bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mesoionic Imines (MIIs): Strong Donors and Versatile Ligands for Transition Metals and Main Group Substrates
Authors: Rudolf Richard , Neuman Nicolás I. , Walter Robert R. M. , Ringenberg Mark. R. , Sarkar Biprajit 
Published: March 2022

AbstractWe report the synthesis and the reactivity of 1,2,3‐triazolin‐5‐imine type mesoionic imines (MIIs). The MIIs are accessible by a base‐mediated cycloaddition between a substituted acetonitrile and an aromatic azide, methylation by established routes and subsequent deprotonation. C=O‐stretching frequencies in MII−CO2 and −Rh(CO)2Cl complexes were used to determine the overall donor strength. The MIIs are stronger donors than the N‐heterocyclic imines (NHIs). MIIs are excellent ligands for main group elements and transition metals in which they display substituent‐induced fluorine‐specific interactions and undergo C−H activation. DFT calculations gave insights into the frontier orbitals of the MIIs. The calculations predict a relatively small HOMO–LUMO gap compared to other related ligands. MIIs are potentially able to act as both π‐donor and π‐acceptor ligands. This report highlights the potential of MIIs to display exciting properties with a huge potential for future development.
Organophotocatalytic Regioselective C−H Alkylation of Electron‐Rich Arenes Using Activated and Unactivated Alkenes
Authors: Chen Bi‐Hong , Du Yi‐Dan , Shu Wei 
Published: March 2022

AbstractDirect alkylation of the C−H bond arenes in a selective manner is a long‐standing challenge. Herein, a metal‐free photocatalytic regioselective C−H alkylation method for electron‐rich arenes with both activated and unactivated alkenes was developed. The reaction tolerates a wide range of aromatic rings with diverse substitution patterns, as well as terminal and internal alkenes, providing a general and straightforward metal‐free method for C−C bond formation from inert C−H bonds. Moreover, alkynes are also compatible to give the C−H vinylation of electron‐rich arenes.
In Vitro Biosynthesis of the [Fe]‐Hydrogenase Cofactor Verifies the Proposed Biosynthetic Precursors
Authors: Schaupp Sebastian , Arriaza‐Gallardo Francisco J. , Pan Hui‐jie , Kahnt Jörg , Angelidou Georgia , Paczia Nicole , Costa Kyle , Hu Xile , Shima Seigo 
Published: March 2022

AbstractIn the FeGP cofactor of [Fe]‐hydrogenase, low‐spin FeII is in complex with two CO ligands and a pyridinol derivative; the latter ligates the iron with a 6‐acylmethyl substituent and the pyridinol nitrogen. A guanylylpyridinol derivative, 6‐carboxymethyl‐3,5‐dimethyl‐4‐guanylyl‐2‐pyridinol (3), is produced by the decomposition of the FeGP cofactor under irradiation with UV‐A/blue light and is also postulated to be a precursor of FeGP cofactor biosynthesis. HcgC and HcgB catalyze consecutive biosynthesis steps leading to 3. Here, we report an in vitro biosynthesis assay of the FeGP cofactor using the cell extract of the ΔhcgBΔhcgC strain of Methanococcus maripaludis, which does not biosynthesize 3. We chemically synthesized pyridinol precursors 1 and 2, and detected the production of the FeGP cofactor from 1, 2 and 3. These results indicated that 1, 2 and 3 are the precursors of the FeGP cofactor, and the carboxy group of 3 is converted to the acyl ligand.
Functionalised Cofactor Mimics for Interactome Discovery and Beyond
Authors: Wilkinson Isabel V. L. , Pfanzelt Martin , Sieber Stephan A. 
Published: March 2022

