranked as metribuzin>halosulfuron>flumioxazin. In the soil test, metribuzin and halosulfuron had high toxicity with an LC50 of 8.48 and 10.08 mg ai. kg−1, respectively, on day 14. Thus, the individual herbicide ranking did not change between the filter paper and artificial soil tests. The herbicide’s mixed effect in both test systems showed a consistent antagonistic effect relative to a Concentration Addition reference model. It indicates that the mixtures retracted the herbicide’s action in the earthworms.
In-Depth Characterization of a Re-Engineered Cholera Toxin Manufacturing Process Using Growth-Decoupled Production in Escherichia coli
Authors: Danielewicz Natalia , Dai Wenyue , Rosato Francesca , Webb Michael E. , Striedner Gerald , Römer Winfried , Turnbull W. Bruce , Mairhofer Juergen
Published: June 2022

Non-toxic derivatives of the cholera toxin are extensively used in neuroscience, as neuronal tracers to reveal the location of cells in the central nervous system. They are, also, being developed as vaccine components and drug-delivery vehicles. Production of cholera-toxin derivatives is often non-reproducible; the quality and quantity require extensive fine-tuning to produce them in lab-scale settings. In our studies, we seek a resolution to this problem, by expanding the molecular toolbox of the Escherichia coli expression system with suitable production, purification, and offline analytics, to critically assess the quality of a probe or drug delivery, based on a non-toxic derivative of the cholera toxin. We present a re-engineered Cholera Toxin Complex (rCTC), wherein its toxic A1 domain was replaced with Maltose Binding Protein (MBP), as a model for an rCTC-based targeted-delivery vehicle. Here, we were able to improve the rCTC production by 11-fold (168 mg/L vs. 15 mg/L), in comparison to a host/vector combination that has been previously used (BL21(DE3) pTRBAB5-G1S). This 11-fold increase in the rCTC production capability was achieved by (1) substantial vector backbone modifications, (2) using Escherichia coli strains capable of growth-decoupling (V strains), (3) implementing a well-tuned fed-batch production protocol at a 1 L scale, and (4) testing the stability of the purified product. By an in-depth characterization of the production process, we revealed that secretion of rCTC across the E. coli Outer Membrane (OM) is processed by the Type II secretion-system general secretory pathway (gsp-operon) and that cholera toxin B-pentamerization is, likely, the rate-limiting step in complex formation. Upon successful manufacturing, we have validated the biological activity of rCTC, by measuring its binding affinity to its carbohydrate receptor GM1 oligosaccharide (Kd = 40 nM), or binding to Jurkat cells (93 pM) and delivering the cargo (MBP) in a retrograde fashion to the cell.
Genotoxicity of 12 Mycotoxins by the SOS/umu Test: Comparison of Liver and Kidney S9 Fraction
Authors: Alonso-Jauregui Maria , González-Peñas Elena , López de Cerain Adela , Vettorazzi Ariane
Published: June 2022

Liver S9 fraction is usually employed in mutagenicity/genotoxicity in vitro assays, but some genotoxic compounds may need another type of bioactivation. In the present work, an alternative S9 fraction from the kidneys was used for the genotoxicity assessment of 12 mycotoxins with the SOS/umu test. The results were compared with liver S9 fraction, and 2–4 independent experiments were performed with each mycotoxin. The expected results were obtained with positive controls (4-nitroquinoline-N-oxide and 2-aminoanthracene) without metabolic activation or with liver S9, but a potent dose-dependent effect with 4-nitroquinoline-N-oxide and no activity of 2-aminoanthracene with kidney S9 were noticed. Aflatoxin B1 was genotoxic with metabolic activation, the effect being greater with liver S9. Sterigmatocystin was clearly genotoxic with liver S9 but equivocal with kidney S9. Ochratoxin A, zearalenone and fumonisin B1 were negative in all conditions. Trichothecenes were negative, except for nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, T-2 and HT-2 toxins, which showed equivocal results with kidney S9 because a clear dose-response effect was not observed. Most of the mycotoxins have been assessed with kidney S9 and the SOS/umu test for the first time here. The results with the positive controls and the mycotoxins confirm that the organ used for the S9 fraction preparation has an influence on the genotoxic activity of some compounds.
Liza ramada Juveniles after Exposure to the Toxic Dinoflagellate Vulcanodinium rugosum: Effects on Fish Viability, Tissue Contamination and Microalgae Survival after Gut Passage
Authors: Bouquet Aurélien , Perdrau Marie Anaïs , Laabir Mohamed , Foucault Elodie , Chomérat Nicolas , Rolland Jean Luc , Abadie Eric
Published: June 2022

