bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vorhersage stickstoffbasierter Verbindungsklassen: Guanidinate TCN3 (T=V, Nb, Ta) und Orthonitridocarbonate T′2CN4 (T′=Ti, Zr, Hf) von Übergangsmetallen
Authors: Luo Dongbao , Qiao Xianji , Dronskowski Richard 
Published: October 2020

AbstractWegen der einzigartigen Fähigkeit des Kohlenstoffs, verschiedenste sp‐Hybridisierungen oder Orbitalmischungen auszubilden, kann er in unterschiedlichen komplexen Anionen wie der bekannten Carbodiimideinheit NCN2−, dem bis dato unbekannten CN35−‐Guanidinatanion und dem ebenso neuartigen CN48−‐Orthonitridocarbonat (onc) vorliegen und insofern das Feld bekannter stickstoffbasierter Festkörperverbindungen erweitern. Die beiden letztgenannten komplexen Anionen, bislang noch unbekannt, wurden von uns mittels voraussetzungsfreier Struktursuchverfahren hinsichtlich ihrer Chemie modelliert, so dass wir hier die Existenz der ersten bei Normaldruck mechanisch stabilen wasserstofffreien Guanidinate TCN3 (T=V, Nb, Ta) und Orthonitridocarbonate T′2CN4 (T′=Ti, Zr, Hf) vorhersagen; die letztgenannte Anionenklasse dürfte in festen Lösungen mit den stöchiometrisch gleichen Nitridocarbodiimiden und Nitridoguanidinaten koexistieren. Zudem schlagen wir thermodynamisch günstige exotherme Reaktionen als Richtschnur für ihre Synthesen vor und legen nahe, dass der Zerfall dieser neuen Verbindungen aufgrund vermutlich hoher kinetischer Barrieren (Aufbrechen der C‐N‐Bindung) und durchaus erheblicher Madelungenergien, die die stark geladenen komplexen Ionen stabilisieren, unwahrscheinlich ist. Während chemische Bindungsanalysen eine kovalentere Bindungssituation im neu entdeckten CN48−‐Anion im Vergleich zu NCN2− und CN35− bei artverwandten Verbindungen aufdecken, deuten weitere elektronentheoretische Befunde dieser onc‐Phasen denkbare Anwendungen hinsichtlich ihrer physikochemischen Eigenschaften in den Bereichen der photoelektrochemischen Wasserspaltung sowie der nichtlinearen Optik an.
Kontrolle des intramolekularen Förster‐Resonanzenergietransfers und der Singulettspaltung in einem Subporphyrazin‐Pentacen‐Konjugat mittels Lösungsmittelpolarität
Authors: Guzmán David , Papadopoulos Ilias , Lavarda Giulia , Rami Parisa R. , Tykwinski Rik R. , Rodríguez‐Morgade M. Salomé , Guldi Dirk M. , Torres Tomás 
Published: October 2020

AbstractAufgrund seiner komplementären Absorptionen im Bereich von 450 bis 600 nm wurde ein energiespendendes Hexaarylsubporphyrazin an ein Pentacendimer gebunden, das hauptsächlich als Energieakzeptor und sekundär als Singulettspaltungsaktivierer fungiert. Im entsprechenden Konjugat ist der effiziente intramolekulare Förster‐Resonanzenergietransfer (i‐FRET) der Modus Operandi zur Energieübertragung vom Subporphyrazin auf das Pentacendimer. Beim Energietransfer unterliegt das Pentacendimer einer intramolekularen Singulettspaltung (intramolecular singlet fission, i‐SF), das heißt, der angeregte Singulettzustand wird über einen Zwischenzustand in ein Paar korrelierter Triplettzustände umgewandelt. Die solvatochrome Fluoreszenz des Subporphyrazins ist ein Schlüsselmerkmal dieses Systems und weist in polaren Medien eine Rotverschiebung von bis zu 20 nm auf. Das Lösungsmittel wird daher verwendet, um die spektrale Überlappung zwischen der Fluoreszenz von Subporphyrazin und der Absorption des Pentacendimers zu modulieren, welches einerseits die Förster‐Geschwindigkeitskonstante und andererseits die Triplettquantenausbeute steuert. Die optimale spektrale Überlappung wird in Xylol erzielt, was zu einer Förster‐Geschwindigkeitskonstante von 3.52×1011 s−1 und einer Triplettquantenausbeute von 171 % ±10 % führt. Kurz gesagt, die Abhängigkeit der Lösungsmittelpolarität, die ein einzigartiges Merkmal von Subporphyrazinen ist, ist entscheidend für die Anpassung der spektralen Überlappung, die Gewährleistung einer beträchtlichen Förster‐Geschwindigkeitskonstante und die Maximierung der Triplettquantenausbeuten. Diese Optimierung kann in einzigartiger Weise erreicht werden, ohne dass eine synthetische Modifikation des Subporphyrazindonors erforderlich ist.
Engineering Atomically Dispersed FeN4 Active Sites for CO2 Electroreduction
Authors: Mohd Adli Nadia , Shan Weitao , Hwang Sooyeon , Samarakoon Widitha , Karakalos Stavros , Li Yi , Cullen David A. , Su Dong , Feng Zhenxing , Wang Guofeng , Wu Gang 
Published: October 2020

