bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Heterocycles through Denitrogenative Cyclization of Triazoles and Benzotriazoles
Authors: Li Wenbo , Zhang Junliang 
Published: May 2020

AbstractDuring the past few decades, there has been considerable growth in the development of denitrogenative reactions of triazole skeletons to construct valuable cyclic compounds, particularly heterocycles. Despite the inherent difficulty of the ring‐opening of triazole derivatives, many novel and efficient approaches have arisen in this area mainly with the use of transition metal (such as rhodium, palladium, silver, copper) catalysis, photolysis, or free radical mediated reactions. Generally, these procedures begin with the ring‐opening of 1,2,3‐triazoles or benzotriazoles followed by N2extrusion and subsequent diverse transformations, which enable the rapid synthesis of various heterocycles in a single step. To avoid overlap with other related reviews, this minireview covers the recent advances in the denitrogenative cyclization of 1,2,3‐triazoles since 2016 and the denitrogenative cyclization of benzotriazoles since 2012.
A Lamellar MWW Zeolite With Silicon and Niobium Oxide Pillars: A Catalyst for the Oxidation of Volatile Organic Compounds
Authors: Schwanke Anderson Joel , Balzer Rosana , Wittee Lopes Christian , Motta Meira Débora , Díaz Urbano , Corma Avelino , Pergher Sibele 
Published: May 2020

AbstractIn this work, an MWW‐type zeolite with pillars containing silicon and niobium oxide was synthesized to obtain a hierarchical zeolite. The effect of niobium insertion in the pillaring process was determined by combining a controllable acidity and accessibility in the final material. All pillared materials had niobium occupying framework positions in pillars and extra‐framework positions. The pillared material, Pil‐Nb‐4.5 with 4.5 wt % niobium, did not compromise the mesoporosity formed by pillaring, while the increase of niobium in the structure gradually decreased the mesoporosity and ordering of lamellar stacking. The morphology of the pillared zeolites and the niobium content were found to directly affect the catalytic activity. Specifically, we report on the activity of the MWW‐type zeolites with niobium catalyzing the gas‐phase oxidation of volatile organic compounds (VOCs), which is an important reaction for clean environmental. All produced MWW‐type zeolites with niobium were catalytically active, even at low temperatures and low niobium loading, and provided excellent conversion efficiencies.
A Dimeric Chromium(II) Pincer as an Electron Shuttle for N=N Bond Scission
Authors: Labrum Nicholas S. , Cabelof Alyssa C. , Caulton Kenneth G. 
Published: May 2020

AbstractReduction of the bis‐pyrazolyl pyridine complex [CrL]2 with 4 KC8, followed by addition of one azobenzene (overall mole ratio 1:4:1), PhNNPh, transfers reducing equivalents to three azobenzenes, to form [K3Cr(PhNNPh)3]. This has three κ2 PhNNPh2− ligands and K+ bound to nitrogen atoms of azobenzene. When the stoichiometry is modified to 1:4:3, the product is changed to [K2CrL(PhNNPh)2], which has C2 symmetry except for the intimate ion pairing of two K+ ions to reduced azobenzene nitrogen atoms, and to pyrazolate and phenyl rings. The origin of the observed delivery of reducing equivalents to several, not to a single N=N bond, is traced to the resistance of the one‐electron‐reduced substrate to receiving a second electron, and is thus a general phenomenon. [CrL]2 alone is shown to be a two‐electron reductant towards benzo[c]cinnoline (BCC) resulting in a product of formula [Cr2L2(BCC)], in which the reducing equivalents originate purely from CrII. An analogous study of the reaction of [CrL]2 with azobenzene yields [Cr2L2(PhNNPh)(THF)], an adduct in which one THF has displaced one of four hydrazide nitrogen/Cr bonds. Together these illustrate different modes for the Cr2L2 unit to bind and reduce the N=N bond. Collectively, these results show that two divalent Cr, without added K0, have the ability to reduce the N=N bond. Further KC8 reduction of preformed Cr2L2(RNNR) inevitably gives products in which K+ stabilizes the charge in the increasingly electron‐rich nitrogen atoms, in a phenomenon which mimics proton coupled electron transfer: K+ performs the role of H+. A least‐squares fit of the two singly reduced DFT structures shows that the only major change is a re‐orientation of one of the two phenyl rings in order to avoid repulsion with potassium but to still allow interaction of that phenyl π system with K+. This shows both the impact of K+, being modest to nitrogen/chromium interactions, but nevertheless accommodating some π donation of phenyl to potassium. Finally, delivering increasing equivalents of KC8 leads to complete cleavage of the N=N bond, and both N bind to three CrII. The varied impacts of the K+ electrophile on NN multiple bond reduction is discussed.
Biohybrid Conjugated Polymer Materials for Augmenting Energy Conversion of Bioelectrochemical Systems
Authors: Zhou Xin , Lv Fengting , Huang Yiming , Liu Libing , Wang Shu 
Published: May 2020

