bluuebunny/crossref_metadata_2025 huggingface dataset:
Pain Over Two Years After Start of Biologic Versus Conventional Combination Treatment in Early Rheumatoid Arthritis: Results From a Swedish Randomized Controlled Trial
Authors: Olofsson Tor , Wallman Johan K. , Jöud Anna , Schelin Maria E. C. , Ernestam Sofia , van Vollenhoven Ronald , Saevarsdottir Saedis , Lampa Jon
Published: May 2020

Objective

To compare the pain course between methotrexate (MTX)‐refractory early rheumatoid arthritis (RA) patients randomized to infliximab (IFX) versus sulfasalazine (SSZ) plus hydroxychloroquine (HCQ).

Methods

The randomized, controlled, open‐label Swedish Pharmacotherapy (SWEFOT) trial enrolled new‐onset RA patients from October 2002 to December 2005. After 3 months of receiving MTX, patients not reaching low disease activity (Disease Activity Score in 28 joints score ≤3.2) were randomized to adding IFX (n = 128) or SSZ plus HCQ (n = 130) and followed for 21 months. Here, outcomes included area under the curve (AUC) for visual analog scale (VAS) scores for pain, unacceptable pain (VAS pain score >40 mm [range 0–100]), and unacceptable pain despite inflammation control (refractory pain; VAS pain score >40 plus C‐reactive protein level <10 mg/liter). Between‐group differences were analyzed with multivariate regression models.

Results

Overall, 50% of randomized patients (n = 258) in the crude setting reported unacceptable pain at randomization, declining to 29% at 21 months (P < 0.001), when refractory pain constituted 82% of all unacceptable pain. Comparing randomized arms (intent‐to‐treat analysis), the AUC for VAS pain was lower in the MTX plus IFX group (P = 0.01), and at 21 months, 32% of patients receiving MTX plus IFX and 45% receiving MTX plus SSZ plus HCQ had unacceptable pain (adjusted relative risk 0.68 [95% confidence interval 0.51, 0.90]; P = 0.008). Regarding refractory pain, no between‐group differences were observed.

Conclusion

Despite active combination treatment, almost one‐third of new‐onset RA patients reported unacceptable pain after 21 months, and refractory pain constituted more than 4/5 of this pain load. Adding IFX versus SSZ plus HCQ to MTX reduced both cumulative pain and unacceptable pain at 21 months, suggesting less long‐term pain for the biologic therapy. These results display insufficient effects of current treatment strategies on inflammation‐independent pain components, warranting alternative approaches in affected patients.
Additive Manufacturing of Tailored Macroporous Ceramic Structures for High‐Temperature Applications
Authors: Sobhani Sadaf , Allan Shawn , Muhunthan Priyanka , Boigne Emeric , Ihme Matthias
Published: May 2020

Macroporous ceramic materials are ubiquitous in numerous energy‐conversion and thermal‐management systems. The morphology and material composition influence the effective thermophysical properties of macroporous ceramic structures and interphase transport in interactions with the working fluid. Therefore, tailoring these properties can enable significant performance enhancements by modulating thermal transport, reactivity, and stability. However, conventional ceramic‐matrix fabrication techniques limit the ability for tailoring the porous structure and optimizing the performance of these systems, such as by introducing anisotropic morphologies, pore‐size gradations, and variations in pore connectivity and material properties. Herein, an integrated framework is proposed for enabling the design, optimization, and fabrication of tailored ceramic porous structures by combining computational modeling, mathematically defined surfaces, and lithography‐based additive manufacturing. The benefits of pore‐structure tailoring are illustrated experimentally for interstitial combustion in a porous‐media burner operating with a smoothly graded matrix structure. In addition, a remarkable range of achievable thermal conductivities for a single material is demonstrated with tuning of the fabrication process, thus providing unique opportunities for modulating thermal transport properties of porous‐ceramic structures.
Oxygen Vacancy Modulation of Bimetallic Oxynitride Anodes toward Advanced Li‐Ion Capacitors
Authors: Wang Shouzhi , Li Lili , He Weidong , Shao Yongliang , Li Yanlu , Wu Yongzhong , Hao Xiaopeng
Published: May 2020

Binary metal oxides (such as NiCo2O4) are regarded as attractive electrode materials for advanced energy storage devices since they offer more electrochemical activity and higher capacity than monometal oxide. However, the volume expansion and low electronic conductivity are the main bottleneck seriously hindering their application. To overcome these barriers, a novel strategy that introduces a bimetallic oxynitride layer (NiCoON) with oxygen vacancy to the surface of NiCo2O4 nanowires as an anode for Li‐ion capacitors (LICs) is proposed. The oxygen vacancy on the surface and the modulation of multiple valence states are investigated by the electron paramagnetic resonance, X‐ray photoelectron spectroscopy characterization, and first‐principles calculation. Benefiting from the merits of substantially improved electrical conductivity and increased concentration of active sites, the optimized NiCoON electrode delivers remarkable capacity (1855 mAh g−1 at 0.2 A g−1) and rate performance. The LIC device assembled by NiCoON anodes and N‐doped carbon nanowire cathodes delivers excellent rate capability, high energy density (148.5 Wh kg−1), and outstanding power density (30 kW kg−1). This study provides a new pathway for developing bimetallic oxides with an improved performance in electrochemical energy storage, conversion fields, and beyond.
Efficient Blue Perovskite Light‐Emitting Diodes Boosted by 2D/3D Energy Cascade Channels
Authors: Zhang Fengjuan , Cai Bo , Song Jizhong , Han Boning , Zhang Baisong , Zeng Haibo
Published: May 2020

