bluuebunny/crossref_metadata_2025_split huggingface dataset:
The synergistic impacts of hybrid nanofillers of graphene nanoplatelets/carbon nanotubes on curing behavior of an epoxy‐vinyl ester interpenetrating polymer network nanocomposite coating
Authors: Molaei Afrooz , Jannesari Ali 
Published: September 2023

AbstractThis study investigated the synergistic effects of hybrid graphene nanoplatelet (GnP)/multi walled carbon nanotube (MWCNT) nanofillers at various loadings on the kinetics of curing of the epoxy (EP)/vinyl ester (VE) interpenetrating polymer network (IPN) system, with a mass ratio of 1:1. Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analyzer (DMTA) and differential scanning calorimetry (DSC) were used to monitor the interpenetration process of EP and VE and likely interactions between the components of the different resin systems in IPN. The curing behavior of all prepared samples under non‐isothermal conditions was studied using DSC at four heating rates. Two different isoconversional approaches were applied to evaluate the reaction kinetics, that is, the Friedman and the advanced Vyazovkin methods. The obtained activation energy curves for all samples revealed a complex curing behavior involving three stages; early IPN stage, IPN growth stage, and late IPN stage. Then, the activation energy values for each reaction step were determined based on the Friedman method. The presence of GnP/MWCNT nanoparticles showed no catalytic effect on the reaction of VE with methyl ethyl ketone peroxide (MEKP). In contrast, incorporating GnP/MWCNT nanoparticles significantly decreases the activation energy values of the reaction of ring opening of epoxides with methyl tetrahydrophthalic anhydride (MTHPA) 1‐methyl imidazole (‐Mi) and the reaction of esterification of the hydroxyl groups of VE with MTHPA.Highlights
Model‐free methods used to curing study of epoxy‐vinyl ester IPN nanocomposites
FTIR, DSC and DMTA used for evaluation IPN formation of EP/VE
It showed that the improvement of dispersion and compatibility by using of GnP/MWCNT hybrid
Frideman and Vyazovkin methods used to calculate Ea of nanocomposites
DSC thermograms were deconvoluted into three individual peaks.
Understanding significantly reinforced polymethyl methacrylate composites induced by two‐dimensional Tin+1Cn from an atomistic perspective
Authors: He Liangze , Li Chenliang , Lv Kezhen , Ding Xiaomin , Feng Liyang , Lv Xiaolong 
Published: September 2023

AbstractMXenes, which have good reinforcing and toughening effects, can serve as excellent polymer additives. However, the mechanism whereby MXenes act has not been revealed. In this study, to understand the reinforcement effect of Tin+1Cn on polymethyl methacrylate (PMMA) from an atomistic perspective, we used molecular dynamics to conduct unidirectional tensile simulations of PMMA composites reinforced with monolayer Ti2C and Ti3C2 sheets. The results showed that Ti3C2 can more significantly improve the mechanical properties of the PMMA polymer than Ti2C, and the yield stress and Young's modulus of the Ti3C2/PMMA complexes were respectively 54.39% and 73.46% higher than the Ti2C/PMMA complexes. To further reveal the interaction mechanism between Tin+1Cn and PMMA, different separation speeds were used to simulate the pull‐out of Tin+1Cn from the PMMA matrix. The results showed that, in addition to the enhancement of interfacial strength by non‐bonding van der Waals forces, there were TiO and CTi bonds between Tin+1Cn and PMMA, which further increased the interfacial strength. Ti3C2 formed a denser interfacial region with PMMA, it could more effectively resist the formation and expansion of cracks. These findings may provide an important theoretical basis to design new type of MXene/polymer composites with excellent mechanical properties.Highlights
MXene greatly improved the mechanical properties of the PMMA matrix.
Formation of chemical bonds improved connection between the MXene and PMMA.
The addition of MXene slows down the rate of crack propagation in PMMA.
Nanoscale hydroxyapatite/chitosan polymer coatings: Synthesis and characterization
Authors: Saeedi Fateme , Montazeri Arash 
Published: September 2023

