bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Tetrapeptides, Tengupeptins A and B, Produced by Lecanicillium aphanocladii FKI‐9593 Fungal Strain
Authors: Kojima Hiroki , Watanabe Yoshihiro , Higo Mayuka , Kasuya Taiga , Nonaka Kenichi , Iwatsuki Masato , Sugawara Akihiro 
Published: December 2024

ABSTRACTThe discovery of novel natural products through the exploration of distinct microorganisms is crucial for advancing drug discovery research. In this study, we focus on a unique environmental resource, microbial masses known as “Tengu‐no‐Mugimeshi.” From the culture broth of Lecanicillium aphanocladii FKI‐9593, isolated from Tengu‐no‐Mugimeshi collected at Mount Kurohime, Nagano Prefecture, Japan, we report the isolation of two novel tetrapeptides, tengupeptins A (1) and B (2), as well as the known compound oosporein. Structural analysis revealed that tengupeptins are composed of four amino acids: L‐glutamic acid for 1 (or L‐pyroglutamic acid for 2), (Z)‐α,β‐didehydro tryptophan (ΔZTrp), (Z)‐α,β‐didehydro‐phenylalanine (ΔZPhe), and L‐aspartic acid. Notably, dehydroamino acids containing an aromatic moiety conjugated with a double bond connected via two or more consecutive linkages are rare in natural products, and the ΔZTrp‐ΔZPhe fragment represents the first example. The isolation of secondary metabolites from filamentous fungi inhabiting unique environments, such as Tengu‐no‐Mugimeshi, is anticipated to offer significant potential for future research.
Structural and Functional Mimicry of the Antimicrobial Defensin Plectasin by Analogues with Engineered Backbone Composition
Authors: Harmon Thomas W. , Song Junming , Gulewicz Andrew J. , Di Y. Peter , Horne W. Seth 
Published: December 2024

AbstractThe threat posed by bacteria resistant to common antibiotics creates an urgent need for novel antimicrobials. Non‐ribosomal peptide natural products that bind Lipid II, such as vancomycin, represent a promising source for such agents. The fungal defensin plectasin is one of a family of ribosomally produced miniproteins that also exert antimicrobial activity via Lipid II binding. Made up entirely of canonical amino acids, these molecules are potentially more susceptible to degradation by protease enzymes than non‐ribosomal counterparts. Here, we report the development of proteomimetic variants of plectasin through the systematic incorporation of artificial backbone connectivity in the domain. An iterative secondary‐structure‐based design scheme yields a variant with a tertiary fold indistinguishable from the prototype natural product, potent activity against Gram positive bacteria, and low mammalian cell toxicity. Backbone modification is shown to improve oxidative folding efficiency of the disulfide‐rich scaffold as well as resistance to proteolytic hydrolysis. These results broaden the scope of design strategies toward protein mimetics as well as folds and biological functions possible in such agents.
Chemically Robust Cationic Porous Organic Polymer (POP) for Selective Detection and Removal of ReO4− as a Surrogate of Radioactive 99TcO4−
Authors: Biswas Kishalay , Dam Gourab K. , Mahanta Supriti , Roy Anirban , Vinod Parmar Saurabh , Avasare Vidya , Ghosh Sujit K. 
Published: December 2024

AbstractThe efficient removal of 99TcO4− from alkaline nuclear waste is vital for optimizing nuclear waste management and safeguarding the environment. However, current state‐of‐the‐art sorbent materials are constrained by their inability to simultaneously achieve high alkali resistance, rapid adsorption kinetics, large adsorption capacity, and selectivity. In this study, we synthesized a urea‐rich cationic porous organic polymer, IPM‐403, which demonstrates exceptional chemical stability, ultrafast kinetics (~92 % removal within 30 seconds), high adsorption capacity (664 mg/g), excellent selectivity, along with multiple‐cycle recyclability (up to 7 cycles), making it highly promising for the removal of ReO4− (surrogate of 99TcO4−) from nuclear wastewater. Notably, after exposure to 1 M NaOH solution for 24 hours, IPM‐403 maintained a high adsorption capacity of 421.3 mg/g for ReO4−. Furthermore, IPM‐403 acts as an efficient sensor for ReO4−, exhibiting a turn‐on response and a detection limit as low as 78.8 ppb.
Tuning the Duplex Stability of DNA Oligonucleotides Containing Metal‐Mediated Base Pairs of Imidazole‐Derived Nucleobases
Authors: Bardehle Carla , Müller Jens 
Published: December 2024

