bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Resin Infiltration on Enamel: A Systematic Review and Meta-Analysis
Authors: Soveral Madalena , Machado Vanessa , Botelho João , Mendes José João , Manso Cristina
Published: August 2021

Subsurface enamel demineralization beneath an intact surface layer or white spots lesions (WSL) can and should be treated with non-invasive procedures to impede the development of a cavitated lesion. We aim to analyze if infiltrative resin improves enamel roughness, microhardness, shear bond strength, and penetration depth. MEDLINE [via Pubmed], Cochrane Central Register of Controlled Trials, Embase, Web of Science, Scholar, and LILACS were searched until May 2021. Methodological quality was assessed using the Joanna Briggs Institute Clinical Appraisal Checklist for Experimental Studies. Pairwise ratio of means (ROM) meta-analyses were carried out to compare the enamel properties after treatment with infiltrative resin on sound enamel and WSLs. From a total of 1604 articles, 48 studies were included. Enamel surface roughness decreased 35% in sound enamel (95%CI: 0.49–0.85, I2 = 98.2%) and 54% in WSLs (95%CI: 0.29–0.74, I2 = 98.5%). Microhardness reduced 24% in sound enamel (95%CI: 0.73–0.80, I2 = 99.1%) and increased by 68% in WSLs (95%CI: 1.51; 1.86, I2 = 99.8%). Shear bond strength reduced of 25% in sound enamel (95%CI: 0.60; 0.95, I2 = 96.9%) and increased by 89% in WSLs (95%CI: 1.28–2.79, I2 = 99.8%). Penetration depth was 65.39% of the WSLs (95%CI: 56.11–74.66, I2 = 100%). Infiltrative resins effectively promote evident changes in enamel properties in sound and WSLs. Future studies with long-term follow-ups are necessary to corroborate these results from experimental studies.
Simulation-Based Operational Evaluation of a Single-Berth Multipurpose Seaport with Wharf Space Restriction
Authors: Xie Wei , Zhuge Siyi , Wu Yongzhong , Xiao Dan
Published: August 2021

Overcapacity of seaport infrastructure has been a common issue in many countries in recent years. Cautious investment decisions shall be made on the basis of realistic capacity evaluation and productivity improvement of existing ports. However, operational analysis and evaluation of a seaport is not always easy, especially for multipurpose terminals which are commonly seen in developing countries. These small-scaled multipurpose seaports handle different cargo types with multiple interrelated processes and varying handling methods and process times. This paper studies a single-berth multipurpose seaport with wharf space restriction in Indonesia and shows how the simulation model can be essential and significantly helpful in the evaluation of the port’s productivity and realistic capacity. Furthermore, a new handling method is proposed and evaluated by the simulation model. The simulation approach and related results help the port operator in making decisions regarding port improvement and future expansion investments.
Benzoic Acid and Its Hydroxylated Derivatives Suppress Early Blight of Tomato (Alternaria solani) via the Induction of Salicylic Acid Biosynthesis and Enzymatic and Nonenzymatic Antioxidant Defense Machinery
Authors: Nehela Yasser , Taha Naglaa A. , Elzaawely Abdelnaser A. , Xuan Tran Dang , A. Amin Mohammed , Ahmed Mohamed E. , El-Nagar Asmaa
Published: August 2021

Tomato early blight, caused by Alternaria solani, is a destructive foliar fungal disease. Herein, the potential defensive roles of benzoic acid (BA) and two of its hydroxylated derivatives, ρ-hydroxybenzoic acid (HBA), and protocatechuic acid (PCA) against A. solani were investigated. All tested compounds showed strong dose-dependent fungistatic activity against A. solani and significantly reduced the disease development. Benzoic acid, and its hydroxylated derivatives, enhanced vegetative growth and yield traits. Moreover, BA and its derivatives induce the activation of enzymatic (POX, PPO, CAT, SlAPXs, and SlSODs) and non-enzymatic (phenolics, flavonoids, and carotenoids) antioxidant defense machinery to maintain reactive oxygen species (ROS) homeostasis within infected leaves. Additionally, BA and its hydroxylated derivatives induce the accumulation of salicylic acid (SA) and its biosynthetic genes including isochorismate synthase (SlICS), aldehyde oxidases (SlAO1 and SlAO2), and phenylalanine ammonia-lyases (SlPAL1, SlPAL2, SlPAL3, SlPAL5, and SlPAL6). Higher SA levels were associated with upregulation of pathogenesis-related proteins (SlPR-1, SlPR1a2, SlPRB1-2, SlPR4, SlPR5, SlPR6), nonexpressor of pathogenesis-related protein 1 (SlNPR1), and salicylic acid-binding protein (SlSABP2). These findings outline the potential application of BA and its hydroxylated derivatives as a sustainable alternative control strategy for early blight disease and also deciphering the physiological and biochemical mechanisms behind their protective role.
Treating (Recurrent) Vulvovaginal Candidiasis with Medical-Grade Honey—Concepts and Practical Considerations
Authors: van Riel Senna J. J. M. , Lardenoije Celine M. J. G. , Oudhuis Guy J. , Cremers Niels A. J.
Published: August 2021

