bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative Stress as an Underlying Mechanism of Bacteria-Inflicted Damage to Male Gametes
Authors: Tvrdá Eva , Benko Filip , Ďuračka Michal
Published: November 2022

Bacterial infestation of the male reproductive system with subsequent effects of bacteria on the structural integrity and functional activity of male gametes has become a significant factor in the etiology of male reproductive dysfunction. Bacteria may affect male fertility either by directly interacting with structures critical for sperm survival or indirectly by triggering a local immune response, leukocytospermia or reactive oxygen species (ROS) overproduction followed by oxidative stress development. This review aims to provide an overview of the currently available knowledge on bacteriospermia-associated sperm damage with a special emphasis on oxidative mechanisms underlying sperm deterioration caused by bacterial action. At the same time, we strive to summarize readily available alternatives to prevent or counteract alterations to spermatozoa caused by bacterial colonization of semen or by oxidative stress as an accompanying phenomenon of bacteriospermia.
First Record of the Rare Species Aeromonas lusitana from Rainbow Trout (Oncorhynchus mykiss, Walbaum): Comparative Analysis with the Existing Strains
Authors: Fernández-Bravo Ana , Vega-Sánchez Vicente , Pérez-Cataluña Alba , Latif-Eugenín Fadua , Beaz-Hidalgo Roxana , Martínez-Murcia Antonio , Soriano-Vargas Edgardo , Cabrero-Martínez Omar Alejandro , Castro-Escarpulli Graciela , Figueras Maria José
Published: November 2022

The species Aeromonas lusitana was first described in 2016 with five strains recovered from untreated water and vegetables from Portugal. Since then, no further records exist of this species. During a surveillance study on the presence of Aeromonas in fish farms in Mexico, a new strain (ESV-351) of the mentioned species isolated from a rainbow trout was recovered. It was identified because it clustered phylogenetically with the type strain of A. lusitana based on the analysis of the rpoD gene sequences. In the present study, phenotypic characteristics, antimicrobial resistance profiles, and the presence of putative virulence genes of this novel strain (ESV-351) were determined in parallel to the five isolates from the original species description. Phenotypic differential characteristics exhibited by A. lusitana ESV-351 depicted an evident similarity to the characteristics exhibited by the other evaluated strains. However, the novel strain was positive for the production of indole using conventional methods, while the rest of the strains, including the type strain, were negative for its production. Furthermore, intermediate resistance to ampicillin, amoxicillin-clavulanic acid and cephalothin was detected in both the novel and the type strain. Five different virulence-related genes were detected in the novel strain and in the previously described strains, with the type strain exhibiting the highest number of virulence-related genes. In addition to this, the genome of the novel strain (ESV-351) was sequenced and compared with the genomes from the type strain (A. lusitana CECT 7828T) and other Aeromonas spp. The genomic analysis defined Aeromonas tecta as the closest species to A. lusitana with a highly similar number of predicted proteins. The genomic size, the number of protein-encoding genes and the number of different tRNAs, among other characteristics, make it possible to propose that the ESV-351 strain could potentially have the capacity to adapt to different environments. Genome comparison of the ESV-351 strain with the type strain revealed that both possess a similar sequence of the citrate synthase gene. In addition to this finding, the chromosomal region containing the citrate synthase locus of the novel strain exhibits some similarity to the chromosomal region in the genome of the A. hydrophila type strain and other known human pathogens, such as Vibrio cholerae. This could suggest a possible virulence role for the citrate synthase gene in A. lusitana (ESV-351).
Current Treatments for COVID-19: Application of Supercritical Fluids in the Manufacturing of Oral and Pulmonary Formulations
Authors: Ruiz Helga K. , Serrano Dolores R. , Calvo Lourdes , Cabañas Albertina
Published: November 2022

Even though more than two years have passed since the emergence of COVID-19, the research for novel or repositioned medicines from a natural source or chemically synthesized is still an unmet clinical need. In this review, the application of supercritical fluids to the development of novel or repurposed medicines for COVID-19 and their secondary bacterial complications will be discussed. We envision three main applications of the supercritical fluids in this field: (i) drug micronization, (ii) supercritical fluid extraction of bioactives and (iii) sterilization. The supercritical fluids micronization techniques can help to improve the aqueous solubility and oral bioavailability of drugs, and consequently, the need for lower doses to elicit the same pharmacological effects can result in the reduction in the dose administered and adverse effects. In addition, micronization between 1 and 5 µm can aid in the manufacturing of pulmonary formulations to target the drug directly to the lung. Supercritical fluids also have enormous potential in the extraction of natural bioactive compounds, which have shown remarkable efficacy against COVID-19. Finally, the successful application of supercritical fluids in the inactivation of viruses opens up an opportunity for their application in drug sterilization and in the healthcare field.
Structure, Properties, and Release Kinetics of the Polymer/Insect Repellent System Poly (l-Lactic Acid)/Ethyl Butylacetylaminopropionate (PLLA/IR3535)
Authors: Du Fanfan , Erdmann Rafael , Petzold Albrecht , Wutzler Andre , Leuteritz Andreas , Nase Michael , Androsch René
Published: November 2022

