bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fischer Carbene Complexes: A Glance at Two Decades of Research on Higher‐Order Cycloaddition Reactions
Authors: Feliciano Alberto , Vázquez Juan L. , Benítez‐Puebla Luis J. , Velazco‐Cabral Iván , Cruz Cruz David , Delgado Francisco , Vázquez Miguel A. 
Published: April 2021

AbstractThe structure of Fischer carbene complexes (FCCs) is electron deficient. If bearing an α,β‐unsaturated system, it can generate a wide variety of compounds by undergoing many different transformations, including higher‐order cycloadditions. The latter are described as pericyclic reactions in which more than six electrons participate. These reactions have been employed in various areas of organic synthesis, resulting in highly selective compounds with a broad range of scaffolds. The first studies on higher‐order cycloadditions involving FCCs frequently yielded competing byproducts. Many groups have attempted to increase selectivity by exploring distinct reaction conditions, reagents and co‐catalysts (e. g., metal‐mediated cycloadditions). The present review is the first to focus exclusively on using higher‐order cycloadditions involving FCCs to synthesize carbocycles and heterocycles. Based on two decades of reports, an analysis is made of the main aspects of the mechanisms proposed for higher‐order cycloadditions and the structural diversity obtained by the substituent effect.
Nematic Triphenyltriazine Triesters and the Induction of the Columnar Mesophase by Fluorine Substitution
Authors: Vieira André A. , Farias Giliandro , Costa Wallison C. , Eccher Juliana , Bechtold Ivan H. , Durola Fabien , Bock Harald 
Published: April 2021

AbstractWhereas their para homologs are not mesogenic, the disk‐shaped triphenyltriazine meta‐trialkylesters obtained via trimerization of 3‐cyanobenzoic alkylester, which are configurationally more flexible, exhibit a monotropic nematic mesophase. Introduction of fluorine atoms into the alkyl chains or into the phenyl moieties leads to the appearance of an enantiotropic columnar mesophase. If fluorine is introduced both in the chains and in the phenyl moieties, only a monotropic mesophase remains. Fluorination of either the alkyl chains or the aromatic core, but not both, appears thus as a simple means of inducing or stabilizing columnar self‐assembly in disk‐shaped systems. As the homeotropically alignable columnar mesophase can thus be made to persist at room temperature, as energies higher than 3 eV of the first excited triplet state are computed in agreement with the value reported for the parent arene, and as they are not fluorescent themselves, these compounds are of promise as aligning host matrices for blue‐emitting TADF devices with improved light outcoupling. Dilution of a columnar with a nonmesogenic homolog induces the nematic state, indicating that the nanoscopic make‐up of both mesophases is closely related.
Self‐Assembled Multivalent Ag‐SR Coordination Polymers with Phosphatase‐Like Activity
Authors: Cao Ying‐Juan , Yao Mei‐Xia , Prins Leonard J. , Ji Rui‐Xue , Liu Ning , Sun Xiang‐Ying , Jiang Yun‐Bao , Shen Jiang‐Shan 
Published: April 2021

AbstractWe show herein the phosphatase‐like catalytic activity of coordination polymers obtained after adding Ag+‐ions to thiols bearing hydrophobic alkyl chains terminated with a 1,4,7‐triazacyclononane (TACN) group. The subsequent addition of Zn2+ ‐ions to the self‐assembled polymers resulted in the formation of multivalent metal coordination polymers capable of catalysing the transphosphorylation of an RNA‐model compound (2‐hydroxypropyl‐4‐nitrophenyl phosphate, HPNPP) with high reactivity. Analysis of a series of metal ions showed that the highest catalytic activity was obtained when Ag+‐ions were used as the first metal ions to construct the backbone of the coordination polymer through interaction with the ‐SH group followed by Zn2+‐ions as the second metal ions complexed by the TACN‐macrocycle. Furthermore, it was demonstrated that the catalytic activity could be modulated by changing the length of the hydrophobic alkyl chain.
Integrated Photoresponsive Alkaline Earth Metal Coordination Networks: Synthesis, Topology, Photochromism and Photoluminescence Investigation
Authors: You Zi‐Xin , Wang Chen , Xiao Yao , Guan Qing‐Lin , Li Jin‐Xiao , Xing Yong‐Heng , Gao Hong‐Wei , Sun Li–Xian , Bai Feng‐Ying 
Published: April 2021

