bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconfigurable and Recyclable Circuits Based on Liquid Passive Components
Authors: Gao Naiwei , Wu Xun , He Yonglin , Ma Qiang , Wang Yapei
Published: July 2020

Liquid conductors are an intriguing substitute for traditional solid‐state materials for fabricating reconfigurable and recyclable circuits in electronic devices. However, most liquid conductors are costly and suffer from low conductivity that immensely slows their development in liquid reactance elements. Here, a solvated ionic liquid (SIL) with low cost and high conductivity is formulated by employing hydrogen‐bonding complex between 1‐butyl‐3‐methylimidazolium chloride and ethylene glycol. This SIL can be used for manufacturing liquid passive components such as resistors, inductors, and capacitors, which can be easily assembled into electronic devices with signal filtering functions. In addition, fluidic circuits have great potential for building a woven dynamic circuit that allows to handle various tasks under the same electronic module. This strategy opens an avenue for expanding the usage of liquid conductors to broader electronics designs.
Two‐Step Plasma Treatment Designed for High‐Performance Flexible Amorphous ZnAlSnO Thin‐Film Transistors Replacing Thermal Annealing
Authors: Lu Rongkai , Lu Jianguo , Wei Xishuo , Yue Shilu , Li Siqin , Lu Bojing , Zhao Yi , Zhu Liping , Chen Lingxiang , Ye Zhizhen
Published: July 2020

A two‐step plasma treatment is designed as a post‐process treatment for active layers of flexible thin‐film transistors (TFTs) instead of thermal post‐annealing. Amorphous zinc‐aluminum‐tin‐oxide (ZATO) is used for active layers of flexible TFTs, which highlights the influence of the two‐step plasma treatment on ZATO films and the corresponding TFT devices, because the device performance of ZATO TFTs exhibits significant improvement only after the active layers are annealed at high temperature. The effects of various plasma‐treatment of the ZATO active layer on the device performance are studied in detail. The two‐step plasma treatment can ameliorate the amorphous film and improve the corresponding device performance. The flexible TFT device with ZATO active layer processed by the two‐step plasma treatment exhibits an Ion/Ioff current ratio of 1.15 × 108, a positive threshold voltage of 3.77 V, a field‐effect mobility of 13.2 cm2 V−1 s−1, and a subthreshold swing of 0.5 V per decade. Meanwhile, a correlation is found that the effect of the two‐step plasma treatment as post‐process treatment of amorphous ZATO films is almost equivalent to 500 °C annealing, by comparing the electrical properties of TFTs with ZATO active layers annealed at different temperature. The two‐step plasma treatment may replace high‐temperature annealing in the thermosensitive process.
Emerging Superconductivity and the Origin of Its Enhancement in Pressurized Topological Nodal‐Line Semimetal SrAs3
Authors: Qi Mengyao , Zhu Xiangde , Zhou Yonghui , An Chao , Chen Chunhua , Yuan Yifang , Zhang Bowen , Wang Shuyang , Zhou Ying , Chen Xuliang , Zhang Ranran , Tian Mingliang , Yang Zhaorong
Published: July 2020

Topological nodal‐line semimetal SrAs3 hosts a simple nodal loop on the verge of Fermi level without distracting trivial states, providing a good platform for further investigations of electronic quantum states. Here, a report on pressure‐driven superconductivity in SrAs3 single crystal is provided and the interplay between the crystal structure, electronic state, and superconductivity is clarified therein. The comprehensive high‐pressure experiments, i.e., synchrotron X‐ray diffraction, electrical transport, and Raman spectroscopy, consistently reveal a critical pressure Pc ≈ 25 GPa. Around Pc, a superconducting transition appears, concomitant with the formation of high‐pressure cubic Pm‐3m phase. Meanwhile, the superconducting transition temperature Tc and hole carrier density increase synchronously above Pc. This finding demonstrates that the emerging superconductivity in SrAs3 stems from the high‐pressure cubic phase on the one hand, and shows that the evolution of Tc(P) is intimately correlated with the enhanced density of states near the Fermi level on the other hand.
An Enzymatic Platform for the Highly Enantioselective and Stereodivergent Construction of Cyclopropyl‐δ‐lactones
Authors: Ren Xinkun , Liu Ningyu , Chandgude Ajay L. , Fasan Rudi
Published: July 2020

Abiological enzymes offers new opportunities for sustainable chemistry. Herein, we report the development of biological catalysts derived from sperm whale myoglobin that exploit a carbene transfer mechanism for the asymmetric synthesis of cyclopropane‐fused‐δ‐lactones, which are key structural motifs found in many biologically active natural products. While hemin, wild‐type myoglobin, and other hemoproteins are unable to catalyze this reaction, the myoglobin scaffold could be remodeled by protein engineering to permit the intramolecular cyclopropanation of a broad spectrum of homoallylic diazoacetate substrates in high yields and with up to 99 % enantiomeric excess. Via an alternate evolutionary trajectory, a stereodivergent biocatalyst was also obtained for affording mirror‐image forms of the desired bicyclic products. In combination with whole‐cell transformations, the myoglobin‐based biocatalyst was used for the asymmetric construction of a cyclopropyl‐δ‐lactone scaffold at a gram scale, which could be further elaborated to furnish a variety of enantiopure trisubstituted cyclopropanes.
Recent Advances in Catalytic Hydrosilylations: Developments beyond Traditional Platinum Catalysts
Authors: de Almeida Leandro Duarte , Wang Hongli , Junge Kathrin , Cui Xinjiang , Beller Matthias
Published: July 2020