AbstractThe present work involves the coating synthesis of nano‐hydroxyapatite/chitosan (nHA/CS) on a Mg‐2 wt% Zn scaffold with the pulse electrodeposition (PED) technique. In practice, to render coatings more corrosion‐resistant and biocompatibility in simulated body fluids, the impact of PED factors, such as mean current density (j), a duty cycle, and coating duration (t), was investigated. Further, Fourier transform infrared spectroscopy, scanning electron microscope, x‐ray diffraction, energy‐dispersion spectrometer, and water contact angle (WCA) were studied to characterize coatings. The corrosion resistance of coatings was investigated by impedance evaluations and potentiodynamic polarization. The results obtained from analyses revealed that the optimum conditions for synthesizing the nHA/CS coating were achieved when applying j = 20 mA/cm2, a duty cycle = 0.4, and a duration of 60 minutes. The coatings' microstructure and Ca/P ratio were influenced by PED factors, which included nano spherical‐shaped and 1.65. Furthermore, the corrosion rate was decreased from 19.603 to 1.492 mm yr−1 after being modified by optimum coating. Moreover, the high hydrophilic properties are assigned to this coating with a WCA of 29.9 compared to other coatings and the Mg scaffold. The biological properties of the optimum coating were assessed through in‐vitro experiments involving MG63 cells, which included the evaluations of cell adhesion and cytotoxicity. The results obtained from the corrosion and in‐vitro experiments indicate that the nanocomposite coating, upon optimization, holds potential as a scaffold for bone tissue engineering.Highlights
Using Mg‐2 wt% Zn scaffold as a substrate for nanocomposite coatings.
Pulse electrodeposition method for the synthesis of nano‐hydroxyapatite/chitosan (nHA/CS) coatings.
Pulse electrodeposition (PED) method to modify morphology, corrosion resistance, and biocompatibility.
Optimum PED parameters: j = 20 mA/cm2, duty cycle = 0.4, and t = 60 min.
Monocyte and neutrophil to lymphocyte ratios in hospitalized children with RSV bronchiolitis
Authors: Burrack Nitzan , Adar Assaf , Goldbart Aviv , Weissmann Sarah , Cohen Bracha , Hazan Itai , Horev Amir , Golan‐Tripto Inbal 
Published: September 2023

AbstractObjectiveAcute bronchiolitis is the most common cause of hospitalization in young children. Data on monocyte‐to‐lymphocyte‐ratio (MLR) and neutrophil‐to‐lymphocyte‐ratio (NLR) as biomarkers are limited. We aim to evaluate these ratios in children hospitalized with respiratory syncytial virus (RSV) bronchiolitis and their value as biomarkers for severe clinical outcomes.Study DesignA single‐center retrospective cohort study of children aged <2 years hospitalized due to RSV bronchiolitis, between January 2018 and March 2022, with a complete blood count upon admission. We divided the cohort into quartiles based on MLR and NLR values. We examined associations between quartiles and four clinical severity outcomes.ResultsA total of 2038 children (median age: 4.4 months, IQR: 1.9−9.8) were included in the study. The median MLR and NLR values for quartiles 1−4 were 0.14, 0.22, 0.30, 0.47, and 0.37, 0.70, 1.16, 2.29, respectively. Children with higher MLR had higher hospitalization rates to the pediatric intensive care unit (PICU) (Q1 2.4%, Q4 9.4%, p < .001), extended hospital stays (Q1 19.4%, Q4 32%, p < .001), and lower minimal oxygen saturation (Q1 90%, Q4 87%, p < .001). Cut‐off values of 0.34 for MLR and 0.67 for NLR optimally identified PICU admissions. In a model accounting for age and sex, the fourth MLR quartile had an RR of 3.4 (95% CI: 1.76−7.22) and successfully predicted PICU admissions (area under the curve = 0.73; 95% CI: 0.681−0.789).ConclusionsMLR and NLR are potential biomarkers for identifying children with RSV bronchiolitis at a higher risk for severe outcomes, specifically PICU admission.
Insights into the solution structure and transcriptional regulation of the MazE9 antitoxin in Mycobacterium tuberculosis
Authors: Roy Tanaya Basu , Sarma Siddhartha P. 
Published: September 2023

