bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Composition and Phytotoxic, Antibacterial and Antibiofilm Activity of the Essential Oils of Eucalyptus occidentalis, E. striaticalyx and E. stricklandii
Authors: Khammassi Marwa , Polito Flavio , Amri Ismail , Khedhri Sana , Hamrouni Lamia , Nazzaro Filomena , Fratianni Florinda , De Feo Vincenzo
Published: September 2022

The Eucalyptus genus (Myrtaceae) is characterized by a richness in essential oils (EO) with multiple biological activities. This study reports the chemical composition and the phytotoxic and antimicrobial activities of the EOs from Tunisian E.occidentalis, E.striaticalyx and E.stricklandii. The EOs were analyzed using GC/MS and their phytotoxicities were assessed against the germination and seedling growth of Sinapis arvensis, Trifolium campestre and Lolium rigidum. Antimicrobial activity was investigated against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. All EOs were rich in oxygenated monoterpenes (36.3–84.8%); the EO of E.occidentalis was rich in sesquiterpenes, both oxygenated and hydrocarbon (40.0% and 15.0%, respectively). Eucalyptol was the main constituent in all samples. The EOs showed phytotoxic activity on seed germination and seedling growth, depending both on chemical composition and weed. The EOs show a remarkable antibacterial potential resulting in a significant inhibition of the formation of bacterial biofilm and its metabolism, depending on the EO and the strain, with activity on the mature biofilm as well. Therefore, these Eucalyptus EOs could have potential applications both in the food and health fields.
A DFT Study on the Excited Electronic States of Cyanopolyynes: Benchmarks and Applications
Authors: Gronowski Marcin , Kołos Robert
Published: September 2022

Highly unsaturated chain molecules are interesting due to their potential application as nanowires and occurrence in interstellar space. Here, we focus on predicting the electronic spectra of polyynic nitriles HC2m+1N (m = 0–13) and dinitriles NC2n+2N (n = 0–14). The results of time-dependent density functional theory (TD-DFT) calculations are compared with the available gas-phase and noble gas matrix experimental data. We assessed the performance of fifteen functionals and five basis sets for reproducing (i) vibrationless electronic excitation energies and (ii) vibrational frequencies in the singlet excited states. We found that the basis sets of at least triple-ζ quality were necessary to describe the long molecules with alternate single and triple bonds. Vibrational frequency scaling factors are similar for the ground and excited states. The benchmarked spectroscopic parameters were shown to be acceptably reproduced with adequately chosen functionals, in particular ωB97X, CAM-B3LYP, B3LYP, B971, and B972. Select functionals were applied to study the electronic excitation of molecules up to HC27N and C30N2. It is demonstrated that optical excitation leads to a shift from the polyyne- to a cumulene-like electronic structure.
Observation and Analysis of Staircase Response of Single Palladium Nanoparticle Collision on Gold Ultramicroelectrodes
Authors: Rudakemwa Hubert , Kim Ki Jun , Park Tae Eun , Son Hyeryeon , Na Jaedo , Kwon Seong Jung
Published: September 2022

Collision (or impact) of single palladium nanoparticles (Pd NPs) on gold (Au), copper (Cu), nickel (Ni), and platinum (Pt) ultramicroelectrodes (UMEs) were investigated via electrocatalytic amplification method. Unlike the blip responses of previous Pd NP collision studies, the staircase current response was obtained with the Au UME. The current response, including collision frequency and peak magnitude, was analyzed depending on the material of the UME and the applied potential. Adsorption factors implying the interaction between the Pd NP and the UMEs are suggested based on the experimental results.
Effect of Whey Protein Purity on the Characteristics of Algae Oil-Loaded Encapsulates Obtained by Electrospraying Assisted by Pressurized Gas
Authors: Prieto Cristina , Talón Emma , Noreña Caciano Zapata , Lagaron Jose M.
Published: September 2022

In this paper, the effect of protein purity in three different whey protein grades on the characteristics of algae oil encapsulates obtained via room-temperature electrospraying assisted by pressurized gas (EAPG) encapsulation process was studied. Three different commercial grades of whey protein purity were evaluated, namely 35, 80, and 90 wt.%. Oil nanodroplets with an average size of 600 nm were homogeneously entrapped into whey protein microparticles 3 µm in size. However, the sphericity and the surface smoothness of the microparticles increased by increasing the protein purity in the grades of whey protein studied. The porosity of the microparticles was also dependent on protein purity as determined by nitrogen adsorption–desorption isotherms, being smaller for larger contents of protein. Interestingly, the lowest extractable oil was obtained with WP35, probably due to the high content of lactose. The peroxide values confirmed the superior protective effect of the protein, obtaining the smallest peroxide value for WP90, a result that is consistent with its reduced porosity and with its lower permeability to oxygen, as confirmed by the fluorescence decay–oxygen consumption method. The accelerated stability assay against oxidation confirmed the higher protection of the WP80 and WP90. In addition, the increased content in protein implied a higher thermal stability according to the thermogravimetric analysis. These results further confirm the importance of the adequate selection of the composition of wall materials together with the encapsulation method.
Dynamics of Rotating Micropolar Fluid over a Stretch Surface: The Case of Linear and Quadratic Convection Significance in Thermal Management
Authors: Ali Bagh , Ahammad N. Ameer , Awan Aziz Ullah , Guedri Kamel , Tag-ElDin ElSayed M. , Majeed Sonia
Published: September 2022