The insect repellent ethyl butylacetylaminopropionate (IR3535) was used as a functional additive for poly (l-lactic acid) (PLLA) to modify its structure and mechanical properties and achieve insect repellency. PLLA/IR3535 mixtures at various compositions were prepared via melt extrusion. In the analyzed composition range of 0 to 23 m% IR3535, PLLA and IR3535 were miscible at the length scale represented by the glass transition temperature. Addition of IR3535 resulted in a significant decrease in the glass transition temperature of PLLA, as well as in the elastic modulus, indicating its efficiency as a plasticizer. All mixtures were amorphous after extrusion, though PLLA/IR3535 extrudates with an IR3535 content between 18 and 23 m% crystallized during long-term storage at ambient temperature, due to their low glass transition temperature. Quantification of the release of IR3535 into the environment by thermogravimetric analysis at different temperatures between 50 and 100 °C allowed the estimation of the evaporation rate at lower temperatures, suggesting an extremely low release rate with a time constant of the order of magnitude of 1–2 years at body temperature.
Impact of Perfluoropentane Microdroplets Diameter and Concentration on Acoustic Droplet Vaporization Transition Efficiency and Oxygen Scavenging
Authors: Benton Rachel P. , Al Rifai Nour , Stone Kateryna , Clark Abigail , Zhang Bin , Haworth Kevin J.
Published: November 2022

Acoustic droplet vaporization is the ultrasound-mediated phase change of liquid droplets into gas microbubbles. Following the phase change, oxygen diffuses from the surrounding fluid into the microbubble. An in vitro model was used to study the effects of droplet diameter, the presence of an ultrasound contrast agent, ultrasound duty cycle, and droplet concentration on the magnitude of oxygen scavenging in oxygenated deionized water. Perfluoropentane droplets were manufactured through a microfluidic approach at nominal diameters of 1, 3, 5, 7, 9, and 12 µm and studied at concentrations varying from 5.1 × 10−5 to 6.3 × 10−3 mL/mL. Droplets were exposed to an ultrasound transduced by an EkoSonicTM catheter (2.35 MHz, 47 W, and duty cycles of 1.70%, 2.34%, or 3.79%). Oxygen scavenging and the total volume of perfluoropentane that phase-transitioned increased with droplet concentration. The ADV transition efficiency decreased with increasing droplet concentration. The increasing duty cycle resulted in statistically significant increases in oxygen scavenging for 1, 3, 5, and 7 µm droplets, although the increase was smaller than when the droplet diameter or concentration were increased. Under the ultrasound conditions tested, droplet diameter and concentration had the greatest impact on the amount of ADV and subsequent oxygen scavenging occurred, which should be considered when using ADV-mediated oxygen scavenging in therapeutic ultrasounds.
Microrobot with Gyroid Surface and Gold Nanostar for High Drug Loading and Near-Infrared-Triggered Chemo-Photothermal Therapy
Authors: Zheng Shirong , Hoang Manh Cuong , Nguyen Van Du , Go Gwangjun , Nan Minghui , Darmawan Bobby Aditya , Kim Seokjae , Im Seung-hyun , Lee Taeksu , Bang Doyeon , Park Jong-Oh , Choi Eunpyo
Published: November 2022

The use of untethered microrobots for precise synergistic anticancer drug delivery and controlled release has attracted attention over the past decade. A high surface area of the microrobot is desirable to achieve greater therapeutic effect by increasing the drug load. Therefore, various nano- or microporous microrobot structures have been developed to load more drugs. However, as most porous structures are not interconnected deep inside, the drug-loading efficiency may be reduced. Here, we propose a magnetically guided helical microrobot with a Gyroid surface for high drug-loading efficiency and precise drug delivery. All spaces inside the proposed microrobot are interconnected, thereby enabling drug loading deep inside the structure. Moreover, we introduce gold nanostars on the microrobot structure for near-infrared-induced photothermal therapy and triggering drug release. The results of this study encourage further exploration of a high loading efficiency in cell-based therapeutics, such as stem cells or immune cells, for microrobot-based drug-delivery systems.
Scarcity as an Alibi: On the False Ethical Discussions about the War on COVID-19
Authors: Ribeiro Renato Janine
Published: November 2022

Occasionally, doctors and health providers have to choose whom they save from death and this is an extremely hard decision to take. Here, I work on what I deem to be a crucial caveat: scarcity of resources should never be used as an alibi for bad, and sometimes wicked, public policies. In other words, if scarcity is somewhat produced or at least induced, it should never serve as a pretext to put the blame or the responsibility on medical doctors, nurses and other people who are at the front of the war against COVID-19. During the COVID-19 pandemic, an ethical question was often raised: if resources are scarce (and they often have been), whom should you prioritize? Should we protect first of all those who are young and can then have a long life before them? Or should we rather prioritize those who have rendered important services to health, or broadly to mankind, and could, therefore, bring other good results to society? This discussion is of course important, but it leaves aside something more fundamental: the fact that resources are not simply scarce, they have been made scarce in the last years by a series of public policies nourished by an economic view that sacrificed social welfare on behalf of neoliberal beliefs.
Photoprotective Effects of Selected Polyphenols and Antioxidants on Naproxen Photodegradability in the Solid-State
Authors: Kawabata Kohei , Miyoshi Ayano , Nishi Hiroyuki
Published: November 2022

