bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiobjective Design Optimization of Lightweight Gears
Authors: Cosco Francesco , Adduci Rocco , Muzzi Leonardo , Rezayat Ali , Mundo Domenico
Published: September 2022

Lightweight gears have the potential to substantially contribute to the green economy demands. However, gear lightweighting is a challenging problem where various factors, such as the definition of the optimization problem and the parameterization of the design space, must be handled to achieve design targets and meet performance criteria. Recent advances in FE-based contact analysis have demonstrated that using hybrid FE–analytical gear contact models can offer a good compromise between computational costs and predictive accuracy. This paper exploits these enabling methodologies in a fully automated process, efficiently and reliably achieving an optimal lightweight gear design. The proposed methodology is demonstrated by prototyping a software architecture that combines commercial solutions and ad hoc procedures. The feasibility and validity of the proposed methodology are assessed, considering the multiobjective optimization of a transmission consisting of a pair of helical gears.
Effect of Machining Trajectory on Grinding Force of Complex-Shaped Stone by Robotic Manipulator
Authors: Yin Fangchen , Wu Shatong , Huang Hui , Cui Changcai , Ji Qingzhi
Published: September 2022

Complex-shaped stone products (CSSPs) have become stone products with high added economic value due to their complex overall shape, outline structure, and various curved surfaces. Recently, robotic manipulators—pieces of intelligent machining equipment—equipped with grinding end-effectors have significantly replaced handheld equipment and have also shown significant advantages in grinding efficiency and modeling flexibility. However, natural stone generally has the characteristics of poor craftsmanship and low rigidity. Improper control of the grinding force while grinding can easily cause the stone blank to break and scrap the workpiece. Therefore, in this study, we consider CSSPs and examine their surface curvature characteristics. The matching relationship between surface characteristics and machining trajectory is studied through simulation. Furthermore, the grinding force fluctuation in the finishing is optimized, and the optimal machining trajectory of the finishing process is determined to improve the surface profile error. Then, the simulation reliability is verified through experiments. The results show a 52.8% reduction in the grinding force fluctuation and a 36.9% reduction in the surface profile error after machining.
Dynamics of a Reduced System Connected to the Investigation of an Infinite Network of Identical Theta Neurons
Authors: Bîrdac Lavinia , Kaslik Eva , Mureşan Raluca
Published: September 2022

We consider an infinite network of identical theta neurons, all-to-all coupled by instantaneous synapses. Using the Watanabe–Strogatz Ansatz, the mathematical model of this infinite network is reduced to a two-dimensional system of differential equations. We determine the number of equilibria of this reduced system with respect to two characteristic parameters. Furthermore, we discuss the stability properties of each equilibrium and the possible bifurcations that may take place. As a result, the occurrence of exotic higher codimension bifurcations involving a degenerate center is also unveiled. Numerical results are also presented to illustrate complex dynamic behaviour in the reduced system.
Runge–Kutta Embedded Methods of Orders 8(7) for Use in Quadruple Precision Computations
Authors: Kovalnogov Vladislav , Fedorov Ruslan , Karpukhina Tamara , Simos Theodore , Tsitouras Charalampos
Published: September 2022

High algebraic order Runge–Kutta embedded methods are commonly used when stringent tolerances are demanded. Traditionally, various criteria are satisfied while constructing these methods for application in double precision arithmetic. Firstly we try to keep the magnitude of the coefficients low, otherwise we may experience loss of accuracy; however, when working in quadruple precision we may admit larger coefficients. Then we are able to construct embedded methods of orders eight and seven (i.e., pairs of methods) with even smaller truncation errors. A new derived pair, as expected, is performing better than state-of-the-art pairs in a set of relevant problems.
Modelling the Potential Impact of Stigma on the Transmission Dynamics of COVID-19 in South Africa
Authors: Gatyeni Siphokazi Princess , Chirove Faraimunashe , Nyabadza Farai
Published: September 2022

The COVID-19 pandemic continues to be a problem in South Africa. Individuals affected and infected by the disease suffer from stigma resulting in increased COVID-19 infections. In this paper, we developed a mathematical model to assess the effects of stigma on COVID-19 in South Africa, using low, moderate, and high stigma regimes in the population. The mathematical model was analysed and the basic reproduction number, R0, of the COVID-19 model with stigma was determined. The model was then fitted to data of the four COVID-19 waves for the new daily infected cases, and the estimated parameter values from different waves are presented. The effects of stigma on COVID-19 waves were examined using the four stigma regimes (high, moderate, low, and stigma-free regimes). Our results revealed that stigma is instrumental in the increase in the number of COVID-19 infections. It is also a significant contributor to sustaining COVID-19 in the population and probably in other infectious diseases such as HIV/AIDS and sexually transmitted diseases. The results obtained can influence policy directions with respect to stigma and its impact on the transmission dynamics of diseases.
IN-ME Position Error Compensation Algorithm for the Near-Field Beamforming of UAVs
Authors: Zhang Yinan , Wang Guangxue , Leng Yi , Yu Guowen , Peng Shirui
Published: September 2022