Hydrosilylation reactions, which allow the addition of Si−H to C=C/C≡C bonds, are typically catalyzed by homogeneous noble metal catalysts (Pt, Rh, Ir, and Ru). Although excellent activity and selectivity can be obtained, the price, purification, and metal residues of these precious catalysts are problems in the silicone industry. Thus, a strong interest in more sustainable catalysts and for more economic processes exists. In this respect, recently disclosed hydrosilylations using catalysts based on earth‐abundant transition metals, for example, Fe, Co, Ni, and Mn, and heterogeneous catalysts (supported nanoparticles and single‐atom sites) are noteworthy. This minireview describes the recent advances in this field.
Meta Junction Promoting Efficient Thermally Activated Delayed Fluorescence in Donor‐Acceptor Conjugated Polymers
Authors: Rao Jiancheng , Yang Liuqing , Li Xuefei , Zhao Lei , Wang Shumeng , Ding Junqiao , Wang Lixiang
Published: July 2020

The meta junction is proposed to realize efficient thermally activated delayed fluorescence (TADF) in donor–acceptor (D‐A) conjugated polymers. Based on triphenylamine as D and dicyanobenzene as A, as a proof of concept, a series of D‐A conjugated polymers has been developed by changing their connection sites. When the junction between D and A is tuned from para to meta, the singlet–triplet energy splitting (ΔEST) is found to be significantly decreased from 0.44 to 0.10 eV because of the increasing hole–electron separation. Unlike the para‐linked analogue with no TADF, consequently, the meta‐linked polymer shows a strong delayed fluorescence. Its corresponding solution‐processed organic light‐emitting diodes (OLEDs) achieve a promising external quantum efficiency (EQE) of 15.4 % (51.9 cd A−1, 50.9 lm W−1) and CIE coordinates of (0.34, 0.57). The results highlight the bright future of D‐A conjugated polymers used for TADF OLEDs.
An Electrochemical Biosensor Architecture Based on Protein Folding Supports Direct Real‐Time Measurements in Whole Blood
Authors: Kurnik Martin , Pang Eric Z. , Plaxco Kevin W.
Published: July 2020

The ability to monitor drug and biomarker concentrations in the body with high frequency and in real time would revolutionize our understanding of biology and our capacity to personalize medicine. The few in vivo molecular sensors that currently exist, however, all rely on the specific chemical or enzymatic reactivity of their targets and thus are not generalizable. In response, we demonstrate here an electrochemical sensing architecture based on binding‐induced protein folding that is 1) independent of the reactivity of its targets, 2) reagentless, real‐time, and with a resolution of seconds, and 3) selective enough to deploy in undiluted bodily fluids. As a proof of principle, we use the SH3 domain from human Fyn kinase to build a sensor that discriminates between the protein's peptide targets and responds rapidly and quantitatively even when challenged in whole blood. The resulting sensor architecture could drastically expand the chemical space accessible to continuous, real‐time biosensors.
Fe3O4‐Lignin@Pd‐NPs: A highly efficient, magnetically recoverable and recyclable catalyst for Mizoroki‐Heck reaction under solvent‐free conditions
Authors: Madrahalli Bharamanagowda Marulasiddeshwara , Panchangam Raghavendra Kumar
Published: July 2020

Palladium nanoparticles (Pd‐NPs) were synthesized under green conditions in water by chemical reduction of PdCl2 with NaOH and supported by Fe3O4‐Lignin. Fe3O4‐Lignin is an organic–inorganic hybrid core‐shell was synthesized by sonication of a mixture of Fe3O4‐NPs (20 nm) and alkali lignin. The new materials Fe3O4‐Lignin and Fe3O4‐Lignin@Pd‐NPs were characterized by PXRD, SEM and FT‐IR spectroscopy. The Fe3O4‐Lignin@Pd‐NPs was further confirmed by UV–Visible spectroscopy, TEM, EDX, HRICP‐AES and TGA/DTA. The average size of Pd‐NPs determined from PXRD was 5–10 nm. The amount of palladium loaded on Fe3O4‐Lignin obtained from EDX analysis was 26.63% by mass. The amount of Fe and Pd present in the catalyst obtained from HRICP‐AES was 11.88 (wt. %) and 10.90 (wt. %) respectively per gram of lignin. The catalytic potential of Fe3O4‐Lignin@Pd‐NPs was evaluated in Mizoroki‐Heck C‐C coupling reaction. During the optimization studies of reaction between iodobenzene and n‐butyl acrylate in various solvents and under solvent‐free but aerobic conditions using various inorganic and organic bases, the product n‐butyl 3‐phenylprop‐2‐enoate (1a) obtained was as high as 95% in highly polar solvents as short as in 10 min and 99% under solvent‐free conditions in 3 min at 140 °C using n‐Pr3N as base. The scope of the above catalyst was investigated in the Mizoroki‐Heck reaction of various aryl/heterocyclic halides and n‐butyl acrylate/styrene under optimized solvent‐less conditions. The corresponding products were obtained in high yields (73–99%). The catalyst recovered by magnetic decantation was reused for five times in the C‐C coupling reaction between iodobenzene and n‐butyl acrylate which yielded 90–95% of the desired product, 1a.
Cu2O/reduced graphene oxide/TiO2nanomaterial: An effective photocatalyst for azide‐alkyne cycloaddition with benzyl halides or epoxide derivatives under visible light irradiation
Authors: Mirza‐Aghayan Maryam , Saeedi Mandana , Boukherroub Rabah
Published: July 2020