AbstractPhotoresponsive materials are a key part of the age of smart technology that have potential in a broad range of applications. Coordination networks (CNs) are widely used due to their designability and stability. In this work, three novel alkaline earth metal coordination networks (AEM‐CNs): [Mg(CMNDI)(H2O)2], [Ca(CMNDI)(H2O)2]⋅H2O, and [Sr(CMNDI)(H2O)(DMF)] with fsl, cds, and scn topology nets were synthetized via N,N’‐bis(carboxymethyl)‐1,4,5,8‐naphthalenediimide (H2CMNDI); the scn net is not found in the Reticular Chemistry Structure Resource or ToposPro. The reusable and sensitive photochromic properties of the three CNs enable them to be used as secret inks or ultraviolet detectors. In addition, the CNs also exhibited reusable photoluminescent turn‐off toward the drug molecules, balsalazide disodium (Bal.) and colchicine (Col.), with good limits of detection of 0.16 and 0.70 μM. To the best of our knowledge, this is the first study of a fluorescence sensor for Bal. Thus, the AEM‐CNs provide a design idea for integrated photoresponsive materials that could be further improved in the near future by further study.
Unraveling the Guest‐Induced Switchability in the Metal‐Organic Framework DUT‐13(Zn)**
Authors: Felsner Bodo , Bon Volodymyr , Evans Jack D. , Schwotzer Friedrich , Grünker Ronny , Senkovska Irena , Kaskel Stefan 
Published: April 2021

AbstractThe switching mechanism of the flexible framework Zn4O(benztb)1.5 (benztb=N,N,N’,N’‐benzidine tetrabenzoate), also known as DUT‐13, was studied by advanced powder X‐ray diffraction (PXRD) and gas physisorption techniques. In situ synchrotron PXRD experiments upon physisorption of nitrogen (77 K) and n‐butane (273 K) shed light on the hitherto unnoticed guest‐induced breathing in the MOF. The mechanism of contraction is based on the conformationally labile benztb ligand and accompanied by a reduction in specific pore volume from 2.03 cm3 g−1 in the open‐pore phase to 0.91 cm3 g−1 in the contracted‐pore phase. The high temperature limit for adsorption‐induced contraction of 170 K, determined by systematic temperature variation of methane adsorption isotherms, indicates that the DUT‐13 framework is softer than other mesoporous MOFs like DUT‐49 and does not support the formation of overloaded metastable states required for negative gas‐adsorption transitions.
Energetics of Competing Chiral Supramolecular Polymers
Authors: Ayzac Virgile , Dirany Mohammed , Raynal Matthieu , Isare Benjamin , Bouteiller Laurent 
Published: April 2021

AbstractChirality can have unexpected consequences including on properties other than spectroscopic. We show herein that a racemic mixture of bis‐urea stereoisomers forms thermodynamically stable supramolecular polymers that result in a more viscous solution than for the pure stereoisomer. The origin of this macroscopic property was probed by characterizing the structure and stability of the assemblies. Both racemic and non‐racemic bis‐urea stereoisomers form two competing helical supramolecular polymers in solution: a double and a single helical structure at low and high temperature, respectively. The transition temperature between these assemblies, as probed by spectroscopic and calorimetric analyses, is strongly influenced by the composition (by up to 70 °C). A simple model that accounts for the thermodynamics of this system, indicates that the stereochemical defects (chiral mismatches and helix reversals) affect much more the stability of single helices. Therefore, the heterochiral double helical structure predominates over the single helical structure (whilst the opposite holds for the homochiral structures), which explains the aforementioned higher viscosity of the racemic bis‐urea solution. This rationale constitutes a new basis to tune the macroscopic properties of the increasing number of supramolecular polymers reported to exhibit competing chiral nanostructures.
Systematic Access of Ternary Organotetrel‐Copper Chalcogenide Clusters by [PhTE3]3− Anions (T=Si, Sn; E=S, Se)
Authors: Rinn Niklas , Guggolz Lukas , Hou Han Yu , Dehnen Stefanie 
Published: April 2021

