bluuebunny/crossref_metadata_2025_split huggingface dataset:
TFE Terpolymers: Once Promising – Are There Still Perspectives in the 21st Century: Synthesis, Characterization, and Properties‐Part I
Authors: Ok Salim , Steinhart Martin , Scheler Ulrich , Améduri Bruno 
Published: August 2024

AbstractPolytetrafluoroethylene (PTFE) exhibits outstanding properties such as high‐temperature stability, low surface tension, and chemical resistance against most solvents, strong acids, and bases. However, these traits make it challenging to subject PTFE to standard polymer processing procedures, such as thermoforming and hot incremental forming. While polymer processing at temperatures above the melting point of PTFE is already demanding, the typically large molar mass of PTFE results in extremely high melt viscosities, complicating the processing of PTFE. Also, PTFE tends to decompose at temperatures close to its melting point. Therefore, fluoropolymers obtained by copolymerizing tetrafluoroethylene (TFE) with various co‐monomers are studied as alternatives to PTFE (e.g., fluorinated ethylene‐propylene (FEP)), combining its advantages with better processability. TFE terpolymers have emerged as desirable PTFE alternatives. This review provides an overview of the synthesis with various comonomers and microstructural analysis of PTFE terpolymers and the relationships between the microstructures of TFE terpolymers and their properties.
Complex Sequence‐Defined Heteropolymers Enable Controlled Film Growth in Layer‐By‐Layer Assembly
Authors: Barman Ranajit , Tschopp Michel , Charles Laurence , Decher Gero , Felix Olivier , Lutz Jean‐François 
Published: August 2024

AbstractDigitally‐encoded poly(phosphodiesters) (d‐PPDE) with highly complex primary structures are evaluated for layer‐by‐layer (LbL) assembly. To be easily decoded by mass spectrometry (MS), these digital polymers contain many different monomers: 2 coding units allowing binary encryption, 1 cleavable spacer allowing controlled MS fragmentation, and 3 mass tags allowing fragment identification. These complex heteropolymers are therefore composed of 6 different motifs. Despite this strong sequence heterogeneity, it is found that they enable a highly controlled LbL film formation. For instance, a regular growth is observed when alternating the deposition of negatively‐charged d‐PPDE and positively‐charged poly(allyl amine hydrochloride) (PAH). Yet, in this approach, the interdistance between consecutive coded d‐PPDE layers remains relatively small, which may be an issue for data storage applications, especially for the selective decoding of the stored information. Using poly(sodium 4‐styrene sulfonate) (PSS) as an intermediate non‐coded polyanion, it is shown that a controlled interdistance between d‐PPDE layers can be easily achieved, while still maintaining a regular LbL growth. Last but not least, it is found in this work that d‐PPDE of relatively small molecular weight (i.e., significantly smaller than those of PAH and PSS) still enables a controlled LbL assembly.
Potential of Benchtop NMR for the Determination of Polymer Molar Masses, Molar Mass Distributions, and Chemical Composition Profiles by Means of Diffusion‐Ordered Spectroscopy, DOSY
Authors: Tratz Johanna , Gaborieau Marianne , Matz Markus , Pollard Michael , Wilhelm Manfred 
Published: August 2024

AbstractThe determination of molar masses and their distributions is crucial in polymer synthesis and design. This work presents the current performance and limitations of diffusion‐ordered spectroscopy (DOSY) on a low‐field (benchtop) NMR spectrometer (at 90 MHz) as an alternative to size exclusion chromatography (SEC) for determining diffusion coefficient distributions (DCDs) and molar mass distributions (MMDs). After optimization for narrowly distributed homopolymers, MMDs obtained with inverse Laplace transformation (ILT) and log‐normal distribution are compared with average molar masses obtained with mono‐ and bi‐exponential fits, as well as MMDs obtained from SEC. This approach enables ILT to determine DCDs and MMDs even for bimodal homopolymers with fully spectrally overlapping signals and block copolymers with various chemical compositions, for which chemical composition profiles are determined. The feasibility of low‐field diffusion NMR with samples dissolved in non‐deuterated solvents is further demonstrated and methods for solvent suppression are discussed.
Effect of SiC dominated with ZrB2 particles on the ablation and mechanical properties of carbon/novolac‐epoxy (EPN1180) composite at 3000°C
Authors: Kasmaei Mahdi Pour‐Jafari , Alaei Mohammad Hossein , Jam Jafar Eskandari , Soltani Seyed Ali Khalife 
Published: August 2024