AbstractBioelectrochemical systems (BESs) provide favorable opportunities for the sustainable conversion of energy from biological metabolism. Biological photovoltaics (BPVs) and microbial fuel cells (MFCs) respectively realize the conversion of renewable solar energy and bioenergy into electrical energy by utilizing electroactive biological extracellular electron transfer, however, along with this energy conversion progress, relatively poor durability and low output performance are challenges as well as opportunities. Advances in improving bio‐electrode interface compatibility will help to solve the problem of insufficient performance and further have a far‐reaching impact on the development of bioelectronics. Conjugated polymers (CPs) with specific optical and electrical properties (absorption and emission spectra, energy band structure and electrical conductivity) afforded by π‐conjugated backbones are conducive to enhancing the electron generation and output capacity of electroactive organisms. Furthermore, the water solubility, functionality, biocompatibility and mechanical properties optimized through appropriate modification of side chain provide a more adaptive contact interface between biomaterials and electrodes. In this minireview, we summarize the prominent contributions of CPs in the aspect of augmenting the photovoltaic response of BPVs and power supply of MFCs, and specifically discussed the role of CPs with expectation to provide inspirations for the design of bioelectronic devices in the future.
N‐Heterocyclic Carbenes Reduce and Functionalize Copper Oxide Surfaces in One Pot
Authors: Veinot Alex J. , Al‐Rashed Abrar , Padmos J. Daniel , Singh Ishwar , Lee Dianne S. , Narouz Mina R. , Lummis Paul A. , Baddeley Christopher J. , Crudden Cathleen M. , Horton J. Hugh 
Published: May 2020

AbstractBenzimidazolium hydrogen carbonate salts have been shown to act as N‐heterocyclic carbene precursors, which can remove oxide from copper oxide surfaces and functionalize the resulting metallic surfaces in a single pot. Both the surfaces and the etching products were fully characterized by spectroscopic methods. Analysis of surfaces before and after NHC treatment by X‐ray photoelectron spectroscopy demonstrates the complete removal of copper(II) oxide. By using 13C‐labelling, we determined that the products of this transformation include a cyclic urea, a ring‐opened formamide and a bis‐carbene copper(I) complex. These results illustrate the potential of NHCs to functionalize a much broader class of metals, including those prone to oxidation, greatly facilitating the preparation of NHC‐based films on metals other than gold.
Dibenzothiophenesulfilimines: A Convenient Approach to Intermolecular Rhodium‐Catalysed C−H Amidation
Authors: Antoni Patrick W. , Mackenroth Alexandra V. , Mulks Florian F. , Rudolph Matthias , Helmchen Günter , Hashmi A. Stephen K. 
Published: May 2020

AbstractA sulfilimine‐based Group 9 transition‐metal‐catalysed C−H amidation procedure is reported. Dibenzothiophene‐based sulfilimines were shown to constitute a class of novel amidation reagents which enable the transfer of a wide range of N‐sulfonyl and N‐acyl moieties. It was demonstrated that sulfilimines, which are easily accessible from cheap reagents, are safe‐to‐handle and represent broadly applicable amidation reagents. The dibenzothiophene can be recycled after use. The C−H amidation was shown to proceed with high selectivity and gave the mono‐amidated products, mostly in good to excellent yields.
QTc interval evaluation in patients with right bundle branch block or bifascicular blocks
Authors: Erkapic Damir , Frommeyer Gerrit , Brettner Niklas , Sözener Korkut , Crijns Harry J. G. M. , Seyfarth Melchior , Hamm Christian W. , Bogossian Harilaos 
Published: May 2020

