bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous Visualization of Wet Cells and Nanostructured Biomaterials in SEM using Ionic Liquids
Authors: Lee Bryan E. J. , DiCecco Liza‐Anastasia , Exir Hourieh , Weck Arnaud , Sask Kyla N. , Grandfield Kathryn 
Published: September 2020

AbstractThis work presents a successful methodology to image mammalian cells adhered to nanostructured titanium by using scanning electron microscopy (SEM) operating in low‐vacuum mode following ionic liquid treatment. Human osteoblast‐like Saos‐2 cells were treated with a room‐temperature ionic liquid, 1‐ethyl‐3‐methylimidazolium tetrafluoroborate, and subsequently imaged on titanium by SEM. Titanium substrates were modified to create laser‐induced periodic surface structures (LIPSS) for visualization at the submicron scale. By using a combination of fluorescence‐based cell metabolism along with light microscopy and SEM image analysis, the shape and location of irradiated cells were confirmed to be unchanged after multiple irradiation sessions; the viability of minimally irradiated cells was also unaltered. The wet imaging conditions combined with a rapid facile protocol using ionic liquid allows this technique to fulfill a niche in examining cellular behavior on biomaterials with submicron surface features. The demonstrated method to track observed cell adhesion to submicron surface features by SEM has great implications for understanding cell migration on nanostructured surfaces as well as the exploration of simpler SEM preparation methods for cellular imaging.
Activation of Protease and Luciferase Using Engineered Nostoc punctiforme PCC73102 DnaE Intein with Altered Split Position
Authors: Kawase Misaki , Fujioka Meiko , Takahashi Tsuyoshi 
Published: September 2020

AbstractInteins, self‐catalytic enzymes, have been widely used in the field of protein engineering and chemical biology. Here, Nostoc punctiforme PCC73102 (Npu) DnaE intein was engineered to have an altered split position. An 11‐residue N‐intein of DnaE in which Gly and Asp were substituted for Tyr4 and Glu5, respectively, was designed, and the active C‐intein variants were acquired by a GFP fluorescence‐based screening. The designed N‐intein and the obtained active C‐intein variants were used to construct a turn‐on system for enzyme activities such as human immunodeficiency 1 protease and NanoLuc luciferase. Based on the NanoLuc‐intein fusion, we developed two intein pairs, each of which is capable of reacting preferentially, by interchanging the charged amino acids on N‐ and C‐inteins. The specific splicing reactions were easily monitored and discriminated by bioluminescence resonance energy transfer (BRET).
Transcaval access for the emergency delivery of 5.0 liters per minute mechanical circulatory support in cardiogenic shock
Authors: Afana Majed , Altawil Mahmoud , Basir Mir , Alqarqaz Mohammad , Alaswad Khaldoon , Eng Marvin , O'Neill William W. , Lederman Robert J. , Greenbaum Adam B. 
Published: September 2020

AbstractObjectivesThe purpose of this study was to describe the feasibility and early outcomes of transcaval access for delivery of emergency mechanical circulatory support (MCS) in cardiogenic shock.BackgroundVascular access for implantation of MCS in patients with cardiogenic shock is often challenging due to peripheral arterial disease and vasoconstriction. Transcaval delivery of MCS may be an alternative. We describe a series of patients we implanted an Impella 5.0 device, on‐table without CT planning, through a percutaneous transcaval access route.MethodsTen patients with progressive or refractory cardiogenic shock underwent Impella 5.0 implantation via transcaval access. Demographic, clinical and procedural variables and in‐hospital outcomes were collected.ResultsAll ten underwent emergency implantation of the 7 mm diameter Impella 5.0 device via transcaval access. Six were women, with median age of 55.5 years (range, 29–69). Cardiogenic shock was attributed to idiopathic nonischemic cardiomyopathy (n = 4), myocarditis (n = 2), ischemic cardiomyopathy (n = 2), heart transplant rejection (n = 1), and unknown etiology (n = 1). Median duration of support was 92.1 hr (range, 21.2–165.4). Seven (70%) survived to device explant, with six (60%) surviving to access port closure and discharge. Among survivors, five recovered heart function and one received destination therapy left ventricular assist device.ConclusionsTranscaval access is feasible for emergency nonsurgical implantation of the Impella 5.0 device in cardiogenic shock with small or diseased iliofemoral arteries. This allows early institution of higher‐flow MCS than conventional femoral artery implantation of the 3.5 L Impella CP device, and enables a bridge‐to‐recovery or bridge‐to‐destination strategy.
Regioselective Isomerization of Terminal Alkenes Catalyzed by a PC(sp3)Pincer Complex with a Hemilabile Pendant Arm
Authors: De‐Botton Sophie , Filippov D.Sc. Oleg A. , Shubina Elena S. , Belkova Natalia V. , Gelman Dmitri 
Published: September 2020