Recurrent vulvovaginal candidiasis (RVVC) is a relapsing vaginal fungal infection caused by Candida species. The prevalence varies among age populations and can be as high as 9%. Treatment options are limited, and in 57% of the cases, relapses occur within six months after fluconazole maintenance therapy, which is the current standard of care. The pathogenesis of RVVC is multifactorial, and recent studies have demonstrated that the vaginal microenvironment and activity of the immune system have a strong influence on the disease. Medical-grade honey (MGH) has protective, antimicrobial, and immunomodulatory activity and forms a putative alternative treatment. Clinical trials have demonstrated that honey can benefit the treatment of bacterial and Candida-mediated vaginal infections. We postulate that MGH will actively fight ongoing infections; eradicate biofilms; and modulate the vaginal microenvironment by its anti-inflammatory, antioxidative, and immunomodulatory properties, and subsequently may decrease the number of relapses when compared to fluconazole. The MGH formulation L-Mesitran Soft has stronger antimicrobial activity against various Candida species than its raw honey. In advance of a planned randomized controlled clinical trial, we present the setup of a study comparing L-Mesitran Soft with fluconazole and its practical considerations.
Hedging Long-Dated Oil Futures and Options Using Short-Dated Securities—Revisiting Metallgesellschaft
Authors: Doran James S. , Ronn Ehud I.
Published: August 2021

Since the collapse of the Metallgesellschaft AG due to hedging losses in 1993, energy practitioners have been concerned with the ability to hedge long-dated linear and non-linear oil liabilities with short-dated futures and options. This paper identifies a model-free non-parametric approach to extrapolating futures prices and implied volatilities. When we expand the analysis to implementing hedge portfolios for long-dated futures or option contracts over the time period 2007–2017, we utilize the useful benchmark of hedge ratios arising from Schwartz and Smith. With respect to the empirical consequences of hedging long-dated futures and options with their short-dated counterparts, we find that the long-term tracking errors are, on average, quite close to zero, but there is increasing risk entailed in attempting to do so, as the hedge-tracking errors for both futures and option contracts increase with time-to-maturity.
Substituting Organic Fertilizer for Chemical Fertilizer: Evidence from Apple Growers in China
Authors: Fang Pingping , Abler David , Lin Guanghua , Sher Ali , Quan Quan
Published: August 2021

This study investigates the key factors affecting farmers’ decisions to use chemical fertilizer and/or organic fertilizer in Chinese apple production. This study calculates partial output elasticities and elasticities of the substitution between organic and chemical fertilizer, using a stochastic frontier production function model and data for 2017–2019. Subsequently, it analyzes how different sales channels impact the partial output elasticities of organic fertilizer. It also examines the impact of economic incentives on organic fertilizer use and technical inefficiency levels in apple production. The empirical results indicate that the organic matter in organic fertilizer has a medium level of substitutability with nitrogen, phosphorus, and potassium in chemical fertilizer. Further, the results indicate that an increase in the total number of available sales channels incentivizes farms to use more organic fertilizer to optimize apple quantity at the expense of the quality. Contrary, the use of any of the three most commonly used sales channels among apple growers (dealer door-to-door purchases, enterprise sales for juice pressing, and apple brokers) has the opposite effect on the use of organic fertilizer. From these findings, the subsidized provision of organic fertilizer and educating apple farmers about the economic and ecological benefits of sustainable land management measures are suggested. Finally, the study suggests measures to improve farmers’ income, sustainable land management, and lowering the footprint of chemical fertilizers in apple production in China.
Understanding Farmers’ Intention towards the Management and Conservation of Wetlands
Authors: Valizadeh Naser , Esfandiyari Bayat Samira , Bijani Masoud , Hayati Dariush , Viira Ants-Hannes , Tanaskovik Vjekoslav , Kurban Alishir , Azadi Hossein
Published: August 2021

The aim of the present research was to analyze the farmers’ intention towards participation in the management and conservation of wetlands through the lens of the extended theory of planned behavior (TPB). To do this, a cross-sectional survey of Iranian farmers was carried out. To select the samples, a multi-stage random sampling process with a proportional assignment was employed. The research instrument was a researcher-made questionnaire whose validity and reliability were verified using various quantitative and qualitative indicators. The results of the extended TPB using structural equation modeling showed that four variables, namely moral norms of participation in management and conservation (MNPMC), attitude towards participation in management and conservation (APMC), subjective norms towards participation in management and conservation (SNPMC), and self-concept about participation in management and conservation (SCPMC) had positive and significant impacts on intention towards participation in management and conservation (IPMC). The results also revealed that that entering MNPMC and SCPMC into TPB could increase its explanatory power. Also, the fit indicators supported the extended TPB. From a practical point of view, the present study provides justifications and insights for the use of MNPMC, APMC, SNPMC, and SCPMC in policies and programs intended to encourage farmers and local communities to participate in wetlands management and conservation.
DNA Polyelectrolyte Multilayer Coatings Are Antifouling and Promote Mammalian Cell Adhesion
Authors: Ouni Omar Abdelaziz , Subbiahdoss Guruprakash , Scheberl Andrea , Reimhult Erik
Published: August 2021

