bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steric Activation in the Nazarov Cyclization of Fully Substituted Divinyl Ketones
Authors: Chen Shuqi , Keto Angus B. , El‐Hawli Ahmad , Gahan Lawrence R. , White Jonathan M. , Krenske Elizabeth H. , Flynn Bernard L. 
Published: October 2024

AbstractFully substituted divinyl ketones (fsDVKs) have long been regarded as resistant to Nazarov cyclization (NC) unless they contain strategically positioned electronically activating substituents. Here, however, we show that fsDVKs bearing only electronically neutral alkyl or aryl groups actually undergo facile NC due to steric crowding in the pentadienyl cation intermediate, which raises its energy and reduces the barrier height to cyclization. Strongly ionizing and suitably bulky acid moieties further increase the energy of this intermediate cation, favoring cyclization. These features enable NCs of fsDVKs to be employed in the ready construction of multiple contiguous all‐carbon quaternary stereocenters under mild conditions, in the absence of electronically activating groups.
Enantioselective Organozinc Addition to Aldehydes Using Planar Chiral [2.2]Paracyclophane‐Imidazoline N,O‐Ligands
Authors: Vivek Kumar Sundaravel , Guiry Patrick J 
Published: October 2024

AbstractWe present an improved and convenient synthesis of [2.2]paracyclophane‐imidazoline N,O‐ligands with central and planar chirality in seven steps starting from [2.2]paracyclophane. The utility of these ligands in organozinc additions to aldehydes is described. The asymmetric ethylation of aldehydes proceeded with enantioselectivities of up to 97 % ee, while the asymmetric arylation of aldehydes gave up to 95 % ee (R) and 82 % ee (S) using (S,S,SP)‐UCD‐Imphanol and (S,S,RP)‐UCD‐Imphanol, respectively.
Rectifiability, finite Hausdorff measure, and compactness for non‐minimizing Bernoulli free boundaries
Authors: Kriventsov Dennis , Weiss Georg S. 
Published: October 2024

AbstractWhile there are numerous results on minimizers or stable solutions of the Bernoulli problem proving regularity of the free boundary and analyzing singularities, much less is known about critical points of the corresponding energy. Saddle points of the energy (or of closely related energies) and solutions of the corresponding time‐dependent problem occur naturally in applied problems such as water waves and combustion theory. For such critical points —which can be obtained as limits of classical solutions or limits of a singular perturbation problem—it has been open since (Weiss, 2003) whether the singular set can be large and what equation the measure satisfies, except for the case of two dimensions. In the present result we use recent techniques such as a frequency formula for the Bernoulli problem as well as the celebrated Naber–Valtorta procedure to answer this more than 20 year old question in an affirmative way: For a closed class we call variational solutions of the Bernoulli problem, we show that the topological free boundary (including degenerate singular points , at which as ) is countably ‐rectifiable and has locally finite ‐measure, and we identify the measure completely. This gives a more precise characterization of the free boundary of in arbitrary dimension than was previously available even in dimension two. We also show that limits of (not necessarily minimizing) classical solutions as well as limits of critical points of a singularly perturbed energy are variational solutions, so that the result above applies directly to all of them.
Mechanically Interlocked Macrocycles on Covalent Networks for Energy and Environmental Applications
Authors: Gu Muhua , Suleman Suleman , Kim Yoonseob 
Published: October 2024

AbstractMacrocycles’ unique properties of interacting with guest molecules have been an intriguing scientific endeavor for many decades. They are potentially practically useful for engineering applications, especially in energy and environmental applications. These applications are usually demanding, involving a high temperature, pH, voltage, etc., thus, finding suitable substrates that can endure working environments and sustain macrocycles’ properties is highly desirable. In that sense, covalent networks are ideal as they are chemically/electrochemically/thermally stable and can be porous by design. Emerging porous materials, especially covalent organic frameworks (COFs), could be suitable as their porous spaces allow macrocycles to interact with guest species. In the past seven years, we have seen the rise of mechanically interlocked macrocycles on covalent networks (MIMc‐CNs) that translate macrocycles’ properties into macroscale materials. In this conceptual review, we first describe the idea of integrating MIMcs into COFs or conventional amorphous polymers. Next, we review the reported representative MIMc‐CNs used in energy and environmental applications. We also provide a brief outlook for the future directions for the MIMc‐CNs research.
A Hybrid 2D‐to‐3D in vitro Differentiation Platform Improves Outcomes of Cerebral Cortical Organoid Generation in hiPSCs
Authors: Whye Dosh , Norabuena Erika M. , Srinivasan Gayathri Rajaram , Wood Delaney , Polanco Taryn J. , Makhortova Nina R. , Sahin Mustafa , Buttermore Elizabeth D. 
Published: October 2024

