bluuebunny/crossref_metadata_2025 huggingface dataset:
B‐Cu‐Zn Gas Diffusion Electrodes for CO2 Electroreduction to C2+ Products at High Current Densities
Authors: Song Yanfang , Junqueira João R. C. , Sikdar Nivedita , Öhl Denis , Dieckhöfer Stefan , Quast Thomas , Seisel Sabine , Masa Justus , Andronescu Corina , Schuhmann Wolfgang
Published: February 2021

Electroreduction of CO2 to multi‐carbon products has attracted considerable attention as it provides an avenue to high‐density renewable energy storage. However, the selectivity and stability under high current densities are rarely reported. Herein, B‐doped Cu (B‐Cu) and B‐Cu‐Zn gas diffusion electrodes (GDE) were developed for highly selective and stable CO2 conversion to C2+ products at industrially relevant current densities. The B‐Cu GDE exhibited a high Faradaic efficiency of 79 % for C2+ products formation at a current density of −200 mA cm−2 and a potential of −0.45 V vs. RHE. The long‐term stability for C2+ formation was substantially improved by incorporating an optimal amount of Zn. Operando Raman spectra confirm the retained Cu+ species under CO2 reduction conditions and the lower overpotential for *OCO formation upon incorporation of Zn, which lead to the excellent conversion of CO2 to C2+ products on B‐Cu‐Zn GDEs.
Photo‐Mediated Intermolecular Coupling of Alkenes with Ketones via Acyloxy Nitroso Compounds
Authors: Zheng Danqing , Plöger Stefanie , Daniliuc Constantin G. , Studer Armido
Published: February 2021

An atom‐economic intermolecular radical addition reaction of acyloxy nitroso compounds to electron‐deficient alkenes mediated by visible light is reported. The starting nitroso derivatives are readily prepared by oxidation of the corresponding oximes prepared from ketones and the overall transformation represents an oxidative coupling of a ketone with a Michael acceptor. The cascade proceeds smoothly under mild conditions, providing a series of valuable functionalized oximes in moderate to good yields. Mechanistic studies suggest that these cascades proceed via addition/coupling processes that are controlled by the persistent radical effect (PRE) with NO acting as the persistent species.
Temperature memory effect from below glass transition to up to melting range in an ethylene‐vinyl acetate copolymer
Authors: Wang Tao Xi , Song Lei Peng , Geng Yun Hui , Shen Xing
Published: February 2021

In this paper, the temperature memory effect (TME) in a commercial ethylene‐vinyl acetate copolymer (EVA) is characterized via differential scanning calorimetry (DSC) tests. Three temperatures, which are 35, 60, and 85°C representing temperatures below glass transition (Tg), within Tg and within melting (Tm), respectively, are included for the investigation. It is found that TME in polymers is not as reported to be limited at around either Tg or Tm only, the effective temperature range for TME could be actually much wider that covers from below Tg to up to Tm. In addition, it is concluded that higher heating stop temperature (Ts) erases the memory of previous lower ones in this EVA. Hysteresis (described by ΔT) between the temperature of turning points (Tts) and their corresponding Tss is always observable. However, the ΔT decreases at higher Ts.
N‐dodecylated chitosan/graphene oxide composite cryogel for hemostasis and antibacterial treatment
Authors: Qiu Yixuan , Dong Yanliang , Zhao Shuyue , Zhang Jianhua , Huang Pingsheng , Wang Weiwei , Dong Anjie , Deng Liandong
Published: February 2021

Uncontrolled massive bleeding remains a global issue, which requires an exigent response for safe and efficient hemostat. However, most of hemostats without antimicrobial property could trigger serious bacterial infection problem. Herein, a composite cryogel was synthesized by double bond N‐dodecylated chitosan (DCSG) and graphene oxide (GO). The cryogel (DCSG/GO) with macroporous structure exhibited high‐fluid adsorption ability, excellent mechanical property, and fluid‐triggered shape recovery performance. Moreover, the in vitro blood coagulation experiments proved that DCSG/GO5% possessed better coagulation efficiency than medical gelatin sponge. And the DCSG/GO5% cryogel exhibited more erythrocyte and platelets activation. Besides, the cryogel had excellent near‐infrared (NIR)‐assisted photothermal antibacterial activity against both Escherichia coli and Staphylococcus aureus and killed 99% of them after 20 min NIR irradiation. In addition, the vitro hemolysis and cytotoxicity results proved the well biocompatibility of cryogel. Therefore, the biocompatible DCSG/GO cryogel has great potential application prospect in clinical hemorrhage control and anti‐infection treatment.
Assessing the role of the aquatic Natura 2000 network to protect both freshwater European species of community interest and threatened species in a Mediterranean region
Authors: Sánchez‐Fernández David , Baquero Rocío A. , Velasco Luis , Aranda Antonio , Nicola Graciela G.
Published: February 2021

The European Natura 2000 (N2K) network of protected areas stands out as the main conservation strategy in the European Union to preserve biodiversity under the auspices of the Convention on Biological Diversity.

The management of N2K sites is mainly focused on protecting the biological elements as Special Areas of Conservation for habitats or species listed in the European Habitats Directive, or as Special Protection Areas for birds listed in the European Birds Directive for which the site was designated. It seems urgent, therefore, to discriminate which N2K sites are really providing effective protection for aquatic biodiversity.

Although the main objective of N2K is to protect species listed in the Birds and Habitats Directives, the conservation status of threatened species included in the European Red List of the IUCN must also be a concern for the European Union.

Focusing on Central Spain as a case study, the aim of this work was to evaluate how far aquatic N2K (i.e. N2K sites designated for the occurrence of freshwater elements) is effective in protecting both those aquatic species in the Directives [referred to here as Species of Community Importance (SCI) and threatened species (TS)].