This article analyzes the significance of linear and quadratic convection on the dynamics of micropolar fluid due to a stretching surface in the presence of magnetic force and a rotational frame. Modern technological implementations have attracted researchers to inquire about non-Newtonian fluids, so the effect of linear and nonlinear convection conditions is accounted for in the dynamics of non-Newtonian fluid. The highly nonlinear governing equations are converted into a system of dimensionless ODEs by using suitable similarity transformations. The bvp4c technique is applied in MATLAB software to obtain a numerical solution. This investigation examines the behavior of various parameters with and without quadratic convection on the micro-rotation, velocity, and temperature profiles via graphical consequences. The velocity profile decreases with a higher input by magnetic and rotating parameters, and fluid velocity is more elevated in the nonlinear convection case. However, the temperature profile shows increasing behavior for these parameters and quadratic convection increases the velocity profile but has an opposite tendency for the temperature distribution. The micro-rotation distribution is augmented for higher magnetic inputs in linear convection but reduces against thermal buoyancy.
CuCo2S4 Nanoparticles Embedded in Carbon Nanotube Networks as Sulfur Hosts for High Performance Lithium-Sulfur Batteries
Authors: Wang Hongying , Song Yanli , Zhao Yanming , Zhao Yan , Wang Zhifeng
Published: September 2022

Rational design of sulfur hosts for lithium-sulfur (Li-S) batteries is essential to address the shuttle effect and accelerate reaction kinetics. Herein, the composites of bimetallic sulfide CuCo2S4 loaded on carbon nanotubes (CNTs) are prepared by hydrothermal method. By regulating the loading of CuCo2S4 nanoparticles, it is found that when Cu2+ and CNT are prepared in a 10:1 ratio, the CuCo2S4 nanoparticles loaded on the CNT are relatively uniformly distributed, avoiding the occurrence of agglomeration, which improves the electrical conductivity and number of active sites. Through a series of electrochemical performance tests, the S/CuCo2S4-1/CNT presents a discharge specific capacity of 1021 mAh g−1 at 0.2 C after 100 cycles, showing good cycling stability. Even at 1 C, the S/CuCo2S4-1/CNT cathode delivers a discharge capacity of 627 mAh g−1 after 500 cycles. This study offers a promising strategy for the design of bimetallic sulfide-based sulfur hosts in Li-S batteries.
Supramolecular Precursor Strategy to Construct g-C3N4/Silica Hybrid Nanosheets for Photocatalytic Degradation of Dye and Antibiotic Pollutants
Authors: Yu Yongsheng , Wang Jinghan , Yan Zhaoli , Jing Qiangshan , Liu Peng , Xu Bing
Published: September 2022

To construct a highly active g-C3N4 (CN)/silica hybrid nanosystem, the supramolecular precursor strategy of introducing melamine–cyanuric acid (MCA) by synergistically using micromolecular melamine (m) and urea (u) for CN nanostructure construction on the silica nanosheets (SiNSs) surface was researched. The results showed that the introduction of MCA supramolecular aggregates promoted the generation of ordered CN nanostructures attached to SiNSs, and the morphology of the CN nanostructure could be regulated through the m/u mass ratio. When the ratio is equal to 1/30, a typical g-C3N4/silica hybrid nanosheet (mu-CN/SiNSs-3) was successfully prepared, which showed the ultra-high photocatalytic activity for Rhodamine B dye degradation within 25 min with an apparent rate constant of 0.186 min−1, owing to the large surface area of highly dispersed and ordered CN nanosheets, a strong interaction between CN and SiNSs, high photogenerated carriers separation efficiency, and the more negative conduction band potential offering more active species of 1O2 and •O2−. Unexpectedly, the mu-CN/SiNSs-2 composite (m/u = 1/10) exhibited the highest activity for tetracycline antibiotic degradation, mainly due to the morphological advantage of a certain number of nanotubes generated on the CN/SiNSs hybrid nanosheets. It indicates that the supramolecular precursor strategy by synergistically using melamine and urea is highly efficient for the nanostructure construction of the CN/SiNSs hybrid system, enabling an appropriate nanostructure for the photodegradation of various pollutants.
Colistin Resistance Mechanism in Enterobacter hormaechei subsp. steigerwaltii Isolated from Wild Boar (Sus scrofa) in France
Authors: Laidoudi Younes , Ngaiganam Edgarthe Priscilla , Marié Jean-Lou , Pagnier Isabelle , Rolain Jean-Marc , Mouhamadou Diene Seydina , Davoust Bernard
Published: September 2022

Wild animals may act as efficient antimicrobial-resistance reservoirs and epidemiological links between humans, livestock, and natural environments. By using phenotypic and genotypic characterization, the present study highlighted the occurrence of an antimicrobial-resistant (i.e., amoxicillin, amoxicillin–clavulanic acid, cephalothin, and colistin) Enterobacter hormaechei subsp. steigerwaltii strain in wild boar (Sus scrofa) from France. The molecular analysis conducted showed non-synonymous mutations in the pmrA/pmrB and phoQ/phoP operons and the phoP/Q regulator mgrB gene, leading to colistin resistance. The present data highlight the need for continuous monitoring of multidrug-resistant bacteria in wild animals to limit the spread of these threatening pathogens.
Diverse Genotypes of Cryptosporidium in Sheep in California, USA
Authors: Li Xunde , Vodovoza Tamara , Atwill Edward R.
Published: September 2022