AbstractTwo artificial imidazole‐derived nucleobases, HQIm (3H‐imidazo[4,5‐f]quinolin‐5‐ol) and CaIm (imidazole‐4‐carboxylate), were introduced into short DNA duplexes to systematically investigate their thermal stability upon metal ion coordination. Metal‐mediated base pairs are formed with the 3d metal ions CoII, NiII and ZnII, as well as with the lanthanoid ions EuIII and SmIII, which induce a thermal stabilization of up to 8 °C upon binding. The latter are the first lanthanoid‐mediated base pairs involving only four donor atoms that result in a significant duplex stabilization. For the 3d metal ions, the increase in DNA melting temperature is in agreement with the trend in complex stability according to the Irving‐Williams series. The duplex stabilization upon metal‐mediated base pair formation depends on the identity of the artificial base pair, enabling discrimination between metal ions by systematic design of the duplex. Further, the influence of pH on the stability of selected duplexes was studied, revealing a linear relation between pH and the formation of HQIm–NiII–HQIm base pairs and allowing to induce a distinct stabilization between 1 °C and 28 °C. Regarding EuIII‐mediated base pairs, an acidic pH can be utilized to disturb their formation, presumably by promoting the coordination of EuIII to the DNA backbone.
Selective Decarboxylative Fluorination of β‐Keto Acids in Aqueous Media: 19F‐NMR‐Assisted Batch Optimization and Transfer to Continuous Flow
Authors: Cermjani Egzon , Deckers Christoph , Maskos Michael , Rehm Thomas H. 
Published: December 2024

AbstractThe selective decarboxylative fluorination of 3‐oxo‐3‐phenylpropionic acid is used as a benchmark reaction to optimize it under biocompatible conditions in batch and to transfer it to continuous flow mode. The reaction conditions are varied with respect to temperature, fluorinating reagents, inorganic base additives, and pH, as these parameters have been identified as having a significant impact on the process. The formation of the products and any by‐products is analyzed using gas chromatography (GC) and 19F nuclear magnetic resonance spectroscopy (NMR). Once optimal conditions have been determined, the reaction is carried out using an automated continuous laboratory synthesis system that features a mesostructured capillary reactor and an integrated 19F‐NMR spectrometer for real‐time monitoring of the reaction. The work presented here represents the initial phase of a multi‐step continuous flow process that will include additional biocatalyzed downstream reactions in future applications.
Enhancing Epoxy Composites with Graphene and Graphene Oxide: Thermal and Mechanical Insights
Authors: Wilczewski Sławomir , Nowak Zdzisław , Maj Michał , Osial Magdalena , Minikayev Roman , Giersig Michael 
Published: December 2024

AbstractThis paper shows the graphene and graphene oxide nanoflakes as the 0.1, 0.5, 1, 2, and 4 wt.% reinforcement of epoxy‐resin matrix to enhance the thermal and mechanical characteristics of the composite. Experimental measurement of the glass transition temperature and thermal expansion coefficient indicated that the addition of nanostructural filler improving the glass transition temperature about ~12 °C for nanocomposite filled carbon‐based nanoparticles for both heating and cooling cycles compared to the bare epoxy resin. Young's elastic modulus measured by nanoindentation and the stress versus strain curves for different weight fractions of graphene nanoflakes additives during uniaxial compression and tension considered were obtained from the experiments. The distributions of logarithmic strain field for the transverse, axial and shear components on the nanocomposites sample surfaces, during the uniaxial tension process for quasi‐static strain rates, were analyzed. The tensile strengths show improvement for nanocomposites with less than 1 % weight fraction of carbon‐based nanoparticles. The compressive yield stress increased to a maximal value (at the recorded peak on the curve) for an epoxy nanocomposite having 2 wt.% oxidized graphene flakes, where both parameters were enhanced with the oxidized form of graphene for the more effective dispersion in the epoxy resin matrix over the bare graphene filler.
Interplay between Spinmerism and Spin‐Orbit Coupling for a d2 Metal Ion in an Open‐Shell Ligand Field
Authors: Roseiro Pablo , Shah Ashini , Yalouz Saad , Robert Vincent 
Published: December 2024

