bluuebunny/crossref_metadata_2025 huggingface dataset:
Limits of Land Capitalization and Its Economic Effects: Evidence from China
Authors: Cheng Jian , Zhao Jiangmeng , Zhu Daolin , Zhang Hui
Published: December 2021

Academic debates over the advantages and disadvantages of land capitalization are ongoing in China, but the fundamental issues behind the debate have not been adequately explored. We suggest that the core issue in land capitalization is the degree of capitalization. This study first theoretically deduced the existence of land capitalization limits; then, we used panel data from 35 key cities to conduct an empirical test, and finally we analyzed the current risk of excessive land capitalization in China. The results indicated that the mutual restriction of multiple land attributes determined the limits of land capitalization. Therefore, land capitalization has been categorized into two types—moderate and excessive—which produce different economic effects. The degree of land capitalization and real economic growth showed a significant inverted-U relationship, and the turning point appeared when the land capital value reached 2.5 times the land factor value. According to this threshold, we can infer that many key cities have been overcapitalized, which may lead to an economic recession and affect the growth prospects of China’s economy. Further analysis indicated that excessive land capitalization could be related to the unique Chinese style of decentralization. These conclusions have important policy implications for the reform of land marketization in countries undergoing economic transition. The goal of land reform is to allow the market mechanism to play a major role in land resource allocation, but the excessive capitalization of land must be prevented.
Forest Recreational Services in the Face of COVID-19 Pandemic Stress
Authors: Bamwesigye Dastan , Fialová Jitka , Kupec Petr , Łukaszkiewicz Jan , Fortuna-Antoszkiewicz Beata
Published: December 2021

Forest ecosystems provide numerous services and benefits to both humans and biodiversity. Similarly, urban forests services play a vital role by providing urban dwellers with recreational and leisure space, mental health relief, and meditation. In the wake of the COVID-19 epidemic, many people living in the urban areas could benefit from the forest and park recreational services to relieve psychological stress due to lockdown rules. The study examined existing literature simultaneously; however, very few studies have presented the relationships between forest services’ role on COVID-19 stress relief. Furthermore, we examined forest visitors’ frequency at the Training Forest Enterprise (TFE) Masaryk Forest Křtiny in the outskirts of Brno City in the Czech Republic. The study collected data using a TRAFx infrared trail counter before the pandemic (2015–2018) and during the COVID-19 period (2021). As in other studies of the subject, we observed an increasing trend in forest visits during the COVID-19 lockdown in 2021, compared to the same months before the pandemic in 2016 and 2017. We recommend further research to focus on scientific analysis of the relationship between forest ecosystem services and COVID-19 stress and mental health. Moreover, given the spike in visitors during the COVID-19 lockdown in 2021 in March and April, our data provide evidence regarding the role of nature for relieving stress and supporting mental and physical health. Policy, decision-makers and medical advisors could use such data and study to guide future lockdowns and pandemic situations regarding nature and forest recreational use and importance.
Optimization of Resistance Spot Welding with Inserted Strips via FEM and Response Surface Methodology
Authors: Zhao Yangyang , Wang Wurong , Wei Xicheng
Published: December 2021

Resistance spot welding (RSW) with inserted strips, a recent variant of traditional RSW, was usually adopted in joining thin gage steels to lower the temperature developed at the electrode surface and to extend electrode life. In order to understand the influencing mechanism how the inserted strips affect the heat transfer behavior and to optimize the selection of suitable strips, an approach integrated with FEM and response surface methodology (RSM) was employed. FEM results showed that the inserted strips would not only lead to earlier initiation of weld and bigger weld size in both diameter and thickness but also lower the electrode surface temperature. Based on FEM, uniform design and RSM were further employed to build a regression model between the strip properties (i.e., electrical/thermal conductivity, thickness) and the responses (i.e., electrode tip temperature, weld diameter, and temperature at strip/sheet interface). A graphical optimization was conducted to identify a preferable strip, and a Cu55Ni45 strip with a thickness of 0.12 mm was recommended for a 0.4 mm steel sheet.
High-Power Fiber Laser Welding of High-Strength AA7075-T6 Aluminum Alloy Welds for Mechanical Properties Research
Authors: El-Batahgy Abdel-Monem , Klimova-Korsmik Olga , Akhmetov Aleksandr , Turichin Gleb
Published: December 2021

The results disclosed that both the microstructure and mechanical properties of AA7075-T6 laser welds are considerably influenced by the heat input. In comparison with high heat input (arc welding), a smaller weld fusion zone with a finer dendrite arm spacing, limited loss of alloying elements, less intergranular segregation, and reduced residual tensile stress was obtained using low heat input. This resulted in a lower tendency of porosity and hot cracking, which improved the welded metal’s soundness. Subsequently, higher hardness as well as higher tensile strength for the welded joint was obtained with lower heat input. A welded joint with better mechanical properties and less mechanical discrepancy is important for better productivity. The implemented high-power fiber laser has enabled the production of a low heat input welded joint using a high welding speed, which is of considerable importance for minimizing not only the fusion zone size but also the deterioration of its properties. In other words, high-power fiber laser welding is a viable solution for recovering the mechanical properties of the high-strength AA 7075-T6 welds. These results are encouraging to build upon for further improvement of the mechanical properties to be comparable with the base metal.
Application of Machine Learning Model for the Prediction of Settling Velocity of Fine Sediments
Authors: Loh Wing Son , Chin Ren Jie , Ling Lloyd , Lai Sai Hin , Soo Eugene Zhen Xiang
Published: December 2021