Most of the N2K sites in the study area have been designated using aquatic elements, which means that N2K could theoretically provide appropriate mechanisms to preserve aquatic biodiversity. However, N2K provides a low percentage of overlap with some of the hotspots identified for both TS and SCI. Surprisingly, TS are in general similarly or even better represented than SCI by N2K.

N2K may provide good coverage for aquatic biodiversity, mainly by acting as an umbrella for other species, but it could be improved by addressing some spatial gaps, thereby making it more relevant to current challenges such as climate change and other human impacts.
Retinoic Acid Receptor–Related Orphan Nuclear Receptor γt Licenses the Differentiation and Function of a Unique Subset of Follicular Helper T Cells in Response to Immunogenic Self‐DNA in Systemic Lupus Erythematosus
Authors: Wen Zhenke , Xu Lin , Xu Wei , Xiong Sidong
Published: February 2021

Objective

Accumulating studies have identified self‐DNA as driving IgG anti–double‐stranded DNA (anti‐dsDNA) in lupus, though the underpinning mechanisms of this process remain largely undefined. Here, we explored the activity of transcription factor retinoic acid receptor–related orphan nuclear receptor γt (RORγt) in the differentiation and function of self‐DNA–specific follicular helper T (Tfh) cells in lupus.

Methods

B6, TCRα–/–, CD4–/–, RORγtfl/flCD4Cre, RORγt+/+CD4Cre, Bcl‐6fl/flCD4Cre, Bcl‐6+/+CD4Cre, IL‐17–/–, and ICOS–/– mice were immunized with normal self‐DNA, immunogenic self‐DNA, and pathogen DNA to induce the production of Tfh cells and IgG anti‐dsDNA. Tfh cells with or without interleukin‐17 (IL‐17) were evaluated for their role in supporting the generation of IgG. NSG mice were reconstituted with immune cells and circulating DNA from human subjects for translational studies. IL‐17–positive Tfh cells were analyzed for their correlation with IgG anti‐dsDNA levels as well as their response to circulating self‐DNA in lupus patients.

Results

Unlike normal self‐DNA, immunogenic self‐DNA and pathogen DNA efficiently induced IgG responses. Immunogenic self‐DNA induced IgG in a CD4+ T cell–dependent manner, which was abrogated by RORγt deficiency. In contrast, RORγt was not required for the generation of pathogen DNA–induced IgG. Further analyses identified RORγt as essential for the differentiation and function of Tfh cells in response to immunogenic self‐DNA, assigning IL‐17 as a feature cytokine. These IL‐17–positive Tfh cells functioned independent of inducible costimulator (ICOS), critically supporting IgG generation. Targeting immunogenic self‐DNA–specific Tfh cells by RORγ knockdown and IL‐17 blockade ameliorated IgG response and lupus nephritis in a humanized mouse model. The presence of IL‐17–positive Tfh cells was associated with IgG anti‐dsDNA levels and were expanded by circulating immunogenic self‐DNA in lupus patients.

Conclusion

Immunogenic self‐DNA instructs ICOS‐dispensable IL‐17–positive Tfh cells via RORγt to produce an IgG anti‐dsDNA response. As such, IL‐17–positive Tfh cells are a promising therapeutic target for lupus patients.
Carbon Dot−NaCl Crystals for White‐Light Generation and Fabry‐Perot Lasing
Authors: Prakash Swayam , Sahu Saugata , Bhattacharya Shubhayan , Bisht Prem B. , Mishra Ashok Kumar
Published: February 2021

Phosphor materials with broad spectral range and an average emission lifetime (20 μs) have been achieved from carbon dots (CDs)−NaCl crystals. A one‐pot synthesis pathway has been developed for CDs−NaCl crystals formation at room temperature. Precursor for CDs materials was screened at room temperature by oxidation methodology from different simple sugar molecules. CDs (size less than 10 nm) prepared from the fructose sugar exhibit most intense emission. Utilizing ripe banana peel (contains ∼27% of fructose) as a precursor for the carbon dot formation, white‐light emission with a CIE index of (0.29, 0.34) has been achieved from the single source with CDs−NaCl crystals upon excitation at 430 nm. The crystals also function as Fabry‐Perot (F−P) mode resonator for lasing, with a laser threshold value of 0.9 mW and a resonating Q‐factor of 207. These results outline a new approach for realizing F−P lasing and white light emission from a non‐toxic green source with a quick, facile and low‐cost synthesis procedure.
Penicillium fellutanum lipase as a green and ecofriendly biocatalyst for depolymerization of poly (ɛ‐caprolactone): Biochemical, kinetic, and thermodynamic investigations
Authors: Amin Misbah , Bhatti Haq Nawaz , Nawaz Sadia , Bilal Muhammad
Published: February 2021

Microbial lipases hold a prominent position in biocatalysis by their capability to mediate reactions in aqueous and nonaqueous media. Herein, a lipase from Penicillium fellutanum was biochemically characterized and investigated its potential to degrade poly (ɛ‐caprolactone) (PCL). The lipase exhibited stability over a broad pH spectrum and performed best at pH 8.5 and 45 °C. The activation energy was determined to be 66.37 kJ/mol by Arrhenius plot, whereas Km and Vmax for pNPP hydrolysis were 0.75 mM and 83.33 μmol/mL/Min, respectively. A rise in temperature reduced the Gibbs free energy, whereas the enthalpy of thermal unfolding (∆H*) remains the same up to 54 °C following a modest decline at 61 °C. The entropy (∆S*) of the enzyme demonstrated an increasing trend up to 54 °C and dropped at 61 °C. Lipase retained stability by incubation with various industrially relevant organic solvents (benzene, hexanol, ether, and acetone). However, exposure to urea and guanidine hydrochloride influenced its catalytic activity to different extents. Under optimal operating conditions, lipase catalyzed the excellent degradation of PCL film degradation leading to 66% weight loss, increased surface erosion, and crystallinity. Fourier‐transform infrared spectrometry, differential scanning calorimetry, and scanning electron microscopy studies monitored the weight loss after enzymatic hydrolysis. The findings indicate that P. fellutanum lipase would be a prospective biocatalytic system for polyesters depolymerization and environmental remediation.
Positionspapier „Beton ohne Steinkohlenflugasche“
Authors: Voland Katja , Westendarp Andreas
Published: February 2021