Lead halide perovskite, as an emerging semiconductor, provides a fire‐new opportunity for high‐definition display and solid‐state lighting. Earthshaking improvements are implemented in green, red, and near‐infrared perovskite light‐emitting diodes (PeLEDs). However, blue PeLEDs are still far behind in performance, which restricts the development of PeLEDs in practical applications. Herein, a facile energy cascade channel strategy via one‐step self‐organized and controllable 2D/3D perovskite preparation by introducing guanidine hydrobromide (GABr) is developed that greatly improves the efficiency of blue PeLEDs. The 2D/3D perovskite structure boosts the energy cascade to induce energy transfer from the wide into the narrow bandgap domains and inhibit free charge diffusion, which increases the density of electrons and holes, and enhances the radiative recombination. Profiting from this energy cascade channels, the external quantum efficiency of blue PeLEDs, emitting at 492 nm, is considerably enhanced from 1.5% of initial blue device to 8.2%. In addition, device operating stability under ambient conditions is also improved by 2.6‐fold. The one‐step self‐organized 2D/3D hybrid perovskites induced by GABr pave a new and simple route toward high‐performance blue emission PeLEDs.
Spin‐Selective Full‐Dimensional Manipulation of Optical Waves with Chiral Mirror
Authors: Li Zhancheng , Liu Wenwei , Cheng Hua , Choi Duk‐Yong , Chen Shuqi , Tian Jianguo
Published: May 2020

Realizing arbitrary manipulation of optical waves, which still remains a challenge, plays a key role in the implementation of optical devices with on‐demand functionalities. However, it is hard to independently manipulate multiple dimensions of optical waves because the optical dimensions are basically associated with each other when adjusting the optical response of the devices. Here, the concise design principle of a chiral mirror is utilized to realize the full‐dimensional independent manipulation of circular‐polarized waves. By simply changing three structural variables of the chiral mirror, the proposed design principle can arbitrarily and independently empower the spin‐selective manipulation of amplitude, phase, and operation wavelength of circular‐polarized waves with a large modulation depth. This approach provides a simple solution for the realization of spin‐selective full‐dimensional manipulation of optical waves and shows ample application possibilities in the areas of optical encryption, imaging, and detection.
Concurrently Approaching Volumetric and Specific Capacity Limits of Lithium Battery Cathodes via Conformal Pickering Emulsion Graphene Coatings
Authors: Park Kyu‐Young , Lim Jin‐Myoung , Luu Norman S. , Downing Julia R. , Wallace Shay G. , Chaney Lindsay E. , Yoo Hocheon , Hyun Woo Jin , Kim Hyeong‐U , Hersam Mark C.
Published: May 2020

To achieve the high energy densities demanded by emerging technologies, lithium battery electrodes need to approach the volumetric and specific capacity limits of their electrochemically active constituents, which requires minimization of the inactive components of the electrode. However, a reduction in the percentage of inactive conductive additives limits charge transport within the battery electrode, which results in compromised electrochemical performance. Here, an electrode design that achieves efficient electron and lithium‐ion transport kinetics at exceptionally low conductive additive levels and industrially relevant active material areal loadings is introduced. Using a scalable Pickering emulsion approach, Ni‐rich LiNi0.8Co0.15Al0.05O2 (NCA) cathode powders are conformally coated using only 0.5 wt% of solution‐processed graphene, resulting in an electrical conductivity that is comparable to 5 wt% carbon black. Moreover, the conformal graphene coating mitigates degradation at the cathode surface, thus providing improved electrochemical cycle life. The morphology of the electrodes also facilitates rapid lithium‐ion transport kinetics, which provides superlative rate capability. Overall, this electrode design concurrently approaches theoretical volumetric and specific capacity limits without tradeoffs in cycle life, rate capability, or active material areal loading.
Cycling a Lithium Metal Anode at 90 °C in a Liquid Electrolyte
Authors: Hou Li‐Peng , Zhang Xue‐Qiang , Li Bo‐Quan , Zhang Qiang
Published: May 2020

Stable operation at elevated temperature is necessary for lithium metal anode. However, Li metal anode generally has poor performance and safety concerns at high temperature (>55 °C) owing to the thermal instability of the electrolyte and solid electrolyte interphase in a routine liquid electrolyte. Herein a Li metal anode working at an elevated temperature (90 °C) is demonstrated in a thermotolerant electrolyte. In a Li|LiFePO4battery working at 90 °C, the anode undergoes 100 cycles compared with 10 cycles in a practical carbonate electrolyte. During the formation of the solid electrolyte interphase, independent and incomplete decomposition of Li salts and solvents aggravate. Some unstable intermediates emerge at 90 °C, degenerating the uniformity of Li deposition. This work not only demonstrates a working Li metal anode at 90 °C, but also provides fundamental understanding of solid electrolyte interphase and Li deposition at elevated temperature for rechargeable batteries.
Reactions between Diazo Compounds and Hypervalent Iodine(III) Reagents
Authors: Zhao Rong , Shi Lei
Published: May 2020

Site‐selective “cut and sew” transformations employing diazo compounds and hypervalent iodine(III) compounds involve the departure of leaving groups, a “cut” process, followed by a reorganization of the fragments by bond formation, a “sew” process. Bearing controllable cleavage sites, diazo compounds and hypervalent iodine(III) compounds play a critical role as versatile reagents in a wide range of organic transformations because their excellent nucleofugality allows for a large number of unusual reactions to occur. In recent years, the combination of diazo compounds and hypervalent iodine(III) reagents has emerged as a promising tool for developing new and valuable approaches, and has met considerable success. In this Minireview, this combination is systematically illustrated with recent advances in the field, with the aim of elaborating the synthetic utility and potential of this concept as a powerful strategy in organic synthesis.
A Macrocycle Based on a Heptagon‐Containing Hexa‐peri‐hexabenzocoronene
Authors: Jiménez Vicente G. , David Arthur H. G. , Cuerva Juan M. , Blanco Victor , Campaña Araceli G.
Published: May 2020

