bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ligand‐Enabled Nickel‐Catalyzed Redox‐Relay Migratory Hydroarylation of Alkenes with Arylborons
Authors: He Yuli , Liu Chuang , Yu Lei , Zhu Shaolin 
Published: March 2020

AbstractA redox‐relay migratory hydroarylation of isomeric mixtures of olefins with arylboronic acids catalyzed by nickel complexes bearing diamine ligands is described. A range of structurally diverse 1,1‐diarylalkanes, including those containing a 1,1‐diarylated quaternary carbon, were obtained in excellent yields and with high regioselectivity. Preliminary experimental evidence supports the proposed non‐dissociated chainwalking of aryl‐nickel(II)‐hydride species along the alkyl chain of alkenes before selective reductive elimination at a benzylic position. A catalyst loading as low as 0.5 mol % proved to be sufficient in large‐scale synthesis while retaining high reactivity, highlighting the practical value of this transformation.
Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
Authors: Chang Xin , Ma Pei‐Long , Chen Hong‐Chao , Li Chuan‐Ying , Wang Peng 
Published: March 2020

AbstractReported here is the development of a class of chiral spirosilabiindane scaffolds by Rh‐catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh‐catalyzed hydrogenation and a Pd‐catalyzed intramolecular carboamination.
Enzyme Mimetic Active Intermediates for Nitrate Reduction in Neutral Aqueous Media
Authors: Li Yamei , Go Yoo Kyung , Ooka Hideshi , He Daoping , Jin Fangming , Kim Sun Hee , Nakamura Ryuhei 
Published: March 2020

AbstractNitrate is a pervasive aquatic contaminant of global environmental concern. In nature, the most effective nitrate reduction reaction (NRR) is catalyzed by nitrate reductase enzymes at neutral pH, using a highly‐conserved Mo center ligated mainly by oxo and thiolate groups. Mo‐based NRR catalysts mostly function in organic solvents with a low water stability. Recently, an oxo‐containing molybdenum sulfide nanoparticle that serves as an NRR catalyst at neutral pH was first reported. Herein, in a nanoparticle‐catalyzed NRR system a pentavalent MoV(=O)S4 species, an enzyme mimetic, served as an active intermediate for the NRR. Potentiometric titration analysis revealed that a redox synergy among MoV−S, S radicals, and MoV(=O)S4 likely play a key role in stabilizing MoV(=O)S4, showing the importance of secondary interactions in facilitating NRR. The first identification and characterization of an oxo‐ and thiolate‐ligated Mo intermediates pave the way to the molecular design of efficient enzyme mimetic NRR catalysts in aqueous solution.
Two methods for terminal sliding‐mode synchronization of fractional‐order nonlinear chaotic systems
Authors: Mao Beixing 
Published: March 2020

AbstractThe self‐adaptive terminal sliding mode synchronization of fractional‐order nonlinear chaotic systems is investigated under uncertainty and external disturbance. A novel non‐singular terminal sliding surface is proposed and proved to be stable. Based on Lyapunov stability theory, a sliding mode control law is proposed to ensure the occurrence of sliding‐mode motion. In addition, two methods of the controller and the self‐adaptive rules are used to establish the sliding mode function, and two sufficient conditions for achieving self‐adaptive terminal sliding‐mode synchronization of fractional‐order uncertain nonlinear systems are identified. The results show that designing appropriate control law and sliding‐mode surface can achieve self‐adaptive terminal sliding mode synchronization of the fractional high‐order systems with uncertainty. The effectiveness and applicability of the sliding mode control technique are validated through numerical simulation.
Multiscalar Investigation of FeVO4 Conversion Cathode for a Low Concentration Zn(CF3SO3)2 Rechargeable Zn‐Ion Aqueous Battery
Authors: Kumar Sonal , Verma Vivek , Chua Rodney , Ren Hao , Kidkhunthod Pinit , Rojviriya Catleya , Sattayaporn Suchinda , de Groot Frank M. F. , Manalastas William , Srinivasan Madhavi 
Published: March 2020

