bluuebunny/crossref_metadata_2025 huggingface dataset:
Carboxylation Capacity Can Limit C3 Photosynthesis at Elevated CO2 throughout Diurnal Cycles
Authors: Bunce James
Published: December 2021

The response of carbon fixation in C3 plants to elevated CO2 is relatively larger when photosynthesis is limited by carboxylation capacity (VC) than when limited by electron transport (J). Recent experiments under controlled, steady-state conditions have shown that photosynthesis at elevated CO2 may be limited by VC even at limiting PPFD. These experiments were designed to test whether this also occurs in dynamic field environments. Leaf gas exchange was recorded every 5 min using two identical instruments both attached to the same leaf. The CO2 concentration in one instrument was controlled at 400 μmol mol−1 and one at 600 μmol mol−1. Leaves were exposed to ambient sunlight outdoors, and cuvette air temperatures tracked ambient outside air temperature. The water content of air in the leaf cuvettes was kept close to that of the ambient air. These measurements were conducted on multiple, mostly clear days for each of three species, Glycine max, Lablab purpureus, and Hemerocallis fulva. The results indicated that in all species, photosynthesis was limited by VC rather than J at both ambient and elevated CO2 both at high midday PPFDs and also at limiting PPFDs in the early morning and late afternoon. During brief reductions in PPFD due to midday clouds, photosynthesis became limited by J. The net result of the apparent deactivation of Rubisco at low PPFD was that the relative stimulation of diurnal carbon fixation at elevated CO2 was larger than would be predicted when assuming limitation of photosynthesis by J at low PPFD.
Contrasting Hydraulic Efficiency and Photosynthesis Strategy in Differential Successional Stages of a Subtropical Forest in a Karst Region
Authors: Wu Guilin , Chen Dexiang , Zhou Zhang
Published: December 2021

Understanding the successional process from a disturbed forest to a mature forest is essential for species recovery and conservation initiatives. The resource acquisition and drought tolerance of plants can be instructive to predictions of species abundance and distribution for different forests. However, they have not been adequately tested at different successional stages in karst regions. Here, we selected seven dominant species in an early-succession forest and 17 species in a late-succession forest in a karst region of southwestern China. Resource acquisition-related traits such as hydraulic conductivity and photosynthetic rate, and drought tolerance-related traits, including turgor loss point and wood density, were measured. We found that species in the early-succession forest had a higher hydraulic conductance and photosynthetic rate than those in the late-succession forest, while leaf water potential at turgor loss point and wood density showed nonsignificant differences between the two forests. In addition, we observed a significant negative relationship between photosynthetic rate and drought tolerance in the early-succession forest, which was not identified in late-succession forests. Our study indicates that resource acquisition rather than drought tolerance was the key factor explaining plant distributions in forests at different successional stages in karst regions. We also suggest that the resource acquisition and drought tolerance trade-off hypothesis is not always supported for karst region species. Our study could inform about the design of species replacements in successional forests and provide forest management and restoration guidelines for karst regions.
Anatomical and Chemical Characterization of Ulmus Species from South Korea
Authors: Park Woo-Sung , Kim Hye-Jin , Khalil Atif Ali Khan , Kang Dong-Min , Akter Kazi-Marjahan , Kwon Ji-Min , Kim Yong-ung , Piao Xiang-Lan , Koo Kyung-Ah , Ahn Mi-Jeong
Published: December 2021

Ulmus species (Ulmaceae) are large deciduous trees distributed throughout Korea. Although their root and stem bark have been used to treat gastrointestinal diseases and wounds in folk medicine, commercial products are consumed without any standardization. Therefore, we examined anatomical and chemical differences among five Ulmus species in South Korea. Transverse sections of leaf, stem, and root barks were examined under a microscope to elucidate anatomical differences. Stem and root bark exhibited characteristic medullary ray and secretary canal size. Leaf surface, petiole, and midrib exhibited characteristic inner morphologies including stomatal size, parenchyma, and epidermal cell diameter, as well as ratio of vascular bundle thickness to diameter among the samples. Orthogonal projections to latent structures discriminant analysis of anatomical data efficiently differentiated the five species. To evaluate chemical differences among the five species, we quantified (-)-catechin, (-)-catechin-7-O-β-D-apiofuranoside, (-)-catechin-7-O-α-L-rhamnopyranoside, (-)-catechin-7-O-β-D-xylopyranoside, (-)-catechin-7-O-β-D-glucopyranoside, and (-)-catechin-5-O-β-D-apiofuranoside using high-performance liquid chromatography with a diode-array detector. (-)-Catechin-7-O-β-D-apiofuranoside content was the highest among all compounds in all species, and (-)-catechin-7-O-α-L-rhamnopyranoside content was characteristically the highest in Ulmus parvifolia among the five species. Overall, the Ulmus species tested was able to be clearly distinguished on the basis of anatomy and chemical composition, which may be used as scientific criteria for appropriate identification and standard establishment for commercialization of these species
The Effect of Daminozide, Dark/Light Schedule and Copper Sulphate in Tissue Culture of Triticum timopheevii
Authors: Miroshnichenko Dmitry , Klementyeva Anna , Dolgov Sergey
Published: December 2021

