bluuebunny/crossref_metadata_2025 huggingface dataset:
Zur Promotion katalytischer Reaktionen durch akustische Oberflächenwellen
Authors: von Boehn Bernhard , Foerster Michael , von Boehn Moritz , Prat Jordi , Macià Ferran , Casals Blai , Khaliq Muhammad Waqas , Hernández‐Mínguez Alberto , Aballe Lucia , Imbihl Ronald
Published: July 2020

Akustische Oberflächenwellen (engl. Surface Acoustic Waves, SAWs) ermöglichen die Manipulation von Oberflächen mit potenziellen Anwendungen in der Katalyse, der Sensorik und der Nanotechnologie. Es wurde gezeigt, dass SAWs bei vielen Oxidations‐ und Zersetzungsreaktionen an metallischen und oxidischen Katalysatoren deren Aktivität und Selektivität erhöhen. Der Reaktionsmechanismus konnte jedoch bis heute nicht eindeutig geklärt werden. Mit Hilfe der stroboskopischen Röntgen‐Photoelektronenspektroskopie konnten wir eine Änderung der Austrittsarbeit im Sub‐Nanosekundenbereich während der Ausbreitung von 500 MHz‐SAW auf einer 9 nm dicken Platinschicht nachweisen. Wir bestimmen die Austrittsarbeitsänderung auf 455 μeV. Eine so geringe Variation schließt aus, dass elektronische Effekte durch elastische Verformung (Dehnung) eine große Rolle bei der SAW‐induzierten Promotion von katalytischen Reaktionen spielen. Ausserdem wurde gezeigt, dass die SAW‐induzierte Vermischung einer fünf Monolagen dicken Rh‐Schicht mit dem polykristallinen Platinsubstrat auf eine erhöhte thermische Diffusion zurückzuführen ist, die durch eine Erwärmung der Oberfläche um etwa 75 K bei der Anregung von SAW verursacht wird. Wir schlagen reversible strukturelle Veränderungen der Oberfläche als eine Hauptursache für die katalytische Promotion durch SAW vor.
Synthesis and Photocatalytic Properties of Titanium‐Porphyrinic Aerogels
Authors: Keum Yesub , Kim Bongkyeom , Byun Asong , Park Jinhee
Published: July 2020

We present novel titanium‐porphyrinic gels (TPGs) and titanium‐porphyrinic aerogels (TPAs), in which porphyrinic ligand tetrakis(4‐carboxyphenyl)porphyrin is coordinated to Ti‐oxo clusters. These hierarchically porous TPAs, with micro‐, meso‐, and macropores and reactant‐concentration‐dependent Brunauer‐Emmett‐Teller surface areas of 407–738 m2 g−1, are prepared by CO2 critical point drying of TPGs. Although the Ti4+ → Ti3+ photoreduction of TPAs is less efficient than that of crystalline microporous Ti‐porphyrinic framework DGIST‐1, prompt diffusion of O2 and spin‐trapping agents into the TPA pores causes the rapid generation of reactive oxygen species (ROS), as observed by EPR spectroscopy. When used as an ROS scavenger, large 1,3‐diphenylisobenzofuran is degraded by the best‐performing TPA 10 times faster than by DGIST‐1, suggesting that the accessibility of molecules (reactants) to pores (reactive centers) strongly influences photocatalytic activity.
A Series of Mesoporous Metal‐Organic Frameworks with Tunable Windows Sizes and Exceptionally High Ethane over Ethylene Adsorption Selectivity
Authors: Lysova Anna A. , Samsonenko Denis G. , Kovalenko Konstantin A. , Nizovtsev Anton S. , Dybtsev Danil N. , Fedin Vladimir P.
Published: July 2020

The NIIC‐20 (NIIC stands for Nikolaev Institute of Inorganic Chemistry) is a family of five isostructural metal‐organic frameworks (MOFs) based on dodecanuclear wheel‐shaped carboxylate building blocks {Zn12(RCOO)12(glycol)6} (glycol is deprotonated diatomic alcohol: ethylene glycol, 1,2‐propanediol, 1,2‐butanediol, 1,2‐pentanediol or glycerol), quantitatively crystallized from readily available starting chemicals. The crystal structures contain large mesoporous cages of 25 Å connected through {Zn12} rings, of which inner diameter and chemical nature depend solely on the chosen glycol. The NIIC‐20 compounds feature high surface area and rarely observed inversed adsorption affinity for saturated hydrocarbon (ethane) over the unsaturated ones (ethylene, acetylene). The corresponding IAST (Ideal Adsorbed Solution Theory) adsorption selectivity factors reach as much as 15.4 for C2H6/C2H4 and 10.9 for C2H6/C2H2 gas mixtures at ambient conditions, exceeding those for any other porous MOF reported so far. The remarkable combination of high adsorption uptakes and high adsorption selectivities makes the NIIC‐20 series a new benchmark of porous materials designed for ethylene separation applications.
Asymmetric Coupling of Carbon‐Centered Radicals Adjacent to Nitrogen: Copper‐Catalyzed Cyanation and Etherification of Enamides
Authors: Zhang Guoyu , Zhou Song , Fu Liang , Chen Pinhong , Li Yibiao , Zou Jianping , Liu Guosheng
Published: July 2020

The first copper‐catalyzed asymmetric cyanation and etherification reactions of enamides have been established, where a carbon‐centered radical adjacent to a nitrogen atom (CRAN) is enantioselectively trapped by a chiral copper(II) species. Moreover, the asymmetric cyanation of vinyl esters was disclosed as well. These reactions feature very mild reaction conditions and high functional group tolerance, and give a series of chiral α‐cyano amides, α‐cyano esters and α‐hemiaminals in good yields with excellent enantioselectivity. The chiral α‐cyano amides can be easily converted into enantioenriched 1,2‐diamines and amino acids.
Molecular Insights into Small‐Molecule Drug Discovery for SARS‐CoV‐2
Authors: Su Hailei , Zhou Feng , Huang Ziru , Ma Xiaohua , Natarajan Kathiresan , Zhang Minchuan , Huang Yong , Su Haibin
Published: July 2020

