bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extrusion 3D Printing of Polymeric Materials with Advanced Properties
Authors: Jiang Zhen , Diggle Broden , Tan Ming Li , Viktorova Jekaterina , Bennett Christopher W , Connal Luke A. 
Published: August 2020

Abstract3D printing is a rapidly growing technology that has an enormous potential to impact a wide range of industries such as engineering, art, education, medicine, and aerospace. The flexibility in design provided by this technique offers many opportunities for manufacturing sophisticated 3D devices. The most widely utilized method is an extrusion‐based solid‐freeform fabrication approach, which is an extremely attractive additive manufacturing technology in both academic and industrial research communities. This method is versatile, with the ability to print a range of dimensions, multimaterial, and multifunctional 3D structures. It is also a very affordable technique in prototyping. However, the lack of variety in printable polymers with advanced material properties becomes the main bottleneck in further development of this technology. Herein, a comprehensive review is provided, focusing on material design strategies to achieve or enhance the 3D printability of a range of polymers including thermoplastics, thermosets, hydrogels, and other polymers by extrusion techniques. Moreover, diverse advanced properties exhibited by such printed polymers, such as mechanical strength, conductance, self‐healing, as well as other integrated properties are highlighted. Lastly, the stimuli responsiveness of the 3D printed polymeric materials including shape morphing, degradability, and color changing is also discussed.
Aerobic oxidation of benzyl alcohol in a slug flow microreactor: Influence of liquid film wetting on mass transfer
Authors: Hommes Arne , Disselhorst Bas , Yue Jun 
Published: August 2020

AbstractHomogeneous Co/Mn/Br catalyzed aerobic oxidation of benzyl alcohol in acetic acid to benzaldehyde was performed in polytetrafluoroethylene microreactors operated under slug flow at temperatures up to 150°C and pressures up to 5 bar. Depending on the bubble velocity and length, a wetted or dewetted slug flow was observed, characterized typically by a complete or partially wetting liquid film around the bubble body. The latter flow suffered from a limited interfacial area for mass transfer. Experiments at temperatures up to ca. 90°C were under kinetic control given no product yield difference under wetted and dewetted slug flows and were used to establish a simplified kinetic expression (first order in benzyl alcohol and zero order in oxygen). This allows to develop a mass transfer model combined with an instantaneous reaction regime that well described the experimental results at higher temperatures where mass transfer was limiting in the dewetted slug flow.
Sulfonyl PIM‐1: A diverse separation membrane with dilation resistance
Authors: Anstine Dylan M. , Mendez Nicholas F. , Colina Coray M. 
Published: August 2020

AbstractA sulfone modified variant (soPIM‐1) of the first polymer of intrinsic microporosity has been studied through molecular simulations to analyze its applicability for adsorption‐based separations of diverse nonpolar, quadrupolar, and dipolar adsorbate species. Single component gas phase adsorption isotherms of each adsorbate are provided. The adsorptive properties of soPIM‐1 are reported from the application of two methods: (a) traditional grand canonical Monte Carlo (GCMC) simulations and (b) a combination of Monte Carlo and molecular dynamics (GCMC/MD) techniques, which accounts for sorption‐induced polymer dynamics. The calculated isosteric heats of adsorption are compared to those from the parent PIM‐1 structure and reveals increased CO2 affinity with relatively no change in hydrocarbon affinity. Moreover, to quantify soPIM‐1's resistance to dilation the evolution of the microporous structure across the adsorption isotherm loading pressures has been evaluated. Relatedly, nonequilibrium MD simulations have been utilized to determine that soPIM‐1 is approximately twice as stiff as PIM‐1.
The Na⋅⋅⋅B Bond in NaBH3−: A Different Type of Bond
Authors: Foroutan‐Nejad Cina 
Published: August 2020

AbstractA newly introduced Na−B bond in NaBH3−has been a challenge for the chemical bonding community. Here, a series of MBH3−(M=Li, Na, K) species and NaB(CN)3−are studied within the context of quantum chemical topology approaches. The analyses suggest that M–B interaction cannot be classified as an ordinary covalent, dative, or even simple ionic interaction. The interactions are controlled by coulombic forces between the metals and the substituents on boron, for example, H or CN, more than the direct M–B interaction. On the other hand, while the characteristics of the (3, −1) critical points of the bonds are comparable to weak hydrogen bonds, not covalent bonds, the metal and boron share a substantial sum of electrons. To the best of the author's knowledge, the characteristics of these bonds are unprecedented among known molecules. Considering all paradoxical properties of these bonds, they are herein described as ionic‐enforced covalent bonds.
Preparation and characterization of imidazolyl ionic liquid‐based shear thickening dispersion system
Authors: Cao Chuanzhi , Luo Yan , Xiao Min 
Published: August 2020