AbstractThis study investigates the mechanical properties and erosion resistance of high temperature–pressure carbon‐epoxy novolac insulation reinforced with ZrB2/SiC particles. For this reason, at first, five samples were fabricated using the hot press, which included resin epoxy novolac EPN1180 base without reinforcement and four samples containing resin with 20:80, 30:70, 40:60, and 50:50 of SiC: ZrB2 particles respectively. After manufacturing of the samples, the mechanical properties were evaluated through bending and tensile testing, followed by erosion resistance properties by the use of oxyacetylene flame erosion tests. Chemical composition and surface morphology analysis of the composites were conducted using energy‐dispersive spectroscopy, scanning electron microscopy, and x‐ray diffraction analysis. Results indicate that the addition of ceramic particles enhances both mechanical properties and erosion resistance of the composite. The pure resin sample exhibited the highest weight loss and thickness reduction, while the sample containing 40% SiC and 60% ZrB2 demonstrated the least weight loss and thickness reduction about 55% and 83% respectively compared to pure sample. Additionally, the sample with 30% SiC and 70% ZrB2 had the lowest backside temperature. Furthermore, the sample with 20% SiC and 80% ZrB2 exhibited the highest mechanical properties, with a tensile strength of 422.5 MPa and flexural strength of 587.11 MPa. Morphological analysis revealed the presence of phases such as SiO2, ZrO2, and ZrSiO4 attributable to the ZrB2/SiC particles, contributing to the enhancement of erosion resistance.Highlights
Examines volume ratios of ZrB2/SiC.
Discovers the best particle ratio (20%SiC, 80%ZrB2) for mechanical properties.
Identifies the best particle ratio (30% SiC, 70% ZrB2) for erosion resistance.
Reveals key phases enhancing erosion resistance with advanced analysis methods.
Linear and mass ablation rate improved by 83% and 55% (best formation).
Monocentric Study on the Performance of Noninvasive Prenatal Testing on Cell‐Free DNA for the Detection of Monosomy X
Authors: Steinfort Kelly , Fransen Erik , Blaumeiser Bettina , Janssens Katrien 
Published: August 2024

ABSTRACTObjectiveIncreasing the PPV of monosomy X detected by the non‐invasive prenatal test (NIPT) by discriminating a (mosaic) monosomy X genotype of fetal versus maternal origin.MethodsOut of 30,700 women referred for NIPT between January 2014 and December 2021, 79 had a high risk result for 45,X. Discrimination between fetal and maternal 45,X was made based on the values for ffX, ffY and SeqFF. Follow‐up was provided through analysis of amniotic fluid, maternal blood, umbilical cord blood, neonatal blood and/or placental biopsies.ResultsFollow‐up data were available for 70/79 women; after exclusion of one twin pregnancy, 69 pregnancies were evaluated (87.3%). Forty one of those were correctly predicted as being maternal or fetal, for an overall PPV of 59.4% (95% confidence interval [CI] 47%–71%). Of the 33 predicted fetal cases with follow‐up, 11 were indeed of fetal origin, equating to a PPV of 33.3% (95% CI 18%–52%); three additional cases turned out to be placental in origin, six were maternal and for 13, no explanation could be found. The PPV of maternal cases was 88.2% (30/34 cases with follow‐up correctly predicted; 95% CI 73%–97%). One case turned out to be fetal; for the other three, follow‐up studies failed to prove the presence of monosomy X. Two cases for which no prediction on the origin of the monosomy X could be made (inconclusive high‐risk NIPT result) turned out to have confined placental mosaicism.ConclusionAlthough the PPV for fetal monosomy X remains lower than for the common trisomies, the total PPV for 45,X screening with NIPT can be improved by discerning fetal from (mosaic) maternal 45,X genotype. Thorough follow‐up to determine the origin of the aberrant NIPT result is advised, so that women can be adequately counseled on the risk in their current and future pregnancies and, in case of maternal mosaic monosomy X, of their own prospects.
[BMIM]Cl‐AgNPs Immobilized on Eggshell Membrane as an Adsorbent for Solid Phase Extraction of Sulfamethoxazole in Lake and Tap Water
Authors: Mhd Wahi Nur Azila , Fadzil Faris Darwish , Mohamad Sharifah , Mohd Jamil Arniza Khairani 
Published: August 2024