Cu2O/reduced graphene oxide/TiO2(Cu2O/rGO/TiO2) photocatalyst was synthesized under ultrasonic irradiation. The nanomaterial was identified by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT‐IR) spectroscopy, UV–vis absorption, and inductively coupled plasma optical emission spectroscopy (ICP‐OES). The Cu2O/rGO/TiO2photocatalyst was utilized in “click” reaction for the preparation of 1,4‐disubstituted 1,2,3‐triazoles via one pot multicomponent reaction of benzyl halide or epoxide derivatives with alkynes in presence of NaN3and triethylamine under visible light irradiation. The “click” reaction was performed under mild conditions affording good to excellent yields of the triazole compounds using low catalyst loading in short reaction times. The nanocomposite was recovered and recycled for five successive runs without a major diminution in its catalytic performance.
Enhanced liquid mixing in T‐mixer having staggered fins
Authors: Tan Sak Jie , Yu Kok Hwa , Ismail Mohd Azmi , Teoh Yew Heng
Published: July 2020

The present study considers computational evaluation of mixing performance in a T‐mixer having staggered fins. A novel arrangement consisting of two pairs of staggered fins is incorporated and placed close to the entrance of the mixing channel. A parametric study is performed to examine the effects arising from the geometric and flow parameters alteration. With respect to all the parameters investigated, the presence of staggered fins consistently give rise to better mixing performance as compared with that without fin. With the presence of fins, flow of liquid with different species concentrations is redirected and aligned with the angle of inclination θ of the fins, creating lateral convection that disrupt the flow. This promotes better mixing of liquids. At Re = 1, staggered fins arrangement with θ = 45°, enhancement in mixing efficiency can reach as high as 33.3% as compared with that of without fin. It is also interesting to note that liquid mixing enhancement is significant at higher Reynolds numbers (1 ≤ Re ≤ 10) as compared with that of low Reynolds value (Re < 1).
Antibacterial Polyelectrolytic chitosan derivatives conjugated natural rubber latex films with minimized bacterial adhesion
Authors: Arakkal Aswin , Aazem Irthasa , Honey Gopinathan , Vengellur Ajith , Bhat Sarita G. , S. Sailaja Gopalakrishnan Chettiar
Published: July 2020

Water soluble polyelectrolytic derivatives of chitosan (CDs) with carboxyl (COO−) and quaternary ammonium (NH4+) groups were synthesized and characterized by NMR, FT‐IR, TGA and zeta potential analyses; while degree of substitution was determined by potentiometric titrations. Both CDs in the as‐synthesized form exhibited antibacterial zones against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The CD conjugated vulcanized natural rubber latex (NRL) films were investigated for understanding the level of bacterial adhesion and bactericidal properties as a function of the polyelectrolytic groups present. NRL Films modified at ambient conditions were found effective against Pseudomonas aeruginosa (P. aeruginosa). The biofilm assay results demonstrate that CD conjugated samples exhibit significantly reduced adhesion (63.8%) against P. aeruginosa. Further, alterations observed in cellular morphology of attached bacteria indicate that the modified surface of films is bacteriocidal while presence of significantly higher level of extra cellular polymer substances (EPS) were detected on control NRL films.
Diet composition of the Italian crested newt (Triturus carnifex) in structurally different artificial ponds based on stomach contents and stable isotope analyses
Authors: Careddu Giulio , Carlini Nicolò , Romano Antonio , Rossi Loreto , Calizza Edoardo , Sporta Caputi Simona , Costantini Maria Letizia
Published: July 2020

In order to evaluate the effects of ecological disturbances, such as climate change, human‐induced habitat modification, or species introduction, and in order to adopt appropriate management policies for their conservation, knowledge of the trophic ecology of protected or threatened species is crucial. The Italian crested newt,Triturus carnifex(Laurenti, 1768), is listed in annexes II and IV of the European Habitats Directive. For this species, changes in water quality and habitat loss represent major threats, potentially impairing its breeding and feeding activities.

Artificial aquatic habitats, such as cattle‐drinking pools, represent valuable refuges and suitable breeding sites forT. carnifex. The aim of this study was to determine the food niche of the Italian crested newt in these habitats, evaluating its prey selection strategy in relation to a range of environmental conditions and differing availability of resources. Stomach contents (indicative of short‐term diet) andδ13C andδ15N signatures of tails (indicative of medium‐term diet) of adult newts from three artificial ponds in central Italy, where traditional silvo‐pastoral activities are still important, were determined. Potential prey were also sampled and processed for stable isotope analysis.

Triturus carnifex,similar to other newt species, is an opportunistic predator, feeding on a wide variety of prey that includes terrestrial and aquatic macroinvertebrates. In particular, the opportunistic use of temporally available small zooplankton was identified from stomach contents analysis. Conversely, stable isotope analysis highlighted the consumption of larger, soft‐bodied prey that the stomach‐contents‐based approach underestimated. These included terrestrial oligochaetes, which turned out to be the most important and energy‐rich food source in the medium term.