Triticum timopheevii Zhuk. is a tetraploid wheat that is utilized worldwide as a valuable breeding source for wheat improvement. Gene-based biotechnologies can contribute to this field; however, T. timopheevii exhibits recalcitrance and albinism in tissue cultures, making this species of little use for manipulation through genetic engineering and genome editing. This study tested various approaches to increasing in vitro somatic embryogenesis and plant regeneration, while reducing the portion of albinos in cultures derived from immature embryos (IEs) of T. timopheevii. They included (i) adjusting the balance between 2,4-D and daminozide in callus induction medium; (ii) cultivation using various darkness/illumination schedules; and (iii) inclusion of additional concentrations of copper ions in the tissue culture medium. We achieved a 2.5-fold increase in somatic embryogenesis (up to 80%) when 50 mg L−1 daminozide was included in the callus induction medium together with 3 mg L−1 2,4-D. It was found that the dark cultivation for 20–30 days was superior in terms of achieving maximum culture efficiency; moreover, switching to light in under 2 weeks from culture initiation significantly increased the number of albino plants, suppressed somatic embryogenesis, and decreased the regeneration of green plants. Media containing higher levels of copper ions did not have a positive effect on the regeneration of green plants; contrarily, the elevated concentrations caused albinism in plantlets. The results and relevant conclusions of the present study might be valuable for establishing an improved protocol for the regeneration of green plants in tissue cultures of T. timopheevii.
Biological Control of Charcoal Rot in Peanut Crop through Strains of Trichoderma spp., in Puebla, Mexico
Authors: Martínez-Salgado Saira Jazmín , Andrade-Hoyos Petra , Parraguirre Lezama Conrado , Rivera-Tapia Antonio , Luna-Cruz Alfonso , Romero-Arenas Omar
Published: December 2021

Charcoal rot is an emerging disease for peanut crops caused by the fungus Macrophomina phaseolina. In Mexico, peanut crop represents an important productive activity for various rural areas; however, charcoal rot affects producers economically. The objectives of this research were: (a) to identify and morphologically characterize the strain “PUE 4.0” associated with charcoal rot of peanut crops from Buenavista de Benito Juárez, belonging to the municipality of Chietla in Puebla, Mexico; (b) determine the in vitro and in vivo antagonist activity of five Trichoderma species on M. phaseolina, and (c) determine the effect of the incidence of the disease on peanut production in the field. Vegetable tissue samples were collected from peanut crops in Puebla, Mexico with the presence of symptoms of charcoal rot at the stem and root level. The “PUE 4.0” strain presented 100% identity with M. phaseolina, the cause of charcoal rot in peanut crops from Buenavista de Benito Juárez. T. koningiopsis (T-K11) showed the highest development rate, the best growth speed, and the highest percentage of radial growth inhibition (PIRG) over M. phaseolina (71.11%) under in vitro conditions, in addition, T. koningiopsis (T-K11) showed higher production (1.60 ± 0.01 t/ha−1) and lower incidence of charcoal rot under field conditions. The lowest production with the highest incidence of the disease occurred in plants inoculated only with M. phaseolina (0.67 ± 0.01 t/ha−1) where elongated reddish-brown lesions were observed that covered 40% of the total surface of the main root.
Wound Healing Activities and Potential of Selected African Medicinal Plants and Their Synthesized Biogenic Nanoparticles
Authors: Tyavambiza Caroline , Dube Phumuzile , Goboza Mediline , Meyer Samantha , Madiehe Abram Madimabe , Meyer Mervin
Published: December 2021

In Africa, medicinal plants have been traditionally used as a source of medicine for centuries. To date, African medicinal plants continue to play a significant role in the treatment of wounds. Chronic wounds are associated with severe healthcare and socio-economic burdens despite the use of conventional therapies. Emergence of novel wound healing strategies using medicinal plants in conjunction with nanotechnology has the potential to develop efficacious wound healing therapeutics with enhanced wound repair mechanisms. This review identified African medicinal plants and biogenic nanoparticles used to promote wound healing through various mechanisms including improved wound contraction and epithelialization as well as antibacterial, antioxidant and anti-inflammatory activities. To achieve this, electronic databases such as PubMed, Scifinder® and Google Scholar were used to search for medicinal plants used by the African populace that were scientifically evaluated for their wound healing activities in both in vitro and in vivo models from 2004 to 2021. Additionally, data on the wound healing mechanisms of biogenic nanoparticles synthesized using African medicinal plants is included herein. The continued scientific evaluation of wound healing African medicinal plants and the development of novel nanomaterials using these plants is imperative in a bid to alleviate the detrimental effects of chronic wounds.
Lemnaceae and Orontiaceae Are Phylogenetically and Morphologically Distinct from Araceae
Authors: Tippery Nicholas P. , Les Donald H. , Appenroth Klaus J. , Sree K. Sowjanya , Crawford Daniel J. , Bog Manuela
Published: December 2021

Duckweeds comprise a distinctive clade of pleustophytic monocots that traditionally has been classified as the family Lemnaceae. However, molecular evidence has called into question their phylogenetic independence, with some authors asserting instead that duckweeds should be reclassified as subfamily Lemnoideae of an expanded family Araceae. Although a close phylogenetic relationship of duckweeds with traditional Araceae has been supported by multiple studies, the taxonomic disposition of duckweeds must be evaluated more critically to promote nomenclatural stability and utility. Subsuming duckweeds as a morphologically incongruent lineage of Araceae effectively eliminates the family category of Lemnaceae that has been widely used for many years. Instead, we suggest that Araceae subfamily Orontioideae should be restored to family status as Orontiaceae, which thereby would enable the recognition of three morphologically and phylogenetically distinct lineages: Araceae, Lemnaceae, and Orontiaceae.
Environmental Impact Assessment of Remediation Strategy in an Oil Spill in the Ecuadorian Amazon Region
Authors: García-Villacís Karina , Ramos-Guerrero Luis , Canga José Luis , Hidalgo-Lasso Daniel , Vargas-Jentzsch Paul
Published: December 2021