AbstractAn alternative solid phase extraction (SPE) material, 1‐butyl‐3‐methylimidazolium chloride–silver nanoparticles/eggshell membrane ([BMIM]Cl‐AgNPs/ESM), is developed by synthesizing [BMIM]Cl‐AgNPs using a simple reduction method and immobilizing directly on ESM. The newly developed material is successfully applied for extraction and detection of sulfamethoxazole (SMX) in environmental aqueous samples via a high‐performance liquid chromatography‐diode array detector (HPLC‐DAD). Characterization is accomplished by Fourier transform infrared (FTIR) and field emission scanning electron microscopy/energy dispersive X‐ray (FESEM/EDX), confirming the presence of [BMIM]Cl‐AgNPs on ESM. The optimization of [BMIM]Cl‐AgNPs/ESM‐based SPE method is studied by the one variable at a time (OVAT) approach. Method validation shows good linearity (R2 = 0.9995) in the range of 10–500 µg L−1, with the detection and quantification limits determined to be 3.07 and 9.31 µg L−1 respectively. Additionally, a reusability study shows the developed material can extract SMX up for three cycles without significant reduction in its efficiency. Excellent recoveries (90.07–104.08%) in spiked tap and lake water demonstrate the potential of [BMIM]Cl‐AgNPs/ESM for trace‐level detection of pollutants.
Analysis of thermal stability for slow burning propellant based on isothermal testing: Self‐accelerating decomposition temperature (SADT) calculation and validation
Authors: Luo Yi‐min , Xia Yu , Wang Jun‐hong , Ma Teng , Feng Zhang‐qi , Xu Sen , Wu Xing‐liang 
Published: August 2024

AbstractBurning rate suppressants (BRSs) refer to a series of additives that reduce the burning rate of propellants, crucial for achieving sustained and stable thrust. This research focuses on assessing the impact of ammonium sulfate and ammonium oxalate on thermal stability and their potential as BRSs. Due to the stronger inhibitory effect of ammonium sulfate on the AP proton transfer process, the activation energy of propellant's first decomposition can be increased from 94.71 kJ mol−1 to 129.69 kJ mol−1 at a 3 % addition level. Based on Semenov model, the self‐accelerated decomposition temperatures (TSADT) were calculated and validated through 7‐day isothermal test. Introducing ammonium sulfate and ammonium oxalate raised the TSADT from 197.31 °C to 220.90 °C and 215.06 °C, respectively, deviating less than 4 % from experimental results. Among the propellants tested, those with ammonium sulfate showed prolonged response delay times (44.43–33.60 h), lower superheating temperatures (222.8–445.5 °C), and reduced mass loss rates (33.0–71.4 %) after 7 days of isothermal storage at 220–240 °C. The consistency between thermal analysis and isothermal test underscores the significant impact of activation energy on thermal stability.
Preparation and characteristics of boron‐based composite micro‐units encapsulated by potassium perchlorate
Authors: Qin Yang , Liu Jie , Zeng Jiangbao , Zou Jinbin , Song Ye , Li Fengsheng 
Published: August 2024

AbstractTo improve the ignition and combustion performance of boron (B), the B@ potassium perchlorate (KP) composite micro‐units are successfully prepared by recrystallization of solvent evaporation. The morphology and structural composition show that B@KP composite micro‐units are formed by the gentle recrystallization of KP at the heterogeneous interface between B particles and solvents. It is shown by thermal analysis that the initial thermal decomposition temperature of KP is reduced by 49 °C due to the reduction of particle size. In addition, the heat of 420 J/g released by the thermal decomposition of KP is beneficial to the evaporation of the oxide boron (B2O3) film on the surface of B, which reduces the initial oxidation temperature of B by 185 °C and improves the ignition performance of B. Interestingly, the oxygen (O2) released by the thermal decomposition of KP quickly reacts with B to release heat of 3608 J/g, which improves the combustion performance of B. The optimal mass ratio of B to KP is 1: 5, which results in the ignition delay time of 641 ms, a reduction of 19 ms compared to the physical mixed sample. The ignition delay times of other samples are 724 ms, 680 ms and 650 ms respectively, and B could not be ignited successfully. In the combustion process, all samples emit a bright green flame of B combustion, and even a fierce combustion flame like a mushroom cloud appears. In a word, the B@KP composite micro‐units have great potential for application in solid propellants.
Asynchronous nonfragile guaranteed performance control for singular switched positive systems: An event‐triggered mechanism
Authors: Wang Jinling , Li Qiang , Li Shuo , Zhang Linzhong 
Published: August 2024