These results emphasize the usefulness of combined approaches for studying the trophic ecology of salamanders and also highlight the importance of the integrated management of aquatic breeding habitats and neighbouring terrestrial habitats, as sources of food, for newt conservation.
Novel VEGFR‐2 inhibitors with an N‐acylhydrazone scaffold
Authors: Pauli Fernanda P. , Martins Juliana R. , Paschoalin Thaysa , Ionta Marisa , Barbosa Maria Leticia C. , Barreiro Eliezer J.
Published: July 2020

Vascular endothelial growth factor receptor 2 (VEGFR‐2) is a tyrosine kinase that mediates a large number of cell responses associated with angiogenesis. The control of the angiogenic pathway in tumorigenesis by the inhibition of VEGFR‐2 is considered a promising therapeutic strategy for the prevention and control of solid tumor growth. In this study, the design, synthesis, and biological evaluation of a novel series of VEGFR‐2 inhibitors with an N‐acylhydrazone (NAH) scaffold (9a–h) are reported. The molecular design is validated by docking studies and by in vitro inhibitory activity assays. Compounds 9b, 9c, 9d, and 9f effectively inhibited neovascularization induced by VEGF in the chorioallantoic membrane assay. Thus, these NAH derivatives are promising antiangiogenic prototypes.
Analysis of Carbonate Decomposition During Solid Electrolyte Interphase Formation in Isotope‐Labeled Lithium Ion Battery Electrolytes: Extending the Knowledge about Electrolyte Soluble Species
Authors: Peschel Christoph , Horsthemke Fabian , Leißing Marco , Wiemers‐Meyer Simon , Henschel Jonas , Winter Martin , Nowak Sascha
Published: July 2020

Sufficient interphase formation during the first cycles is crucial for the long‐term performance of lithium ion batteries. During the first cycles, electrolyte salt and solvent molecule decomposition caused by electrochemical instabilities leads to a wide range of decomposition species contributing to the formation of performance‐beneficial interphases at the electrodes as well as performance‐impairing side reactions. Due to structural similarities of carbonate educts, elucidation of underlying reaction pathways is complex. In this work, isotope‐labeled ethylene carbonate (13C3−EC) is applied to differentiate contributions of cyclic and linear carbonates to occurring interphase and decomposition reactions. Thereby, carbon atom tracing of electrolyte soluble species is performed by means of gas chromatography‐mass spectrometry (GC−MS). Reaction pathways are postulated based on identified molecular origins. Among others, a new DMC‐EC cross reactivity via lithium ethylene monocarbonate is considered. Moreover, radical reactions resulting in C−C bond formation are investigated and radical polymerizations of stoichiometric equivalents of ethene formed in situ during EC reduction are proposed. Finally, alkyl carbonates with C>4 alkyl chains are identified considering underlying reactivities. Discussed electrolyte decomposition reactions extend the understanding of EC‐based solid electrolyte interphase (SEI) formation emphasizing possible radical reactivities and solvent molecule contributions.
Genetics and signaling mechanisms of orofacial clefts
Authors: Reynolds Kurt , Zhang Shuwen , Sun Bo , Garland Michael A. , Ji Yu , Zhou Chengji J.
Published: July 2020

Craniofacial development involves several complex tissue movements including several fusion processes to form the frontonasal and maxillary structures, including the upper lip and palate. Each of these movements are controlled by many different factors that are tightly regulated by several integral morphogenetic signaling pathways. Subject to both genetic and environmental influences, interruption at nearly any stage can disrupt lip, nasal, or palate fusion and result in a cleft. Here, we discuss many of the genetic risk factors that may contribute to the presentation of orofacial clefts in patients, and several of the key signaling pathways and underlying cellular mechanisms that control lip and palate formation, as identified primarily through investigating equivalent processes in animal models, are examined.
Novel spiking methods developed for anion exchange chromatography operating in a continuous process
Authors: Li Ying , Chang Audrey , Beattie David , Remington Kathryn M.
Published: July 2020

Many manufacturers of biopharmaceuticals are moving from batch to continuous processing. While this approach offers advantages over batch processing, demonstration of viral clearance for continuous processes is challenging. Fluctuating output from a continuous process chromatography column results in a nonhomogeneous load for the subsequent column and must be considered when designing viral clearance studies. One approach to clearance studies is to downscale the connected unit operations and introduce virus by in‐line spiking. This is challenging to be implemented at the contract research organization performing the clearance study given the complexity of systems and level of expertise required. Alternately, each unit operation could be evaluated in traditional batch mode but the spiking and loading conditions be modified to mimic the variance introduced by the transition between two connected columns. Using a standard chromatography system, we evaluated a flow‐through anion exchange chromatography step in a monoclonal antibody (mAb) manufacturing process using five different methods to introduce the virus to the column. Our data show that whether the virus or the mAbs were introduced in concentrated peaks, or as a homogeneous batch, the clearance of mouse minute virus was similar. This study introduces an alternative way to evaluate viral clearance in a continuous process and demonstrates the robustness of anion exchange chromatography unit operating in continuous processing.
Voluntary alcohol consumption is increased in female, but not male, oxytocin receptor knockout mice
Authors: Rodriguez Karla M. , Smith Brittany L. , Caldwell Heather K.
Published: July 2020

Introduction

The oxytocin (Oxt) system, while typically associated with the neural regulation of social behaviors, also plays a role in an individual's vulnerability to develop alcohol use disorders (AUD). In humans, changes to the Oxt system, due to early life experience and/or genetic mutations, are associated with increased vulnerability to AUD. While a considerable amount is known about Oxt's role in AUD in males, less is known or understood, about how Oxt may affect AUD in females, likely due to many clinical and preclinical studies of AUD not directly considering sex as a biological variable. This is unfortunate given that females are more vulnerable to the effects of alcohol and have increased alcohol consumption, as compared to males. Therefore, in the current study we wanted to determine whether genetic disruption of the Oxt receptor (Oxtr), that is, Oxtr knockout (−/−) mice, affected stress‐induced alcohol consumption in males and females. We hypothesized that genetic disruption of the Oxtr would result in increased stress‐induced alcohol consumption in both males and females compared to wild‐type (+/+) controls. Though, we predicted that these disruptions might be greater in female Oxtr −/− mice.