AbstractWe describe an efficient protocol for the regioselective isomerization of terminal alkenes employing a previously described bifunctional Ir‐based PC(sp3)complex (4) possessing a hemilabile sidearm. The isomerization, catalyzed by 4, results in a one‐step shift of the double bond in good to excellent selectivity, and good yield. Our mechanistic studies revealed that the reaction is driven by the stepwise migratory insertion of Ir−H species into the terminal double bond/β‐H elimination events. However, the selectivity of the reaction is controlled by dissociation of the hemilabile sidearm, which acts as a selector, favoring less sterically hindered substrates such as terminal alkenes; importantly, it prevents recombination and further isomerization of the internal ones.
Evaluation of temperature compensation methods for a near‐infrared calibration to predict the viscosity of micellar liquids
Authors: Haroon Kiran , Arafeh Ali , Rodgers Thomas , Mendoza Ćesar , Baker Michael , Martin Philip 
Published: September 2020

AbstractNear‐infrared (NIR) spectroscopy is a popular technique for the measurement of chemical and physical properties in‐line using predictive models. The success of these models in industrial settings, in terms of accuracy and precision, often relies on the removal or avoidance of non‐linear spectral changes associated with fluctuating process parameters like temperature. In this work, a NIR calibration model developed to predict the viscosity of micellar liquids in‐line is used to evaluate various methods designed to account for temperature fluctuations. The viscosity of these liquids can vary on average by ±0.5 Pa s with a 1° change in temperature. The methods trialled include global linear techniques, a multivariate filter (generalised least squares weighting [GLSW]) and direct standardisation. The performances of these techniques were compared against one another based on root mean square error of prediction (RMSEP), prediction bias and rank. The best method was found to be GLSW, which was the least complex (five latent variables) and showed the lowest RMSEP (0.429 Pa s). This study provides insight into the use of recognised methods to remove temperature‐induced spectral variation in a PLS model developed to predict viscosity, where both NIR spectra and the property of viscosity itself are sensitive to temperature.
Programmable DNA Nanoflowers for Biosensing, Bioimaging, and Therapeutics
Authors: Lv Jigang , Dong Yuhang , Gu Zi , Yang Dayong 
Published: September 2020

AbstractDNA nanostructures have shown excellent prospects in biomedical applications owing to their unique sequence programmability, function designability, and biocompatibility. As a type of unique DNA–inorganic hybrid nanostructures, DNA nanoflowers (DNFs) have attracted considerable attention in the past few years. Precise design of the DNA sequence enables the functions of DNFs to be customized. Specifically, DNFs exhibit high physiological stability and more diverse properties by virtue of the incorporation of inorganic materials, which in turn have been applied in an assortment of biomedical fields. In this review, the design, synthesis, and biomedical applications of programmable DNFs are discussed. First, the background of DNA‐based materials and the fundamentals of DNFs are briefly introduced. In the second part, two synthetic methods of DNFs are categorized as the rolling circle amplification and salt aging method, focusing on the formation mechanism of DNFs and differences between the synthetic methods. In the third part, the biomedical applications of DNFs functional materials are summarized, including biosensing, bioimaging, and therapeutics. Finally, the challenges and future opportunities of DNFs are discussed toward more widespread applications.
Structure–Property Relationships in Bithiophenes with Hydrogen‐Bonded Substituents
Authors: Özen Bilal , Fadaei Tirani Farzaneh , Schenk Kurt , Lin Kun‐Han , Scopelliti Rosario , Corminboeuf Clémence , Frauenrath Holger 
Published: September 2020