A cyclophane is reported incorporating two units of a heptagon‐containing extended polycyclic aromatic hydrocarbon (PAH) analogue of the hexa‐peri‐hexabenzocoronene (HBC) moiety (hept‐HBC). This cyclophane represents a new class of macrocyclic structures that incorporate for the first time seven‐membered rings within extended PAH frameworks. The saddle curvature of the hept‐HBC macrocycle units induced by the presence of the nonhexagonal ring along with the flexible alkyl linkers generate a cavity with shape complementarity and appropriate size to enable π interactions with fullerenes. Therefore, the cyclophane forms host–guest complexes with C60 and C70 with estimated binding constants of Ka=420±2 m−1 and Ka=(6.49±0.23)×103 m−1, respectively. As a result, the macrocycle can selectively bind C70 in the presence of an excess of a mixture of C60 and C70.
Beute für das Proteasom: Gezielter Proteinabbau aus medizinalchemischer Perspektive
Authors: Luh Laura M. , Scheib Ulrike , Juenemann Katrin , Wortmann Lars , Brands Michael , Cromm Philipp M.
Published: May 2020

Der gezielte Proteinabbau (targeted protein degradation, TPD), die Fähigkeit, das Schicksal eines Proteins durch Auslösen seines Abbaus auf hoch selektive und effiziente Weise kontrollieren zu können, hat in den letzten Jahrzehnten für ein enormes Interesse in der chemischen Biologie und der Wirkstoffentwicklung gesorgt. Führende Konzepte im TPD‐Gebiet sind der niedermolekular‐induzierte Proteinabbau mittels “Molekularer Kleber” (molecular glue) und PROTACs (proteolysis targeting chimeras), die den Weg für die Erweiterung des wirkstofftauglichen (druggable) Strukturraums ebnen und ein neues Paradigma der Wirkstoffentwicklung erschaffen haben. Zudem wurde eine Fülle neuer Techniken entwickelt, um die zellulären Proteinlevel zu modulieren und zu kontrollieren, was ein besseres Verständnis der Proteinfunktionen sowie die Erkennung und Verifizierung neuer therapeutischer Targets ermöglicht. Dieser Artikel bietet einen umfassenden Überblick über chemisch‐biologische Techniken zur Induktion von TPD. Er erläutert die Stärken und Schwächen dieser Methoden im Kontext der Wirkstoffentwicklung und erörtert ihr zukünftiges Potenzial aus der Perspektive eines Medizinalchemikers.
Studying Natural Buckyballs and Buckybowls in Fossil Materials
Authors: Farmani Zahra , Vetere Alessandro , Poidevin Corentin , Auer Alexander A. , Schrader Wolfgang
Published: May 2020

Buckyballs (fullerenes) were first reported over 30 years ago, but still little is known regarding their natural occurrence, since they have so far only been found at sites of high‐energy incidents, such as lightning strikes or meteor impacts, but have not been reported in low‐energy materials like fossil fuels. Using ultrahigh‐resolution mass spectrometry, a wide range of fullerenes from C30 to C114 was detected in the asphaltene fraction of a heavy crude oil, together with their building blocks of C10nH10 stoichiometry. High‐level DLPNO‐CCSD(T) calculations corroborate their stability as spherical and hemispherical species. Interestingly, the maximum intensity of the fullerenes was found at C40 instead of the major fullerene C60. Hence, experimental evidence supported by calculations show the existence of not only buckyballs but also buckybowls as 3‐dimensional polyaromatic compounds in fossil materials.
Observation of Transition‐Metal–Boron Triple Bonds in IrB2O− and ReB2O−
Authors: Chen Teng‐Teng , Cheung Ling Fung , Chen Wei‐Jia , Cavanagh Joseph , Wang Lai‐Sheng
Published: May 2020

Multiple bonds between boron and transition metals are known in many borylene (:BR) complexes via metal dπ→BR back‐donation, despite the electron deficiency of boron. An electron‐precise metal–boron triple bond was first observed in BiB2O− [Bi≡B−B≡O]− in which both boron atoms can be viewed as sp‐hybridized and the [B−BO]− fragment is isoelectronic to a carbyne (CR). To search for the first electron‐precise transition‐metal‐boron triple‐bond species, we have produced IrB2O− and ReB2O− and investigated them by photoelectron spectroscopy and quantum‐chemical calculations. The results allow to elucidate the structures and bonding in the two clusters. We find IrB2O− has a closed‐shell bent structure (Cs, 1A′) with BO− coordinated to an Ir≡B unit, (−OB)Ir≡B, whereas ReB2O− is linear (C∞v, 3Σ−) with an electron‐precise Re≡B triple bond, [Re≡B−B≡O]−. The results suggest the intriguing possibility of synthesizing compounds with electron‐precise M≡B triple bonds analogous to classical carbyne systems.
Prey for the Proteasome: Targeted Protein Degradation—A Medicinal Chemist's Perspective
Authors: Luh Laura M. , Scheib Ulrike , Juenemann Katrin , Wortmann Lars , Brands Michael , Cromm Philipp M.
Published: May 2020