Methods

To test this hypothesis, a two‐bottle preference test was utilized along with the forced swim test (FST), and pre‐ and poststress alcohol consumption and preference measured within each sex (males and females were run separately). As a follow‐up experiment, a taste preference test, to control for possible genotypic differences in taste, was also performed.

Results

In males, we found no significant genotypic differences in alcohol consumption or preference. However, in females, we found that genetic disruption of the Oxtr resulted in a greater consumption of alcohol both pre‐ and poststress compared to controls.

Conclusion

These data suggest that in females, disruptions in Oxt signaling may contribute to increased vulnerability to alcohol‐associated addiction.
A cavotricuspid isthmus pouch revealed to be a breakout site for gap conduction of recurrent common atrial flutter
Authors: Sekihara Takayuki , Sonoura Takuryu , Nakamura Yuka , Sunayama Isamu , Morishita Yu , Ishimi Masashi , Yamato Masashi , Yoshimura Takahiro , Yasuoka Yoshinori
Published: July 2020

A cavotricuspid isthmus pouch can be a breakout site for gap conduction of cavotricuspid isthmus block line. If the previous block line is electrically silent, high‐density 3‐D mapping and pouchgraphy are useful to find the pouch and ablate within it.
Self‐Assembly Behavior of Diacetylenic Acid Molecules upon Vapor Deposition: Odd–Even Effect on the Film Morphology
Authors: Tseng Chiao‐Wei , Huang Ding‐Chi , Yang Han‐Li , Lin Hsieh‐Cheng , Li Fang‐Cheng , Pao Chun‐Wei , Tao Yu‐Tai
Published: July 2020

A series of linear carboxylic acids containing diacetylenic units at different positions along the chain (C12H25(C≡C)2(CH2)nCOOH, n=7–11) were vacuum‐deposited on clean silica substrates. The morphologies of the initial films after UV irradiation were studied. A clear odd–even effect on the morphology of the initial film was observed in that, depending on the spacer length between the diacetylenic unit and carboxyl head group, rings or dendrites of acid dimer layers were obtained. A molecular dynamic simulation of the aggregation process suggests that two competing intermolecular interactions and thus aggregation directions are involved and modulated by the odd or even carbon chain length. Further modulation of the interaction by substitution of a phenyl group at the terminus of the chain or by changing the carboxyl head group to an amidobenzoic acid head group led to a similar odd–even effect but with different dimensions or trends, which can be rationalized similarly. These results give the opportunity to create aligned conjugated polymer chains of different dimensions through self‐assembly for applications in molecular/organic electronics.
Parahydrogen‐Induced Polarization of Diethyl Ether Anesthetic
Authors: Ariyasingha Nuwandi M. , Joalland Baptiste , Younes Hassan R. , Salnikov Oleg G. , Chukanov Nikita V. , Kovtunov Kirill V. , Kovtunova Larisa M. , Bukhtiyarov Valerii I. , Koptyug Igor V. , Gelovani Juri G. , Chekmenev Eduard Y.
Published: July 2020

The growing interest in magnetic resonance imaging (MRI) for assessing regional lung function relies on the use of nuclear spin hyperpolarized gas as a contrast agent. The long gas‐phase lifetimes of hyperpolarized 129Xe make this inhalable contrast agent acceptable for clinical research today despite limitations such as high cost, low throughput of production and challenges of 129Xe imaging on clinical MRI scanners, which are normally equipped with proton detection only. We report on low‐cost and high‐throughput preparation of proton‐hyperpolarized diethyl ether, which can be potentially employed for pulmonary imaging with a nontoxic, simple, and sensitive overall strategy using proton detection commonly available on all clinical MRI scanners. Diethyl ether is hyperpolarized by pairwise parahydrogen addition to vinyl ethyl ether and characterized by 1H NMR spectroscopy. Proton polarization levels exceeding 8 % are achieved at near complete chemical conversion within seconds, causing the activation of radio amplification by stimulated emission radiation (RASER) throughout detection. Although gas‐phase T1 relaxation of hyperpolarized diethyl ether (at partial pressure of 0.5 bar) is very efficient, with T1 of ca. 1.2 second, we demonstrate that, at low magnetic fields, the use of long‐lived singlet states created via pairwise parahydrogen addition extends the relaxation decay by approximately threefold, paving the way to bioimaging applications and beyond.
N,N‐Diacylaminals as Emerging Tools in Synthesis: From Peptidomimetics to Asymmetric Catalysis
Authors: López Rosa , Palomo Claudio
Published: July 2020