AbstractCofactors are required for almost half of all enzyme reactions, but their functions and binding partners are not fully understood even after decades of research. Functionalised cofactor mimics that bind in place of the unmodified cofactor can provide answers, as well as expand the scope of cofactor activity. Through chemical proteomics approaches such as activity‐based protein profiling, the interactome and localisation of the native cofactor in its physiological environment can be deciphered and previously uncharacterised proteins annotated. Furthermore, cofactors that supply functional groups to substrate biomolecules can be hijacked by mimics to site‐specifically label targets and unravel the complex biology of post‐translational protein modification. The diverse activity of cofactors has inspired the design of mimics for use as inhibitors, antibiotic therapeutics, and chemo‐ and biosensors, and cofactor conjugates have enabled the generation of novel enzymes and artificial DNAzymes.
Tacticity Control of Cyclic Poly(3‐Thiobutyrate) Prepared by Ring‐Opening Polymerization of Racemic β‐Thiobutyrolactone
Authors: Li Hui , Ollivier Jérôme , Guillaume Sophie M. , Carpentier Jean‐François 
Published: March 2022

AbstractWe report here on the ring‐opening polymerization (ROP) of racemic β‐thiobutyrolactone (rac‐TBL), as the first chemical synthesis of poly(3‐thiobutyrolactone) (P3TB), the thioester analogue of the ubiquitous poly(3‐hydroxybutyrate) (P3HB). The ROP reactions proceed very fast (TOF >12 000 h−1 at r.t.) in the presence of various metal‐based catalysts. Remarkably, catalyst systems based on non‐chiral yttrium complexes stabilized by tetradentate amino alkoxy‐ or diamino‐bis(phenolate) ligands {ONXOR1,R2}2− (X=O, N) provide access to cyclic P3TB with either high isoselectivity (Pm up to 0.90) or high syndiotactic bias (Pr up to 0.70). The stereoselectivity can be controlled by manipulation of the substituents on the ligand platform and adequate choice of the reaction solvent and temperature as well. The cyclic polymer topology is evidenced by MALDI‐ToF MS, NMR and TGA. Highly isotactic cyclic P3TB is a semi‐crystalline material as revealed by DSC.
Carbon capture via novel Cu(II)‐DDA metal–organic frameworks‐based hybrid membranes
Authors: Raza Hamid , Yasmeen Farhat , Sarfraz Muhammad , Salman Habib Muhammad , Ba‐Shammakh Mohammad , Munawar Khurram S. , Ahmad Nazir 
Published: March 2022

AbstractAn important contributor to global warming is the incessant escalation in carbon dioxide gas (CO2) levels in the air, mainly attributed to combustion of fossil fuels. A promising strategy to regulate emission of greenhouse gases into open air is the implementation of carbon capture systems at existing and prospective carbon‐releasing infrastructures. Being a distinguished class of mesoporous materials, metal–organic frameworks (MOFs) have great potential to efficiently alleviate CO2 emissions into the atmosphere. Nanocrystals of a newly developed Cu(II)‐DDA MOF were incorporated into polysulfone (PSF) matrix in varying concentrations to fabricate hybrid membranes to enhance their carbon capture efficiency. The prepared mixed‐matrix membranes (MMMs) demonstrated better filler‐matrix interfacial adhesion, homogenous nanofiller dispersal, semicrystalline domains and thermally resistant structure. Gas adsorption tests conducted on both the Cu(II)‐DDA MOF nanocrystals and hybrid membranes indicated good adsorption capacity for CO2 as compared to N2. Experiments using cast MMMs revealed that doping the polymer matrix with MOF nanofillers increased the CO2 permeability and the CO2/N2 selectivity of the cast MMMs. In comparison to the pure PSF membrane, the CO2 permeability and CO2/N2 permselectivity of the composite membrane doped with 5 wt% Cu(II)‐DDA MOF nanocrystals were nearly doubled.
Tribological behavior of biomedical gradeUHMWPEwith graphite‐based fillers againstEBM‐Ti6Al4V pinunder various lubricating conditions
Authors: Belhamdi Hossem , Kouini Benalia , Grasso Antonio , Scolaro Cristina , Sili Andrea , Visco Annamaria 
Published: March 2022