Sedimentation management is one of the primary factors in achieving sustainable development of water resources. However, due to difficulties in conducting in-situ tests, and the complex nature of fine sediments, it remains a challenging task when dealing with issues related to settling velocity. Hence, the machine learning model appears as a suitable tool to predict the settling velocity of fine sediments in water bodies. In this study, three different machine learning-based models, namely, the radial basis function neural network (RBFNN), back propagation neural network (BPNN), and self-organizing feature map (SOFM), were developed with four hydraulic parameters, including the inlet depth, particle size, and the relative x and y particle positions. The five distinct statistical measures, consisting of the root mean square error (RMSE), Nash–Sutcliffe efficiency (NSE), mean absolute error (MAE), mean value accounted for (MVAF), and total variance explained (TVE), were used to assess the performance of the models. The SOFM with the 25 × 25 Kohonen map had shown superior results with RMSE of 0.001307, NSE of 0.7170, MAE of 0.000647, MVAF of 101.25%, and TVE of 71.71%.
Control Method for Flexible Joints in Manipulator Based on BP Neural Network Tuning PI Controller
Authors: Yang Hexu , Li Xiaopeng , Xu Jinchi , Shang Dongyang , Qu Xingchao
Published: December 2021

With the development of robot technology, integrated joints with small volume and convenient installation have been widely used. Based on the double inertia system, an integrated joint motor servo system model considering gear angle error and friction interference is established, and a joint control strategy based on BP neural network and pole assignment method is designed to suppress the vibration of the system. Firstly, the dynamic equation of a planetary gear system is derived based on the Lagrange method, and the gear vibration of angular displacement is calculated. Secondly, the vibration displacement of the sun gear is introduced into the motor servo system in the form of the gear angle error, and the double inertia system model including angle error and friction torque is established. Then, the PI controller parameters are determined by pole assignment method, and the PI parameters are adjusted in real time based on the BP neural network, which effectively suppresses the vibration of the system. Finally, the effects of friction torque, pole damping coefficient and control strategy on the system response and the effectiveness of vibration suppression are analyzed.
On g-Noncommuting Graph of a Finite Group Relative to Its Subgroups
Authors: Sharma Monalisha , Nath Rajat Kanti , Shang Yilun
Published: December 2021

Let H be a subgroup of a finite non-abelian group G and g∈G. Let Z(H,G)={x∈H:xy=yx,∀y∈G}. We introduce the graph ΔH,Gg whose vertex set is G\Z(H,G) and two distinct vertices x and y are adjacent if x∈H or y∈H and [x,y]≠g,g−1, where [x,y]=x−1y−1xy. In this paper, we determine whether ΔH,Gg is a tree among other results. We also discuss about its diameter and connectivity with special attention to the dihedral groups.
E-Learning Development Based on Internet of Things and Blockchain Technology during COVID-19 Pandemic
Authors: Rahmani Amir Masoud , Ali Naqvi Rizwan , Hussain Malik Mazhar , Malik Tauqeer Safdar , Sadrishojaei Mahyar , Hosseinzadeh Mehdi , Al-Musawi Ali
Published: December 2021

The suspension of institutions around the world in early 2020 due to the COVID-19 virus did not stop the learning process. E-learning concepts and digital technologies enable students to learn from a safe distance while continuing their educational pursuits. Currently, the Internet of Things (IoT) is one of the most rapidly increasing technologies in today’s digital world; and e-learning is one of the most powerful learning methods available. In today’s world, smart devices and new technologies assist teachers in concentrating on new models of student learning while avoiding time wastage. By examining the characteristics of the Internet of Things and the challenges that exist in the field of e-learning, the potential functions, benefits, and advancements of utilizing the Internet of Things in online education are identified and discussed. This article examines the existing and future condition of the Internet of Things world as it pertains to the topic of education and sophisticated capabilities available through the Internet of Things that enable the application of e-learning after an architecture has been designed. Students’ pulse rates, brain waves, and skin resistance are measured in real time by a collection of IoT sensors, including cameras, microphones, and wearable gadgets. By utilizing the proposed architecture, universities can change their distance learning tactics to maximize resources and boost efficiency without changing their overall academic activities. According to the study’s findings, e-learning has a favorable and statistically significant impact on students’ flexibility, learning experience, educational productivity, and overall quality of education.
Preoperative Chemoradiotherapy for Gastroesophageal Junction Adenocarcinoma Modified by PET/CT: Results of Virtual Planning Study
Authors: Slavik Marek , Burkon Petr , Selingerova Iveta , Krupa Pavel , Kazda Tomas , Stankova Jaroslava , Nikl Tomas , Hejnova Renata , Rehak Zdenek , Osmera Pavel , Prochazka Tomas , Dvorakova Eva , Pospisil Petr , Grell Peter , Slampa Pavel , Obermannova Radka
Published: December 2021