AbstractAtomically dispersed FeN4 active sites have exhibited exceptional catalytic activity and selectivity for the electrochemical CO2 reduction reaction (CO2RR) to CO. However, the understanding behind the intrinsic and morphological factors contributing to the catalytic properties of FeN4 sites is still lacking. By using a Fe‐N‐C model catalyst derived from the ZIF‐8, we deconvoluted three key morphological and structural elements of FeN4 sites, including particle sizes of catalysts, Fe content, and Fe−N bond structures. Their respective impacts on the CO2RR were comprehensively elucidated. Engineering the particle size and Fe doping is critical to control extrinsic morphological factors of FeN4 sites for optimal porosity, electrochemically active surface areas, and the graphitization of the carbon support. In contrast, the intrinsic activity of FeN4 sites was only tunable by varying thermal activation temperatures during the formation of FeN4 sites, which impacted the length of the Fe−N bonds and the local strains. The structural evolution of Fe−N bonds was examined at the atomic level. First‐principles calculations further elucidated the origin of intrinsic activity improvement associated with the optimal local strain of the Fe−N bond.
Molecular Machine Learning: The Future of Synthetic Chemistry?
Authors: Pflüger Philipp M. , Glorius Frank 
Published: October 2020

AbstractDuring the last decade, modern machine learning has found its way into synthetic chemistry. Some long‐standing challenges, such as computer‐aided synthesis planning (CASP), have been successfully addressed, while other issues have barely been touched. This Viewpoint poses the question of whether current trends can persist in the long term and identifies factors that may lead to an (un)productive development. Thereby, specific risks of molecular machine learning (MML) are discussed. Furthermore, possible sustainable developments are suggested, such as explainable artificial intelligence (exAI) for synthetic chemistry. This Viewpoint will illuminate chances for possible newcomers and aims to guide the community into a discussion about current as well as future trends.
Light‐Promoted Organic Transformations Utilizing Carbon‐Based Gas Molecules as Feedstocks
Authors: Cai Bin , Cheo Han Wen , Liu Tao , Wu Jie 
Published: October 2020

AbstractCarbon‐based gas molecules are readily available feedstocks and are widely used in industry as building blocks or fuels. However, their application in the synthesis of fine chemicals has been hampered due to operational complexity, poor reaction efficiency and selectivity. Recent development of photoredox‐promoted transformations using such gaseous reagents has received considerable attention from the synthetic community. In this review, efforts in developing light‐promoted organic transformations using carbon‐based natural gases as C1 or C2 feedstocks and to overcome the associated challenges are briefly summarized.
Controlling Intramolecular Förster Resonance Energy Transfer and Singlet Fission in a Subporphyrazine–Pentacene Conjugate by Solvent Polarity
Authors: Guzmán David , Papadopoulos Ilias , Lavarda Giulia , Rami Parisa R. , Tykwinski Rik R. , Rodríguez‐Morgade M. Salomé , Guldi Dirk M. , Torres Tomás 
Published: October 2020