Past petroleum-extraction activities in Ecuador have contaminated its Amazon region. To assess the environmental impact attributed to remediation activities regarding the cleanup of these oil spills, two scenarios were studied according to Life Cycle Analysis methodology: (1) No-action, which means to leave the contamination in place without any further action and (2) Environmental remediation, where the environmental-load attributed to the remediation of the representative oil spill was studied. Results indicated that the no-action scenario presented a higher environmental impact for 12 out of the 16 environmental categories evaluated (climate change, ozone depletion, human toxicity non-cancer effects, particulate matter, ionizing radiation human health, ionizing radiation ecosystem, photochemical ozone formation, acidification, terrestrial eutrophication, marine eutrophication, freshwater ecotoxicity, mineral, fossil and renewable resource depletion). Moreover, the no-action scenario presented a global weighted score of contamination of 5.45 points, while the remediation scenario got a score of 3.3 points, which means that the remediation decreased by 39% of the global environmental impact due to the remediation activity applied, showing the positive influence of environmental remediation to mitigate the effects attributed to the presence of pollution sources associated to the petroleum industry in the Ecuadorian Amazon region.
Dynamic Mechanical Analysis of Thermally Aged Fique Fabric-Reinforced Epoxy Composites
Authors: Oliveira Michelle , da Luz Fernanda , da Costa Garcia Filho Fabio , Pereira Artur , de Oliveira Aguiar Vinícius , Lopera Henry , Monteiro Sergio
Published: December 2021

Dynamic mechanical analysis (DMA) is one of the most common methods employed to study a material’s viscoelastic properties. The effect of thermal aging on plain epoxy and a fique fabric-reinforced epoxy composite was investigated by comparing the mass loss, morphologies, and DMA properties of aged and unaged samples. In fact, thermal aging presents a big challenge for the high-temperature applications of natural fiber composites. In this work, both plain epoxy and fique fabric-reinforced epoxy composite were found to have different molecular mobility. This leads to distinct transition regions, with different changes in intensity caused by external loadings from time-aging. Three exponentially modified Gauss distribution functions (EMGs) were applied to loss factor curves of fique fabric-reinforced epoxy composite and plain epoxy, which allowed identifying three possible mobility ranges. From these results it was proposed that the thermal degradation behavior of natural fibers, especially fique fiber and their composites, might be assessed, based on their structural characteristics and mechanical properties.
A Wet-Spinning Process for Producing Carbon Nanotube/Polyvinylidene Fluoride Fibers Having Highly Consistent Electrical and Mechanical Properties
Authors: Kang Ki-Weon , Choi Chan-Woong , Jin Ji-Won
Published: December 2021

Studies of polymer/carbon nanotube (CNT) fibers typically focus on optimizing the overall properties, and the effects of structural variation on these properties are ignored. Thus, we investigated the longitudinal variation in the properties of CNT/polyvinylidene fluoride (CNT/PVDF) fibers prepared by wet spinning a solution of multi-walled nanotubes, PVDF, and dimethylacetamide. To this end, materials for the CNT/PVDF fiber were selected, and a dope solution was prepared using MWNT, PVDF, and dimethylacetamide (DMAc). To consider the process parameters that would affect the performance of the CNT/PVDF fiber during the wet-spinning process using the dope solution, the initial conditions for wet spinning were selected, including bath concentration, bath temperature, drying temperature, and elongation, and the CNT/PVDF fiber was spun under the corresponding conditions. Additionally, three performance stabilization processes were proposed to improve the initial conditions for wet spinning and manufacturing the fiber. Lastly, to confirm the reliability of the CNT/PVDF fiber in all sections, tensile strength, electrical conductivity, and cross-sectional images were analyzed for the 30 m, 60 m, and 90 m sections of the fiber, and the reliability of the wet-spinning process was verified.
Conversion of Whey Protein Aerogel Particles into Oleogels: Effect of Oil Type on Structural Features
Authors: Plazzotta Stella , Jung Isabella , Schroeter Baldur , Subrahmanyam Raman P. , Smirnova Irina , Calligaris Sonia , Gurikov Pavel , Manzocco Lara
Published: December 2021

Protein aerogel particles prepared by supercritical-CO2-drying (SCD) of ground whey protein (WP) hydrogels (20% w/w, pH 5.7) were converted into oleogels by dispersion in selected edible oils (castor, cod liver, corn, flaxseed, MCT, peanut and sunflower oil). The obtained oleogels were analysed for oil content, microstructure, rheological properties, and ATR-FTIR spectra. Except for castor oil, solid-like, plastic materials with comparable composition (80% oil, 20% WP) and rheological properties (G′~3.5 × 105 Pa, G″~0.20 × 105 Pa, critical stress~800 Pa, tanδ~0.060) were obtained. Optical and confocal microscopy showed that the generated structure was associated with the capillary-driven absorption of oil into the porous aerogel particles interconnected via particle-particle interactions. In this structure, the oil was stably entrapped. Results evidenced the reduced role of edible oil characteristics with the exception of castor oil, whose high polarity probably favoured particle–oil interactions hindering particle networking. This work demonstrates that WP aerogels could be regarded as versatile oleogel templates allowing the structuring of many edible oils into solid-like materials.
Highly Efficient Synthesis of Type B Gelatin and Low Molecular Weight Chitosan Nanoparticles: Potential Applications as Bioactive Molecule Carriers and Cell-Penetrating Agents
Authors: Gonzalez-Melo Cristina , Garcia-Brand Andres J. , Quezada Valentina , Reyes Luis H. , Muñoz-Camargo Carolina , Cruz Juan C.
Published: December 2021

