bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselective Amination of β‐Keto Esters Catalyzed by Chiral Calcium Phosphates
Authors: Wu Zhenwei , Krishnamurthy Suvratha , Satyanarayana Tummalapalli K. S. , Xu Jun , Yue Caizhen , Antilla Jon C. 
Published: May 2022

AbstractA catalytic enantioselective amination of β‐keto esters using (S)‐BINOL chiral calcium phosphate has been developed. The reaction produces chiral α‐amino‐β‐keto ester derivatives in most cases with moderate to excellent enantioselectivities (up to 99 %) and good yields (up to 99 %). This mild synthetic method highlights a low catalyst loading and high catalytic efficiency. When the substrate backbone was changed to 1‐tetralone‐derived β‐keto esters, unexpectedly high yields of selective redox products were obtained. The practicality of the reaction was realized by a scale‐up without any significant loss in the enantioselectivity and yield. Chiral calcium phosphate was successfully recovered and reused for four runs, indicating its stability and high catalytic activity.
Modulated Synthesis of Self‐Standing Covalent Organic Framework Films
Authors: Wang Yang , Guo Bei , Yang Tong , Zhang Zhi‐Cong , Liang Lin , Ding San‐Yuan , Wang Wei 
Published: May 2022

AbstractThe weak interaction of covalent organic framework (COF) nanoparticles makes the preparation of self‐standing COF films difficult. Herein, a modulated strategy for the facile synthesis of self‐standing COF films with good crystallinity and tunable thickness is reported. As compared with the non‐modulated approach, the modulated strategy changes the COF morphology from nanoparticles to nanofibers, enabling the facile preparation of self‐standing COF films with improved mechanical properties. The Young's modulus of the self‐standing COF film obtained via the modulated strategy could increase by 26 times. Moreover, self‐standing LZU‐8 film can be used as a membrane for efficient removal of 99 % mercury ions from aqueous solution. Our results open up a new approach to prepare self‐standing COF thin films for practical applications.
Reactions of Mesityl Azide with Ferrocene‐Based N‐Heterocyclic Germylenes, Stannylenes and Plumbylenes, Including PPh2‐Functionalised Congeners
Authors: Guthardt Robin , Oetzel Lisa , Lang Tobias , Bruhn Clemens , Siemeling Ulrich 
Published: May 2022

AbstractThe reactivity of ferrocene‐based N‐heterocyclic tetrylenes [{Fe(η5−C5H4−NSitBuMe2)2}E] (E=Ge, Sn, Pb) towards mesityl azide (MesN3) is compared with that of PPh2‐functionalised congeners exhibiting two possible reaction sites, namely the EIIand PIIIatom. For E=Ge and Sn the reaction occurs at the EIIatom, leading to the formation of N2and an EIV=NMes unit. The germanimines are sufficiently stable for isolation. The stannanimines furnish follow‐up products, either by [2+3] cycloaddition with MesN3or, in the PPh2‐substituted case, by NMes transfer from the SnIVto the PIIIatom. Whereas [{Fe(η5−C5H4−NSitBuMe2)2}Pb] and other diaminoplumbylenes studied are inert even under forcing conditions, the PPh2‐substituted congener forms an addition product with MesN3, thus showing a behaviour similar to that of frustrated Lewis pairs. The germylenes of this study afford copper(I) complexes with CuCl, including the first structurally characterised linear dicoordinate halogenido complex [CuX(L)] with a heavier tetrylene ligand L.
Chlorine‐Substituted N‐Heteroacene Analogues Acting as Organic Semiconductors for Solution‐Processed n‐type Organic Field‐Effect Transistors
Authors: Yang Bo , Wang Zilong , He Tengfei , Chen Jinqiu , Mu Zifeng , Ju Zhengkun , Lin Menglu , Long Guankui , Zhang Jing , Meng Hong , Huang Wei 
Published: May 2022