The mainstream approach to antiviral drugs against COVID‐19 is to focus on key stages of the SARS‐CoV‐2 life cycle. The vast majority of candidates under investigation are repurposed from agents of other indications. Understanding protein–inhibitor interactions at the molecular scale will provide crucial insights for drug discovery to stop this pandemic. In this article, we summarize and analyze the most recent structural data on several viral targets in the presence of promising inhibitors for COVID‐19 in the context of the perspective of modes of action (MOA) to unravel insightful mechanistic features with atomistic resolution. The targets include spike glycoprotein and various host proteases mediating the entry of the virus into the cells, viral chymotrypsin‐ and papain‐like proteases, and RNA‐dependent RNA polymerase. The main purpose of this review is to present detailed MOA analysis to inspire fresh ideas for both de novo drug design and optimization of known scaffolds to combat COVID‐19.
Hetero‐Diels–Alder Cycloaddition with RAFT Polymers as Bioconjugation Platform
Authors: Beloqui Ana , Mane Shivshankar R. , Langer Marcel , Glassner Mathias , Bauer Dennis M. , Fruk Ljiljana , Barner‐Kowollik Christopher , Delaittre Guillaume
Published: July 2020

We introduce the bioconjugation of polymers synthesized by RAFT polymerization, bearing no specific functional end group, by means of hetero‐Diels–Alder cycloaddition through their inherent terminal thiocarbonylthio moiety with a diene‐modified model protein. Quantitative conjugation occurs over the course of a few hours, at ambient temperature and neutral pH, and in the absence of any catalyst. Our technology platform affords thermoresponsive bioconjugates, whose aggregation is solely controlled by the polymer chains.
Electrochemical Stability of the Reconstructed Fe3O4(001) Surface
Authors: Grumelli Doris , Wiegmann Tim , Barja Sara , Reikowski Finn , Maroun Fouad , Allongue Philippe , Balajka Jan , Parkinson Gareth S. , Diebold Ulrike , Kern Klaus , Magnussen Olaf M.
Published: July 2020

Establishing the atomic‐scale structure of metal‐oxide surfaces during electrochemical reactions is a key step to modeling this important class of electrocatalysts. Here, we demonstrate that the characteristic (√2×√2)R45° surface reconstruction formed on (001)‐oriented magnetite single crystals is maintained after immersion in 0.1 M NaOH at 0.20 V vs. Ag/AgCl and we investigate its dependence on the electrode potential. We follow the evolution of the surface using in situ and operando surface X‐ray diffraction from the onset of hydrogen evolution, to potentials deep in the oxygen evolution reaction (OER) regime. The reconstruction remains stable for hours between −0.20 and 0.60 V and, surprisingly, is still present at anodic current densities of up to 10 mA cm−2 and strongly affects the OER kinetics. We attribute this to a stabilization of the Fe3O4 bulk by the reconstructed surface. At more negative potentials, a gradual and largely irreversible lifting of the reconstruction is observed due to the onset of oxide reduction.
Synthesis of Acyclic Aliphatic Amides with Contiguous Stereogenic Centers via Palladium‐Catalyzed Enantio‐, Chemo‐ and Diastereoselective Methylene C(sp3)−H arylation
Authors: Han Ye‐Qiang , Yang Xu , Kong Ke‐Xin , Deng Yao‐Ting , Wu Le‐Song , Ding Yi , Shi Bing‐Feng
Published: July 2020

The enantioselective desymmetrizing C−H activation of α‐gem‐dialkyl acyclic amides remains challenging because the availability of four chemically identical unbiased methylene C(sp3)−H bonds and increased rotational freedoms of the acyclic systems add tremendous difficulties for chemo‐ and stereocontrol. We have developed a method for the synthesis of acyclic aliphatic amides with α,β‐contiguous stereogenic centers via PdII‐catalyzed asymmetric arylation of unbiased methylene C(sp3)−H, in good yields and with high levels of enantio‐, chemo‐ and diastereoselectivity (up to >99 %eeand >20:1 d.r.). Successive application of this method enables the sequential arylation of thegem‐dialkyl groups with two different aryl iodides, giving a range of β‐Ar1‐β′‐Ar2‐aliphatic acyclic amides containing three contiguous stereogenic centers with excellent diastereoselectivity.
A meta‐Selective C−H Alumination of Mono‐Substituted Benzene by Using An Alkyl‐Substituted Al Anion through Hydride‐Eliminating SNAr Reaction
Authors: Kurumada Satoshi , Sugita Kengo , Nakano Ryo , Yamashita Makoto
Published: July 2020

Reaction of an Al‐centered anion with toluene proceeded to form C−H cleaved product with a perfect meta‐selectivity and a relatively small kinetic isotope effect (KIE, kH/kD=1.51). DFT calculations suggested a two‐step reaction mechanism and electronically controlled meta‐selectivity arising from the electron‐donating methyl group. The reaction with other mono‐substituted arenes was also investigated.
Reactivity and Lability Modulated by a Valence Electron Moving in and out of 25‐Atom Gold Nanoclusters
Authors: Li Guangjun , Hu Weigang , Sun Yongnan , Xu Jiayu , Cai Xiao , Cheng Xinglian , Zhang Yuying , Tang Ancheng , Liu Xu , Chen Mingyang , Ding Weiping , Zhu Yan
Published: July 2020