Aufgrund des schrittweisen Ausstiegs aus der Kohleverstromung stehen bereits heute deutlich geringere Mengen an in Deutschland produzierten Steinkohlenflugaschen zur Verfügung. Spätestens im Jahr 2038 wird ihr Anteil auf null fallen. Der Deutsche Beton‐ und Bautechnik‐Verein E.V. (DBV) sowie die Bundesanstalt für Wasserbau (BAW) verfolgen mit diesem Positionspapier das Ziel, alle am Bau Beteiligten über die daraus resultierenden Lieferengpässe von Steinkohlenflugasche zu informieren und Verständnis dafür zu schaffen. Zudem zeigen sie in diesem Papier erste Lösungsansätze auf, um die negativen Auswirkungen auf die Betonbauweise weitestgehend zu minimieren.
Development of cell‐based high throughput luminescence assay for drug discovery in inhibiting OCT4/DNA‐PKcs and OCT4–MK2 interactions
Authors: Mohiuddin Ismail S. , Wei Sung‐Jen , Yang In‐Hyoung , Martinez Gloria M. , Yang Shengping , Cho Eun J. , Dalby Kevin N. , Kang Min H.
Published: February 2021

Amplification‐independent c‐MYC overexpression is suggested in multiple cancers. Targeting c‐MYC activity has therapeutic potential, but efforts thus far have been mostly unsuccessful. To find a druggable target to modulate c‐MYC activity in cancer, we identified two kinases, MAPKAPK2 (MK2) and the DNA‐dependent protein kinase catalytic subunit (DNA‐PKcs), which phosphorylate the Ser111 and the Ser93 residues of OCT4, respectively, to transcriptionally activate c‐MYC. Using these observations, we present here a novel cell‐based luminescence assay to identify compounds that inhibit the interaction between these kinases and OCT4. After screening approximately 80,000 compounds, we identified 56 compounds (“hits”) that inhibited the luminescence reaction between DNA‐PKcs and OCT4, and 65 hits inhibiting the MK2–OCT4 interaction. Using custom antibodies specific for pOCT4S93 and pOCT4S111, the “hits” were validated for their effect on OCT4 phosphorylation and activation. Using a two‐step method for validation, we identified two candidate compounds from the DNA‐PKcs assay and three from the MK2 assay. All five compounds demonstrate a significant ability to kill cancer cells in the nanomolar range. In conclusion, we developed a cell‐based luminescence assay to identify novel inhibitors targeting c‐MYC transcriptional activation, and have found five compounds that may function as lead compounds for further development.
The role of interindividual licking received and dopamine genotype on later‐life licking provisioning in female rat offspring
Authors: Lauby Samantha C. , Ashbrook David G. , Malik Hannan R. , Chatterjee Diptendu , Pan Pauline , Fleming Alison S. , McGowan Patrick O.
Published: February 2021

Introduction

Rat mothers exhibit natural variations in care that propagate between generations of female offspring. However, there is limited information on genetic variation that could influence this propagation.

Methods

We assessed early‐life maternal care received by individual female rat offspring, later‐life maternal care provisioning, and dopaminergic activity in the maternal brain in relation to naturally occurring genetic polymorphisms linked to the dopaminergic system. We also conducted a systematic analysis of other genetic variants potentially related to maternal behavior in our Long‐Evans rat population.

Results

While we did not find a direct relationship between early‐life licking received and later‐life licking provisioning, this relationship was indirectly affected by dopamine levels in the nucleus accumbens and dependent on variation in the dopamine receptor 2 gene (rs107017253). More specifically, female rat offspring with the A/G genotype showed a positive relationship between average licking received and dopamine levels in the nucleus accumbens of the maternal brain; there was no relationship with female rat offspring with the A/A genotype. The higher dopamine levels in the nucleus accumbens corresponded with higher maternal licking provisioning from postnatal days 2–9. We also discovered and validated several new variants that were predicted by our systematic analysis.

Conclusion

Our findings suggest that genetic variation influences the relationship between early‐life maternal care received and the dopaminergic system of the maternal brain, which can indirectly influence later‐life maternal care provisioning.
WTAP facilitates progression of endometrial cancer via CAV‐1/NF‐κB axis
Authors: Li Qin , Wang Chenyu , Dong Wei , Su Yi , Ma Zhao
Published: February 2021

The N6‐methyladenosine (m6A) modification is one of the most prevalent methylations in eukaryotic messenger RNA (mRNA), and it is essential for the development of many important biological processes such as multiple types of tumors. One of the most important enzymes catalyzing generation of m6A on mRNA is Wilms' tumor 1‐associating protein (WTAP); however, the potential role of WTAP in endometrial cancer (EC) still remains unknown. Here, we investigated WTAP expression level in cancer tissue and paracancerous tissue from an EC patient. Subsequently, WTAP was knocked down by small interfering RNA in EC cell line of Ishikawa and HEC‐1A, respectively. Cell proliferation, migration, and invasion were studied. The expression of caveolin‐1 (CAV‐1) was detected by quantitative polymerase chain reaction (qPCR). The enrichments of m6A and METTL3 on CAV‐1 were detected using RNA immunoprecipitation‐qPCR. The activity of nuclear factor‐κB (NF‐κB) was studied using Western blot. We observed that WTAP was dramatically upregulated in the cancer tissue, and there was an enhancement in cell proliferation, migration, and invasion and a decrease in EC apoptosis in vivo and in vitro, which indicated higher tumor malignancy and worse survival outcome. After WTAP was knocked down in EC cells, CAV‐1 was significantly upregulated and the enrichments of m6A and METTL3 at 3′‐untranslated region (UTR) region of CAV‐1 were decreased. Moreover, the activity of NF‐κB signaling pathway was inhibited by its regulator CAV‐1. Taken together, we concluded that WTAP could methylate 3′‐UTR of CAV‐1 and downregulate CAV‐1 expression to activate NF‐κB signaling pathway in EC, which promoted EC progression.
Pericardial release for early LVAD malalignment a less invasive approach
Authors: Jeng Eric I. , Ghannam Alexander D. , Ahmed Mustafa M.
Published: February 2021