Background and Objectives: The treatment of gastroesophageal junction (GEJ) adenocarcinoma consists of either perioperative chemotherapy or preoperative chemoradiotherapy. Radiotherapy (RT) in the neoadjuvant setting is associated with a higher probability of resections with negative margins (R0) and better tumor regression rate, which might be enhanced by incrementing RT dose with potential impact on treatment results. This virtual planning study demonstrates the feasibility of increasing the dose to GEJ tumor and involved nodes using PET/CT imaging. Materials and Methods: 16 patients from the chemoradiotherapy arm of the phase II GastroPET study were treated by a prescribed dose of 45.0 Gray (Gy) in 25 fractions. PET/CT was performed before treatment. The prescribed dose was virtually boosted on PET/CT-positive areas to 54.0 Gy by 9 Gy in 5 fractions. Dose-volume histograms (DVH) were compared, and normal tissue complication (NTCP) modeling was performed for both dose schedules. Results: DVHs were exceeded in mean heart dose in one case for 45.0 Gy and two cases for 54.0 Gy, peritoneal space volume criterion V45Gy < 195 ccm in three cases for 54.0 Gy and V15Gy < 825 ccm in one case for both dose schedules. The left lung volume of 25 Gy isodose exceeded 10% in most cases for both schedules. The NTCP values for the heart, spine, liver, kidneys and intestines were zero for both schemes. An increase in NTCP value was for lungs (median 3.15% vs. 4.05% for 25 × 1.8 Gy and 25 + 5 × 1.8 Gy, respectively, p = 0.013) and peritoneal space (median values for 25 × 1.8 Gy and 25 + 5 × 1.8 Gy were 3.3% and 14.25%, respectively, p < 0.001). Conclusion: Boosting PET/CT-positive areas in RT of GEJ tumors is feasible, but prospective trials are needed.
Pain Experienced during Various Dental Procedures: Clinical Trial Comparing the Use of Traditional Syringes with the Controlled-Flow Delivery Dentapen® Technique
Authors: Fernández-Castellano Erick Rafael , Blanco-Antona Leticia Alejandra , Vicente-Galindo Purificación , Amor-Esteban Víctor , Flores-Fraile Javier
Published: December 2021

Background and Objectives: Currently, one of the most discouraging aspects for many patients undergoing dental procedures is the administration of anaesthesia. Consequently, there is a constant search for new techniques to avoid the invasive and painful nature of the injection. A new motorised syringe system (Dentapen®) has recently been developed, standing out for its convenience and ease of use. Material and Methods: Randomised, controlled, single-blind, and single-centre study including 178 voluntary adult participants aged between 18 and 90 years. Individuals were randomly assigned using a randomised table. Patients were asked to rate the level of pain experienced during the injections, using a 10-point visual analogue scale (VAS). The following data were recorded: pain index, heart rate, blood pressure, and saturation, both before and after anaesthesia. Results: Of the total 178 participants, 87 participants (48.9%) were men and 91 (51.1%) were women. The first variable to be assessed was the pain experienced by patients when anaesthetised with a syringe, obtaining a mean value of 2.63 ± 1.86 on the VAS with the conventional syringe and 1.06 ± 1.28 with the Dentapen® syringe, showing statistically significant differences (p-value < 0.01). When stratifying, based on the procedure that was undertaken, differences were also significant for all treatments (p-value < 0.01) except for endodontics, where differences were likely to be significant (p-value = 0.02). Conclusions: In conclusion, from a clinical standpoint, the Dentapen® syringe is a valid alternative to traditional infiltration syringes, causing minimum pain with the injection.
Emerging Therapeutic Concepts and Latest Diagnostic Advancements Regarding Neuroendocrine Tumors of the Gynecologic Tract
Authors: Georgescu Tiberiu-Augustin , Bohiltea Roxana Elena , Munteanu Octavian , Furtunescu Florentina , Lisievici Antonia-Carmen , Grigoriu Corina , Gherghiceanu Florentina , Vlădăreanu Emilia Maria , Berceanu Costin , Ducu Ionita , Iordache Ana-Maria
Published: December 2021

Neuroendocrine neoplasms (NENs) are particularly rare in all sites of the gynecological tract and include a variety of neoplasms with variable prognosis, dependent on histologic subtype and site of origin. Following the expert consensus proposal of the International Agency for Research on Cancer (IARC), the approach in the latest World Health Organization (WHO) Classification System of the Female Genital Tumours is to use the same terminology for NENs at all body sites. The main concept of this novel classification framework is to align it to all other body sites and make a clear distinction between well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). The previous WHO Classification System of the Female Genital Tumours featured more or less the same principle, but used the terms ‘low-grade neuroendocrine tumor’ and ‘high-grade neuroendocrine carcinoma’. Regardless of the terminology used, each of these two main categories include two distinct morphological subtypes: NETs are represented by typical and atypical carcinoid and NEC are represented by small cell neuroendocrine carcinoma (SCNEC) and large cell neuroendocrine carcinoma (LCNEC). High-grade NECs, especially small cell neuroendocrine carcinoma tends to be more frequent in the uterine cervix, followed by the endometrium, while low-grade NETs usually occur in the ovary. NENs of the vulva, vagina and fallopian tube are exceptionally rare, with scattered case reports in the scientific literature.
Probiotics as Therapeutic Tools against Pathogenic Biofilms: Have We Found the Perfect Weapon?
Authors: Meroni Gabriele , Panelli Simona , Zuccotti Gianvincenzo , Bandi Claudio , Drago Lorenzo , Pistone Dario
Published: December 2021