AbstractShear thickening liquid (STF) is a new nonNewtonian fluid widely used in industrial production. In this paper, a novel shear thickening and dispersing system, namely poly methyl methacrylate (PMMA)/1‐butyl‐3‐methylimidazole hexa‐fluorophosphate ([BMIM]PF6), was prepared using ultrasonic with PMMA as the dispersing phase and [BMIM]PF6 as the dispersing medium. The stability, thixotropic, reversibility, rheology, and viscoelasticity of the dispersion system was studied, respectively. The dispersed system has good stability. The dispersed system shows high response sensitivity to shear rate, as well as good reversibility to shear thickening. Compared with traditional silicon dioxide/polyethylene glycol dispersion system, PMMA/[BMIM]PF6 dispersion system displays a significantly enhanced shear thickening effect. Nonionic surfactant triton X‐100 of 4 wt% can greatly improve PMMA/[BMIM]PF6 dispersion system's shear thickening behavior. This paper provides a new idea for the further development of protective materials by using STF.
Vapor deposition polymerization of synthetic rubber thin film in a plasma enhanced chemical vapor deposition reactor
Authors: Gürsoy Mehmet 
Published: August 2020

AbstractRubber is one of the most commonly used industrial materials worldwide. However, there is a gap in the literature on the production of rubber thin films in nanoscale. When the rubber thin films are produced in nanoscale, they can be used in high‐tech applications where bulk rubbers have never been used before. This study is one of the first investigations to focus on the vapor‐based production of the polyisoprene (PI), which is an important member of the synthetic rubber class. For this purpose, a single‐step, rapid and environmentally friendly method based on plasma enhanced chemical vapor deposition (PECVD) was employed to produce PI thin films using 2‐methyl‐1,3‐butadiene (isoprene). The high‐vapor pressure of isoprene makes it a promising monomer for the production of chemical vapor deposition polymers. The effect of plasma processing parameters on the PI deposition rate was investigated. The deposition rate of PI thin film as high as 40 nm/min was achieved and the contact angle of PI coated bamboo surface was found to be 146.8°. The mechanical durability and laundering tests of PI thin films were performed. Based on this study results, PI thin films produced by PECVD can be used in a number of potential applications.
Design, synthesis, and cytotoxicity screening of new synthesized imidazolidine‐2‐thiones as VEGFR‐2 enzyme inhibitors
Authors: Zaki Islam , Ramadan Heba M. M. , El‐Sayed El‐Sherbiny H. , Abd El‐Moneim Mohamed 
Published: August 2020

AbstractA series of imidazolin‐2‐thione derivatives was synthesized and structurally confirmed through the use of different spectroscopic techniques such as infrared, nuclear magnetic resonance, and mass spectrometry along with elemental analyses. The breast cancer cell line MCF‐7 was utilized in the evaluation of the cytotoxic activity of the prepared molecules. The tested molecules 3 and 7 exhibited the best results on MCF‐7 cells, with mean IC50 values of 3.26 and 4.31 µM, respectively. The results of the VEGFR‐2 assay indicated that compounds 3 and 7 displayed a good inhibition of the VEGFR‐2 kinase enzyme. Additionally, DNA flow cytometry of compounds 3 and 7 showed cell cycle arrest at the G0/G1 phase, cell apoptosis, and marked DNA fragmentation in MCF‐7 cells. Finally, compounds 3 and 7 were proved to upregulate the activation of effector caspase‐3/7, as presented by the caspase‐3/7 green flow cytometry assay.
The Fe4+/3+ Redox Mechanism in NaFeO2: A Simultaneous Operando Nuclear Resonance and X‐ray Scattering Study
Authors: Fehse Marcus , Bessas Dimitrios , Mahmoud Abdelfattah , Diatta Aliou , Hermann Raphael P. , Stievano Lorenzo , Sougrati Moulay Tahar 
Published: August 2020