In a previously well‐functioning LVAD, pericardial release via thoracotomy may improve inflow angle and correct malpositioning to ultimately restore LVAD function and patient hemodynamics. To prevent this, we recommend that implantations include a longitudinal pericardiotomy and anchoring sutures.
Gastric pull‐up with laryngeal preservation of the primary synovial sarcoma of the esophagus: A case report
Authors: Ahmadi Aslan , Firouzabadi Mohammad Dehghani , Sanaei Ayda , Ghanbari Hadi , Roomiani Maryam
Published: February 2021

In patients who require a gastric pull‐up, despite bilateral injury to the vocal cords and regurgitation, preservation of the larynx can improve their quality of life.
Carbon Cloth Supported Nitrogen Doped Porous Carbon Wrapped Co Nanoparticles for Effective Overall Water Splitting
Authors: Zhu Jun , Shen Xiaoping , Yue Xiaoyang , Fan Chen , Kong Lirong , Ji Zhenyuan , Zhu Guoxing , Xu Keqiang , Zhou Hu
Published: February 2021

The key to the practical application of overall water splitting is to develop high‐efficient non‐noble metal electrocatalysts. Herein, carbon cloth supported N‐doped porous carbon wrapped Co nanoparticles (CC@Co‐NPC) are constructed with high bifunctional catalytic activity toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline medium. Benefiting from the exposure of abundant Co active sites, and the synergistic effect between Co particles and N‐doped carbon species, the CC@Co‐NPC delivers small overpotentials of 286 and 340 mV at 100 mA cm−2 with Tafel values of 59 and 97 mV dec−1 towards OER and HER, respectively. Remarkably, when coupled as CC@Co‐NPC||CC@Co‐NPC cell, only a small voltage of 1.49 V is required to achieve 10 mA cm−2, making CC@Co‐NPC a potential bifunctional catalyst for overall water splitting.
Insights into the Voltammetry of Cavity Microelectrodes Filled with Metal Powders: The Value of Square Wave Voltammetry
Authors: Torralba Encarnación , Laborda Eduardo , Molina Angela , Cachet‐Vivier Christine , Bastide Stéphane
Published: February 2021

Cavity microelectrodes (CMEs) offer a valuable platform to evaluate the electrocatalytic performance of micro‐ and nanoparticulate materials. The technical factors and physicochemical processes affecting the electrochemical response at CMEs are to be recognized; specifically, the accessibility of redox species to the electrocatalyst surface. With this aim, the voltammetric response of CMEs is investigated through a joint experimental and theoretical approach including a comparative study of cyclic and square wave voltammetry (SWV). Experiments reveal a capacitive distortion of the response that increases with the powder surface area, but with a faradaic response analogous to that of recessed or inlaid microdisks, that is, with electrochemical reactions occurring essentially on the first layer of the powder load. We show that SWV is well suited to discriminate faradaic processes at CMEs and we present accurate mathematical expressions to describe it. These results provide guidelines for the design and analysis of CME voltammetric measurements.
Multifunctional roles of carbon‐based hosts for Li‐metal anodes: A review
Authors: Yan Xiaolin , Lin Liang , Chen Qiulin , Xie Qingshui , Qu Baihua , Wang Laisen , Peng Dong‐Liang
Published: February 2021

With its high theoretical capacity, lithium (Li) metal is recognized as the most potential anode for realizing a high‐performance energy storage system. A series of questions (severe safety hazard, low Coulombic efficiency, short lifetime, etc.) induced by uncontrollable dendrites growth, unstable solid electrolyte interface layer, and large volume change, make practical application of Li‐metal anodes still a threshold. Due to their highly appealing properties, carbon‐based materials as hosts to composite with Li metal have been passionately investigated for improving the performance of Li‐metal batteries. This review displays an overview of the critical role of carbon‐based hosts for improving the comprehensive performance of Li‐metal anodes. Based on correlated mainstream models, the main failure mechanism of Li‐metal anodes is introduced. The advantages and strategies of carbon‐based hosts to address the corresponding challenges are generalized. The unique function, existing limitation, and recent research progress of key carbon‐based host materials for Li‐metal anodes are reviewed. Finally, a conclusion and an outlook for future research of carbon‐based hosts are presented. This review is dedicated to summarizing the advances of carbon‐based materials hosts in recent years and providing a reference for the further development of carbon‐based hosts for advanced Li‐metal anodes.
Directed Assembly of Multi‐Walled Nanotubes and Nanoribbons of Amino Acid Amphiphiles Using a Layer‐by‐Layer Approach
Authors: Siegl Kathrin , Kolik‐Shmuel Luba , Zhang Mingming , Prévost Sylvain , Vishnia Kalanit , Mor Amram , Appavou Marie‐Sousai , Jafta Charl J. , Danino Dganit , Gradzielski Michael
Published: February 2021