Cryptosporidium spp. is a parasite that can infect a wide variety of vertebrate species. The parasite has been detected in sheep worldwide with diverse species and genotypes of various levels of zoonotic potential and public health concern. The purpose of this study was to determine the distribution of genotypes of Cryptosporidium in sheep in California, USA. Microscopic positive samples from individual sheep from central and northern California ranches were genotyped by sequencing a fragment of the 18S rRNA gene and BLAST analysis. Eighty-eight (63.8%) of the microscopic positive samples were genotyped, and multiple genotypes of Cryptosporidium were identified from sheep in the enrolled ranches. Approximately 89% of isolates (n = 78) were C. xiaoi or C. bovis, 10% of isolates (n = 9) were C. ubiquitum, and 1% of isolates (n = 1) were C. parvum. The C. parvum and C. ubiquitum isolates were detected only from lambs and limited to four farms. Given that the majority of Cryptosporidium species (i.e., C. xiaoi and C. bovis) were of minor zoonotic concern, the results of this study suggest that sheep are not a reservoir of major zoonotic Cryptosporidium in California ranches.
Differences in Density Dependence among Tree Mycorrhizal Types Affect Tree Species Diversity and Relative Growth Rates
Authors: Wei Boliang , Zhong Lei , Liu Jinliang , Zheng Fangdong , Jin Yi , Xie Yuchu , Lei Zupei , Shen Guochun , Yu Mingjian
Published: September 2022

Conspecific negative density dependence (CNDD) may vary by tree mycorrhizal type. However, whether arbuscular mycorrhizal (AM)-associated tree species suffer from stronger CNDD than ectomycorrhizal (EcM) and ericoid mycorrhizal (ErM)-associated tree species at different tree life stages, and whether EcM tree species can promote AM and ErM saplings and adults growth, remain to be studied. Based on the subtropical evergreen broad-leaved forest data in eastern China, the generalized linear mixed-effects model was used to analyze the effects of the conspecific density and heterospecific density grouped by symbiont mycorrhizal type on different tree life stages of different tree mycorrhizal types. The results showed that compared to other tree mycorrhizal types at the same growth stage, EcM saplings and AM adults experienced stronger CNDD. Heterospecific EcM density had a stronger positive effect on AM and ErM individuals. Species diversity and average relative growth rate (RGR) first increased and then decreased with increasing basal area (BA) ratios of EcM to AM tree species. These results suggested that the stronger CNDD of EcM saplings and AM adults favored local species diversity over other tree mycorrhizal types. The EcM tree species better facilitated the growth of AM and ErM tree species in the neighborhood, increasing the forest carbon sink rate. Interestingly, species diversity and average RGR decreased when EcM or AM tree species predominated. Therefore, our study highlights that manipulating the BA ratio of EcM to AM tree species will play a nonnegligible role in maintaining biodiversity and increasing forest carbon sink rates.
In Vitro Polyploid Induction of Highbush Blueberry through De Novo Shoot Organogenesis
Authors: Marangelli Federico , Pavese Vera , Vaia Giuseppe , Lupo Michela , Bashir Muhammad Ajmal , Cristofori Valerio , Silvestri Cristian
Published: September 2022

Polyploid induction is of utmost importance in horticultural plants for the development of new varieties with desirable morphological and physiological traits. Polyploidy may occur naturally due to the formation of unreduced gametes or can be artificially induced by doubling the number of chromosomes in somatic cells. In this experiment, a protocol for in vitro polyploid induction of highbush blueberry (Vaccinium corymbosum L.) leaf tissues was studied by using different concentrations of colchicine and oryzalin. Oryzalin was found to be highly toxic to this species, while the adventitious shoot organogenesis media enriched with 25 and 250 µM colchicine was able to induce polyploidization, with significant differences among the treatments used. Higher concentrations of both antimitotic agents led to the browning and death of the leaf tissues. The polyploids obtained showed several morphological differences when compared with the diploid shoots. Flow cytometry analysis was used to confirm the ploidy level of the regenerated shoots, demonstrating that a total of 15 tetraploids and 34 mixoploids were obtained. The stomatal sizes (length and width) of the tetraploids were larger than those of the diploids, but a reduced stomatal density was observed as compared to the controls. These shoots will be acclimatized and grown until they reach the reproductive phase in order to test their potential appeal as new varieties or their use for breeding and genetic improvement.
Vibrational Emission Study of the CN and C2 in Nylon and ZnO/Nylon Polymer Using Laser-Induced Breakdown Spectroscopy (LIBS)
Authors: Alrebdi Tahani A. , Fayyaz Amir , Ben Gouider Trabelsi Amira , Asghar Haroon , Alkallas Fatemah H. , Alshehri Ali M.
Published: September 2022

The laser-induced breakdown spectroscopy (LIBS) technique was performed on polymers to study the neutral and ionic emission lines along with the CN violet system (B2Σ+ to X2Σ+) and the C2 Swan system (d3 Пg–a3 Пu). For the laser-based emission analyses, the plasma was produced by focusing the laser beam of a Q-switched Nd: YAG laser (2ω) at an optical wavelength of 532 nm, 5 ns pulse width, and a repetition frequency of 10 Hz. The integration time of the detection system was fixed at 1–10 ms while the target sample was positioned in air ambiance. Two organic polymers were investigated in this work: nylon and nylon doped with ZnO. The molecular optical emission study of nylon and doped nylon polymer sample reveals CN and C2 molecular structures present in the polymer. The vibrational emission analysis of CN and C2 bands gives information about the molecular structure of polymers and dynamics influencing the excitation structures of the molecules. Besides, it was further investigated that the intensity of the molecular optical emission structure strongly depends on the electron number density (cm−3), excitation temperature (eV), and laser irradiance (W/cm2). These results suggest that LIBS is a reliable diagnostic technique for the study of polymers regarding their molecular structure, identification, and compositional analysis.
Comparative Study on Thermal Response Mechanism of Two Binders during Slow Cook-Off
Authors: Wu Xinzhou , Li Jun , Ren Hui , Jiao Qingjie
Published: September 2022