The emergence of atomically precise metal nanoclusters with unique electronic structures provides access to currently inaccessible catalytic challenges at the single‐electron level. We investigate the catalytic behavior of gold Au25(SR)18 nanoclusters by monitoring an incoming and outgoing free valence electron of Au 6s1. Distinct performances are revealed: Au25(SR)18− is generated upon donation of an electron to neutral Au25(SR)180 and this is associated with a loss in reactivity, whereas Au25(SR)18+ is generated from dislodgment of an electron from neutral Au25(SR)180 with a loss in stability. The reactivity diversity of the three Au25(SR)18 clusters stems from different affinities with reactants and the extent of intramolecular charge migration during the reactions, which are closely associated with the valence occupancies of the clusters varied by one electron. The stability difference in the three clusters is attributed to their different equilibria, which are established between the AuSR dissociation and polymerization influenced by one electron.
Intramolecular C(sp3)–H Bond Oxygenation by Transition‐Metal Acylnitrenoids
Authors: Tan Yuqi , Chen Shuming , Zhou Zijun , Hong Yubiao , Ivlev Sergei , Houk K. N. , Meggers Eric
Published: July 2020

This study demonstrates for the first time that easily accessible transition‐metal acylnitrenoids can be used for controlled direct C(sp3)‐H oxygenations. Specifically, a ruthenium catalyst activates N‐benzoyloxycarbamates as nitrene precursors towards regioselective intramolecular C−H oxygenations to provide cyclic carbonates, hydroxylated carbamates, or 1,2‐diols. The method can be applied to the chemoselective C−H oxygenation of benzylic, allylic, and propargylic C(sp3)−H bonds. The reaction can be performed in an enantioselective fashion and switched in a catalyst‐controlled fashion between C−H oxygenation and C−H amination. This work provides a new reaction mode for the regiocontrolled and stereocontrolled conversion of C(sp3)‐H into C(sp3)−O bonds.
An organoantimony nitrate complex with azastibocine framework as water tolerant Lewis acid catalyst for the synthesis of 1,2‐disubstitued benzimidazoles
Authors: Zhou Cong , Lei Jian , Liu Yongping , Au Chak‐Tong , Chen Yi , Yin Shuang‐Feng
Published: July 2020

A novel organoantimony complex of 6‐cyclohexyl‐6,7‐dihydrodibenzo[c,f] [1,5]azastibocin‐12(5H)‐yl nitrate (2) was synthesized and systematically characterized by techniques such as NMR spectra, TG‐DSC, and X‐ray diffraction. It was found that the complex 2 exhibits relatively strong Lewis acidity (3.3 < Ho ≤ 4.8) and could be employed as a water tolerant Lewis acid catalyst for the synthesis of synthetically valuable benzimidazole derivatives starting from aldehydes and arylenediamines. This catalytic system shows excellent tolerance toward a wide variety of functional groups, such as methyl, methoxyl, fluoro, chloro, bromo, nitro, cyan, trifluoromethyl, 1‐naphthaldehyde, furfural and n‐butyl, together with facile reusability in 5 times scale enlarged synthesis.
Recent Progress in the Synthesis of Homogeneous Erythropoietin (EPO) Glycoforms
Authors: Wang Yuxin , Yang Sung H. , Brimble Margaret A. , Harris Paul W. R.
Published: July 2020

Erythropoietin (EPO) has been regarded as a therapeutic glycoprotein for the clinical treatment of anaemia since its approval by the Food and Drug Administration (FDA) in 1989. Commercial production of the 165‐residue glycoprotein is by recombinant protein expression using mammalian cell lines that renders a complex mixture of glycoforms that have an identical amino acid sequence but variations in the structures of the pendant glycans. This heterogeneous nature of human recombinant EPO restricts structural and bioactivity studies in medicinal chemistry. Consequently, chemical synthesis provides an elegant approach for the preparation of complex homogeneous glycoproteins from a readily accessible pool of amino acids and sugars. In addition, the combination of chemical and biosynthesis enables robust and large‐scale production of homogeneous EPO. The scope of this minireview is to summarise the recent advances in the chemical and semisyntheses of homogeneous EPO glycoforms, highlighting the versatile approaches to the preparation and structural manipulations of the carbohydrate chains incorporated into synthetic EPO glycoproteins.
Impact of stent designs of second‐generation drug‐eluting stents on long‐term outcomes in coronary bifurcation lesions
Authors: Jang Woo Jin , Chun Woo Jung , Park Ik Hyun , Choi Ki Hong , Song Young Bin , Koo Bon‐Kwon , Doh Joon‐Hyung , Hong Soon‐Jun , Nam Chang‐Wook , Gwon Hyeon‐Cheol
Published: July 2020

Objectives

We compared the long‐term clinical outcomes of four different types of second‐generation drug‐eluting stents (DESs) in coronary bifurcation lesions.

Background

Clinical outcomes of different designs of second‐generation DESs are not well known in bifurcation lesions.

Methods

Patients who underwent percutaneous coronary intervention with second‐generation DESs for coronary bifurcation lesion were enrolled from 21 centers in South Korea. A total of 2,526 patients was evaluated and divided into four treatment groups according to DES type: bioabsorbable polymer biolimus‐eluting stent (BP‐BES group, n = 514), platinum chromium everolimus‐eluting stent (PtCr‐EES group, n = 473), cobalt nickel zotarolimus‐eluting stent (CoNi‐ZES group, n = 736), or cobalt chromium everolimus‐eluting stent (CoCr‐EES group, n = 803). Primary outcome was target lesion failure (TLF, defined as a composite of cardiac death, target vessel myocardial infarction, or target lesion revascularization). Inverse probability of treatment weighting (IPTW) was performed to reduce selection bias and potential confounding factors.