AbstractIn this work, the wear behavior of the mechanical coupling between the biomedical polymer ultrahigh molecular weight polyethylene (UHMWPE) and the titanium–aluminum–vanadium alloy pin (Ti4Al6V) manufactured by electron beam melting (EBM) is investigated. Pure and oxidized graphite fillers is added to the UHMWPE matrix to boost the wear resistance. The tribological test is performed in dry and under the action of various lubricating media (distilled water [DW], simulated synovial fluid [SSF], and natural bovine serum [NBS]) in order to investigate their effects on wearing. The physical–mechanical characterization results show a progressive increase in wear resistance of more than 60% in the nanocomposite (UHMWPE/GO) with the addition of paraffin oil (PO) compared to the UHMWPE and higher under NBS lubricant (more than 80%). The observed wear action is reduced in the order Dry > DW > SSF ≥ NBS, thereby lowering the debris production.
Are springs hotspots of benthic invertebrate diversity? Biodiversity and conservation priority of rheocrene springs in the karst landscape
Authors: Cíbik Jakub , Beracko Pavel , Bulánková Eva , Čiamporová Zaťovičová Zuzana , Gregušová Katarína , Kodada Ján , Krno Iľja , Mišíková Elexová Emília , Navara Tomáš , Rogánska Alexandra , Derka Tomáš 
Published: March 2022

Abstract

Springs are perceived by human society as essential sources of drinking water, but on the other hand they represent peculiar and vulnerable ecosystems. They differ from other watercourses in the relatively high stability of their physicochemical conditions. As a result, springs represent ecosystems with an insular character, usually inhabited by specific aquatic communities.
Although springs are generally considered species‐rich habitats across the world, they have been outside scientific and conservation interest in the karst mountains of the Western Carpathians. This study, therefore, examined the diversity of spring benthic macroinvertebrates and compared it with that of other watercourses of the Western Carpathian riverine landscape.
The results of the study showed that, in contrast to rhithral streams, individual karst springs often had low species richness, and therefore they cannot be considered biodiversity hotspots. However, their metacommunity diversity is characterized by high taxonomic turnover, resulting in high gamma diversity. This means that the individual springs often harbour unique macroinvertebrate communities, so they are worthy of protection.
However, the present level of spring habitat protection is insufficient as even springs located in protected areas are often captured as sources of drinking water and hydromorphologically or otherwise disturbed. A simple method to evaluate the spring conservation priority (CP) was developed to find a better trade‐off between their use and protection. It uses the number of Red List, endemic and crenal taxa, as well as the total species richness at each site. Based on this classification method, 16% of the springs studied reached very high CP, 39% high CP, 33% moderate CP and 12% low CP.
The proposed management recommendations based on findings of conservation priority of the Western Carpathian karst springs can significantly contribute to their more effective protection and the creation of a legislative framework relating to spring habitat protection in general.
Fertility and early embryonic development toxicity and toxicokinetic study of KFP‐H008 in Sprague–Dawley rats
Authors: Lu Bingbing , Yue Peng , Shao Qing , Mao Lishun , Qiao Hongqun 
Published: March 2022

AbstractThe novel potassium competitive acid blocker, KFP‐H008, developed to overcome the shortcomings of proton pump inhibitors. In this study, KFP‐H008 was administered by oral gavage at doses of 0 (control), 15, 45, and 150 mg/kg to Sprague–Dawley rats (24 animals per sex per group). Body weight, food consumption, mortality, sexual cycle, mating behavior, pregnancy, sperm motility, and relative organ weights were evaluated. In a concomitant toxicokinetic (TK) study (10 animals per sex per group), plasma TK parameters and tissue distribution of KFP‐H008 were tested. There were obvious effects at the dosage of 150 mg/kg to male rats with decreases of prostate weight and lower weight gain; to female rats with lower weight gain, hair off, and lower corpus luteum count. There were no effects on litter parameters. Time to reach maximum plasma concentrations for KFP‐H008 was between 0.5 and 1.0 hr for the 15 and 45 mg/kg groups, while for the 150 mg/kg group it had a delay to 2 hr. Overall, the NOAEL of KFP‐H008 was considered to be 45 mg/kg in both genders and the TK study shows that exposure (area under the curve) of male rats was about 1,091.0 ± 530.8 μg/Lhr and to female rats was 1,030.5 ± 512.5 μg/Lhr. Administration of KFP‐H008although reaches the reproductive organs, it demonstrated no significant effects on reproductive organs, it did not affect mating, fertility, pregnancy, growth, or morphologic development.
Digital Marine: An online platform for blended learning in a marine experimental biology module, the Schmid Training Course
Authors: Flom Haley , Adamska Maja , Lami Raphaël , Gazave Eve , D'Aniello Salvatore , Schierwater Bernd , Boutet Agnès 
Published: March 2022