The HTPE (hydroxyl-terminated polyether) propellant had a lower ignition temperature (150 °C vs. 240 °C) than the HTPB (hydroxy-terminated polybutadiene) propellant in the slow cook-off test. The reactions of the two propellants were combustion and explosion, respectively. A series of experiments including the changes of colors and the intensity of infrared characteristic peaks were designed to characterize the differences in the thermal response mechanisms of the HTPB and HTPE binder systems. As a solid phase filler to accidental ignition, the weight loss and microscopic morphology of AP (30~230 °C) were observed by TG and SEM. The defects of the propellant caused by the cook-off were quantitatively analyzed by the box counting method. Above 120 °C, the HTPE propellant began to melt and disperse in the holes, filling the cracks, which generated during the decomposition of AP at a low temperature. Melting products were called the “high-temperature self-repair body”. A series of analyses proved that the different thermal responses of the two binders were the main cause of the slow cook-off results, which were likewise verified in the propellant mechanical properties and gel fraction test. From the microscopic point of view, the mechanism of HTPE’s slow cook-off performance superior to HTPB was revealed in this article.
Adhesive Wear and Frictional Performance of Banana Fibre Reinforced Epoxy (BaFRE) Composite
Authors: Nirmal Umar
Published: September 2022

This current work is an attempt to investigate the tribological performance of banana fibre-reinforced epoxy (BaFRE) composite in dry contact conditions. The test is conducted on a wear test rig of type Block on Ring (BOR) based on ASTM G77, G137-95 standard. Different applied normal loads (5–30 N) subjected to a stainless steel counterface at different sliding speeds (1.7–3.96 m/s) and fixed sliding distance of 6.72 km were set as the experimental parameters. The test was conducted using neat epoxy (NE) as the control tests’ specimen while BaFRE composite was in anti-parallel (AP) and parallel (P) fibre strips orientation (O). The specific wear rate (Ws), friction coefficient, temperature variation and surface roughness (RA) of the NE and BaFRE composite in AP-O and P-O were investigated. The worn surface morphology of the test samples was examined under a high-resolution metallurgy microscope. The outcome of the work revealed that AP-O exhibited excellent wear performance when compared to P-O and NE. Moreover, the lowest friction coefficient of 0.0121 is achieved when AP-O is subjected to 30 N of applied load and 3.96 m/s of sliding velocity. BaFRE composite in AP-O demonstrated the lowest range of temperature variation when it was subjected to 30 N at 3.96 m/s of counterface sliding velocity. Due to the high shear resistance at the rubbing zone incurred by the AP-O test specimen and counterface, the RA values were remarkably high for the test specimen (i.e., 1.122 µm) and the counterface wear track zone (0.166 µm) as compared to the P-O and NE test samples. The predominant wear mechanism for the AP-O test specimen was plastic deformation, detached fibre, micro crack, minor fibre debonding and micro ploughing. In conclusion, there are improvements in terms of wear and friction performance of the composite when banana fibres are used as a reinforced element in epoxy resin. The improvement in Ws and friction coefficient for the AP test specimen was 29.4% and 48.6%, respectively, as compared to NE at 30 N of applied load, 6.72 km of sliding distance and 2.83 m/s of sliding speed.
Harnessing Lipid Polymer Hybrid Nanoparticles for Enhanced Oral Bioavailability of Thymoquinone: In Vitro and In Vivo Assessments
Authors: Imam Syed Sarim , Gilani Sadaf Jamal , Bin Jumah May Nasser , Rizwanullah Md. , Zafar Ameeduzzafar , Ahmed Mohammed Muqtader , Alshehri Sultan
Published: September 2022

The clinical application of phytochemicals such as thymoquinone (THQ) is restricted due to their limited aqueous solubility and oral bioavailability. Developing mucoadhesive nanocarriers to deliver these natural compounds might provide new hope to enhance their oral bioavailability. Herein, this investigation aimed to develop THQ-loaded lipid-polymer hybrid nanoparticles (THQ-LPHNPs) based on natural polymer chitosan. THQ-LPHNPs were fabricated by the nanoprecipitation technique and optimized by the 3-factor 3-level Box–Behnken design. The optimized LPHNPs represented excellent properties for ideal THQ delivery for oral administration. The optimized THQ-LPHNPs revealed the particles size (PS), polydispersity index (PDI), entrapment efficiency (%EE), and zeta potential (ZP) of <200 nm, <0.25, >85%, and >25 mV, respectively. THQ-LPHNPs represented excellent stability in the gastrointestinal milieu and storage stability in different environmental conditions. THQ-LPHNPs represented almost similar release profiles in both gastric as well as intestinal media with the initial fast release for 4 h and after that a sustained release up to 48 h. Further, the optimized THQ-LPHNPs represent excellent mucin binding efficiency (>70%). Cytotoxicity study revealed much better anti-breast cancer activity of THQ-LPHNPs compared with free THQ against MDA-MB-231 and MCF-7 breast cancer cells. Moreover, ex vivo experiments revealed more than three times higher permeation from the intestine after THQ-LPHNPs administration compared to the conventional THQ suspension. Furthermore, the THQ-LPHNPs showed 4.74-fold enhanced bioavailability after oral administration in comparison with the conventional THQ suspension. Therefore, from the above outcomes, mucoadhesive LPHNPs might be suitable nano-scale carriers for enhanced oral bioavailability and therapeutic efficacy of highly lipophilic phytochemicals such as THQ.
Experimental Investigation of the Tribological Behaviors of Carbon Fiber Reinforced Polymer Composites under Boundary Lubrication
Authors: Birleanu Corina , Pustan Marius , Pop Grigore , Cioaza Mircea , Popa Florin , Lazarescu Lucian , Contiu Glad
Published: September 2022