Results

For 5 years of follow‐up, the rates of TLF among the four DES groups were not significantly different (6.2% for BP‐BES group, 8.2% for PtCr‐EES group, 6.5% for CoNi‐ZES group, and 8.6% for CoCr‐EES group, p = .434). The results were consistent after IPTW adjustment (6.8, 8.4, 6.0, and 7.5%, respectively, p = .554). In subgroup analysis, the similarity of long‐term outcomes among the four different types of second‐generation DES was consistent across subgroups regardless of side branch treatment (p for interaction = .691).

Conclusion

There seems to be no significant difference in long‐term clinical outcomes among patients who received different types of second‐generation DES for coronary bifurcation lesion.
Iron‐catalyzed hydrosilylation of diacids in the presence of amines: a new route to cyclic amines
Authors: Wei Duo , Netkaew Chakkrit , Wu Jiajun , Darcel Christophe
Published: July 2020

Cyclic amines (such as pyrrolidines, piperidines and azepanes) are present in a large class of natural products and bioactive molecules. Herein, we present a novel chemoselective strategy for building N‐substituted cyclic amines via iron catalyzed one‐pot hydrosilylation starting from readily available dicarboxylic acids and amines, with hydrosilanes as the hydride sources. The described methodology allows the preparation of a wide range of N‐alkylated and arylated cyclic amine derivatives (including pharmaceuticals Fenpiprane and Prozapine) in moderate to excellent yields, starting from inexpensive succinic, glutaric, and adipic acids with dimethyl carbonate as a green solvent.
Synthesis of Polycaprolactone Nanoparticles through Flow‐Focusing Microfluidic‐Assisted Nanoprecipitation
Authors: Heshmatnezhad Fazlollah , Nazar Ali Reza Solaimany
Published: July 2020

Polycaprolactone nanoparticles (PCL NPs) were produced by a liquid nonsolvent nanoprecipitation process in a flow‐focusing microfluidic device and optimized in terms of particle size, polydispersity index (PDI), and zeta potential ζ. The effects of flow rate ratio (FRR), total flow rate (TFR), the organic solvents tetrahydrofuran and dimethylformamide (DMF), the surfactants polyvinyl alcohol and Tween 80, and polymer molecular weight on the size, PDI, and ζ of PCL NPs were investigated. A stability study was performed to compare the effect of the surfactants on the characteristics of PCL NPs over 7 d. The smallest particles are produced at the highest FRR, TFR, and polymer molecular weight and lowest polymer concentration in DMF. The presence of both surfactants results in smaller NPs.
Role of Coordination Number and Geometry in Controlling the Magnetic Anisotropy in FeII, CoII, and NiII Single‐Ion Magnets
Authors: Sarkar Arup , Dey Sourav , Rajaraman Gopalan
Published: July 2020

Since the last decade, the focus in the area of single‐molecule magnets (SMMs) has been shifting constructively towards the development of single‐ion magnets (SIMs) based on transition metals and lanthanides. Although ground‐breaking results have been witnessed for DyIII‐based SIMs, significant results have also been obtained for some mononuclear transition metal SIMs. Among others, studies based on CoII ion are very prominent as they often exhibit high magnetic anisotropy or zero‐field splitting parameters and offer a large barrier height for magnetisation reversal. Although CoII possibly holds the record for having the largest number of zero‐field SIMs known for any transition metal ion, controlling the magnetic anisotropy in these systems are is still a challenge. In addition to the modern spectroscopic techniques, theoretical studies, especially ab initio CASSCF/NEVPT2 approaches, have been used to uncover the electronic structure of various CoII SIMs. In this article, with some selected examples, the aim is to showcase how varying the coordination number from two to eight, and the geometry around the CoII centre alters the magnetic anisotropy. This offers some design principles for the experimentalists to target new generation SIMs based on the CoII ion. Additionally, some important FeII/FeIII and NiII complexes exhibiting large magnetic anisotropy and SIM properties are also discussed.
COVID‐19 outcomes of patients with gynecologic cancer in New York City
Authors: Lara Olivia D. , O’Cearbhaill Roisin E. , Smith Maria J. , Sutter Megan E. , Knisely Anne , McEachron Jennifer , Gabor Lisa R. , Jee Justin , Fehniger Julia E. , Lee Yi‐Chun , Isani Sara S. , Wright Jason D. , Pothuri Bhavana
Published: July 2020

Background

New York City (NYC) is the epicenter of severe acute respiratory syndrome coronavirus 2 (coronavirus disease 2019 [COVID‐19]) in the United States. Clinical characteristics and outcomes of vulnerable populations, such as those with gynecologic cancer who develop COVID‐19 infections, is limited.

Methods

Patients from 6 NYC‐area hospital systems with known gynecologic cancer and a COVID‐19 diagnosis were identified. Demographic and clinical outcome data were abstracted through a review of electronic medical records.

Results

Records for 121 patients with gynecologic cancer and COVID‐19 were abstracted; the median age at the COVID‐19 diagnosis was 64.0 years (interquartile range, 51.0‐73.0 years). Sixty‐six of the 121 patients (54.5%) required hospitalization; among the hospitalized patients, 45 (68.2%) required respiratory intervention, 20 (30.3%) were admitted to the intensive care unit, and 9 (13.6%) underwent invasive mechanical ventilation. Seventeen patients (14.0%) died of COVID‐19 complications. No patient requiring mechanical ventilation survived. On multivariable analysis, hospitalization was associated with an age ≥64 years (risk ratio [RR], 1.73; 95% confidence interval [CI], 1.18‐2.51), African American race (RR, 1.56; 95% CI, 1.13‐2.15), and 3 or more comorbidities (RR, 1.43; 95% CI, 1.03‐1.98). Only recent immunotherapy use (RR, 3.49; 95% CI, 1.08‐11.27) was associated with death due to COVID‐19 on multivariable analysis; chemotherapy treatment and recent major surgery were not predictive of COVID‐19 severity or mortality.