AbstractHigh performance solution processable n‐type organic semiconductor is an essential element to realize low‐cost, all organic and flexible composite logic circuits. In the design of n‐type semiconducting materials, tuning the LUMO level of compounds is a key point. As a strong electron withdrawing unit, the introduction of chlorine atom into the chemical structure can increase the electron affinity of the material and reduce the LUMO energy level. Here, a series chlorine substituted N‐heteroacene analogues of 6,7,8,9‐tetrachloro‐4,11‐bis(4‐((2‐ethylhexyl)oxy)phenyl)‐[1,2,5]thiadiazolo[3,4‐b]phenazine (O4Cl), 6,7,8,9‐tetrachloro‐4,11‐bis(4‐((2‐ethylhexyl)thio)phenyl)‐[1,2,5]thiadiazolo[3,4‐b]phenazine (S4Cl), 1,2,3,4,8,9,10,11‐octachloro‐6,13‐bis(4‐((2‐ethylhexyl)oxy)phenyl)quinoxalino[2,3‐b]phenazine (8Cl) and 12Cl have been synthesized and characterized. Solution‐processed organic field‐effect transistors (OFETs) based on these four compounds exhibit good electron mobilities of 0.04 cm2 V−1 s−1, 0.01 cm2 V−1 s−1, 2×10−3 cm2 V−1 s−1 and 3×10−3 cm2 V−1 s−1, respectively, under ambient conditions. The results suggest that these chlorine substituted π‐conjugated N‐heteroacene analogues are promising n‐type semiconductors in OFET applications.
First‐in‐Human Evaluation of Oral Denatonium Acetate (ARD‐101), a Potential Bitter Taste Receptor Agonist: A Randomized, Double‐Blind, Placebo‐Controlled Phase 1 Trial in Healthy Adults
Authors: Niethammer Andreas G. , Zheng Zhenhuan , Timmer Anjuli , Lee Tien‐Li 
Published: May 2022

AbstractPreclinical studies in animal models of obesity and inflammation have shown that oral administration of ARD‐101, a potential TAS2R agonist, reduced food intake and body weight and downregulated inflammatory cytokines. We present results from a first‐in‐human phase 1 randomized, placebo‐controlled trial that evaluated safety, pharmacokinetics, and pharmacodynamics of single or multiple ascending doses of oral ARD‐101 (40, 100, and 240 mg) in healthy adults. A total of 43 subjects were randomly assigned and dosed to ARD‐101 or placebo with 42 subjects completing the study treatment. ARD‐101 was found to be >99% restricted to the gut with minimal systemic exposure, demonstrated a favorable safety profile, and was well tolerated at all dose levels. Blood samples taken 1 hour after administration showed that subjects dosed with 240 mg of ARD‐101 had elevated circulating levels of several gut peptide hormones. It is postulated that ARD‐101 activates enteroendocrine cells to achieve its effects regulating metabolism and inflammation. The phase 1 clinical results demonstrated safety of ARD‐101 and indicated activation of gut peptide hormone release in healthy adults. Further clinical trials will evaluate ARD‐101 in patients with metabolic and inflammatory disorders.
Origin of Resonant Character in the Electron Impact Two‐Body Neutral‐Fragmentation of Methane
Authors: Sajeev Y. , Davis Daly , Kundu Sramana , Prabhudesai Vaibhav S. , Krishnakumar E. 
Published: May 2022

AbstractThe observation of peaks in the threshold region of two‐body neutral fragmentation of methane molecule, i. e., CH4→CH3+H, by low energy electron (LEE) impact has been an enigma. The prevailing explanation that this resonant behavior is due to excitation energy transfer is unsatisfactory since this process is not expected to show peaks in the cross‐sections unless there is the involvement of electron‐molecule resonances. Our first‐principles calculations now reveal that the observed peaks could be explained as due to the formation of negative ion resonances, which dominantly dissociate into two neutral fragments and a free‐electron. This case of methane is a pointer to the possibility that such reactions contribute significantly to neutral radical production from molecules by LEE impact in comparison to dissociative electron attachment, and in general could play a significant role in electron‐based chemical control.
Identification of Electrochemically Adsorbed Species via Electrochemical Microcalorimetry: Sulfate Adsorption on Au(111)
Authors: Schönig Marco , Frittmann Stefan , Schuster Rolf 
Published: May 2022