AbstractFragmentation reactions of organotetrel chalcogenide heteroadamantane‐type clusters [(PhT)4E6] (T/E=Si/S (1); Si/Se; Sn/S, and Sn/Se) by addition of the corresponding sodium chalcogenide gave salts of the general formula Na3[PhTE3], with T/E=Si/S (2); Si/Se (3); Sn/S (A); Sn/Se (4). Reaction of these salts with [Cu(PPh3)3Cl] gave a series of organotetrel–copper chalcogenide clusters [(CuPPh3)6(PhTE3)2] with T/E=Si/S; (5), Si/Se (6), Sn/S (7) and Sn/Se (8). Compounds 5–8 share a common structural motif with two intact {PhTE3} units coordinating a Cu6 moiety, which was previously reported with other ligands, and for the Sn and Ge congeners only. If the Sn/Se reaction system was allowed to crystallize more slowly, single crystals of compound [(CuPPh3)6(PhSnSe3)3Cu3SnSe] (9) were obtained, which are based on a larger cluster structure. Hence, 9 might form from 8 through incorporation of additional cluster fragments. The experimentally and quantum chemically determined optical properties were compared to related clusters.
Multi‐objective Deng's grey incidence analysis, orthogonal optimization, and artificial neural network modelling in hot‐maceration‐assisted extraction of African cucumber leaves (Momordica balsamina)
Authors: Olalere Olusegun Abayomi , Gan Chee‐Yuen , Adedeji Paul Adeola , Olalere Modupeola Elizabeth , Aljbour Nawzat 
Published: April 2021

AbstractDue to the inherent multiple response characteristics in many biological and separation processes, parameter optimization and modelling is usually a daunting task. The integration of Deng's grey incidence model (GRA) and Taguchi optimization (TM) therefore helps in transforming multiple quality characteristics into a single response presented as the grey relational grade (GRG). This was applied to optimize the multiple quality response characteristics in the maceration‐assisted extraction of African cucumber leaves. Two responses and five design factors were selected with L16(25) layout using signal‐to‐noise ratio as a point prediction feature. Under the optimized conditions, the optimum total phenolic content and antioxidant capacity of 0.8569 mg/ml gallic acid equivalence and 0.9259 mg/ml were achieved, respectively. The mass ratio was the highest contributor (38.2%), whereas the maceration time presented the least contribution (9.8%) to the cumulative response grade (GRG). In the neural network analysis, three models were deployed: Levenberg Marquardt backpropagation neural network (LMNN), gradient descent with adaptive learning rate neural network (GDALRNN), and the resilient back‐propagation neural network (RPNN). A better prediction of hold‐out data was achieved with the GDALRNN model, generating lesser absolute deviation error (MADGDALRNN = 0.099), root mean square error (RMSEGDALRNN = 0.1033), relative mean bias error (rMBEGDALRNN =  − 0.24), and highest computational time (CTGDALRNN = 8.8), which is expected of an effective model. Based on the GRG and the signal‐to‐noise ratio, the optimum conditions and the neural network model succinctly provided a benchmark for future assessment of complex relationship among extraction variables, which could form the basis for a potential future scale‐up applications.
Structural, Electronic, and Optical Properties of Hexagonal XC6 (X=N, P, As, and Sb) Monolayers
Authors: Zhang Wei , Chai Changchun , Fan Qingyang , Song Yanxing , Yang Yintang 
Published: April 2021

AbstractBased on first‐principles calculations, a novel family of two‐dimensional (2D) IV–V compounds, XC6 (X=N, P, As and Sb), is proposed. These compounds exhibit excellent stability, as determined from the cohesive energies, phonon dispersion analysis, ab initio molecular dynamics (AIMD) simulations, and mechanical properties. In this type of structure, the carbon atom is sp2 hybridized, whereas the X (N, P, As and Sb) atom is nonplanar sp3 hybridized with one 2pz orbital filled with lone pair electrons. NC6, PC6, AsC6 and SbC6 monolayers are intrinsic indirect semiconductors with wide bandgaps of 2.02, 2.36, 2.77, and 2.85 eV (based on HSE06 calculations), respectively. After applying mechanical strain, PC6, AsC6 and SbC6 monolayers can be transformed from indirect to direct semiconductors. The appropriate bandgaps and well‐located band edge positions make XC6 monolayers potential materials for photocatalytic water splitting. XC6 family members also have high absorption coefficients (∼105 cm−1) in the ultraviolet region and higher electron mobilities (∼103 cm2 V−1 s−1) than many known 2D semiconductors.
Critical considerations for the positive memory‐posttraumatic stress disorder model
Authors: Contractor Ateka A. , Banducci Anne N. , Weiss Nicole H. 
Published: April 2021