Conclusions

The case fatality rate among gynecologic oncology patients with a COVID‐19 infection is 14.0%. Recent immunotherapy use is associated with an increased risk of mortality related to COVID‐19 infection.

Lay Summary

The case fatality rate among gynecologic oncology patients with a coronavirus disease 2019 (COVID‐19) infection is 14.0%; there is no association between cytotoxic chemotherapy and cancer‐directed surgery and COVID‐19 severity or death.

As such, patients can be counseled regarding the safety of continued anticancer treatments during the pandemic. This is important because the ability to continue cancer therapies for cancer control and cure is critical.
Aortic root thrombus after left ventricular assist device implantation and aortic valve replacement
Authors: Veenis Jesse F. , Brugts Jasper J. , Yalcin Yunus C. , Roest Stefan , Bekkers Jos A. , Manintveld Olivier C. , Constantinescu Alina A. , Bogers Ad J.J.C. , Zijlstra Felix , Caliskan Kadir
Published: July 2020

Data on the risk of aortic root thrombosis in patients with aortic valve replacement (AVR) and left ventricular assist device (LVAD) surgery are scarce. Two out of nine patients receiving AVR concomitant with LVAD surgery and two out of two patients receiving AVR on LVAD support, at our centre, developed an aortic root thrombus, all diagnosed with computed tomography (CT) angiography. These results demonstrate that patients with concomitant AVR and LVAD surgery, or AVR on LVAD support, have an increased risk of aortic root thrombosis. Therefore, early anti‐thrombotic therapy and vigilant diagnostic follow‐up, using CT scans, are warranted to prevent thromboembolic events.
Unveiling outcomes in coexisting severe aortic stenosis and transthyretin cardiac amyloidosis
Authors: Rosenblum Hannah , Masri Ahmad , Narotsky David L. , Goldsmith Jeff , Hamid Nadira , Hahn Rebecca T. , Kodali Susheel , Vahl Torsten , Nazif Tamim , Khalique Omar K. , Bokhari Sabahat , Soman Prem , Cavalcante João L. , Maurer Mathew S. , Castaño Adam
Published: July 2020

Aims

Advances in diagnostic imaging have increased the recognition of coexisting transthyretin cardiac amyloidosis (ATTR‐CA) and severe aortic stenosis (AS), with a reported prevalence between 8–16%. In this prospective study, we aimed to evaluate the implications of ATTR‐CA on outcomes after transcatheter aortic valve replacement (TAVR).

Methods and results

At two academic centres, we screened patients with severe AS undergoing TAVR for ATTR‐CA. Using Kaplan–Meier analysis, we compared survival free from death and a combined endpoint of death and first heart failure hospitalization between patients with and without ATTR‐CA. Cox proportional‐hazards models were used to determine the association of ATTR‐CA with these endpoints. The rate of heart failure hospitalization was compared amongst those with and without ATTR‐CA. Overall, 204 patients (83 years, 65% male, Society of Thoracic Surgeons score 6.6%, 72% New York Heart Association class III/IV) were included, 27 (13%) with ATTR‐CA. Over a median follow‐up of 2.04 years, there was no difference in mortality (log rank, P = 0.99) or the combined endpoint (log rank, P = 0.79) between patients with and without ATTR‐CA. In Cox proportional‐hazards models, the presence of ATTR‐CA was not associated with death. However, patients with ATTR‐CA had increased rates of heart failure hospitalization at 1 year (0.372 vs. 0.114 events/person‐year, P < 0.004) and 3 years (0.199 vs. 0.111 events/person‐year, P = 0.087) following TAVR.

Conclusion

In moderate‐risk patients with severe AS undergoing TAVR, there was a 13% prevalence of ATTR‐CA, which did not affect mortality. The observed increase in heart failure hospitalization following TAVR in those with ATTR‐CA suggests the consequences of the underlying infiltrative myopathy.
Gallium Fluoride Complexes with Acyclic Bispicolinic Ligands as Potential New Fluorine‐18 Labelled Imaging Agents
Authors: Koay HuiJing , Haskali Mohammad B. , Roselt Peter D. , White Jonathan M. , Donnelly Paul S.
Published: July 2020

The positron‐emitting radionuclide, fluorine‐18, is used to radiolabel molecules to develop tracers for diagnostic imaging with positron‐emission tomography. There is growing interest in the potential of using strong coordinate bonds between electropositive Ga(III) and electronegative fluoride (≈ 557 kJ/mol) to provide new methods of incorporating fluorine‐18 into molecules. The potential of gallium(III) complexes with acyclic pentadentate bispicolinic acid containing ligands (H2L1–3) to form ternary complexes with fluoride, [GaL1–3F] was investigated with a view to developing new methods for fluorine‐18 radiolabelling. A solid‐phase peptide synthesis approach was used to produce a bispicolinic acid chelator with a lysine residue. Characterisation of [GaL1X] (X = OH, Cl, F) by X‐ray crystallography revealed that L1 acted as dianionic N2O2 donor to the Ga(III) with the fifth site occupied by a monodentate anion (OH–, Cl– or F–). Despite its high stability in aqueous mixture and [D6]DMSO and the straightforward synthesis of [GaL1F], it was only possible to form the radioactive analogue [18F][GaL1F] in low radiochemical yields.
Photophysical and Chiroptical Properties of the Enantiomers of N,N'‐Bis(1‐phenylpropyl)‐2,6‐pyridinecarboxamide and their Chiral 9‐Coordinate Ln3+ Complexes
Authors: Chang Victoria Y. , Calvinho Karin U. D. , Tovar Roberto C. , Johnson Victoria A. , Straus Daniel A. , Muller Gilles
Published: July 2020