SummaryThis paper addresses the guaranteed performance control problem for a class of singular switched positive systems, where the switching signal is subject to a state‐dependent process. Firstly, the causality, regularity, positivity, and asymptotical stability of the considered systems are discussed. In order to prevent the occurrence of data collisions and reduce the consumption of communication resources, the event‐triggered (E‐T) mechanism is applied. This is one of the initial attempts to introduce the E‐T scheme for such special systems. Besides, an asynchronous nonfragile controller under the E‐T scheduling scheme is designed to make certain that the resulting closed‐loop systems are causal, regular, positive, asymptotically stable, and have a guaranteed performance value . Through the application of the co‐positive Lyapunov function method and the min‐projection strategy, the corresponding sufficient conditions are given in the form of linear programming (LP). Finally, the effectiveness of the controller proposed in this paper is verified via two simulation examples.
Aggregation‐Induced Emissive Feringa‐Type Motor: Toward the Dual‐Functional Motor in a Single Molecular Aggregation System
Authors: Jiang Ziwei , Qin Yunan , Liao Guohong , Liu Li , Luo Yanling , Li Quan , Guo Kun 
Published: August 2024

AbstractAggregation‐induced emission (AIE)allows tunable photoluminescence via the simple regulation of molecular aggregation. The research spurt along this vein has also offered tremendous opportunities for light‐responsive artificial molecular machines that are to be fully explored for performing versatile functions. Herein, the study reports a light‐driven Feringa‐type motor, when in the appropriate aggregation state, not only demonstrates the light‐activated rotary motion but emits photons with good quantum yield. A semi‐quantitative TD‐DFT calculation is also conducted to aid the understanding of the competitive photoluminescence and photoisomerization processes of the motor. Cytotoxicity test shows this motor possesses good biocompatibility, laying a solid foundation for applying it in the bio‐environment. The results demonstrated that the engagement of the aggregation‐induced emission concept and light‐driven Feringa‐motor can lead to the discovery of the novel motorized AIEgen, which will further stimulate the rise of more advanced molecular motors capable of executing multi‐functionalities.
Highly Anisotropic Thermally Conductive Dielectric Polymer/Boron Nitride Nanotube Composites for Directional Heat Dissipation
Authors: Zandieh Azadeh , Buahom Piyapong , Baradaran Shokouhi Elnaz , Mark Lun Howe , Rahmati Reza , Aghababaei Tafreshi Omid , Hamidinejad Mahdi , Mandelis Andreas , Kim Keun Su , Park Chul B. 
Published: August 2024

AbstractAn ideal dielectric material for microelectronic devices requires a combination of high anisotropic thermal conductivity and low dielectric constant (ɛ′) and loss (tan δ). Polymer composites of boron nitride nanotubes (BNNTs), which offer excellent thermal and dielectric properties, show promise for developing these dielectric polymer composites. Herein, a simple method for fabricating polymer/BNNT composites with high directional thermal conductivity and excellent dielectric properties is presented. The nanocomposites with directionally aligned BNNTs are fabricated through melt‐compounding and in situ fibrillation, followed by sintering the fibrous nanocomposites. The fabricated nanocomposites show a significant enhancement in thermal properties, with an in‐plane thermal conductivity (K‖) of 1.8 Wm−1K−1—a 450% increase—yielding a high anisotropy ratio (K‖/K⊥) of 36, a 1700% improvement over isotropic samples containing only 7.2 vol% BNNT. These samples exhibit a 120% faster in‐plane heat dissipation compared to the through‐plane within 2 s. Additionally, they display low ɛ′ of ≈3.2 and extremely low tan δ of ≈0.014 at 1 kHz. These results indicate that this method provides a new avenue for designing and creating polymer composites with enhanced directional heat dissipation properties along with high K‖, suitable for thermal management applications in electronic packaging, thermal interface materials, and passive cooling systems.
Intercepting Dendrite Growth With a Heterogeneous Solid Electrolyte for Long‐Life All‐Solid‐State Lithium Metal Batteries
Authors: Yu Tao , Liu Yuankai , Liu Yiwen , Li Haoyu , Ning Wenjie , Feng Yinhui , Zuo Daxian , Zhou Haoshen , Guo Shaohua 
Published: August 2024