The target of an unmanned aerial vehicle swarm will present near-field characteristics when it is integrated as an array, and the existence of the unmanned aerial vehicle swarm motion error will greatly deteriorate the beam pattern formed by the array. To solve these problems, a near-field array beamforming model with array element position error is constructed, and the Taylor expansion of the phase difference function is used to approximately simplify the model. The improved Newton maximum entropy algorithm is proposed to estimate and compensate for the phase errors. The maximum entropy objective function is established, and the Newton iterative algorithm is used to estimate the phase error iteratively. To select the proper Newton iteration initial value, based on a single reference source signal, the initial value of the phase error is estimated through the phase gradient information of the received array signal. Beamforming is carried out after phase error compensation regarding the array. In order to assess the mismatch of the phase error compensation function based on the proposed method, when the beam is scanning, the effectively compensated spatial area of the array beamforming is divided, which lays a foundation for subsequent spatial region division and unmanned aerial vehicle swarm path planning. The simulation results show that the beam formed by the method proposed in this paper has a lower sidelobe level, and as the signal-to-noise ratio changes, the robustness of the proposed method is better validated. The proposed algorithm can effectively suppress the adverse influence of array element position error on array beamforming, and when the beam is scanning, the effectively compensated area of the phase error compensation function is divided, based on the proposed method.
Positive Radially Symmetric Entire Solutions of p-k-Hessian Equations and Systems
Authors: Fan Wei , Dai Limei , Wang Bo
Published: September 2022

In this paper, we discuss the existence of positive radially symmetric entire solutions of the p-k-Hessian equation σk1kλDi|Du|p−2Dju=α1k(|x|)f(u), and the general p-k-Hessian system σk1kλDi|Du|p−2Dju=α1k(|x|)f1(v)f2(u), σk1kλDi|Dv|p−2Djv=β1k(|x|)g1(u)g2(v).
Comparative Study on Lower-Middle-, Upper-Middle-, and Higher-Income Economies of ASEAN for Fiscal and Current Account Deficits: A Panel Econometric Analysis
Authors: Marimuthu Maran , Khan Hanana , Bangash Romana
Published: September 2022

For the last three decades, ASEAN has been facing a persistent fiscal deficit. However, the impact of fiscal deficit on the current account deficit in the sub-groups of ASEAN is still unknown. This study aims to investigate the impact of fiscal deficit on current account deficit and their relationship among the three sub-groups of ASEAN which are based on gross national income (GNI), i.e., lower-middle-, upper-middle-, and higher-income countries. The analysis covers the panel data collected over the span of the last three decades (1990–2020) for ten Southeast Asian nations (ASEAN). The analyses incorporate the panel methodology for data analysis such as panel unit root for checking data stationarity, cointegration testing, panel autoregressive distributed lag (PARDL) for short- and long-run analysis, cointegration regression (fully modified and dynamic ordinary least squares) for significance, the panel Dumitrescu and Hurlin Granger causality test for examining causal relationships in tested variables, and stability diagnostics and CUMSUM and CUSUMSQ techniques for structural breaks and coefficient stability in the model. In lower-middle-income economies (LMIE), results indicate the existence of a unidirectional causal relationship from the current account deficit (CAD) to the fiscal deficit (FD), suggesting a reverse causal relationship from CAD to FD. In the long run, FD does not significantly induce CAD, while real interest rate (RIR) and exchange rate (EXC) influence CAD. In upper-middle-income economies (UMIE), results specify that there is no causality between FD and CAD. The RIR, EXC, and FD are significant to CAD in the long run. In higher-income economies (HIE), RIR and FD have an influence on CAD in the long run period. Moreover, from CAD to FD, a unidirectional causal association exists, and likewise for LMIE. This is a reverse causal relationship from CAD to the FD, supporting the current account targeting hypothesis (CATH) in both the LMIE and HIE groups. This study recommends that the LMIE and HIE groups can use the fiscal deficit as a tool to eliminate the unfavorable current account position. Policymakers can target EXC and RIR to stabilize CAD in long run. In UMIE and HIE, policymakers must consider FD alarming, as it can induce CAD in the long run. The RIR can be the targeted factor in the sub-groups of ASEAN.
Feed-Forward Neural Networks Training with Hybrid Taguchi Vortex Search Algorithm for Transmission Line Fault Classification
Authors: Coban Melih , Tezcan Suleyman Sungur
Published: September 2022

In this study, the hybrid Taguchi vortex search (HTVS) algorithm, which exhibits a rapid convergence rate and avoids local optima, is employed as a new training algorithm for feed-forward neural networks (FNNs) and its performance was analyzed by comparing it with the vortex search (VS) algorithm, the particle swarm optimization (PSO) algorithm, the gravitational search algorithm (GSA) and the hybrid PSOGSA algorithm. The HTVS-based FNN (FNNHTVS) algorithm was applied to three datasets (iris classification, wine recognition and seed classification) taken from the UCI database (the machine learning repository of the University of California at Irvine) and to the 3-bit parity problem. The obtained statistical results were recorded for comparison. Then, the proposed algorithm was used for fault classification on transmission lines. A dataset was created using 735 kV, 60 Hz, 100 km transmission lines for different fault types, fault locations, fault resistance values and fault inception angles. The FNNHTVS algorithm was applied to this dataset and its performance was tested in comparison with that of other classifiers. The results indicated that the performance of the FNNHTVS algorithm was at least as successful as that of the other comparison algorithms. It has been shown that the FNN model trained with HTVS can be used as a capable alternative algorithm for the solution of classification problems.
Heuristic Approaches Based on Modified Three-Parameter Model for Inverse Acoustic Characterisation of Sintered Metal Fibre Materials
Authors: Zhao Tianfei , Pan Baorui , Song Xiang , Sui Dan , Xiao Heye , Zhou Jie
Published: September 2022