The R,R and S,S enantiomers of N,N'‐bis(1‐phenylpropyl)‐2,6‐pyridinedicarboxamide, L(Et), react with Ln3+ ions (Ln = La, Eu, Gd, and Tb) to give stable [Ln((R,R)‐ and (S,S)‐L(Et))3]3+ in anhydrous acetonitrile solution, as evidenced by various spectroscopic measurements, including NMR and luminescence titrations. In addition to the characteristic Eu3+ and Tb3+ luminescence bands, the steady‐state and time‐resolved luminescence spectra of the aforementioned complexes show the residual ligand‐centered emission of the 1ππ* to 3ππ* states, indicating an incomplete intersystem crossing (ISC) transfer from the 1ππ* to 3ππ* and ligand‐to‐Ln3+ energy transfer, respectively. The high circularly polarized luminescence (CPL) activity of [Eu(L(Et))3]3+ confirms that using a single enantiomer of L(Et) induces the preferential formation of one chiral [Eu(L(Et))3]3+ complex, consistent with the [EuL3]3+ complexes formed with other ligands derived from a 2,6‐pyridine dicarboxamide moiety. Furthermore, the CPL sign patterns of complexes with (R,R) or (S,S) enantiomer of L(Et) are consistent with the CPL sign pattern of related [LnL3]3+ complexes with the (R,R) or (S,S) enantiomer of the respective ligands in this family.
Chemistry, Computers, and the Mind
Authors: Marsili Mario
Published: July 2020

Almost five decades ago, the first proposals of computer programs meant to reproduce man's chemical knowledge in organic chemistry became known. They were products of what was then called Artificial Intelligence (AI) research, a section of computer science that takes on the controversial task of mechanizing human perception and thought; the human mind. This essay describes some of the key elements of this effort, pointing at specific features that involve the mind in creating and working with chemical software. A brief proposal of whether the neurochemistry in our mind works according to quantum mechanical laws, rather than logical laws, as in a binary computer, is given (Neural Quantum Superposition).
Spatiotemporal graph convolutional recurrent networks for traffic matrix prediction
Authors: Zhao Jianlong , Qu Hua , Zhao Jihong , Dai Huijun , Jiang Dingchao
Published: July 2020

Through accurate network‐wide traffic prediction, network operators can agilely manage resources and improve robustness by proactively adapting to new traffic patterns, especially for traffic engineering, capacity planning and quality of service provisioning. However, due to the proliferation of backbone network traffic as well as the complexity and dynamics of network communication behavior, accurate and effective network‐wide traffic prediction is challenging. To address the challenges, this paper focuses on short‐term traffic matrix (TM) prediction in large‐scale IP backbone networks. In order to improve the prediction performance, a novel spatiotemporal graph convolutional recurrent network (SGCRN)—a deep learning framework that incorporates both spatial and temporal dependencies of traffic flows, is proposed to implement TM prediction with high accuracy and efficiency. By learning network‐wide traffic as graph‐structured TM time series, SGCRN jointly utilizes graph convolutional networks (GCN) and gated recurrent units (GRU) networks to extract comprehensive spatiotemporal correlations among traffic flows. Specifically, SGCRN employs GCNs to identify structural spatial features of traffic flows by considering topological properties, and utilizes GRUs to implement temporal features learning by considering short and long‐term dynamics of traffic flows. Extensive experimental results on the inter‐Points of Presence network traffic data from four real IP backbone networks show that SGCRN can effectively predict short‐term network‐wide TM with superior accuracy compared with other four widely used traffic prediction methods.
Soft furnishing fires: They're still a problem
Authors: Ahrens Marty
Published: July 2020

Home fires in which soft furnishings were first ignited or contributed to fire spread cause a disproportionate share of US home fire deaths. Although the death toll from these fires is much lower than in the 1980s, the rate of death per 1000 reported fires has doubled. Data from the National Fire Incident Reporting System and the National Fire Protection Association's annual Fire Experience Survey were used to create national estimates of these fires and casualties. Including both fires in which upholstered furniture was the item first ignited and contributed most to fire spread, in 2013‐2017, upholstered furniture was involved in an estimated average of 7120 (2%) home fires per year, resulting in an average of 570 (22%) deaths per year. Mattresses or bedding were involved in estimated average of 10 530 (3%) home fires per year, resulting in an average of 370 (14%) deaths annually. In most of these fires and deaths, the item was first ignited. Smoking materials were the leading cause of these fires (20%‐26%) and associated deaths (52%‐54%). Various types of operating equipment and small open flames also play a role. Understanding the causes of these fires is essential to develop new strategies to prevent them.
The effect of pH on the chemical and structural interactions between apple polyphenol and starch derived from rice and maize
Authors: Chou Shurui , Li Bin , Tan Hui , Zhang Weijia , Zang Zhihuan , Cui Huijun , Wang Hanchen , Zhang Shuyi , Meng Xianjun
Published: July 2020

To date, how pH affects starch–polyphenol mixtures has not been thoroughly investigated. This study explored the impact of combining apple polyphenol (AP) with both normal rice starch (NRS) and normal maize starch (NMS) across a range of pH conditions. NRS–AP mixture particle sizes across a pH range of 3–8 varied from 169.9 ± 5.4 to 187.5 ± 6.9 μm, while for NMS–AP particles, these sizes ranged from 161.8 ± 8.0 to 176.0 ± 4.9 μm, indicating that the aggregation of starch–AP was inhibited under low pH condition. The melting enthalpy (△H) values of the NRS–AP mixture across a pH range of 3–8 were 8.50 ± 0.06–9.56 ± 0.12 J/g, while the corresponding value for the NMS–AP mixture was 5.77 ± 0.05–6.21 ± 0.08 J/g. FTIR analyses revealed that the degree of order of these starch–AP mixtures significantly decreased under low pH conditions. XRD analysis further revealed that both NRS–AP and NMS–AP mixtures exhibited V‐type structures, and relative crystallinity levels decreased significantly under low pH conditions. Together, these results indicate that low pH values inhibit the recrystallization of NRS–AP and NMS–AP mixtures. Overall, these findings provide additional evidence regarding the interactions between AP and specific starches under a range of pH conditions.
Effect of Structural Defects and Impurities on the Excited State Dynamics of 2D BA2PbI4 Perovskite
Authors: Gélvez‐Rueda María C. , Peeters Sicco , Wang Peng‐Cheng , Felter Kevin M. , Grozema Ferdinand C.
Published: July 2020

