bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective 1,2‐Aryl‐Aminoalkylation of Alkenes Enabled by Metallaphotoredox Catalysis
Authors: Zheng Songlin , Chen Zimin , Hu Yuanyuan , Xi Xiaoxiang , Liao Zixuan , Li Weirong , Yuan Weiming 
Published: July 2020

AbstractA highly chemo‐ and regioselective intermolecular 1,2‐aryl‐aminoalkylation of alkenes by photoredox/nickel dual catalysis is described here. This three‐component conjunctive cross‐coupling is highlighted by its first application of primary alkyl radicals, which were not compatible in previous reports. The readily prepared α‐silyl amines could be transferred to α‐amino radicals by photo‐induced single electron transfer step. The radical addition/cross‐coupling cascade reaction proceeds under mild, base‐free and redox‐neutral conditions with good functional group tolerance, and importantly, provides an efficient and concise method for the synthesis of structurally valuable α‐aryl substituted γ‐amino acid derivatives motifs.
Electric Field‐Controlled Synthesis and Characterisation of Single Metal–Organic‐Framework (MOF) Nanoparticles
Authors: Morris Peter D. , McPherson Ian J. , Edwards Martin A. , Kashtiban Reza J. , Walton Richard I. , Unwin Patrick R. 
Published: July 2020

AbstractAchieving control over the size distribution of metal–organic‐framework (MOF) nanoparticles is key to biomedical applications and seeding techniques. Electrochemical control over the nanoparticle synthesis of the MOF, HKUST‐1, is achieved using a nanopipette injection method to locally mix Cu2+ salt precursor and benzene‐1,3,5‐tricarboxylate (BTC3−) ligand reagents, to form MOF nanocrystals, and collect and characterise them on a TEM grid. In situ analysis of the size and translocation frequency of HKUST‐1 nanoparticles is demonstrated, using the nanopipette to detect resistive pulses as nanoparticles form. Complementary modelling of mass transport in the electric field, enables particle size to be estimated and explains the feasibility of particular reaction conditions, including inhibitory effects of excess BTC3−. These new methods should be applicable to a variety of MOFs, and scaling up synthesis possible via arrays of nanoscale reaction centres, for example using nanopore membranes.
Stereoselective Oxidative Bioconjugation of Amino Acids and Oligopeptides to Aldehydes
Authors: Tobiesen Henriette N. , Leth Lars A. , Iversen Marc V. , Næsborg Line , Bertelsen Søren , Jørgensen Karl Anker 
Published: July 2020

AbstractThe first stereoselective, near‐equimolar, and metal‐free oxidative bioconjugation of amino acids and oligopeptides to aldehydes is presented. Based on a newly developed organocatalytic oxidative concept, the C‐terminal and side‐chain carboxylic acid functionalities of amino acids and oligopeptides are shown to couple in a stereoselective manner to α‐branched aldehydes catalyzed by a chiral primary amine and a quinone as oxidizing agent. The oxidative coupling generally proceeds in high yield. For aspartic acid, selective coupling of the side‐chain, or the C‐terminal carboxylic acid, is demonstrated depending on the protection strategy. The stereoselective, oxidative bioconjugation concept is extended to a series of oligopeptides where coupling to carboxylic acid functionalities is presented. Bioorthogonal linker molecules for further functionalization are obtained by merging the oxidative coupling strategy with the click concept. It is demonstrated that the configuration of the new stereocenter is determined exclusively by the organocatalyst.
Recoding the Cancer Epigenome by Intervening in Metabolism and Iron Homeostasis with Mitochondria‐Targeted Rhenium(I) Complexes
Authors: Pan Zheng‐Yin , Tan Cai‐Ping , Rao Lu‐Si , Zhang Hang , Zheng Yue , Hao Liang , Ji Liang‐Nian , Mao Zong‐Wan 
Published: July 2020

AbstractThe development and malignancy of cancer cells are closely related to the changes of the epigenome. In this work, a mitochondria‐targeted rhenium(I) complex (DFX‐Re3), integrating the clinical iron chelating agent deferasirox (DFX), has been designed. By relocating iron to the mitochondria and changing the key metabolic species related to epigenetic modifications, DFX‐Re3 can elevate the methylation levels of histone, DNA, and RNA. As a consequence, DFX‐Re3 affects the events related to apoptosis, RNA polymerases, and T‐cell receptor signaling pathways. Finally, it is shown that DFX‐Re3 induces immunogenic apoptotic cell death and exhibits potent antitumor activity in vivo. This study provides a new approach for the design of novel epigenetic drugs that can recode the cancer epigenome by intervening in mitochondrial metabolism and iron homeostasis.
Multiexcitonic Triplet Pair Generation in Oligoacene Dendrimers as Amorphous Solid‐State Miniatures
Authors: Kim Juno , Teo Hao Ting , Hong Yongseok , Oh Juwon , Kim Hyungjun , Chi Chunyan , Kim Dongho 
Published: July 2020