AbstractPosttraumatic stress disorder (PTSD) includes changes in processes such as encoding and retrieval for both traumatic and positive memories. However, most work has predominantly focused on traumatic memories. Thus, Contractor and colleagues proposed a Positive Memory‐PTSD model, which highlighted potential benefits associated with and mechanisms underlying positive memory retrieval/processing among individuals reporting PTSD symptoms. To enhance research on and clinical impacts of this model, the current review provides critical considerations for the Positive Memory‐PTSD model. Drawing from emerging research and clinical observations, we (i) clarify that the model addresses specific versus overgeneral positive memories; (ii) underscore the importance of considering the heterogeneity in, and transitionary nature of, affect processes following positive memory retrieval; and (iii) highlight the rationale for considering trauma type/count and co‐occurring conditions, as potential moderators of relations between positive memory processing and PTSD. Hereby, we provide an updated Positive Memory‐PTSD model and implications for positive memory interventions drawing from this model.
A systematic review of the implementation of psychological therapies in acute mental health inpatient settings
Authors: Evlat Gamze , Wood Lisa , Glover Naomi 
Published: April 2021

AbstractObjectivesResearch has demonstrated that psychological therapies are not routinely delivered in acute mental health inpatient settings despite being recommended by the National Institute for Health and Care Excellence (NICE) guidelines. This study aimed to identify the barriers and facilitators to implementing psychological therapies in acute mental health inpatient settings.MethodsA systematic review and narrative synthesis was undertaken. Primary studies were included if they examined the implementation of a NICE recommended psychological therapy in acute psychiatric inpatient settings and were of any study design. Four databases were searched for eligible studies (MEDLINE, CINAHL Plus, PsycINFO and Embase) and Google Scholar.ResultsA total of 16 studies (a mixture of both qualitative and quantitative methodologies) were included in the review, and the majority evaluated the implementation of Cognitive Behaviour Therapy. Overall, the literature was deemed to be of poor to moderate quality. The main barriers to the implementation of psychological therapy were the busy nature of the ward, multi‐disciplinary professionals not being suitability trained and the acute nature of service users mental health difficulties. Facilitators to implementation included the adaptation of interventions to be specifically delivered in the acute inpatient setting, training of multi‐disciplinary professionals, leadership support with the delivery of psychological therapies and prioritising the therapeutic relationship.ConclusionsThere is a requirement for senior management to prioritise the implementation of psychological therapies and update clinical guidelines to describe modifications necessary to implement psychological therapies in acute inpatient settings. Future research should improve their methodological quality and continue to develop the evidence base of brief psychological therapies in acute inpatient settings.
Long‐term detection of clodronate in equine plasma by liquid chromatography–tandem mass spectrometry
Authors: Garcia Patrice , Perot Isabelle , Loup Benoit , Balssa Frederic , Jaubert Murielle , Delcourt Vivian , Dujardin Chris , Popot Marie‐Agnes , Bailly‐Chouriberry Ludovic 
Published: April 2021

AbstractClodronate is a non‐nitrogen‐containing bisphosphonate drug approved in equine veterinary medicine. Clodronate is prohibited for use in competition horses; therefore, to set up an appropriate control, detection times and screening limits are required. The quantitative method in plasma consisted of addition of chloromethylene diphosphonic acid as internal standard. Automated sample preparation comprised a solid phase extraction with weak anion exchange properties on microplate. After methylation of the residue with trimethyl orthoacetate, analysis was conducted by high‐performance liquid chromatography–tandem mass spectrometry. Using a weighting factor of 1/(concentration)2, good linearity was observed in the range of 1 to 500 ng/ml, with low limits of detection and quantification of 0.5 and 1 ng/ml, respectively. Precision and accuracy determined at four concentrations were satisfactory, with an error percentage less than 15%. Absence of carry‐over and good stability of clodronic acid in plasma after a long‐term storage at −20°C were verified. The method was successfully applied to the quantification of clodronic acid in plasma samples from horses administered with a single intramuscular administration of Osphos® at a mean dose of 1.43 ± 0.07 mg/kg. The observed detection time will be verified in a clinical population study conducted in diseased horses.
Estimation of breeding probability can make monitoring data more revealing: a case study of amphibians
Authors: Cruickshank Sam S. , Bergamini Ariel , Schmidt Benedikt R. 
Published: April 2021