AbstractBattery cathode materials operating on multivalent‐ion intercalation are prone to short operational lifetimes, traditionally explained to be due to poor solid‐state diffusion. Here, we overcome this problem by using a conversion‐type cathode material and demonstrate the benefits in a FeVO4 host structure. The rechargeable Zn‐ion battery exhibits stability for an unprecedented operational lifetime of 57 days with a high capacity of 272 mAh g−1 (60 mA g−1) over 140 cycles. We use a combination of synchrotron‐based XAS, SRXTM, Raman, XRD and HRTEM techniques to elucidate the cathode material evolution at multilength‐scale for understanding the Zn‐ion storage mechanism. We further highlight the benefits of using a low‐salt concentration electrolyte and pH‐consideration analysis in aqueous battery development, the optimization of which leads to a 4‐fold increase in battery performance as compared to conventional high‐salt concentration electrolyte formulations.
Skullcapflavone I has a potent anti‐pancreatic cancer activity by targeting miR‐23a
Authors: Cui Jing , Li Hao , Wang Ying , Tian Tian , Liu Chao , Wang Yanan , Sun Shukai , Feng Baisui 
Published: March 2020

AbstractBaicalein has been widely studied and showed a potent activity against pancreatic cancer in both in vivo and in vitro studies. Little is known regarding the effects of Skullcapflavone I (SFI), despite they have similar structures. So, this study was to explore the function of SFI on human pancreatic cancer. Panc‐1 cells were transfected with miR‐23a precursor, miR‐23a inhibitor or the negative controls, and subsequently treated by SFI. Cell viability, Bromodeoxyuridine (BrdU)‐positive cell rate, apoptosis, migration, invasion, and related protein expression were assessed by utilizing Cell Counting Kit‐8 (CCK‐8), BrdU staining, apoptosis assessment, transwell assay, and western blot. SFI significantly reduced the proliferation, migration, and invasion, as well as induced apoptosis of Panc‐1 cells. MiR‐23a, miR‐21, and miR‐155 were lowly expressed while miR‐145 and miR‐146a were highly expressed in SFI‐treated cell. Of note, the antitumor effects of SFI were promoted by miR‐23a suppression whereas attenuated by miR‐23a overexpression. JAK/STAT and MAPK pathways were inhibited by SFI. Also, the pathway inhibition in SFI‐treated cells was reversed by miR‐23a overexpression. SFI might be a promising anti‐pancreatic cancer agent by inhibiting cancer cells growth and motility. The anticancer activities of SFI might be through downregulation of miR‐23a, as well as inhibition of JAK/STAT and MAPK pathways.
Effects of pericardial tamponade on the hemodynamics of aortic stenosis
Authors: Kern Morton J. , Seto Arnold H. , Ng Angie T. , Yu Jeannie H. 
Published: March 2020

AbstractCompressive pericardial physiology (i.e., cardiac tamponade) reduces ventricular chamber volume/filling and cardiac output, which exacerbates coexisting hemodynamic derangements. In this hemodynamic rounds, we demonstrate the interaction of two hemodynamic conditions in one patient with acute pericardial tamponade in the setting of aortic stenosis (AS). Simultaneous pressures across the aortic valve before and after relief of cardiac tamponade demonstrate an acute and uncommon improvement in the hemodynamics of AS.
Intentional bioprosthetic tricuspid valve fracture to facilitate transcatheter valve‐in‐valve deployment
Authors: Karahalios Brian , Breinholt John P. , Little Stephen H. , Huie Lin C. 
Published: March 2020