AbstractThree‐dimensional (3D) cerebral cortical organoids are popular in vitro cellular model systems widely used to study human brain development and disease, compared to traditional stem cell–derived methods that use two‐dimensional (2D) monolayer cultures. Despite the advancements made in protocol development for cerebral cortical organoid derivation over the past decade, limitations due to biological, mechanistic, and technical variables remain in generating these complex 3D cellular systems. Building from our previously established differentiation system, we have made modifications to our existing 3D cerebral cortical organoid protocol that resolve several of these technical and biological challenges when working with diverse groups of human induced pluripotent stem cell (hiPSC) lines. This improved protocol blends a 2D monolayer culture format for the specification of neural stem cells and expansion of neuroepithelial progenitor cells with a 3D system for improved self‐aggregation and subsequent organoid development. Furthermore, this “hybrid” approach is amenable to both an accelerated cerebral cortical organoid protocol as well as an alternative long‐term differentiation protocol. In addition to establishing a hybrid technical format, this protocol also offers phenotypic and morphological characterization of stage‐specific cellular profiles using antibodies and fluorescent‐based dyes for live cell imaging. © 2024 Wiley Periodicals LLC.Basic Protocol 1: hiPSC‐based 2D monolayer specification into neural stem cells (NSCs)Basic Protocol 2: Serial passaging and 2D monolayer expansion of neuroepithelial progenitor cells (NPCs)Support Protocol 1: Direct cryopreservation and rapid thawing of NSCs and NPCsBasic Protocol 3: Bulk aggregation of 3D neurospheres and accelerated cerebral cortical organoid differentiationAlternate Protocol 1: Bulk aggregation of 3D neurospheres and long‐term cerebral cortical organoid differentiationSupport Protocol 2: High‐throughput 3D neurosphere formation and 2D neurosphere migration assaySupport Protocol 3: LIVE/DEAD stain cell imaging assay of 3D neurospheresSupport Protocol 4: NeuroFluor NeuO live cell dye for 3D cerebral cortical organoids
Efficient Selective CO2 Composite Sorbent from Amino Acid Ionic Liquids and Silica Gel: 2H NMR Spectroscopy Provides Insight on the CO2‐Binding Mechanism and in‐Pore Microscopic Viscosity
Authors: Sheshkovas Andrey Z. , Khudozhitkov Alexander E. , Veselovskaya Janna V. , Kolokolov Daniil I. , Stepanov Alexander G. , Ludwig Ralf 
Published: October 2024

AbstractA promising CO2 sorbent based on the [Emim][Gly] (1‐ethyl‐3‐methylimidazolium glycinate)/silica gel composite has been studied. CO2 sorption experiments have shown that the optimum loading of [Emim][Gly] ionic liquid in silica gel is 40 wt.%. The 2‐step process CO2 binding mechanism in [Emim][Gly] has been proposed based on the results of sorption experiments, 2H NMR spectroscopy and ab‐initio calculations. The impact of CO2 on the microscopic viscosity and the dynamical melting of ionic liquid has been thoroughly investigated. 2H NMR spectroscopy has revealed that CO2 strongly binds cation and anion in [Emim][Gly], forcing them to move in a correlated fashion.
High‐Entropy Selenides with Tunable Lattice Distortion as Efficient Electrocatalysts for Oxygen Evolution Reaction
Authors: Li Laiquan , Li Changfa , Du Jiale , Huang Qianwei , Duan Jingjing , Liu Jiawei , Chen Sheng 
Published: October 2024

AbstractDeveloping stable and active electrocatalysts is crucial for enhancing the oxygen evolution reaction (OER) efficiency, which sluggish kinetics hinder sustainable hydrogen production. High entropy selenides (HESes) feature with random distribution of multiple metals cations and unique electronic and size effect of Se anion, allowing for precious regulation of their catalytic properties towards high OER activity. In this work, we report a series of high‐entropy selenides catalysts with tunable lattice strain for electrocatalytic oxygen evolution. Electrochemical measurements show that the quinary (NiCoMnMoFe)Sex requires only 291 mV to reach 10 mA cm−2 and exhibits a superior stability with negligible current decay during 100 h′s continuous operation. By combining experimental measurements and theoretical calculation, the study reveals that the lattice distortion, reflected by the local microstrain near the active site, plays a vital role in boosting the OER activity of HESes.
Analysis and Design of a Battery and Supercapacitor‐Based Propulsion System for Electric Vehicles
Authors: Singh Minakshi , Kumar Singh Ankit , Prakash Mittal Alok , Kumar Mishra Anjanee 
Published: October 2024