Bacterial populations inhabiting a variety of natural and human-associated niches have the ability to grow in the form of biofilms. A large part of pathological chronic conditions, and essentially all the bacterial infections associated with implanted medical devices or prosthetics, are caused by microorganisms embedded in a matrix made of polysaccharides, proteins, and nucleic acids. Biofilm infections are generally characterized by a slow onset, mild symptoms, tendency to chronicity, and refractory response to antibiotic therapy. Even though the molecular mechanisms responsible for resistance to antimicrobial agents and host defenses have been deeply clarified, effective means to fight biofilms are still required. Lactic acid bacteria (LAB), used as probiotics, are emerging as powerful weapons to prevent adhesion, biofilm formation, and control overgrowth of pathogens. Hence, using probiotics or their metabolites to quench and interrupt bacterial communication and aggregation, and to interfere with biofilm formation and stability, might represent a new frontier in clinical microbiology and a valid alternative to antibiotic therapies. This review summarizes the current knowledge on the experimental and therapeutic applications of LAB to interfere with biofilm formation or disrupt the stability of pathogenic biofilms.
High Vaccenic Acid Content in Beef Fat Attenuates High Fat and High Carbohydrate Western Diet Induced Changes in Lipid Metabolism and Gut Microbiota in Pigs
Authors: Singh Vijay P. , Fontaine Melanie A. , Mangat Rabban , Fouhse Janelle M. , Diane Abdoulaye , Willing Benjamin P. , Proctor Spencer D.
Published: December 2021

High-fat diets (HFD) have been shown to induce substantial shifts in intestinal microbial community composition and activity which are associated with adverse metabolic outcomes. Furthermore, changes in microbial composition are affected by fatty acid composition; saturated, monounsaturated (MUFA), and industrial trans fats (iTFA) adversely affect microbial diversity while polyunsaturated fats (PUFA) have been shown to have neutral effects. The effects of naturally occurring trans fats on gut microbial composition are unknown. Vaccenic acid (VA) is the most abundant naturally occurring trans fat (abundant in meat and dairy), can be elevated by altering a cow’s diet, and has been shown to have hypolipidemic effects. The aim of this study was to determine how variations of VA content in beef fat affect gut microbial composition, insulin resistance, and lipid metabolism in pigs. Low birth weight (LBW) and control pigs were fed a control or high-fat, high-carbohydrate (HFHC) diet supplemented with beef fat containing either high or low VA levels for 7 weeks. An adapted modified oral glucose tolerance test and fat challenge test were performed at 9 weeks of age following implantation of jugular catheters. Impacts on microbial composition were assessed using 16S rRNA gene amplicon sequencing. The HFHC diet containing beef fat rich in VA had a mild insulin sensitizing effect (p < 0.05, slope of curve), increased plasma HDL cholesterol (p < 0.05, +28%), reduced postprandial plasma TG (p < 0.05), and showed protection from HFHC-induced changes to gut microbial composition in LBW pigs as compared to HFHC diet containing standard beef fat. This is the first study to show effects of natural trans fats on gut dysbiosis; further studies are needed to elucidate mechanisms.
Microorganisms as Shapers of Human Civilization, from Pandemics to Even Our Genomes: Villains or Friends? A Historical Approach
Authors: Rodríguez-Frías Francisco , Quer Josep , Tabernero David , Cortese Maria Francesca , Garcia-Garcia Selene , Rando-Segura Ariadna , Pumarola Tomas
Published: December 2021

Universal history is characterized by continuous evolution, in which civilizations are born and die. This evolution is associated with multiple factors, among which the role of microorganisms is often overlooked. Viruses and bacteria have written or decisively contributed to terrible episodes of history, such as the Black Death in 14th century Europe, the annihilation of pre-Columbian American civilizations, and pandemics such as the 1918 Spanish flu or the current COVID-19 pandemic caused by the coronavirus SARS-CoV-2. Nevertheless, it is clear that we could not live in a world without these tiny beings. Endogenous retroviruses have been key to our evolution and for the regulation of gene expression, and the gut microbiota helps us digest compounds that we could not otherwise process. In addition, we have used microorganisms to preserve or prepare food for millennia and more recently to obtain drugs such as antibiotics or to develop recombinant DNA technologies. Due to the enormous importance of microorganisms for our survival, they have significantly influenced the population genetics of different human groups. This paper will review the role of microorganisms as “villains” who have been responsible for tremendous mortality throughout history but also as “friends” who help us survive and evolve.
Characterization of a Secretory YML079-like Cupin Protein That Contributes to Sclerotinia sclerotiorum Pathogenicity
Authors: Fan Hongxia , Yang Wenwen , Nie Jiayue , Lin Chen , Wu Jian , Wu Dewei , Wang Youping
Published: December 2021

Sclerotinia sclerotiorum causes devastating diseases in many agriculturally important crops, including oilseed rape and sunflower. However, the mechanisms of Sclerotinia sclerotiorum pathogenesis remain poorly understood. In this study, we characterized a YML079-like cupin protein (SsYCP1) from Sclerotinia sclerotiorum. We showed that SsYCP1 is strongly expressed and secreted during Sclerotinia sclerotiorum infection. Sclerotinia sclerotiorum infection was promoted by SsYCP1 overexpression and inhibited by silencing this gene with synthetic double-stranded RNA. These results collectively indicate SsYCP1 as a putative effector protein that contributes to Sclerotinia sclerotiorum pathogenicity. These findings extend our understanding of effector-mediated Sclerotinia sclerotiorum pathogenesis and suggest a novel role for YML079-like cupin proteins in plant–pathogen interactions.
Host Factors Affect the Gut Microbiome More Significantly than Diet Shift
Authors: Lkhagva Enkhchimeg , Chung Hea-Jong , Ahn Ji-Seon , Hong Seong-Tshool
Published: December 2021