Monodisperse unilamellar nanotubes (NTs) and nanoribbons (NRs) were transformed to multilamellar NRs and NTs in a well‐defined fashion. This was done by using a step‐wise approach in which self‐assembled cationic amino acid amphiphile (AAA) formed the initial NTs or NRs, and added polyanion produced an intermediate coating. Successive addition of cationic AAA formed a covering AAA layer, and by repeating this layer‐by‐layer (LBL) procedure, multi‐walled nanotubes (mwNTs) and nanoribbons were formed. This process was structurally investigated by combining small‐angle neutron scattering (SANS) and cryogenic‐transmission electron microscopy (cryo‐TEM), confirming the multilamellar structure and the precise layer spacing. In this way the controlled formation of multi‐walled suprastructures was demonstrated in a simple and reproducible fashion, which allowed to control the charge on the surface of these 1D aggregates. This pathway to 1D colloidal materials is interesting for applications in life science and creating well‐defined building blocks in nanotechnology.
Sulfur Tetrahydride and Allied Superhydride Clusters: When Resonance Takes Precedence
Authors: Weinhold Frank
Published: February 2021

Sulfur offers a variety of bonding surprises compared to the parent oxygen atom of the chalcogen family. In the present work, we employ standard quantum chemistry methods to characterize formation of previously unrecognized sulfur tetrahydride (C4v‐symmetric SH4) from hydrogen sulfide (H2S) and molecular hydrogen (H2) on the ground state potential energy surface. The unusual intramolecular interactions of SH4 defy Lewis‐like bonding conceptions, exhibiting the dominance of resonance‐type donor‐acceptor delocalizations well beyond those of SF4 (C2v sawhorse geometry) and other known tetrahalides. The distressed character of SH4 bonding also leads to exotic intermolecular structural motifs in clusters of pure (SH4)n and mixed (SH4⋅⋅⋅H2S)n composition. We evaluate structural, spectroscopic, and electronic properties for various 2D/3D coordination patterns and discuss how (SH4⋅⋅⋅H2S)n‐type building blocks may relate to recent experimental studies of superconductivity in high‐pressure materials of “SH3” stoichiometry.
Conformational Dependence of Triplet Energies in Rotationally Hindered N‐ and S‐Heterocyclic Dimers: New Design and Measurement Rules for High Triplet Energy OLED Host Materials
Authors: Wright Iain A. , Danos Andrew , Montanaro Stephanie , Batsanov Andrei S. , Monkman Andrew P. , Bryce Martin R.
Published: February 2021

A series of four heterocyclic dimers has been synthesized, with twisted geometries imposed across the central linking bond by ortho‐alkoxy chains. These include two isomeric bicarbazoles, a bis(dibenzothiophene‐S,S‐dioxide) and a bis(thioxanthene‐S,S‐dioxide). Spectroscopic and electrochemical methods, supported by density functional theory, have given detailed insights into how para‐ vs. meta‐ vs. broken conjugation, and electron‐rich vs. electron‐poor heterocycles impact the HOMO–LUMO gap and singlet and triplet energies. Crucially for applications as OLED hosts, the triplet energy (ET) of these molecules was found to vary significantly between dilute polymer films and neat films, related to conformational demands of the molecules in the solid state. One of the bicarbazole species shows a variation in ET of 0.24 eV in the different media—sufficiently large to “make‐or‐break” an OLED device—with similar discrepancies found between neat films and frozen solution measurements of other previously reported OLED hosts. From consolidated optical and optoelectronic investigations of different host/dopant combinations, we identify that only the lower ET values measured in neat films give a reliable indicator of host/guest compatibility. This work also provides new molecular design rules for obtaining very high ET materials and controlling their HOMO and LUMO energies.
A Guide to Directing Group Removal: 8‐Aminoquinoline
Authors: Fitzgerald Liam S. , O'Duill Miriam L.
Published: February 2021

The use of directing groups allows high levels of selectivity to be achieved in transition metal‐catalyzed transformations. Efficient removal of these auxiliaries after successful functionalization, however, can be very challenging. This review provides a critical overview of strategies used for removal of Daugulis’ 8‐aminoquinoline (2005–2020), one of the most widely used N,N‐bidentate directing groups. The limitations of these strategies are discussed and alternative approaches are suggested for challenging substrates. Our aim is to provide a comprehensive end‐users’ guide for chemists in academia and industry who want to harness the synthetic power of directing groups—and be able to remove them from their final products.
Catechol‐Coordinated Framework Film‐based Micro‐Supercapacitors with AC Line Filtering Performance
Authors: Yu Tianliang , Wang Youfu , Jiang Kaiyue , Zhai Guangqun , Ke Changchun , Zhang Jichao , Li Jiantong , Tranca Diana , Kymakis Emmanuel , Zhuang Xiaodong
Published: February 2021

Coordination polymer frameworks (CPFs) have broad applications due to their excellent features, including stable structure, intrinsic porosity, and others. However, preparation of thin‐film CPFs for energy storage and conversion remains a challenge because of poor compatibility between conductive substrates and CPFs and crucial conditions for thin‐film preparation. In this work, a CPF film was prepared by the coordination of the anisotropic four‐armed ligand and CuII at the liquid–liquid interface. Such film‐based micro‐supercapacitors (MSCs) are fabricated through high‐energy scribing and electrolytes soaking. As‐fabricated MSCs displayed high volumetric specific capacitance of 121.45 F cm−3. Besides, the volumetric energy density of MSCs reached 52.6 mWh cm−3, which exceeds the electrochemical performance of most reported CPF‐based MSCs. Especially, the device exhibited alternating current (AC) line filtering performance (−84.2° at 120 Hz) and a short resistance capacitance (RC) constant of 0.08 ms. This work not only provides a new CPF for MSCs with AC line filtering performance but also paves the way for thin‐film CPFs preparation with versatile applications.
Fluorogenic Squaraine Dendrimers for Background‐Free Imaging of Integrin Receptors in Cancer Cells
Authors: Ashokkumar Pichandi , Collot Mayeul , Klymchenko Andrey S.
Published: February 2021