AbstractWhile transcatheter valve‐in‐valve (ViV) implantation may reduce the number of lifetime surgical reinterventions in some patients with congenital heart disease, in other patients the bioprosthetic valve ring can lead to patient‐prosthesis mismatch due to reduction of internal diameter if a transcatheter valve is implanted. A 49‐year‐old woman with multiple prior cardiac surgeries presented with heart failure due to bioprosthetic tricuspid valve stenosis. Initial predilation valvuloplasty suggested conventional ViV implant would produce patient‐prosthesis mismatch, therefore, we intentionally fractured the bioprosthetic valve ring to facilitate optimal hemodynamics with implantation of a 29 mm transcatheter valve.
Association of left ventricular end‐diastolic pressure with mortality in patients undergoing percutaneous coronary intervention for acute coronary syndromes
Authors: Leistner David M. , Dietrich Steven , Erbay Aslihan , Steiner Julia , Abdelwahed Youssef , Siegrist Patrick T. , Schindler Matthias , Skurk Carsten , Haghikia Arash , Sinning David , Riedel Matthias , Landmesser Ulf , Stähli Barbara E. 
Published: March 2020

AbstractObjectivesThis study sought to investigate the relation between left ventricular end‐diastolic pressure (LVEDP) and outcomes in patients undergoing percutaneous coronary intervention (PCI) for acute coronary syndromes (ACS).BackgroundRisk stratification in ACS patients is important. Data on the role of LVEDP in the prognostication of ACS patients are scarce.MethodsA total of 1,410 patients undergoing PCI for ACS and with available data on LVEDP were divided according to LVEDP tertiles (lowest tertile: ≤13 mmHg, intermediate tertile: 14–20 mmHg, and highest tertile: >20 mmHg). The primary endpoint was all‐cause mortality at a median follow‐up of 246 [28–848] days.ResultsMedian LVEDP was 16 (11–22) mmHg. All‐cause mortality was 2.8%, 4.5%, and 15.0% in the lowest, the intermediate, and the highest LVEDP tertile groups (p < .001), respectively. Belonging to the highest LVEDP tertile was associated with an increased risk of all‐cause mortality (adjusted hazard ratio [HR] = 2.66, 95% confidence interval [CI] [1.30, 5.47], p = .008). By receiver operating characteristic curve analysis, the optimal cut‐off value for predicting all‐cause mortality was 20 mmHg (sensitivity 68.3%, specificity 72.5%). There was no differential effect of LVEDP on mortality in patients with and without LV dysfunction (interaction p = .23) or ST‐elevation myocardial infarction as index ACS event (interaction p = .86).ConclusionsIn patients undergoing PCI for ACS, LVEDP was independently related with mortality. Hence, LVEDP should be incorporated into early risk stratification and clinical decision making of ACS patients.
Heterogeneous colonic content: A prenatal sonographic manifestation of lysinuric protein intolerance
Authors: Dimitriou Christos , Saliba Souha , Peyrassol Xavier , Ben Abbou Wafa , Nassogne Marie Cécile , Neugroschl Carine , Wiame Elsa , De Leener Anne , Cassart Marie 
Published: March 2020

AbstractWe report a fetus with heterogeneous colonic content, an isolated sonographic prenatal sign of lysinuric protein intolerance, a very rare metabolic disease. Familial genetic enquiries confirmed heterozygote mutation in the implicated gene in parents. The prenatal diagnosis led to neonatal dietary adaptation and avoided acute complications.
Congenital intrahepatic portosystemic venous shunt embolization: A two‐case experience
Authors: Bayona Molano Maria del Pilar , Krauthamer Andres , Barrera Juan Carlos , Luna Cibele , Castillo Patricia , Swersky Adam , Bhatia Shivank 
Published: March 2020

AbstractCongenital intrahepatic portosystemic venous shunts are rare vascular malformations which are incidentally discovered on imaging or once hepatic encephalopathy becomes clinically apparent. Surgical ligation and endovascular embolization are potential treatments.
Defect Engineering of Two‐Dimensional Molybdenum Disulfide
Authors: Chen Xin , Denninger Peter , Stimpel‐Lindner Tanja , Spiecker Erdmann , Duesberg Georg S. , Backes Claudia , Knirsch Kathrin C. , Hirsch Andreas 
Published: March 2020