AbstractBackgroundThe right bundle branch block (RBBB) and the bifascicular blocks affect QRS duration in the right precordial leads, which are usually used for QT interval determination. Up to now, there is no clear recommendation how to determine QT interval in patients with RBBB or bifascicular block.HypothesisThe hypothesis of the present study was to evaluate the feasibility of a simple formula for RBBB and bifascicular block correction, thereby making it easier to determine the QTc interval.MethodsIn patients with intrinsic QRS duration <120 ms, artificial RBBB with either left posterior (LPFB) or left anterior fascicular block (LAFB), created by left ventricular pacing maneuvers, were corrected using the Bogossian formula (QTm) and afterward were heart rate corrected (QTmc). Heart rate correction was performed using different heart rate formulas in comparison to each other. The QTmc intervals were compared in each patient with the QTc interval during intrinsic rhythm.ResultsA total of scheduled 71 patients were included in this prospective multicenter observational comparative study. Compared to intrinsic QTc interval, the mean ΔQTmc interval by combination of the Bogossian and the Hodge formulas was −3 ± 24 ms in RBBB + LPFB (P = .44) and −6 ± 25 ms in RBBB + LAFB (P = .15). The Bogossian formula showed a significant deviation from the actual QTc interval with both the Bazett and the Fridericia formulas.ConclusionIn combination with the Hodge formula, the Boggosian formula delivered the best results in comparing the true QTc interval in narrow QRS with the QTmc interval in the presence of a bifascicular block.
Divergent Synthesis of Novel Cylindrocyclophanes that Inhibit Methicillin‐Resistant Staphylococcus aureus (MRSA)
Authors: Freudenreich Julien J. , Bartlett Sean , Robertson Naomi S. , Kidd Sarah L. , Forrest Suzie , Sore Hannah F. , Galloway Warren R. J. D. , Welch Martin , Spring David R. 
Published: May 2020

AbstractThe cylindrocyclophanes are a family of macrocyclic natural products reported to exhibit antibacterial activity. Little is known about the structural basis of this activity due to the challenges associated with their synthesis or isolation. We hypothesised that structural modification of the cylindrocyclophane scaffold could streamline their synthesis without significant loss of activity. Herein, we report a divergent synthesis of the cylindrocyclophane core enabling access to symmetrical macrocycles by means of a catalytic, domino cross‐metathesis‐ring‐closing metathesis cascade, followed by late‐stage diversification. Phenotypic screening identified several novel inhibitors of methicillin‐resistant Staphylococcus aureus. The most potent inhibitor has a unique tetrabrominated [7,7]paracyclophane core with no known counterpart in nature. Together these illustrate the potential of divergent synthesis using catalysis and unbiased screening methods in modern antibacterial discovery.
Design and Synthesis of New Pyrazole‐Based Heterotricycles and their Derivatization by Automated Library Synthesis
Authors: Fricero Prisca , Bialy Laurent , Czechtizky Werngard , Méndez María , Harrity Joseph P. A. 
Published: May 2020

AbstractSmall‐molecule heterocycles bearing orthogonal functionality have the potential to deliver diverse structural motifs that aid the drug‐discovery effort. This work highlights how a readily assembled N‐hydroxyethyl pyrazole trifluoroborate offers rapid access to architecturally distinct 5‐6‐6‐ and 5‐7‐6‐fused tricyclic compounds. This chemistry is not only amenable to single compound synthesis, but also to high‐throughput experimentation. It gives easy access to diverse compound arrays with various physicochemical and ADME profiles by fully automated library synthesis. The combination of the high‐throughput experimentation with rapid testing of the compounds in an integrated physicochemical and ADME profiling workflow allows accelerated design of novel lead compounds in drug‐discovery projects.
Therapy after cyclin‐dependent kinase inhibition in metastatic hormone receptor‐positive breast cancer: Resistance mechanisms and novel treatment strategies
Authors: Sharifi Marina N. , Anandan Apoorva , Grogan Patrick , O’Regan Ruth M. 
Published: May 2020