AbstractSimultaneous operando Nuclear Forward Scattering and transmission X‐ray diffraction and 57Fe Mössbauer spectroscopy measurements were carried out in order to investigate the electrochemical mechanism of NaFeO2 vs. Na metal using a specifically designed in situ cell. The obtained data were analysed using an alternative and innovative data analysis approach based on chemometric tools such as Principal Component Analysis (PCA) and Multivariate Curve Resolution ‐ Alternating Least Squares (MCR‐ALS). This approach, which allows the unbiased extraction of all possible information from the operando data, enabled the stepwise reconstruction of the independent “real” components permitting the description of the desodiation mechanism of NaFeO2. This wealth of information allows a clear description of the electrochemical reaction at the redox‐active iron centres, and thus an improved comprehension of the cycling mechanisms of this material vs. sodium.
Bilateral middle cerebellar peduncle lesions: Neuroimaging features and differential diagnoses
Authors: Jiang Jiwei , Wang Jirui , Lin Meiqing , Wang Xiaoting , Zhao Jinli , Shang Xiuli 
Published: August 2020

AbstractObjectivesLesions limited to the bilateral middle cerebellar peduncles (MCPs) are uncommon. This retrospective study investigated diseases with a proclivity for the bilateral MCPs and explored the associations between their neuroimaging features and clinical findings for the differential diagnosis of such lesions.MethodsWe enrolled 26 patients who were admitted to our department between January 2016 and March 2019 with bilateral MCP abnormalities on magnetic resonance imaging (MRI). The demographic, clinical, and neuroimaging characteristics, and the biomarkers and diagnoses were evaluated.ResultsAlthough all patients exhibited symmetrical bilateral MCP hypointensities on T1‐weighted imaging and hyperintensities on T2‐weighted and fluid‐attenuated inversion recovery imaging, they were diagnosed with different conditions. Diagnoses included acute cerebral infarction (ACI) (n = 9, 34.62%), Wallerian degeneration (WD) (n = 8, 30.77%), multiple system atrophy (MSA) (n = 6, 23.08%), neuromyelitis optica (NMO) (n = 1, 3.85%), heroin‐induced leukoencephalopathy (n = 1, 3.85%), and primary central nervous system lymphoma (PCNSL) (n = 1, 3.85%). Patients with ACI exhibited bilateral MCP‐restricted diffusion hyperintensities on diffusion‐weighted imaging and corresponding stenosis or occlusion of the vertebrobasilar system. The initial MRI of patients with WD depicted pontine infarctions, while symmetrical MCP lesions were observed on follow‐up MRI. Symmetrical MCP lesions, cruciform hyperintensity, and marked atrophy in the posterior fossa were characteristic manifestations of MSA. Longitudinally extensive myelitis affecting more than three vertebral segments on cervical MRI and positive serum AQP4‐IgG may be indicative of NMO. Heroin‐induced leukoencephalopathy was characterized by extra‐symmetrical lesions in the posterior limbs of the internal capsules, while the anterior limbs were spared. PCNSL was indicated by a significant and characteristic “fist” sign on contrast‐enhanced MRI.ConclusionsBilateral MCP lesions were most frequently observed in cerebrovascular diseases, followed by neurodegenerative diseases, inflammatory diseases, toxic encephalopathies, and lymphomas. Our findings demonstrate that bilateral MCP signal abnormalities are more common in patients with ACI and WD, with fewer degenerative processes than previously believed. The high frequency of WD may be attributed to the specific awareness of this pathology. WD can also present with stage‐related restricted diffusion and should not be mistaken for a new infarction. The symmetrical bilateral MCP hypointensities on T1‐weighted imaging and hyperintensities on T2‐weighted imaging often raise concern regarding a demyelinating process. Our findings emphasize that neurologists should consider the aforementioned conditions and correlate the specific neuroimaging characteristics and medical history before arriving at the final diagnosis.
Critical success factors for a circular economy: Implications for business strategy and the environment
Authors: Moktadir Md. Abdul , Kumar Anil , Ali Syed Mithun , Paul Sanjoy Kumar , Sultana Razia , Rezaei Jafar 
Published: August 2020

AbstractEco‐efficiency and resource optimization for business strategy and the environment can be achieved by the circular economy (CE) practices in supply chains (SCs). The leather industry is a significant industrial contributor to the economic growth of some countries, but at the same time, it leads to tremendous environmental pollution. This research focuses on the identification and evaluation of critical success factors (CSFs) needed in the business strategy development of CE practices as well as to minimize environmental pollution in leather industry SCs. The CSFs are identified via a comprehensive literature review and are validated by experts' opinions. The validated CSFs are further analyzed using the best–worst method (BWM) and the decision‐making trial and evaluation laboratory (DEMATEL). The BWM is used to identify the weights of the CSFs, and DEMATEL is used to determine the cause–effect relationship between the CSFs. The findings show that “leadership and top management commitment” is the most important CSF. Six CSFs are classified as causal towards CE practices: “leadership and top management commitment,” “strong legislation towards CE practices,” “ecological scarcity of resources,” “knowledge of CE practices,” “funding support for R&D from the government,” and “competitor pressure on CE practices.” The findings of this study can help managers in the leather industry implement CE practices in their existing SCs to minimize waste.
Coronary artery dissection following radiofrequency ablation for atrial fibrillation: Case report and review of the literature
Authors: Reddy S Ashwin , V. Khialani Bharat , Kyranis Stephen , P. Hoole Stephen 
Published: August 2020