ABSTRACTThis work deals with the design and development of a dual source based propulsion architecture for electric vehicles. The converter utilized for the propulsion system is derived from a conventional CuK converter, which operates in a bidirectional power flow mode. The proposed propulsion system has two energy sources: a battery and a supercapacitor (SC). The proposed system has continuous input and output currents at low and high voltage sides, which improves the cycle life of hybrid energy storage (SC and battery) and the DC‐link capacitor. Further, the proposed converter has magnetic reduction compared to a conventional two‐input bidirectional CuK converter. Moreover, an effective and simpler control strategy (only one switch is pulse width modulated (PWM) operated at a time) has been developed for energy management between sources during charging (regenerative braking) and discharging (propulsion), which is effectively verified by simulation and experimental results. Further, a frequency domain (bode plot)‐based technique is used for controller design and stability analysis of the proposed system.
An Ultra‐High Voltage AC/DC Isolated Matrix Converter Applied to V2G Electric Vehicle Charging Piles
Authors: Liu Liang , Tang Jianlin , Yang Siqi , Qian Bin , Wu Qiong , Zhou Mi , Jun Pingxinjue , Zhang Fan 
Published: October 2024

ABSTRACTIn recent years, in order to alleviate global environmental problems, renewable energy power generation and the electric vehicle industry have been vigorously promoted by many countries. During this background, many scholars have proposed the development of vehicle‐to‐grid (V2G) systems to alleviate the impact of renewable energy generation on grid quality, and electric vehicle charging piles are the core part of realizing V2G systems. This article proposes an ultra‐high voltage AC/DC isolated matrix converter applied to V2G electric vehicle charging piles, which can achieve bidirectional flow of energy, and proposes the control strategy that can reduce the current stress of the device. In addition, the ultra‐high voltage module of the proposed topology can provide wide voltage range and high voltage charging power for different types of electric vehicles. The proposed topology and control strategy are verified by simulation.
Wild Bee Conservation in Viticulture: Effects of Semi‐Natural Habitats, Organic Management, and Fungicide Reduction
Authors: Kaczmarek Marvin , Entling Martin H. , Hoffmann Christoph 
Published: October 2024

ABSTRACTIn agricultural landscapes, the removal of semi‐natural habitats (SNH) and the intensive use of pesticides contribute to declines of biodiversity, including crop pollinators such as bees (Hymenoptera: Apoidea). However, effects of pesticide use and landscape characteristics on bees have rarely been studied together. In this study, we investigated how SNH in the surrounding landscape, organic and conventional management, and the reduction of fungicides affect wild bee diversity in 32 vineyards in southwest Germany. We used yellow pan traps to sample bees in a crossed design of management (organic vs. conventional) and fungicide use (reduced in fungus‐resistant grape varieties vs. regular) along a gradient with increasing proportions of SNH in the surrounding landscape. Higher proportions of SNH influenced species composition of bees and increased the abundance and richness of above‐ground‐nesting species. Organic vineyards had a 49% higher abundance of bees compared to conventional vineyards. The reduction of fungicides did not affect bee diversity nor abundance. The absence of a response to fungicide intensity suggests that the benefit of organically managed vineyards to wild bees was through differences in their vegetation management, which is in line with the positive response of bees to SNH in the surrounding landscape. Synthesis and applications: Our study underlines that the local provision of diverse vegetation in vineyards and the landscape‐scale provision of suitable SNH are key factors for wild bee conservation in viticulture.
Predicting the Potential Distribution of Rare and Endangered Emmenopterys henryi in China Under Climate Change
Authors: Cai Hanwei , Zhang Guangfu 
Published: October 2024