In this work, we show that the quality of the precursor and the thin film preparation strongly affect the optoelectronic properties of the 2D perovskite BA2PbI4. 2D perovskites with alkylammonium organic cations such as butylammonium (BA) are relatively soft structures that exhibit large dynamic disorder and phase variations. Here we show, by a variety of spectroscopy techniques (steady state absorption, photoluminescence and ultrafast transient absorption), that at temperatures below the phase transition (253 K) the material exhibits excitonic features from the room temperature phase (due to incomplete structural transition) and a broadband emission at 560–600 nm (due to self‐trapped excitons) with varied relative intensities depending on the precursors and processing conditions. This suggests that the processing conditions have a large influence on the crystallization and introduction of extrinsic defect impurities directly affecting the optoelectronic properties. Making absolute statements about the properties of BA2PbI4 requires improved control over the materials thin film deposition and a better understanding of the role of the lattice vibrational dynamics and extrinsic defects on the exciton dynamics.
Exact solutions of micropolar SWCNTs nanofluid with heat transfer
Authors: Irfan Haider Muhammad , Imran Asjad Muhammad , Aleem Maryam , Hussanan Abid
Published: July 2020

The present study is aimed to analyze the unsteady micropolar nanofluid flow passing over an oscillating infinite vertical plate. The flow is affected by thermal radiation and Newtonian heating. Single‐walled carbon nanotubes (SWCNTs) are added to enrich the thermal properties of the micropolar fluid. Kerosene is taken as the base liquid to enhance heat transfer. By using dimensional analysis, the governing equations for temperature, velocity, and microrotation are reduced to dimensionless form and after that, these equations have been solved by applying Laplace transform method to get the exact solutions. Finally, we have presented the effects of material and flow parameters and illustrated graphically by the Mathcad software. We found that microrotation, temperature, and velocity are decreasing functions of Prandtl number but have shown increasing behavior for Grashof number. Furthermore, we found that SWCNTs‐water‐based nanofluid has a comparatively higher heat transfer rate than SWCNTs‐kerosene and SWCNTs‐engine oil‐based nanofluids.
Do the macroeconomic factors influence the firm's investment decisions? A generalized method of moments (GMM) approach
Authors: Farooq Umar , Ahmed Jaleel , Khan Shamshair
Published: July 2020

The study checks association between the macroeconomic factors and corporate investment decision by using 10 years of data (2007–2016) of 12 Asian countries. There exist the series of studies, which discuss the firm‐level determinants of investment but very few studies have found the relationship between macroeconomic factors and corporate investment. So, with specific data set, this study is an attempt to fill this instant gap by exploring the relationship between macroeconomic factors and firm capital investment. GMM approach uses for estimation purposes. The results imply that increases in inflation rate decrease the investment due to increment in future cost of investment. Similarly, high interest rate decreases the corporate capital investment due to opportunistic options of early returns by investing in high interest income securities. The firms from high GDP growth countries carry higher investment level owing to business acceleration. However, the firms from high FDI inflow countries bear the low investment opportunities attributed to suppressed fierce competition. The countries having developed financial sector encourage their firms to invest more in banking securities instead of investing in physical long‐term investment, that is, investment in fixed assets due to professional management of funds by financial institutions and low substantial risks. Briefly, the findings of the study recommend that the corporate managers should focus on economic sensitivity while making decisions about any potential investment.
Suppuration as diagnostic criterium of peri‐implantitis
Authors: Monje Alberto , Vera Maria , Muñoz‐Sanz Agustín , Wang Hom‐Lay , Nart José
Published: July 2020

Background

Suppuration (SUP) as a diagnostic parameter for monitoring dental implants is not yet well understood. The retrospective clinical and radiographic study was therefore performed to investigate the patient, implant, and site characteristics among individuals exhibiting SUP.

Methods

Demographic characteristics and clinical parameters were recorded. Radiographic features were analyzed using cone‐beam computed tomography. Peri‐implantitis was defined based on the consensus report of Workgroup 4 of the 2017 World Workshop on the Classification of Periodontal and Peri‐Implant Diseases and Conditions: probing depth (PD) ≥6 mm, presence of bleeding and/or SUP on gentle probing, and radiographic marginal bone loss (MBL) ≥3 mm. SUP was graded according to profuseness (dot versus line/drop) and time after probing (≥15 seconds versus <15 seconds after probing versus spontaneous). Simple binary logistic regression models were estimated using generalized estimation equations to explain the probability of SUP based on demographic, clinical, and radiographic variables.

Results

A total of 111 eligible patients (nimplants = 501) were assessed. Of them, 57 (nimplants = 334) were diagnosed with peri‐implantitis according to the established case definition, and of these individuals, 31 (nimplants = 96) presented SUP. Therefore, the prevalence of SUP was 27.92% in the total sample size and 54.38% in peri‐implantitis patients. Overall, 28.74% implants displayed SUP within patients with peri‐implantitis. SUP was more frequently found at buccal sites (51%) and proved less prevalent at mesio‐lingual sites (16.7%). Defect morphology (OR = 6.59; P = 0.004), PD (OR = 1.63; P = 0.024), and MBL (OR = 1.35; P = 0.010) were significantly associated with the presence of SUP. Likewise, defect morphology (P = 0.02), PD (P = 0.003), and MBL (P = 0.01) were significantly correlated with the grade of SUP.

