bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Computational Studies towards Chemoselective C−F over C−Cl Functionalisation: Reversible Oxidative Addition is the Key
Authors: Jacobs Emily , Keaveney Sinead T. 
Published: October 2020

AbstractCatalytic cross‐coupling is a valuable tool for forming new carbon‐carbon and carbon‐heteroatom bonds, allowing access to a variety of structurally diverse compounds. However, for this methodology to reach its full potential, precise control over all competing cross‐coupling sites in poly‐functionalised building blocks is required. Carbon‐fluorine bonds are one of the most stable bonds in organic chemistry, with oxidative addition at C−F being much more difficult than at other C‐halide bonds. As such, the development of methods to chemoselectively functionalise the C−F position in poly‐halogenated arenes would be very challenging if selectivity was to be induced at the oxidative addition step. However, metal‐halide complexes exhibit different trends in reactivity to the parent haloarenes, with metal‐fluoride complexes known to be very reactive towards transmetalation. In this current work we sought to exploit the divergent reactivity of Ni−Cl and Ni−F intermediates to develop a chemoselective C−F functionalisation protocol, where selectivity is controlled by the transmetalation step. Our experimental studies highlight that such an approach is feasible, with a number of nickel catalysts shown to facilitate Hiyama cross‐coupling of 1‐fluoronapthalene under base free conditions, while no cross‐coupling with 1‐chloronapthalene occurred. Computational and experimental studies revealed the importance of reversible C−Cl oxidative addition for the development of selective C−F functionalisation, with ligand effects on the potential for reversibility also presented.
Interface Amorphization of Two‐Dimensional Black Phosphorus upon Treatment with Diazonium Salts
Authors: Mitrović Aleksandra , Wild Stefan , Lloret Vicent , Fickert Michael , Assebban Mhamed , Márkus Bence G. , Simon Ferenc , Hauke Frank , Abellán Gonzalo , Hirsch Andreas 
Published: October 2020

AbstractTwo‐dimensional (2D) black phosphorus (BP) represents one of the most appealing 2D materials due to its electronic, optical, and chemical properties. Many strategies have been pursued to face its environmental instability, covalent functionalization being one of the most promising. However, the extremely low functionalization degrees and the limitations in proving the nature of the covalent functionalization still represent challenges in many of these sheet architectures reported to date. Here we shine light on the structural evolution of 2D‐BP upon the addition of electrophilic diazonium salts. We demonstrated the absence of covalent functionalization in both the neutral and the reductive routes, observing in the latter case an unexpected interface conversion of BP to red phosphorus (RP), as characterized by Raman, 31P‐MAS NMR, and X‐ray photoelectron spectroscopies (XPS). Furthermore, thermogravimetric analysis coupled to gas chromatography and mass spectrometry (TG‐GC‐MS), as well as electron paramagnetic resonance (EPR) gave insights into the potential underlying radical mechanism, suggesting a Sandmeyer‐like reaction.
Mimicking Biological Recognition: Lessons in Binding Hydrophilic Guests in Water
Authors: Ferguson Johns Hannah P. , Harrison Emily E. , Stingley Kyla J. , Waters Marcey L. 
Published: October 2020

AbstractSelective molecular recognition of hydrophilic guests in water plays a fundamental role in a vast number of biological processes, but synthetic mimicry of biomolecular recognition in water still proves challenging both in terms of achieving comparable affinities and selectivities. This Review highlights strategies that have been developed in the field of supramolecular chemistry to selectively and non‐covalently bind three classes of biologically relevant molecules: nucleotides, carbohydrates, and amino acids. As several groups have systematically modified receptors for a specific guest, an evolutionary perspective is also provided in some cases. Trends in the most effective binding forces for each class are described, providing insight into selectivity and potential directions for future work.
A Promising Approach for Controlling the Second Coordination Sphere of Biomimetic Metal Complexes: Encapsulation in a Dynamic Hydrogen‐Bonded Capsule
Authors: Zhang Tongtong , Le Corre Laurent , Reinaud Olivia , Colasson Benoit 
Published: October 2020