AbstractThe present study endeavors to decode the details of the transcriptional autoregulation effected by the MazE9 antitoxin of the Mycobacterium tuberculosis MazEF9 toxin–antitoxin system. Regulation of this bicistronic operon at the level of transcription is a critical biochemical process that is key for the organism's stress adaptation and virulence. Here, we have reported the solution structure of the DNA binding domain of MazE9 and scrutinized the thermodynamic and kinetic parameters operational in its interaction with the promoter/operator region, specific to the mazEF9 operon. A HADDOCK model of MazE9 bound to its operator DNA has been calculated based on the information on interacting residues obtained from these studies. The thermodynamics and kinetics of the interaction of MazE9 with the functionally related mazEF6 operon indicate that the potential for intracellular cross‐regulation is unlikely. An interesting feature of MazE9 is the cis ⇌ trans conformational isomerization of proline residues in the intrinsically disordered C‐terminal domain of this antitoxin.
Physiologically based mechanistic insight into differential risk of valproate hepatotoxicity between children and adults: A focus on ontogeny impact
Authors: Huang Yu‐Ting , Huang Yen‐Ming , Kung Fan‐Lu , Lin Chun‐Jung , Jao Tun , Ho Yunn‐Fang 
Published: September 2023

AbstractThe anticonvulsant valproic acid (VPA) despite complex pharmacokinetics has been in clinical use for nearly 6 decades. Previous reports indicated neonates, infants, and toddlers/preschoolers had higher risk of valproate hepatotoxicity than adults. However, dosing recommendations for those less than 10 years of age are lacking. To decipher clinical puzzles, physiologically‐based pharmacokinetic (PBPK) models of VPA and its hepatotoxic metabolite 4‐ene‐VPA were constructed and simulated with particularly integrated information of drug‐metabolizing enzyme ontogeny. Adult and pediatric PK data of VPA (n = 143 subjects) and 4‐ene‐VPA (n = 8 subjects) collected from previous reports were used for model development and validation. Sensitivity analyses were performed to characterize ontogeny impacts of CYP2C9 and UGT2B7 on dispositions of VPA and 4‐ene‐VPA across age groups. Optimal VPA dosing for each pediatric age group was also predicted and objectively judged by ensuring VPA efficacy and avoiding 4‐ene‐VPA hepatotoxicity. The study revealed UGT2B7 ontogeny was quite influential on VPA clearance even in neonates and small children. Intrinsic clearance of CYP2C9 was the most prominent determinant for areas under the concentration‐time curve of VPA and 4‐ene‐VPA in infants, and toddlers/preschoolers, reflecting higher hepatotoxicity risk due to noxious 4‐ene‐VPA accumulation in these groups. The ontogeny‐based PBPK approach complements conventional allometric methods in dosing estimation for the young by providing more mechanistic insight of the processes changing with age. The established ontogeny‐based PBPK approach for VPA therapy deserves further corroboration by real‐world therapeutic data to affirm its clinical applicability.
Cinnamaldehyde inhibits cytokine storms induced by the ORF3a protein of SARS‐CoV‐2 via ROS‐elimination in activated T cells
Authors: Ma Jing , Chen Xu , Xue Rui , Wang Fei , Dong Jun , Tao Ning , Qin Zhihai 
Published: September 2023