To overcome the limited brightness of existing fluorogenic molecular probes for biomolecular targets, we introduce a concept of fluorogenic dendrimer probe, which undergoes polarity‐dependent switching due to intramolecular aggregation‐caused quenching of its fluorophores. Based on a rational design of dendrimers with four and eight squaraine dyes, we found that octamer bearing dyes through a sufficiently long PEG(8) linker displays >400‐fold fluorescence enhancement from water to non‐polar dioxane. High extinction coefficient (≈2,300,000 m−1 cm−1) resulted from eight squaraine dyes and quantum yield (≈25 %) make this octamer the brightest environment‐sensitive fluorogenic molecule reported to date. Its conjugate with cyclic RGD used at low concentration (3 nm) enables integrin‐specific fluorescence imaging of cancer cells with high signal‐to‐background ratio. The developed dendrimer probe is a “golden middle” between molecular probes and nanoparticles, combining small size, turn‐on response and high brightness, important for bioimaging.
A Luminescent Two‐Coordinate AuIBimetallic Complex with a Tandem‐Carbene Structure: A Molecular Design for the Enhancement of TADF Radiative Decay Rate
Authors: Li Tian‐yi , Shlian Daniel G. , Djurovich Peter I. , Thompson Mark E.
Published: February 2021

A luminescent bimetallic AuIcomplex comprised ofN‐heterocyclic carbene (NHC) and carbazole (Cz) ligands, that is, (NHC’)Au(NHC)AuCz has been synthesized and studied. Both carbene ligands in the bimetallic complex act as electron acceptors in tandem to increase the energy separation between the ground and excited state, which is higher than those found in either monometallic analogue, (NHC)AuCz and (NHC’)AuCz. A coplanar geometry designed into the tandem complex ensures sufficient electronic coupling between the π‐orbitals of the ligands to impart a strong oscillator strength to the singlet intra‐ligand charge‐transfer (1ICT) transition. Theoretical modelling indicates that the emissive ICT excited state involves both NHC ligands. The tandem complex gives blue luminescence (λmax=480 nm) with a high photoluminescent quantum yield (ΦPL=0.80) with a short decay lifetime (τ=0.52 μs). Temperature‐dependent photophysical studies indicate that emission is via thermally assisted delayed fluorescence (TADF) and give a small singlet‐triplet energy difference (ΔEST=50 meV, 400 cm−1) consistent with the short TADF lifetime.
A predictive model using left atrial function and B‐type natriuretic peptide level in predicting the recurrence of early persistent atrial fibrillation after radiofrequency ablation
Authors: Yang Zhenni , Xu Min , Zhang Chuxu , Liu Huannian , Shao Xiaoliang , Wang Yuetao , Yang Ling , Yang Junhua
Published: February 2021

Aim

A predictive model using left atrial function indexes obtained by real‐time three‐dimensional echocardiography (RT‐3DE) and the blood B‐type natriuretic peptide (BNP) level was constructed, and its value in predicting recurrence in patients with early persistent atrial fibrillation (AF) after radiofrequency ablation was explored.

Methods

A total of 228 patients with early persistent AF who were scheduled to receive the first circular pulmonary vein ablation (CPVA) were enrolled. Clinical data of patients were collected: (1) The blood BNP level was measured before radiofrequency ablation; (2) RT‐3DE was used to obtain the left atrial (LA) time‐volume curve; (3) The clinical characteristics, BNP level and LA function parameters were compared, and logistic regression was used to construct a prediction model with combined parameters; (4) The receiver operating characteristic (ROC) curve was used to examine the diagnostic efficacy of the model.

Results

(1) 215 patients with early persistent AF completed CPVA and the follow‐up. After 3–6 months of follow‐up, the patients were divided into sinus rhythm group (160 cases) and recurrence group (55 cases); (2) The recurrence group showed higher minimum LA volume index, diastolic ejection index, and preoperative BNP (all p ≤ .001), while the sinus rhythm group exhibited higher expansion index (PI) and left atrial appendage peak emptying velocity (p ≤ .001); (3) In univariate analysis, BNP level had the best diagnostic performance in predicting the recurrence of AF(AUC = 0.703). We constructed a model based on LA function and BNP level to predict the recurrence of persistent AF after CPVA. This combined model was better than BNP alone in predicting the recurrence of persistent AF after CPVA (AUC: 0.814 vs. 0.703, z = 2.224, p = .026).

Conclusion

The combined model of LA function and blood BNP level has good predictive value for the recurrence of early persistent AF after CPVA.
Visual color research of packaging design using sensory factors
Authors: Kuo Lungwen , Chang Tsuiyueh , Lai Chih‐Chun
Published: February 2021