The determining factors of the composition of the gut microbiome are one of the main interests in current science. In this work, we compared the effect of diet shift (DS) from heavily relying on meatatarian diets to vegetarian diets and physical exercise (EX) on the composition of the gut microbiome after 3 months. Although both DS and EX affected the composition of the gut microbiome, the patterns of alteration were different. The α-diversity analyzed by InvSimpson, Shannon, Simpson, and Evenness showed that both EX and DS affected the microbiome, causing it to become more diverse, but EX affected the gut microbiome more significantly than DS. The β-diversity analyses indicated that EX and DS modified the gut microbiome in two different directions. Co-occurrence network analysis confirmed that both EX and DS modified the gut microbiome in different directions, although EX modified the gut microbiome more significantly. Most notably, the abundance of Dialister succinatiphilus was upregulated by EX, and the abundances of Bacteroides fragilis, Phascolarctobacterium faecium, and Megasphaera elsdenii were downregulated by both EX and DS. Overall, EX modulated the composition of the gut microbiome more significantly than DS, meaning that host factors are more important in determining the gut microbiome than diets. This work also provides a new theoretical basis for why physical exercise is more health-beneficial than vegetarian diets.
Detection of Systemic Canine Kobuvirus Infection in Peripheral Tissues and the Central Nervous System of a Fox Infected with Canine Distemper Virus
Authors: Kaiser Franziska K. , van Dyck Lydia , Jo Wendy K. , Schreiner Tom , Pfankuche Vanessa M. , Wohlsein Peter , Baumann Ilka , Peters Martin , Baumgärtner Wolfgang , Osterhaus Albert D. M. E. , Ludlow Martin
Published: December 2021

Canine kobuvirus (CaKV) is a globally distributed pathogen of dogs and is predominantly associated with infection of the gastrointestinal tract. However, an etiological link to enteric disease has not been established since CaKV has been identified in both asymptomatic dogs and animals with diarrheic symptoms. In this study, an extraintestinal CaKV infection was detected by next-generation sequencing in a fox (Vulpes vulpes) in Germany concomitant with a canine distemper virus (canine morbillivirus; CDV) co-infection. Phylogenetic analysis of the complete coding region sequence showed that this strain was most closely related to a CaKV strain detected in a dog in the United Kingdom in 2008. The tissue and cellular tropism of CaKV was characterized by the detection of viral antigens and RNA. CaKV RNA was detected by in situ hybridization in different tissues, including epithelial cells of the stomach and ependymal cells in the brain. The use of a new RT-qPCR assay for CaKV confirmed the systemic distribution of CaKV with viral RNA also detected in the lymph nodes, bladder, trachea, and brain. The detection of a CDV infection in this fox suggests that immunosuppression should be further investigated as a contributing factor to the enhanced extraintestinal spread of CaKV.
Insights into the Anaerobic Hydrolysis Process for Extracting Embedded EPS and Metals from Activated Sludge
Authors: Tonanzi Barbara , Gallipoli Agata , Gianico Andrea , Annesini Maria Cristina , Braguglia Camilla Maria
Published: December 2021

The amount of sewage sludge generated from wastewater treatment plants globally is unavoidably increasing. In recent years, significant attention has been paid to the biorefinery concept based on the conversion of waste streams to high-value products, material, and energy by microorganisms. However, one of the most significant challenges in the field is the possibility of controlling the microorganisms’ pathways in the anaerobic environment. This study investigated two different anaerobic fermentation tests carried out with real waste activated sludge at high organic loading rate (10 g COD L−1d−1) and short hydraulic retention time (HRT) to comprehensively understand whether this configuration enhances extracellular polymeric substance (EPS) and metal solubilisation. The quantity of EPS recovered increased over time, while the chemical oxygen demand to EPS ratio remained in the range 1.31–1.45. Slightly acidic conditions and sludge floc disintegration promoted EPS matrix disruption and release, combined with the solubilisation of organically bound toxic metals, such as As, Be, Cu, Ni, V, and Zn, thereby increasing the overall metal removal efficiency due to the action of hydrolytic microorganisms. Bacteroidetes, Firmicutes, and Chloroflexi were the most abundant phyla observed, indicating that the short HRT imposed on the systems favoured the hydrolytic and acidogenic activity of these taxa.
In Tuber Biocontrol of Potato Late Blight by a Collection of Phenazine-1-Carboxylic Acid-Producing Pseudomonas spp.
Authors: Léger Geneviève , Novinscak Amy , Biessy Adrien , Lamarre Simon , Filion Martin
Published: December 2021

Phenazine-1-carboxylic acid (PCA) produced by plant-beneficial Pseudomonas spp. is an antibiotic with antagonistic activities against Phytophthora infestans, the causal agent of potato late blight. In this study, a collection of 23 different PCA-producing Pseudomonas spp. was confronted with P. infestans in potato tuber bioassays to further understand the interaction existing between biocontrol activity and PCA production. Overall, the 23 strains exhibited different levels of biocontrol activity. In general, P. orientalis and P. yamanorum strains showed strong disease reduction, while P. synxantha strains could not effectively inhibit the pathogen’s growth. No correlation was found between the quantities of PCA produced and biocontrol activity, suggesting that PCA cannot alone explain P. infestans’ growth inhibition by phenazine-producing pseudomonads. Other genetic determinants potentially involved in the biocontrol of P. infestans were identified through genome mining in strains displaying strong biocontrol activity, including siderophores, cyclic lipopeptides and non-ribosomal peptide synthase and polyketide synthase hybrid clusters. This study represents a step forward towards better understanding the biocontrol mechanisms of phenazine-producing Pseudomonas spp. against potato late blight.
Mycobacterium abscessus Genetic Determinants Associated with the Intrinsic Resistance to Antibiotics
Authors: Gorzynski Mylene , Week Tiana , Jaramillo Tiana , Dzalamidze Elizaveta , Danelishvili Lia
Published: December 2021