ABSTRACTClimate change has a pivotal impact on the potential distribution of endangered and relic tree species. Probably due to unrepresentative sampling and single algorithm, at present, there are different views on the potential range of the endangered tree Emmenopterys henryi, endemic to China. Here, we first collated 612 occurrence records and 22 environmental variables including climate, topography, and soil. Combined the Biomod2 with MaxEnt, we then predicted its past, current, and future potential suitable area in China, and determined the key factors influencing its distribution. The ensemble model results showed that the main environmental variables affecting this species were the minimum temperature of the coldest month (BIO6), precipitation of warmest quarter (BIO18), and temperature seasonality (BIO4). Its current potential distribution area was 176.53 × 104 km2, mainly concentrated in eastern, central, and southwestern China. Collectively, the suitable area of E. henryi would averagely decrease by 3.90% in all 16 future scenarios, with its centroid largely migrating northeastward. Our findings indicate that the endangered E. henryi covered 18 provinces in China, having a larger area than known. Moreover, climate change may have an adverse effect on its potential distribution. In addition, the ensemble model can produce more effective prediction outcomes than MaxEnt for such endemic tree species with large environmental range. We recommend increasing sample representativeness by analyzing the completeness properties of sample coverage, and simultaneously selecting appropriate algorithms to ensure the reliability of distribution prediction for endangered and relict tree species.
Understanding the chemodiversity of plants: Quantification, variation and ecological function
Authors: Petrén Hampus , Anaia Redouan Adam , Aragam Kruthika Sen , Bräutigam Andrea , Eckert Silvia , Heinen Robin , Jakobs Ruth , Ojeda‐Prieto Lina , Popp Moritz , Sasidharan Rohit , Schnitzler Jörg‐Peter , Steppuhn Anke , Thon Frans M. , Unsicker Sybille B. , van Dam Nicole M. , Weisser Wolfgang W. , Wittmann Meike J. , Yepes Sol , Ziaja Dominik , Müller Caroline , Junker Robert R. 
Published: October 2024

AbstractPlants produce a great number of phytochemicals serving a variety of different functions. Recently, the chemodiversity of these compounds (i.e., the diversity of compounds produced by a plant) has been suggested to be an important aspect of the plant phenotype that may shape interactions between plants, their environment, and other organisms. However, we lack an agreement on how to quantify chemodiversity, which complicates conclusions about the functional importance of it. Here, we discuss how chemodiversity (deconstructed into components of richness, evenness and disparity) may relate to different ecologically relevant aspects of the phenotype. Then, we systematically review the literature on chemodiversity to examine methodological practices, explore patterns of variability in diversity across different levels of biological organization, and investigate the functional role of this diversity in interactions between plants and other organisms. Overall, the reviewed literature suggests that high chemodiversity is often beneficial for plants, although a heterogeneity of methodological approaches partly limits what general conclusions can be drawn. Importantly, to support future research on this topic, we provide a framework with a decision tree facilitating choices on which measures of chemodiversity are best used in different contexts and outline key questions and avenues for future research. A more thorough understanding of chemodiversity will provide insights into its evolution and functional role in ecological interactions between plants and their environment.
Narwhal (Monodon monoceros) associations with Greenland summer meltwater release
Authors: Laidre Kristin L. , Zahn Marie J. , Simon Malene , Ladegaard Michael , Stafford Kathleen M. , Phillips Elizabeth , Moon Twila , Stern Harry L. , Cohen Benjamin 
Published: October 2024

AbstractClimate change is rapidly transforming the coastal margins of Greenland. At the same time, there is increasing recognition that marine‐terminating glaciers provide unique and critical habitats to ice‐associated top predators. We investigated the connection between a top predator occupying glacial fjord systems in Northwest Greenland and the properties of Atlantic‐origin water and marine‐terminating glaciers through a multiyear interdisciplinary project. Using passive acoustic monitoring, we quantified the summer presence and autumn departure of narwhals (Monodon monoceros) at glacier fronts in Melville Bay and modeled what glacier fjord physical attributes are associated with narwhal occurrence. We found that narwhals are present at glacier fronts after Greenland Ice Sheet peak summer runoff and they remain there during the period when the water column is becoming colder and fresher. Narwhals occupied glacier fronts when ocean temperatures ranged from −0.6 to 0.8°C and salinities between 33.2 and 34.0 psu at around 200 m depth and they departed on their southbound migration between October and November. Narwhals' departure was approximately 4 weeks later in 2019 than in 2018, after an extreme 2019 summer heatwave event that also delayed sea ice formation by 2 months. Our study provides further support for the niche conservative narwhal's preference for cold ocean temperatures. These results may inform projections about how future changes will impact narwhal subpopulations, especially those occupying Greenland glacial fjords.
Validation of an eDNA‐based workflow for monitoring inter‐ and intra‐specific CytB haplotype diversity of alpine amphibians
Authors: Zanovello Lucia , Martins Filipa M. S. , Girardi Matteo , Casari Stefano , Galla Giulio , Beja Pedro , Pedrini Paolo , Bertorelle Giorgio , Hauffe Heidi C. 
Published: October 2024