Modelling of sound propagation in porous media generally requires the knowledge of several transport properties of the materials. In this study, a three-parameter analytical model that links microstructure properties of sintered metal fibre materials and non-acoustical parameters of the JCAL model is used and modified, and two heuristic approaches based on the established model for inverse acoustic characterisation of fibrous metal felts are developed. The geometric microstructure of sintered fibrous metals is simplified to derive the relationship between pores and fibre diameters. The new set of transport parameters in the modified three-parameter model can cover two controllable parameters during the fabrication process of fibrous metals. With two known transport parameters, six sintered specimens are characterised using a deterministic algorithm, and a satisfactory result is achieved in fitting the normalised surface impedance measured by an acoustic measurement system. Moreover, the forward evaluation shows that our modified three-parameter theoretical model is capable of yielding accurate results for the sintered metal fibre materials. A numerical investigation of the complete inverse acoustic characterisation of fibrous metals by a global non-deterministic algorithm indicates that inversion from two porous material properties is preferable to the normalised surface impedance.
Geometrical Theory of Analytic Functions
Authors: Oros Georgia Irina
Published: September 2022

This Special Issue, devoted to the topic of the “Geometric Theory of Analytic Functions”, aims to bring together the newest research achievements of scholars studying the complex-valued functions of one variable [...]
Stunting as a Risk Factor for Asthma: The Role of Vitamin D, Leptin, IL-4, and CD23+
Authors: Sapartini Gartika , Wong Gary W.K. , Indrati Agnes Rengga , Kartasasmita Cissy B. , Setiabudiawan Budi
Published: September 2022

Stunting, which results from chronic malnutrition, is common in children from low- and middle-income countries. Several studies have reported an association between obesity and asthma. However, only a handful of studies have identified stunting as a significant risk factor for wheezing, a symptom of asthma, although the underlying mechanism remains unclear. This article aimed to review possible mechanisms underlying asthma in stunted children. Overall, changes in diet or nutritional status and deficiencies in certain nutrients, such as vitamin D, can increase the risk of developing asthma. Vitamin D deficiency can cause linear growth disorders such as stunting in children, with lower levels of 25(OH)D found in underweight and stunted children. Stunted children show a decreased lean body mass, which affects lung growth and function. Low leptin levels during undernutrition cause a Th1–Th2 imbalance toward Th2, resulting in increased interleukin (IL)-4 cytokine production and total immunoglobulin E (IgE). Studies in stunted underweight children have also found an increase in the proportion of the total number of B cells with low-affinity IgE receptors (CD23+). CD23+ plays an important role in allergen presentation that is facilitated by IgE to T cells and strongly activates allergen-specific T cells and the secretion of Th2-driving cytokines. Stunted children present with low vitamin D and leptin levels, impaired lung growth, decreased lung function, and increased IL-4 and CD23+ levels. All of these factors may be considered consequential in asthma in stunted children.
Antidiabetics, Anthelmintics, Statins, and Beta-Blockers as Co-Adjuvant Drugs in Cancer Therapy
Authors: Gales Laurentia , Forsea Leyla , Mitrea Diana , Stefanica Irina , Stanculescu Irina , Mitrica Radu , Georgescu Mihai , Trifanescu Oana , Anghel Rodica , Serbanescu Luiza
Published: September 2022

Over the last years, repurposed agents have provided growing evidence of fast implementation in oncology treatment such as certain antimalarial, anthelmintic, antibiotics, anti-inflammatory, antihypertensive, antihyperlipidemic, antidiabetic agents. In this study, the four agents of choice were present in our patients’ daily treatment for nonmalignant-associated pathology and have known, light toxicity profiles. It is quite common for a given patient’s daily administration schedule to include two or three of these drugs for the duration of their treatment. We chose to review the latest literature concerning metformin, employed as a first-line treatment for type 2 diabetes; mebendazole, as an anthelmintic; atorvastatin, as a cholesterol-lowering drug; propranolol, used in cardiovascular diseases as a nonspecific inhibitor of beta-1 and beta-2 adrenergic receptors. At the same time, certain key action mechanisms make them feasible antitumor agents such as for mitochondrial ETC inhibition, activation of the enzyme adenosine monophosphate-activated protein kinase, amelioration of endogenous hyperinsulinemia, inhibition of selective tyrosine kinases (i.e., VEGFR2, TNIK, and BRAF), and mevalonate pathway inhibition. Despite the abundance of results from in vitro and in vivo studies, the only solid data from randomized clinical trials confirm metformin-related oncological benefits for only a small subset of nondiabetic patients with HER2-positive breast cancer and early-stage colorectal cancer. At the same time, clinical studies confirm metformin-related detrimental/lack of an effect for lung, breast, prostate cancer, and glioblastoma. For atorvastatin we see a clinical oncological benefit in patients and head and neck cancer, with a trend towards radioprotection of critical structures, thus supporting the role of atorvastatin as a promising agent for concomitant association with radiotherapy. Propranolol-related increased outcomes were seen in clinical studies in patients with melanoma, breast cancer, and sarcoma.
Effect of Dentin-Disinfection Chemicals on Shear Bond Strength and Microhardness of Resin-Infiltrated Human Dentin in Different Adhesive Protocols
Authors: Haralur Satheesh , Alqahtani Mohammed , Alqahtani Roaa , Shabab Rayan , Hummadi Khalid
Published: September 2022