Mycobacterium abscessus subsp. abscessus (MAB) is a fast-growing nontuberculous mycobacterium causing pulmonary infections in immunocompromised and immunocompetent individuals. The treatment of MAB infections in clinics is extremely challenging, as this organism is naturally resistant to most available antibiotics. There is limited knowledge on the mechanisms of MAB intrinsic resistance and on the genes that are involved in the tolerance to antimicrobials. To identify the MAB genetic factors, including the components of the cell surface transport systems related to the efflux pumps, major known elements contributing to antibiotic resistance, we screened the MAB transposon library of 2000 gene knockout mutants. The library was exposed at either minimal inhibitory (MIC) or bactericidal concentrations (BC) of amikacin, clarithromycin, or cefoxitin, and MAB susceptibility was determined through the optical density. The 98 susceptible and 36 resistant mutants that exhibited sensitivity below the MIC and resistance to BC, respectively, to all three drugs were sequenced, and 16 mutants were found to belong to surface transport systems, such as the efflux pumps, porins, and carrier membrane enzymes associated with different types of molecule transport. To establish the relevance of the identified transport systems to antibiotic tolerance, the gene expression levels of the export related genes were evaluated in nine MAB clinical isolates in the presence or absence of antibiotics. The selected mutants were also evaluated for their ability to form biofilms and for their intracellular survival in human macrophages. In this study, we identified numerous MAB genes that play an important role in the intrinsic mechanisms to antimicrobials and further demonstrated that, by targeting components of the drug efflux system, we can significantly increase the efficacy of the current antibiotics.
High Potential for Anaerobic Microbial Sulfur Oxidation in Oil Sands Tailings Ponds
Authors: Stasik Sebastian , Schmidt Juliane , Wendt-Potthoff Katrin
Published: December 2021

The biogenic production of toxic H2S gas in sulfate-rich oil sands tailings ponds is associated with strong environmental concerns. Beside precipitation into sulfide minerals and chemical re-oxidation, microbial sulfur oxidation may catalyze sulfide re-cycling but potentially contributes to acid rock drainage (ARD) generation. To evaluate the microbial potential for sulfur oxidation, we conducted a microcosm-based pilot study with tailings of an active pond. Incubations were performed under oxic and anoxic conditions, with and without KNO3 as an electron acceptor and thiosulfate as a common substrate for microbial sulfur oxidation. The highest potentials of sulfur oxidation occurred in oxic assays (1.21 mmol L−1 day−1). Under anoxic conditions, rates were significantly lower and dominated by chemical transformation (0.09 mmol L−1 day−1; p < 0.0001). The addition of KNO3 to anoxic incubations increased microbial thiosulfate oxidation 2.5-fold (0.23 mmol L−1 day−1; p = 0.0474), with complete transformation to SO42− coupled to NO3− consumption, pointing to the activity of sulfur-oxidizing bacteria (SOB) under nitrate-reducing conditions. Importantly, in the presence of KNO3, a decrease in sedimentary sulfides was associated with an increase in S0, which indicates the potential for microbially mediated oxidation of sulfide minerals and ARD generation. Furthermore, the comparative analysis of sediments from other anthropogenic aquatic habitats demonstrated high similarities with respect to viable SOB counts and corresponding activity rates.
Molecular Variability and Host Distribution of ‘Candidatus Phytoplasma solani’ Strains from Different Geographic Origins
Authors: Contaldo Nicoletta , Stepanović Jelena , Pacini Francesco , Bertaccini Assunta , Duduk Bojan
Published: December 2021

The knowledge of phytoplasma genetic variability is a tool to study their epidemiology and to implement an effective monitoring and management of their associated diseases. ‘Candidatus Phytoplasma solani’ is associated with “bois noir” disease in grapevines, and yellowing and decline symptoms in many plant species, causing serious damages during the epidemic outbreaks. The epidemiology of the diseases associated with this phytoplasma is complex and related to numerous factors, such as interactions of the host plant and insect vectors and spreading through infected plant propagation material. The genetic variability of ‘Ca. P. solani’ strains in different host species and in different geographic areas during the last two decades was studied by RFLP analyses coupled with sequencing on vmp1, stamp, and tuf genes. A total of 119 strains were examined, 25 molecular variants were identified, and the variability of the studied genes was linked to both geographic distribution and year of infection. The crucial question in ‘Ca. P. solani’ epidemiology is to trace back the epidemic cycle of the infections. This study presents some relevant features about differential strain distribution useful for disease monitoring and forecasting, illustrating and comparing the phytoplasma molecular variants identified in various regions, host species, and time periods.
Toxoplasmosis: Current and Emerging Parasite Druggable Targets
Authors: Hajj Rana El , Tawk Lina , Itani Shaymaa , Hamie Maguy , Ezzeddine Jana , El Sabban Marwan , El Hajj Hiba
Published: December 2021