AbstractDue its complementary absorptions in the range of 450 and 600 nm, an energy‐donating hexaaryl‐subporphyrazine has been linked to a pentacene dimer, which acts primarily as an energy acceptor and secondarily as a singlet fission enabler. In the corresponding conjugate, efficient intramolecular Förster resonance energy transfer (i‐FRET) is the modus operandi to transfer energy from the subporphyrazine to the pentacene dimer. Upon energy transfer, the pentacene dimer undergoes intramolecular singlet fission (i‐SF), that is, converting the singlet excited state, via an intermediate state, into a pair of correlated triplet excited states. Solvatochromic fluorescence of the subporphyrazine is a key feature of this system and features a red‐shift as large as 20 nm in polar media. Solvent is thus used to modulate spectral overlap between the fluorescence of subporphyrazine and absorption of the pentacene dimer, which controls the Förster rate constant, on one hand, and the triplet quantum yield, on the other hand. The optimum spectral overlap is realized in xylene, leading to Förster rate constant of 3.52×1011 s−1 and a triplet quantum yield of 171 % ±10 %. In short, the solvent polarity dependence, which is a unique feature of subporphyrazines, is decisive in terms of adjusting spectral overlap, ensuring a sizable Förster rate constant, and maximizing triplet quantum yields. Uniquely, this optimization can be achieved without a need for synthetic modification of the subporphyrazine donor.
The impact of extreme skull morphology in domestic dogs on cribriform plate shape
Authors: Jacquemetton Christiane , Drexler Abigail , Kellerman Gavin , Bird Deborah , Van Valkenburgh Blaire 
Published: October 2020

AbstractDog owners are often impressed by their dog's sense of smell. Many of these dogs, however, have skulls that are quite altered from those of their closest canid relatives. Housed within these skulls are essential olfactory structures like the cribriform plate that play a role in olfaction and the transmission of olfactory nerve impulses to the olfactory bulb of the brain. With improvements in CT technology and accessibility, we are now able to digitally reconstruct in 3D cribriform plate morphology and study its variation within and among species. In this study, we CT scanned the skulls of 95 dog specimens from 45 different domestic dog breeds and 12 species of wild canid and compared the shape of the cribriform plate among three main groups: domestic dog breeds, wolf‐like canids, and fox‐like canids. Despite only recent selective pressure for extreme skull morphology, domestic dogs display much more variation in cribriform plate shape than wild canids, indicating that cribriform plate shape is plastic and linked to skull shape. Intense artificial selection on domestic dog skull phenotype in the last 200 years has clear effects on secondary features of the domestic dog skull, implying that selection for overt phenotypes also can impact other anatomical features associated with the skull, like the cribriform plate.
Dissecting the Cellular Mechanism of Prostacyclin Analog Iloprost in Reversing Vascular Dysfunction in Scleroderma
Authors: Tsou Pei‐Suen , Palisoc Pamela J. , Flavahan Nicholas A. , Khanna Dinesh 
Published: October 2020

ObjectiveIntravenous iloprost improves Raynaud’s phenomenon (RP) and promotes healing of digital ulcers in systemic sclerosis (SSc; scleroderma). Despite a short half‐life, its clinical efficacy lasts weeks. Endothelial adherens junctions, which are formed by VE‐cadherin clustering between endothelial cells (ECs), regulate endothelial properties including barrier function, endothelial‐to‐mesenchymal transition (EndoMT), and angiogenesis. We undertook this study to investigate the hypothesis that junctional disruption contributes to vascular dysfunction in SSc, and that the protective effect of iloprost is mediated by strengthening of those junctions.MethodsDermal ECs from SSc patients and healthy controls were isolated. The effect of iloprost on ECs was examined using immunofluorescence, permeability assays, Matrigel tube formation, and quantitative polymerase chain reaction.ResultsAdherens junctions in SSc were disrupted compared to normal ECs, as indicated by reduced levels of VE‐cadherin and increased permeability in SSc ECs (P < 0.05). Iloprost increased VE‐cadherin clustering at junctions and restored junctional levels of VE‐cadherin in SSc ECs (mean ± SD 37.3 ± 4.3 fluorescence units) compared to normal ECs (mean ± SD 29.7 ± 3.4 fluorescence units; P < 0.05), after 2 hours of iloprost incubation. In addition, iloprost reduced permeability of monolayers, increased tubulogenesis, and blocked EndoMT in both normal and SSc ECs (n ≥ 3; P < 0.05). The effects in normal ECs were inhibited by a function‐blocking antibody that prevents junctional clustering of VE‐cadherin.ConclusionOur data suggest that the long‐lasting effects of iloprost reflect its ability to stabilize adherens junctions, resulting in increased tubulogenesis and barrier function and reduced EndoMT. These findings provide a mechanistic basis for the use of iloprost in treating SSc patients with RP and digital ulcers.
Profiling of Serum Oxylipins During the Earliest Stages of Rheumatoid Arthritis
Authors: Rodríguez‐Carrio Javier , Coras Roxana , Alperi‐López Mercedes , López Patricia , Ulloa Catalina , Ballina‐García Francisco Javier , Armando Aaron M. , Quehenberger Oswald , Guma Mónica , Suárez Ana 
Published: October 2020