AbstractSinglet fission in organic semiconducting materials has attracted great attention for the potential application in photovoltaic devices. Research interests have been concentrated on identifying working mechanisms of coherent SF processes in crystalline solids as ultrafast SF is hailed for efficient multiexciton generation. However, as long lifetime of multiexcitonic triplet pair in amorphous solids facilitates the decorrelation process for triplet exciton extractions, a precise examination of incoherent SF processes is demanded in delicate model systems to represent heterogeneous structures. Heterogeneous coupling and energetics for SF were developed in our oligoacene dendrimers, which mimic complicated SF dynamics in amorphous solids. SF dynamics in dendritic structures was thoroughly investigated by time‐resolved spectroscopic techniques and quantum chemical calculations in respect of the relative orientation/distance between chromophores and though‐bond/‐space interactions.
Water‐based poly(2‐ethylhexyl acrylate‐itaconic acid) removable adhesives with frost resistance for digital inkjet printing
Authors: Zhang Lei , Bai Yongping , Yin Bin , Peng Hongxia , Ji Changyan , Zhang Wang 
Published: July 2020

AbstractAdhesives are nonmetallic materials used to bond each layer in many applications for its flexibility. For digital inkjet printing, the requirements of adhesives performance are demanding as they must be able to adhere well to adherend, be removable without leaving adhesive residue, or even causing any damage. Water‐based polyacrylates have been widely used for backing adhesive layer in application of digital inkjet printing, due to their various advantages. While the application has been limited on account of the weak frost resistance of common polyacrylates, which could not be used directly under low temperature storage. To improve the weak frost resistance, water‐based poly(2‐ethylhexyl acrylate‐itaconic acid) was synthesized. Itaconic acid (ITA) could be greatly beneficial to improve the frost resistance. The polyacrylates could still be used directly, even after being frozen below at −18°C for 16 hr. The adhesion properties of polyacrylates could also be enhanced by moderate ITA. The results show that the optimal amount of ITA was 2 mass%. The overall properties of the resulting polyacrylates with the 180° peel strength of 2.73 N/25 mm, the tack of 23 #, and the shear holding power of more than 24 hr are suitable for practical applications on removable adhesives for digital inkjet printing.
More than plain text: Censorship deletion in the Chinese social media
Authors: Liu Jun , Zhao Jingyi 
Published: July 2020

AbstractAlthough the Internet allows people to circulate messages using different media, most censorship studies discuss the removal of text content. This article presents a systematic study regarding the censorship of both plain text and multimedia content on the Chinese Internet. By analyzing both censored and surviving posts on the Chinese social media platform Weibo during the 2014 Hong Kong Umbrella Movement, we find that multimedia posts suffered more intensive censorship deletion than plain text posts, with censorship programs being oriented more toward multimedia content like images than the text content of multimedia posts. Our analysis has significant implications for censorship studies, information control, and politics in the “post‐text” era.
Modulation of Crystal Packing via the Tuning of Peripheral Functionality for a Family of Dinuclear Mesocates
Authors: Wilson Benjamin H. , Kruger Paul E. 
Published: July 2020

AbstractA family of four novel pyrazinyl‐hydrazone based ligands have been synthesized with differing functionality at the 5‐position of the central aromatic ring. Previous work has shown such ligands to form dinuclear triple mesocates which pack to form hexagonal channels capable of gas sorption. The effect of the peripheral functionality of the ligand on the crystal packing was investigated by synthesizing complexes 1 to 4 which feature amino, bromo, iodo and methoxy substituents respectively. Complexes 1 to 3 crystallized in the same hexagonal space group P63/m and featured 1D channels. However, on closer inspection while the packing of 1 is mediated by hydrogen bonding interactions, the packing of complexes 2 and 3 are not, due to a subtlety different π–π stacking interaction enforced by the halogen substituent. The more bulky nature of the methoxy substituent of 4 results in the complex crystallizing in the triclinic space group P‐1, featuring an entirely different crystal packing.
Corticomotor reorganization during short‐term visuomotor training in the lower back: A randomized controlled study
Authors: Cavaleri Rocco , Chipchase Lucy S. , Massé‐Alarie Hugo , Schabrun Siobhan M. , Shraim Muath A. , Hodges Paul W. 
Published: July 2020