Targeted protein degradation (TPD), the ability to control a proteins fate by triggering its degradation in a highly selective and effective manner, has created tremendous excitement in chemical biology and drug discovery within the past decades. The TPD field is spearheaded by small molecule induced protein degradation with molecular glues and proteolysis targeting chimeras (PROTACs) paving the way to expand the druggable space and to create a new paradigm in drug discovery. However, besides the therapeutic angle of TPD a plethora of novel techniques to modulate and control protein levels have been developed. This enables chemical biologists to better understand protein function and to discover and verify new therapeutic targets. This Review gives a comprehensive overview of chemical biology techniques inducing TPD. It explains the strengths and weaknesses of these methods in the context of drug discovery and discusses their future potential from a medicinal chemist's perspective.
A Heteroleptic Dirhodium Catalyst for Asymmetric Cyclopropanation with α‐Stannyl α‐Diazoacetate. “Stereoretentive” Stille Coupling with Formation of Chiral Quarternary Carbon Centers
Authors: Caló Fabio P. , Fürstner Alois
Published: May 2020

The heteroleptic dirhodium paddlewheel catalyst 7 with a chiral carboxylate/acetamidate ligand sphere is uniquely effective in asymmetric [2+1] cycloadditions with α‐diazo‐α‐trimethylstannyl (silyl, germyl) acetate. Originally discovered as a trace impurity in a sample of the homoleptic parent complex [Rh2((R)‐TPCP)4] (5), it is shown that the protic acetamidate ligand is quintessential for rendering 7 highly enantioselective. The ‐NH group is thought to lock the ensuing metal carbene in place via interligand hydrogen bonding. The resulting stannylated cyclopropanes undergo “stereoretentive” cross coupling, which shows for the first time that even chiral quarternary carbon centers can be made by the Stille–Migita reaction.
Emissive Metallacycle‐Crosslinked Supramolecular Networks with Tunable Crosslinking Densities for Bacterial Imaging and Killing
Authors: Jeyakkumar Ponmani , Liang Yongping , Guo Mengying , Lu Shuai , Xu Donghua , Li Xiaopeng , Guo Baolin , He Gang , Chu Dake , Zhang Mingming
Published: May 2020

The chemical structures and topologies of the crosslinks in supramolecular networks play a crucial role in their properties and functions. Herein, the preparation of a type of poly(N‐isopropylacrylamide) (PNIPAAM)‐based supramolecular networks crosslinked by emissive hexagonal metallacycles is presented. The topological connections in these networks greatly affect their properties, as evidenced by their differences in absorption, emission, lower critical solution temperature, and modulus along with the variation of crosslinking densities. The integration of PNIPAAM and metallacycles in the networks benefits them improved bioavailability, making them serve as reagents for bacterial imaging and killing. This study provides a strategy to prepare cavity‐crosslinked polymer networks for antibacterial applications.
Enantiomeric Discrimination by Surface‐Enhanced Raman Scattering–Chiral Anisotropy of Chiral Nanostructured Gold Films
Authors: Liu Zexi , Ai Jing , Kumar Prashant , You Enming , Zhou Xiong , Liu Xi , Tian Zhongqun , Bouř Petr , Duan Yingying , Han Lu , Kotov Nicholas A. , Ding Songyuan , Che Shunai
Published: May 2020

A surface‐enhanced Raman scattering‐chiral anisotropy (SERS‐ChA) effect is reported that combines chiral discrimination and surface Raman scattering enhancement on chiral nanostructured Au films (CNAFs) equipped in the normal Raman scattering Spectrometer. The CNAFs provided remarkably higher enhancement factors of Raman scattering (EFs) for particular enantiomers, and the SERS intensity was proportional to the enantiomeric excesses (ee) values. Except for molecules with mesomeric species, all of the tested enantiomers exhibited high SERS‐ChA asymmetry factors (g), ranging between 1.34 and 1.99 regardless of polarities, sizes, chromophores, concentrations and ee. The effect might be attributed to selective resonance coupling between the induced electric and magnetic dipoles associated with enantiomers and chiral plasmonic modes of CNAFs.
Two new micro‐isostructural metal–organic polymers based on mixed‐ligand copper(I): Structures and selective sensing of nitro explosives in water
Authors: Gholivand Khodayar , K. Tizhoush Samaneh , Kozakiewicz Anna
Published: May 2020

Two new one‐dimensional metal–organic polymers (MOPs) {[Cu(L)(PPh2Py)·I2]·CH3Cl}n (I) and {[Cu(L)(PPh2Py)·Br2]·CH3Cl}n (II) (L = (1E,2E)‐1,2‐bis(pyridine‐4‐ylmethylene)hydrazine) (4‐bpmh)) have been synthesized and elucidated by single crystal X‐ray diffraction. The results of X‐ray diffraction analysis unambiguously revealed that the two polymers are isostructural with the major intermolecular CH⋯π and π⋯π interactions. Microstructures of these polymers were also synthesized using a sonochemical method in different concentrations and reaction times. Field emission scanning electron microscopy, powder X‐ray diffraction, thermogravimetric analysis and IR spectroscopy were applied to fully characterize these compounds. The photoluminescent properties of microrod MOPs were also evaluated to add to our understanding of their potential ability for nitro compound sensing. These experiments showed that MOPs I and II are good luminescence sensors for detection of nitro explosives in aqueous media. The probes maintained their high sensitivity and selectivity for 4‐nitrophenol (4‐NP). The energy transfer process accompanied by electrostatic interactions of 4‐NP with these MOPs can be considered as an influential reason for the selectivity of 4‐NP. The competitive study of the quenching process has a6lso shown superior operation with microparticles compared with bulky polymers. These results indicate that this method may be useful to synthesize luminescent materials possessing good sensing properties.
A mechanically robust copper mesh with switchable wettability and antibacterial activity for selective oil–water separation
Authors: Hou Yatong , Wang Bo , Zhang Tingting , Pei Jiarong , Li Qiurong , Zhang Tao
Published: May 2020