AbstractEnvironmental DNA (eDNA) analysis is a promising tool for monitoring wild animal populations and, more recently, their genetic variability. In this study, we used the mitochondrial Cytochrome B gene to develop and apply new eDNA metabarcoding assays targeting amphibian families and genera in order to estimate both inter‐ and intraspecific genetic diversity. We designed and tested seven new primer pairs (a) in silico against an amphibian reference database based on the target genera; (b) in vitro on tissue samples of the target species; and (c) in situ on water samples from 38 wetlands in the Province of Trento (Italy). Overall, most target species were amplified successfully, although some markers also amplified non‐target amphibian species. In addition, to complete the workflow, we compared the performance of three different bioinformatic pipelines (namely, MICCA with VSEARCH, and OBITools using ecotag or metabinkit), in retrieving reads and exact sequence variants from the metabarcoding datasets. Overall, the MICCA based pipeline retrieved more reads, but less putative haplotypes of amphibians. After comparing these sequences with previously known haplotypes from tissue‐based studies, when the aim is to both decrease the probability of detecting false haplotypes and retrieve the highest number of reads, we suggest using MICCA+VSEARCH, unless a direct comparison with tissue‐based genetic data is possible.
Co‐encapsulation of ω‐3 LC‐PUFAs and carotenoids for enhanced synergistic antioxidant effects
Authors: Zhu Yongchao , Zhang Chuang , Sun Xinyi , Wen Jingyuan , Quek Siew Young 
Published: October 2024

AbstractThis work aimed to study the co‐encapsulation of ω‐3 Long‐Chain Polyunsaturated Fatty Acids (LC‐PUFAs) with β‐carotene, lutein and zeaxanthin and the cellular uptake of carotenoids. Monodisperse microcapsules with good properties, including particle surface morphology, water activity, microencapsulation efficiency, and glass transition temperature, were successfully prepared using a microfluidic‐jet spray drier with OSA‐modified starch as a wall matrix. The presence of carotenoids enhanced the oxidative stability of ω‐3 LC‐PUFAs. Caco‐2 cell uptakes of the carotenoids from the spray‐dried microcapsules were studied and compared to those encapsulated in the methylcellulose (MC) or xanthan gum (XG) delivery systems. The microcapsules encapsulated by OSA‐modified starch showed higher cellular uptakes of carotenoids (i.e., β‐carotene, 0.31 μg/mg protein; lutein, 0.52 μg/mg protein; zeaxanthin, 0.54 μg/mg protein) than those in the MC or XG delivery systems. The Caco‐2 cell uptake depended on carotenoid type, where hydrocarbon carotenoids (i.e., β‐carotene) had lower uptake than oxygenated carotenoids (i.e., lutein or zeaxanthin).
Divalent Lanthanide Hydride Complexes
Authors: Stapf Emma , Hinz Alexander 
Published: October 2024

AbstractMolecular hydride complexes have attracted recent attention, and divalent lanthanides as central atoms in particular are very interesting. They open up possibilities of combining hydride reactivity and lanthanide reactivity. To date, only Yb(II), Eu(II) and Sm(II) as well as a mixed‐valent Dy(II)/Dy(III) hydride complexes have been isolated and characterised but the known examples are still low in numbers. In this contribution the development of divalent lanthanide chemistry is summarised, and structural features, reactivity patterns in stoichiometric and catalytic reactions as well as spectroscopic details are outlined.
Additive‐Free and Diastereoselective Synthesis for Trans‐Disubstituted‐2,3‐Dihydro‐Benzofurans via [4+1] Annulation between p‐QMs and TFISYs
Authors: Li Yi‐Hui , Wang Chuan‐Chuan , Ren Meng‐Ru , Wang Qing‐Long , Chen Ya‐Jing 
Published: October 2024

AbstractAn additive‐free and diastereoselective [4+1] annulation between ortho‐hydroxyphenyl‐substituted para‐quinone methides and CF3‐substituted imidoyl sulfoxonium ylides is developed, providing a facile and practical route to diverse trans‐2,3‐dihydrobenzofurans with high efficiency. This protocol features mild conditions, broad substrate scope and easy to operate.