AbstractTwo‐dimensional (2D) molybdenum disulfide (MoS2) holds great promise in electronic and optoelectronic applications owing to its unique structure and intriguing properties. The intrinsic defects such as sulfur vacancies (SVs) of MoS2 nanosheets are found to be detrimental to the device efficiency. To mitigate this problem, functionalization of 2D MoS2 using thiols has emerged as one of the key strategies for engineering defects. Herein, we demonstrate an approach to controllably engineer the SVs of chemically exfoliated MoS2 nanosheets using a series of substituted thiophenols in solution. The degree of functionalization can be tuned by varying the electron‐withdrawing strength of substituents in thiophenols. We find that the intensity of 2LA(M) peak normalized to A1g peak strongly correlates to the degree of functionalization. Our results provide a spectroscopic indicator to monitor and quantify the defect engineering process. This method of MoS2 defect functionalization in solution also benefits the further exploration of defect‐free MoS2 for a wide range of applications.
Thermal Decomposition of Ternary Sodium Graphite Intercalation Compounds
Authors: Au Heather , Rubio Noelia , Buckley David J. , Mattevi Cecilia , Shaffer Milo S. P. 
Published: March 2020

AbstractGraphite intercalation compounds (GICs) are often used to produce exfoliated or functionalised graphene related materials (GRMs) in a specific solvent. This study explores the formation of the Na‐tetrahydrofuran (THF)‐GIC and a new ternary system based on dimethylacetamide (DMAc). Detailed comparisons of in situ temperature dependent XRD with TGA‐MS and Raman measurements reveal a series of dynamic transformations during heating. Surprisingly, the bulk of the intercalation compound is stable under ambient conditions, trapped between the graphene sheets. The heating process drives a reorganisation of the solvent and Na molecules, then an evaporation of the solvent; however, the solvent loss is arrested by restacking of the graphene layers, leading to trapped solvent bubbles. Eventually, the bubbles rupture, releasing the remaining solvent and creating expanded graphite. These trapped dopants may provide useful property enhancements, but also potentially confound measurements of grafting efficiency in liquid‐phase covalent functionalization experiments on 2D materials.
Photoredox‐Mediated Reaction of gem‐Diborylalkenes: Reactivity Toward Diverse 1,1‐Bisborylalkanes
Authors: Kumar Nivesh , Eghbarieh Nadim , Stein Tamar , Shames Alexander I. , Masarwa Ahmad 
Published: March 2020

AbstractThe use of gem‐diborylalkenes as radical‐reactive groups is explored for the first time. These reactions provide an efficient and general method for the photochemical conversion of gem‐diborylalkenes to rapidly access 1,1‐bisborylalkanes. This method exploits a novel photoredox decarboxylative radical addition to gem‐diborylalkenes to afford α‐gem‐diboryl carbon‐centered radicals, which benefit from additional stability by virtue of an interaction with the empty p‐orbitals on borons. The reaction offers a highly modular and regioselective approach to γ‐amino gem‐diborylalkanes. Furthermore, EPR spectroscopy and DFT calculations have provided insight into the radical mechanism underlying the photochemistry reaction and the stability of the bis‐metalated radicals, respectively.
Push–Pull (Iso)quinoline Chromophores: Synthesis, Photophysical Properties, and Use for White‐Light Emission
Authors: Ibrahim Mohamed Allaoui Zaina , le Gall Estelle , Fihey Arnaud , Plaza‐Pedroche Rodrigo , Katan Claudine , Robin‐le Guen Françoise , Rodríguez‐López Julián , Achelle Sylvain 
Published: March 2020