Gelatin and chitosan nanoparticles have been widely used in pharmaceutical, biomedical, and nanofood applications due to their high biocompatibility and biodegradability. This study proposed a highly efficient synthesis method for type B gelatin and low-molecular-weight (LMW) chitosan nanoparticles. Gelatin nanoparticles (GNPs) were synthesized by the double desolvation method and the chitosan nanoparticles (CNPs) by the ionic gelation method. The sizes of the obtained CNPs and GNPs (373 ± 71 nm and 244 ± 67 nm, respectively) and zeta potential (+36.60 ± 3.25 mV and −13.42 ± 1.16 mV, respectively) were determined via dynamic light scattering. Morphology and size were verified utilizing SEM and TEM images. Finally, their biocompatibility was tested to assure their potential applicability as bioactive molecule carriers and cell-penetrating agents.
Synthesis and Characterization of Nonwoven Cotton-Reinforced Cellulose Hydrogel for Wound Dressings
Authors: Ahmad Faheem , Mushtaq Bushra , Butt Faaz Ahmed , Zafar Muhammad Sohail , Ahmad Sheraz , Afzal Ali , Nawab Yasir , Rasheed Abher , Ulker Zeynep
Published: December 2021

Hydrogels wound dressings have enormous advantages due to their ability to absorb high wound exudate, capacity to load drugs, and provide quick pain relief. The use of hydrogels as wound dressings in their original form is a considerable challenge, as these are difficult to apply on wounds without support. Therefore, the incorporation of polymeric hydrogels with a certain substrate is an emerging field of interest. The present study fabricated cellulose hydrogel using the sol–gel technique and reinforced it with nonwoven cotton for sustainable wound dressing application. The nonwoven cotton was immersed inside the prepared solution of cellulose and heated at 50 °C for 2 h to form cellulose hydrogel–nonwoven cotton composites and characterized for a range of properties. In addition, the prepared hydrogel composite was also loaded with titania particles to attain antibacterial properties. The Fourier transform infrared spectroscopy and scanning electron microscopy confirmed the formation of cellulose hydrogel layers inside the nonwoven cotton structure. The fabricated composite hydrogels showed good moisture management and air permeability, which are essential for comfortable wound healing. The wound exudate testing revealed that the fluid absorptive capacity of cellulose hydrogel nonwoven cotton composite was improved significantly in comparison to pure nonwoven cotton. The results reveal the successful hydrogel formation, having excellent absorbing, antimicrobial, and sustainable properties.
Lime/Sodium Carbonate Treated Seawater to Improve Flocculation and Sedimentation of Clay-Based Tailings
Authors: Pulgar Francisco , Ayala Luis , Jeldres Matías , Robles Pedro , Toledo Pedro G. , Salazar Iván , Jeldres Ricardo I.
Published: December 2021

Seawater treated with lime and sodium carbonate in different proportions to reduce magnesium and calcium contents is used in flocculation and sedimentation tests of artificial quartz and kaolin tailings. Solid complexes were separated from water by vacuum filtration, and factors such as lime/sodium carbonate ratio, kaolin content, flocculation time, and flocculant dose are evaluated. The growth of the aggregates was captured in situ by a focused beam reflectance measurement (FBRM) probe. Solid magnesium and calcium complexes are formed in raw seawater at pH 11, impairing the performance of flocculant polymers based on polyacrylamides. The results show that the settling rate improved when the treatment’s lime/sodium carbonate ratio increased. That is, when a greater removal of magnesium is prioritized over calcium. The amount of magnesium required to be removed depends on the mineralogy of the system: more clay will require more significant removal of magnesium. These results respond to the structural changes of the flocs, achieving that the more magnesium is removed, the greater the size and density of the aggregates. In contrast, calcium removal does not significantly influence flocculant performance. The study suggests the necessary conditions for each type of tailing to maximize water recovery, contributing to the effective closure of the water cycle in processes that use seawater with magnesium control.
Chitosan Functionalization: Covalent and Non-Covalent Interactions and Their Characterization
Authors: Nicolle Laura , Journot Céline M. A. , Gerber-Lemaire Sandrine
Published: December 2021

Chitosan (CS) is a natural biopolymer that has gained great interest in many research fields due to its promising biocompatibility, biodegradability, and favorable mechanical properties. The versatility of this low-cost polymer allows for a variety of chemical modifications via covalent conjugation and non-covalent interactions, which are designed to further improve the properties of interest. This review aims at presenting the broad range of functionalization strategies reported over the last five years to reflect the state-of-the art of CS derivatization. We start by describing covalent modifications performed on the CS backbone, followed by non-covalent CS modifications involving small molecules, proteins, and metal adjuvants. An overview of CS-based systems involving both covalent and electrostatic modification patterns is then presented. Finally, a special focus will be given on the characterization techniques commonly used to qualify the composition and physical properties of CS derivatives.
Microplastic Contamination in Soils: A Review from Geotechnical Engineering View
Authors: Monkul Mehmet Murat , Özhan Hakkı O.
Published: December 2021