AbstractThe design of biomimetic models of metalloenzymes needs to take into account many factors and is therefore a challenging task. We propose in this work an original strategy to control the second coordination sphere of a metal centre and its distal environment. A biomimetic complex, reproducing the first coordination sphere, is encapsulated in a self‐assembled hydrogen‐bonded capsule. The cationic complex is co‐encapsulated with its counter‐anion or with solvent molecules. The capsule is dynamic, allowing a fast in/out exchange of the co‐encapsulated species. It also provides both a hydrogen‐bonding site in the second coordination sphere and a source of proton as it can be deprotonated in the presence of the complex, providing a globally neutral host‐guest assembly. This simple and broad scope strategy is unprecedented in biomimetic studies. The approach appears to be a very promising method for the stabilisation of reactive species and for the study of their reactivity.
Reappraisal of Empirical Solvent Polarity Scales for Organic Solvents
Authors: Spange Stefan , Weiß Nadine , Schmidt Caroline H. , Schreiter Katja 
Published: October 2020

AbstractCorrelations of Reichardt'sET(30), the CatalánSdP(solvent dipolarity),SP(solvent polarizability),SA(solvent acidity),SB(solvent basicity), Kamlet‐Taftπ* (dipolarity/polarizability),α(hydrogen bond donating ability) andβ(hydrogen bond accepting ability) polarity parameters with the molar concentration of 161 pure organic solvents are presented. Mostly, linear relationships of the polarity parameter as a function of molar concentration are obtained as long as each individual solvent class is considered separately. A physically different interpretation of theET(30), Kamlet‐Taftπ* andαas well as CatalánSAandSBparameters has been proposed. Furthermore, the Hildebrand solubility parameter in combination with the diffraction index is used for the correlation analysis with the above‐mentioned solvent parameters. It can be concluded that empirical polarity parameters derived from solvatochromic UV/Vis measurements are inherently a function of the molecular structure of the probe.
Color difference classification of dyed fabrics via a kernel extreme learning machine based on an improved grasshopper optimization algorithm
Authors: Li Jianqiang , Shi Weimin , Yang Donghe 
Published: October 2020

AbstractConventional artificial color difference detection is error prone and inefficient. Herein, a novel color difference classification model is proposed for dyed fabrics via a kernel extreme learning machine based on an improved grasshopper optimization algorithm. First, in order to prevent the grasshopper optimization algorithm from succumbing to local optimality, it is proposed to optimize the initial population of the algorithm using differential evolution, resulting in a better solution direction at the outset. Then, this novel grasshopper algorithm is used to adjust the kernel bandwidth and penalty parameters of the learning maching model, thereby forming a color difference classification model for dyed fabrics based on the differential evolution grasshopper optimization algorithm kernel extreme learning machine. Finally, the key indicator values representing color difference are extracted from the printed and dyed product images collected under the standard light source. The color difference calculated by substituting these values into the color difference formula generates a color difference dataset, which is used to train and test the color difference classification model. Experimental results show that the proposed differential evolution grasshopper optimization algorithm kernel extreme learning machine model has high classification accuracy and impressive stability. The average classification accuracy of the proposed model is 98.89%, whereas the accuracy of kernel extreme learning machine is only 91.08%.
More Sustainable Chemical Activation Strategies for the Production of Porous Carbons
Authors: Sevilla Marta , Díez Noel , Fuertes Antonio B. 
Published: October 2020

AbstractThe preparation of porous carbons attracts a great deal of attention given the importance of these materials in many emerging applications, such as hydrogen storage, CO2 capture, and energy storage in supercapacitors and batteries. In particular, porous carbons produced by applying chemical activation methods are preferred because of the high pore development achieved. However, given the environmental risks associated with conventional activating agents such as KOH, the development of greener chemical activation methodologies is an important objective. This Review summarizes recent progress in the production of porous carbons by using more sustainable strategies based on chemical activation. The use of less‐corrosive chemical agents as an alternative to KOH is thoroughly reviewed. In addition, progress achieved to date by using emerging self‐activation methodologies applied to organic salts and biomass products is also discussed.
The “sugar‐coated bullets” of cancer: Tumor‐derived exosome surface glycosylation from basic knowledge to applications
Authors: Lin Shanyi , Zhou Shumin , Yuan Ting 
Published: October 2020

