bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation, Characterization and Reactivity of Key Intermediates Relevant to Reductive (Electro)catalysis with Cp*Rh Complexes Containing Pyridyl‐MIC (MIC=Mesoionic Carbene) Ligands
Authors: Bens Tobias , Walter Robert R. M. , Beerhues Julia , Lücke Clemens , Gabler Julia , Sarkar Biprajit 
Published: September 2023

AbstractIn recent years, metal complexes of pyridyl‐mesoionic carbene (MIC) ligands have been reported as excellent homogeneous and molecular electrocatalysts. In combination with group 9 metals, such ligands form highly active catalysts for hydrogenation/transfer hydrogenation/hydrosilylation catalysis and electrocatalysts for dihydrogen production. Despite such progress, very little is known about the structural/electrochemical/spectroscopic properties of crucial intermediates for such catalytic reactions with these ligands: solvato complexes, reduced complexes and hydridic species. We present here a comprehensive study involving the isolation, crystallographic characterization, electrochemical/spectroelectrochemical/theoretical investigations, and in‐situ reactivity studies of all the aforementioned crucial intermediates involving Cp*Rh and pyridyl‐MIC ligands. A detailed mechanistic study of the precatalytic activation of [RhCp*] complexes with pyridyl‐MIC ligands is presented. Intriguingly, amphiphilicity of the [RhCp*]‐hydride complexes was observed, displaying the substrate dependent transfer of H+, H or H−. To the best of our knowledge, this study is the first of its kind targeting intermediates and reactive species involving metal complexes of pyridyl‐MIC ligands and investigating the interconversion amongst them.
Mechanistic Study on Selenium‐ and Sulfur‐Mediated Isomerization of Hydroxamic Acids
Authors: Meyrelles Ricardo , Schupp Manuel , Maryasin Boris 
Published: September 2023

AbstractAn in‐depth computational study reveals the intriguing mechanism of the recently reported isomerization of hydroxamic acids into para‐aminophenols catalyzed by phenylselenyl bromide under mild conditions. The computations not only align with the reported experimental data, effectively explaining observed phenomena such as para‐selectivity but also shed light on crucial aspects of the reaction mechanism that establish limitations on the scope of the studied rearrangement. Additionally, a joint theoretical/experimental study was performed to examine the potency of the phenylsulfenyl bromide to mediate the reaction under the same conditions.
Gold‐Catalyzed Cyclization of Yndiamides with Isoxazoles via α‐Imino Gold Fischer Carbenes
Authors: Tong Zixuan , Smith Philip J. , Pickford Helena D. , Christensen Kirsten E. , Anderson Edward A. 
Published: September 2023

AbstractGold catalysis is an important method for alkyne functionalization. Here we report the gold‐catalyzed formal [3+2] aminative cyclization of yndiamides and isoxazoles in a direct synthesis of polysubstituted diaminopyrroles, which are important motifs in drug discovery. Key to this process is the formation, and subsequent cyclization, of an α‐imino gold Fischer carbene, which represents a new type of gold carbene intermediate. The reaction proceeds rapidly under mild conditions, with high regioselectivity being achieved by introducing a subtle steric bias between the nitrogen substituents on the yndiamide. DFT calculations revealed that the key to this regioselectivity was the interconversion of isomeric gold keteniminiun ions via a low‐barrier π‐complex transition state, which establishes a Curtin‐Hammett scenario for isoxazole addition. By using benzisoxazoles as substrates, the reaction outcome could be switched to a formal [5+2] cyclization, leading to 1,4‐oxazepines.
Transformation of Highly Hydrophobic Triarylphosphines into Amphiphiles via Staudinger Reaction with Hydrophilic Trichlorophenyl Azide
Authors: Suzuki Hayate , Akiyama Yoshimori , Yamashina Masahiro , Tanaka Yuya , Toyota Shinji 
Published: September 2023