Photostabilization is an important methodology to ensure both the quality and quantity of photodegradable pharmaceuticals. The purpose of our study is to develop a photostabilization strategy focused on the addition of photostabilizers. In this study, the protective effects of selected polyphenols and antioxidants on naproxen (NPX) photodegradation in the solid state were evaluated. Residual amounts of NPX were determined by high-performance liquid chromatography (HPLC), and the protective effects of tested additives on NPX photodegradation induced by ultraviolet light (UV) irradiation were evaluated. As a result, quercetin, curcumin, and resveratrol suppressed NPX photodegradation completely. When they were mixed with NPX, the residual amounts of NPX after UV irradiation were significantly higher compared to that without additives, and comparable to those of their control samples. In addition, to clarify the mechanisms of the highly protective effects of these additives on NPX photodegradation, their antioxidative potencies, and UV filtering potencies were determined. There was no correlation between photoprotective effects and antioxidative potencies among selected polyphenols and antioxidants although photoprotective additives showed more significant UV absorption compared to NPX. From these results, it is clarified that a higher UV filtering activity is necessary for a better photostabilizer to photodegradable pharmaceuticals in the solid state.
Compression of the Synchrotron Mössbauer X-ray Photon Waveform in an Oscillating Resonant Absorber
Authors: Khairulin Ilias R. , Radeonychev Yevgeny V. , Kocharovskaya Olga
Published: November 2022

A technique to transform the waveform of a 14.4 keV photon (time dependence of the photon detection probability or, equivalently, the intensity of the single-photon wave packet) into a regular sequence of short, nearly bandwidth-limited pulses with a controlled number of pulses is proposed. It is based on coherent forward scattering of single X-ray photons from a synchrotron Mössbauer source (SMS) in an optically thick, vibrating, recoilless 57Fe resonant absorber. The possibility of compressing the waveform of an SMS photon into a single short bell-shaped pulse is predicted. The experiment is proposed for compressing a 100 ns duration 14.4 keV single-photon wave packet produced by SMS at the European Synchrotron Radiation Facility (ESRF) into a single bell-shaped pulse of less than 20 ns duration and more than twice the peak intensity. Such single-photon coherent pulses are promising for applications in the fast-developing field of X-ray quantum optics, including possible implementation of quantum memory.
Longer Duration of Active Oil Biosynthesis during Seed Development Is Crucial for High Oil Yield—Lessons from Genome-Wide In Silico Mining and RNA-Seq Validation in Sesame
Authors: Nawade Bhagwat , Kumar Ajay , Maurya Rasna , Subramani Rajkumar , Yadav Rashmi , Singh Kuldeep , Rangan Parimalan
Published: November 2022

Sesame, one of the ancient oil crops, is an important oilseed due to its nutritionally rich seeds with high protein content. Genomic scale information for sesame has become available in the public databases in recent years. The genes and their families involved in oil biosynthesis in sesame are less studied than in other oilseed crops. Therefore, we retrieved a total of 69 genes and their translated amino acid sequences, associated with gene families linked to the oil biosynthetic pathway. Genome-wide in silico mining helped identify key regulatory genes for oil biosynthesis, though the findings require functional validation. Comparing sequences of the SiSAD (stearoyl-acyl carrier protein (ACP)-desaturase) coding genes with known SADs helped identify two SiSAD family members that may be palmitoyl-ACP-specific. Based on homology with lysophosphatidic acid acyltransferase (LPAAT) sequences, an uncharacterized gene has been identified as SiLPAAT1. Identified key regulatory genes associated with high oil content were also validated using publicly available transcriptome datasets of genotypes contrasting for oil content at different developmental stages. Our study provides evidence that a longer duration of active oil biosynthesis is crucial for high oil accumulation during seed development. This underscores the importance of early onset of oil biosynthesis in developing seeds. Up-regulating, identified key regulatory genes of oil biosynthesis during early onset of seed development, should help increase oil yields.
Foliar P Application Cannot Fully Restore Photosynthetic Capacity, P Nutrient Status, and Growth of P Deficient Maize (Zea mays L.)
Authors: Henningsen Jon Niklas , Görlach Bruno Maximilian , Fernández Victoria , Dölger Jasper Lauritz , Buhk Andreas , Mühling Karl Hermann
Published: November 2022