With the continuous improvement in living standards, the discharge of oily sewage in daily life and industry has gradually increased, causing considerable damage to the environment and also great inconvenience to people. Traditional treatment methods cannot meet the increasing demand for sewage treatment, so more efficient treatment methods need to be studied. Research on oil–water separation materials is gradually becoming intelligent, but most of these intelligent materials cannot solve the problem of bacterial growth on the surface, new antibacterial and hydrophobic materials need to be studied. Here, an inexpensive and simple method is presented to prepare an antibacterial copper mesh with pH‐responsive wettability between hydrophilic and hydrophobic. First, a copper mesh with a rough surface was prepared by an oxidation method, and then the oxidized copper mesh was immersed in the prepared coating solution of stearate (SA)‐TiO2 to obtain a superhydrophobic copper mesh. Scanning electron microscopy analysis showed that the modified copper mesh changed from the original smooth surface to a rough surface covered with needle‐like nano‐oxide wires. The SA‐TiO2‐coated copper mesh (STCM) has good separation efficiency (about 97%) and separation flux (about 1.1 × 105 L·m−2·h−1) for the immiscible oil–water mixture, the separation efficiency remained basically unchanged (about 97%) after 15 separation cycles, and the wettability of this can be changed by soaking in an alkaline solution at a specific pH (from 12 to 14). In addition, the prepared STCM showed good antibacterial properties against Staphylococcus aureus and Escherichia coli. This preparation strategy of STCM provides a low‐cost and facile method for wastewater treatment in practical applications.
Synthesis, reactivity,in vitroboron neutron capture therapy assay, and molecular docking of fluorocyclocarboxyboranylamine
Authors: Zhu Yinghuai , Cai Jianghong , Zheng Chong , Narayan S Hosmane , Masao Takagaki
Published: May 2020

The one‐pot reaction of Me3NBH2CN with Et3O+BF4−followed by addition of BF3·Et2O and water produces a trimethylamine derivative of fluorocyclocarboxyboranylamine, Me3NBH2C(O2BF2NH2) (1) in 36.0% yield. Compound1undergoes exchange reaction between the exo‐Me3N moiety and piperidine or pyridine to produce the corresponding piperidine‐substituted fluorocyclocarboxyboranylamine (2) or pyridine‐substituted fluorocyclocarboxyboranylamine (3) in 51.2% or 42.4% yields, respectively. The new compounds were characterized by1H,13C,11B, and19F nuclear magnetic resonance spectroscopy; Fourier‐transform infrared spectroscopy; and elemental analyses and the crystal structure of1was determined to confirm its molecular geometry. Thein vitrokilling effects of1, along with its toxicity measurements and molecular docking interactions with matrix metalloproteinases showed a potential promise of such species as both boron neutron capture therapy and boron neutron capture synovectomy agents in the treatment of tumors and rheumatoid arthritis, respectively, in the presence of slow neutrons.
“The dearest of our possessions”: Applying Floridi's information privacy concept in models of information behavior and information literacy
Authors: Bawden David , Robinson Lyn
Published: May 2020

This conceptual article argues for the value of an approach to privacy in the digital information environment informed by Luciano Floridi's philosophy of information and information ethics. This approach involves achieving informational privacy, through the features of anonymity and obscurity, through an optimal balance of ontological frictions. This approach may be used to modify models for information behavior and for information literacy, giving them a fuller and more effective coverage of privacy issues in the infosphere. For information behavior, the Information Seeking and Communication Model and the Information Grounds conception are most appropriate for this purpose. For information literacy, the metaliteracy model, using a modification a privacy literacy framework, is most suitable.
Sustainable environmental practices and financial performance: Evidence from listed small and medium‐sized enterprise in the United Kingdom
Authors: Boakye Danquah Jeff , TIngbani Ishmael , Ahinful Gabriel , Damoah Isaac , Tauringana Venancio
Published: May 2020

In this article, we investigate the financial implication of sustainable environmental practices on UK small and medium‐sized enterprises (SMEs)–traded firms. Existing literature indicates that there is a direct relationship between sustainable environmental practices and financial performance. However, studies looking at this relationship have focused mainly on large firms with little attention paid to SMEs. Further, those looking at environmental and financial performance relationships have often used a single measure of performance in their studies. This study bridges these research gaps by focusing on listed SMEs in the United Kingdom using multiple measures of sustainable environmental policy indices on a panel of 201 SMEs on the Alternative Investment Market from 2011 to 2016. Evidence from our panel data analysis suggests significant and a nonlinear (concave) relationship between sustainable environmental practices and firms' financial performance. Specifically, energy efficiency practices, greenhouse gases, material, and resource efficiency revealed an inverted U‐shaped relationship with financial performance. The results will offer guidance to management in terms of allocating resources to sustainable environmental practices investment.
Anatomical study of the pial arterial network in human spinal cords
Authors: Rojas Santiago , Ortega Marisa , Rodríguez‐Baeza Alfonso
Published: May 2020

Introduction

Multiple collaterals originate from three main longitudinal vessels to perfuse the human spinal cord. Only a few classic studies published in the last century have investigated these collaterals. The current work proposes a possible classification of these vessels and analyzes their relative abundance along spinal cord segments.

Materials and Methods

Human spinal cords (n = 30) from male and female cadavers were injected with colored latex through the vertebral, ascending cervical, costocervical trunk and segmental arteries and then fixed in formaldehyde solution. Afterwards, spinal vessels were dissected and the relative abundances of each type of collateral were quantified and compared between different spinal cord segments.