The ability of bacteria to adhere to and form biofilms on implant surfaces is the primary cause of implant failure. Implant-associated infections are difficult to treat, as the biofilm mode of growth protects microorganisms from the host’s immune response and antibiotics. Therefore, modifications of implant surfaces that can prevent or delay bacterial adhesion and biofilm formation are highly desired. In addition, the attachment and spreading of bone cells are required for successful tissue integration in orthopedic and dental applications. We propose that polyanionic DNA with a negatively charged phosphate backbone could provide a dual function to repel bacterial adhesion and support host tissue cell attachment. To this end, we developed polyelectrolyte multilayer coatings using chitosan (CS) and DNA on biomaterial surfaces via a layer-by-layer technique. The assembly of these coatings was characterized. Further, we evaluated staphylococcal adhesion and biofilm growth on the coatings as well as cytotoxicity for osteoblast-like cells (SaOS-2 cells), and we correlated these to the layer structure. The CS-DNA multilayer coatings impaired the biofilm formation of Staphylococcus by ~90% on both PMMA and titanium surfaces. The presence of cationic CS as the top layer did not hinder the bacteria-repelling property of the DNA in the coating. The CS-DNA multilayer coatings demonstrated no cytotoxic effect on SaOS-2 cells. Thus, DNA polyelectrolyte multilayer coatings could reduce infection risk while promoting host tissue cell attachment on medical implants.
Friction Stir Welding of 2205 Duplex Stainless Steel: Feasibility of Butt Joint Groove Filling in Comparison to Gas Tungsten Arc Welding
Authors: Ahmed Mohamed M. Z. , Abdelazem Khaled A. , El-Sayed Seleman Mohamed M. , Alzahrani Bandar , Touileb Kamel , Jouini Nabil , El-Batanony Ismail G. , Abd El-Aziz Hussein M.
Published: August 2021

This work investigates the feasibility of using friction stir welding (FSW) process as a groove filling welding technique to weld duplex stainless steel (DSS) that is extensively used by petroleum service companies and marine industries. For the FSW experiments, three different groove geometries without root gap were designed and machined in a DSS plates 6.5 mm thick. FSW were carried out to produce butt-joints at a constant tool rotation rate of 300 rpm, traverse welding speed of 25 mm/min, and tilt angle of 3o using tungsten carbide (WC) tool. For comparison, the same DSS plates were welded using gas tungsten arc welding (GTAW). The produced joints were evaluated and characterized using radiographic inspection, optical microscopy, and hardness and tensile testing. Electron back scattering diffraction (EBSD) was used to examine the grain structure and phases before and after FSW. The initial results indicate that FSW were used successfully to weld DSS joints with different groove designs with defect-free joints produced using the 60° V-shape groove with a 2 mm root face without root gap. This friction stir welded (FSWed) joint was further investigated and compared with the GTAW joint. The FSWed joint microstructure mainly consists of α and γ with significant grain refining; the GTWA weld contains different austenitic-phase (γ) morphologies such as grain boundary austenite (GBA), intragranular austenite precipitates (IGA), and Widmanstätten austenite (WA) besides the ferrite phase (α) in the weld zone (WZ) due to the used high heat input and 2209 filler rod. The yield strength, ultimate tensile strength, and elongation of the FSWed joint are enhanced over the GTAW weldment by 21%, 41%, and 66% and over the BM by 65%, 33%, and 54%, respectively. EBSD investigation showed a significant grain refining after FSW with grain size average of 1.88 µm for austenite and 2.2 µm for ferrite.
Erratum: Čapek et al. On the Weldability of Thick P355NL1 Pressure Vessel Steel Plates Using Laser Welding. Materials 2021, 14, 131
Authors: Čapek Jiří , Trojan Karel , Kec Jan , Černý Ivo , Ganev Nikolaj , Němeček Stanislav
Published: August 2021

The authors would like to correct the sentence in the “Materials and Methods” section of their article [...]
Bacterial Exposure to Nickel: Influence on Adhesion and Biofilm Formation on Orthodontic Archwires and Sensitivity to Antimicrobial Agents
Authors: Pavlic Andrej , Begic Gabrijela , Tota Marin , Abram Maja , Spalj Stjepan , Gobin Ivana
Published: August 2021

The presence of nickel could modify bacterial behavior and susceptibility to antimicrobial agents. Adhesion and biofilm formation on orthodontic archwires can be a source of bacterial colonization and possible health hazards. Staphylococcus aureus was subjected to exposure and adaptation to various sub-inhibitory concentrations of nickel. Five strains of bacteria adapted to nickel in concentrations of 62.5–1000 μg/mL were tested for adhesion and biofilm formation on nickel-titanium archwires. Archwires were previously incubated in artificial saliva. Bacteria were incubated with orthodontic wire with stirring for 4 h (adhesion) and 24 h (biofilm formation). The number of adherent bacteria was determined after sonication and cultivation on the Muller-Hinton agar. Disk diffusion method was performed on all bacteria to assess the differences in antimicrobial susceptibility. Bacteria adapted to lower concentrations of nickel adhered better to nickel-titanium than strains adapted to higher concentrations of nickel (p < 0.05). Biofilm formation was highest in strains adapted to 250 and 500 μg/mL of nickel (p < 0.05). The highest biofilm biomass was measured for strains adapted to 250 μg/mL, followed by those adapted to 1000 μg/mL. Bacteria adapted to lower concentrations of nickel demonstrated lower inhibition zone diameters in the disk diffusion method (p < 0.05), indicating increased antimicrobial resistance. In conclusion, bacteria adapted to 250 μg/mL of nickel ions adhered better, demonstrated higher biofilm formation and often had higher antimicrobial resistance than other adapted and non-adapted strains.
Methodological Aspects of Obtaining and Characterizing Composites Based on Biogenic Diatomaceous Silica and Epoxy Resins
Authors: Dobrosielska Marta , Dobrucka Renata , Brząkalski Dariusz , Gloc Michał , Rębiś Janusz , Głowacka Julia , Kurzydłowski Krzysztof J. , Przekop Robert E.
Published: August 2021