N,N‐Diacylaminals are flexible molecular scaffolds that have commonly been utilized as amide surrogates in peptidomimetics. The singularities of this motif as an N‐acyl imine equivalent and as hydrogen‐bond donor have recently opened new synthetic opportunities, especially in the field of asymmetric catalysis. This concept article highlights this diverse synthetic potential and provides the elements necessary for further developments.
Shedding Light on the Origin of Solid‐State Luminescence Enhancement in Butterfly Molecules
Authors: Sánchez‐Ruiz Antonio , Rodríguez‐López Julián , Garzón‐Ruiz Andrés , Jiménez‐Pulido Sonia B. , Illán‐Cabeza Nuria A. , Navarro Amparo , García‐Martínez Joaquín C.
Published: July 2020

Different molecular strategies have been carefully evaluated to produce solid‐state luminescence enhancement (SLE) in compounds that show dark states in solution. A set of α‐phenylstyrylarene derivatives with a butterfly shape have been designed and synthesised, for the first time, with the aim of improving the solid‐state fluorescence emission of their parent styrylarene compounds. Although these butterfly molecules are not fluorescent in solution, one of them (1,2,4,5‐tetra(α‐phenylstyryl)benzene) exhibits a fluorescence quantum yield as high as 68 % in a drop‐cast sample and 31 % in its crystalline form. In contrast, 1,3,5‐tris(α‐phenylstyryl)benzene and 4,6‐bis(α‐phenylstyryl)pyrimidine do not show SLE. A range of fluorescence spectroscopy experiments and DFT calculations were carried out to unravel the origin of different photophysical behaviour of these compounds in the solid state. The results indicate that a rational strategy to control the SLE effect in luminogens depends on a delicate balance between molecular properties and inter‐/intramolecular interactions in the solid state.
Superoxide Anion Disproportionation Induced by Li+ and H+: Pathways to 1O2 Release in Li−O2 Batteries
Authors: Pierini Adriano , Brutti Sergio , Bodo Enrico
Published: July 2020

We explore the disproportionation reaction of superoxide anions in the presence of H+ and Li+ cations with high quality multiconfigurational ab‐initio methods. This reaction is of paramount importance in Li−O2 battery chemistry as it represents the source of a major degrading impurity, singlet molecular oxygen. For the first time, the thermodynamic and kinetic data of the reaction are drawn from an accurate theoretical model where the electronic structure of the reactant and products is treated at the necessary level of theory. Overall, the H+ catalyzed O2−+O2− disproportionation follows a very efficient thermodynamic and kinetic reaction path leading to neutral 3O2, 1O2 and peroxide anions. On the contrary, we have found that the Li+ catalysis promotes only the release of 3O2 whereas the 1O2 formation is energetically unfeasible at room temperature.
Comparison of Functionalized Lithium Dihydrobis(azolyl)borates with Their Corresponding Azolates as Environmentally Friendly Red Pyrotechnic Coloring Agents
Authors: Dufter Alicia M. W. , Klapötke Thomas M. , Rusan Magdalena , Schweiger Alexander , Stierstorfer Jörg
Published: July 2020

The recent awareness of the impact of strontium on health has stimulated research efforts on lithium‐based red pyrotechnic colorants. We have previously shown lithium dihydrobis(azolyl)borates to be promising candidates due to their favorable adjustment to a reductive and low‐temperature flame atmosphere. These compounds are assumed to be sufficiently stable only if the pKa values of the heterocycles are between 5 and 20. Apart from their acidities, functionalization of 1H‐tetrazole and 1H‐pyrazole with nitro or amino groups, respectively, tailors the oxygen balances of the resulting Lewis acid base adducts to enhance the fuel‐rich flame environment or to make them oxidizing agents. This work determines whether the lithium salts of dihydrobis(3‐nitropyrazol‐1‐yl)borate and dihydrobis(5‐aminotetrazol‐1‐yl)borate are suitable replacements for strontium‐containing color imparters. Furthermore, the influence of potentially green‐light‐producing boron is evaluated by comparing the emissions of the lithium borates and the corresponding lithium azolates.
Low‐Pressure Photoionization in a Dual‐Ion Funnel Injector Coupled to an Orbitrap Mass Spectrometer for Direct Analysis of Human Breath and Head‐Space Sampled Coffee Roasts
Authors: Bookmeyer Christoph , Soltwisch Jens , Röhling Ulrich , Dreisewerd Klaus
Published: July 2020

Low‐pressure photoionization (LPPI) is a versatile tool for the mass spectrometric detection of (semi‐)volatile organic compounds, (s)VOC. Here, a dual‐ion funnel MALDI/ESI ion injector was equipped with a direct‐inlet LPPI module. A radio‐frequency (RF) drive enabled the implementation of three Kr discharge lamps in a novel design optimized for efficient photoionization and undisturbed ion trajectories. Supported by expansion and collisional cooling and, optionally, dopant vapor, primarily intact radical ions and protonated molecules were generated. Molecular identification was supported by the high‐resolving power of an Orbitrap mass analyzer. In our proof‐of‐concept study, exhaled human breath and head‐space sampled coffee grounds were characterized with this high‐throughput technique. From breath, a few hundred and for the coffee roasts more than thousand distinct (s)VOC features were recorded. Principal component analysis enabled the differentiation of coffee grounds by origin and roasting protocol.
Determination of immunophenotypic aberrancies provides better assessment of peripheral blood involvement by mycosis fungoides/Sézary syndrome than quantification of CD26− or CD7− CD4+ T‐cells
Authors: Lyapichev Kirill A. , Bah Ismael , Huen Auris , Duvic Madeleine , Routbort Mark J. , Wang Wei , Jorgensen Jeffrey L. , Medeiros L. Jeffrey , Vega Francisco , Craig Fiona E. , Wang Sa A.
Published: July 2020

Background

Blood involvement by mycosis fungoides (MF)/Sézary syndrome (SS) influences prognosis and therapeutic decisions. MF/SS blood stage is currently determined by absolute CD4 + CD26− or CD4 + CD7‐cell counts, which quantification method may overestimate MF/SS by including CD26− or CD7− normal CD4+ T‐cells, or underestimate disease burden when MF/SS cells show incomplete loss of CD26 and/or CD7. Recently, through the standardization effort led by the International Clinical Cytometry Society (ICCS), recommendation was made to quantify MF/SS by enumerating immunophenotypically aberrant CD4+ T‐cells, rather than CD26− or CD7− in isolation.