AbstractThe use of crystal engineering to control the supramolecular arrangement of π‐conjugated molecules in the solid‐state is of considerable interest for the development of novel organic electronic materials. In this study, we investigated the effect of combining of two types of supramolecular interaction with different geometric requirements, amide hydrogen bonding and π‐interactions, on the π‐overlap between calamitic π‐conjugated cores. To this end, we prepared two series of bithiophene diesters and diamides with methylene, ethylene, or propylene spacers between the bithiophene core and the functional groups in their terminal substituents. The hydrogen‐bonded bithiophene diamides showed significantly denser packing of the bithiophene cores than the diesters and other known α,ω‐disubstituted bithiophenes. The bithiophene packing density reach a maximum in the bithiophene diamide with an ethylene spacer, which had the smallest longitudinal bithiophene displacement and infinite 1D arrays of electronically conjugated, parallel, and almost linear N−H⋅⋅⋅O=C hydrogen bonds. The synergistic hydrogen bonding and π‐interactions were attributed to the favorable conformation mechanics of the ethylene spacer and resulted in H‐type spectroscopic aggregates in solid‐state absorption spectroscopy. These results demonstrate that the optoelectronic properties of π‐conjugated materials in the solid‐state may be tailored systematically by side‐chain engineering, and hence that this approach has significant potential for the design of organic and polymer semiconductors.
Cycling between Molybdenum‐Dinitrogen and ‐Nitride Complexes to Support the Reaction Pathway for Catalytic Formation of Ammonia from Dinitrogen
Authors: Arashiba Kazuya , Tanaka Hiromasa , Yoshizawa Kazunari , Nishibayashi Yoshiaki 
Published: September 2020

AbstractInvited for the featured front cover of Kazuya Arashiba, Hiromasa Tanaka, Kazunari Yoshizawa, and Yoshiaki Nishibayashi at The University of Tokyo, Daido University, and Kyushu University. The image depicts a roulette wheel to represent the cycling reaction used in this work. Read the full text of the article at 10.1002/chem.202002200.
Breslow Intermediates (Amino Enols) and Their Keto Tautomers: First Gas‐Phase Characterization by IR Ion Spectroscopy
Authors: Paul Mathias , Peckelsen Katrin , Thomulka Thomas , Martens Jonathan , Berden Giel , Oomens Jos , Neudörfl Jörg‐M. , Breugst Martin , Meijer Anthony J. H. M. , Schäfer Mathias , Berkessel Albrecht 
Published: September 2020

AbstractBreslow intermediates (BIs) are the crucial nucleophilic amino enol intermediates formed from electrophilic aldehydes in the course of N‐heterocyclic carbene (NHC)‐catalyzed umpolung reactions. Both in organocatalytic and enzymatic umpolung, the question whether the Breslow intermediate exists as the nucleophilic enol or in the form of its electrophilic keto tautomer is of utmost importance for its reactivity and function. Herein, the preparation of charge‐tagged Breslow intermediates/keto tautomers derived from three different types of NHCs (imidazolidin‐2‐ylidenes, 1,2,4‐triazolin‐5‐ylidenes, thiazolin‐2‐ylidenes) and aldehydes is reported. An ammonium charge tag is introduced through the aldehyde unit or the NHC. ESI‐MS IR ion spectroscopy allowed the unambiguous conclusion that in the gas phase, the imidazolidin‐2‐ylidene‐derived BI indeed exists as a diamino enol, while both 1,2,4‐triazolin‐5‐ylidenes and thiazolin‐2‐ylidenes give the keto tautomer. This result coincides with the tautomeric states observed for the BIs in solution (NMR) and in the crystalline state (XRD), and is in line with our earlier calculations on the energetics of BI keto–enol equilibria.
Pitch‐Based Laminated Carbon Formed by Pressure Driving at Low Temperature as High‐Capacity Anodes for Lithium Energy Storage Systems
Authors: Yang Tao , Song Yan , Tian Xiaodong , Song Huaihe , Liu Zhanjun 
Published: September 2020