Microplastic contamination is a growing threat to marine and freshwater ecosystems, agricultural production, groundwater, plant growth and even human and animal health. Disintegration of plastic products due to mainly biochemical or physical activities leads to the formation and existence of microplastics in significant amounts, not only in marine and freshwater environments but also in soils. There are several valuable studies on microplastics in soils, which have typically focused on environmental, chemical, agricultural and health aspects. However, there is also a need for the geotechnical engineering perspective on microplastic contamination in soils. In this review paper, first, degradation, existence and persistence of microplastics in soils are assessed by considering various studies. Then, the potential role of solid waste disposal facilities as a source for microplastics is discussed by considering their geotechnical design and addressing the risk for the migration of microplastics from landfills to soils and other environments. Even though landfills are considered as one of the main geotechnical structures that contribute to the formation of considerably high amounts of microplastics and their contamination in soils, some other geotechnical engineering applications (i.e., soil improvement with tirechips, forming engineering fills with dredged sediments, soil improvement with synthetic polymer-based fibers, polystyrene based lightweight fill applications), as potential local source for microplastics, are also mentioned. Finally, the importance of geotechnical engineering as a mitigation tool for microplastics is emphasized and several important research topics involving geotechnical engineering are suggested.
Cellulose Acetate Nanofibers: Incorporating Hydroxyapatite (HA), HA/Berberine or HA/Moghat Composites, as Scaffolds to Enhance In Vitro Osteoporotic Bone Regeneration
Authors: Shaban Nadia Z. , Kenawy Marwa Y. , Taha Nahla A. , Abd El-Latif Mona M. , Ghareeb Doaa A.
Published: December 2021

The specific objective of this study was to stabilize a simple valid method to prepare pure nanorod hydroxyapatite (HA) mixed with berberine chloride (BER) and Moghat water extract (ME) as composites for incorporation into cellulose acetate (CA) nanofibers to be used as novel bone scaffolds and to determine their efficacy in bone regeneration process In Vitro. Preparation of HA/BER and HA/ME composites were performed by mixing powders using the ball-milling machine. The HA, HA/BER, and HA/ME composites at a concentration of 6.25, 12.5, 25, 50, 100, and 200 mg were mixed with CA solution (13%), then the fiber was formed using electrospinning technique. The properties of the obtained CA fibers were investigated (SEM, TEM, EDX, FTIR, TGA, water uptake, porosity, and mechanical tests). The efficacy of HA and HA composites loaded into CA nanofiber on osteoblast and osteoclast differentiation were measured by tacking ALP, osteocalcin, TRAcP, calcium, and total protein concentration. Moreover, their effects on cell differentiation (CD90 and PARP- ɣ) and death markers (GSK3b, MAPK, Wnt-5 and β-catenin) were evaluated by using ELISA and qPCR. The obtained TEM results indicated that the continuous CA and CA/HA composites electrospun fibers have ultrafine fiber diameters of about 200 nm and uniform distribution of discrete n-HA clusters throughout. In addition, hydrocortisone (HCT) was found to increase the formation of adipocytes and osteoclastic markers CD90 and p38-MAPK which indicated the bone lose process take placed. Treatment with CA loaded with HA, HA/BER or HA/ME decreased CD90, Wnt-5, PARP- ɣ, GSK3b and p38-MAPK associated elevation of osteogenic markers: ALP and osteocalcin. Moreover, HCT overexpressed RANKL and down expressed Osterix gene. Treatment with CA/HA/BER or CA/HA/ME downregulated RANKL and upregulated Osterix associated with a reduction in RANKL/OPG ratio, at p < 0.05. In conclusion, novel CA composite nanofibers (CA/HA/BER and CA/HA/ME) reversed the HCT adverse effect on osteoblast cell death through canonical and non-canonical pathways regulated by Wnt/β-catenin and Wnt/Ca(2+) pathways. Furthermore, our data confirmed that the novel scaffolds create a crosstalk between RUNX-2, RANKL, p38-MAPK, and Wnt signals which positively impact bone regeneration process. Treatment with CA/HA/BER is better compared to the treatment with CA/HA/ME. Nevertheless, both are considered as alternative biomaterial scaffolds with a potential for biomedical applications in the field of bone tissue engineering.
Performance of Fly Ash-Based Inorganic Polymer Mortar with Petroleum Sludge Ash
Authors: Kankia Mubarak Usman , Baloo Lavania , Danlami Nasiru , Mohammed Bashar S. , Haruna Sani , Abubakar Mahmud , Jagaba Ahmad Hussaini , Sayed Khalid , Abdulkadir Isyaka , Salihi Ibrahim Umar
Published: December 2021

Petroleum sludge is a waste product resulting from petroleum industries and it is a major source of environmental pollution. Therefore, developing strategies aimed at reducing its environmental impact and enhance cleaner production are crucial for environmental mortar. Response surface methodology (RSM) was used in designing the experimental work. The variables considered were the amount of petroleum sludge ash (PSA) in weight percent and the ratio of sodium silicate to sodium hydroxide, while the concentration of sodium hydroxide was kept constant in the production of geopolymer mortar cured at a temperature of 60 °C for 20 h. The effects of PSA on density, compressive strength, flexural strength, water absorption, drying shrinkage, morphology, and pore size distribution were investigated. The addition of PSA in the mortar enhanced the mechanical properties significantly at an early age and 28 days of curing. Thus, PSA could be used as a precursor material in the production of geopolymer mortar for green construction sustainability. This study aimed to investigate the influence of PSA in geopolymer mortar.
Self-Healing of a Covalently Cross-Linked Polymer Electrolyte Membrane by Diels-Alder Cycloaddition and Electrolyte Embedding for Lithium Ion Batteries
Authors: Chen Lijuan , Cai Xisen , Sun Zhonghui , Zhang Baohua , Bao Yu , Liu Zhenbang , Han Dongxue , Niu Li
Published: December 2021