Methods

We compared these two quantitation methods in 309 MF/SS patients who had blood samples analyzed by flow cytometry immunophenotyping (FCI) over a 1‐year period.

Results

Using the European Organization of Research and Treatment of Cancer (EORTC)/International Society for Cutaneous Lymphomas (ISCL) criteria, 221 (71.5%) patients had a blood stage corresponding to B0, 57 (18.4%) to B1, and 31 (10%) to B2. By FCI analysis, a total of 62 patients (20.0%) were found positive for MF/SS. Among EORTC B0 patients, 11/221 (5%) were positive by FCI (false negatives), and among EORTC Stage B1 patients, 35/57 (61%) were negative by FCI (false positives). Regarding patients positive for MF/SS cells by FCI, there was an overall excellent correlation (r = .999, p < .001) between the EORTC/ISCL method and FCI method; however, four (6.5%) patients would have an altered B stage between B0 and B1.

Conclusion

The MF/SS cell quantification method using immunophenotypic aberrancies, as recommended by the ICCS, allows to distinguish MF/SS cells from background benign T‐cells and enables for more accurate staging, especially among patients currently being considered to have B0 and B1 stage diseases.
New approaches to quantify social development in rhesus macaques (Macaca mulatta): Integrating eye tracking with traditional assessments of social behavior
Authors: Ryan Amy M. , Murai Takeshi , Lau Allison R. , Hogrefe Casey E. , McAllister A. Kimberley , Carter Cameron S. , Bauman Melissa D.
Published: July 2020

The nonhuman primate provides a sophisticated animal model system both to explore neurobiological mechanisms underlying complex behaviors and to facilitate preclinical research for neurodevelopmental and neuropsychiatric disease. A better understanding of evolutionarily conserved behaviors and brain processes between humans and nonhuman primates will be needed to successfully apply recently released NIMH guidelines (NOT‐MH‐19‐053) for conducting rigorous nonhuman primate neurobehavioral research. Here, we explore the relationship between two measures of social behavior that can be used in both humans and nonhuman primates—traditional observations of social interactions with conspecifics and eye gaze detection in response to social stimuli. Infant male rhesus macaques (Macaca mulatta) serving as controls (N = 14) for an ongoing study were observed in their social rearing groups and participated in a noninvasive, longitudinal eye‐tracking study. We found significant positive relationships between time spent viewing eyes of faces in an eye tracker and number of initiations made for social interactions with peers that is consistent with similar observations in human populations. Although future studies are needed to determine if this relationship represents species‐typical social developmental processes, these preliminary results provide a novel framework to explore the relationship between social interactions and social attention in nonhuman primate models for neurobehavioral development.
Ammonium Salt‐Catalyzed Ring‐Opening of Aryl‐Aziridines with β‐Keto Esters
Authors: Haider Victoria , Kreuzer Viktoria , Tiffner Maximilian , Spingler Bernhard , Waser Mario
Published: July 2020

We herein report an ammonium salt‐catalyzed protocol for the regioselective ring opening of aryl‐aziridines with β‐keto esters. The reaction gives access to a variety of highly functionalized target molecules with two consecutive stereogenic centers and can be rendered enantioselective (up to e.r. = 91:9) by using bifunctional chiral ammonium salt catalysts.
Palladium Catalyzed Direct Alkenylation of Dihydropyrrolo[2,1‐a]isoquinolines through the Oxidative Heck Reaction
Authors: Cui Hai‐Lei , Liu Si‐Wei , Xiao Xue
Published: July 2020

We have developed a Pd(II) catalyzed direct modification of dihydropyrrolo[2,1‐a]isoquinoline derivatives with various alkenes including acrylates, acrylamide, cyclohexenone, maleimide and styrenes. A series of highly functionalized alkenylated dihydropyrroloisoquinolines could be prepared in acceptable to good yields (up to 98 %) through oxidative Heck coupling.
Microflow system promotes acetaminophen crystal nucleation
Authors: Nishigaki Akari , Maruyama Mihoko , Numata Munenori , Kanzaki Chisako , Tanaka Shun‐Ichi , Yoshikawa Hiroshi Y. , Imanishi Masayuki , Yoshimura Masashi , Mori Yusuke , Takano Kazufumi
Published: July 2020

It is known that interfaces have various impacts on crystallization from a solution. Here, we describe crystallization of acetaminophen using a microflow channel, in which two liquids meet and form a liquid–liquid interface due to laminar flow, resulting in uniform mixing of solvents on the molecular scale. In the anti‐solvent method, the microflow mixing promoted the crystallization more than bulk mixing. Furthermore, increased flow rate encouraged crystal formation, and a metastable form appeared under a certain flow condition. This means that interface management by the microchannel could be a beneficial tool for crystallization and polymorph control.
A reduced‐order electrochemical model for coupled prediction of state of charge and state of health of lithium ion batteries under constant current‐constant voltage charging conditions
Authors: Dingari Naga Neehar , Mynam Mahesh , Rai Beena
Published: July 2020