Friction and wear experiments were performed on carbon fiber-reinforced polymer (CFRP) composites, and the tribological behavior of these materials under boundary lubrication (based on the 5100 4T 10 W-30 engine oil with TiO2 Degussa P25 nanoparticles) was investigated. Experiments were carried out in two directions: one at a different normal load from 6 to 16 N and one at a low sliding speed of 110 mm/min under boundary lubrication conditions. The obtained results reveal the stick-slip effect and the static and dynamic coefficient of friction decreased slightly with increasing normal applied load on the carbon fiber reinforced polymer composite pairs. The second direction highlights through experimental tests on the pin on disc tribometer that the friction coefficient increases with the increase in normal load (20–80 N) and sliding velocity (0.4–2.4 m/s). On the other hand, it is found that the friction coefficient is slightly lower than in the stick-slip phase. During the running-in process, the friction coefficient of the CFRP pair increases steadily as the rubbing time increases, and after a certain rubbing period, it remains constant regardless of the material of the counter face. The obtained results show that for the observed interval, the influence of normal load and sliding velocity have relatively small fraction coefficients and low wear depths. A 3D analysis of the profile demonstrated the texture of wear marks and tracks of these engineering composite materials. Furthermore, the height variations of wear marks and the morphologies of the worn surfaces of specimens under boundary lubrication conditions were analyzed.
Anti-Freezing Nanocomposite Organohydrogels with High Strength and Toughness
Authors: Zheng Huijuan , Huang Qiqi , Lu Meijun , Fu Jiaxin , Liang Zhen , Zhang Tong , Wang Di , Li Chengpeng
Published: September 2022

Hydrogels based on nanocomposites (NC) structure have acquired a great deal of interest, but they are still limited by relatively low mechanical strength, inevitably losing elasticity when applied below subzero temperatures, due to the formation of ice crystallization. In this study, an anti-freezing and mechanically strong Laponite NC organohydrogel was prepared by a direct solvent replacement strategy of immersing Laponite NC pre-hydrogel into ethylene glycol (EG)/water mixture solution. In the organohydrogel, a part of water molecules was replaced by EG, which inhibited the formation of ice crystallization even at extremely low temperatures. In addition, the formation of hydrogen bonds between Laponite and the monomers of N-isopropylacrylamide (NIPAM) and hydroxyethyl acrylate (HEA) endowed the organohydrogels with high mechanical strength and toughness. The NC organohydrogel can maintain its mechanical flexibility even at −25 °C. The compressive stress, tensile stress, and elongation at the break of N5H5L reached 3871.71 kPa, 137.05 kPa, and 173.39%, respectively, which may be potentially applied as ocean probes in low temperature environment.
Effect of Crystallinity on Young’s Modulus of Porous Materials Composed of Polyethylene Terephthalate Fibers in the Presence of Carbon Dioxide
Authors: Aizawa Takafumi
Published: September 2022

Carbon dioxide (CO2)-assisted polymer compression method is used for plasticizing polymers with subcritical CO2 and then crimping the polymer fibers. Given that this method is based on crimping after plasticization by CO2, it is very important to know the degree of plasticization. In this study, heat treatment was gently applied on raw material fibers to obtain fibers with different degrees of crystallinity without changing the shape of the fibers. Simultaneously, two types of sheets were placed in a pressure vessel to compare the degree of compression and the degree of hardness. Furthermore, a model was used to derive the relative Young’s modulus of porous materials composed of polymer fibers with different degrees of crystallinity. In the model, the amount of strain was calculated according to the Young’s modulus as a function of porosity and reflected in compression. Young’s modulus of porous polymers in the presence of CO2 has been shown to vary significantly with slight differences in crystallinity, indicating that extremely low crystallinity is significant for plasticizing the polymer by CO2.
Influence of the Synergistic Effect of Multi-Walled Carbon Nanotubes and Carbon Fibers in the Rubber Matrix on the Friction and Wear of Metals during the Mixing Process
Authors: Wang Lin , Pan Yi , Chen Yihui , Qiu Jian , Du Aihua , Han Deshang , Wang Chuansheng
Published: September 2022