AbstractCoronary artery injury following catheter ablation for cardiac arrhythmias is very rare. We present a case of left circumflex (LCx) coronary artery dissection causing inferoposterior ST‐elevation myocardial infarction following radiofrequency (RF) ablation for atrial fibrillation (AF) in a 39‐year‐old male with no cardiovascular risk factors. This was confirmed on coronary angiography and intracoronary vascular ultrasound (IVUS). The likely etiology is thermal injury during RF ablation for AF, due to the close proximity of the left atrial appendage and left pulmonary veins to the LCx. He was successfully treated with primary percutaneous coronary intervention with good outcome. This is, to our knowledge, the first reported case of proven acute coronary dissection secondary to RF ablation for AF reported in the literature, and highlights the importance of considering this as a mechanism for coronary occlusion in these patients.
COVID‐19 pneumonia with back pain: Presentation of an acute pulmonary embolism associated with novel coronavirus infection in an outpatient setting
Authors: Davis Kenyani 
Published: August 2020

AbstractThe Chinese Center for Disease Control and Prevention reported 80% of coronavirus infections were mild cases; hence, most cases will be managed in an outpatient setting. COVID‐19 is associated with a hypercoagulable state; therefore, further research should be done on outpatient use of anticoagulation for VTE/PE prophylaxis in these patients.
Hierarchy Concepts in Design and Synthesis of Nanocatalysts
Authors: Zeng Hua Chun 
Published: August 2020

AbstractHigh‐performance catalytic nanomaterials (nanocatalysts) are normally more complex than their phase‐pure counterparts in terms of preparation processes and physicochemical properties. Therefore, more thoughtful considerations are required on various hierarchy‐related issues in their design and synthesis, especially when deciding their composition, mass, activity, selectivity, reactivity, stability, surface, texture, porosity, structure, size, shape, density, and even cost for a system under development. In this Concept article, we will address some general considerations and approaches with respect to the design and synthesis of nanocatalysts. In particular, architectural conceivability, materials selection, synthetic technique and integration strategy will be discussed. Furthermore, we will use the development of integrated nanocatalysts as examples to highlight some key hierarchical issues and snapshot a few representative practices. Finally, a number of suggestions regarding future research directions are also proposed on the basis of personal perspective.
MOF‐derived/zeolite hybrid catalyst for the production of light olefins from CO2
Authors: Martín Nuria , Portillo Ander , Ateka Ainara , Cirujano Francisco G. , Oar‐Arteta Lide , Aguayo Andrés T. , Dusselier Michiel 
Published: August 2020

AbstractIn this contribution we propose an alternative catalytic system based on MOF derivatives and small pore zeolites for the selective conversion of CO2 into light olefins, using the lowest metal loadings and highest GHSV reported in literature. The catalyst synthesis involves deriving In−Zr oxides from MOFs containing these metals in their structure, i. e. (Zr)UiO‐67‐bipy‐In, via direct calcination in the presence of the zeolite, avoiding co‐precipitation, washing and mixing steps. This effectively creates a truly bifunctional In−Zr zeolite catalyst, opposed to physical mixtures of two catalysts using different precursors. The good dispersion and low loadings of the MOF‐derived In−Zr oxide supplemented with the strong acidity of chabazite‐type zeolites allows to couple the activation of CO2 with C−C coupling, obtaining space time yields of 0.1 mol of CO2 converted to light olefins per gram of In per hour at 375 °C, under the GHSV conditions employed.
Direct Introduction of an Alkylsulfonamido Group on C‐sites of Isomeric Dicarba‐closo‐dodecaboranes: The Influence of Stereochemistry on Inhibitory Activity against the Cancer‐Associated Carbonic Anhydrase IX Isoenzyme
Authors: Nekvinda Jan , Kugler Michael , Holub Josef , El Anwar Suzan , Brynda Jiří , Pospíšilová Klára , Růžičková Zdeňka , Řezáčová Pavlína , Grüner Bohumír 
Published: August 2020