Thermally reversible self-healing polymer (SHP) electrolyte membranes are obtained by Diels-Alder cycloaddition and electrolyte embedding. The SHP electrolytes membranes are found to display high ionic conductivity, suitable flexibility, remarkable mechanical properties and self-healing ability. The decomposition potential of the SHP electrolyte membrane is about 4.8 V (vs. Li/Li+) and it possesses excellent electrochemical stability, better than that of the commercial PE film which is only stable up to 4.5 V (vs. Li/Li+). TGA results show that the SHP electrolyte membrane is thermally stable up to 280 °C in a nitrogen atmosphere. When the SHP electrolyte membrane is used as a separator in a lithium-ion battery with an LCO-based cathode, the SHP membrane achieved excellent rate capability and stable cycling for over 100 cycles, and the specific discharge capacity could be almost fully recovered after self-healing. Furthermore, the electrolyte membrane exhibits excellent electrochemical performance, suggesting its potential for application in lithium-ion batteries as separator material.
A Simple Approach to Control the Physical and Chemical Features of Custom-Synthesized N-Doped Carbon Nanotubes and the Extent of Their Network Formation in Polymers: The Importance of Catalyst to Substrate Ratio
Authors: Erfanian Elnaz , Kamkar Milad , Pawar Shital Patangrao , Keteklahijani Yalda Zamani , Arjmand Mohammad , Sundararaj Uttandaraman
Published: December 2021

This study intends to reveal the significance of the catalyst to substrate ratio (C/S) on the structural and electrical features of the carbon nanotubes and their polymeric nanocomposites. Here, nitrogen-doped carbon nanotube (N-MWNT) was synthesized via a chemical vapor deposition (CVD) method using three ratios (by weight) of iron (Fe) catalyst to aluminum oxide (Al2O3) substrate, i.e.,1/9, 1/4, and 2/3, by changing the Fe concentration, i.e., 10, 20, and 40 wt.% Fe. Therefore, the synthesized N-MWNT are labelled as (N-MWNTs)10, (N-MWNTs)20, and (N-MWNTs)40. TEM, XPS, Raman spectroscopy, and TGA characterizations revealed that C/S ratio has a significant impact on the physical and chemical properties of the nanotubes. For instance, by increasing the Fe catalyst from 10 to 40 wt.%, carbon purity increased from 60 to 90 wt.% and the length of the nanotubes increased from 1.2 to 2.6 µm. Interestingly, regarding nanotube morphology, at the highest C/S ratio, the N-MWNTs displayed an open-channel structure, while at the lowest catalyst concentration the nanotubes featured a bamboo-like structure. Afterwards, the network characteristics of the N-MWNTs in a polyvinylidene fluoride (PVDF) matrix were studied using imaging techniques, AC electrical conductivity, and linear and nonlinear rheological measurements. The nanocomposites were prepared via a melt-mixing method at various loadings of the synthesized N-MWNTs. The rheological results confirmed that (N-MWNTs)10, at 0.5–2.0 wt.%, did not form any substantial network through the PVDF matrix, thereby exhibiting an electrically insulative behavior, even at a higher concentration of 3.0 wt.%. Although the optical microscopy, TEM, and rheological results confirmed that both (N-MWNTs)20 and (N-MWNTs)40 established a continuous 3D network within the PVDF matrix, (N-MWNTs)40/PVDF nanocomposites exhibited approximately one order of magnitude higher electrical conductivity. The higher electrical conductivity of (N-MWNTs)40/PVDF nanocomposites is attributed to the intrinsic chemical features of (N-MWNTs)40, such as nitrogen content and nitrogen bonding types.
Optimization of Injection-Molding Process for Thin-Walled Polypropylene Part Using Artificial Neural Network and Taguchi Techniques
Authors: Moayyedian Mehdi , Dinc Ali , Mamedov Ali
Published: December 2021

Plastics are commonly used engineering materials, and the injection-molding process is well known as an efficient and economic manufacturing technique for producing plastic parts with various shapes and complex geometries. However, there are certain manufacturing defects related to the injection-molding process, such as short shot, shrinkage, and warpage. This research aims to find optimum process parameters for high-quality end products with minimum defect possibility. The Artificial Neural Network and Taguchi Techniques are used to find a set of optimal process parameters. The Analytic Hierarchy Process is used to calculate the weight of each defect in the proposed thin-walled part. The Finite Element Analysis (FEA) using SolidWorks plastics is used to simulate the injection-molding process for polypropylene parts and validate the proposed optimal set of process parameters. Results showed the best end-product quality was achieved at a filling time of 1 s, cooling time of 3 s, pressure-holding time of 3 s, and melt temperature of 230 °C. The end-product quality was mostly influenced by filling time, followed by the pressure-holding time. It was found that the margin of error for the proposed optimization methods was 1.5%, resulting from any uncontrollable parameters affecting the injection-molding process.
Suzuki–Miyaura Catalyst-Transfer Polycondensation of Triolborate-Type Carbazole Monomers
Authors: Kobayashi Saburo , Ashiya Mayoh , Yamamoto Takuya , Tajima Kenji , Yamamoto Yasunori , Isono Takuya , Satoh Toshifumi
Published: December 2021