Accurate and fast prediction of the remaining useful life of lithium (Li) ion batteries is an important requirement for successful electrification of automobiles. Consequently, there is a growing interest in the development of reduced‐order models. The existing reduced‐order electrochemical models can be used to predict battery performance (state of charge [SoC], terminal voltage) when the current through the battery is known a priori. Therefore these models cannot be used for studying the constant voltage (CV) mode of the constant current‐CV (CC‐CV) charging protocol, which is a common battery charging mechanism. In this work, we propose a reduced‐order electrochemical model to estimate the battery SoC under CC‐CV charging conditions, along with an analytical expression to approximate the CV mode charging time. We further propose a framework that accounts for the influence of the battery state of health (SoH) on the battery SoC during an operating cycle and vice‐versa. The proposed framework for estimating the battery SoC and SoH in a coupled manner shows good comparison with a first principles electrochemical model for CC‐CV charging conditions. This model can be used to study battery ageing and it can find applications in real‐time state estimation, charge protocol optimization, and battery design.
Sense of external agency is sustained by multisensory functional integration in the somatosensory cortex
Authors: Piras Federica , Vecchio Daniela , Ciullo Valentina , Gili Tommaso , Banaj Nerisa , Piras Fabrizio , Spalletta Gianfranco
Published: July 2020

“Sense of agency” (SoA), the feeling of control for events caused by one's own actions, is deceived by visuomotor incongruence. Sensorimotor networks are implicated in SoA, however little evidence exists on brain functionality during agency processing. Concurrently, it has been suggested that the brain's intrinsic resting‐state (rs) activity has a preliminary influence on processing of agency cues. Here, we investigated the relation between performance in an agency attribution task and functional interactions among brain regions as derived by network analysis of rs functional magnetic resonance imaging. The action‐effect delay was adaptively increased (range 90–1,620 ms) and behavioral measures correlated to indices of cognitive processes and appraised self‐concepts. They were then regressed on local metrics of rs brain functional connectivity as to isolate the core areas enabling self‐agency. Across subjects, the time window for self‐agency was 90–625 ms, while the action‐effect integration was impacted by self‐evaluated personality traits. Neurally, the brain intrinsic organization sustaining consistency in self‐agency attribution was characterized by high connectiveness in the secondary visual cortex, and regional segregation in the primary somatosensory area. Decreased connectiveness in the secondary visual area, regional segregation in the superior parietal lobule, and information control within a primary visual cortex‐frontal eye fields network sustained self‐agency over long‐delayed effects. We thus demonstrate that self‐agency is grounded on the intrinsic mode of brain function designed to organize information for visuomotor integration. Our observation is relevant for current models of psychopathology in clinical conditions in which both rs activity and sense of agency are altered.
Exploring the changes of physicians' behaviour toward informal payment based on Health Transformation Plan in Iran: A qualitative study
Authors: Sakha Minoo Alipouri , Zahirian Moghadam Telma , Ghobadi Hassan , Zandian Hamed
Published: July 2020

By implementation of the Health Transformation Plan (HTP), a revised tariff system for healthcare services was executed in Iran. This study explores the changes in physicians' behaviour in facing informal payment (IP) based on HTP implementation in Iran. We conducted in‐depth semi‐structured interviews with 15 purposefully selected physicians and policy makers to explore the changes (positive, negative and no) in physicians' behaviours with and without the implementation of HTP. The interviews were conducted individually and face to face. The conventional content analysis for data analysis by MAXQDA ver.10 was used. Based on the results, regardless of the HTP implemented, market competitiveness could control physicians' demand for IP. However, unreal tariffs, irregular payments, inflation, expensive healthcare and comparing income with other occupations increase physicians' demand for IP as negative behaviour. This study explored three patterns of physicians' behavioural change because of HTP implementation: 1—positive behavioural change with four factors; 2—negative behavioural changes with two factors; and 3—no behavioural change with four factors. Various factors influenced physicians' behaviour towards IP with and without the HTP. To combat IP more efficiently, we recommend strengthening the HTP's positive interventions, compensation of physicians' target income, enhancing supervision, reducing the gap among various medical specialities and taking a systematic approach with law offenders.
Too much tenure? Nonlinear effects and moderated influences of unit‐level tenure and labor productivity
Authors: Subramony Mahesh , Chadwick Clint
Published: July 2020

This study contributes to human capital resource literature by providing a robust and theoretically grounded examination of the relationship between unit‐level tenure and performance. We (a) posit and test the notion of a positive nonlinear relationship between aggregate tenure and labor productivity and (b) expand the current conceptualizations of unit‐level tenure to examine the joint and interactive effects of aggregate tenure and tenure dispersion on labor productivity. Utilizing time‐lagged data collected from a field‐sample of 514 college bookstores, we report findings suggesting that unit‐level aggregate tenure has a positive but nonlinear relationship with labor productivity such that increasing tenure beyond an optimum point produces diminishing returns. These results are replicated in a second study conducted with a cross‐sectional sample of 727 service organizations in the United States. Further, our findings indicate that tenure dispersion is negatively related to labor productivity but positively moderates the relationship between aggregated tenure and labor productivity.