Background and Objectives: Bacteria and its remnants beneath the restorations predispose the tooth to secondary caries and pulpal pathology. Hence, various chemical antibacterial agents are suggested to disinfect the prepared tooth structure before the definitive restorative procedure. This study aimed to investigate the effects of chemical disinfectant solutions on the micro-shear bond strength (µSBS) and microhardness of total-etch and self-etch resin-infiltrated human dentin. Materials and Methods: 100 caries-free intact permanent third molar teeth were vertically sectioned into the buccal and lingual half. All these specimens were mounted on acrylic resin and underlying dentin surfaces were exposed by grinding. Samples were randomly divided into five groups [n = 20] following total-etch and self-etch adhesive protocol. Teeth samples were divided according to surface treatment, as Group I (Control-CNT), Group II (2% chlorhexidine-CHX), Group III (5.25% sodium hypochlorite-NaOCl), Group IV (17% ethylenediaminetetraacetate acid—EDTA) and Group V (10% povidone iodine-PVI). A randomly selected 10 samples from each subgroup were used for µSBS and microhardness tests. After surface treatment and bonding procedure, nono-hybrid composite cylinders with a 3-mm diameter and 2-mm height were directly cured over the dentin substrate. The samples for µSBS were subjected to 5000 thermocycles and tested using a universal testing machine. Microhardness was assessed using a micro-indenter instrument, data were statistically analyzed using a one-way analysis of variance and Tukey HSD tests at p < 0.05. Results: Amongst the chemical disinfectant assessed, 2% CHX did not affect µSBS and produced a marginal reduction in dentin microhardness compared to the control group. The 5.25% NaOCl and 17% EDTA significantly compromised the microhardness of the dentin substrate. Meanwhile, 10% PVI surface treatment resulted in a substantial reduction in µSBS between composite and dentin. Conclusions: CHX with preservation of bonding to dentin and insignificant negative effect on dentin microhardness is a safe option for tooth disinfection.
Fecal Bile Acids and Neutral Sterols Are Associated with Latent Microbial Subgroups in the Human Gut
Authors: Breuninger Taylor A. , Wawro Nina , Freuer Dennis , Reitmeier Sandra , Artati Anna , Grallert Harald , Adamski Jerzy , Meisinger Christa , Peters Annette , Haller Dirk , Linseisen Jakob
Published: September 2022

Bile acids, neutral sterols, and the gut microbiome are intricately intertwined and each affects human health and metabolism. However, much is still unknown about this relationship. This analysis included 1280 participants of the KORA FF4 study. Fecal metabolites (primary and secondary bile acids, plant and animal sterols) were analyzed using a metabolomics approach. Dirichlet regression models were used to evaluate associations between the metabolites and twenty microbial subgroups that were previously identified using latent Dirichlet allocation. Significant associations were identified between 12 of 17 primary and secondary bile acids and several of the microbial subgroups. Three subgroups showed largely positive significant associations with bile acids, and six subgroups showed mostly inverse associations with fecal bile acids. We identified a trend where microbial subgroups that were previously associated with “healthy” factors were here inversely associated with fecal bile acid levels. Conversely, subgroups that were previously associated with “unhealthy” factors were positively associated with fecal bile acid levels. These results indicate that further research is necessary regarding bile acids and microbiota composition, particularly in relation to metabolic health.
Glucocorticoid-Induced Hyperinsulinism in a Preterm Neonate with Inherited ABCC8 Variant
Authors: Motte-Signoret Emmanuelle , Saint-Martin Cécile , Bellané-Chantelot Christine , Portha Bernard , Boileau Pascal
Published: September 2022

Glucose homeostasis is a real challenge for extremely preterm infants (EPIs) who have both limited substrate availability and immature glucose metabolism regulation. In the first days of life, EPIs frequently develop transient glucose intolerance, which has a complex pathophysiology that associates unregulated gluconeogenesis, immature insulin secretion, and peripheral insulin resistance. In this population, glucocorticoid therapy is frequently administrated to prevent severe bronchopulmonary dysplasia. During this treatment, glucose intolerance classically increases and may lead to hyperglycemia. We report a case of neonatal hypoglycemia that was concomitant to a glucocorticoids administration, and that led to a congenital hyperinsulinism diagnosis in an EPI with a heterozygous ABCC8 variant. The variant was inherited from his mother, who had developed monogenic onset diabetes of the youth (MODY) at the age of 23. ABCC8 encodes a beta-cell potassium channel unit and causes congenital hyperinsulinism or MODY depending on the mutation location. Moreover, some mutations have been observed in the same patient to cause both hyperinsulinism in infancy and MODY in adulthood. In our case, the baby showed repeated and severe hypoglycemias, which were undoubtedly time-associated with the betamethasone intravenous administration. This hyperinsulinism was transient, and the infant has not yet developed diabetes at three years of age. We take the opportunity presented by this unusual clinical presentation to provide a review of the literature, suggesting new insights regarding the pathophysiology of the beta-pancreatic cells’ insulin secretion: glucocorticoids may potentiate basal insulin secretion in patients with ABCC8 mutation.
High-Efficiency Copper Removal by Nitrogen Plasma-Assisted Picosecond Laser Processing
Authors: Li Yunfan , Guo Xuanqi , Wang Shuai , Zhang Shizhuo , Zhao Yilin , Guo Dingyi , Zhang Chen , Liu Sheng , Cheng Gary J. , Liu Feng
Published: September 2022