AbstractRecent theoretical studies have shown that placing a spin‐crossover ion in a field of radical ligands can induce local superpositions of spin states (see Ref. [1,2]). The stability of this phenomenon, termed spinmerism, is called into question when spin‐orbit coupling is included. Thus, we investigate the competition between spinmerism and spin‐orbit coupling in a d2 metal ion with two radical ligands. Our results show that competition between spinmerism and spin‐orbit coupling can induce distinct states which may potentially open new avenues for quantum technologies.
Antimicrobial Potential of a Formazanate‐Based Mercury(II) Complex: In Vitro‐ and In Silico‐Based Insights
Authors: Birara Sunita , Kumar Yadav Vinay , Kumar Jena Abinash , Bhattacharyya Sudipta , Metre Ramesh K. 
Published: December 2024

AbstractHerein, we present a distorted square pyramidal mercury complex, [HgII(L)Cl] (1), based on a quinoline‐substituted formazan ligand LH[3‐Cyano‐1,5‐(quinolin‐8‐yl)formazan], which was evaluated for its anti‐bacterial activity in vitro. Complex 1 was prepared by refluxing 3‐Cyano‐1,5‐(quinolin‐8‐yl)formazan ligand and mercury chloride(II) in equimolar quantity and was characterized utilizing a range of analytical methods, including single crystal X‐ray diffraction (SCXRD) technique. The crystal packing in complex 1 has been elucidated using supramolecular investigations, which have shown the presence of fascinating Hg−Cl⋅⋅⋅Hg intermolecular spodium bonds of the order 3.348 Å. The antimicrobial activity of the formazanate‐based mercury(II) complex (1) was assessed against Gram‐positive (Staphylococcus aureus and Bacillus subtilis) and Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) bacterial pathogens. In addition, the plausible therapeutic target of the formazanate‐based mercury(II) complex was determined through in silico pharmacophore‐guided rational drug designing approach. Based on the in silico results, a conceivable molecular mechanism of the observed bactericidal action of the newly synthesized [HgII(L)Cl] complex (1) has also been suggested.
FeCu−N6−C Diatomic Sites Catalyst for the Boosted Oxygen Reduction Reactions in Zinc‐Air Batteries
Authors: Sang Longrun , Zhu Haosheng , Zhang Shan , Wang Shipeng , Jiao ZiPan , Wang Yunsi , Zhang Peng , Hu Riming , Liu Bingxin , Li YongCheng 
Published: December 2024

AbstractDue to the high catalytic activity and stability for oxygen reduction reaction, N‐coordinated Fe−Cu dual‐metal doped carbon material (FeCu−N−C) is considered to be one of the promising electrode materials for metal‐air battery and fuel cells. Herein, FeCu−N−C dual‐metal catalysts was synthesized by an adsorption‐calcination strategy. The prepared FeCu−N−C exhibited high activity and stability both in alkaline and acidic media. In alkaline/acid medium, the half‐wave potential reaches to 0.90/0.80 V, which is better than Fe−N−C catalyst. The power density for FeCu−N−C in zinc‐air battery reaches to 220 mW cm−2 and shows high electrochemical stability for more than 600 hours in charge/discharge cycles, much higher than 130 hours for Pt/C (40 %) and 100 hours for Fe−N−C. Density‐functional theory calculations showed that the FeCu−N−C dual‐metal catalysts got lower overpotential of 0.50 V than Fe−N−C (0.53 V), which improved the ORR activity. The results are helpful for the deep understanding of high‐performance diatomic catalysts.
Visible‐Light‐Induced Tandem Cyclization of 1,7‐Enynes to Access Phenanthridin‐6(5H)‐Ones Using a Polydimethylsiloxane (PDMS) Based Microreactor
Authors: Ravi Dharavath , Prasad Vadla Shiva , Rao Vadithya Ranga , Krishna Silari Mohana , Kumar Chelukalapally Anil , Saha Biswajit , Adiyala Praveen Reddy 
Published: December 2024