As a piece of high-intensity running equipment, the wear of an internal mixer determines the quality of rubber and its life. In general, the wear of an internal mixer is caused by the friction between the rubber and metal during the mixing process, and the most severe wear position is the end face of the equipment. In this paper, a mixture of multi-walled carbon nanotubes (MWCNTs) and carbon fibers (CFs) are added to rubber by mechanical compounding to obtain MWCNT/CF/carbon black (CB) composites. By investigating the synergistic mechanism of MWCNTs and CFs, we analyze the effect of the MWCNT/CF ratio on the frictional wear of metal on the end face of the internal mixer. At the microscopic level, MWCNTs and CFs form a spatial meshwork with CB particles through synergistic interactions. The CB particles can be adsorbed on the spatial meshwork to promote the dispersion of CB particles. In addition, the formation of oil film can be slowed down due to the spatial meshwork, which could hinder the spillage of aromatic oil. Meanwhile, the spatial meshwork serves as a physical isolation layer between the rubber and metal to reduce friction. Therefore, it dramatically impacts the dispersion degree of CB particles, the friction coefficient, the roughness of the surface, and the wear of metal. It shows that the synergistic effect of MWCNT/CF and CB particles is best when the CF content of the rubber matrix is 5 phr, showing the most stable spatial network structure, the best dispersion of CB particles, and minor wear on the end face of the internal mixer.
Biodegradability Assessment of Polyester Copolymers Based on Poly(ethylene adipate) and Poly(ε-caprolactone)
Authors: Atanase Leonard Ionut , Salhi Slim , Cucoveica Oana , Ponjavic Marijana , Nikodinovic-Runic Jasmina , Delaite Christelle
Published: September 2022

Biodegradable polymers contain chains that are hydrolytically or enzymatically cleaved, resulting in soluble degradation products. Biodegradability is particularly desired in biomedical applications, in which degradation of the polymer ensures clearance from the body and eliminates the need for retrieval or explant. In this study, a homologues series of poly(ε-caprolactone)-b-poly(ethylene adipate)-b-poly(ε-caprolactone) (PCL-b-PEA-b-PCL) block copolymers, with constant PEA molar mass and different PCL sequence lengths was obtained. The starting point of these copolymers was a dihydroxy-PEA precursor with a molar mass (Mn) of 2500 g/mol. Mn values of the PCL varied between 1000 and 10,000 g/mol. Both the precursors and the copolymers were characterized using different physicochemical methods, such as: NMR, SEC, Maldi-TOFF, DSC, and ATG. The molecular characteristics of the copolymers were in a direct correlation with the sequence length of the PCL. Enzymatic degradability studies were also conducted by using cell-free extract containing Pseudomonas aeruginosa PAO1 for 10 and 21 days, and it appeared that the presence of the PEA central sequence has an important influence on the biodegradability of the copolymer samples. In fact, copolymer PCL7000-PEA2500-PCL7000 had a weight loss of around 50% after 10 days whereas the weight loss of the homopolymer PCL, with a similar Mn of 14,000 g/mol, was only 6%. The results obtained in this study indicate that these copolymer samples can be further used for the preparation of drug delivery systems with modulated biodegradability.
Effect of Fiber Wrapping on Bending Behavior of Reinforced Concrete Filled Pultruded GFRP Composite Hybrid Beams
Authors: Gemi Lokman , Madenci Emrah , Özkılıç Yasin Onuralp , Yazman Şakir , Safonov Alexander
Published: September 2022

The application of pultruded fiber reinforced polymer (FRP) composites in civil engineering is increasing as a high-performance structural element or reinforcing material for rehabilitation purposes. The advantageous aspects of the pultrusion production technique and the weaknesses arising from the 0° fiber orientation in the drawing direction should be considered. In this direction, it is thought that the structural performance of the profiles produced by the pultrusion technique can be increased with 90° windings by using different fiber types. This paper presents experimental studies on the effect of FRP composite wrapping on the flexure performance of reinforced concrete (RC) filled pultruded glass-FRP (GFRP) profile hybrid beams with damage analysis. The hybrid beams are wrapped fully and partially with Glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) composites. Hybrid beam specimens with 0° to 90° fiber orientations were tested under three- and four-point bending loads. Based on the experimental load–displacement relationship results, initial stiffness, ductility, and energy dissipation capacity were compared. The experimental findings revealed that the maximum load-carrying capacities of beams produced with pultrude profiles increased by 24% with glass wrapping and 64.4% with carbon wrapping due to the change in the damages. A detailed damage analysis is provided. Similarly, significant increases were observed in structural performance ratios such as initial stiffness and ductility ratio.
Development of a Curcumin-Loaded Lecithin/Chitosan Nanoparticle Utilizing a Box-Behnken Design of Experiment: Formulation Design and Influence of Process Parameters
Authors: Walbi Ismail A. , Ahmad Mohammad Zaki , Ahmad Javed , Algahtani Mohammed S. , Alali Amer S. , Alsudir Samar A. , Aodah Alhassan H. , Albarqi Hassan A.
Published: September 2022

Curcumin (CUR) has impressive pharmacologic properties, including cardioprotective, neuroprotective, antimicrobial, and anticancer activity. However, the pharmaceutical application of CUR is limited due to its poor aqueous solubility and low bioavailability. The development of novel formulations has attracted considerable attention to the idea of applying nanobiotechnology to improve the therapeutic efficacy of these challenging compounds. In this study, CUR-loaded lecithin–chitosan nanoparticles (CUR/LCSNPs) were developed and optimized by the concentration of chitosan, lecithin, and stirring speed by a 3-factorial Box-Behnken statistical design, resulting in an optimal concentration of chitosan (A) and lecithin (B) with a 1200 rpm stirring speed (C), with applied constraints of minimal average particle size (Y1), optimal zeta potential (Y2), and maximum entrapment efficiency (%EE) (Y3). The mean particle size of the checkpoint formulation ranged from 136.44 ± 1.74 nm to 267.94 ± 3.72, with a zeta potential of 18.5 ± 1.39 mV to 36.8 ± 3.24 mV and %EE of 69.84 ± 1.51% to 78.50 ± 2.11%. The mean particle size, zeta potential, %EE, and % cumulative drug release from the optimized formulation were 138.43 ± 2.09 nm, +18.98 ± 0.72 mV, 77.39 ± 1.70%, and 86.18 ± 1.5%, respectively. In vitro drug release followed the Korsmeyer–Peppas model with Fickian diffusion (n < 0.45). The optimized technique has proven successful, resulting in a nanoformulation that can be used for the high loading and controlled release of lipophilic drugs.
Continuous Systems Bioremediation of Wastewaters Loaded with Heavy Metals Using Microorganisms
Authors: Filote Cătălina , Roșca Mihaela , Simion Isabela Maria , Hlihor Raluca Maria
Published: September 2022