AbstractIntroductionAccumulating evidence suggests that motor skill training is associated with structural and functional reorganization of the primary motor cortex. However, previous studies have focussed primarily upon the upper limb, and it is unclear whether comparable reorganization occurs following training of other regions, such as the lower back. Although this holds important implications for rehabilitation, no studies have examined corticomotor adaptations following short‐term motor training in the lower back.MethodThe aims of this study were to (a) determine whether a short‐term lumbopelvic tilt visuomotor task induced reorganization of the corticomotor representations of lower back muscles, (b) quantify the variability of corticomotor responses to motor training, and (c) determine whether any improvements in task performance were correlated with corticomotor reorganization. Participants were allocated randomly to perform a lumbopelvic tilt motor training task (n = 15) or a finger abduction control task involving no lumbopelvic movement (n = 15). Transcranial magnetic stimulation was used to map corticomotor representations of the lumbar erector spinae before, during, and after repeated performance of the allocated task.ResultsNo relationship between corticomotor reorganization and improved task performance was identified. Substantial variability was observed in terms of corticomotor responses to motor training, with approximately 50% of participants showing no corticomotor reorganization despite significant improvements in task performance.ConclusionThese findings suggest that short‐term improvements in lower back visuomotor task performance may be driven by changes in remote subcortical and/or spinal networks rather than adaptations in corticomotor pathways. However, further research using tasks of varying complexities and durations is required to confirm this hypothesis.
Risk, resilience, psychological distress, and anxiety at the beginning of the COVID‐19 pandemic in Germany
Authors: Petzold Moritz Bruno , Bendau Antonia , Plag Jens , Pyrkosch Lena , Mascarell Maricic Lea , Betzler Felix , Rogoll Janina , Große Julia , Ströhle Andreas 
Published: July 2020

AbstractBackgroundThe current COVID‐19 pandemic comes with multiple psychological stressors due to health‐related, social, economic, and individual consequences and may cause psychological distress. The aim of this study was to screen the population in Germany for negative impact on mental health in the current COVID‐19 pandemic and to analyze possible risk and protective factors.MethodsA total of 6,509 people took part in an online survey in Germany from 27 March to 6 April. The questionnaire included demographic information and ascertained psychological distress, anxiety and depressive symptoms, and risk and protective factors.ResultsIn our sample, over 50% expressed suffering from anxiety and psychological distress regarding the COVID‐19 pandemic. Participants spent several hours per day thinking about COVID‐19 (M = 4.45). Psychological and social determinants showed stronger associations with anxiety regarding COVID‐19 than experiences with the disease.ConclusionsThe current COVID‐19 pandemic does cause psychological distress, anxiety, and depression for large proportions of the general population. Strategies such as maintaining a healthy lifestyle and social contacts, acceptance of anxiety and negative emotions, fostering self‐efficacy, and information on where to get medical treatment if needed, seem of help, while substance abuse and suppression of anxiety and negative emotions seem to be associated with more psychological burden.
Revealing the synergy of Sn insertion in hematite for next‐generation solar water splitting nanoceramics
Authors: Bedin Karen C. , Freitas Andre L. M. , Tofanello Aryane , Rodríguez‐Gutiérrez Ingrid , Souza Flavio L. 
Published: July 2020

AbstractHematite nanoceramics is considered as one of the most promised materials for photoelectrochemical (PEC) water splitting due to its remarkable characteristics such as low band gap, earth abundant composition and stability. In general, the hematite design over fluorine‐doped tin oxide (FTO) glass substrate involve high thermal treatment to promote its surface activation. As consequence, Sn from FTO substrate is commonly found migrating through the hematite layer. This unintentional Sn species diffusion is often associated with improvements on the photoelectrochemical response. The role played by Sn migrating from FTO against intentionally incorporated during the synthesis process into hematite to boost its performance remain unclear. In this perspective, the complexity of these matters was discussed to reveal the contribution and limiting aspects of each effect on the hematite manufacture. Indeed, a deep comprehension and latest advances on Sn diffusion and incorporation role on hematite led us to find synergistic characteristics between them, indicating economically viable alternatives to design active hematite nanoceramics. Regardless of its morphology, the key direction is based on external modifications which reduce energetic barriers on interfaces to favor electron carrier dynamics.
Advances in Electrochemical Decarboxylative Transformation Reactions
Authors: Ramadoss Velayudham , Zheng Yue , Shao Xiaoqing , Tian Lifang , Wang Yahui 
Published: July 2020