AbstractThe photophysical properties of a series of conjugated push–pull (iso)quinolines were studied. The compounds were synthesized by well‐established and straightforward methodologies. The materials exhibited not only emission solvatochromism in a variety of nonpolar solvents, but also tunable halochromism. Some of the compounds remained moderately luminescent after protonation and had a red emissive form, which was used to obtain white‐light emission, both in solution and in thin films, by controlled protonation of the initially blue–green‐emitting materials. This methodology has potential applications in the fabrication of white organic light‐emitting diodes with two forms of a single emitter in equilibrium.
The enduring legacy of Koji Nakanishi's research on natural products and bioorganic chemistry. Part 2. Inception and establishment of the ECD exciton chirality method in 1960s to 1970s: A marvel of Nakanishi's Japanese team
Authors: Harada Nobuyuki 
Published: March 2020

AbstractThe electronic circular dichroism (ECD) exciton chirality method is very useful for determining the absolute configuration (AC) of chiral compounds. In the ECD spectroscopy, the chromophore‐chromophore interaction, ie, exciton coupling, is very important. For example, Harada and Nakanishi first discovered in 1969 that chiral dibenzoates exhibit exciton split bisignate Cotton effects, from the sign of which the screw sense between two long axes of benzoate chromophores, ie, the AC of dibenzoate, can be determined. This method was named the dibenzoate chirality rule and has been successfully applied to various natural products to determine their ACs. During these studies, it was also found that this CD method was expanded to encompass other aromatic and olefin chromophores like naphthalene, diene, enone, etc. Therefore, the name of the dibenzaote chirality rule was changed to the CD exciton chirality method. In 1970s, there were heated controversies about the inconsistency between X‐ray Bijvoet and CD exciton chirality methods, which was a shocking and serious problem in the community of molecular chirality research. Harada and coworkers synthesized the most ideal cage compound with two anthracene chromophores to connect X‐ray Bijvoet and CD exciton chitality methods and proved that these two methods are consistent with each other.
Chiral separation of underivatized amino acids in supercritical fluid chromatography with chiral crown ether derived column
Authors: Miller Larry , Yue Lei 
Published: March 2020

AbstractThe supercritical fluid chromatographic separation of underivatized amino acids was explored using immobilized chiral crown ether column CROWNPAK CR‐I (+) and mass spectrometric detection. The type of modifier, acidic additives, and the role of water were investigated. Enantioseparation was achieved for all 18 amino acids investigated with short retention times (less than 3 minutes) and average resolution of greater than 5.0. Analysis of enantiomerically pure standards demonstrated the D enantiomer eluted first for all amino acids using a CROWNPAK CR‐I (+) column.
Preparation of mesoporous MCM‐41 supported zinc sorbents by microwave in‐situ oxidation for H2S removal in coal gas
Authors: Li Yang , Feng Yu , Wu Mengmeng , Guo Enhui , Li Qiaochun , Mi Jie 
Published: March 2020

AbstractZn‐based MCM‐41 supporter sorbents were prepared using the microwave in‐situ oxidation method. Other sorbents were heated using a conventional heating method to contrast the performance for H2S removal. The sorbents were tested at 500°C in fixed reactor and dried simulated Texaco coal gas was employed for the sulphurized atmosphere. The results show that sorbents prepared by microwave oxidation had a better toleration for the adsorption of H2S. A 13.2% improvement occurred in the sulphur capacity of the sorbents heated by the microwave method. XRD, SEM with EDS‐element mapping, TEM, N2 adsorption, and XPS were used to characterize the properties of the sorbents. Due to the selective heating of the microwave and the superiority of the in‐situ oxidation method, the sorbents heated by microwave exhibited more appropriate structures for sulphurization. Meanwhile, the even heating environment supplied by the microwave resulted in a more uniform distribution of the active component. The microwave also had an effect on the chemical bond and reduced the binding energy of the active component, which enhanced the reactivity between the H2S and the sorbents. The preferable features generated by microwave in‐situ oxidation accelerate the replacement of S to O, and therefore the Zn‐based MCM‐41 sorbents prepared by the microwave method have an increased capability for H2S removal in high temperature coal gas.
Post model‐fitting exploration via a “Next‐Door” analysis
Authors: Guan Leying , Tibshirani Robert 
Published: March 2020