AbstractOwing to its hydrophobic properties and reactivity, triarylphosphines (PAr3) are promising precursors for the development of new amphiphiles. However, an efficient and reliable synthetic method for amphiphiles based on highly hydrophobic PAr3 is still required. Herein, a straightforward transformation of highly hydrophobic PAr3 into amphiphiles via the Staudinger reaction is reported. By simply mixing PAr3 and a hydrophilic trichlorophenyl azide containing two hydrophilic chains, amphiphiles bearing a N=P bond (i. e., an azaylide moiety) were quantitatively formed. The obtained azaylide‐based amphiphiles were remarkably water‐soluble, enabling their spontaneous self‐assembly into 2 nm‐sized micelles composed of 4–5 molecules in water with a low critical micelle concentration (up to 0.05 mM or less) due to the effective intermolecular interactions among the hydrophobic surfaces. Although the azaylide moiety is easily hydrolyzed in the presence of water, the azaylide in the amphiphiles displayed notable stability in water even at 60 h, which stems from the LUMO modulation induced by the presence of three electron‐withdrawing chloro groups and two twisted alkoxycarbonyl groups, according to DFT calculations. An amphiphile having a large hydrophobic surface solubilized various hydrophobic organic dyes through efficient intermolecular interactions, resulting in the dyes exhibiting either monomer or excimer emissions in water.
Spectrum of random d‐regular graphs up to the edge
Authors: Huang Jiaoyang , Yau Horng‐Tzer 
Published: September 2023

AbstractConsider the normalized adjacency matrices of random d‐regular graphs on N vertices with fixed degree . We prove that, with probability for any , the following two properties hold as provided that : (i) The eigenvalues are close to the classical eigenvalue locations given by the Kesten–McKay distribution. In particular, the extremal eigenvalues are concentrated with polynomial error bound in N, that is, . (ii) All eigenvectors of random d‐regular graphs are completely delocalized.
Equivalent circuit modeling and optimization design for a novel double‐stator linear‐rotary switched reluctance motor
Authors: Qi Ge , Bu Zhenfan , Xu Shuai , Jiang Xiaochang 
Published: September 2023

SummaryThe energy coupling behavior is propagated through the magnetic field and would seriously affect the operation performance of two‐degree‐of‐freedom motion system based on linear‐rotary motor. This paper proposes a novel double‐stator linear‐rotary switched reluctance motor (DSLR‐SRM) to suppress the energy coupling behavior. First, the structure and operation principles of DSLR‐SRM are presented. The two stators of DSLR‐SRM are radially arranged to perform the independent magnetic circuit and suppress the energy coupling behavior through the magnetic field. Then, an equivalent circuit model is established to shorten the modeling and calculation time. It could be found that the energy coupling behavior directly affects the torque and force performance. Next, the sensitivity of the DSLR‐SRM dimensions is developed. Meanwhile, the dimensions of DSLR‐SRM are optimized to enhance the torque and force output via TOPSIS decision‐making. Finally, the validity of equivalent circuit modeling analysis and optimization results are verified through three‐dimensional finite element model.
Fractional delay Newton structure for Lagrangian interpolation in PV integrated grid connected system
Authors: Arora Ankita , Singh Alka 
Published: September 2023

SummaryThis paper proposes a fractional delay (FD) Newton structure for Lagrangian interpolation in single phase grid integrated photovoltaic (PV) system. The structure has been designed for achieving shunt compensation and as a phase locked loop circuit for synchronization. The designed controller performs multiple tasks of feeding the active power to meet the load demand and simultaneously providing reactive power compensation, power factor improvement, and compensating other power quality voltage and load current harmonics. Further, synchronization poses a severe challenge in integrating the PV power electronic converters to the grid. The FD filter is used to discretize the continuous time signal at any time instant using interpolation algorithm employing the non‐integral value of the sampling rate delays. The FD delay filter is made adaptive and self‐learning by using least mean square algorithm. The designed synchronization technique meets the objective of faithfully tracking the phase of the grid voltage under all grid disturbances such as under voltage, overvoltage, frequency variations, and phase angle disturbances in a precise manner.
Early‐onset Alzheimer's disease explained by polygenic risk of late‐onset disease?
Authors: Mantyh William G. , Cochran J. Nicholas , Taylor Jared W. , Broce Iris J. , Geier Ethan G. , Bonham Luke W. , Anderson Ashlyn G. , Sirkis Daniel W. , Joie Renaud La , Iaccarino Leonardo , Chaudhary Kiran , Edwards Lauren , Strom Amelia , Grant Harli , Allen Isabel E. , Miller Zachary A. , Gorno‐Tempini Marilu L. , Kramer Joel H. , Miller Bruce L. , Desikan Rahul S. , Rabinovici Gil D. , Yokoyama Jennifer S. 
Published: September 2023