Results

Collaterals of the anterior longitudinal pathway can be classified as central arteries and arteries for the anterior and lateral columns. Collaterals for the anterior column can be classified into two types: anteromedial and anterolateral. Arteries for the lateral column can be classified, according to their relationship with the dentate ligament, as either preligamentous or post‐ligamentous. The collaterals of posterior longitudinal pathways can be divided between those for the posterior and those for the lateral column. In turn, the arteries for the posterior column can be classified into three types: median posterior, posteromedial and posterolateral. The collaterals for the lateral column were also classified as either pre‐ or post‐ligamentous.

Conclusion

The relative abundance of the various types of collateral and anastomoses between longitudinal pathways was inhomogeneous along the spinal cord, with several statistically significant differences observed between spinal segments.
Conformational Selection as the Driving Force of Amyloid β Chiral Inactivation
Authors: Raskatov Jevgenij A.
Published: May 2020

We recently introduced amyloid β chiral inactivation (Aβ‐CI) as a molecular approach that uses mirror‐image peptides to chaperone the natural Aβ stereoisomer into a less toxic state. The oligomer‐to‐fibril conversion mechanism remains the subject of active research. Perhaps the most striking feature of Aβ‐CI is the virtual obliteration of the incubation/induction phase that is so characteristic of Aβ fibril formation kinetics. This qualitative change is indicative of the distinct mechanistic pathway Aβ‐CI operates through. The current working model of Aβ‐CI invokes the formation of “rippled” cross‐β sheets, in which alternating l‐ and d‐peptide strands form periodic networks. However, the assumption of rippled cross‐β sheets does not per se explain the dramatic changes in reaction kinetics upon mixing of Aβ enantiomers. Herein, it is shown by DFT computational methods that the individual peptide strands in rippled cross‐β networks are less conformationally strained than their pleated counterparts. This means that the adoption of fibril‐seeding conformations is more probable for rippled cross‐β. Conformational selection is thus suggested as the mechanistic rationale for the acceleration of fibril formation upon Aβ‐CI.
Thiol‐Disulfide Exchange Reaction Promoted Highly Efficient Cellular Uptake of Pyridyl Disulfide Appended Nonionic Polymers
Authors: Bej Raju , Ghosh Arijit , Sarkar Jayita , Das Benu Brata , Ghosh Suhrit
Published: May 2020

The intracellular transport of molecules, macromolecules or materials is a key step in probing cellular structure and function, as well as regulating a plethora of physical and chemical events for treating disease. This communication reveals direct cellular uptake of pyridyl‐disulfide (Py−Ds)‐conjugated nonionic and biocompatible macromolecules with the aid of rapid exchange of the highly reactive Py−Ds groups with exofacial cell‐surface thiols. Confocal microscopy and flow cytometry analysis confirmed highly efficient cellular uptake of Py−Ds‐appended polymers (>50 % in 15 min) by avoiding lysosome as a consequence of thiol‐disulfide exchange in the cell surface. In contrast, a control polymer lacking the Py−Ds group followed caveolae‐mediated endocytosis. Other control polymers containing either the pyridine group (but not disulfide) or the disulfide group (but not pyridine) revealed significantly low cellular uptake, and thus essential role of the highly reactive Py−Ds group was established beyond doubt.
Comparison of acute recoil after valve deployment and after post‐dilation in patients undergoing transfemoral‐transcatheter aortic valve replacement with SAPIEN‐3 valve
Authors: Sammour Yasser , Kadri Amer N. , Gajulapalli Rama Dilip , Kaur Manpreet , Bazarbashi Najdat , Banerjee Kinjal , Karrthik Antonette , Dhaliwal Kamalpreet , Burns Daniel , Yun James , Krishnaswamy Amar , Kapadia Samir R.
Published: May 2020

Background

Transcatheter aortic valves are prone to acute recoil similar to the metal‐based coronary stents. However, it is not clear if recoil remains a factor only after the initial valve deployment or also after post‐dilation.

Methods

We conducted a retrospective observational study of patients who underwent transfemoral transcatheter aortic valve replacement (TAVR) with SAPIEN‐3 valve. Acute recoil at the upper, central, and lower levels of the valve was calculated in both anteroposterior right anterior oblique (RAO) and lateral left anterior oblique (LAO) views after initial deployment as well as after post‐dilation. The average recoil of the RAO and LAO views was also calculated and described as RAO/LAO.

Results

The acute recoil in the RAO/LAO views (mean ± SD) was 3.9 ± 1.1% after valve deployment in the whole study population (n = 257). Among the subset of patients who required post‐dilation (n = 133), the mean acute recoil in the RAO/LAO views was found to be greater after initial valve deployment as compared with after post‐dilation (3.8 ± 1.1% vs. 3.0 ± 0.9%; p < .001). Further, acute recoil was significantly greater in the RAO view than the LAO view and at the central level of the prosthesis as compared with the upper and lower levels. Those findings were consistent after initial deployment as well as after post‐dilation. Clinical outcomes were similar between patients who required post‐dilation compared to those who did not. In multivariable logistic regression analysis, only smaller valve cover index was found to be an independent predictor of 30‐day mild or greater aortic regurgitation (OR 0.007; 95% CI 0.0001–0.707; p = .035).