AbstractOwing to their non‐toxic, stable, inexpensive properties, carboxylic acids are considered as environmentally benign alternatives as coupling partners in various organic transformations. Electrochemical mediated decarboxylation of carboxylic acid has emerged as a new and efficient methodology for the construction of carbon‐carbon or carbon‐heteroatom bonds. Compared with transition‐metal catalysis and photoredox catalysis, electro‐organic decarboxylative transformations are considered as a green and sustainable protocol due to the absence of chemical oxidants and strong bases. Further, it exhibits good tolerance with various functional groups. In this Minireview, we summarize the recent advances and discoveries on the electrochemical decarboxylative transformations on C−C and C−heteroatoms bond formations.
Dicarba[26]hexaporphyrinoids(1.1.1.1.1.1) with an Embedded Cyclopentene Moiety—Conformational Switching
Authors: Berlicka Anna , Stanowska Justyna , Białek Michał J. , Ślepokura Katarzyna , Latos‐Grażyński Lechosław 
Published: July 2020

AbstractIncorporation of cyclopentene fragments into a skeleton of parental [26]hexaphyrin(1.1.1.1.1.1) afforded extended carbaporphyrinoids: 31,34‐dicarbahexa[26]chlorin and its derivatives: the first externally substituted by ethoxy and 2,4,6‐trimethylbenzylidene groups and the second one formed by selective oxidation of one cyclopentene ring. Macrocycles adopt dumbbell‐shaped conformations with two meso hydrogen atoms located inside the macrocyclic cavity. Protonation of 31,34‐dicarba[26]hexachlorins provided dications existing in dumbbell‐shaped and rectangular conformations.
Effect of Site‐Specific O‐Glycosylation on the Structural Behavior of NOTCH1 Receptor Extracellular EGF‐like Domains 11 and 10
Authors: Yokoi Yasuhiro , Nishimura Shin‐Ichiro 
Published: July 2020

AbstractHuman NOTCH1 receptor contains 36 epidermal growth factor (EGF)‐like repeating domains, in which O‐glycosylation status of EGF12 domain regulates the interaction with Notch ligands. Our interest is focused on the effect of specific O‐glycosylation states on the structural behavior of EGF11 and EGF10, because they appeared to affect molecular mechanism in receptor–ligand interactions by inducing some conformational alterations in these domains and/or the regions connecting two domains. To understand the structural impact of various O‐glycosylation patterns on the pivotal EGF‐like repeats 10, 11, and 12, we performed chemical synthesis and NMR studies of site‐specifically O‐glycosylated EGF11 and EGF10. Our strategy enabled us to synthesize four EGF11 and five EGF10 modules. The specific O‐glycosylation states affected in vitro folding of EGF10 more than EGF11, while calcium ion had a larger effect on EGF11 folding. Comprehensive NMR studies shed light on the new type “sugar bridges” crosslinking Thr‐O‐GlcNAc in the consensus sequence C5‐X‐X‐G‐X‐(T/S)‐G‐X‐X‐C6 and an amino acid in the hinge region between the domains, 445Thr‐O‐GlcNAc—IIe451 in domain 11 and 405Thr‐O‐GlcNAc—Gln411 in domain 10, respectively.
In Situ Growth of Ultrafine Pt Nanoparticles onto Hierarchical Co3O4 Nanosheet‐Assembled Microflowers for Efficient Electrocatalytic Hydrogen Evolution
Authors: Gu Minyi , Jia Qingyang , Zhu Yanbo , Xu Lin , Tang Yawen 
Published: July 2020