The essential plant nutrient phosphorus (P) is key for numerous structures and processes in crops and its deficiency can severely restrict yield and quality. As soil P availability for plant uptake is often limited, foliar P application can be an alternative means of supplying P to the plants during the growth period. This study was aimed at investigating the effect of foliar P application on photosynthetic parameters, P nutritional status, and growth of P deficient maize over time. Plants of Zea mays L. cv. Keops were grown with deficient and sufficient amounts of P in hydroponics. Foliar P treatments were applied to P deficient plants and several physiological parameters were monitored for 21 days. The variables measured were leaf gas exchange parameters, SPAD values, foliar P absorption, re-translocation rates, and plant biomass production. Foliar P application significantly increased CO2-assimilation and SPAD values and additionally enhanced biomass production in all plant components. Elemental analysis revealed increased tissue P concentrations following foliar P application compared to P deficient plants. While increased growth of P-deficient plants was steadily promoted by foliar P spraying for the entire experimental period, the positive effect on CO2 assimilation and P concentration was transient and vanished some days after the foliar treatment. P deficiency markedly impaired the efficiency of physiological processes of maize plants. As a conclusion, foliar P fertilisation improved physiological and agronomical plant parameters over time, but failed to restore plant functionality of P deficient maize plants during a prolonged experimental period.
New Genomic Regions Identified for Resistance to Spot Blotch and Terminal Heat Stress in an Interspecific Population of Triticum aestivum and T. spelta
Authors: Navathe Sudhir , Pandey Ajeet Kumar , Sharma Sandeep , Chand Ramesh , Mishra Vinod Kumar , Kumar Dinesh , Jaiswal Sarika , Iquebal Mir Asif , Govindan Velu , Joshi Arun Kumar , Singh Pawan Kumar
Published: November 2022

Wheat is one of the most widely grown and consumed food crops in the world. Spot blotch and terminal heat stress are the two significant constraints mainly in the Indo–Gangetic plains of South Asia. The study was undertaken using 185 recombinant lines (RILs) derived from the interspecific hybridization of ‘Triticum aestivum (HUW234) × T. spelta (H+26)’ to reveal genomic regions associated with tolerance to combined stress to spot blotch and terminal heat. Different physiological (NDVI, canopy temperature, leaf chlorophyll) and grain traits (TGW, grain size) were observed under stressed (spot blotch, terminal heat) and non-stressed environments. The mean maturity duration of RILs under combined stress was reduced by 12 days, whereas the normalized difference vegetation index (NDVI) was 46.03%. Similarly, the grain size was depleted under combined stress by 32.23% and thousand kernel weight (TKW) by 27.56% due to spot blotch and terminal heat stress, respectively. The genetic analysis using 6734 SNP markers identified 37 significant loci for the area under the disease progress curve (AUDPC) and NDVI. The genome-wide functional annotation of the SNP markers revealed gene functions such as plant chitinases, NB-ARC and NBS-LRR, and the peroxidase superfamily Cytochrome P450 have a positive role in the resistance through a hypersensitive response. Zinc finger domains, cysteine protease coding gene, F-box protein, ubiquitin, and associated proteins, play a substantial role in the combined stress of spot blotch and terminal heat in bread wheat, according to genomic domains ascribed to them. The study also highlights T. speltoides as a source of resistance to spot blotch and terminal heat tolerance.
Antifungal Potential of Canarian Plant Extracts against High-Risk Phytopathogens
Authors: Reyes Carolina P. , Sabina Samuel Rodríguez , López-Cabeza Rocío , Montelongo Cristina G. , Giménez Cristina , Jiménez Ignacio A. , Cabrera Raimundo , Bazzochi Isabel L.
Published: November 2022

Phytopathogens are responsible for great losses in agriculture. In particular, Fusarium, Alternaria and Botrytis are fungal diseases that affect crops worldwide. In the search for eco-friendly solutions to pest control, plants and their chemo-biodiversity are promising sources of biopesticides for integrated pest management. The aim of the present study is to report the evaluation of sixteen plant species from the Canary Islands Archipelago against the phytopathogenic fungi Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata. The plants were selected on the basis of their traditional uses in medicine and/or pest control, as well as on scientific studies reporting their uses in crop protection. Their growth inhibition (% I), in an in vitro test-assay on mycelium, was used to identify six ethanolic plant extracts displaying activity (% I > 30% at 1 mg/mL) against at least one of the assayed fungi. The most effective plant extracts were further fractionated by liquid–liquid partition, using solvents of increasing polarity. This procedure led to an improvement of the bioactivity against the phytopathogens, even affecting the hexane fraction from S. canariensis and achieving an 83.93% of growth inhibition at 0.5 mg/mL on B. cinerea. These findings identified five plant-derived extracts as potential candidates for the future development of new biofungicides, which could be applied in integrated pest management.
Effect of Germination and Illumination on Melatonin and Its Metabolites, Phenolic Content, and Antioxidant Activity in Mung Bean Sprouts
Authors: Siriparu Pimolwan , Panyatip Panyada , Pota Thanawat , Ratha Juthamat , Yongram Chawalit , Srisongkram Tarapong , Sungthong Bunleu , Puthongking Ploenthip
Published: November 2022

Mung bean (Vigna radiata L.) sprouts are increasingly consumed and have become part of a healthy diet. The sprouts are composed of proteins, carbohydrates, and biochemical compounds. During germination, the phytochemical compounds are significantly elevated, especially under stress conditions such as salinity, drought, extreme temperature, and illumination. The present study examined the effects of light and germination time on the bioactive compounds in mung bean sprout extracts. Mung bean seeds were sprouted under different light exposure conditions, and the phytochemical composition and antioxidant activity of sprout extracts were determined compared to seeds. The results show that tryptophan sharply decreased during germination. On the contrary, melatonin, polyphenols, and total phenolic content (TPC) were elevated with increased germination time, correlated with increased antioxidant activity. Sprouts germinated in the dark presented higher levels of melatonin and TPC compared with those germinated under 12 h light exposure (3.6- and 1.5-fold, respectively). In conclusion, germination can enhance valuable phytochemicals and antioxidant activity of mung bean sprouts. Mung bean sprouts may be a good alternative functional food for promoting human health.
Phytochemicals and Inflammation: Is Bitter Better?
Authors: Dragoș Dorin , Petran Madalina , Gradinaru Teodora-Cristiana , Gilca Marilena
Published: November 2022