Package designs stimulate consumers visually and give rise to a sense of aesthetism, thus improving product visibility. In this study, emotions related to color combinations in packaging were addressed, cake packaging designs were tested, and affective design elements regarding styles and colors along with the diverse emotions that resulted were assessed and researched. Four experiments were conducted: Experiment 1 was on the affective characteristics related to types of colored boxes in packaging design; the best type of colored box for cakes was tested. In experiment 2, adjectives for emotions were compiled to identify adjectives for emotional responses to package designs. Experiment 3 was used to examine the fitness of single‐color boxes in packaging design; the colors of single‐color boxes were examined. In experiment 4, the focus was the fitness of dual‐color boxes in packaging design; an experiment on the best color combination was conducted with dual‐color boxes, and the results were then collected and analyzed to determine the fittest color combination for cake packaging design. According to the research findings, in the experiment on colored box types used in packaging design, the design with a five‐sided trapezoidal design was the most popular, followed by the colored box type with a rectangular handle in the middle; the selection of and experimentation on the adjectives for emotions revealed that Exquisite‐Rough was the fittest for the experiment, followed by Lively‐Dull; the fittest single‐color box was orange (Pantone715 C,L69.6,A37.0,B65.8), followed by gray (Pantone Gray Cool Gray 1C,L86.4,A0.1,B1.1); the fittest dual‐color box was in orange and orange red (Pantone Orange 021C, C,L60.0,A65.2,B71.4), followed by orange and black (Pantone Black C,L17.3,A0.8,B3.1). The experiment in this study focused on the color packaging of boxes for cakes; its results provide theoretical and practical references, for future research and orientation, regarding colors and types of colored boxes used for various products.
Kinetically Stable Nonequilibrium Gold‐Cobalt Alloy Nanoparticles with Magnetic and Plasmonic Properties Obtained by Laser Ablation in Liquid
Authors: Guadagnini Andrea , Agnoli Stefano , Badocco Denis , Pastore Paolo , Pilot Roberto , Ravelle‐Chapuis Régis , van Raap Marcela B. Fernández , Amendola Vincenzo
Published: February 2021

Nonequilibrium nanoalloys are metastable solids obtained at the nanoscale under nonequilibrium conditions that allow the study of kinetically frozen atoms and the discovery of new physical and chemical properties. However, the stabilization of metastable phases in the nanometric size regime is challenging and the synthetic route should be easy and sustainable, for the nonequilibrium nanoalloys to be practically available. Here we report on the one‐step laser ablation synthesis in solution (LASiS) of nonequilibrium Au−Co alloy nanoparticles (NPs) and their characterization on ensembles and at the single nanoparticle level. The NPs are obtained as a polycrystalline solid solution stable in air and water, although surface cobalt atoms undergo oxidation to Co(II). Since gold is a renowned plasmonic material and metallic cobalt is ferromagnetic at room temperature, these properties are both found in the NPs. Besides, surface conjugation with thiolated molecules is possible and it was exploited to obtain colloidally stable solutions in water. Taking advantage of these features, an array of magnetic‐plasmonic dots was obtained and used for surface‐enhanced Raman scattering experiments. Overall, this study confirms that LASiS is an effective method for the formation of kinetically stable nonequilibrium nanoalloys and shows that Au−Co alloy NPs are appealing magnetically responsive plasmonic building blocks for several nanotechnological applications.
Dynamic Effects in Intramolecular Schmidt Reactions: Entropy, Electrostatic Drag, and Selectivity Prediction
Authors: Sun Qing , Lu Xin , Tantillo Dean J.
Published: February 2021

Electrostatic drag in the intramolecular Schmidt reactions of azidopropylcyclohexanones is characterized using density functional theory (DFT) calculations and direct dynamics simulations. Despite resulting from enthalpically favorable interactions, electrostatic drag slows down N2 loss during formation of bridged lactam products, an effect with implications for controlling product selectivity.
Population‐Based Signals of Antidepressant Drug Interactions Associated With Unintentional Traumatic Injury
Authors: Leonard Charles E. , Brensinger Colleen M. , Acton Emily K. , Miano Todd A. , Dawwas Ghadeer K. , Horn John R. , Chung Sophie , Bilker Warren B. , Dublin Sascha , Soprano Samantha E. , Pham Nguyen Thanh Phuong , Manis Melanie M. , Oslin David W. , Wiebe Douglas J. , Hennessy Sean
Published: February 2021

Antidepressants are very widely used and associated with traumatic injury, yet little is known about their potential for harmful drug interactions. We aimed to identify potential drug interaction signals by assessing concomitant medications (precipitant drugs) taken with individual antidepressants (object drugs) that were associated with unintentional traumatic injury. We conducted pharmacoepidemiologic screening of 2000–2015 Optum Clinformatics data, identifying drug interaction signals by performing self‐controlled case series studies for antidepressant + precipitant pairs and injury. We included persons aged 16–90 years codispensed an antidepressant and ≥ 1 precipitant drug(s), with an injury during antidepressant therapy. We classified antidepressant person‐days as either precipitant‐exposed or precipitant‐unexposed. The outcome was an emergency department or inpatient discharge diagnosis for unintentional traumatic injury. We used conditional Poisson regression to calculate confounder adjusted rate ratios (RRs) and accounted for multiple estimation via semi‐Bayes shrinkage. We identified 330,884 new users of antidepressants who experienced an injury. Among such persons, we studied concomitant use of 7,953 antidepressant + precipitant pairs. Two hundred fifty‐six (3.2%) pairs were positively associated with injury and deemed potential drug interaction signals; 22 of these signals had adjusted RRs > 2.00. Adjusted RRs ranged from 1.06 (95% confidence interval: 1.00–1.12, P = 0.04) for citalopram + gabapentin to 3.06 (1.42–6.60) for nefazodone + levonorgestrel. Sixty‐five (25.4%) signals are currently reported in a seminal drug interaction knowledgebase. We identified numerous new population‐based signals of antidepressant drug interactions associated with unintentional traumatic injury. Future studies, intended to test hypotheses, should confirm or refute these potential interactions.
Seed dispersal by carnivores in temperate and tropical dry forests
Authors: Rubalcava‐Castillo Fabián Alejandro , Sosa‐Ramírez Joaquín , Luna‐Ruíz José de Jesús , Valdivia‐Flores Arturo Gerardo , Íñiguez‐Dávalos Luis Ignacio
Published: February 2021