AbstractEarly‐onset Alzheimer's disease (AD) is highly heritable, yet only 10% of cases are associated with known pathogenic mutations. For early‐onset AD patients without an identified autosomal dominant cause, we hypothesized that their early‐onset disease reflects further enrichment of the common risk‐conferring single nucleotide polymorphisms associated with late‐onset AD.We applied a previously validated polygenic hazard score for late‐onset AD to 193 consecutive patients diagnosed at our tertiary dementia referral center with symptomatic early‐onset AD. For comparison, we included 179 participants with late‐onset AD and 70 healthy controls. Polygenic hazard scores were similar in early‐ versus late‐onset AD. The polygenic hazard score was not associated with age‐of‐onset or disease biomarkers within early‐onset AD. Early‐onset AD does not represent an extreme enrichment of the common single nucleotide polymorphisms associated with late‐onset AD. Further exploration of novel genetic risk factors of this highly heritable disease is warranted.Highlights
There is a unique genetic architecture of early‐ versus late‐onset Alzheimer's disease (AD).
Late‐onset AD polygenic risk is not an explanation for early‐onset AD.
Polygenic risk of late‐onset AD does not predict early‐onset AD biology.
Unique genetic architecture of early‐ versus late‐onset AD parallels AD heterogeneity.
Fluoxetine enhances the antitumor effect of olfactory ensheathing cell‐thymidine kinase/ganciclovir gene therapy in human glioblastoma multiforme cells through upregulation of Connexin43 levels
Authors: Hosseindoost Saereh , Dehpour Ahmad R. , Dehghan Samaneh , Javadi Seyed A. H. , Arjmand Babak , Fallah Ali , Hadjighassem Mahmoudreza 
Published: September 2023

AbstractGlioblastoma multiforme (GBM) is the most invasive form of primary brain astrocytoma, resulting in poor clinical outcomes. Herpes simplex virus thymidine kinase/ganciclovir (HSV‐TK/GCV) gene therapy is considered a promising strategy for GBM treatment. Since Connexin43 (Cx43) expression is reduced in GBM cells, increasing Cx43 levels could enhance the effectiveness of gene therapy. The present study aims to examine the impact of fluoxetine on HSV‐TK/GCV gene therapy in human GBM cells using human olfactory ensheathing cells (OECs) as vectors. The effect of fluoxetine on Cx43 levels was assessed using the western blot technique. GBM‐derived astrocytes and OECs‐TK were Cocultured, and the effect of fluoxetine on the Antitumor effect of OEC‐TK/GCV gene therapy was evaluated using MTT assay and flow cytometry. Our results showed that fluoxetine increased Cx43 levels in OECs and GBM cells and augmented the killing effect of OECs‐TK on GBM cells. Western blot data revealed that fluoxetine enhanced the Bax/Bcl2 ratio and the levels of cleaved caspase‐3 in the coculture of OECs‐TK and GBM cells. Moreover, flow cytometry data indicated that fluoxetine increased the percentage of apoptotic cells in the coculture system. This study suggests that fluoxetine, by upregulating Cx43 levels, could strengthen the Antitumor effect of OEC‐TK/GCV gene therapy on GBM cells.
Embryonic development in the bonnethead (Sphyrna tiburo), a viviparous hammerhead shark
Authors: Byrum Steven R. , Frazier Bryan S. , Grubbs R. Dean , Naylor Gavin J. P. , Fraser Gareth J. 
Published: September 2023