AbstractScientific interest in exosomes has exploded in recent decades. In 1990 only three articles were published on exosomes, while over 1,700 have already been published half‐way into 2020.1 While researchers have shown much interest in exosomes since being discovered in 1981, an appreciation of the potential role of glycans in exosome structure and function has emerged only recently. Glycosylation is one of the most common post‐translational modification, which functions in many physiological and pathological aspects of cellular function. Many components of exosomes are heavily glycosylated including proteins, lipids, among others. Thus, glycosylation undoubtedly has a great impact on exosome biosynthesis and function. Despite the importance of glycosylation in exosomes and the recent recognition of them as biomarkers for not only malignancies but also other system dysfunction and disease, the characterization of exosome glycans remains understudied. In this review, we discuss glycosylation patterns of exosomes derived from various tissues, their biological features, and potential for various clinical applications. We highlight state‐of‐the‐art knowledge about the fine structure of exosomes, which will allow researchers to reconstruct them by surface modification. These efforts will likely lead to novel disease‐related biomarker discovery, purification tagging, and targeted drug transfer for clinical applications in the future.
Using LiDAR to assess transitions in riparian vegetation structure along a rural‐to‐urban land use gradient in western North America
Authors: Grijseels Noortje H. , Buchert Martin , Brooks Paul D. , Pataki Diane E. 
Published: October 2020

AbstractRiparian forests are essential for stream ecological processes in arid and semiarid regions, however, they are often highly altered by the rapid expansion of urban areas. To maintain riparian ecosystems services, it is important to better understand the effects of urbanization on riparian forests. We quantified the three‐dimensional (3D) structure and woody species composition of a riparian corridor in Utah, USA, to evaluate patterns of vegetation along stream reaches that flow through distinct hydrologic domains (with gaining and losing reaches) and through a rapid rural‐to‐urban gradient. By using LiDAR imaging and field observations, we explore the extent to which the riparian vegetation structure follows patterns of topography linked to energy and water subsidies and patterns of human influence along the stream. Whereas natural reaches of Red Butte Creek were characterized by native vegetation and typical riparian species (e.g., Betula occidentalis), urbanized reaches had higher numbers of introduced plants (e.g., Acer platanoides) and more upland species (e.g., Quercus gambelii). Urban reaches were also characterized by exceptionally high trees (>18 m) in older residential neighbourhoods. In the natural area, canopy height was negatively correlated with height above the river (HAR). Additionally, we found higher cover and taller canopies on north‐facing aspects. These results show that LiDAR data, in combination with ground observations, can reveal strong influences of hydrology as well as land use in different canopy layers of riparian forests. We suggest that the decision making of individual landowners shapes vegetation beyond natural hydrological patterns, with implications for riparian forest management and restoration.
Polycentric to monocentric governance: Power dynamics in Lake Victoria's fisheries
Authors: Mudliar Pranietha 
Published: October 2020

AbstractIn theory, polycentric governance arrangements are better able to respond to complex, uncertain, and multiscale challenges. Research on polycentric governance challenges these normative assumptions to find that the functionality of polycentric systems is constrained because different kinds of power influence not only the emergence and design of polycentric systems, but also decisions about policy choices and outcomes. This study uses a polycentric power typology to provide insights into the power dynamics underpinning the polycentric fisheries system of Lake Victoria through qualitative case study methods. The study reveals that power by design creates a polycentric structure that could potentially provide opportunities for power‐sharing between higher and lower decision centers. However, pragmatic and framing power erode power away from lower‐level authorities by either taking over or dismantling lower‐level decision centers and institutions. Without a genuine intent to share power among decision centers, cross‐level linkages are deliberately nonfunctional or have high transaction costs, creating and intensifying conflicts and competitions between the state and local governments. In the absence of functional cross‐linkages, information‐sharing, accountability, and conflict‐resolution mechanisms are hampered as is the inclusion of lower‐level actors in management. Higher‐level actors justify taking over functions of lower‐level actors by deploying frames of the lower‐level's “lack of capacity.” In combination, these factors concentrate power at the center, resulting in maladaptive outcomes in Lake Victoria's fisheries. The findings suggest that improving understanding of contextual conditions that are more suited to polycentric governance is important for refining theory and improving governance.
Proteomic exploration of common pathophysiological pathways in diabetes and cardiovascular disease
Authors: Molvin John , Jujić Amra , Melander Olle , Pareek Manan , Råstam Lennart , Lindblad Ulf , Daka Bledar , Leósdóttir Margrét , Nilsson Peter M. , Olsen Michael H. , Magnusson Martin 
Published: October 2020