Herein, we report the Suzuki–Miyaura catalyst-transfer polycondensation (SCTP) of triolborate-type carbazole monomers, i.e., potassium 3-(6-bromo-9-(2-octyldodecyl)-9H-carbazole-2-yl)triolborate (M1) and potassium 2-(7-bromo-9-(2-octyldodecyl)-9H-carbazole-2-yl) triolborate (M2), as an efficient and versatile approach for precisely synthesizing poly[9-(2-octyldodecyl)-3,6-carbazole] (3,6-PCz) and poly[9-(2-octyldodecyl)-2,7-carbazole] (2,7-PCz), respectively. The SCTP of triolborate-type carbazole monomers was performed in a mixture of THF/H2O using an initiating system consisted of 4-iodobenzyl alcohol, Pd2(dba)3•CHCl3, and t-Bu3P. In the SCTP of M1, cyclic by-product formation was confirmed, as reported for the corresponding pinacolboronate-type monomer. By optimizing the reaction temperature and reaction time, we successfully synthesized linear end-functionalized 3,6-PCz for the first time. The SCTP of M2 proceeded with almost no side reaction, yielding 2,7-PCz with a functional initiator residue at the α-chain end. Kinetic and block copolymerization experiments demonstrated that the SCTP of M2 proceeded in a chain-growth and controlled/living polymerization manner. This is a novel study on the synthesis of 2,7-PCz via SCTP. By taking advantage of the well-controlled nature of this polymerization system, we demonstrated the synthesis of high-molecular-weight 2,7-PCzs (Mn = 5–38 kg mol−1) with a relatively narrow ÐM (1.35–1.48). Furthermore, we successfully synthesized fluorene/carbazole copolymers as well as 2,7-PCz-containing diblock copolymers, demonstrating the versatility of the present polymerization system as a novel synthetic strategy for well-defined polycarbazole-based materials.
Accurate Description of Protein–Protein Recognition and Protein Aggregation with the Implicit-Solvent-Based PACSAB Protein Model
Authors: Emperador Agustí
Published: December 2021

We used the PACSAB protein model, based on the implicit solvation approach, to simulate protein–protein recognition and study the effect of helical structure on the association of aggregating peptides. After optimization, the PACSAB force field was able to reproduce correctly both the correct binding interface in ubiquitin dimerization and the conformational ensemble of the disordered protein activator for hormone and retinoid receptor (ACTR). The PACSAB model allowed us to predict the native binding of ACTR with its binding partner, reproducing the refolding upon binding mechanism of the disordered protein.
Preparation and Characterization of Intrinsic Low-κ Polyimide Films
Authors: Sun Yu , Li Tao , Dai Haiyang , Wang Manman , Xue Renzhong , Chen Jing , Liu Dewei
Published: December 2021

Three fluorinated polyimide (PI-FP, PI-FO and PI-FH) films with low dielectric constants and excellent comprehensive properties were successfully prepared using a polycondensation reaction method by incorporating p-phenylenediamine (PDA), 4-4′-diaminodiphenyl ether (ODA) and 4,4′-(Hexafluoroisopropylidene) bis (p-phenyleneoxy) dianiline (HFPBDA) into 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA), respectively. The effects of the diamine monomer structure on optical, dielectric and mechanical properties were investigated. Compared with PDA and ODA, HFPBDA can effectively improve the optical and dielectric properties of PI due to due to its special chain structure. Among the three PI films, PI-FH film presents the best optic transmission (highest transmittance = 90.2%) and highest energy gap (2.69 eV). The dielectric properties of PI-FH film improve the most. The dielectric constant and loss at 104 Hz are reduced to 2.05 and 0.0034 at 104 Hz, respectively, and remain stable up to 250 °C. The mechanical properties decrease in turn for PI-FP, PI-FO and PI-FH films due to the increase in free volume fraction. Nevertheless, PI-FH film still exhibits good mechanical properties with a tensile strength of 88.4 Mpa, a tensile modulus of 2.11 GPa and an elongation at break of 4.1%. The correlation between the dielectric and mechanical properties of PI films and their free volume characteristics is well explained with the help of positron annihilation spectroscopy.
Simulation of the Hybrid Carbon-Aramid Composite Materials Based on Mechanical Characterization by Digital Image Correlation Method
Authors: Cerbu Camelia , Ursache Stefania , Botis Marius Florin , Hadăr Anton
Published: December 2021

As hybrid carbon-aramid composites become widely used in various industries, it has become imperative to mechanically characterize them using accurate methods of measuring the entire deformation field such as the digital image correlation (DIC) method. The accuracy of the numerical simulation of carbon-aramid composite structures depends on the accuracy of the elastic constants. Therefore, the goal of this research is to model and simulate the mechanical behaviour of the composite based on epoxy resin reinforced with carbon-aramid woven fabric by considering the mechanical properties investigated by tensile test combined with DIC and the bending test. The curves of the transverse strains related to the longitudinal strains were investigated using DIC in order to determine the Poisson’s ratios in the case of tensile tests applied in warp or weft directions of the reinforcement fabric. The impact strength determined by Charpy tests is also reported. The other main objective is to use the analytical models to compute the tensile and flexural moduli of elasticity for the fictitious orthotropic materials which behave similarly to the carbon-aramid composite investigated. The simulations regarding the behaviour of the carbon-aramid composite in tensile and bending tests were validated by the experimental results, since the maximum errors recorded between experimental and theoretical results were 0.19% and 0.15% for the equivalent tensile modulus and for the equivalent flexural modulus, respectively.
A Novel Approach of Bioesters Synthesis through Different Technologies by Highlighting the Lowest Energetic Consumption One
Authors: Popa Simona , Tamas Andra , Simulescu Vasile , Jurcau Dorin , Boran Sorina , Mosoarca Giannin
Published: December 2021