Conclusion

Acute elastic recoil of the SAPIEN‐3 valve was significantly less after post‐dilation as compared with after deployment. It was also greater when measured in the RAO view as compared with the LAO view. Furthermore, acute recoil was not homogenous across the height of the valve stent frame.
SBA‐15 Supported Chiral Phosphine‐Gold(I) Complex: Highly Efficient and Recyclable Catalyst for Asymmetric Cycloaddition Reactions
Authors: Yan Dong , Wang Nannan , Xue Teng , Wu Haihong , Zhang Junliang , Wu Peng
Published: May 2020

Ordered mesoporous SBA‐15 supported chiral phosphine gold (I) complexes were successfully developed. The gold(I) complexes were covalently immobilized on mercaptopropyl modified SiO2 surface through radical reaction. In this way, the chiral carbon and chiral sulfur of the homogenous catalyst were perfectly remained in situ. And thus, the prepared catalysts demonstrated highly effective asymmetric cycloaddition activity, which was likely because the chiral induction effect of the Au complex was hardly influenced by this immobilization method. Moreover, they could be easily recovered by simple filtration and directly used for the subsequent catalytic runs. The prepared catalyst was highly stable and efficient without obvious activity loss after eight cycles.
Flow Photochemistry as a Tool in Organic Synthesis
Authors: Rehm Thomas H.
Published: May 2020

Photochemical transformations of molecular building blocks have become an important and widely recognized research field in the past decade. Detailed and deep understanding of novel photochemical catalysts and reaction concepts with visible light as the energy source has enabled a broad application portfolio for synthetic organic chemistry. In parallel, continuous‐flow chemistry and microreaction technology have become the basis for thinking and doing chemistry in a novel fashion with clear focus on improved process control for higher conversion and selectivity. As can be seen by the large number of scientific publications on flow photochemistry in the recent past, both research topics have found each other as exceptionally well‐suited counterparts with high synergy by combining chemistry and technology. This review will give an overview on selected reaction classes, which represent important photochemical transformations in synthetic organic chemistry, and which benefit from mild and defined process conditions by the transfer from batch to continuous‐flow mode.
Molecular Engineering of Metal Alkoxides for Solution Phase Synthesis of High‐Tech Metal Oxide Nanomaterials
Authors: Mishra Shashank , Daniele Stéphane
Published: May 2020

The ‘bottom‐up’ synthesis of inorganic nanomaterials with precision at the atomic/molecular level offers many opportunities for the design and improvement of the nanomaterials for various applications. Molecular engineering during soft chemical processing for the synthesis of functional nanomaterials enables the desired chemical and physical properties of the precursors, such as solubility or volatility, clean decomposition, control of stoichiometry for multimetallic species to name a few, and leads to easy control of uniform particle size distribution, stoichiometry…. This Minireview illustrates some important aspects of the molecular engineering in light of some recent developments from the molecular synthesis of nanomaterials involving non‐silicon metal alkoxide systems for high‐tech applications.
Ferrimagnetic Ordering and Anomalous Stoichiometry Observed for the Cubic, Extended 3D Prussian Blue Analogues (NEt3Me)2MnII5(CN)12 and (NEt2Me2)2MnII5(CN)12: A Cation‐Adaptive Structure
Authors: Graham Adora G. , Lapidus Saul H. , Hawkins Casey G. , Stephens Peter W. , Miller Joel S.
Published: May 2020

The reactions of MnII(O2CCH3)2 with NEt3Me+CN− and NEt2Me2+CN− form (NEt3Me)2MnII5(CN)12 (1) and (NEt2Me2)2MnII5(CN)12 (2), respectively. Structure model‐building and Rietveld refinement of high‐resolution synchrotron powder diffraction data revealed a cubic [a=24.0093 Å (1), 23.8804 Å (2)] 3D extended structural motif with adjacent tetrahedral and octahedral MnII sites in a 3:2 ratio. Each tetrahedral MnII site is surrounded by four low‐spin octahedral MnII sites, and each octahedral MnII site is surrounded by six high‐spin tetrahedral MnII sites; adjacent sites are antiferromagnetically coupled in 3D. Compensation does not occur, and magnetic ordering as a ferrimagnet is observed at Tc=13 K for 2 based on the temperature at which remnant magnetization, Mr(T)→0. The hysteresis has an unusual constricted shape with inflection points around 50 and 1.2 kOe with a 5 K coercivity of 16 Oe and remnant magnetization, Mr, of 2050 emuOe mol−1. The unusual structure and stoichiometry are attributed to the very ionic nature of the high‐spin N‐bonded MnII ion, which enables the maximization of the attractive van der Waals interactions through minimization of void space via a reduced ∠ MnNC. This results in an additional example of the AxMnIIy(CN)x+2y (x=0, y=1; x=1, y=3; x=2, y=1; x=2, y=2; x=2, y=3; x=3, y=5; and x=4, y=1) family of compounds possessing an unprecedented stoichiometry and lattice motif that are cation adaptive structured materials.
An Intramolecular Hydrogen‐Shift in a Peroxy Radical at Cryogenic Temperatures: The Reaction of 2‐Hydroxyphenyl Radical with O2
Authors: Wagner J. Philipp
Published: May 2020

Peroxy radical hydrogen‐shifts are pivotal elementary reaction steps in the oxidation of small hydrocarbons in autoignition and the lower atmosphere. Although these reactions are typically associated with a substantial barrier, we demonstrate that the [1,5]H‐shift in the peroxy species derived from the 2‐hydroxyphenyl radical1is so facile that it even proceeds rapidly in an argon matrix at 35 K through a proton‐coupled electron transfer mechanism. Hydrogen‐bound complexes ofo‐benzoquinone are identified as the main reaction products by infrared spectroscopy although their formation through O−O bond scission is hampered by a barrier of 11.9 kcal mol−1at the ROCCSD(T)/cc‐pVTZ/UB3LYP/6–311G(d,p) level of theory.
Self‐Assembly Propensity Dictates Lifetimes in Transient Naphthalimide–Dipeptide Nanofibers
Authors: Kumar Mohit , Sementa Deborah , Narang Vishal , Riedo Elisa , Ulijn Rein V.
Published: May 2020