AbstractMonitoring programs serve to detect trends in the distribution and abundance of species. To do so, monitoring programs often use static state variables. Dynamic state variables that describe population dynamics might be more valuable because they allow for a mechanistic understanding of the processes that lead to population trends. We fit multistate occupancy models to data from a country‐wide multispecies amphibian occupancy monitoring program and estimated occupancy and breeding probabilities. If breeding probabilities are determinants of occupancy dynamics, then they may serve in monitoring programs as state variables that describe dynamic processes. The results showed that breeding probabilities were low and that a large proportion of the populations had to be considered to be non‐breeding populations (i.e., populations where adults are present but no breeding occurs). For some species, the majority of populations were non‐breeding populations. We found that non‐breeding populations have lower persistence probabilities than populations where breeding occurs. Breeding probabilities may thus explain trends in occupancy but they might also explain other ecological phenomena, such as the success of invasive species, which had high breeding probabilities. Signs of breeding, i.e., the presence of eggs and larvae, were often hard to detect. Importantly, non‐breeding populations also had low detection probabilities, perhaps because they had lower abundances. We suggest that monitoring programs should invest more in the detection of life history stages indicative of breeding, and also into the detection of non‐breeding populations. We conclude that breeding probability should be used as a state variable in monitoring programs because it can lead to deeper insights into the processes driving occupancy dynamics.
Stereoselective Synthesis of 4,5‐Dihydroisoxazole Derivatives from 1,1‐Dicyanocyclopropanes and Hydroxylamine Hydrochloride
Authors: Zhang Yue , Xin Junhu , Wang Cunde 
Published: April 2021

AbstractAn efficient approach was developed for the synthesis of 4,5‐dihydroisoxazole derivatives from substituted 1,1‐dicyano‐cyclopropanes and hydroxylamine hydrochloride in ethanol through FeCl3‐catalyzed cascade addition reactions. This procedure gives a useful method to afford stereoselectively poly‐substituted 4,5‐dihydroisoxazoles in good yields.
Small molecule natural compound targets the NF‐κB signaling and ameliorates the development of osteoarthritis
Authors: Xu Zhu , Shen Zhong‐hai , Wu Bin , Gong Sui‐liang , Chen Bin 
Published: April 2021

AbstractOsteoarthritis (OA) is a multifactorial and chronic disease describing the destruction of cartilage that can lead to defects in the elderly. There is currently no practical strategy that can reverse the OA process. Here, we describe nepetin, a small natural compound with extracellular matrix (ECM) and inflammation regulating functions. In this study, we investigated the therapeutic effects of nepetin on interleukin‐1β (IL‐1β)‐induced inflammation in mice chondrocyte and OA model. In chondrocytes, treatment with nepetin inhibited the overexpression of pro‐inflammatory cytokines and mediators induced by IL‐1β. Moreover, pretreatment or posttreatment with nepetin also reduced the ECM catabolism and enhanced the ECM anabolism. Mechanistically, nepetin suppressed NF‐κB signaling pathway in IL‐1β stimulated chondrocyte. Meanwhile, our molecular docking studies indicated nepetin had a powerful binding capacity to p65. Furthermore, nepetin showed a protective and therapeutic effect on the mouse OA model. To sum up, this study indicated nepetin had a new potential therapeutic option in OA.
Baricitinib: From Rheumatoid Arthritis to COVID‐19
Authors: Assadiasl Sara , Fatahi Yousef , Mosharmovahed Banafsheh , Mohebbi Bahareh , Nicknam Mohammad Hossein 
Published: April 2021

AbstractBaricitinib is a JAK1/2 inhibitor that was first approved for treating moderate to severe rheumatoid arthritis (RA) but that later showed considerable efficacy in the control of exaggerated inflammatory responses that occur in a wide range of diseases. There is a growing body of evidence, obtained from clinical trials and case reports, demonstrating clinical and paraclinical improvement in patients following administration of baricitinib including RA, systemic lupus erythematosus, psoriasis, atopic dermatitis, alopecia areata, interferon‐mediated autoinflammatory diseases, graft‐versus‐host disease, diabetic kidney disease, and, recently, coronavirus disease‐19. However, despite overall encouraging results, many adverse effects have been observed in baricitinib‐treated patients, ranging from simple infections to increased risk of malignancies, particularly in long‐term use. The significant efficacy of baricitinib, versus the probable adverse effects, urge further investigation before establishing it as a part of standard therapeutic protocols. Here, we have provided a review of the studies that have used baricitinib for treating various inflammatory disorders and summarized the advantages and disadvantages of its administration.