AbstractCytokine storms are the cause of complications in patients with severe COVID‐19, and it becomes the target of therapy. Several natural compounds were selected to screen the inhibitory effect on T‐cell proliferation by Fluorescence‐Activated Cell Sorting (FACS) and cytokine production by enzyme‐linked immunosorbent assay (ELISA). Open reading frame 3a (ORF3a) of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) stimulates the specific T‐cell activation model in vivo and in vitro. The coculture system included the macrophage cell line RAW264.7 and splenocytes. Reactive oxygen species (ROS) levels and glycolysis in T cells were evaluated. Cinnamaldehyde effectively inhibits cytokine storms both in vitro and in vivo. It decreased inflammatory cytokine (such as IFN‐γ, TNF‐α, IL‐6, and IL‐2) production by murine peripheral blood cells upon direct stimulation with ConA, after immunization with the MHV‐A59 virus or ORF3a peptide from SARS‐CoV‐2. Cinnamaldehyde restored the percentage of T cells, which was originally decreased in the peripheral blood and splenocytes of ORF3a‐immunized mice. In a coculture system, cinnamaldehyde reduced the secretion of inflammatory cytokines from macrophages in a T‐cell dependent manner. Furthermore, cinnamaldehyde decreased the ROS level in activated T cells, which in turn reduced glycolysis and the activation of T cells. Cinnamaldehyde can be used as a candidate molecule for COVID‐19.
Prescribed performance event‐triggered control for MIMO switched nonlinear systems with unstable subsystems
Authors: Fan Zhida , Wang Fenglan , Long Lijun 
Published: September 2023

AbstractThis article investigates the problem of prescribed performance event‐triggered tracking control for a class of multi‐input‐multi‐output (MIMO) switched uncertain nonlinear systems, in which the solvability of the prescribed performance event‐triggered control problem for each subsystem is unnecessary. By developing a proper switching law, a prescribed performance event‐triggered low‐complexity state‐feedback control method is set up to solve the problem. Furthermore, the result above is extended to MIMO switched uncertain nonlinear systems with unavailable states by developing a prescribed performance event‐triggered low‐complexity output‐feedback control and a high‐gain observer. Also, Zeno phenomenon for the event‐triggered mechanism and the switching law is excluded. Finally, two examples verify the results obtained.
Quantum Design and Synthesis of a Gasoline Marker Based on a Phenol‐Functionalized Supramolecular Quaternary‐Salt Complex
Authors: Soto‐Castruita Enrique , Cisneros‐Dévora Rodolfo , Cerón‐Camacho Ricardo , Ramírez‐Pérez Jorge‐Francisco , Servín‐Nájera Ana‐Graciela , Oviedo‐Roa Raúl , Martínez‐Magadán José‐Manuel , Beltrán Hiram‐Isaac , Zamudio‐Rivera Luis‐S. 
Published: September 2023

AbstractWe present the development of supramolecular surfactants (SSs) based on MR⋅⋅⋅OA⋅⋅⋅(PhOH)i complexes among methylene red (MR), oleyl amine (OA) and stoichiometric amounts
of phenol (PhOH), aimed at obtaining markers for the identification of gasolines by harnessing their supramolecular interactions‐mediated stability and homogeneous distribution within gasoline, as well as their very‐characteristic nuclear magnetic resonance (NMR), Fourier‐transform infrared (FTIR), and UV‐visible (UV‐vis) signals. Density functional theory (DFT), together with the conductor‐like screening model (COSMO), reveal that the supramolecular interactions are due to a non‐ionic to ionic reaction under which the carboxylic proton is transferred from MR to OA, and that PhOH confers solubility to SSs withing gasoline by hiding their ionic heads. The proton transference was confirmed by 1H NMR and 13C NMR, FTIR, and thermogravimetric analysis spectroscopies, whereas the solubility in gasoline through UV‐vis absorbance measurements that, together with viscosity measurements, also revealed that the maximum content of PhOH for adequate performance is
3, in agreement with DFT‐COSMO calculations, which predict that for
3 the SSs’ interaction energy per additional PhOH becomes weaker. All theoretical and experimental results support the viability of MR⋅⋅⋅OA⋅⋅⋅(PhOH)i complexes as gasoline markers due to their full compatibility with gasoline and their well‐defined spectroscopic‐fingerprints.
Organocatalysts for the Asymmetric Neber reaction: Synthesis of Chiral 2‐(Tetrazol‐5‐yl)‐2H‐Azirines
Authors: Alves Cláudia , Sase Terver J. , Gadelho Cristina , Murtinho Dina , S. Serra M. Elisa , Cardoso Ana L. , Pinho e Melo Teresa M. V. D. 
Published: September 2023