Heavy metal pollution is a serious concern of the modern era due to its widespread negative effects on human health and to the environment. Conventional technologies applied for the uptake of this category of persistent pollutants are complex, often expensive, and inefficient at low metal concentrations. In the last few years, non-conventional alternatives have been studied in search of better solutions in terms of costs and sustainability. Microbial adsorbents are one of the biomass-based sorbents that have extensively demonstrated excellent heavy metals removal capacity even at low concentrations. However, most of the carried-out research regarding their application in wastewater treatment has been performed in discontinuous systems. The use of microorganisms for the uptake of metal ions in continuous systems could be an important step for the upscale of the remediation processes since it facilitates a faster remediation of higher quantities of wastewaters loaded with heavy metals, in comparison with batch systems removal. Thus, the current research aims to analyze the available studies focusing on the removal of metal ions from wastewaters using microorganisms, in continuous systems, with a focus on obtained performances, optimized experimental conditions, and the sustainability of the bioremoval process. The present work found that microbial-based remediation processes have demonstrated very good performances in continuous systems. Further sustainability analyses are required in order to apply the bioremediation technology in an optimized environmentally friendly way in large-scale facilities.
Process Model Inversion in the Data-Driven Engineering Context for Improved Parameter Sensitivities
Authors: Selvarajan Subiksha , Tappe Aike Aline , Heiduk Caroline , Scholl Stephan , Schenkendorf René
Published: September 2022

Industry 4.0 has embraced process models in recent years, and the use of model-based digital twins has become even more critical in process systems engineering, monitoring, and control. However, the reliability of these models depends on the model parameters available. The accuracy of the estimated parameters is, in turn, determined by the amount and quality of the measurement data and the algorithm used for parameter identification. For the definition of the parameter identification problem, the ordinary least squares framework is still state-of-the-art in the literature, and better parameter estimates are only possible with additional data. In this work, we present an alternative strategy to identify model parameters by incorporating differential flatness for model inversion and neural ordinary differential equations for surrogate modeling. The novel concept results in an input-least-squares-based parameter identification problem with significant parameter sensitivity changes. To study these sensitivity effects, we use a classic one-dimensional diffusion-type problem, i.e., an omnipresent equation in process systems engineering and transport phenomena. As shown, the proposed concept ensures higher parameter sensitivities for two relevant scenarios. Based on the results derived, we also discuss general implications for data-driven engineering concepts used to identify process model parameters in the recent literature.
Dunaliella salina as a Potential Biofactory for Antigens and Vehicle for Mucosal Application
Authors: Castellanos-Huerta Inkar , Gómez-Verduzco Gabriela , Tellez-Isaias Guillermo , Ayora-Talavera Guadalupe , Bañuelos-Hernández Bernardo , Petrone-García Víctor Manuel , Fernández-Siurob Isidro , Garcia-Casillas Luis Alberto , Velázquez-Juárez Gilberto
Published: September 2022

The demand for effective, low-cost vaccines increases research in next-generation biomanufacturing platforms and the study of new vaccine delivery systems (e.g., mucosal vaccines). Applied biotechnology in antigen production guides research toward developing genetic modification techniques in different biological models to achieve the expression of heterologous proteins. These studies are based on various transformation protocols, applied in prokaryotic systems such as Escherichia coli to eukaryotic models such as yeasts, insect cell cultures, animals, and plants, including a particular type of photosynthetic organisms: microalgae, demonstrating the feasibility of recombinant protein expression in these biological models. Microalgae are one of the recombinant protein expression models with the most significant potential and studies in the last decade. Unicellular photosynthetic organisms are widely diverse with biological and growth-specific characteristics. Some examples of the species with commercial interest are Chlamydomonas, Botryococcus, Chlorella, Dunaliella, Haematococcus, and Spirulina. The production of microalgae species at an industrial level through specialized equipment for this purpose allows for proposing microalgae as a basis for producing recombinant proteins at a commercial level. A specie with a particular interest in biotechnology application due to growth characteristics, composition, and protein production capacity is D. salina, which can be cultivated under industrial standards to obtain βcarotene of high interest to humans. D saline currently has advantages over other microalgae species, such as its growth in culture media with a high salt concentration which reduces the risk of contamination, rapid growth, generally considered safe (GRAS), recombinant protein biofactory, and a possible delivery vehicle for mucosal application. This review discusses the status of microalgae D. salina as a platform of expression of recombinant production for its potential mucosal application as a vaccine delivery system, taking an advance on the technology for its production and cultivation at an industrial level.
Classification of Droplets of Water-PVP Solutions with Different Viscosity Values Using Artificial Neural Networks
Authors: Mrad Mohamed Azouz , Csorba Kristof , Galata Dorián László , Nagy Zsombor Kristóf
Published: September 2022