Diatomaceous earth are sediments of unicellular algal skeletons with a well-defined hierarchical structure. Despite many tests conducted on systems using diatomaceous earth and epoxy resins, we can find many differences in the methods of acquisition and characteristics of the composite, which may considerably affect the results. In our study, we have conducted tests to verify the impact of the method of obtaining samples and the degassing of the composite on its mechanical properties and standard deviation. The samples were cast in glass moulds and silicone moulds and then subjected to testing for their mechanical and functional properties, imaging with the use of an optical microscope and a scanning electron microscope. The tests have shown that, for samples cast in glass moulds, there is no heterogeneity within the area of the tested sample, as in the case of samples cast in silicone moulds. Silicone moulds allow for quite effective self-degassing of the resin due to the large area-to-mass ratio, and the small remaining air vesicles have a limited effect on the mechanical properties of the samples. The filler used also played a significant role. For systems containing base and rinsed diatomite, it is clear that the degassing of mixtures increases the tensile strength. For treated diatomite, the elongation at break grew along with increasing filler concentration, while for base diatomite, the improvement was observed for flexural strength and impact strength. A non-modified epoxy resin shows a tensile strength at 19.91 MPa (silicone mould cast). At the same time, the degassed, glass mould-cast systems containing 12% of base and rinsed diatoms showed a tensile strength of 27.4 MPa and 44.7 MPa, respectively. We have also observed that the higher the filler concentration, the higher were the tensile strength values, which for the rinsed diatoms reached over 55.1 MPa and for the base diatoms were maximum of 43.8 MPa. The tests, therefore, constitute a set of guidelines and recommendations for testing with the use of fillers showing an extended inner structure.
Effects of Different Hard Finishing Processes on Gear Excitation
Authors: Trübswetter Maximilian , Götz Joshua , Kohn Bernhard , Otto Michael , Stahl Karsten
Published: August 2021

Gearboxes are essential in mechanical drive trains for power transmission. A low noise emission and thus an optimized excitation behavior is a substantial design objective for many applications in terms of comfort and operational safety. There exist numerous processes for manufacturing gears, which all show different properties in relation to the process variables and, therefore, differences in the resulting accuracy and quality of the gear flank. In this paper, the influence of three different manufacturing processes for hard finishing—continuous generating grinding, polish grinding and gear skiving—on the surface structure of gear flanks and the excitation behavior is investigated experimentally and analyzed by the application force level. A tactile scanning of the gear flanks determines the flank surface structure and the deviations from the desired geometry. A torsional acceleration measurement during speed ramp-ups at different load levels is used to analyze the excitation of the gears. The results show only a minor influence of the surface structure on the application force level. The excitation behavior is dominated by the influence of the flank modification and its deviation from the design values.
Infinite Sum of the Incomplete Gamma Function Expressed in Terms of the Hurwitz Zeta Function
Authors: Reynolds Robert , Stauffer Allan
Published: August 2021

We apply our simultaneous contour integral method to an infinite sum in Prudnikov et al. and use it to derive the infinite sum of the Incomplete gamma function in terms of the Hurwitz zeta function. We then evaluate this formula to derive new series in terms of special functions and fundamental constants. All the results in this work are new.
A Non-Parametric Analysis of the Relationship between Business Experience and Entrepreneurial Intention of Final-Year University Students
Authors: Hudea Oana Simona , Toma Sorin-George , Burcea Marin
Published: August 2021

Last decades have witnessed that exposure to business activities, through family and direct experience, positively influences students’ entrepreneurial intention (EI). The paper aims to present and analyze the relationship between business experience (BE) and EI in the case of final-year university students, specialized in business administration and marketing, resorting to this end to a standardized questionnaire, developed by the authors and finalized following a pilot survey. The hypotheses considered, centered on the study of the existence of any contingency or correlational relationship between the BE of students, and their EI, based on related coefficients applicable in such case, have been confirmed, in line with similar studies. Theoretically, this paper contributes to the enrichment of the literature on students’ EI in higher education institutions (HEIs). Practically, students’ EI can be stimulated and encouraged by a deeper involvement of HEIs in entrepreneurship education, thereby creating a challenging entrepreneurial academic environment through a plethora of measures, such as establishing university spin-offs and closer relationships with their specific external stakeholders (e.g., entrepreneurs, businessmen).
Machine Learning Approach for Targeting and Recommending a Product for Project Management
Authors: Malik Hasmat , Afthanorhan Asyraf , Amirah Noor Aina , Fatema Nuzhat
Published: August 2021

Conventionally, a market research and strategy for a product depends on the interviews and an explicit cluster/society to identify the customer’s needs. Customer-created information (CCI), such as call-center data, online reviews, and social media posts, provides an opportunity to recognize the customer’s needs more efficiently. Moreover, developed conventional approaches are not compatible with large CCI datasets because most of the CCI-contents are repetitive and uninformative. In this paper, a machine learning approach for identifying the customer needs from the CCI dataset is proposed and its performance is evaluated for targeting and recommending a new product for project management. After the identification of the needs of the customer, information can be used to develop a market strategy, new product launching, brand positioning and much more long/short term planning.
Geometric Numerical Integration of Liénard Systems via a Contact Hamiltonian Approach
Authors: Zadra Federico , Bravetti Alessandro , Seri Marcello
Published: August 2021