Conclusion

The presence and grade of SUP are associated with peri‐implant bone loss, probing depth, and defect morphology in patients with peri‐implantitis.
Iron overload as a risk factor for poor graft function following allogeneic hematopoietic stem cell transplantation
Authors: Wu Xue‐Qiong , Lin Kang‐Ni , Chen Min‐Min , Jiang Pei‐Fang , Zhang Yu‐Xin , Chen Yong‐Quan , Chen Qiu‐Ru , Xiao Min , Zhu Hao‐Jie , Issa Hajji Ally , Chen Shao‐Zhen , Luo Xiao‐Feng , Ren Jin‐Hua , Li Qian , Zeng Yan‐Ling , Xu Jing‐Jing , Lin Yi‐Feng , Zheng Rong , Zheng Zhi‐Hong , Chen Zhi‐Zhe , Hu Jian‐Da , Yang Ting
Published: July 2020

Hematological malignancies are increasingly treated with allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Unfortunately, iron overload is a frequent adverse effect of allo‐HSCT and is associated with poor prognosis. In the present study, we investigated hematopoiesis in iron‐overloaded mice and elucidated the effects of iron overload on the bone marrow (BM) microenvironment. Iron‐overloaded BALB/C mice were generated by injecting 20 mg/mL saccharated iron oxide intraperitoneally. Hematoxylin‐eosin staining was performed to evaluate the effects of an iron overload in mice. BM cells obtained from C57BL/6 mice were transplanted into irradiated BALB/C mice (whole‐body irradiation of 4 Gy, twice with a 4‐hours interval) by tail vein injection. Two weeks after allo‐HSCT, the hematopoietic reconstitution capacity was evaluated in recipients by colony‐forming assays. Histopathological examinations showed brown‐stained granular deposits, irregularly arranged lymphocytes in the liver tissues, and blue‐stained blocks in the BM collected from mice received injections of high‐dose saccharated iron oxide (20 mg/mL). Iron‐overloaded mice showed more platelets, higher‐hemoglobin (HGB) concentration, fewer granulocyte‐macrophage colony‐forming units (CFU‐GM), erythrocyte colony‐forming units (CFU‐E), and mixed granulocyte/erythrocyte/monocyte/megakaryocyte colony‐forming units (CFU‐mix) than healthy mice. Iron‐overloaded recipients presented with reduced erythrocytes and HGB concentration in peripheral blood, along with decreased marrow stroma cells, CFU‐GM, CFU‐E, and CFU‐mix relative to healthy recipients. Taken together, our findings demonstrate that iron overload might alter the number of red blood cells after transplantation in mice by destroying the BM microenvironment, thereby affecting the recovery of BM hematopoietic function.
Sequence‐Controlled Synthesis of Advanced Clickable Synthetic Oligonucleotides
Authors: Han Xun , Fairbanks Benjamin D. , Sinha Jasmine , Bowman Christopher N.
Published: July 2020

Through thiol‐ene photopolymerization of presynthesized oligomers, advanced clickable nucleic acids (CNA‐2G) are synthesized with sequence‐controlled repeating units. As examples, poly(thymine‐adenine) (polyTA) CNA‐2G and poly(thymine‐thymine‐cytosine) CNA‐2G are synthesized by polymerizing thiol‐ene heterofunctional dimers with pendant thymine‐adenine nucleobases and trimer with pendant thymine‐thymine‐cytosine nucleobases. Based on size exclusion chromatography (SEC) analysis, polyTA and polyTTC have number average molecular weights of 2000 and 1800, respectively, which contain 7–8 pendant nucleobases. Based on the different behavior of the CNA‐2G monomers and CNA‐2G oligomers with two or more pendant nucleobases in photopolymerization, an unusual thiol‐ene chain‐growth propagation mechanism is observed for the former and a common thiol‐ene step‐growth propagation mechanism for the latter. The uncommon thiol‐ene chain‐growth propagation is hypothesized to rely on a six‐membered ring mediated intramolecular hydrogen atom transfer process.
The impact of online low search costs on firms' incentives to invest in quality
Authors: Badra Yassine
Published: July 2020

The growing use of the Internet has made search costs lower for consumers. We study the effect of this on the incentives for firms to invest in quality. We assume that there are firms producing high‐quality products and others producing low‐quality products; we also assume that the market share of the latter is higher than that of the former. Besides, we analyse the changes of both the revenue effect and the quantity effect; we show that they go in the same nonintuitive direction. In other words, when search costs decrease, the incentives to invest in quality increase.
Fast implicit difference schemes for time‐space fractional diffusion equations with the integral fractional Laplacian
Authors: Gu Xian‐Ming , Sun Hai‐Wei , Zhang Yanzhi , Zhao Yong‐Liang
Published: July 2020

In this paper, we develop two fast implicit difference schemes for solving a class of variable‐coefficient time–space fractional diffusion equations with integral fractional Laplacian (IFL). The proposed schemes utilize the graded L1 formula for the Caputo fractional derivative and a special finite difference discretization for IFL, where the graded mesh can capture the model problem with a weak singularity at initial time. The stability and convergence are rigorously proved via the M‐matrix analysis, which is from the spatial discretized matrix of IFL. Moreover, the proposed schemes use the fast sum‐of‐exponential approximation and Toeplitz matrix algorithms to reduce the computational cost for the nonlocal property of time and space fractional derivatives, respectively. The fast schemes greatly reduce the computational work of solving the discretized linear systems from
by a direct solver to
per preconditioned Krylov subspace iteration and a memory requirement from 𝒪(MN2) to 𝒪(NNexp), where N and (Nexp ≪) M are the number of spatial and temporal grid nodes, respectively. The spectrum of preconditioned matrix is also given for ensuring the acceleration benefit of circulant preconditioners. Finally, numerical results are presented to show the utility of the proposed methods.