The seed dispersal mechanisms and regeneration of various forest ecosystems can benefit from the actions of carnivores via endozoochory. This study was aimed to evaluate the role of carnivores in endozoochory and diploendozoochory, as well as their effect on seed viability, scarification, and germination in two forest ecosystems: temperate and tropical dry forest. We collected carnivore scat in the Protected Natural Area of Sierra Fría in Aguascalientes, Mexico, for 2 years to determine the abundance and richness of seeds dispersed by each carnivore species, through scat analysis. We assessed seed viability through optical densitometry using X‐rays, analyzed seed scarification by measuring seed coat thickness using a scanning electron microscope, and evaluated seed germination in an experiment as the percentage of seeds germinated per carnivore disperser, plant species, and forest type. In the temperate forest, four plant species (but mainly Arctostaphylos pungens) were dispersed by four mammal species. The gray fox dispersed the highest average number of seeds per scat (66.8 seeds). Bobcat dispersed seeds through diploendozoochory, which was inferred from rabbit (Sylvilagus floridanus) hair detected in their scats. The tropical dry forest presented higher abundance of seeds and richness of dispersed plant species (four species) than in the temperate forest, and the coati dispersed the highest number of seeds (8,639 seeds). Endozoochory and diploendozoochory did not affect viability in thick‐testa seeds (1,480 µm) in temperate forest and thin‐testa seeds (281 µm) in tropical dry forest. Endozoochory improved the selective germination of seeds. Nine plant species were dispersed by endozoochory, but only one species (Juniperus sp.) by diploendozoochory. These results suggest that carnivores can perform an important ecological function by dispersing a great abundance of seeds, scarifying these seeds causing the formation of holes and cracks in the testas without affecting viability, and promoting the selective germination of seeds.
A Flexible and Porous Ferrocene‐Based Gallium MOF with MIL‐53 Architecture
Authors: Benecke Jannik , Fuß Alexander , Engesser Tobias A. , Stock Norbert , Reinsch Helge
Published: February 2021

A new gallium based metal‐organic framework, denoted as Ga‐MIL‐53‐FcDC, with the chemical formula [Ga(OH)(FeC12H8O4)] was synthesized using the ferrocene containing linker molecule 1,1’‐ferrocenedicarboxylic acid (H2FcDC, FeC12H10O4). The porous nature of the compound could be confirmed by nitrogen sorption and a specific surface area of 270 m2/g was determined. The persistence of the ferrocene complex inside the structure was confirmed by Mössbauer‐, EPR and UV/VIS‐spectroscopy. Ga‐MIL‐53‐FcDC shows structural flexibility depending on which guest molecule is located in the pores of the compound. The mechanism of structural flexibility was analyzed by means of powder X‐ray diffraction adsorbing pyrazine or iodine. The flexibility of the crystal structure can be attributed to the torsion of the GaO6 octahedra in the IBU respective to each other and the torsion of the carboxylate groups of FcDC2− relative to the aromatic ring.
Chromic Platinum Complexes Containing Multidentate Ligands
Authors: Soto Miguel A. , Kandel Raksha , MacLachlan Mark J.
Published: February 2021

Platinum(II) complexes display versatile chromic behavior as a consequence of their square planar geometry, which enables intra‐ and intermolecular Pt⋅⋅⋅Pt interactions via open axial coordination sites. These metallophilic interactions are known to generate metal‐metal‐to‐ligand‐charge transfer (MMLCT) transitions, in addition to the ligand‐to‐ligand charge transfer (LLCT) and metal‐to‐ligand‐charge‐transfer (MLCT) transitions that are already present. The electronic properties of such complexes, and consequently the magnitude and intensity of these transitions, can be modulated by various functional groups as well as environmental factors, affording control over the color and luminescence. The responsive behavior of these complexes makes them attractive candidates for chromic devices with applications in memory, encryption, sensors, and optoelectronics. This Minireview summarizes the mechanisms and reversibility of optical chromism in platinum(II) complexes, with a focus on the recent developments in the literature.
Catalytic Synthesis of Dibenzazepines and Dibenzazocines by 7‐Exo‐ and 8‐Endo‐Dig‐Selective Cycloisomerization
Authors: Ito Mamoru , Takaki Asahi , Okamura Moeka , Kanyiva Kyalo Stephen , Shibata Takanori
Published: February 2021

The 7‐exo‐ and 8‐endo‐dig‐selective gold‐catalyzed cycloisomerizations of 2‐propargylamino biphenyl derivatives were developed. The reaction of terminal alkynes gave dibenzo[b,d]azepines by 7‐exo‐dig cycloisomerization. In contrast, when internal alkynes were subjected to the reaction, 8‐endo‐dig cycloisomerization proceeded to provide dibenzo[b,d]azocines. The nucleophilicity at the reaction site and the electron‐withdrawing effect of a tosyl group were important for the present selective transformation. This protocol could be used for ynamide substrates and a silver‐catalyzed reaction gave 7‐exo‐dig products selectively.
Stereoselective Organocatalytic Construction of Spiro Oxindole Pyrrolidines Using Unsaturated α‐Ketoesters and α‐Ketoamides
Authors: Peňaška Tibor , Palchykov Vitalii , Rakovský Erik , Addová Gabriela , Šebesta Radovan
Published: February 2021

We have investigated the stereoselective formation of spiro oxindole pyrrolidines via formal [3+2] cycloaddition of oxindole imines with ketoesters and ketoamides. Bifunctional squaramide organocatalyst was able to induce enantioselectivity of up to 60 % ee, increased to 72 % ee after re‐crystallization, in the formation of spiro pyrrolidines with ketoesters. Interestingly, ketoamides provided alternative spiro oxindole pyrrole products in addition to the main product, which was formed via a different reaction pathway. Structures of spiro oxindole pyrrolidine as well as pyrrole products were confirmed by X‐ray crystallographic analysis. Two new squaramide based catalysts were synthesized and tested. DFT calculation helped elucidate the reaction course.