Starting from a contact Hamiltonian description of Liénard systems, we introduce a new family of explicit geometric integrators for these nonlinear dynamical systems. Focusing on the paradigmatic example of the van der Pol oscillator, we demonstrate that these integrators are particularly stable and preserve the qualitative features of the dynamics, even for relatively large values of the time step and in the stiff regime.
Constructing an Adoption Model of Proactive Environmental Strategy: A Novel Quantitative Method of the Multi-Level Growth Curve Model
Authors: Huang Stanley Y. B. , Lee Shih-Chin , Lee Yue-Shi
Published: August 2021

To fill in the literature flaws that have not been detected in previous studies, this research, therefore, examines the driving factors of proactive environmental strategy (PES). First, this research proposes how corporate social responsibility (CSR) predicts the agricultural company’s PES through the intermediary mechanism of green organization identification (GOI) of the top management team (TMT) according to symbolic context and theory of high-level echelon, to solve the first gap in exploring what factors can drive the PES. Second, this research proposes a multi-level growth curve model (MGCM) to solve how individuals adjust their behavioral intentions over time according to their translation and understanding of their use environment, because past studies consist of almost cross-sectional properties. Third, past research has also neglected the multi-level framework, leading to hierarchical reasoning bias. Therefore, this research believes that the MGCM can fill in the multi-level gap. Finally, this research collected 400 TMT employees from 100 different agricultural companies in Taiwan in three-stage time for six months. The results show that CSR will significantly lead to more growth in GOI, and more growth in GOI will lead to more growth in PES adoption. The research results can not only advance the agricultural sustainability literature but also serve as a guide for agricultural companies to implement PES.
Culturable Microorganisms Associated with Sea Cucumbers and Microbial Natural Products
Authors: Chen Lei , Wang Xiao-Yu , Liu Run-Ze , Wang Guang-Yu
Published: August 2021

Sea cucumbers are a class of marine invertebrates and a source of food and drug. Numerous microorganisms are associated with sea cucumbers. Seventy-eight genera of bacteria belonging to 47 families in four phyla, and 29 genera of fungi belonging to 24 families in the phylum Ascomycota have been cultured from sea cucumbers. Sea-cucumber-associated microorganisms produce diverse secondary metabolites with various biological activities, including cytotoxic, antimicrobial, enzyme-inhibiting, and antiangiogenic activities. In this review, we present the current list of the 145 natural products from microorganisms associated with sea cucumbers, which include primarily polyketides, as well as alkaloids and terpenoids. These results indicate the potential of the microorganisms associated with sea cucumbers as sources of bioactive natural products.
SARS-CoV-2 Spike Pseudoviruses: A Useful Tool to Study Virus Entry and Address Emerging Neutralization Escape Phenotypes
Authors: Kalkeri Raj , Cai Zhaohui , Lin Shuling , Farmer John , Kuzmichev Yury V. , Koide Fusataka
Published: August 2021

SARS-CoV-2 genetic variants are emerging around the globe. Unfortunately, several SARS-CoV-2 variants, especially variants of concern (VOCs), are less susceptible to neutralization by the convalescent and post-vaccination sera, raising concerns of increased disease transmissibility and severity. Recent data suggests that SARS-CoV-2 neutralizing antibody levels are a reliable correlate of vaccine-mediated protection. However, currently used BSL3-based virus micro-neutralization (MN) assays are more laborious, time-consuming, and expensive, underscoring the need for BSL2-based, cost-effective neutralization assays against SARS-CoV-2 variants. In light of this unmet need, we have developed a BSL-2 pseudovirus-based neutralization assay (PBNA) in cells expressing the human angiotensin-converting enzyme-2 (hACE2) receptor for SARS-CoV-2. The assay is reproducible (R2 = 0.96), demonstrates a good dynamic range and high sensitivity. Our data suggest that the biological Anti-SARS-CoV-2 research reagents such as NIBSC 20/130 show lower neutralization against B.1.351 SA (South Africa) and B.1.1.7 UK (United Kingdom) VOC, whereas a commercially available monoclonal antibody MM43 retains activity against both these variants. SARS-CoV-2 spike PBNAs for VOCs would be useful tools to measure the neutralization ability of candidate vaccines in both preclinical models and clinical trials and would further help develop effective prophylactic countermeasures against emerging neutralization escape phenotypes.
Role of Rhizospheric Microbiota as a Bioremediation Tool for the Protection of Soil-Plant Systems from Microcystins Phytotoxicity and Mitigating Toxin-Related Health Risk
Authors: Redouane El Mahdi , Mugani Richard , Lahrouni Majida , Martins José Carlos , Zerrifi Soukaina El Amrani , Oufdou Khalid , Campos Alexandre , Vasconcelos Vitor , Oudra Brahim
Published: August 2021