Transient self‐assembly of dipeptide nanofibers with lifetimes that are predictably variable through dipeptide sequence design are presented. This was achieved using 1,8‐naphthalimide (NI) amino acid methyl‐esters (Phe, Tyr, Leu) that are biocatalytically coupled to amino acid‐amides (Phe, Tyr, Leu, Val, Ala, Ser) to form self‐assembling NI‐dipeptides. However, competing hydrolysis of the dipeptides results in disassembly. It was demonstrated that the kinetic parameters like lifetimes of these nanofibers can be predictably regulated by the thermodynamic parameter, namely the self‐assembly propensity of the constituent dipeptide sequence. These lifetimes could vary from minutes, to hours, to permanent gels that do not degrade. Moreover, the in‐built NI fluorophore was utilized to image the transient nanostructures in solution with stimulated emission depletion (STED) based super‐resolution fluorescence microscopy.
Second Comes First: Switching Elementary Steps in Palladium‐Catalyzed Cross‐Coupling Reactions
Authors: Kolter Marlene , Koszinowski Konrad
Published: May 2020

The electron‐poor palladium(0) complex L3Pd (L=tris[3,5‐bis(trifluoromethyl)phenyl]phosphine) reacts with Grignard reagents RMgX and organolithium compounds RLi via transmetalation to furnish the anionic organopalladates [L2PdR]−, as shown by negative‐ion mode electrospray‐ionization mass spectrometry. These palladates undergo oxidative additions of organyl halides R′X (or related SN2‐type reactions) followed by further transmetalation. Gas‐phase fragmentation of the resulting heteroleptic palladate(II) complexes results in the reductive elimination of the cross‐coupling products RR′. This reaction sequence corresponds to a catalytic cycle, in which the order of the elementary steps of transmetalation and oxidative addition is switched relative to that of palladium‐catalyzed cross‐coupling reactions proceeding via neutral intermediates. An attractive feature of the palladate‐based catalytic system is its ability to mediate challenging alkyl–alkyl coupling reactions. However, the poor stability of the phosphine ligand L against decomposition reactions has so far prevented its successful use in practical applications.
Density Functional Theory Study of Pd Aggregation on a Pyridine‐Terminated Self‐Assembled Monolayer
Authors: Yao Zhen , Buck Manfred , Bühl Michael
Published: May 2020

By using density functional theory calculations, the initial steps towards Pd metal cluster formation on a pyridine‐terminated self‐assembled monolayer (SAM) consisting of 3‐(4‐(pyridine‐4‐yl)phenyl)propane‐1‐thiol on an Au(1 1 1) surface are investigated. Theoretical modelling allows the investigation of structural details of the SAM surface and the metal/SAM interface at the atomic level, which is essential for elucidating the nature of Pd–SAM and Pd–Pd interactions at the liquid/solid interface and gaining insight into the mechanism of metal nucleation in the initial stage of electrodeposition. The structural flexibility of SAM molecules was studied first and the most stable conformation was identified, planar molecules in a herringbone packing, as the model for Pd adsorption. Two binding sites are found for Pd atoms on the pyridine end group of the SAM. The strong interaction between Pd atoms and pyridines illustrates the importance of SAM functionalisation in the metal nucleation process. Consistent with an energetic driving force of approximately −0.3 eV per Pd atom towards Pd aggregation suggested by static calculations, a spontaneous Pd dimerisation is observed in ab initio molecular dynamic studies of the system. Nudged elastic band calculations suggest a potential route with a low energy barrier of 0.10 eV for the Pd atom diffusion and then dimerisation on top of the SAM layer.
Atomic‐Scale Dispersed Fe‐Based Catalysts Confined on Nitrogen‐Doped Graphene for Li‐S Batteries: Polysulfides with Enhanced Conversion Efficiency
Authors: Cao Guiqiang , Wang Zhikang , Bi Da , Zheng Jing , Lai Qingxue , Liang Yanyu
Published: May 2020

Lithium‐sulfur batteries have been considered as potential electrochemical energy‐storage devices owing to their satisfactory theoretical energy density. Nonetheless, the inferior conversion efficiency of polysulfides in essence leads to fast capacity decay during the discharge/charge cycle. In this work, it is successfully demonstrated that the conversion efficiency of lithium polysulfides is remarkably enhanced by employing a well‐distributed atomic‐scale Fe‐based catalyst immobilized on nitrogen‐doped graphene (Fe@NG) as a coating of separator in lithium‐sulfur batteries. The quantitative electrocatalytic efficiency of the conversion of lithium polysulfides is determined through cyclic voltammetry. It is also proven that the Fe‐NX configuration with highly catalytic activity is quite beneficial for the conversion of lithium polysulfides. In addition, the adsorption and permeation experiments distinctly indicate that the strong anchoring effect, originated from the charge redistribution of N doping into the graphene matrix, inhibits the movement of lithium polysulfides. Thanks to these advantages, if the as‐prepared Fe@NG catalyst is combined with polypropylene and applied as a separator (Fe@NG/PP) in Li‐S batteries, a high initial capacity (1616 mA h g−1 at 0.1 C), excellent capacity retention (93 % at 0.2 C, 70 % at 2 C), and superb rate performance (820 mA h g−1 at 2 C) are achieved.