The taste of a herb influences its use in traditional medicine. A molecular basis for the taste-based patterns ruling the distribution of herbal (ethno) pharmacological activities may not be excluded. This study investigated the potential correlations between the anti-inflammatory activity (AIA) and the phytocompound taste and/or its chemical class. The study relies on information gathered by an extensive literature (articles, books, databases) search and made public as PlantMolecularTasteDB. Out of a total of 1527 phytotastants with reliably documented taste and structure available in PlantMolecularTasteDB, 592 (for each of which at least 40 hits were found on PubMed searches) were included in the statistical analysis. A list of 1836 putative molecular targets of these phytotastants was afterwards generated with SwissTargetPrediction tool. These targets were systematically evaluated for their potential role in inflammation using an international databases search. The correlations between phytochemical taste and AIA, between chemical class and AIA, and between the taste and the number of inflammation related targets were statistically analyzed. Phytochemical taste may be a better predictor of AIA than the chemical class. Bitter phytocompounds have a higher probability of exerting AIA when compared with otherwise phytotastants. Moreover, bitter phytotastants act upon more inflammation related targets than non-bitter tasting compounds.
Application of Infrared Spectroscopy in Research on Aging of Silicone Rubber in Harsh Environment
Authors: Zhang Zhijin , Liang Tian , Jiang Zhenglong , Jiang Xingliang , Hu Jianlin , Pang Guohui
Published: November 2022

Polymer insulators using silicone rubber materials as sheds and sheaths are widely used in power systems to replace traditional porcelain and glass insulators which are heavy, inconvenient to install, and prone to pollution flashover. However, in recent years, polymer insulators that have been operating in harsh outdoor environments for many years have experienced different degrees of aging. The aging degree and aging products of silicone rubber are the focus of research. Fourier transform infrared spectroscopy (FTIR) is a technical method to analyze the internal molecular bonds and functional groups of materials, and it is often used to study the aging degree and aging products of silicone rubber. In this paper, the aging characteristics of silicone rubber samples in a high altitude area, salt fog environment, and acid environment were studied by FTIR. The results showed that the silicone rubber in a harsh environment, such as strong radiation, salt fog, and acid fog was degraded to some extent, and its main chain was cut off, the degree of polymerization was reduced, and the content of hydrophobic functional groups was reduced. Infrared spectroscopy can be used to analyze the aging phenomenon of polymers.
Advanced Protective Films Based on Binary ZnO-NiO@polyaniline Nanocomposite for Acidic Chloride Steel Corrosion: An Integrated Study of Theoretical and Practical Investigations
Authors: Al-Masoud May Ahmed , Khalaf Mai M. , Heakal Fakiha El-Taib , Gouda Mohamed , Mohamed Ibrahim M. A. , Shalabi Kamal , El-Lateef Hany M. Abd
Published: November 2022

Due to their thermal stability characteristics, polymer/composite materials have typically been employed as corrosion inhibitors in a variety of industries, including the maritime, oil, and engineering sectors. Herein, protective films based on binary ZnO-NiO@polyaniline (ZnNiO@PANE) nanocomposite were intended with a respectable yield. The produced nanocomposite was described using a variety of spectroscopic characterization methods, including dynamic light scattering (DLS), ultraviolet–visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) approaches, in addition to other physicochemical methods, including X-ray powder diffraction (XRD), transmission Electron Microscopy (TEM), field emission scanning electron microscopy (FESEM), and selected area electron diffraction (SAED). By using open-circuit potentials (OCP) vs. time, electrochemical impedance spectroscopic (EIS), and potentiodynamic polarization (PDP) methods, the inhibitory effects of individual PANE and ZnNiO@PANE on the mild steel alloy corrosion in HCl/NaCl solution were assessed. The ZnNiO@PANE composite performed as mixed-type inhibitors, according to PDP findings. PANE polymer and ZnNiO@PANE composite at an optimal dose of 200 mg/L each produced protective abilities of 84.64% and 97.89%, respectively. The Langmuir isotherm model is used to explain the adsorption of ZnNiO@PANE onto MS alloy. DFT calculations showed that the prepared materials’ efficiency accurately reflects their ability to contribute electrons, whereas Monte Carlo (MC) simulations showed that the suitability and extent of adsorption of the ZnNiO@PANE molecule at the metal interface determine the materials’ corrosion protection process.
Maximizing the Application of RAP in Asphalt Concrete Pavements and Its Long-Term Performance: A Review
Authors: Zhang Jialin , Sesay Taiwo , You Qinglong , Jing Hongjun
Published: November 2022