AbstractPitch has been used to prepare electrodes by high‐temperature heat treatments for supercapacitors, lithium‐ion batteries, on account of its rich aromatic ring structure. Here, the toluene‐soluble component of pitch is used to prepare a kind of laminated carbon. This was realized by a template‐free synthesis at low temperature with the addition of pressure. The toluene‐soluble component has a small molecular weight, which makes the thermal deformation ability stronger and then enhances the orientation of the carbon layer with the help of pressure. The prepared anode exhibits a splendid electrochemical performance compared with the traditional graphite anode. A high stable capacity of approximately 550 mAh g−1 at 50 mA g−1, which is much higher than graphite (372 mAh g−1), is obtained. Also, when the current density is up to 2 A g−1, the capacity is about 150 mAh g−1. Surprisingly, it also delivers a superior cycling performance. And when used as the anode/cathode electrode for lithium‐ion capacitors, a high energy density can be obtained. The present work offers an opportunity to utilize the pitch source in lithium energy storage with promising cycle life, high energy/power density, and low cost.
Intermolecular C−H Activation at the Allylic/Benzylic and Homoallylic/Homobenzylic Positions of Cyclic Hydrocarbons by a Stable Divalent Silicon Species
Authors: Koike Taichi , Kosai Tomoyuki , Iwamoto Takeaki 
Published: September 2020

AbstractDirect activation of inert C(sp3)−H bonds by main group element species is yet a formidable challenge. Herein, the dehydrogenation of cyclohexene and 1,2,3,4‐tetrahydronaphthalene through the allylic/benzylic and homoallylic/homobenzylic C−H bond activation by cyclic (alkyl)(amino)silylene 1 in neat conditions is reported to yield the corresponding aromatic compounds. As for the reaction of cyclohexene, allylsilane 3 and 7‐silanorbornene 4 were also observed, which could be interpreted as a direct dehydrogenative silylation reaction of monoalkenes at the allylic positions. Experimental and computational studies suggest that the dehydrogenation of cyclohexene at the homoallylic position was accomplished by a combination of silylene 1 and radical intermediates such as hydrosilyl radical INT1 or cyclohexenyl radical H, which are generated in the initial step of the reaction.
Rh‐Catalyzed Decarbonylative Cross‐Coupling between o‐Carboranes and Twisted Amides: A Regioselective, Additive‐Free, and Concise Late‐Stage Carboranylation
Authors: Li Chun‐Xiao , Ning Qian , Zhao Wenxuan , Cao Hou‐Ji , Wang Yi‐Ping , Yan Hong , Lu Chang‐Sheng , Liang Yong 
Published: September 2020

AbstractThe convenient cross‐coupling of sp2 or sp3 carbons with a specific boron vertex on carborane cage represents significant synthetic values and insurmountable challenges. In this work, we report an Rh‐catalyzed reaction between o‐carborane and N‐acyl‐glutarimides to construct various Bcage−C bonds. Under the optimized condition, the removable imine directing group (DG) leads to B(3)− or B(3,6)−C couplings, while the pyridyl DG leads to B(3,5)−Ar coupling. In particular, an unexpected rearrangement of amide reagent is observed in pyridyl directed B(4)−C(sp3) formation. This scalable protocol has many advantages, including easy access, the use of cheap and widely available coupling agents, no requirement of an external ligand, base or oxidant, high efficiency, and a broad substrate scope. Leveraging the RhI dimer and twisted amides, this method enables straightforward access to diversely substituted and therapeutically important carborane derivatives at boron site, and provides a highly valuable vista for carborane‐based drug screening.
Molybdenum‐Catalyzed Deoxygenation Coupling of Lignin‐Derived Alcohols for Functionalized Bibenzyl Chemicals
Authors: Jiang Huifang , Lu Rui , Luo Xiaolin , Si Xiaoqin , Xu Jie , Lu Fang 
Published: September 2020