AbstractCarbonic anhydrase IX (CA IX), a tumor‐associated metalloenzyme, represents a validated target for cancer therapy and diagnostics. Herein, we report the inhibition properties of isomeric families of sulfonamidopropyl‐dicarba‐closo‐dodecaboranes group(s) prepared using a new direct five‐step synthesis from the corresponding parent cages. The protocol offers a reliable solution for synthesis of singly and doubly substituted dicarba‐closo‐dodecaboranes with a different geometric position of carbon atoms. The closo‐compounds from the ortho‐ and meta‐series were then degraded to corresponding 11‐vertex dicarba‐nido‐undecaborate(1−) anions. All compounds show in vitro enzymatic activity against CA IX in the low nanomolar or subnanomolar range. This is accompanied by clear isomer dependence of the inhibition constant (Ki) and selectivity towards CA IX. Decreasing trends in Ki and selectivity index (SI) values are observed with increasing separation of the cage carbon atoms. Interactions of compounds with the active sites of CA IX were explored with X‐ray crystallography, and eight high‐resolution crystal structures uncovered the structural basis of inhibition potency and selectivity.
Unraveling the Mechanism of the IrIII‐Catalyzed Regiospecific Synthesis of α‐Chlorocarbonyl Compounds from Allylic Alcohols
Authors: Li Man , Sanz‐Marco Amparo , Martinez‐Erro Samuel , García‐Vázquez Víctor , Mai Binh Khanh , Fernández‐Gallardo Jacob , Himo Fahmi , Martín‐Matute Belén 
Published: August 2020

AbstractWe have used experimental studies and DFT calculations to investigate the IrIII‐catalyzed isomerization of allylic alcohols into carbonyl compounds, and the regiospecific isomerization–chlorination of allylic alcohols into α‐chlorinated carbonyl compounds. The mechanism involves a hydride elimination followed by a migratory insertion step that may take place at Cβ but also at Cα with a small energy‐barrier difference of 1.8 kcal mol−1. After a protonation step, calculations show that the final tautomerization can take place both at the Ir center and outside the catalytic cycle. For the isomerization–chlorination reaction, calculations show that the chlorination step takes place outside the cycle with an energy barrier much lower than that for the tautomerization to yield the saturated ketone. All the energies in the proposed mechanism are plausible, and the cycle accounts for the experimental observations.
Multifunctional chiral aminophosphines for enantiodivergent catalysis in a palladium‐catalyzed allylic alkylation reaction
Authors: Eliseenko Sviatoslav S. , Bhadbhade Mohan , Liu Fei 
Published: August 2020

AbstractTrifunctional MAP‐based chiral phosphines were tested as new ligands in a Pd‐catalyzed asymmetric allylic alkylation, demonstrating fast and enantiodivergent catalysis. The palladium complexes of representative ligands by X‐ray analysis revealed a novel mode of P,N‐coordination of the ligand to the palladium center, which may contribute to switching the sense of the asymmetric induction via combined steric and tunable H‐bonding interactions between the metal complex and the substrates.
Spirulina platensis‐capped mesoporous magnetic nanoparticles for the adsorptive removal of chromium
Authors: Mohan Sreelakshmi , Govindankutty Gopika , Sathish Asha , Kamaraj Nithya 
Published: August 2020

AbstractThe magnetic nanoparticles prepared through the co‐precipitation method were surface modified usingSpirulina platensis. The mesoporous and superparamagnetic nature of the adsorbent was confirmed by Brunauer‐Emmett‐Teller (BET) and vibrating sample magnetometer (VSM) analyses, respectively. Further, an increased specific surface area of 75.3 m2/g was reported in the BET studies. Parameters such as pH, contact time, concentration, and temperature were studied to optimize the operating conditions influencing adsorption. Thermodynamic studies justified the spontaneity and endothermic nature of adsorption. The adsorbent exhibited a better performance at 1.5 pH and 120 minutes of contact time. The monolayer adsorption capacity of the material was found to be 29.23 mg/g from the evaluation of Langmuir adsorption isotherm. The second‐ order kinetic studies suggest the predominance of chemisorption. Further, the X‐ray photoelectron spectroscopy (XPS) studies confirmed that the adsorption mechanism is electrostatic attraction accompanied by reduction. Notably, a regeneration efficiency of 75.26% was achieved with NaOH as the desorbing agent.