Copper (Cu) removal efficiency is a key parameter in the processing of Cu-based electronic devices. Herein, a nitrogen plasma-assisted picosecond (ps) laser process for Cu removal is presented. Based on the cleaning and activation effect of nitrogen plasma on the surface of Cu film in ps-laser ablation, the removal efficiency can be significantly improved. Theoretically, the interaction mechanism between Cu and the ps-laser under the action of the plasma flow field is investigated by the dual temperature model (TTM) and finite element analysis (FEA). Meanwhile, the experimental results show that the angle of the plasma flow significantly affects the laser ablation of Cu. Small-angle plasma helps to improve the ps-laser processing precision of Cu, while large-angle plasma can effectively improve the ps-laser processing efficiency of Cu. Under the laser fluence of 2.69 J/cm2, the removal depth of the Cu film by a 30° plasma-assisted ps-laser is 148% higher than that by the non-plasma-assisted ps-laser, which indicates the application potential of nitrogen plasma in improving the laser ablation process.
The Effect of Heavy Metals on Microbial Communities in Industrial Soil in the Area of Piekary Śląskie and Bukowno (Poland)
Authors: Jarosławiecka Anna Katarzyna , Piotrowska-Seget Zofia
Published: September 2022

The aim of this study was to determine the activity and structure of microbial communities in soils contaminated with heavy metals (HMs). To achieve this goal, soil samples were taken from two contaminated sites (i.e., Piekary Śląskie and Bukowno) in Poland. A wide range of methods were applied, including: total and metal-tolerant culturable bacteria enumeration; microbial community structure analysis using the phospholipid fatty acid method (PLFA); denaturing gradient gel electrophoresis (PCR-DGGE); and metabolic activity using BIOLOG and EcoPlateTM. Our studies showed that HMs negatively affected microbial community structure and activity in polluted soils. Apart from the contamination with HMs, other soil parameters like soil pH and water also impacted microbial community structure and growth. Metal-tolerant bacterial strains were isolated, identified and tested for presence of genes encoding HM tolerance using the polymerase chain reaction (PCR) methodology. Contamination with HMs in the tested areas was found to lead to development of metallotolerant bacteria with multiple tolerances toward Zn, Ni, Cd and Cu. Different genes (e.g., czcA, cadA and nccA) encoding HM efflux pumps were detected within isolated bacteria. Culturable bacteria isolated belonged to Proteobacteria, Actinobacteria and Bacteroidetes genera. Among non-culturable bacteria in soil samples, a significant fraction of the total bacteria and phyla, such as Gemmatimonadetes and Acidobacteria, were found to be present in all studied soils. In addition, bacteria of the Chloroflexi genus was present in soil samples from Piekary Śląskie, while bacteria of the Firmicutes genus were found in soil samples from Bukowno.
The Metabolic Potential of Endophytic Actinobacteria Associated with Medicinal Plant Thymus roseus as a Plant-Growth Stimulator
Authors: Mohamad Osama Abdalla Abdelshafy , Liu Yong-Hong , Huang Yin , Li Li , Ma Jin-Biao , Egamberdieva Dilfuza , Gao Lei , Fang Bao-Zhu , Hatab Shaimaa , Jiang Hong-Chen , Li Wen-Jun
Published: September 2022

Bio-fertilizer practice considers not only economical but also environmentally friendly, sustainable agriculture. Endophytes can play important beneficiary roles in plant development, directly, indirectly, or synergistically. In this study, the majority of our endophytic actinobacteria were able to possess direct plant growth-promoting (PGP) traits, including auxin (88%), ammonia (96%), siderophore production (94%), and phosphate solubilization (24%), along with cell-wall degrading enzymes such as protease (75%), cellulase (81%), lipase (81%), and chitinase (18%). About 45% of tested strains have an inhibitory effect on the phytopathogen Fusarium oxysporum, followed by 26% for Verticillium dahlia. Overall, our results showed that strains XIEG63 and XIEG55 were the potent strains with various PGP traits that caused a higher significant increase (p ≤ 0.05) in length and biomass in the aerial part and roots of tomato and cotton, compared to the uninoculated plants. Our data showed that the greatest inhibition percentages of two phytopathogens were achieved due to treatment with strains XIEG05, XIEG07, XIEG45, and XIEG51. The GC-MS analysis showed that most of the compounds were mainly alkanes, fatty acid esters, phenols, alkenes, and aromatic chemicals and have been reported to have antifungal activity. Our investigation emphasizes that endophytic actinobacteria associated with medicinal plants might help reduce the use of chemical fertilization and potentially lead to increased agricultural productivity and sustainability.
Cumulative Risk Assessment of Soil-Crop Potentially Toxic Elements Accumulation under Two Distinct Pollution Systems
Authors: Lu Weihong , Liu Juan , Wang Yaofang , Zhang Naiming , Ren Lijuan , Bao Li
Published: September 2022