AbstractFor over 20 years, the Schmid Training Course (STC) has offered unique opportunities for marine biology students from European universities to learn about marine model organisms. While the topics of the course have continuously changed over the years with the advent of new research techniques and discoveries, the pedagogical approach has remained largely the same – a combination of lectures, lab practicals, and field excursions. Several life science researchers, who have taught in the STC for many years, sought to bring the course's pedagogical approach into the 21st century, and with the support of Erasmus+ Programme of the European Community funding, the Digital Marine project was developed. Digital Marine began in 2018 as an international partnership between the six research centers from which the STC instructors hail, and its main objective was to introduce a flipped, blended approach to learning and teaching with respect to established and emerging marine biological model systems. The Digital Marine platform, which covers 12 marine model organisms, is now publicly available.
Diphenyleneiodonium efficiently inhibits the characteristics of a cancer stem cell model derived from induced pluripotent stem cells
Authors: Monzur Sadia , Hassan Ghmkin , Afify Said M. , Kumon Kazuki , Mansour Hager , Nawara Hend M. , Sheta Mona , Abu Quora Hagar A. , Zahra Maram H. , Xu Yanning , Fu Xiaoyin , Seno Akimasa , Wikström Per , Szekeres Ferenc L. M. , Seno Masaharu 
Published: March 2022

AbstractDiphenyleneiodonium (DPI) has long been evaluated as an anticancer drug inhibiting NADPH oxidase, the IC50 in several cancer cell lines was reported 10 µM, which is too high for efficacy. In this study, we employed miPS‐Huh7cmP cells, which we previously established as a cancer stem cell (CSC) model from induced pluripotent stem cells, to reevaluate the efficacy of DPI because CSCs are currently one of the main foci of therapeutic strategy to treat cancer, but generally considered resistant to chemotherapy. As a result, the conventional assay for the cell growth inhibition by DPI accounted for an IC50 at 712 nM that was not enough to define the effectiveness as an anticancer drug. Simultaneously, the wound‐healing assay revealed an IC50 of approximately 500 nM. Comparatively, the IC50 values shown on sphere formation, colony formation, and tube formation assays were 5.52, 12, and 8.7 nM, respectively. However, these inhibitory effects were not observed by VAS2780, also a reputed NADPH oxidase inhibitor. It is noteworthy that these three assays are evaluating the characteristic of CSCs and are designed in the three‐dimensional (3D) culture methods. We concluded that DPI could be a suitable candidate to target mitochondrial respiration in CSCs. We propose that the 3D culture assays are more efficient to screen anti‐CSC drug candidates and better mimic tumor microenvironment when compared to the adherent monolayer of 2D culture system used for a conventional assay, such as cell growth inhibition and wound‐healing assays.
Ligand‐Controlled Site‐ and Enantioselective Carbene Insertion into Carbon‐Silicon Bonds of Benzosilacyclobutanes
Authors: Huo Jingfeng , Zhong Kangbao , Xue Yazhen , Lyu MyeeMay , Ping Yifan , Ouyang Wenbai , Liu Zhenxing , Lan Yu , Wang Jianbo 
Published: March 2022