AbstractWith the growing demand for sustainability and reducing CO2 footprint, lignocellulosic biomass has attracted much attention as a renewable, carbon‐neutral and low‐cost feedstock for the production of chemicals and fuels. To realize efficient utilization of biomass resource, it is essential to selectively alter the high degree of oxygen functionality of biomass‐derivates. Herein, we introduced a novel procedure to transform renewable lignin‐derived alcohols to various functionalized bibenzyl chemicals. This strategy relied on a short deoxygenation coupling pathway with economical molybdenum catalyst. A well‐designed H‐donor experiment was performed to investigate the mechanism of this Mo‐catalyzed process. It was proven that benzyl carbon‐radical was the most possible intermediate to form the bibenzyl products. It was also discovered that the para methoxy and phenolic hydroxyl groups could stabilize the corresponding radical intermediates and then facilitate to selectively obtain bibenzyl products. Our research provides a promising application to produce functionalized aromatics from biomass‐derived materials.
Metal–Organic Framework (MOF)‐Derived Electron‐Transfer Enhanced Homogeneous PdO‐Rich Co3O4 as a Highly Efficient Bifunctional Catalyst for Sodium Borohydride Hydrolysis and 4‐Nitrophenol Reduction
Authors: Dou Shasha , Zhou Shuqing , Huang Hexiu , Yan Puxuan , Shoko Elvis , Isimjan Tayirjan Taylor , Yang Xiulin 
Published: September 2020

AbstractDeveloping a bifunctional catalyst with low cost and high catalytic performance in NaBH4 hydrolysis for H2 generation and selective reduction of nitroaromatics will make a significant impact in the field of sustainable energy and water purification. Herein, a low‐loading homogeneously dispersed Pd oxide‐rich Co3O4 polyhedral catalyst (PdO‐Co3O4) with concave structure is reported by using a metal–organic framework (MOF)‐templated synthesis method. The results show that the PdO‐Co3O4 catalyst has an exceptional turnover frequency (3325.6 molH2 min−1 molPd−1), low activation energy (43.2 kJ mol−1), and reasonable reusability in catalytic H2 generation from NaBH4 hydrolysis. Moreover, the optimized catalyst also shows excellent catalytic performance in the NaBH4 selective reduction of 4‐nitrophenol to 4‐aminiphenol with a high first‐order reaction rate of approximately 1.31 min−1. These excellent catalytic properties are mainly ascribed to the porous concave structure, monodispersed Pd oxide, as well as the unique synergy between PdO and Co3O4 species, which result in a large specific surface area, high conductivity, and fast solute transport and gas emissions.
Non‐Planar Structures of Sterically Overcrowded Trialkylamines
Authors: Banert Klaus , Heck Manuel , Ihle Andreas , Shoker Tharallah , Wörle Michael , Boese A. Daniel 
Published: September 2020