Frequent toxic cyanoblooms in eutrophic freshwaters produce various cyanotoxins such as the monocyclic heptapeptides microcystins (MCs), known as deleterious compounds to plant growth and human health. Recently, MCs are a recurrent worldwide sanitary problem in irrigation waters and farmland soils due to their transfer and accumulation in the edible tissues of vegetable produce. In such cases, studies about the persistence and removal of MCs in soil are scarce and not fully investigated. In this study, we carried out a greenhouse trial on two crop species: faba bean (Vicia faba var. Alfia 321) and common wheat (Triticum aestivum var. Achtar) that were grown in sterile (microorganism-free soil) and non-sterile (microorganism-rich soil) soils and subjected to MC-induced stress at 100 µg equivalent MC-LR L−1. The experimentation aimed to assess the prominent role of native rhizospheric microbiota in mitigating the phytotoxic impact of MCs on plant growth and reducing their accumulation in both soils and plant tissues. Moreover, we attempted to evaluate the health risk related to the consumption of MC-polluted plants for humans and cattle by determining the estimated daily intake (EDI) and health risk quotient (RQ) of MCs in these plants. Biodegradation was liable to be the main removal pathway of the toxin in the soil; and therefore, bulk soil (unplanted soil), as well as rhizospheric soil (planted soil), were used in this experiment to evaluate the accumulation of MCs in the presence and absence of microorganisms (sterile and non-sterile soils). The data obtained in this study showed that MCs had no significant effects on growth indicators of faba bean and common wheat plants in non-sterile soil as compared to the control group. In contrast, plants grown in sterile soil showed a significant decrease in growth parameters as compared to the control. These results suggest that MCs were highly bioavailable to the plants, resulting in severe growth impairments in the absence of native rhizospheric microbiota. Likewise, MCs were more accumulated in sterile soil and more bioconcentrated in root and shoot tissues of plants grown within when compared to non-sterile soil. Thereby, the EDI of MCs in plants grown in sterile soil was more beyond the tolerable daily intake recommended for both humans and cattle. The risk level was more pronounced in plants from the sterile soil than those from the non-sterile one. These findings suggest that microbial activity, eventually MC-biodegradation, is a crucial bioremediation tool to remove and prevent MCs from entering the agricultural food chain.
Congenital Human Cytomegalovirus Infection: A Narrative Review of Maternal Immune Response and Diagnosis in View of the Development of a Vaccine and Prevention of Primary and Non-Primary Infections in Pregnancy
Authors: Gerna Giuseppe , Fornara Chiara , Furione Milena , Lilleri Daniele
Published: August 2021

Congenital cytomegalovirus infection (cCMV) may affect about 1% of all newborns all over the world as a result of either a primary or recurrent human cytomegalovirus (HCMV) infection. While about 90% of infants affected by cCMV are asymptomatic at birth, the remaining 10% are symptomatic often with neurodevelopmental impairment and sensorineural hearing loss. In view of identifying the best approach to vaccine prevention of cCMV, this review will examine the most important steps made in the study of the immune response to, and diagnosis of, HCMV infection. The maternal immune response and immune correlates of protection are being partially identified with a partial contribution given by our laboratory. The diagnosis of primary infection is often difficult to achieve in the first three months of pregnancy, which is the time primarily involved in virus transmission to the fetus in association with the most severe symptoms and sequelae. Prevention of cCMV is anticipated by prevention of primary infection in early pregnancy by means of different measures, such as (i) behavioral-educational measures, (ii) immunoglobulin administration, (iii) antiviral treatment with valaciclovir. However, the most promising approach to cCMV prevention appears to be the development of a non-living vaccine, including at least three viral antigens: gB, pentamer complex gHgLpUL128L, and pp65, which have been shown to be able to stimulate both the humoral and the cellular arms of the maternal immune response. Primary HCMV infection may be managed in pregnancy by counseling of the couples involved by a team of specialists that includes virologists, obstetricians, infectivologists and neonatologists.
Nicastrin-Like, a Novel Transmembrane Protein from Trypanosoma cruzi Associated to the Flagellar Pocket
Authors: Lechuga Guilherme Curty , Napoleão-Pêgo Paloma , Gomes Larissa Rodrigues , da Matta Durans Andressa , Provance David William , De-Simone Salvatore Giovanni
Published: August 2021

Nicastrin (NICT) is a transmembrane protein physically associated with the polytypical aspartyl protease presenilin that plays a vital role in the correct localization and stabilization of presenilin to the membrane-bound γ-secretase complex. This complex is involved in the regulation of a wide range of cellular events, including cell signaling and the regulation of endocytosed membrane proteins for their trafficking and protein processing. Methods: In Trypanosoma cruzi, the causal agent of the Chagas disease, a NICT-like protein (Tc/NICT) was identified with a short C-terminus orthologous to the human protein, a large ectodomain (ECD) with numerous glycosylation sites and a single-core transmembrane domain containing a putative TM-domain (457GSVGA461) important for the γ-secretase complex activity. Results: Using the Spot-synthesis strategy with Chagasic patient sera, five extracellular epitopes were identified and synthetic forms were used to generate rabbit anti-Tc/NICT polyclonal serum that recognized a ~72-kDa molecule in immunoblots of T. cruzi epimastigote extracts. Confocal microscopy suggests that Tc/NICT is localized in the flagellar pocket, which is consistent with data from our previous studies with a T. cruzi presenilin-like protein. Phylogenetically, Tc/NICT was localized within a subgroup with the T. rangeli protein that is clearly detached from the other Trypanosomatidae, such as T. brucei. These results, together with a comparative analysis of the selected peptide sequence regions between the T. cruzi and mammalian proteins, suggest a divergence from the human NICT that might be relevant to Chagas disease pathology. As a whole, our data show that a NICT-like protein is expressed in the infective and replicative stages of T. cruzi and may be considered further evidence for a γ-secretase complex in trypanosomatids.
The Upcoming 6Li Isotope Requirements Might Be Supplied by a Microalgal Enrichment Process
Authors: Díaz-Alejo Héctor M. , López-Rodas Victoria , García-Balboa Camino , Tarín Francisco , Barrado Ana I. , Conde Estefanía , Costas Eduardo
Published: August 2021