AbstractThe development of Pt‐based electrocatalysts with high Pt utilization efficiency toward the hydrogen evolution reaction (HER) is of great significance for the future sustainable hydrogen economy. For rational design of high‐performance HER electrocatalyst, the simultaneous consideration of both thermodynamic and kinetic aspects remains greatly challenging. Herein, a simple template‐derived strategy is demonstrated for the in situ growth of ultrafine Pt nanoparticles onto Co3O4 nanosheet‐assembled microflowers (abbreviated as Pt/Co3O4 microflowers hereafter) by using the pre‐fabricated PtCo‐based Hofmann coordination polymer as reactive templates. The elaborate preparation of such intriguing hierarchical architecture with well‐dispersed tiny Pt nanoparticles, abundant metal/oxide heterointerfaces and open configuration endows the formed Pt/Co3O4 microflowers with high Pt utilization efficiency, rich active sites, lowered energy barrier for water dissociation and expedited reaction kinetics. Consequently, the Pt/Co3O4 microflowers exhibit superior HER activity with a relatively low overpotential of 34 mV to deliver a current density of 10 mA cm−2, small Tafel slope (34 mV dec−1) and outstanding electrochemical stability, representing an attractive electrocatalyst for practical water splitting. What's more, our concept of in situ construction of metal/oxide heterointerfaces may provide a new opportunity to design high‐performance electrocatalysts for a variety of applications.
Esterase‐Activatable Synthetic M+/Cl− Channel Induces Apoptosis and Disrupts Autophagy in Cancer Cells
Authors: Malla Javid Ahmad , Sharma Virender Kumar , Lahiri Mayurika , Talukdar Pinaki 
Published: July 2020

AbstractThe formation of a supramolecular synthetic M+/Cl− channel in the membrane phospholipid bilayer has been reported upon activation of a methyl pivalate‐linked N1,N3‐dialkyl‐2‐hydroxyisophthalamide by esterases. The channel formation induces apoptosis in cancer cells via the intrinsic pathway. Interestingly, the supramolecular channel was also shown to disrupt autophagy in cancer cells by causing alkalization of lysosomes – a feature that has been confirmed at the cellular and protein level.
Copula‐based predictions in small area estimation
Authors: Grover Kanika , Acar Elif F. , Torabi Mahmoud 
Published: July 2020

AbstractUnit‐level regression models are commonly used in small area estimation (SAE) to obtain an empirical best linear unbiased prediction of small area characteristics. The underlying assumptions of these models, however, may be unrealistic in some applications. Previous work developed a copula‐based SAE model where the empirical Kendall's tau was used to estimate the dependence between two units from the same area. In this article, we propose a likelihood framework to estimate the intra‐class dependence of the multivariate exchangeable copula for the empirical best unbiased prediction (EBUP) of small area means. One appeal of the proposed approach lies in its accommodation of both parametric and semi‐parametric estimation approaches. Under each estimation method, we further propose a bootstrap approach to obtain a nearly unbiased estimator of the mean squared prediction error of the EBUP of small area means. The performance of the proposed methods is evaluated through simulation studies and also by a real data application.
Estrogen receptor alpha, G‐protein coupled estrogen receptor 1, and aromatase: Developmental, sex, and region‐specific differences across the rat caudate–putamen, nucleus accumbens core and shell
Authors: Krentzel Amanda A. , Willett Jaime A. , Johnson Ashlyn G. , Meitzen John 
Published: July 2020

AbstractSex steroid hormones such as 17β‐estradiol (estradiol) regulate neuronal function by binding to estrogen receptors (ERs), including ERα and GPER1, and through differential production via the enzyme aromatase. ERs and aromatase are expressed across the nervous system, including in the striatal brain regions. These regions, comprising the nucleus accumbens core, shell, and caudate–putamen, are instrumental for a wide‐range of functions and disorders that show sex differences in phenotype and/or incidence. Sex‐specific estrogen action is an integral component for generating these sex differences. A distinctive feature of the striatal regions is that in adulthood neurons exclusively express membrane but not nuclear ERs. This long‐standing finding dominates models of estrogen action in striatal regions. However, the developmental etiology of ER and aromatase cellular expression in female and male striatum is unknown. This omission in knowledge is important to address, as developmental stage influences cellular estrogenic mechanisms. Thus, ERα, GPER1, and aromatase cellular immunoreactivity was assessed in perinatal, prepubertal, and adult female and male rats. We tested the hypothesis that ERα, GPER1, and aromatase exhibits sex, region, and age‐specific differences, including nuclear expression. ERα exhibits nuclear expression in all three striatal regions before adulthood and disappears in a region‐ and sex‐specific time‐course. Cellular GPER1 expression decreases during development in a region‐ but not sex‐specific time‐course, resulting in extranuclear expression by adulthood. Somatic aromatase expression presents at prepuberty and increases by adulthood in a region‐ but not sex‐specific time‐course. These data indicate that developmental period exerts critical sex‐specific influences on striatal cellular estrogenic mechanisms.