ObjectiveEicosanoids modulate inflammation via complex networks involving different pathways and downstream mediators, including oxylipins. Although altered eicosanoids are linked to rheumatoid arthritis (RA), suggesting that metabolization is enhanced, the role of oxylipins in disease stratification remains unexplored. This study was undertaken to characterize oxylipin networks during the earliest stages of RA and evaluate their associations with clinical features and treatment outcomes.MethodsIn total, 60 patients with early RA (according to the American College of Rheumatology/European League Against Rheumatism 2010 criteria), 11 individuals with clinically suspect arthralgia (CSA), and 28 healthy control subjects were recruited. Serum samples were collected at the time of onset. In the early RA group, 50 patients who had not been exposed to disease‐modifying antirheumatic drug (DMARD) or glucocorticoid treatment at the time of recruitment were prospectively followed up at 6 and 12 months after having received conventional synthetic DMARDs. A total of 75 oxylipins, mostly derived from arachidonic, eicosapentanoic, and linoleic acids, were identified in the serum by liquid chromatography tandem mass spectrometry.ResultsUnivariate analyses demonstrated differences in expression patterns of 14 oxylipins across the RA, CSA, and healthy control groups, with each exhibiting a different trajectory. Network analyses revealed a strong grouping pattern of oxylipins in RA patients, whereas in individuals with CSA, a fuzzy network of oxylipins with higher degree and closeness was found. Partial least‐squares discriminant analyses yielded variable important projection scores of >1 for 22 oxylipins, which allowed the identification of 2 clusters. Cluster usage differed among the groups (P = 0.003), and showed associations with disease severity and low rates of remission at 6 and 12 months in RA patients who were initially treatment‐naive. Pathway enrichment analyses revealed different precursors and pathways between the groups, highlighting the relevance of the arachidonic acid pathway in individuals with CSA and the lipooxygenase pathway in patients with early RA. In applying distinct oxylipin signatures, subsets of seropositive and seronegative RA could be identified.ConclusionOxylipin networks differ across stages during the earliest phases of RA. These distinct oxylipin networks could potentially elucidate pathways with clinical relevance for disease progression, clinical heterogeneity, and treatment response.
An iterative method to protect the type I error rate in bioequivalence studies under two‐stage adaptive 2×2 crossover designs
Authors: Molins Eduard , Labes Detlew , Schütz Helmut , Cobo Erik , Ocaña Jordi 
Published: October 2020

AbstractBioequivalence studies are the pivotal clinical trials submitted to regulatory agencies to support the marketing applications of generic drug products. Average bioequivalence (ABE) is used to determine whether the mean values for the pharmacokinetic measures determined after administration of the test and reference products are comparable. Two‐stage 2×2 crossover adaptive designs (TSDs) are becoming increasingly popular because they allow making assumptions on the clinically meaningful treatment effect and a reliable guess for the unknown within‐subject variability. At an interim look, if ABE is not declared with an initial sample size, they allow to increase it depending on the estimated variability and to enroll additional subjects at a second stage, or to stop for futility in case of poor likelihood of bioequivalence. This is crucial because both parameters must clearly be prespecified in protocols, and the strategy agreed with regulatory agencies in advance with emphasis on controlling the overall type I error.We present an iterative method to adjust the significance levels at each stage which preserves the overall type I error for a wide set of scenarios which should include the true unknown variability value. Simulations showed adjusted significance levels higher than 0.0300 in most cases with type I error always below 5%, and with a power of at least 80%. TSDs work particularly well for coefficients of variation below 0.3 which are especially useful due to the balance between the power and the percentage of studies proceeding to stage 2. Our approach might support discussions with regulatory agencies.
Chemoenzymatic Total Syntheses of Artonin I with an Intermolecular Diels–Alderase
Authors: Liu Xiaojing , Yang Jun , Gao Lei , Zhang Liyun , Lei Xiaoguang 
Published: October 2020