Lithium isotopes are essential for nuclear energy, but new enrichment methods are required. In this study, we considered biotechnology as a possibility. We assessed the Li fractionation capabilities of three Chlorophyte strains: Chlamydomonas reinhardtii, Tetraselmis mediterranea, and a freshwater Chlorophyte, Desmodesmus sp. These species were cultured in Li containing media and were analysed just after inoculation and after 3, 12, and 27 days. Li mass was determined using a Inductively Coupled Plasma Mass Spectrometer, and the isotope compositions were measured on a Thermo Element XR Inductively Coupled Plasma Mass Spectrometer. The maximum Li capture was observed at day 27 with C. reinhardtii (31.66 µg/g). Desmodesmus sp. reached the greatest Li fractionation, (δ6 = 85.4‰). All strains fractionated preferentially towards 6Li. More studies are required to find fitter species and to establish the optimal conditions for Li capture and fractionation. Nevertheless, this is the first step for a microalgal nuclear biotechnology.
The Mechanisms Forming the Five–Floor Zonation of Quartz Veins: A Case Study in the Piaotang Tungsten–Tin Deposit, Southern China
Authors: Liu Xiangchong , Wang Wenlei , Zhang Dehui
Published: August 2021

It is common among many vein–type tungsten deposits in southern China that the thickness of ore veins increases from <1 cm to >1 m with increasing depth. A five–floor zonation model for the vertical trend of vein morphology was proposed in the 1960s and has been widely applied for predicting ore bodies at deeper levels, but the causative mechanisms for such a zonation remain poorly understood. The Piaotang tungsten–tin deposit, one of the birthplaces of the five–floor zonation model, is chosen as a case study for deciphering the mechanisms forming its morphological zonation of quartz veins. The vertical trend of vein morphology and its link to the W–Sn mineralization in Piaotang was quantified by statistical distributions (Weibull distribution and power law distribution) of vein thickness and ore grade data (WO3 and Sn) from the levels of 676 m to 328 m. Then, the micro–scale growth history of quartz veins was reconstructed by scanning electron microscope–cathodoluminescence (SEM–CL) imaging and in situ trace element analysis. The Weibull modulus α of vein thickness increases with increasing depth, and the fractal dimensions of both vein thickness and ore grade data (WO3 and Sn) decrease with increasing depth. Their vertical changes indicate that the fractures that bear the thick veins were well connected, facilitating fluid focusing and mineralization in mechanically stronger host rocks. Three generations (Q1–Q3) of quartz were identified from CL images, and the CL intensity of quartz is possibly controlled by the concentrations of Al and temperature. From the relative abundance of the Q1–Q3 quartz at different levels, the vertical trend of vein morphology in Piaotang was initially produced during the hydrothermal event represented by Q1 and altered by later hydrothermal events represented by Q2 and Q3. Statistical distributions of vein thickness combined with SEM–CL imaging of quartz could be combined to evaluate the mineralization potential at deeper levels.
Advantageous/Unfavorable Effect of Quercetin on the Membranes of SK-N-SH Neuroblastoma Cells
Authors: Kreczmer Barbara , Dyba Barbara , Barbasz Anna , Rudolphi-Szydło Elżbieta
Published: August 2021

Quercetin is a polyphenolic compound, the effects of which raise scientists’ doubts. The results of many experiments show that it has anticancer, antiinflammatory, and antioxidant properties, while other studies indicate its pro-oxidative and cytotoxic action. This compound can react with reactive oxygen species, and due to its chemical properties, it can be found in the hydrophobic-hydrophilic area of cells. These features of quercetin indicate that its action in cells will be associated with the modification of membranes and its participation in maintaining the redox balance. Therefore, this study distinguishes these two mechanisms and determines whether they are important for cell function. We check: (1) Whether the selected concentrations of quercetin are cytotoxic and destructive for SK-N-SH cell membranes (MTT, LDH, MDA tests) in situations with and without the applied oxidative stress; (2) what is the level of changes in the structural/mechanical properties of the lipid part of the membranes of these cells due to the presence of polyphenol molecules; and (3) whether the antioxidative action of quercetin protects the membrane against its modification. Our results show that changes in the stiffness/elasticity of the lipid part of the membrane constitute the decisive mechanism of action of quercetin, potentially influencing cellular processes whose initial stages are associated with membranes (e.g., reception of signals from the environment, transport).
Bioevaluation of Pheretima vulgaris Antithrombotic Extract, PvQ, and Isolation, Identification of Six Novel PvQ-Derived Fibrinolytic Proteases
Authors: Yang Wanqing , Wang Wenjie , Ma Yunnan , Yang Qilin , Li Pengyue , Du Shouying
Published: August 2021