Abstract‐ Several novel organocatalysts derived from β‐ and γ‐lactam‐fused thiazolidines and L‐phenylalanine‐based thiazolidines were efficiently synthetized. These organocatalysts, as well as other previously developed thiazolidine‐derived thioureas, were tested in the asymmetric one‐pot Neber reaction of β‐ketoxime‐1H‐tetrazoles towards chiral 2‐(tetrazol‐5‐yl)‐2H‐azirines. The results obtained when using thioureas only differing in the lactam ring size demonstrate that the presence of the 6β‐lactam ring in the catalysts is a requirement to achieve high enantioselectivity in the studied transformation. The new 6β‐aminopenicillanic acid‐derived thiourea afforded the R enantiomer of 3‐phenyl‐2‐(tetrazol‐5‐yl)‐2H‐azirine with >99 % ee.
Nanofiber‐Reinforced Composite Gel Enabling High Ionic Conductivity and Ultralong Cycle Life for Zn Ion Batteries
Authors: Hu Wei , Zhang Yixuan , Ju Jingge , Wang Yuanyuan , Zhang Zehao , Kang Weimin 
Published: September 2023

AbstractDespite the impressive merits of gel electrolytes for aqueous Zn‐ion batteries, it remains a significant challenge to design and develop the gel electrolyte with high ionic conductivity, excellent dimensional stability, and long cycle life. Herein, a composite electrolyte (PTP) with thermolastic polyurethane ‐poly(m‐phenylene isophthalamide) nanofiber‐reinforced polyvinyl alcohol gel strategy is proposed for highly reversible Zn plating/stripping. Mechanically robust and ultrathin PTP contains functional groups for building ion migration channels and immobilizing water molecules, which accelerates Zn2+ migration and mitigates water‐related side reactions. Thus, the Zn anodes exhibit excellent electrochemical performance involving high cycling stability (6500 h at 5 mA cm−2, 5 mA h cm−2) and achieving an exceptional cumulative capacity of more than 16 000 mA h cm−2. This enhancement is well maintained when combined with MnO2 cathode. This work provides a reasonable solution for stabilizing Zn anodes and also provides new ideas for the modification of nanofiber‐reinforced gel electrolytes.
Equilibrium and Non‐equilibrium Reaction Schemes for Prebiotic Polymerization of Ribonucleotides
Authors: Kitson Varun , Sanders Quentin , Dass Avinash V. , Higgs Paul G. 
Published: September 2023

AbstractThe RNA World theory for the origin of life requires polymers to be generated initially by abiotic reactions. Experiments have studied polymerization of 5′‐monophosphates, 2′,3′‐cyclic phosphates, and 5′‐triphosphates. We consider theoretical models of polymerization in solution illustrating the differences between these cases. We consider (i) a basic model where all monomers undergo reversible joining and breaking; (ii) a model where 2′,3′‐cyclic phosphates can join, and breaking regenerates the cyclic phosphate; (iii) a model where 5′‐triphosphates can join irreversibly, in addition to the joining and breaking of 2′,3′‐cyclic phosphates. In cases (i) and (ii) there is an equilibrium steady state with balance between making and breaking bonds. In case (iii) there is a circular reaction flux in which monomers are activated by an external phosphate source, activated monomers form polymers, and polymers break to release non‐activated monomers. The mean length can be calculated as a function of concentration. In case (iii), the mean length switches from a low‐concentration regime controlled by the 5′‐triphosphates to a high‐concentration regime controlled by the 2′,3′‐cyclic phosphates. The circular reaction flux is reminiscent of a metabolism. If formation of 5’‐triphosphates was already in place for RNA synthesis, ATP could subsequently been coopted for metabolism.
Development of an eco‐friendly technology for biodiesel production by Spirulina sp. isolated from pond water
Authors: Mahendran Shunmugiah , Sethuraman Mariswaran , Wilson Jeyaraj John , Muniasamy Samuthirapandi , Sivakumar Thangavel , Ponmanickam Ponnirul 
Published: September 2023