The use of recycled asphalt pavement (RAP) materials in asphalt concrete pavements (ACP) brings significant cost and environmental benefits. In practice, however, the amount of RAP readily available far exceeds the amount being utilized in ACPs, which still leaves the problem of excess RAP in the environment partially solved. Additionally, ACPs containing RAP materials (i.e., RAP-ACPs) can still be landfilled after they have reached the end of their useful life, which may restore the original environmental waste problem. To address these, researchers have demonstrated different ways to maximize the application of RAP in ACPs. Among them, the use of RAP in pavement preventive maintenance (PPM) treatments and the repeated recycling of RAP-ACPs (i.e., RnAP) are specifically discussed in this review. It is envisaged that, by promoting these two practices, the application and benefits of RAP can be further maximized to improve sustainability. This review also discusses the long-term behavior of RAP-ACP, which is crucial to inspire confidence in the wider application of RAP in ACP. Studies on RAP-PPM have shown that virgin PPM treatments can successfully accommodate RAP materials by adjusting their mix design. So far, research on RnAP has been limited to how multiple-recycling affects the performance properties of the blends, showing improvements in rutting resistance and moisture susceptibility but little effect on linear viscoelasticity and cracking. Overall, the lack of sufficient research is considered to be the biggest challenge in facilitating the implementation of these two sustainable RAP technologies. Little or nothing is known about the bonding mechanisms between RAP and fresh PPM binders, the molecular and chemical changes in RnAP binders, or the functional performance characteristics, actual pavement performance, and long-term performance of both RAP-PPM and RnAP blends. An understanding of these aspects is very relevant to maximize and continue the beneficial reuse of RAP in ACPs while safeguarding human and environmental health.
Multi-Functional Materials Based on Cu-Doped TiO2 Ceramic Fibers with Enhanced Pseudocapacitive Performances and Their Dielectric Characteristics
Authors: Pascariu Petronela , Homocianu Mihaela , Vacareanu Loredana , Asandulesa Mihai
Published: November 2022

In this work, pure TiO2 and Cu (0.5, 1, 2%)-doped TiO2 composites prepared by electrospinning technique followed by calcination at 900 °C, and having high pseudocapacitive and dielectric characteristics were reported. These nanocomposites were characterized by scanning electron microscopy, X-ray diffraction, and dynamic water sorption vapor measurements. The structural characterization of these nanostructures highlighted good crystallinity including only the rutile phase. The electrochemical characteristics were investigated by cyclic voltammetry and galvanostatic charge–discharge measurements, which were performed in a KOH electrolyte solution. Among the Cu-doped TiO2 nanostructures that were prepared, the one containing 0.5% Cu exhibited superior electrochemical properties, including high specific gravimetric capacitance of 1183 F·g−1, specific capacitance of 664 F·g−1, energy density of 45.20 Wh·kg−1, high power density of 723.14 W·kg−1, and capacitance retention of about 94% after 100 cycles. The dielectric investigation shows good dielectric properties for all materials, where the dielectric constant and the dielectric loss decreased with the frequency increase. Thus, all the interconnected studies proved that these new materials show manifold ability and real applicative potential as pseudocapacitors and high-performance dielectrics. Future work and perspectives are anticipated for characterizing electrochemical and dielectric properties for materials including larger amounts of Cu dopant.
Impact of the Morphology of Electrospun Lignin/Ethylcellulose Nanostructures on Their Capacity to Thicken Castor Oil
Authors: Borrego María , Martín-Alfonso José E. , Valencia Concepción , Sánchez M. Carmen , Franco José M.
Published: November 2022

This study reports on a novel strategy for manufacturing thickened gel-like castor oil formulations by dispersing electrospun lignin/ethylcellulose nanostructures. These thickened formulations were rheologically and tribologically evaluated with the aim of being proposed as alternative ecofriendly lubricating greases. Low-sulfonate kraft lignin (LSL) and ethylcellulose (EC) were dissolved in a DMAc:THF mixture at different concentrations (8, 10, and 15 wt.%) and LSL:EC ratios (50:50, 70:30, and 90:10) and subjected to electrospinning. The resulting electrospun nanostructures were morphologically characterized. EC acting as the cospinning polymer improved both LSL spinnability and the oil structuring ability. Solutions with a high lignin content achieved microsized particles connected by fibrils, whereas solutions with a high EC content (50:50 ratio) and LSL/EC total concentration (10 and 15 wt.%) yielded beaded or bead-free nanofibers, due to enhanced extensional viscoelastic properties and nonNewtonian characteristics. The gel-like properties of electrospun nanostructure dispersions in castor oil were strengthened with the nanostructure concentration and the EC:LSL ratio, as a result of the formation of a more interconnected fiber network. The oleodispersions studied exhibited a satisfactory frictional response in a tribological contact, with friction coefficient values that were comparable to those achieved with traditional lithium-lubricating greases.
Experimental Investigation on the Mechanical and Physical Properties of Glass/Jute Hybrid Laminates
Authors: Dias Thaís da Costa , Silva Amanda Albertin Xavier da , Tonatto Maikson Luiz Passaia , Amico Sandro Campos
Published: November 2022