High geological background and human activities are the two major pollution sources for soil potentially toxic elements (PTEs) accumulation around the world. Mining is the prime human activity that poses a serious threat to the farmland’s ecosystem safety. This study assesses the farmland safety in the typical high geological background area and the superimposed area of high background-mining activity in eastern Yunnan in China by systematic analysis of the accumulation and risk characteristics of seven PTEs such as arsenic (As), mercury (Hg), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), and chromium (Cr). Furthermore, we used Cd as the characteristic element to establish a relationship model between crop PTEs accumulation and the physical and chemical characteristics of the soil. We find that in the farmland soil from the superimposed area, the accumulation point over-standard rate of seven PTEs is higher than in the typical high geological background area. The accumulation of Pb, Cd, Cu, and Zn is related to frequent man-made mining activities. The bioavailability relationship model, using Cd as the soil-crop characteristic element, reveals that only in the crops (cereals, vegetables) of the high geological background area; the Cd bio-concentration factor significantly correlate with the physical and chemical properties of the soil. This suggests that the PTEs contaminated farmland in high geological background areas can be concomitantly restored during usage by adjusting the soil’s physical and chemical properties, while in the superimposed area, the farmland area needs prior restoration by removing man-made mining activities.
Multi-Step Gold Refinement and Collection Using Bi-Minerals in the Laozuoshan Gold Deposit, NE China
Authors: Meng Lin , Huang Fei , Gao Wenyuan , Gao Rongzhen , Zhao Fude , Zhou Yiran , Li Yongli
Published: September 2022

Gold and Bi-bearing parageneses are pivotal to understanding gold concentration and deposition processes. The large-scale Laozuoshan gold deposit is located in the Jiamusi Block, northeastern China, and has experienced complex mineralization processes with abundant gold and Bi-bearing minerals. However, the relationship between Bi-minerals and gold is unclear, preventing our understanding of the gold enrichment and precipitation mechanism in the Laozuoshan gold deposit. Optical microscope and SEM results show three stages of gold mineralization: pyrrhotite (Po-1) + arsenopyrite (Apy-1) + Bi-bearing minerals (Bis-1) + Au-1; arsenopyrite (Apy-2) + chlorite + Bi-bearing minerals (Bis-2) + Au-2; and arsenopyrite (Apy-3) + graphite + Bi-bearing minerals (Bis-3) + Au-3. The abundant amount of gold (Au-1~Au-3) is associated with Bi-bearing minerals (Bis-1~Bis-3), which coexist as inclusions and fill in fractures in these minerals. The mineral assemblages of arsenopyrite, Bi-minerals, and gold exhibit a clear As-Bi-Au mineralogy in the ores, and the ternary diagram of the chemical compositions of the Bi-minerals shows that Bi-minerals all fall in reducing regions, indicating that Bi-minerals are precipitated under reducing conditions. The gold compositions demonstrate a positive correlation (R2 = 0.58) between Au and Bi. Consequently, we propose that the gold experienced the ore-forming fluids concentration and further Bi-melts scavenging for the Laozuoshan gold deposit mineralization. The Bi collector model is essential in interpreting the high-grade gold in the Laozuoshan gold deposit, indicating that the geochemical anomalies observed with bismuth may be a critical potential exploration target for the high-grade gold deposits in the Jiamusi Block.
Sulfate and Freeze-Thaw Resistance of Porous Geopolymer Based on Waste Clay and Aluminum Salt Slag
Authors: Bumanis Girts , Bajare Diana , Korjakins Aleksandrs , Vaičiukynienė Danutė
Published: September 2022

The search for efficient waste source precursors for geopolymer production is active in scientific society. The feasibility of using calcined kaolin clay and fly ash as suitable precursors for the production of geopolymers is widely described and acknowledged. The availability and energy input required to produce such precursors hinders their competing with traditional binders, however. Therefore, new by-product source precursors are sought in different industries. In this research, three industrial origin secondary raw materials are examined as precursors for the production of porous geopolymers. Calcined illite or kaolin clay in combination with salt cake from the aluminium scrap recycling industry after alkali activation gives lightweight material from 540–675 kg/m3. A comparison of the two precursors was made, and the physical and mechanical properties were determined. Freeze-thaw resistance and sulfate attack were used to characterize durability. Results indicate the role of waste clay type and salt cake content on geopolymer properties as materials with similar appearance performed differently. The results show that metakaolin based geopolymers outperformed red clay based geopolymers and they can withstand from 25 to 50 freeze-thaw cycles with strength loss from 10 to 65%. Sulfate attack showed significant strength loss for red clay based geopolymers after 61 days of soaking time in contrast to metakaolin based geopolymers.
Interfacial Characterization of Polypyrrole/AuNP Composites towards Electrocatalysis of Ascorbic Acid Oxidation
Authors: Pesqueira Camila , Hryniewicz Bruna M. , Bach-Toledo Larissa , Tenório Luciane Novaes , Marchesi Luís F. , Mazon Talita , Vidotti Marcio
Published: September 2022