AbstractWe report herein a highly efficient palladium‐catalyzed carbene insertion into strained Si−C bonds of benzosilacyclobutanes, which provides an efficient method to access α‐chiral silanes. With a sterically hindered ligand, carbene insertion into the C(sp3)−Si bond of benzosilacyclobutanes occurred in excellent site‐ and enantioselectivity, while C(sp2)−Si bond insertion occurred selectively with less sterically hindered ligands. Reaction mechanism, in particular the roles of the chiral ligands in controlling the site‐selectivity of the insertion reactions, are elucidated by using hybrid density functional theory.
Photoswitching Affinity and Mechanism of Multivalent Lectin Ligands
Authors: Osswald Uwe , Boneberg Johannes , Wittmann Valentin 
Published: March 2022

AbstractMultivalent receptor–ligand binding is a key principle in a plethora of biological recognition processes. Immense binding affinities can be achieved with the correct spatial orientation of the ligands. Accordingly, the incorporation of photoswitches, which can be used to reversibly change the spatial orientation of molecules, into multivalent ligands is a means to alter the binding affinity and possibly also the binding mode of such ligands. We report a divalent ligand for the model lectin wheat germ agglutinin (WGA) containing an arylazopyrazole photoswitch. This switch, which has recently been introduced as an alternative to the more commonly used azobenzene moiety, is characterized by almost quantitative E/Z photoswitching in both directions, high quantum yields, and high thermal stability of the Z isomer. The ligand was designed in a way that only one of the isomers is able to bridge adjacent binding sites of WGA leading to a chelating binding mode. Photoswitching induces an unprecedentedly high change in lectin binding affinity as determined by isothermal titration calorimetry (ITC). Furthermore, additional dynamic light scattering (DLS) data suggest that the binding mode of the ligand changes from chelating binding of the E isomer to crosslinking binding of the Z isomer.
Late‐Stage Dehydroxyazidation of Alcohols Promoted by Trifunctional Hypervalent Azido‐Iodine(III) Reagents
Authors: Yang Xiao‐Guang , Du Feng‐Huan , Li Jun‐Jie , Zhang Chi 
Published: March 2022

AbstractThe development of convenient new methods for the synthesis of organic azides is highly desirable. Herein, we report a practical method for dehydroxyazidation of alcohols via an SN2 pathway involving PPh3 and trifunctional benziodazolone‐based hypervalent azido‐iodine(III) reagents, which function as an electrophilic center, an azido source, and a base. This mild, chemoselective method was used for late‐stage azidation of structurally complex alcohols, as well as for a new synthetic route to the antiepileptic drug rufinamide. The reaction mechanism was also investigated both experimentally and computationally.
Design of Photoactive Covalent Organic Frameworks as Heterogeneous Catalyst for Preparation of Thiophosphinates from Phosphine Oxides and Thiols
Authors: Qiao Huijie , Yang Liting , Yang Xiubei , Wang Jialin , Chen Ya , Zhang Lin , Sun Wuxuan , Zhai Lipeng , Mi Liwei 
Published: March 2022

AbstractTwo new covalent organic frameworks (COFs) were synthesized from 4,4′,4′′,4′′′‐(pyrene‐1,3,6,8‐tetrayl)tetraaniline and 2,5‐dimethoxyterephthalaldehyde (Py‐DMTA‐COF) or 2′,5′‐dimethoxy‐[1,1′:4′,1′′‐terphenyl]‐4,4′′‐dicarbaldehyde (Py‐DMTPDA‐COF) under solvothermal conditions. These two COFs were further facilely developed as efficient photocatalytic platforms for the synthesis of thiophosphinates. Py‐DMTA‐COF exhibited better photocatalytic activity, broad substrate applicability, and excellent recycling capacity for the preparation of thiophosphinates from P(O)H compounds and thiols compared to Py‐DMTPDA‐COF. This methodology was further extended to the seamless gram‐scale production of target phosphorothioate derivatives. The results demonstrate that COFs can provide a robust platform for developing metal‐free, base‐free, highly efficient, and reusable heterogeneous photocatalysts for organic transformations.
Epigenetic Anti‐Cancer Treatment With a Stabilized Carbocyclic Decitabine Analogue
Authors: Traube Franziska R. , Brás Natércia F. , Roos Wynand P. , Sommermann Corinna C. , Diehl Tamara , Mayer Robert J. , Ofial Armin R. , Müller Markus , Zipse Hendrik , Carell Thomas 
Published: March 2022