Endocrine therapy has been the standard of care for patients with metastatic hormone receptor (HR)‐positive, HER2‐negative breast cancer since the 1970s, improving survival while avoiding the toxicities associated with cytotoxic chemotherapy. However, all HR‐positive tumors ultimately develop resistance to endocrine therapy. Cyclin‐dependent kinase 4 and 6 (CDK4/6) inhibitors have more recently become an important component of the management of this breast cancer subtype, significantly delaying time to the disease progression and improving survival when combined with endocrine therapy. However, as with endocrine therapy alone, treatment resistance remains a universal phenomenon. As more women receive CDK4/6 inhibitors as part of their treatment, the management of de novo and acquired resistance to combined CDK4/CDK6 inhibitor plus endocrine therapy regimens has emerged as an important clinical challenge. Several resistance mechanisms have been described, including alterations in the CDK4/6/cyclin D complex or its major effector retinoblastoma protein (pRb), bypass signaling through other cyclin/CDK complexes and activation of upstream signaling pathways, in particular the PI3K/mTOR pathway, but robust biomarkers to predict resistance remain elusive, and the role for continuing CDK4/6 inhibitors after progression remains under investigation. Novel strategies being evaluated in clinical trials include the continuation of CDK4/6 inhibitors through progression, as well as triplet therapy combinations with PI3K inhibitors or immune checkpoint inhibitors.
Functionalization of Tile‐based DNA Nanocages with Gold Nanoparticles (AuNPs) to Form AuNP Cluster‐DNA Cage Hybrids
Authors: Yu Yang , Lei Yunxiang , Dong Qiang , Li Yulin 
Published: May 2020

AbstractAttaching functional nanomaterials onto tile‐based DNA nanocages to form hybrids consisting of DNA nanocages and nanomaterial clusters with well‐defined compositions might not only integrate the functions of each component, but also potentially lead to new emergent properties and applications. Herein, we report a general and facile hybridization‐driven approach for functionalizing tile‐based nanocages with gold nanoparticles (AuNPs) to form AuNP cluster‐DNA cage hybrids. AuNP tetramer‐DNA tetrahedron hybrids and AuNP octamer‐DNA octahedron complexes have been successfully fabricated. Our hybridization‐based strategy could in principle be extended to fabricate various hybrids with designable compositions and structures due to the diversity of tile‐based nanocages and the great variety of functional nanomaterials that could be modified with DNA, which should hold the promise of greatly promoting the research of bio/nanoassembly.
Pharmacokinetics of Gepotidacin in Renal Impairment
Authors: Hossain Mohammad , Tiffany Courtney , Raychaudhuri Aparna , Nguyen Dung , Tai Guoying , Alcorn Harry , Preston Richard A. , Marbury Thomas , Dumont Etienne 
Published: May 2020

AbstractGepotidacin is a novel triazaacenaphthylene bacterial topoisomerase inhibitor. In this phase 1, nonrandomized, open‐label, parallel‐group, multicenter, multipart study, the pharmacokinetics, safety, and tolerability of a single intravenous (IV) dose of gepotidacin 750 mg over 2 hours were evaluated in subjects with normal renal function, in those with moderate and severe renal impairment, and in end‐stage renal disease (ESRD) on and not on dialysis. Administration of IV gepotidacin 750 mg was safe and generally tolerated in the study subjects. Dosing in severe renal impairment with and without hemodialysis resulted in significant increases in plasma drug levels and decreases in clearance. The geometric mean elimination half‐life (t½) was minimally impacted (range 9.45 to 11.5 hours) in all the renal‐impairment groups relative to normal renal function. Regardless of renal function, urine gepotidacin concentrations remained considerably high over a 12‐hour period. Saliva concentrations displayed a linear relationship with plasma concentrations. The t½ in saliva was not impacted in the moderate‐impairment and ESRD subjects and was comparable to t½ in plasma. Over a 4‐hour dialysis, approximately 6% of the gepotidacin dose was removed. Overall, subjects with severe renal impairment and ESRD with and without hemodialysis may require adjustment in dose or dosing frequency.
Using image object recognition to increase biomass in red clover (Trifolium pratense L.) breeding
Authors: Sindic Caleb M.T. , Riday Heathcliffe 
Published: May 2020

AbstractPhenotyping in forage legume breeding can be time consuming and resource intensive. With computation advances and computational power cost reductions, utilizing artificial intelligence in automated phenotyping is becoming feasible for even resource limited forage legume breeding programs. Here we report on the use of machine learning to train a neural network to identify and isolate red clover plants from digital images of space planted red clover nurseries. Challenges to red clover plant identification included: 1) plants were grown with a grass companion; and 2) plants were close enough to each other so that plants often overlapped each other in the digital images. To estimate biomass yield a second neural network was trained using machine learning to count leaves per plant among identified red clover plants from the plant classification neural network. The two neural networks were validated on six red clover digital image sets taken on red clover space plant nurseries. Average neural network plant classification success rates were measured at 94.6% across the six digital image sets. Neural network red clover leaf counts were correlated with human visual biomass scores at r2 = 0.528. We conclude that automated phenotyping based on digital image analysis of red clover breeding nurseries is currently feasible. We further conclude that additional phenotypic traits could be obtained on identified red clover plants from such images sets.
Aqueous Calcium‐Ion Battery Based on a Mesoporous Organic Anode and a Manganite Cathode with Long Cycling Performance
Authors: Cang Ruibai , Zhao Chunlin , Ye Ke , Yin Jinling , Zhu Kai , Yan Jun , Wang Guiling , Cao Dianxue 
Published: May 2020