Polypyrrole (PPy) is an interesting conducting polymer due to its good environmental stability, high conductivity, and biocompatibility. The association between PPy and metallic nanoparticles has been widely studied since it enhances electrochemical properties. In this context, gold ions are reduced to gold nanoparticles (AuNPs) directly on the polymer surface as PPy can be oxidized to an overoxidized state. This work proposes the PPy electrochemical synthesis followed by the direct reduction of gold on its surface in a fast reaction. The modified electrodes were characterized by electronic microscopic and infrared spectroscopy. The effect of reduction time on the electrochemical properties was evaluated by the electrocatalytic properties of the obtained material from the oxidation of ascorbic acid (AA) and electrochemical impedance spectroscopy studies. The presence of AuNPs improved the AA electrocatalysis by reducing oxidation potential and lowering charge transfer resistance. EIS data were fitted using a transmission line model. The results indicated an increase in the electronic transport of the polymeric film in the presence of AuNPs. However, PPy overoxidation occurs when the AuNPs’ deposition is higher than 30 s. In PPy/AuNPs 15 s, smaller and less agglomerated particles were formed with fewer PPy overoxidized, confirming the observed electrocatalytic behavior.
Exploring the Palynological, Chemical, and Bioactive Properties of Non-Studied Bee Pollen and Honey from Morocco
Authors: Bakour Meryem , Laaroussi Hassan , Ferreira-Santos Pedro , Genisheva Zlatina , Ousaaid Driss , Teixeira José Antonio , Lyoussi Badiaa
Published: September 2022

Bee products are known for their beneficial properties widely used in complementary medicine. This study aims to unveil the physicochemical, nutritional value, and phenolic profile of bee pollen and honey collected from Boulemane–Morocco, and to evaluate their antioxidant and antihyperglycemic activity. The results indicate that Citrus aurantium pollen grains were the majority pollen in both samples. Bee pollen was richer in proteins than honey while the inverse was observed for carbohydrate content. Potassium and calcium were the predominant minerals in the studied samples. Seven similar phenolic compounds were found in honey and bee pollen. Three phenolic compounds were identified only in honey (catechin, caffeic acid, vanillic acid) and six phenolic compounds were identified only in bee pollen (hesperidin, cinnamic acid, apigenin, rutin, chlorogenic acid, kaempferol). Naringin is the predominant phenolic in honey while hesperidin is predominant in bee pollen. The results of bioactivities revealed that bee pollen exhibited stronger antioxidant activity and effective α-amylase and α-glycosidase inhibitory action. These bee products show interesting nutritional and bioactive capabilities due to their chemical constituents. These features may allow these bee products to be used in food formulation, as functional and bioactive ingredients, as well as the potential for the nutraceutical sector.
An Insight into Symmetrical Cyanine Dyes as Promising Selective Antiproliferative Agents in Caco-2 Colorectal Cancer Cells
Authors: Serrano João L. , Maia Ana , Santos Adriana O. , Lima Eurico , Reis Lucinda V. , Nunes Maria J. , Boto Renato E. F. , Silvestre Samuel , Almeida Paulo
Published: September 2022

Cancer remains one of the diseases with the highest worldwide incidence. Several cytotoxic approaches have been used over the years to overcome this public health threat, such as chemotherapy, radiotherapy, and photodynamic therapy (PDT). Cyanine dyes are a class of compounds that have been extensively studied as PDT sensitisers; nevertheless, their antiproliferative potential in the absence of a light source has been scarcely explored. Herein, the synthesis of eighteen symmetric mono-, tri-, and heptamethine cyanine dyes and their evaluation as potential anticancer agents is described. The influences of the heterocyclic nature, counterion, and methine chain length on the antiproliferative effects and selectivities were analysed, and relevant structure–activity relationship data were gathered. The impact of light on the cytotoxic activity of the most promising dye was also assessed and discussed. Most of the monomethine and trimethine cyanine dyes under study demonstrated a high antiproliferative effect on human tumour cell lines of colorectal (Caco-2), breast (MCF-7), and prostate (PC-3) cancer at the initial screening (10 µM). However, concentration–viability curves showed higher potency and selectivity for the Caco-2 cell line. A monomethine cyanine dye derived from benzoxazole was the most promising compound (IC50 for Caco-2 = 0.67 µM and a selectivity index of 20.9 for Caco-2 versus normal human dermal fibroblasts (NHDF)) and led to Caco-2 cell cycle arrest at the G0/G1 phase. Complementary in silico studies predicted good intestinal absorption and oral bioavailability for this cyanine dye.
Silver Nanoparticles Conjugated with Colistin Enhanced the Antimicrobial Activity against Gram-Negative Bacteria
Authors: Muenraya Poowadon , Sawatdee Somchai , Srichana Teerapol , Atipairin Apichart
Published: September 2022