AbstractBackgroundThe hammerhead sharks (family Sphyrnidae) are an immediately recognizable group of sharks due to their unique head shape. Though there has long been an interest in hammerhead development, there are currently no explicit staging tables published for any members of the group. The bonnethead Sphyrna tiburo is the smallest member of Sphyrnidae and is abundant in estuarine and nearshore waters in the Gulf of Mexico and Western North Atlantic Ocean. Due to their relative abundance, close proximity to shore, and brief gestation period, it has been possible to collect and document multiple embryonic specimens at progressive stages of development.ResultsWe present the first comprehensive embryonic staging series for the Bonnethead, a viviparous hammerhead shark. Our stage series covers a period of development from stages that match the vertebrate phylotypic period, from Stage 23, through stages of morphological divergence to complete development at birth—Stage 35). Notably, we use a variety of techniques to document crucial stages that lead to their extreme craniofacial diversity, resulting in the formation of one of the most distinctive characters of any shark species, the cephalofoil or hammer‐like head.ConclusionDocumenting the development of hard‐to‐access vertebrates, like this viviparous shark species, offers important information about how new and diverse morphologies arise that otherwise may remain poorly studied. This work will serve as a platform for future comparative developmental research both within sharks and across the phylogeny of vertebrates, underpinning the extreme potential of craniofacial development and morphological diversity in vertebrate animals.
Sperm‐dependent asexual species and their role in ecology and evolution
Authors: Janko Karel , Mikulíček Peter , Hobza Roman , Schlupp Ingo 
Published: September 2023

AbstractSexual reproduction is the primary mode of reproduction in eukaryotes, but some organisms have evolved deviations from classical sex and switched to asexuality. These asexual lineages have sometimes been viewed as evolutionary dead ends, but recent research has revealed their importance in many areas of general biology. Our review explores the understudied, yet important mechanisms by which sperm‐dependent asexuals that produce non‐recombined gametes but rely on their fertilization, can have a significant impact on the evolution of coexisting sexual species and ecosystems. These impacts are concentrated around three major fields. Firstly, sperm‐dependent asexuals can potentially impact the gene pool of coexisting sexual species by either restricting their population sizes or by providing bridges for interspecific gene flow whose type and consequences substantially differ from gene flow mechanisms expected under sexual reproduction. Secondly, they may impact on sexuals' diversification rates either directly, by serving as stepping‐stones in speciation, or indirectly, by promoting the formation of pre‐ and postzygotic reproduction barriers among nascent species. Thirdly, they can potentially impact on spatial distribution of species, via direct or indirect (apparent) types of competition and Allee effects. For each such mechanism, we provide empirical examples of how natural sperm‐dependent asexuals impact the evolution of their sexual counterparts. In particular, we highlight that these broad effects may last beyond the tenure of the individual asexual lineages causing them, which challenges the traditional perception that asexual lineages are short‐lived evolutionary dead ends and minor sideshows. Our review also proposes new research directions to incorporate the aforementioned impacts of sperm‐dependent asexuals. These research directions will ultimately enhance our understanding of the evolution of genomes and biological interactions in general.
Variation in bill surface area is associated with local climatic factors across populations of the plain laughingthrush
Authors: Liu Pengfei , Lou Yingqiang , Yao Jingxiao , Wang Linghui , Møller Anders Pape , Sun Yuehua 
Published: September 2023

AbstractRecent studies have found that avian bill and tarsus morphology may have evolved in response to climatic conditions, and these organs play important roles in thermoregulation and water retention in extreme environments. Here, we examined whether bill surface area and tarsus length were associated with climatic conditions in the plain laughingthrush, Garrulax davidi, which mainly occurs in north China and occupies several climatic zones from east to west. We measured bill surface area and tarsus length in 321 adults from 11 populations, almost encompassing all habitat types of the species. We analyzed the relationships among these morphological traits and local climatic factors. Bill surface area was positively correlated with maximum temperature, indicating that bill surface area tended to be larger in hotter environments. Furthermore, we found a negative relationship among bill surface area and winter precipitation, indicating that bill surface area tended to be larger in arid areas. However, we did not find any relationships between tarsus length and climatic factors. These results suggest that local climates may shape the evolution of bill morphology divergence, and summer seems to be the critical season for thermoregulation in this temperate zone passerine.
Effects of geo‐climate factors on phenotypic variation in cone and seed traits of Pinus yunnanensis
Authors: Gao Chengjie , Liu Fangyan , Miao Yingchun , Li Jin , Liu Zirui , Cui Kai 
Published: September 2023