AbstractBiodiesel made from renewable energy sources is gaining popularity due to its environmental and economic benefits. In this work, the effect of the most important reaction variables was investigated during the acid‐catalyzed of Spirulina sp. microalgae oil to biodiesel. Results showed that the biodiesel was obtained at 60°C for 8 h using 30 g of dry Spirulina sp. powder in 300 mL of n‐hexane. Physical characteristics of the biodiesel produced from Spirulina sp. were confirmed using, evaporation temperature, flash point, freeze point, and fire point. The presence of bonds of CH3, ROH, RC≡C‐H, ‐CH = CH‐CH2)n, R‐CH2‐X, and ArOH in the biodiesel 1H NMR spectrum. Further, the biodiesel produced from the Spirulina sp. subjected to FT‐IR and GC MS which revealed the aliphatic hydrocarbons and the list of compounds such as Oleic acid, 9‐octadecenal etc.
Opinions of Turkish veterinarians on the termination of unwanted pregnancies in dogs
Authors: Özen Abdullah , Yerlikaya Şaşmaz Onur , Çavuş Alan Seda 
Published: September 2023

AbstractBackgroundNo time constraints exist in Turkish veterinary law regarding the termination of unwanted pregnancies in dogs. Having undergone limited ethical debate, opinions on this issue vary among veterinarians. This study aimed to determine appropriate indications accepted by veterinary practitioners for the termination of unwanted pregnancies in dogs and the cut‐off point preferred by these professionals for performing this medical and surgical intervention.MethodsA qualitative methodology was used for the collection of the data. Interviews were conducted with 40 veterinarians (13 practitioners and 27 academics).ResultsThe main reasons for performing pregnancy termination were ‘institutional obligations’ and ‘demand of the animal owner’. Meanwhile, the cut‐off points for veterinarians were ‘possibility of pregnancy’, ‘implantation/diagnosability/visibility’, ‘heartbeat’ and ‘viability’.LimitationsThe inclusion of ethics experts among the authors may have caused bias in the comments of the participants on ethical issues.ConclusionThe fact that animals are legally relegated to the custody of humans not only adds a unique character to the veterinary ethical debate but also creates a comfort zone for veterinarians not willing to examine compelling ethical issues.
Survival to discharge and outcome of a dog following out‐of‐hospital cardiac arrest due to asphyxiation
Authors: Lang Kathrin , Crawford Abbe H. , Hall Georgina B. F. , Humm Karen 
Published: September 2023

AbstractA 7‐month‐old dog presented with a 10‐minute history of upper respiratory tract obstruction and secondary loss of consciousness in the minute before its arrival to the hospital. The dog was found to be dead on arrival. Cardiopulmonary resuscitation was initiated, which led to successful return of spontaneous circulation 20 minutes later, with subsequent regain of consciousness. Symptomatic therapy and supportive care were provided for 3.5 weeks before discharging the dog into the care of its owners. Despite having made an initial improvement, it was subsequently euthanised 4 weeks later due to persistent severe neurological deficits. Although the neurological improvement was not deemed sufficient for the dog to have a good quality of life, this case report highlights that return of spontaneous circulation after out‐of‐hospital cardiac arrest and a prolonged period of cardiopulmonary resuscitation is feasible, and neurological improvement thereafter is possible.