Abstract5‐Aza‐2’‐deoxycytidine (Decitabine, AzadC) is a nucleoside analogue, which is in clinical use to treat patients with myelodysplastic syndrome or acute myeloid leukemia. Its mode of action is unusual because the compound is one of the few drugs that act at the epigenetic level of the genetic code. AzadC is incorporated as an antimetabolite into the genome and creates covalent, inhibitory links to DNA methyltransferases (DNMTs) that methylate 2’‐deoxycytidine (dC) to 5‐methyl‐dC (mdC). Consequently, AzadC treatment leads to a global loss of mdC, which presumably results in a reactivation of silenced genes, among them tumor suppressor and DNA damage response genes. Because AzadC suffers from severe instability, which limits its use in the clinic, a more sophisticated AzadC derivative would be highly valuable. Here, we report that a recently developed carbocyclic AzadC analogue (cAzadC) blocks DNMT1 in the AML cell line MOLM‐13 as efficient as AzadC. Moreover, cAzadC has a surprisingly strong anti‐proliferative effect and leads to a significantly higher number of double strand breaks compared to AzadC, while showing less off‐target toxicity. These results show that cAzadC triggers more deleterious repair and apoptotic pathways in cancer cells than AzadC, which makes cAzadC a promising next generation epigenetic drug.
Geography and social network influence on crowdfunding a French microbrewery
Authors: Cuénoud Thibault , Dang Rey , Houanti L’Hocine , Hikkerova Lubica 
Published: March 2022

AbstractThe objective of this article is to explore the influence of home bias and the moderating role of social networks (and more particularly family and friends—F&F) in the crowdfunding of a microbrewery in a French region (a lucrative business that uses a territorial solidarity process). We have chosen the case study as methodology to show that neither home bias nor F&F have a significant influence on amounts paid by individuals in crowdfunding. The results are specific to the case studied and are comparable to those of social enterprise. They explain but also justify the behavioural diversity crowdfunding can induce.
Design, Synthesis, and Characterization of a Novel Fluoroprobe for Live Human Islet Cell Imaging of Serotonin 5‐HT1A Receptor
Authors: Garvey Robert W. , Lacivita Enza , Niso Mauro , Duszyńska Beata , Harris Paul E. , Leopoldo Marcello 
Published: March 2022

AbstractMounting evidence suggests that the serotonin system serves in signal transmission to regulate insulin secretion in pancreatic islets of Langerhans. Among the 5‐HT receptor subtype found in pancreatic islets, serotonin receptor 1A (5‐HT1A) demonstrates a unique ability to inhibit β‐cell insulin secretion. We report the design, synthesis, and characterization of two novel fluorescent probes for the 5‐HT1A receptor. The compounds were prepared by conjugating the scaffold of the 5‐HT1A receptor agonist 8‐OH‐DPAT with two fluorophores suitable for live‐cell imaging. Compound 5a {5‐(dimethylamino)‐N‐[5‐[(8‐hydroxy‐1,2,3,4‐tetrahydronaphthalen‐2‐yl)(propyl)amino]pentyl]naphtalen‐1‐sulfonammide} showed high affinity for the 5‐HT1A receptor (Ki=1.8 nM). Fluoroprobe 5a was able to label the 5‐HT1A receptor in pancreatic islet cell cultures in a selective manner, as the fluorescence emission was significantly attenuated by co‐administration of the 5‐HT1A receptor antagonist WAY‐100635. Thus, fluoroprobe 5a showed useful properties to further characterize this unique receptor‘s role.