AbstractEvaluating variations in reproductive traits and the response of the variations to geo‐climate conditions are essential for understanding the persistence, evolution, and range dynamics of plant populations. However, there are insufficient studies to attempt to analyze the importance of geo‐climate factors in explaining within‐ or among‐population variation in reproductive traits. We examined 14 traits for 2671 cones of Pinus yunnanensis collected from nine populations in the mountains of Southwest China to characterize the patterns of phenotypic variation of traits and estimate environmental effects on these trait performances and trait variation. We found the contribution of intrapopulation variation to the overall variation was greater than the interpopulation variation and the larger coefficients of variation for the populations lying at the edge of northern and southern regions. Climatic variables are more important than geographical and tree size variables in their relationships to cone and seed traits. Populations in more humid and warmer climate expressed greater cone and seed weight and seed number but lower seed abortion rate, while the larger coefficients of variation in seed weight and number were detected in northern and southern marginal regions with drier or colder climate. Our study illustrates that intraspecific trait variation should be considered when examining plant species response to changing climate and suggests that the high variability rather than high quality of seed traits in the marginal regions with drier or colder climate might foster plant‐population persistence in stressful conditions.
Psychometric evaluation of the Pain Vigilance and Awareness Questionnaire (PVAQ) in fibromyalgia: Confirmatory factor analysis and the development of a Swedish 8‐item version
Authors: Hoffmann Alice Ahnlund , Frostell Elsa , Hedman‐Lagerlöf Maria , McCracken Lance M. , Axelsson Erland 
Published: September 2023

AbstractBackgroundExcessive attention to pain, or hypervigilance, is associated with negative outcomes in chronic pain conditions such as fibromyalgia. The Pain Vigilance and Awareness Questionnaire (PVAQ) is a self‐report questionnaire to measure attention to pain. This study aimed to evaluate the psychometric properties of a Swedish version of the PVAQ.MethodsPsychometric evaluation on cross‐sectional data derived from a clinical trial for fibromyalgia (N = 274). We evaluated item characteristics, factor structure in a confirmatory factor analytic framework, internal consistency, and construct validity in terms of correlations with other clinical variables.ResultsThough confirmatory factor analysis did not result in a satisfactory solution for the full 16‐item scale, acceptable two‐factor solutions could be based on either nine or eight items (the PVAQ‐9 and PVAQ‐8). Internal consistency for both the PVAQ‐9 and PVAQ‐8 were good to excellent, and associations with pain catastrophizing, anxiety, depression, disability, and overall fibromyalgia impact were largely supportive of construct validity. An unexpected result was that, contrary to previous findings, no version of the PVAQ correlated consistently with pain intensity.ConclusionsThe Swedish PVAQ‐9 and PVAQ‐8 appear to have acceptable psychometric properties when administered online to individuals with fibromyalgia. The PVAQ‐8 may be preferable due to being shorter and including an equal number of items per factor. Replication is warranted.SignificanceThis study evaluated the psychometric properties of a Swedish translation of the PVAQ in individuals with fibromyalgia. No convincing factor structure was found for the 16‐item version. We could, however, confirm the factor structure of an established 9‐item version (the PVAQ‐9), and recommend further use of a new 8‐item version (the PVAQ‐8). In summary, the PVAQ exhibited more convincing psychometric properties when the number of items was roughly cut in half.
The identity‐attitude nexus in the representation of energy transition in a coal region (Sulcis, Italy): An exploration through the Structural Topic Model
Authors: Rizzoli Valentina , Biddau Fulvio , Sarrica Mauro 
Published: September 2023

AbstractThis article explores the contribution of the Structural Topic Model (STM) to study the intertwining of social representations, attitudes, and identities. We examine newspapers’ discourse on energy transition in a coal‐dependent region (Sulcis, Italy), whose identity and economy are built around mining and carbon‐intensive industry. Drawing upon Social Representations Theory, we combined STM and qualitative content analysis to examine how newspapers represented the energy issue in Sulcis, and how these representations (including denotative and connotative facets) differed according to the social identities’ salience. Results show that coal is legitimated by discourses making salient local identities and providing continuity in the place–identity link, with no alternative to extractivism. When the Sardinian superordinate identity becomes salient, new themes emerge (e.g., renewables) but energy transition retains ambivalent or negative connotations. Overall representations seem to replicate and reflect processes of domination and injustice hindering a just transition, potentially explaining negative attitudes and collective resistance to decarbonization.