Fatty acids esters have a wide application as bioplasticizers and biolubricants in different industries, obtained mainly in classic batch reactors, through an equilibrium complex reaction, that involves high temperatures, long reaction times, vigorously stirring, and much energy consumption. To overcome these shortcomings, we synthesized a series of fatty acid esters (soybean oil fatty acids being the acid components with various hydroxyl compounds) through novel low energy consumption technologies using a bubble column reactor, a microwave field reactor and for comparison meaning, a classic batch reactor. The obtained bioesters physicochemical properties were similar to one another, a good concordance among their rheological properties was obtained, but the energetic consumption is lower when using the bubble column or the microwave reactors instead of the classical batch reactor.
Biodegradable Poly(Butylene Adipate-Co-Terephthalate) and Thermoplastic Starch-Blended TiO2 Nanocomposite Blown Films as Functional Active Packaging of Fresh Fruit
Authors: Phothisarattana Danaya , Wongphan Phanwipa , Promhuad Khwanchat , Promsorn Juthathip , Harnkarnsujarit Nathdanai
Published: December 2021

Biodegradable polymers can be used for eco-friendly, functional, active packaging to preserve food quality. Incorporation of titanium dioxide (TiO2) nanoparticles into polymer packaging enhances ethylene-scavenging activity and extends the shelf-life of fresh produce. In this study, TiO2 nanoparticles were incorporated into biodegradable poly(butylene adipate-co-terephthalate) (PBAT)- and thermoplastic cassava starch (TPS)-blended films to produce nanocomposite packaging via blown-film extrusion. The effects of TiO2 on morphology, packaging properties, and applications as functional packaging for fresh produce were investigated. Increased TiO2 in the film packaging increased amorphous starch content and hydrogen bonding by interacting with the TPS phase of the polymer blend, with negligible chemical interaction with the PBAT component and identical mechanical relaxation in the PBAT phase. Surface topography indicated void space due to non-homogeneous dispersion causing increased oxygen and carbon dioxide permeability. Homogeneous dispersion of fine TiO2 nanoparticles increased mechanical strength and reduced oxygen, carbon dioxide, and water vapor permeability. Films containing TiO2 also showed efficient oxygen-scavenging activity that removed residual oxygen from the package headspace dependent on the levels and morphology of nanoparticles in the film matrices. Banana fruit packaged in films containing TiO2 recorded slower darkening color change and enhanced shelf-life with increasing TiO2 content.
Modification of Xanthan Gum for a High-Temperature and High-Salinity Reservoir
Authors: Said Mohamed , Haq Bashirul , Al Shehri Dhafer , Rahman Mohammad Mizanur , Muhammed Nasiru Salahu , Mahmoud Mohamed
Published: December 2021

Tertiary oil recovery, commonly known as enhanced oil recovery (EOR), is performed when secondary recovery is no longer economically viable. Polymer flooding is one of the EOR methods that improves the viscosity of injected water and boosts oil recovery. Xanthan gum is a relatively cheap biopolymer and is suitable for oil recovery at limited temperatures and salinities. This work aims to modify xanthan gum to improve its viscosity for high-temperature and high-salinity reservoirs. The xanthan gum was reacted with acrylic acid in the presence of a catalyst in order to form xanthan acrylate. The chemical structure of the xanthan acrylate was verified by FT-IR and NMR analysis. The discovery hybrid rheometer (DHR) confirmed that the viscosity of the modified xanthan gum was improved at elevated temperatures, which was reflected in the core flood experiment. Two core flooding experiments were conducted using six-inch sandstone core plugs and Arabian light crude oil. The first formulation—the xanthan gum with 3% NaCl solution—recovered 14% of the residual oil from the core. In contrast, the modified xanthan gum with 3% NaCl solution recovered about 19% of the residual oil, which was 5% higher than the original xanthan gum. The xanthan gum acrylate is therefore more effective at boosting tertiary oil recovery in the sandstone core.
PBPK Modeling and Simulation and Therapeutic Drug Monitoring: Possible Ways for Antibiotic Dose Adjustment
Authors: Ferreira Abigail , Lapa Rui , Vale Nuno
Published: December 2021

Pharmacokinetics (PK) is a branch of pharmacology present and of vital importance for the research and development (R&D) of new drugs, post-market monitoring, and continued optimizations in clinical contexts. Ultimately, pharmacokinetics can contribute to improving patients’ clinical outcomes, helping enhance the efficacy of treatments, and reducing possible adverse side effects while also contributing to precision medicine. This article discusses the methods used to predict and study human pharmacokinetics and their evolution to the current physiologically based pharmacokinetic (PBPK) modeling and simulation methods. The importance of therapeutic drug monitoring (TDM) and PBPK as valuable tools for Model-Informed Precision Dosing (MIPD) are highlighted, with particular emphasis on antibiotic therapy since dosage adjustment of antibiotics can be vital to ensure successful clinical outcomes and to prevent the spread of resistant bacterial strains.
Splitting Physical Exergy by Its Feasible Working Ways
Authors: Gao Dongbo , Peng Xiaoqi , Song Yanpo , Zhou Ping
Published: December 2021

This paper analyzed the problems associated with physical exergy splitting, and based on this, presented a new splitting method. This new method splits the physical exergy into three parts according to the feasible working ways, i.e.,: the direct, indirect, and adaptive exergy. The computational method and the physical meaning of the three exergy parts were presented in detail in terms of graphic representation and mathematical derivation. Then, it was applied to the exergy analysis of a thermal power cycle. The results show that compared with the conventional method which splits the physical exergy into thermal and mechanical parts, the current exergy splitting method can better represent the change rule of the working ability of the real working stream in the cycle and the influence of some operation parameters, such as the turbine inlet temperature, on the real working ability. The study suggests that the new method can make the exergy analysis more helpful and guidable in its applications.