AbstractAimsThe epidemiological association between diabetes and cardiovascular disease is well established, but the pathophysiological link is complex and multifactorial. We investigated seven proteins, previously linked to incident diabetes mellitus, and their association with cardiovascular disease and mortality.Methods and resultsPlasma samples from 1713 individuals from the Swedish population‐based Malmö Preventive Project (mean age 67.4 ± 6.0 years; 29.1% women) were analysed with a proximity extension assay panel. Seven proteins [scavenger receptor cysteine rich type 1 protein M130 (CD163), fatty acid‐binding protein 4 (FABP4), plasminogen activator inhibitor 1 (PAI), insulin‐like growth factor‐binding protein 2 (IGFB2), cathepsin D (CTSD), galectin‐4 (GAL4), and paraoxonase‐3 (PON3)] previously shown to be associated with incident diabetes were analysed for associations with all‐cause mortality (ACM), cardiovascular mortality (CVM), incident coronary events (CEs), and incident heart failure (HF). After exclusion of prevalent cases of respective outcome, proteins that met Bonferroni‐corrected significance were analysed in multivariable Cox regression models. Significant associations were identified between five proteins [GAL4 (hazard ratio; 95% confidence interval: 1.17–1.41), CTSD (1.15–1.37), CD163 (1.09–1.30), IGFBP2 (1.05–1.30), and FABP4 (1.04–1.29)] and ACM and four proteins [GAL4 (1.38–1.56), CTSD (1.14–1.43), CD163 (1.09–1.36), and IGFBP2 (1.03–1.35)] with CVM. Three proteins [GAL4 (1.14–1.57), CTSD (1.12–1.50), and FABP4 (1.05–1.55)] were significantly associated with incident CE and two [GAL4 (1.03–1.54) and CTSD (1.01–1.46)] were associated with incident HF after adjusting for traditional risk factors including N‐terminal pro‐brain natriuretic peptide.ConclusionsIn a general Swedish population, four proteins previously shown to be associated with diabetes were associated with ACM and CVM. Three proteins were associated with incident CE. Finally, GAL4 and CTSD displayed novel associations with incident HF and were the only proteins associated with all outcomes.
Parent of origin gene expression in the bumblebee,Bombus terrestris, supports Haig's kinship theory for the evolution of genomic imprinting
Authors: Marshall Hollie , van Zweden Jelle S. , Van Geystelen Anneleen , Benaets Kristof , Wäckers Felix , Mallon Eamonn B. , Wenseleers Tom 
Published: October 2020

AbstractGenomic imprinting is the differential expression alleles in diploid individuals, with the expression being dependent on the sex of the parent from which it was inherited. Haig's kinship theory hypothesizes that genomic imprinting is due to an evolutionary conflict of interest between alleles from the mother and father. In social insects, it has been suggested that genomic imprinting should be widespread. One recent study identified parent-of-origin expression in honey bees and found evidence supporting the kinship theory. However, little is known about genomic imprinting in insects and multiple theoretical predictions must be tested to avoid single-study confirmation bias. We, therefore, tested for parent-of-origin expression in a primitively eusocial bee. We found equal numbers of maternally and paternally biased expressed genes. The most highly biased genes were maternally expressed, offering support for the kinship theory. We also found low conservation of potentially imprinted genes with the honey bee, suggesting rapid evolution of genomic imprinting in Hymenoptera.
Alterations of brain activity and functional connectivity in transition from acute to chronic tinnitus
Authors: Lan Liping , Li Jiahong , Chen Yanhong , Chen Wan , Li Wenrui , Zhao Fei , Chen Guisheng , Liu Jiahao , Chen Yuchen , Li Yuanqing , Wang Chang‐Dong , Zheng Yiqing , Cai Yuexin 
Published: October 2020