Toxoplasmosis is a prevalent disease affecting a wide range of hosts including approximately one-third of the human population. It is caused by the sporozoan parasite Toxoplasma gondii (T. gondii), which instigates a range of symptoms, manifesting as acute and chronic forms and varying from ocular to deleterious congenital or neuro-toxoplasmosis. Toxoplasmosis may cause serious health problems in fetuses, newborns, and immunocompromised patients. Recently, associations between toxoplasmosis and various neuropathies and different types of cancer were documented. In the veterinary sector, toxoplasmosis results in recurring abortions, leading to significant economic losses. Treatment of toxoplasmosis remains intricate and encompasses general antiparasitic and antibacterial drugs. The efficacy of these drugs is hindered by intolerance, side effects, and emergence of parasite resistance. Furthermore, all currently used drugs in the clinic target acute toxoplasmosis, with no or little effect on the chronic form. In this review, we will provide a comprehensive overview on the currently used and emergent drugs and their respective parasitic targets to combat toxoplasmosis. We will also abridge the repurposing of certain drugs, their targets, and highlight future druggable targets to enhance the therapeutic efficacy against toxoplasmosis, hence lessening its burden and potentially alleviating the complications of its associated diseases.
Influence of the Substituents on the Opening of Silylepoxy Alcohols: 5-exo-Cyclization towards Tetrahydrofurans vs. Unexpected Side Reaction Leading to Tetrahydropyrans
Authors: Díez-Poza Carlos , Barbero Asunción
Published: December 2021

The regioselective ring opening of epoxy alcohols is an effective method for the synthesis of different types of oxacycles. The 5-exo opening being preferred vs. the 6-endo mode, according to Baldwin rules, the use of silyl-substituted oxiranes has been reported as a possible method to favor the 6-endo cyclization. However, there is a need for a detailed study on the different factors (structural factors, catalyst nature or conditions) that influence this process. In this paper, the acid-catalyzed cyclization of epoxysilyl alcohols was studied, focusing on the effect of substituents and reaction conditions on the outcome of the process. Two types of heterocycles (tetrahydrofurans or tetrahydropyrans) were selectively obtained depending on the structure of the initial epoxysilyl alcohol. Interestingly, cyclization of hindered epoxysilyl alcohols mainly proceeds through an unexpected side reaction, which implies a previous isomerization to an aldehyde. A mechanistic proposal for the formation of the different products is presented.
Development of a Continuous System for 2-Phenylethanol Bioproduction by Yeast on Whey Permeate-Based Medium
Authors: Drężek Karolina , Kozłowska Joanna , Detman Anna , Mierzejewska Jolanta
Published: December 2021

2-Phenylethanol (2-PE) is an alcohol with a rosy scent and antimicrobial activity, and therefore, it is widely used in the food and cosmetic industries as an aroma and preservative. This work was aimed to draw up a technology for 2-PE bioproduction on whey permeate, which is waste produced by the dairy industry, rich in lactase and proteins. Its composition makes it a harmful waste to dispose of; however, with a properly selected microorganism, it could be converted to a value-added product. Herein, two yeast Kluyveromyces marxianus strains and one Kluyveromyces lactis, isolated from dairy products, were tested for 2-PE production, firstly on standard media and then on whey permeate based media in batch cultures. Thereafter, the 2-PE bioproduction in a continuous system in a 4.8 L bioreactor was developed, and subsequently, the final product was recovered from culture broth. The results showed that the yield of 2-PE production increased by 60% in the continuous culture compared to batch culture. Together with a notable reduction of chemical oxygen demand for whey permeate, the present study reports a complete, effective, and environmentally friendly strategy for 2-PE bioproduction with a space-time yield of 57.5 mg L−1 h−1.
Magnolol and Honokiol Inhibited the Function and Expression of BCRP with Mechanism Exploration
Authors: Yu Chung-Ping , Li Pei-Ying , Chen Szu-Yu , Lin Shiuan-Pey , Hou Yu-Chi
Published: December 2021

Breast cancer resistance protein (BCRP), one of the ATP-binding cassette (ABC) transporters, was associated with the multidrug resistance (MDR) of chemotherapy. Magnolol (MN) and honokiol (HK) are major bioactive polyphenols of Magnolia officinalis. This study investigated the effects of MN and HK on the function and expression of BCRP for the purpose of developing BCRP inhibitor to overcome MDR. Cell lines including MDCKII-BCRP and MDCKII-WT were used for evaluating the function and expression of BCRP. The results showed that MN (100–12.5 µM) and HK (100–12.5 µM) significantly decreased the function of BCRP by 80~12% and 67~14%, respectively. In addition, MN and HK were verified as substrates of BCRP. Furthermore, MN and HK reduced the protein expression of BCRP, and inhibited the phosphorylation of epidermal growth factor receptor (EGFR) and phosphatidylinositol 3-kinase (PI3K). In conclusion, both MN and HK decreased the function and expression of BCRP via EGFR/PI3K signaling pathway. Therefore, both compounds were promising candidates for reversing the MDR of chemotherapy.
A Zn(II)-Based Sql Type 2D Coordination Polymer as a Highly Sensitive and Selective Turn-On Fluorescent Probe for Al3+
Authors: Pavlov Dmitry I. , Ryadun Alexey A. , Potapov Andrei S.
Published: December 2021

A luminescent coordination polymer with the overall formula {[Zn(tr2btd)(bpdc)]∙DMF}n (where tr2btd = 4,7-di(1H-1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole; bpdc = 4,4′-biphenyldicarboxylate) was synthesized and characterized by single-crystal and powder X-ray diffraction, thermogravimetric, infrared spectroscopy, and elemental analyses. Luminescent properties of the obtained compound were studied in detail both in the solid state and as a suspension in N,N-dimethylacetamide (DMA). It was found that {[Zn(tr2btd)(bpdc)]∙DMF}n exhibits bright turquoise luminescence with excellent quantum efficiency and demonstrates turn-on fluorescence enhancement effect upon soaking in DMA Al3+ solution. Fluorescence titration experiments were carried out and the detection limit for Al3+ ions was calculated to be 120 nM, which is among the lowest reported values for similar materials. Moreover, compound demonstrated excellent selectivity and reusability, and the mechanism of the response is discussed. These results indicate that {[Zn(tr2btd)(bpdc)]∙DMF}n is a promising probe for sensitive fluorescent Al3+ detection.
Luteolin-3′-O-Phosphate Inhibits Lipopolysaccharide-Induced Inflammatory Responses by Regulating NF-κB/MAPK Cascade Signaling in RAW 264.7 Cells
Authors: Kim Jung-Hwan , Park Tae-Jin , Park Jin-Soo , Kim Min-Seon , Chi Won-Jae , Kim Seung-Young
Published: December 2021