AbstractAqueous batteries have attracted increasing and extensive attention, owing to their high safety, low cost, and low toxicity. These factors have become increasingly important, given the current focus on the rapid development of green energy technologies. In particular, multivalent‐ion batteries are emerging as alternatives to lithium‐ion batteries. Unfortunately, magnesium and aluminum ions have high polarization strengths that are unfavorable for electrode materials. In contrast, calcium‐ion batteries successfully avoid the problem of high polarization. Herein, an aqueous calcium‐ion battery (CIBs) based on mesoporous silica SBA‐15 with a two‐dimensional hexagonal through‐hole structure is reported. The poly(3,4,9,10‐perylentetracarboxylic diimide) (PPTCDI) organic material supported on SBA‐15 is used as the anode and displays a capacity of 201 mAh g−1, with a stable cycling performance of 95 % capacity retention after 1500 cycles. SBA‐15@PPTCDI‖Ca2MnO4 aqueous CIBs demonstrate a high energy density of 130.6 Wh kg−1 in the cell voltage range from 0.0 to 1.8 V, with a high capacity and excellent cycling stability. As the anode material, SBA‐15@PPTCDI shows special bonding of redox electrons that leads to its highly stable performance, which paves the way for addressing the shortcomings of traditional organic electrode materials. The localization and delocalization of the redox electron offers additional voltage stability, which is another important advantage for practical applications. This study highlights the potential of organic electrode materials for applications in aqueous multivalent‐metal‐ion batteries.
Mini review: The FDA‐approved prescription drugs that induce ovulation in women with ovulatory problems
Authors: Sun Chunlei , Rong Xi , Cai Yongqin , Qiu Song , Farzaneh Maryam 
Published: May 2020

AbstractInfertility is defined as not being able to become pregnant after 12 months or more of unprotected sexual intercourse. Female infertility as a serious health issue can result from ovulation disorders, menstrual cycle problems, structural problems, and environmental factors. Ovulation occurs once a month between the time of menarche and menopause. The release of a mature egg from the ovary is controlled with the hypothalamic‐pituitary‐ovarian axis. Several hormones such as gonadotropin‐releasing hormone (GnRH), FSH (follicle‐stimulating hormone), LH (luteinizing hormone), estrogen, and progesterone play fundamental roles in the ovulation process. Both FSH and LH are the main treatment for women with ovulation disorders. Depending on the reasons for infertility, several different types of treatment are available for infertile women. Fertility drugs as an important part of treatment work like the natural hormones to treat infertility. Several fertility drugs can regulate ovulation and the release of an egg from the ovary in women with polycystic ovary syndrome (PCOS) or undergoing in vitro fertilization (IVF) treatment. This mini‐review is about the FDA‐approved prescription drugs that induce ovulation in women with ovulatory problems.
Human and monkey infant attention to dynamic social and nonsocial stimuli
Authors: Maylott Sarah E. , Paukner Annika , Ahn Yeojin A. , Simpson Elizabeth A. 
Published: May 2020

AbstractThe present study explored behavioral norms for infant social attention in typically developing human and nonhuman primate infants. We examined the normative development of attention to dynamic social and nonsocial stimuli longitudinally in macaques (Macaca mulatta) at 1, 3, and 5 months of age (N = 75) and humans at 2, 4, 6, 8, and 13 months of age (N = 69) using eye tracking. All infants viewed concurrently played silent videos—one social video and one nonsocial video. Both macaque and human infants were faster to look to the social than the nonsocial stimulus, and both species grew faster to orient to the social stimulus with age. Further, macaque infants’ social attention increased linearly from 1 to 5 months. In contrast, human infants displayed a nonlinear pattern of social interest, with initially greater attention to the social stimulus, followed by a period of greater interest in the nonsocial stimulus, and then a rise in social interest from 6 to 13 months. Overall, human infants looked longer than macaque infants, suggesting humans have more sustained attention in the first year of life. These findings highlight potential species similarities and differences, and reflect a first step in establishing baseline patterns of early social attention development.