Pinnatoxins (PnTX) and Portimines (Prtn), two toxins produced by the benthic dinoflagellate Vulcanodinium rugosum, are known to be lethal to mice after intraperitoneal or oral administration. They are also known to accumulate in shellfish such as mussels and clams, but their effect on fish and the upper food chain remains unknown. In this work, juveniles of the fish Liza ramada (Mullet) were exposed to a strain of V. rugosum producing PnTX G and Prtn A. The fishes’ viability and contamination were recorded at times interval. Results showed that L. ramada juveniles were able to feed on V. rugosum and that their tissues could be contaminated by PnTX G and Prtn A without impact on fish viability. Furthermore, the microalgae temporary cysts survived and germinated after fish gut passage. This study showed the potential of L. ramada to transfer PnTX and Prtn toxins to the upper food chain and to disseminate V. rugosum in environment.
Interplay of HCPro and CP in the Regulation of Potato Virus A RNA Expression and Encapsidation
Authors: Saha Shreya , Lõhmus Andres , Dutta Pinky , Pollari Maija , Mäkinen Kristiina
Published: June 2022

Potyviral coat protein (CP) and helper component-proteinase (HCPro) play key roles in both the regulation of viral gene expression and the formation of viral particles. We investigated the interplay between CP and HCPro during these viral processes. While the endogenous HCPro and a heterologous viral suppressor of gene silencing both complemented HCPro-less potato virus A (PVA) expression, CP stabilization connected to particle formation could be complemented only by the cognate PVA HCPro. We found that HCPro relieves CP-mediated inhibition of PVA RNA expression likely by enabling HCPro-mediated sequestration of CPs to particles. We addressed the question about the role of replication in formation of PVA particles and gained evidence for encapsidation of non-replicating PVA RNA. The extreme instability of these particles substantiates the need for replication in the formation of stable particles. During replication, viral protein genome linked (VPg) becomes covalently attached to PVA RNA and can attract HCPro, cylindrical inclusion protein and host proteins. Based on the results of the current study and our previous findings we propose a model in which a large ribonucleoprotein complex formed around VPg at one end of PVA particles is essential for their integrity.
Genomic Diversity of SARS-CoV-2 Omicron Variant in South American Countries
Authors: Luna Nicolas , Muñoz Marina , Ramírez Angie L. , Patiño Luz H. , Castañeda Sergio Andres , Ballesteros Nathalia , Ramírez Juan David
Published: June 2022

Genomic surveillance of SARS-CoV-2 is one of the tools that provide genomic information on circulating variants. Given the recent emergence of the Omicron (B.1.1.529) variant, this tool has provided data about this lineage’s genomic and epidemiological characteristics. However, in South America, this variant’s arrival and genomic diversity are scarcely known. Therefore, this study determined the genomic diversity and phylogenetic relationships of 21,615 Omicron genomes available in public databases. We found that in South America, BA.1 (n = 15,449, 71%) and BA.1.1 (n = 6257, 29%) are the dominant sublineages, with several mutations that favor transmission and antibody evasion. In addition, these lineages showed cryptic transmission arriving on the continent in late September 2021. This event may have contributed to the dispersal of Omicron sublineages and the acquisition of new mutations. Considering the genomic and epidemiological characteristics of these lineages, especially those with a high number of mutations in their genome, it is important to conduct studies and surveillance on the dynamics of these lineages to identify the mechanisms of mutation acquisition and their impact on public health.
The Evolution, Genomic Epidemiology, and Transmission Dynamics of Tembusu Virus
Authors: Cui Yongqiu , Pan Yang , Guo Jinshuo , Wang Dedong , Tong Xinxin , Wang Yongxia , Li Jingyi , Zhao Jie , Ji Ying , Wu Zhi , Zeng Penghui , Zhou Jianwei , Feng Xufei , Hou Lei , Liu Jue
Published: June 2022