Luteolin (LT), present in most plants, has potent anti-inflammatory properties both in vitro and in vivo. Furthermore, some of its derivatives, such as luteolin-7-O-glucoside, also exhibit anti-inflammatory activity. However, the molecular mechanisms underlying luteolin-3′-O-phosphate (LTP)-mediated immune regulation are not fully understood. In this paper, we compared the anti-inflammatory properties of LT and LTP and analyzed their molecular mechanisms of action; we obtained LTP via the biorenovation of LT. We investigated the anti-inflammatory activities of LT and LTP in macrophage RAW 264.7 cells. We confirmed from previously reported literature that LT inhibits the production of nitric oxide and prostaglandin E2, as well as the expression of inducible NO synthetase and cyclooxygenase-2. In addition, expressions of inflammatory genes and mediators, such as tumor necrosis factor-α, interleukin-6, and interleukin-1β, were suppressed. LTP showed anti-inflammatory activity similar to LT, but better anti-inflammatory activity in all the experiments, while also inhibiting mitogen-activated protein kinase and nuclear factor-kappa B more effectively than LT. At a concentration of 10 μM, LTP showed differences of 2.1 to 44.5% in the activity compared to LT; it also showed higher anti-inflammatory activity. Our findings suggest that LTP has stronger anti-inflammatory activity than LT.
Simple Ion–Gas Mixtures as a Source of Key Molecules Relevant to Prebiotic Chemistry
Authors: Paula Samuel , Goulding Liam S. , Robertson Katherine N. , Clyburne Jason A. C.
Published: December 2021

Very simple chemistry can result in the rapid and high-yield production of key prebiotic inorganic molecules. The two reactions investigated here involve such simple systems, (a) carbon disulfide (CS2) and acetate (CH3COO¯) and (b) sulfur dioxide (SO2) and formate (HCOO¯). They have been carried out under non-aqueous conditions, either in an organic solvent or with a powdered salt exposed to the requisite gas. Under such dry conditions the first reaction generated the thioacetate anion [CH3COS]¯ while the second produced the radical [SO2·]¯anion. Anhydrous conditions are not rare and may have arisen on the early earth at sites where an interface between different phases (liquid/gas or solid/gas) could be generated. This is one way to rationalize the formation of molecules and ions (such as we have produced) necessary in the prebiotic world. Interpretation of our results provides insight into scenarios consistent with the more prominent theories of abiogenesis.
Structural Characterization of Ectodomain G Protein of Respiratory Syncytial Virus and Its Interaction with Heparan Sulfate: Multi-Spectroscopic and In Silico Studies Elucidating Host-Pathogen Interactions
Authors: Hamza Abu , Samad Abdus , Imam Md. Ali , Faizan Md. Imam , Ahmed Anwar , Almajhdi Fahad N. , Hussain Tajamul , Islam Asimul , Parveen Shama
Published: December 2021

The global burden of disease caused by a respiratory syncytial virus (RSV) is becoming more widely recognized in young children and adults. Heparan sulfate helps in attaching the virion through G protein with the host cell membrane. In this study, we examined the structural changes of ectodomain G protein (edG) in a wide pH range. The absorbance results revealed that protein maintains its tertiary structure at physiological and highly acidic and alkaline pH. However, visible aggregation of protein was observed in mild acidic pH. The intrinsic fluorescence study shows no significant change in the λmax except at pH 12.0. The ANS fluorescence of edG at pH 2.0 and 3.0 forms an acid-induced molten globule-like state. The denaturation transition curve monitored by fluorescence spectroscopy revealed that urea and GdmCl induced denaturation native (N) ↔ denatured (D) state follows a two-state process. The fluorescence quenching, molecular docking, and 50 ns simulation measurements suggested that heparan sulfate showed excellent binding affinity to edG. Our binding study provides a preliminary insight into the interaction of edG to the host cell membrane via heparan sulfate. This binding can be inhibited using experimental approaches at the molecular level leading to the prevention of effective host–pathogen interaction.
Study by Optical Spectroscopy of Bismuth Emission in a Nanosecond-Pulsed Discharge Created in Liquid Nitrogen
Authors: Nominé Anna V. , Noel Cédric , Gries Thomas , Nominé Alexandre , Milichko Valentin A. , Belmonte Thierry
Published: December 2021

Time-resolved optical emission spectroscopy of nanosecond-pulsed discharges ignited in liquid nitrogen between two bismuth electrodes is used to determine the main discharge parameters (electron temperature, electron density and optical thickness). Nineteen lines belonging to the Bi I system and seven to the Bi II system could be recorded by directly plunging the optical fibre into the liquid in close vicinity to the discharge. The lack of data for the Stark parameters to evaluate the broadening of the Bi I lines was solved by taking advantage of the time-resolved information supported by each line to determine them. The electron density was found to decrease exponentially from 6.5 ± 1.5 × 1016 cm−3 200 ns after ignition to 1.0 ± 0.5 × 1016 cm−3 after 1050 ns. The electron temperature was found to be 0.35 eV, close to the value given by Saha’s equation.