AbstractThe objective of this study was to investigate alterations to brain activity and functional connectivity in patients with tinnitus, exploring neural features in the transition from acute to chronic phantom perception. Twenty‐four patients with acute tinnitus, 23 patients with chronic tinnitus, and 32 healthy controls were recruited. High‐density electroencephalography (EEG) was used to explore changes in brain areas and functional connectivity in different groups. When compared with healthy subjects, acute tinnitus patients had a significant reduction in superior frontal cortex activity across all frequency bands, whereas chronic tinnitus patients had a significant reduction in the superior frontal cortex at beta 3 and gamma frequency bands as well as a significant increase in the inferior frontal cortex at delta‐band and superior temporal cortex at alpha 1 frequency band. When compared to the chronic tinnitus group, the acute tinnitus group activity was significantly increased in the middle frontal and parietal gyrus at the gamma‐band. Functional connectivity analysis showed that the chronic tinnitus group had increased connections between the parahippocampus gyrus, posterior cingulate cortex, and precuneus when compared with the healthy group. Alterations of local brain activity and connections between the parahippocampus gyrus and other nonauditory areas appeared in the transition from acute to chronic tinnitus. This indicates that the appearance and development of tinnitus is a dynamic process involving aberrant local neural activity and abnormal connectivity in multifunctional brain networks.
Modelling the impact of audit/remuneration committee overlap on debtholders' perceptions of accounting information quality: The role of CEO power
Authors: Al‐Dhamari Redhwan , Alquhaif Abdulsalam Saad , Al‐Gamrh Bakr Ali 
Published: October 2020

AbstractThis study examines how debtholders perceive accounting information quality of firms with audit committee members who are also on the remuneration committee, and whether strong CEO power enhances or undermines the governance role of overlapping committees. Using 841 observations of Malaysian firms over the period 2013–2015, we find that firms with overlapping audit and remuneration committees are perceived by debtholders to be transparent and of lower operating risk and, consequently, be associated with lower cost of debt. We also find that the beneficial effect of the presence of overlapping committees is weakened by the level of CEO power. Our results are robust to concerns of endogeneity and alternative measurers of the key variables. This study is timely in light of recently increasing call for the broadening of audit committee members' understanding of business strategies, risks and incentives provided by firms' executive compensation structures. Our study also contributes to the ongoing debate surrounding CEO power by suggesting that debtholders perceive potent CEO power as detrimental to their investments and thus charge higher interest rates from firms with powerful CEOs and overlapping directors.
Comparison of toxicity of Ti3C2 and Nb2C Mxene quantum dots (QDs) to human umbilical vein endothelial cells
Authors: Gu Manyu , Dai Zhiqi , Yan Xiang , Ma Junfei , Niu Yingchun , Lan Wenjie , Wang Xin , Xu Quan 
Published: October 2020

AbstractRecently, we developed highly fluorescent Ti3C2 and Nb2C Mxene quantum dots (QDs) for labeling of in vitro models. However, the mechanism of the toxicity of the prepared QDs was not explored before. In this study, we addressed the possible mechanism associated with cytotoxicity of the QDs to human umbilical vein endothelial cells (HUVECs). Exposure to up to 100 μg/ml Ti3C2 but not Nb2C QDs for 24 h significantly induced cytotoxicity. The exposure also increased intracellular Ti and Nb elements, indicating the internalization of both types of QDs. None of the QDs promoted interleukin 6 (IL‐6) and IL‐8 releases. Rather, Ti3C2 QDs significantly reduced IL‐6 and IL‐8 release, indicating that the toxicity of Ti3C2 QDs was not due to elevated inflammatory responses. Exposure to Ti3C2 but not Nb2C QDs resulted in increased LC3B‐II/I ratio and beclin‐1 proteins, biomarkers of autophagy, as well as the accumulation of autophagic substance p62. Ti3C2 QDs also more effectively promoted pro‐caspase 3 but not pro‐caspase 8 compared with Nb2C QDs. Furthermore, pre‐treatment with autophagic modulators altered the cytotoxicity of Ti3C2 QDs, which further confirmed the role of autophagic dysfunction in Ti3C2 QD‐induced toxicity to HUVECs. In conclusion, the results from this study suggested that high levels of Ti3C2 QDs could induce cytotoxicity to HUVECs by inducing the dysfunction of autophagy. Nb2C QDs appeared to be more biocompatible to HUVECs compared with Ti3C2 QDs at the same mass concentrations, which suggested a role of composition of Mxene QDs to determine their toxicity to human endothelial cells.