AbstractWe propose a simple method for evaluating the model that has been chosen by an adaptive regression procedure, our main focus being the lasso. This procedure deletes each chosen predictor and refits the lasso to get a set of models that are “close” to the chosen “base model,” and compares the error rates of the base model with that of nearby models. If the deletion of a predictor leads to significant deterioration in the model's predictive power, the predictor is called indispensable; otherwise, the nearby model is called acceptable and can serve as a good alternative to the base model. This provides both an assessment of the predictive contribution of each variable and a set of alternative models that may be used in place of the chosen model. We call this procedure “Next‐Door analysis” since it examines models “next” to the base model. It can be applied to supervised learning problems with ℓ1 penalization and stepwise procedures. We have implemented it in the R language as a library to accompany the well‐known glmnet library. The Canadian Journal of Statistics 48: 447–470; 2020 © 2020 Statistical Society of Canada
Glue till you drop – Experiments on Historical Adhesives
Authors: Schälte Miriam , Lück Gisela 
Published: March 2020

AbstractBereits seit mehreren Jahrtausenden verwenden Menschen Klebstoffe. Anfangs dienten diese vor allem der Fabrikation einfacher Werkzeuge und Jagdwaffen, während sie heute in beinahe allen Industrie‐ und Lebensbereichen zu finden sind. Dieser Beitrag stellt Experimente zur Herstellung einiger der ältesten Klebstoffe vor: das Birkenpech, Klebemixturen aus Baumharz und einen Glutinleim. Diese sind für den Chemie‐ bzw. Sachunterricht, insbesondere aber auch für AGs und Projekttage geeignet, um intermolekulare Wechselwirkungen auf abwechslungsreiche Weise zu thematisieren. Vor der Vorstellung der Experimente werden die chemischen und physikalischen Grundlagen des Klebens sowie die historischen Hintergründe der drei thematisierten Klebstoffe erläutert.
The thermal reduction of graphene oxide – A simple and exciting manufacturing process of graphene
Authors: Schedy Andreas , Oetken Marco 
Published: March 2020

AbstractGraphen, die zweidimensionale Modifikation des Kohlenstoffs, steht aufgrund einer Vielzahl an herausragenden Eigenschaften derzeit im Fokus der Forschung. Die Synthese von Graphen verläuft im Labormaßstab über das Zwischenprodukt Graphenoxid. In diesem Beitrag wird mit der thermischen Reduktion ein Verfahren vorgestellt, mit dem Graphenoxid einfach, sicher und schnell zu Graphen reduziert werden kann. Die thermische Reduktion von Graphenoxid in einem geschlossenen System unter Sauerstoffausschluss erlaubt es zudem, die Reaktionsprodukte dieser Reduktion aufzufangen und zu analysieren.
Evaluating Sustainability in chemistry teaching
Authors: Zowada Christian , Linkwitz Michael , Siol Antje , Eilks Ingo 
Published: March 2020

AbstractGerade in der heutigen Zeit wird von verschiedensten Akteuren ein starker Wandel hin zur Nachhaltigkeit gefordert, wobei die Chemie durch grüne und nachhaltige Verfahrensweisen geprägt sein soll. Aber wann ist Chemie nachhaltig? Um dies zu reflektieren, entwickelt die Fachdisziplin selbst kontinuierlich entsprechende Instrumente der Nachhaltigkeitsbewertung für Chemikalien und Prozesse. Dieser Artikel gibt einen Überblick über aktuelle Entwicklungen und macht Vorschläge, wie solche Nachhaltigkeitsbewertungen Eingang in den Chemieunterricht in der Sekundarstufe finden können.