AbstractThe application of lithium metal anode in all‐solid‐state batteries has the potential to achieve both high energy density and safety performance. However, the presence of serious dendrite issues hinders this potential. Here, the ion transport pathways and orientation of dendrite growth are regulated by utilizing the differences of ionic conductivity in heterogeneous electrolytes. The in situ formed Li–Ge alloy phases from the spontaneous reaction between Li10GeP2S12 and the attracted dendrites greatly enhance the ability to resist dendrite growth. As an outcome, the heterogeneous electrolyte achieves a high critical current density of 2.1 mA cm−2 and long‐term stable symmetrical battery operation (0.3 mA cm−2 for 17 000 h and 1.0 mA cm−2 for 2000 h). Besides, due to the superior interfacial stability and low interface impedance between the heterogeneous electrolyte and lithium anode, the Li||LiNi0.8Co0.1Mn0.1O2 full battery exhibits great cycling stability (80.5% after 500 cycles at 1.0 mA cm−2) and rate performance (125.4 mAh g at 2.0 mA cm−2). This work provides a unique strategy of interface regulation via heterogeneous electrolytes design, offering insights into the development of state‐of the‐art all‐solid‐state batteries.
POCUS use in the critical care areas: The use of posterior view for heart assessment
Authors: Cheong Issac , Merlo Pablo Martín , Tamagnone Francisco Marcelo 
Published: August 2024

AbstractEchocardiography can be quickly deployed for bedside management of critically ill patients, using parasternal, apical, and subxiphoid windows. However, lung air can obstruct these views. As left pleural effusion can cause pulmonary atelectasis, it creates a liquid space that improves ultrasonic transmission when using a postero‐lateral approach. This unconventional view uses a phased array transducer positioned at the posterior axillary line between the fourth and fifth intercostal spaces, enabling four‐chamber heart visualization. Although limited without pleural effusion, this method becomes valuable in the presence of a left‐sided effusion and when conventional views are inadequate.
Chemometrics‐Empowered Optimization of a Reliable Reversed Phase–High Performance Liquid Chromatography Method for the Simultaneous Estimation of Erythromycin and Adapalene in Pharmaceutical Nanoformulation
Authors: Shirkoli Nisha , Mastiholimath Vinayak 
Published: August 2024

ABSTRACTAn innovative, simple, economical, and sensitive reversed phase–high performance liquid chromatography (RP–HPLC) chromatographic method for simultaneous analysis of erythromycin (ERY) and adapalene (ADP) in bulk and pharmaceutical nanoformulation was developed by analytical quality‐by‐design (AQbD) avenue. According to published research, there is no strategy that integrates RP–HPLC with AQbD for estimating ERY and ADP. The analysis was carried out with Box–Behnken design, which reduced trial runs and design points. Acetonitrile: orthophosphoric acid (OPA) (0.1% triethanolamine) in pH 6.2 water was used as the mobile phase. The ratio was set to 35:65 (v/v) at 0.8 mL/min flow rate to detect the analytes at 231 nm. As per the guidelines in International Conference on Harmonization Q1A (R2), the developed approach was validated. ERY and ADP regression coefficients (r2) were found to be 0.9998 and 0.9999, respectively, over 5–25 µg/mL range. Validation parameters comprising linearity, sensitivity, system suitability, precision, robustness, and accuracy were performed. To assess stability, the drugs were subjected to stress conditions (hydrolytic, oxidative, thermal, and photolytic), and drugs were most vulnerable to degrade in alkaline and oxidative conditions. A new technique successfully analyzed novel drug carriers loaded with ERY and ADP.