Tembusu virus (TMUV) can induce severe egg drop syndrome in ducks, causing significant economic losses. In this study, the possible origin, genomic epidemiology, and transmission dynamics of TMUV were determined. The time to the most recent common ancestor of TMUV was found to be 1924, earlier than that previously reported. The effective population size of TMUV increased rapidly from 2010 to 2013 and was associated with the diversification of different TMUV clusters. TMUV was classified into three clusters (clusters 1, 2, and 3) based on the envelope (E) protein. Subcluster 2.2, within cluster 2, is the most prevalent, and the occurrence of these mutations is accompanied by changes in the virulence and infectivity of the virus. Two positive selections on codons located in the NS3 and NS5 genes (591 of NS3 and 883 of NS5) were identified, which might have caused changes in the ability of the virus to replicate. Based on phylogeographic analysis, Malaysia was the most likely country of origin for TMUV, while Shandong Province was the earliest province of origin in China. This study has important implications for understanding TMUV and provides suggestions for its prevention and control.
SARS-CoV-2 Accessory Protein ORF8 Decreases Antibody-Dependent Cellular Cytotoxicity
Authors: Beaudoin-Bussières Guillaume , Arduini Ariana , Bourassa Catherine , Medjahed Halima , Gendron-Lepage Gabrielle , Richard Jonathan , Pan Qinghua , Wang Zhen , Liang Chen , Finzi Andrés
Published: June 2022

Viruses use many different strategies to evade host immune responses. In the case of SARS-CoV-2, its Spike mutates rapidly to escape from neutralizing antibodies. In addition to this strategy, ORF8, a small accessory protein encoded by SARS-CoV-2, helps immune evasion by reducing the susceptibility of SARS-CoV-2-infected cells to the cytotoxic CD8+ T cell response. Interestingly, among all accessory proteins, ORF8 is rapidly evolving and a deletion in this protein has been linked to milder disease. Here, we studied the effect of ORF8 on peripheral blood mononuclear cells (PBMC). Specifically, we found that ORF8 can bind monocytes as well as NK cells. Strikingly, ORF8 binds CD16a (FcγRIIIA) with nanomolar affinity and decreases the overall level of CD16 at the surface of monocytes and, to a lesser extent, NK cells. This decrease significantly reduces the capacity of PBMCs and particularly monocytes to mediate antibody-dependent cellular cytotoxicity (ADCC). Overall, our data identifies a new immune-evasion activity used by SARS-CoV-2 to escape humoral responses.
Sex Differences in COVID-19 Hospitalization and Hospital Mortality among Patients with COPD in Spain: A Retrospective Cohort Study
Authors: de Miguel-Diez Javier , Lopez-de-Andres Ana , Jimenez-Garcia Rodrigo , de Miguel-Yanes Jose M. , Hernández-Barrera Valentin , Carabantes-Alarcon David , Zamorano-Leon Jose J. , Lopez-Herranz Marta , Omaña-Palanco Ricardo
Published: June 2022

(1) Background: We aimed to assess the effect of COPD in the incidence of hospital admissions for COVID-19 and on the in-hospital mortality (IHM) according to sex. (2) Methods: We used national hospital discharge data to select persons aged ≥40 years admitted to a hospital with a diagnosis of COVID-19 in 2020 in Spain. (3) Results: The study population included 218,301 patients. Age-adjusted incidence rates of COVID-19 hospitalizations for men with and without COPD were 10.66 and 9.27 per 1000 persons, respectively (IRR 1.14; 95% CI 1.08–1.20; p < 0.001). The IHM was higher in men than in women regardless of the history of COPD. The COPD was associated with higher IHM among women (OR 1.09; 95% CI 1.01–1.22) but not among men. The COPD men had a 25% higher risk of dying in the hospital with COVID-19 than women with COPD (OR 1.25, 95% CI 1.1–1.42). (4) Conclusions: Sex differences seem to exist in the effect of COPD among patients suffering COVID-19. The history of COPD increased the risk of hospitalization among men but not among women, and COPD was only identified as a risk factor for IHM among women. In any case, we observed that COPD men had a higher mortality than COPD women. Understanding the mechanisms underlying these sex differences could help predict the patient outcomes and inform clinical decision making to facilitate early treatment and disposition decisions.