AbstractWe report an organophotoredox‐catalyzed visible‐light‐induced tandem cyclization of 1,7‐enynes with diaryliodoniumtriflates has been established leading to Phenanthridin‐6(5H)‐one derivatives under metal‐free conditions. This transformation is initiated by visible light induced aryl radical formation from diaryliodoniumtriflates, followed by its regioseletive addition to the acrylate moiety of 1,7‐enynes then undergoes intramolecular 6‐exo‐dig cascade radical annulation and which is terminated by single electron oxidation along with proton abstraction. This effective, sustainable and metal‐free protocol exhibits a broad substrate scope and excellent tolerability towards various functional groups in good to excellent yields. Further implementation of a batch protocol to continuous flow protocol utilizing polydimethylsiloxane (PDMS) based microreactor exhibits its efficiency.
Dynamic Modeling of LLC Resonant Converter Using Extracted Two‐Harmonic Approximation and Comparative Analysis With Other Approaches
Authors: Abbasi Ahmad , Ghayebloo Abbas 
Published: December 2024

ABSTRACTResonant converters are widely used in various applications due to their wide input voltage range, high efficiency, and high power density. The mathematical modeling of these converters has great importance because they have both AC and DC states, simultaneously, which poses challenges for controller design. In this paper, a dynamic mathematical model of the LLC resonant converter is extracted by developing the common first harmonic approximation (FHA) model to a two‐harmonic approximation (THA) model, and its accuracy is compared with other conventional models, including the FHA, the dynamic pharos (DP), non‐linear mathematical models. As a reference model, circuit experimental model has been used for comparison. The comparison metric is the sum of squared errors in transient and steady‐state modes, expressed as a percentage of the steady‐state peak value. Furthermore, the output of the mathematical models and simulations is evaluated against practical results from a prototype.
Efficient Input‐Output Feedback Linearizing Control of BLDC Drives
Authors: Joshi Dhaval , Deb Dipankar , Giri Ashutosh K. , Colak Ilhami 
Published: December 2024

ABSTRACTElectrically driven unmanned aerial vehicles (UAVs) are gaining popularity due to use in industrial, military, and civil applications. The UAVs have to execute complicated maneuvers in the air requires accurate control of the BLDC motor propeller systems. In this study, we propose easy to implement field‐oriented adaptive input‐output feedback linearizing control (AIOFL) for controlling propellers as per demand of flight controller. This study aims to compare the proposed field‐oriented AIOFL with usual six step control architecture with a focus on the typical back‐electromotive force (back‐EMF) shapes featured in the propeller motor. The proposed control architecture that does not only regulate speed and torque of the propeller with acceptable torque ripple but it also estimates the rotor magnetic flux and the stator resistance of the BLDC motor to know about stator/rotor condition monitoring, motor fault detection, and temperature rise. To ensure reliable operation in all operational conditions, closed loop stability of proposed speed controller is analyzed based on the Lyapunov method. Particle swarm optimization (PSO) is utilized to accurately tune the PI controller since the trial‐and‐error technique used to choose the PI controller gains resulted in the low stability and poor transient response of the controller. Finally, comprehensive numerical and experimental tests are performed and compared with conventional field‐oriented control to evaluate the effectiveness and robustness of the proposed control system.
The Interplay Between Visual Traits and Forest in Bumblebee Communities Across Sweden
Authors: Tichit Pierre , Kendall Liam , Olsson Peter , Taylor Gavin , Rau Christoph , Caplat Paul , Smith Henrik G. , Baird Emily 
Published: December 2024