Colistin is a potent peptide antibiotic that is effective against Gram-negative bacteria. However, nephrotoxicity limited its clinical use. Silver nanoparticles (AgNPs) have gained attention as a potential antimicrobial agent and nanodrug carrier. The conjugation of antibiotics and AgNPs has been found to increase the activity and decrease drug toxicity. In this study, colistin was conjugated with AgNPs (Col-AgNPs), which was confirmed by Fourier-transform infrared (FT-IR) and energy-dispersive X-ray (EDX) spectra. The optimized Col-AgNPs had the proper characteristics, including spherical shape, monodispersity, nanosized particle, high surface charge, and good stability. The powder X-ray diffraction (PXRD) pattern supported the crystallinity of Col-AgNPs and AgNPs. The drug loading of Col-AgNPs was 11.55 ± 0.93%. Col-AgNPs had higher activity against Gram-negative bacteria (Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa) than AgNPs and colistin. The mechanism of actions of Col-AgNPs involved membrane disruption and genomic DNA damage. The Col-AgNPs and AgNPs were biocompatible with human red blood cells and renal cells at concentrations up to 16 µg/mL. Interestingly, Col-AgNPs exhibited higher cell survival than AgNPs and colistin at 32 µg/mL. Our results revealed that the Col-AgNPs could enhance the antimicrobial activity and cell biocompatibility more than colistin and AgNPs.
Development of Yellow-to-Orange Photoluminescence Molecules Based on Alterations in the Donor Units of Fluorinated Tolanes
Authors: Yamada Shigeyuki , Kobayashi Kazuki , Konno Tsutomu
Published: September 2022

Since the aggregation-induced emission (AIE) phenomenon was first reported by Tang et al., much effort has been devoted to the development of solid-state luminescent molecules by chemists worldwide. Our group successfully developed fluorinated tolanes as novel compact π-conjugated luminophores with blue photoluminescence (PL) in the crystalline state. Moreover, we reported the yellow-green PL molecules based on their electron-density distributions. In the present study, we designed and synthesized fluorinated tolanes with various amine-based donors and evaluated their photophysical properties. The carbazole-substituted fluorinated tolane exhibited strong PL in the solution state, whereas piperidine- or phenothiazine-substituted fluorinated tolanes showed a dramatic decrease in PL efficiency. Notably, fluorinated tolanes with piperidine or phenothiazine substituents displayed yellow-to-orange PL in the crystalline state; this may have occurred because these tolanes exhibited tightly packed structures formed by intermolecular interactions, such as H···F hydrogen bonds, which suppressed the non-radiative deactivation process. Moreover, fluorinated tolanes with amine-based donors exhibited AIE characteristics. We believe that these yellow-to-orange solid PL molecules can contribute to the development of new solid luminescent materials.
Terpenoids from the Seeds of Toona sinensis and Their Ability to Attenuate High Glucose-Induced Oxidative Stress and Inflammation in Rat Glomerular Mesangial Cells
Authors: Chen Ying , Gao Hong , Liu Xiaoxiao , Zhou Jinyi , Jiang Yijin , Wang Feng , Wang Rongshen , Li Wanzhong
Published: September 2022

Toona sinensis (A. Juss.) Roem is an edible medicinal plant that belongs to the genus Toona within the Meliaceae family. It has been confirmed to display a wide variety of biological activities. During our continuous search for active constituents from the seeds of T. sinensis, two new acyclic diterpenoids (1–2), together with five known limonoid-type triterpenoids (3–7), five known apotirucallane-type triterpenoids (8–12), and three known cycloartane-type triterpenoids (13–15), were isolated and characterized. Their structures were identified based on extensive spectroscopic experiments, including nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectra (HR-ESI-MS), and electronic circular dichroism (ECD), as well as the comparison with those reported in the literature. We compared these findings to those reported in the literature. Compounds 5, 8, and 13–14 were isolated from the genus Toona, and compounds 11 and 15 were obtained from T. sinensis for the first time. The antidiabetic nephropathy effects of isolated compounds against high glucose-induced oxidative stress and inflammation in rat glomerular mesangial cells (GMCs) were assessed in vitro. The results showed that new compounds 1 and 2 could significantly increase the levels of Nrf-2/HO-1 and reduce the levels of NF-κB, TNF-α, and IL-6 at concentrations of 30 μM. These results suggest that compounds 1 and 2 might prevent the occurrence and development of diabetic nephropathy (DN) and facilitate the research and development of new antioxidant and anti-inflammatory drugs suitable for the prevention and treatment of DN.
Modeling Binary and Multicomponent Systems Containing Supercritical CO2 with Polyethylene Glycols and Compounds Relevant to the Biodiesel Production
Authors: Tsivintzelis Ioannis , Koutsou Georgios , Kontogeorgis Georgios M.
Published: September 2022

The CPA equation of state is applied to model binary, ternary, and multicomponent mixtures that contain CO2 with polyethylene glycols or compounds relevant to biodiesel production, such as glycerol and various triglycerides. Effort has been made to evaluate the model performance on correlating both the liquid and the vapor phase compositions, which is a demanding task, revealing the model’s and parameters’ limitations, due to the rather low concentrations of heavy compounds in the vapor phase. Initially the model’s binary parameters, which in all cases were temperature independent, were estimated using experimental data for binary systems. Those parameters were used to predict the phase behavior of supercritical CO2 containing ternary and multicomponent mixtures. Since no parameter was adjusted to ternary or multicomponent systems’ data, the reported CPA results for such mixtures are considered as pure predictions. This is the final part of a series of studies [Tsivintzelis et al. Fluid Phase Equilibria 430 (2016) 75–92 and 504 (2020) 112337] that complete the parameterization of the CPA equation of state for systems relevant to the biodiesel production, which allows the application of the model to multicomponent mixtures of the relevant processes.