AbstractSeveral amines with three bulky alkyl groups at the nitrogen atom, which exceed the steric crowding of triisopropylamine significantly, were synthesized, mainly by treating N‐chlorodialkylamines with Grignard reagents. In six cases, namely tert‐butyldiisopropylamine, 1‐adamantyl‐tert‐butylisopropylamine, di‐1‐adamantylamines with an additional N‐cyclohexyl or N‐exo‐2‐norbonyl substituent, as well as 2,2,6,6‐tetramethylpiperidine derivatives with N‐cyclohexyl or N‐neopentyl groups, appropriate single crystals were generated that enabled X‐ray diffraction studies and analysis of the molecular structures. The four noncyclic amines adopt triskele‐like conformations, and the sum of the three C−N−C angles is always in the range of 351.1° to 352.4°. Consequently, these amines proved to be structurally significantly flatter than trialkylamines without steric congestion, which is also signalized by the smaller heights of the NC3 pyramids (0.241–0.259 Å). There is no clear correlation between the heights of these pyramids and the degree of the steric crowding in the new amines, presumably because steric repulsion is partly compensated by dispersion interaction. In the cases of the two heterocyclic amines, the steric stress is smaller, and the molecular structures include quite different conformations. Quantum chemical calculations led to precise gas‐phase structures of the sterically overcrowded trialkylamines exhibiting heights of the NC3 pyramids and preferred molecular conformers which are similar to those resulting from the X‐ray studies.
An Unprecedented Bird Nest Molybdenum(V) Cobalto‐Phosphate Nanosized Wheel Constructed from the [H55(Mo24O48)(Co4O)2Co16(PO4)42(py)6(EtOH)2(H2O)11]3− Anion
Authors: Kang Run‐Kun , Dong Ya‐Yu , Cao Jia‐Peng , Luo Xi‐Ming , Du Ze‐Yu , Zhu Dunru , Xu Yan 
Published: September 2020

AbstractAn unprecedented bird‐nest high‐nuclear molybdenum(V) cobalto‐phosphate nanosized wheel modified by imidazole (im) and pyridine (py), {[H55(Mo24O48)(Co4O)2Co16(PO4)42(py)6(EtOH)2(H2O)11]‐ @[(Him)2(Hpy)]}(N‐Et‐py)(H2PO4)(py)7(EtOH)⋅12 H2O (1), has been successfully synthesized by self‐assembly. The anionic huge wheel consists of two rare {Co4O} squares, four {Co4} tetramers, four {Mo4} tetramers and four {Mo2} dimers, linked by bridging oxygen atoms and [PO4] groups and encloses two imidazolium cations and a protonated pyridium for charge balance. Surprisingly, 1 represents the first twisted wheel‐shaped cluster with a record high‐nuclear molybdenum(V) cobalto‐phosphate. The delocalized electron effects of the cluster are enhanced with the help of coordinated py ligands, which endows 1 with an excellent third‐order nonlinear optical (NLO) response. Additionally, 1 also shows a better photocatalytic water oxidation activity than Co(NO3)2 with the O2 production of 205 μmol during 6 h in the absence of the [Ru(bpy)3]2+ photosensitizer.
Gold Metallodrugs to Target Coronavirus Proteins: Inhibitory Effects on the Spike‐ACE2 Interaction and on PLpro Protease Activity by Auranofin and Gold Organometallics**
Authors: Gil‐Moles Maria , Basu Uttara , Büssing Rolf , Hoffmeister Henrik , Türck Sebastian , Varchmin Agnieszka , Ott Ingo 
Published: September 2020

AbstractGold complexes have a long tradition in medicine and for many examples antirheumatic, anticancer or anti‐infective effects have been confirmed. Herein, we evaluated the lead compound Auranofin and five selected gold organometallics as inhibitors of two relevant drug targets of severe acute respiratory syndrome coronaviruses (SARS‐CoV). The gold metallodrugs were effective inhibitors of the interaction of the SARS‐CoV‐2 spike protein with the angiotensin converting enzyme 2 (ACE2) host receptor and might thus interfere with the viral entry process. The gold metallodrugs were also efficient inhibitors of the papain‐like protease (PLpro) of SARS‐CoV‐1 and SARS‐CoV‐2, which is a key enzyme in the viral replication. Regarding PLpro from SARS‐CoV‐2, the here reported inhibitors are among the very first experimentally confirmed examples with activity against this target enzyme. Importantly, the activity of the complexes against both PLpro enzymes correlated with the ability of the inhibitors to remove zinc ions from the labile zinc center of the enzyme. Taken together, the results of this pilot study suggest further evaluation of gold complexes as SARS‐CoV antiviral drugs.