ABSTRACTUnderstanding how ecological communities assemble in relation to natural and human‐induced environmental changes is critical, particularly for communities of pollinators that deliver essential ecosystem services. Despite widespread attention to interactions between functional traits and community responses to environmental changes, the importance of sensory traits has received little attention. To address this, we asked whether visual traits of bumblebee communities varied at large geographical scales along a habitat gradient of increased tree cover. Because trees generate challenging light conditions for flying insects, in particular a reduced light intensity, we hypothesised that differences in tree cover would correlate with shifts in the visual and taxonomical composition of bumblebee communities. We quantified 11 visual traits across 36 specimens from 20 species of bumblebees using micro‐CT and optical modelling of compound eyes and ocelli, and investigated how these traits scale with body size. Using an inventory of bumblebee communities across Sweden and our visual trait dataset, we then explored how visual traits (both absolute and relative to body size) differed in relation to tree cover. We found positive shifts of the community weighted means of visual traits along the increasingly forested habitat gradient (facet diameter, inter‐ommatidial angle, eye parameter of the compound eye and alignment of the three ocelli) that were consistent regardless of body size, while other traits decreased when more forest was present in the landscape (facet number). These functional patterns were associated with differences in the abundance of six common species that likely explains the community‐wide shift of visual traits along the habitat gradient. Our study demonstrates the interaction between vision, habitat and community assembly in bumblebees, while highlighting a promising research topic at the interface between sensory biology and landscape ecology.
Authentication of Virgin Olive Oil Based on Untargeted Metabolomics and Chemical Markers
Authors: Dou Xinjing , N´Diaye Katharina , Harkaoui Said El , Willenberg Ina , Ma Fei , Zhang Liangxiao , Li Peiwu , Matthäus Bertrand 
Published: December 2024

ABSTRACTVirgin extra olive oil as a high‐value edible oil is a potential object of adulteration. Refined camellia oil (RCO) could be one of the most challenging potential adulterants of olive oil to detect due to its high similarity in the fatty acid composition. In this study, an untargeted metabolomics strategy based on data from ultra‐performance liquid chromatography‐electrospray ionization‐quadrupole‐time of flight (UPLC‐ESI‐qTOF) measurements combined with statistical methods was applied to identify the unauthorized addition of RCO to extra virgin olive oil (EVOO). Untargeted fingerprints of the olive oil and RCO could be classified into two groups via unsupervised principal component analysis (PCA) that shows the significant difference of the fingerprints of polar components extracted from olive oil and CAOs, respectively. Orthogonal partial least squares‐discriminant analysis (OPLS‐DA) and volcano plots were used to identify markers with significant difference between these two oils. The results show that 927 and 780 features (positive and negative ESI modes), respectively, were higher regulated in virgin extra olive oil, whereas 439 and 479 features, respectively, were higher regulated in RCO. From these features, 28 markers for olive oil and 7 markers for CAO were tentatively identified. Further adulteration experiments showed that virgin extra olive oil containing more than 15% RCO could be distinguished from the olive oil by this untargeted UPLC‐ESI‐qTOF measurement, followed by unsupervised PCA. Furthermore, camelliagenin A (519.3695/12.22, [M + FA − H]−) could still be detected when EVOOs were mixed with at least 5% CAO.
Facile Access to Phospholene Fused Polycycles through Intramolecular Alder‐Ene Reaction of Phosphole Sulfides
Authors: Geng Dingjin , Ma Aoyang , Dong Zhenhua , Chai Jinkui 
Published: December 2024

AbstractWe have developed a simple, metal‐free annulation of phosphole sulfides through intramolecular Alder‐ene reaction involving a 1,6‐enyne component. This atom‐efficient cyclization pathway provides phospholene fused polycycles with high yields and excellent regioselectivity. The 1,6‐enyne cyclization of phosphole sulfides with a phenyl group affords structurally complex benzo‐fused bicyclo[3.3.0] scaffolds. Meanwhile, phosphole sulfides with a naphthyl group produce naphtho‐fused bicyclo[4.3.0] skeletons, as well as structurally complex [2+2] cycloaddition products.
Concise Four‐Component Synthesis of Solid‐State Fluorescent α‐Sulfenylated Enaminones
Authors: Hendrik Schmitz Gereon , Kramer Wiebke , Karl Leonard , Ganter Christian , Müller Thomas J. J. 
Published: December 2024

AbstractAcid chlorides, alkynes, amines, and N‐thiosuccinimides react in a consecutive four‐component alkynylation‐addition‐sulfenylation sequence to give α‐sulfenylated enaminones in good to excellent yields. The terminal sulfenylation step is catalyzed by Yb(OTf)3 and both N‐arylthiosuccinimides and N‐alkylthio succinimides can be successfully employed. Most products are solid‐state luminescent with fluorescence quantum yields up to 84 % and lifetimes up to 4.9 ns. Additionally, TD‐DFT calculations rationalize the electronic structure of the absorption characteristics of the dyes.