When a liquid flows, it has an internal resistance to flow. Viscosity is the property that measures this resistance, which is a fundamental characteristic parameter of liquids. The monitoring of viscosity is essential for quality control in many industrial areas, such as the pharmaceutical, chemical, and energy-related industries. Several instruments measure the viscosity of a liquid, the most used being the capillary viscometers. These instruments are complex, associated with high cost and expensive prices. This represents a challenge in several industries, where accurate viscosity knowledge is essential in designing various industrial equipment and processes. Using image processing and machine learning algorithms is a promising alternative to the current measurement methods. This work aims to extract characteristic information from videos of droplets of different samples using image processing algorithms. An Artificial Neural Network model utilizes the extracted characteristics to classify the droplets in the correct category, which is correlated with the viscosity of the sample. Different solutions samples were created using different ratios of Water and PVP (Polyvinylpyrrolidone) and videos of their droplets were taken and processed. It was found that for water-PVP solutions, the proposed ANN model was able to successfully classify the droplets using the data extracted from the videos with high accuracy. The results imply that the ANN model can recognize the features that affect the viscosity values.
Testing and Analysis of Torsional Vibration of Ship Transmission Shafting Based on Five-Point Smoothing Algorithm
Authors: Wang Fei , Liao Jianbin , Huang Chaoming , Li Hanlin , Cao Jiayu , Yu Hongliang , Yan Jin
Published: September 2022

In this paper, a method is proposed to accurately measure the torsional vibration of a ship’s propulsion shafting, and calculate its instantaneous torque based on instantaneous speed data. The instantaneous speed signal of a ship is measured by a data acquisition instrument indirectly under the deceleration condition, and then filtered by the five-point smoothing algorithm. The filtered instantaneous speed signal is further processed to calculate the maximum amplitude of the torsional vibration, along with the maximum torque of the propulsion shafting under specific operating conditions. The proposed method can effectively improve the calculation accuracy of the torsional vibration of the shafting, and provides reliable theoretical basis for setting the safe speed of the ship’s diesel engine.
Metallic B2C3P Monolayer as Li-Ion Battery Materials: A First-Principles Study
Authors: Zhou Dawei , Wang Zhuo , Cheng Jinbing , Pu Chunying
Published: September 2022

The search for and design of high-performance electrode materials is always an important topic in rechargeable batteries. Using a global structure prediction method together with first-principles calculations, a free-standing two-dimensional B2C3P monolayer with honeycomb structure was identified. The stability of the B2C3P monolayer was confirmed by cohesive energy, phonon curves, and ab initio molecular dynamics calculations. Of note, the B2C3P monolayer was demonstrated to be metallic, which shows excellent performance for Li-ion batteries. For example, the B2C3P monolayer also exhibited a metallic characteristic after Li adsorption, therefore the ability to keep good electrical conductivity during battery operation. Furthermore, when a B2C3P monolayer is used as a lithium-ion battery anode, it shows an ultra-high theoretical capacity of 3024 mAh/g, and a comparatively low diffusion barrier of 0.33 eV. All calculated results showed that the B2C3P monolayer is an appealing anode material, and has great potential in energy storage devices.
The Effects of Vitamin E Analogues α-Tocopherol and γ-Tocotrienol on the Human Osteocyte Response to Ultra-High Molecular Weight Polyethylene Wear Particles
Authors: Ormsby Renee , Hosaka Kunihiro , Evdokiou Andreas , Odysseos Andreani , Findlay David , Solomon Lucian , Atkins Gerald
Published: September 2022

Polyethylene (PE) liners are a common bearing surface of orthopaedic prostheses. Wear particles of ultra-high molecular weight PE (UHMWPE) contribute to periprosthetic osteolysis, a major cause of aseptic loosening. Vitamin E is added to some PE liners to prevent oxidative degradation. Osteocytes, an important cell type for controlling both bone mineralisation and bone resorption, have been shown to respond UHMWPE particles by upregulating pro-osteoclastogenic and osteocytic osteolysis. Here, we examined the effects of the vitamin E analogues α-tocopherol and γ-tocotrienol alone or in the context of UHMWPE particles on human osteocyte gene expression and mineralisation behaviour. Human osteoblasts differentiated to an osteocyte-like stage were exposed to UHMWPE wear particles in the presence or absence of either α-Tocopherol or γ-Tocotrienol. Both α-Tocopherol and γ-Tocotrienol induced antioxidant-related gene expression. UHMWPE particles independently upregulated antioxidant gene expression, suggesting an effect of wear particles on oxidative stress. Both vitamin E analogues strongly induced OPG mRNA expression and γ-Tocotrienol also inhibited RANKL mRNA expression, resulting in a significantly reduced RANKL:OPG mRNA ratio (p < 0.01) overall. UHMWPE particles reversed the suppressive effect of α-Tocopherol but not of γ-Tocotrienol on this pro-osteoclastogenic index. UHMWPE particles also upregulated osteocytic-osteolysis related gene expression. Vitamin E analogues alone or in combination with UHMWPE particles also resulted in upregulation of these genes. Consistent with this, both vitamin E analogues promoted calcium release from mineralised cultures of osteocyte-like cells. Our findings suggest that while vitamin E may suppress osteocyte support of osteoclastogenesis in the presence of UHMWPE particles, the antioxidant effect may induce osteocytic osteolysis, which could promote periprosthetic osteolysis. It will be important to conduct further studies of vitamin E to determine the long-term effects of its inclusion in prosthetic materials.