Natural fibres have been partly substituting synthetic fibres in polymer composites due to their renewable character and many other advantages, and sometimes, they can be hybridized into a single composite for a better combination of properties. This work aims to study the effect of hybridization and stacking sequence on the mechanical and physical properties of the glass/jute laminates. For that, pure jute, pure glass and glass/jute hybrids were manufactured by vacuum infusion process using orthophthalic polyester resin. The composites were characterized via C-scan analysis, density, volume fraction of constituents and optical microscopy analyses. Mechanical properties were obtained from tensile, compression and shear tests. The longitudinal properties were higher than transverse properties for all laminates. The hybrids presented intermediate density and mechanical properties compared to pure glass and pure jute laminates. The hybrids produced similar density and tensile modulus, but with small differences in tensile strength and compressive strength which were justified based on variations in resin and void content due to the influence of the stacking sequence (glass/jute interlayer regions). In addition, the pure glass and the hybrid laminates displayed acceptable failure morphology in the in-plane shear test, but not the pure jute laminate.
Flexible Polyurethane Foams Reinforced by Functionalized Polyhedral Oligomeric Silsesquioxanes: Structural Characteristics and Evaluation of Thermal/Flammability Properties
Authors: Hebda Edyta , Bukowczan Artur , Michałowski Sławomir , Pielichowski Krzysztof
Published: November 2022

In this work, we report on flexible toluene diisocyanate (TDI)-based polyurethane foams (FPUFs) chemically modified by POSS moieties, i.e., octa (3-hydroxy-3-methylbutyldimethylsiloxy) POSS (OCTA-POSS) and 1,2-propanediolizo-butyl POSS (PHI-POSS). The influence of silsesquioxane on the PU foaming process, structure, morphology, physicochemical, and mechanical properties, as well as flammability, was examined. FT-IR analysis provided evidence for the chemical incorporation of the nanofiller into the foam structure. It was found that the addition of POSS increases the apparent density of the foam and its compressive strength. The XRD and SEM-EDS techniques showed the uniform distribution of POSS in the FPUF with agglomeration depending on the kind and content of the introduced POSS moieties. The analysis of the thermogravimetric and microcalorimetry data revealed an improved resistance to the burning of FPUFs containing reactive POSS, as evidenced by the reduced rate of heat release (HRR). Importantly, the mechanical properties tests showed that the incorporation of silsesquioxane nanoparticles into the polyurethane structure via covalent bonds strengthens the foam integrity.
Flexible Investment Casting Wax Patterns for 3D-Printing: Their Rheological and Mechanical Characterizations
Authors: Szabó László , Deák György , Nyul Dávid , Kéki Sándor
Published: November 2022

The mechanical and rheological characterizations of flexible investment casting patterns capable of 3D printing are reported. The wax pattern was composed of microcrystalline hydrocarbon wax (DMW7478), Piccotex 75 (a copolymer of α–methyl–styrene and vinyl toluene with a 75/25 molar ratio, respectively) and Escorene (a copolymer of ethylene and vinyl acetate with a 72/28 mass ratio, respectively). It was found that in order to obtain a wax pattern with appreciable mechanical properties, the content of the microcrystalline hydrocarbon wax in these blends should not exceed 30% (m/m). Thus, a series of patterns with 28% (m/m) wax and varying Piccotex and Escorene contents spanning from 0 to 72% (m/m) was prepared. The dependence of the dynamic viscosities of the wax patterns on the composition was described using a stretched exponential model, whereas their variations with the temperature were interpreted in terms of the Arrhenius–Guzman equation. Furthermore, the slopes of the lines fitted to the viscosity versus temperature curves at the pour point decreased linearly with the Piccotex content. Non-Newtonian changes in the shear stress with the shear rate and shear stress crystallization were observed at temperatures near the pour points. The mechanical properties were evaluated using the uniaxial tensile mode and by three-point bending experiments. It was found that the stress (σ) versus the relative elongation (ε) curves can effectively be rendered by means of the standard linear solid (SLS) viscoelastic model. In addition, it was also established that the Young’s modulus varied according to a sigmoid-type curve with the piccotex content, while the yield stress decreased linearly with the concentration of Piccotex. In addition, based on the spooling suitability and printability, the patterns were rated and it was found that the most appropriate wax pattern compositions for 3D printing were those which contained 30% (m/m) and 35% (m/m) Piccotex.
Spin-Trapping Analysis of the Thermal Degradation Reaction of Polyamide 66
Authors: Kurima Akihiro , Kinashi Kenji , Sakai Wataru , Tsutsumi Naoto
Published: November 2022

The radical mechanisms of the thermal degradation of polyamide 66 (PA66) occurring under a vacuum at a temperature range between 80 °C and 240 °C (which includes the temperature of practical applications) were investigated using a spin-trapping electron spin resonance (ST-ESR) technique, as well as FTIR, TG-DTA, and GPC methods. No significant weight loss and no sign of thermal degradation are observed at this temperature range under oxygen-free conditions, but a slight production of secondary amine groups is confirmed by FTIR. GPC analysis shows a small degradation by the main chain scission. ST-ESR analysis reveals two intermediate radicals which are produced in the thermal degradation of PA66: (a) a ●CH2− radical generated by main chain scission and (b) a −●CH− radical generated by hydrogen abstraction from the methylene group of the main chain. The ST-ESR result does not directly confirm that a −NH−●CH− radical is produced, although this reaction has been previously inferred as the initiation reaction of the thermal degradation of PA; however, the presence of −●CH− radicals strongly suggests the occurrence of this initiation reaction, which takes place on the α-carbon next to the NH group. The ST-ESR analysis reveals very small levels of reaction, which cannot be observed by common analytical methods such as FTIR and NMR.
Experimental Study on Compressive Behavior of Concrete Cylinders Confined by a Novel Hybrid Fiber-Reinforced Polymer Spiral
Authors: Tang Yu , Lu Xiaowan , Wei Yang , Hou Shitong
Published: November 2022