Thrombosis is a disease that seriously endangers human health, with a high rate of mortality and disability. However, current treatments with thrombolytic drugs (such as recombinant tissue-plasminogen activator) and the oral anticoagulants (such as dabigatran and rivaroxaban) are reported to have a tendency of major or life-threatening bleeding, such as intracranial hemorrhage or massive gastrointestinal bleed with non-specific antidotes. In contrast, lumbrokinase is very specific to fibrin as a substrate and does not cause excessive bleeding. It can dissolve the fibrin by itself or convert plasminogen to plasmin by inducing endogenous t-PA activity to dissolve fibrin clots. Therefore, searching for potentially new therapeutic molecules from earthworms is significant. In this study, we first collected a strong fibrinolytic extract (PvQ) from the total protein of the Pheretima vulgaris with AKTA pure protein purification systems; its fibrinolytic bioactivity was verified by the fibrin plate assay and zebrafish thrombotic model of vascular damage. Furthermore, according to the cell culture model of human umbilical vein endothelial cells (HUVECs), the PvQ was proven to exhibit the ability to promote the secretion of tissue-type plasminogen activator (t-PA), which further illustrated that it has an indirect thrombolytic effect. Subsequently, extensive chromatographic techniques were applied to reveal the material basis of the extract. Fortunately, six novel earthworm fibrinolytic enzymes were obtained from the PvQ, and the primary sequences of those functional proteins were determined by LC-MS/MStranscriptome cross-identification and the Edman degradation assay. The secondary structures of these six fibrinolytic enzymes were determined by circular dichroism spectroscopy and the three-dimensional structures of these proteases were predicted by MODELLER 9.23 based on multi-template modelling. In addition, those six genes encoding blood clot-dissolving proteins were cloned from P. vulgaris by RT-PCR amplification, which further determined the accuracy of proteins primary sequences identifications and laid the foundation for subsequent heterologous expression.
The Role of Autophagy in Anti-Cancer and Health Promoting Effects of Cordycepin
Authors: Chen Yu-Ying , Chen Chun-Hsien , Lin Wei-Chen , Tung Chih-Wei , Chen Yung-Chia , Yang Shang-Hsun , Huang Bu-Miin , Chen Rong-Jane
Published: August 2021

Cordycepin is an adenosine derivative isolated from Cordyceps sinensis, which has been used as an herbal complementary and alternative medicine with various biological activities. The general anti-cancer mechanisms of cordycepin are regulated by the adenosine A3 receptor, epidermal growth factor receptor (EGFR), mitogen-activated protein kinases (MAPKs), and glycogen synthase kinase (GSK)-3β, leading to cell cycle arrest or apoptosis. Notably, cordycepin also induces autophagy to trigger cell death, inhibits tumor metastasis, and modulates the immune system. Since the dysregulation of autophagy is associated with cancers and neuron, immune, and kidney diseases, cordycepin is considered an alternative treatment because of the involvement of cordycepin in autophagic signaling. However, the profound mechanism of autophagy induction by cordycepin has never been reviewed in detail. Therefore, in this article, we reviewed the anti-cancer and health-promoting effects of cordycepin in the neurons, kidneys, and the immune system through diverse mechanisms, including autophagy induction. We also suggest that formulation changes for cordycepin could enhance its bioactivity and bioavailability and lower its toxicity for future applications. A comprehensive understanding of the autophagy mechanism would provide novel mechanistic insight into the anti-cancer and health-promoting effects of cordycepin.
Effect of ZrC Nanopowders on Enhancing the Hydro/Dehydrogenation Kinetics of MgH2 Powders
Authors: El-Eskandarany Mohamed Sherif , Ali Naser , Al-Ajmi Fahad , Banyan Mohammad
Published: August 2021

Hydrogen has been receiving great attention as an energy carrier for potential green energy applications. Hydrogen storage is one of the most crucial factors controlling the hydrogen economy and its future applications. Amongst the several options of hydrogen storage, light metal hydrides, particularly nanocrystalline magnesium hydride (MgH2), possess attractive properties, making them desired hydrogen storage materials. The present study aimed to improve the hydrogen storage properties of MgH2 upon doping with different concentrations of zirconium carbide (ZrC) nanopowders. Both MgH2 and ZrC were prepared using reactive ball milling and high-energy ball milling techniques, respectively. The as-prepared MgH2 powder was doped with ZrC (2, 5, and 7 wt%) and then high-energy-ball-milled for 25 h. During the ball milling process, ZrC powders acted as micro-milling media to reduce the MgH2 particle size to a minimal value that could not be obtained without ZrC. The as-milled nanocomposite MgH2/ZrC powders consisted of fine particles (~0.25 μm) with a nanosized grain structure of less than 7 nm. Besides, the ZrC agent led to the lowering of the decomposition temperature of MgH2 to 287 °C and the reduction in its apparent activation energy of desorption to 69 kJ/mol. Moreover, the hydrogenation/dehydrogenation kinetics of the nanocomposite MgH2/ZrC system revealed a significant improvement, as indicated by the low temperature and short time required to achieve successful uptake and release processes. This system possessed a high capability to tackle a long continuous cycle lifetime (1400 h) at low temperatures (225 °C) without showing serious degradation in its storage capacity.