AbstractDiels–Alder reaction is one of the most important transformations used in organic synthesis, with the ability to construct two new CC bonds and up to four chiral centers simultaneously. However, the biggest synthetic challenge in Diels–Alder reaction lies in controlling its regio‐, diastereo‐, and enantioselectivity. Using Stille cross‐coupling and enzymatic Diels–Alder reaction as the key steps, the first chemoenzymatic total synthesis of artonin I is achieved in 30% overall yield over only seven steps. This enzymatic Diels–Alder reaction catalyzed by MaDA is featured with excellent endo‐ and enantioselectivity and high catalytic efficiency (kcat/KM = 362 ± 54 mm−1 s−1). These successful chemoenzymatic total syntheses of artonin I and dideoxyartonin I demonstrated the remarkable potential of the intermolecular Diels–Alderase MaDA in biocatalysis.
Mechanisms of epitranscriptomic gene regulation
Authors: Seo Kyung W. , Kleiner Ralph E. 
Published: October 2020

AbstractChemical modifications on RNA can regulate fundamental biological processes. Recent efforts have illuminated the chemical diversity of posttranscriptional (“epitranscriptomic”) modifications on eukaryotic messenger RNA and have begun to elucidate their biological roles. In this review, we discuss our current molecular understanding of epitranscriptomic RNA modifications and their effects on gene expression. In particular, we highlight the role of modifications in mediating RNA‐protein interactions, RNA structure, and RNA‐RNA base pairing, and how these macromolecular interactions control biological processes in the cell.
Actualizing sustainable shrimp cultivation: Innovative knowledge transfer at Dr. Shrimp
Authors: Chen Po‐Chang , Li Li‐Te 
Published: October 2020

AbstractDue to virus infection and unfriendly farming methods, aquatic technology has encountered a series of challenges. Though many efforts have been made, very few studies have focused on the cultivation of shrimp. Therefore, this study aimed to investigate how the founder of Dr. Shrimp transferred innovative and professional knowledge to his trainees, so as to achieve the healthy, non‐toxic, ecofriendly, and sustainable shrimp cultivation that Dr. Shrimp has consistently valued. There are five participants, including the founder, one partner, two clients, and one intern. The data were collected via interview, observation, documents, and analyzed using qualitative content analysis. The results indicated six phases of knowledge and techniques applied at Dr. Shrimp: incentives, communication, acceptance, acquisition, execution, diffusion, which helped to establish the six‐phase model for knowledge transfer and innovation diffusion. It is hoped that the findings can pave the way for other aquatic cultivation to promote sustainable cultivation.
Business strategy and sustainable development: Evidence from China
Authors: Liu Chen , Kong Dongmin 
Published: October 2020

AbstractThis study examines whether and how business strategies affect firms' sustainable development from the view of green innovation. We show that firms following prospector strategy engage in less sustainable development behaviors than those following defender strategies. The negative relation between business strategy and green innovation continues to hold when addressing robustness with alternatives of business strategy and green innovation and addressing potential endogeneity with instrumental variable. We further find that political connection strengthens whereas environmental regulation weakens the negative relation between business strategy and green innovation. Finally, we explore the economic consequences of green innovation caused by strategic differences. Regrettably, the win–win situation of environment and development does not come true.
l‐Lactate Dehydrogenase Identified as a Protein Tyrosine Phosphatase 1B Substrate by Using K‐BIPS
Authors: Acharige Nuwan P. N. , Pflum Mary Kay H. 
Published: October 2020

AbstractKinases and phosphatases are major players in a variety of cellular events, including cell signaling. Aberrant activity or mutations in kinases and phosphatases can lead to diseases such as cancer, diabetes, and Alzheimer's. Compared to kinases, phosphatases are understudied; this is partly a result of the limited methods for identifying substrates. As a solution, we developed a proteomics‐based method called kinase‐catalyzed biotinylation to identify phosphatase substrates (K‐BIPS) that previously identified substrates of Ser/Thr phosphatases using small molecule inhibitors. Here, for the first time, K‐BIPS was applied to identify substrates of a tyrosine phosphatase, protein tyrosine phosphatase 1B (PTP1B), under siRNA knockdown conditions. Eight possible substrates of PTP1B were discovered in HEK293 cells, including the known substrate pyruvate kinase. In addition, l‐lactate dehydrogenase (LDHA) was validated as a novel PTP1B substrate. With the ability to use knockdown conditions with Ser/Thr or Tyr phosphatases, K‐BIPS represents a general discovery tool to explore phosphatases biology by identifying unanticipated substrates.