Modern fiber-reinforced polymer (FRP)-reinforced concrete structures are excepted to achieve superior mechanical performances and long service lives, even in harsh service environments. Hybrid FRP material could potentially meet this goal with its relatively high strength-to-cost ratio. This paper presents an experimental study on the compressive behavior of concrete cylinders confined by a novel hybrid fiber-reinforced polymer (HFRP) spiral. Nine types, forming a total of 27 confined or non-confined concrete cylinders, were subjected to an axial compressive-loading test. Concrete cylinders confined either with different spiral types or different spiral spacings were comparatively studied in the experiment. The results showed that the compressive failure modes and the stress–strain relationships of the HFRP-spiral-confined cylinders were similar to those of basalt-fiber-reinforced polymer (BFRP)-spiral-confined cylinders. The actual fracture strain of the HFRP spiral (tested as a single rod) was larger than that of the corresponding carbon-fiber-reinforced polymer (CFRP) bar, indicating the advantageous composite effect of the HFRP spiral. The maximum strain of the HFRP spiral reached over 70% of its ultimate strain in the cylinders compared to the BFRP spiral, which only reached 50%. Most of the existing models overestimated the ultimate stress and strain of the HFRP-spiral-confined cylinders. Wu’s model was proved to be the most accurate model, yet proper modification was required for predicting the peak strain of the HFRP-confined cylinders.
Preparation of 3D Printed Polylactic Acid/Bacterial Cellulose Composite Scaffold for Tissue Engineering Applications
Authors: Wu Yadong , Wang Yunfeng , Wang Fang , Huang Yudong , He Jinmei
Published: November 2022

Bacterial cellulose (BC) has become a universal biomaterial owing to its intrinsic properties. BC fibers are composed of microfibers with a diameter of 3–4 nm into fiber bundles with a thickness of 40–60 nm, and interweave with each other to form a well-developed ultra-fine network structure. Polylactic acid (PLA) has good mechanical properties and excellent biocompatibility and biodegradability. Therefore, PLA has been widely applied in tissue engineering. Addressed herein is a novel type of PLA/BC (PLA/BC) composite scaffold prepared by 3D printing (3D), 3D modeling of the required porous membrane material support established in the computer, and decomposition of the model into 5 layer 20 μM sheets. The range of PLA loadings assessed in this work was 1.0 wt.%, 1.5 wt.%, and 2.0 wt.%, and its physicochemical properties and biological properties were characterized and evaluated. Tensile strength of PLA/BC composite scaffolds increased to 66.49 MPa compared to that of a pure BC film (25.61 MPa). Hydrophilicity was tunable with the amount of added PLA. In this paper, the effects of 3D round hole and stripe surface topology on cell growth behavior were characterized. Schwann cells (SCs) adhered to the surface of the 3D composite membrane successfully, and their proliferation rate on the surface of the regular circular pore and stripe structure was better than that of the smooth surface. Erythrocyte fixation and platelet adhesion experiments showed that the 3D composite scaffold had excellent blood compatibility. Further degradation studies showed that loose structures appeared after 1 week, and structural defects began after 3 weeks. The in vitro degradation results showed that the degradation rate of the BC membrane in simulated body fluid after 6 weeks was 14.38%, while the degradation rate of the PLA/BC composite scaffold was 18.75%.
Decision-Making Model of Mechanical Components in a Lean–Green Manufacturing System Based on Carbon Benefit and Its Application
Authors: Zhu Xiaoyong , Xiao Yongmao , Xiao Gongwei
Published: November 2022

The key to achieving low-carbon manufacturing is to effectively reduce the carbon emissions of production systems and improve carbon benefits. The use of lean and green tools aids in measuring the added value of products, and increases the efficiency and sustainability of production systems. To address this problem and verify that the synergetic relationship between lean and green innovation increases the efficiency and sustainability in production systems, a new low-carbon manufacturing evaluation indicator—carbon benefit—in lean manufacturing systems was discussed. A low-carbon decision-making model of multiple processes aiming at carbon benefit maximization, as well as the dynamic characteristics of carbon benefit and sustainable process improvements in a lean production system, was established. A case study of a certain satellite dish parts manufacturing line was introduced to analyze and verify the feasibility of the proposed model. After improvement, the processing time of unit parts was reduced from 63 s to 54 s. The workstations were optimized again according to the lean–green manufacturing concept, and the number was reduced by 37.5%. The process was recombined and reduced from 8 to 5 to achieve continuous-flow processing. This reduced the distance by 77 m, and at the same time, the number of operating personnel was reduced, and the after-improvement carbon efficiency increased from 12.98 s/kg CO2e to 36.33 s/kg CO2e in comparison with that before the improvement. The carbon benefit after improvement was 193.92% higher than that before the improvement.