AbstractWe investigate compositional changes of an electrochemical interface upon polarization with electrochemical microcalorimetry. From the heat exchanged at a Au(111) electrode upon sulfate adsorption, we determine the reaction entropy of the adsorption process for both neutral and acidic solutions, where the dominant species in solution changes from SO42− to HSO4−. In neutral solution, the reaction entropy is about 40 J mol−1 K−1 more positive than that in acidic solution over the complete sulfate adsorption region. This entropy offset is explicable by a deprotonation step of HSO4− preceding sulfate adsorption in acidic solution, which shows that the adsorbing species is SO4* in both solutions. The observed overall variation of the reaction entropy in the sulfate adsorption region of ca. 80 J mol−1 K−1 indicates significant sulfate‐coverage dependent entropic contributions to the Free Enthalpy of the surface system.
Using quantitative eDNA analyses to accurately estimate American bullfrog abundance and to evaluate management efficacy
Authors: Everts Teun , Van Driessche Charlotte , Neyrinck Sabrina , De Regge Nico , Descamps Sarah , De Vocht Alain , Jacquemyn Hans , Brys Rein 
Published: May 2022

AbstractBiological invasions contribute now more than ever to the global homogenization of fauna and flora. Large‐scale monitoring programs are, therefore, needed to detect incipient invasions and to evaluate management interventions. As conventional monitoring methods are constrained by large costs, environmental DNA (eDNA)‐based methods are increasingly recognized as valuable monitoring tools. However, accurately estimating species abundance from eDNA concentrations in natural systems remains challenging and consequently hinders their integration in management applications. Here, we used droplet digital PCR (ddPCR) in eDNA surveys to estimate the abundance of invasive American bullfrogs (Lithobates catesbeianus). We first introduced bullfrog tadpoles in natural ponds to assess the relationship between abundances and eDNA concentrations under field conditions. Next, we combined eDNA sampling with fyke netting in naturally colonized ponds to investigate whether bullfrog eDNA concentrations can estimate bullfrog capture success and conventional abundance measures obtained via depletion sampling. Finally, we evaluated eradication measures by comparing bullfrog eDNA concentrations before and after fyke netting. We found a strong linear relationship between the numbers of introduced tadpoles and eDNA concentrations (r2 = 0.988). Bullfrog eDNA concentrations were not only linearly related to the catch‐per‐unit‐effort (r2 = 0.739), but also to conventional abundance estimates (r2 = 0.716), particularly when eDNA concentrations were standardized for pond area (r2 = 0.834) and volume (r2 = 0.888). Bullfrog tadpoles were only captured when eDNA concentrations exceeded 1.5 copies µl−1, indicating that quantitative eDNA analyses enable the localization of breeding ponds. We found a significant reduction in eDNA concentrations after fyke netting proportional to the number of captured bullfrogs. These results demonstrate that eDNA quantification is a reliable tool that accurately estimates bullfrog abundance in natural lentic systems. We show that quantitative eDNA analyses can complement the toolbox of natural resource managers and facilitate the coordination of eradication campaigns targeting alien invasive species.
Circulating levels and prognostic cut‐offs of sST2, hs‐cTnT, and NT‐proBNP in women vs. men with chronic heart failure
Authors: Vergaro Giuseppe , Gentile Francesco , Aimo Alberto , Januzzi James L. , Richards A. Mark , Lam Carolyn S.P. , de Boer Rudolf A. , Meems Laura M.G. , Latini Roberto , Staszewsky Lidia , Anand Inder S. , Cohn Jay N. , Ueland Thor , Gullestad Lars , Aukrust Pål , Brunner‐La Rocca Hans‐Peter , Bayes‐Genis Antoni , Lupón Josep , Yoshihisa Akiomi , Takeishi Yasuchika , Egstrup Michael , Gustafsson Ida , Gaggin Hanna K. , Eggers Kai M. , Huber Kurt , Gamble Greg D. , Ling Lieng H. , Leong Kui Toh Gerard , Yeo Poh Shuah Daniel , Ong Hean Yee , Jaufeerally Fazlur , Ng Tze P. , Troughton Richard , Doughty Robert N. , Devlin Gerry , Lund Mayanna , Giannoni Alberto , Passino Claudio , Emdin Michele 
Published: May 2022

AbstractAimsTo define plasma concentrations, determinants, and optimal prognostic cut‐offs of soluble suppression of tumorigenesis‐2 (sST2), high‐sensitivity cardiac troponin T (hs‐cTnT), and N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) in women and men with chronic heart failure (HF).Methods and resultsIndividual data of patients from the Biomarkers In Heart Failure Outpatient Study (BIOS) Consortium with sST2, hs‐cTnT, and NT‐proBNP measured were analysed. The primary endpoint was a composite of 1 year cardiovascular death and HF hospitalization. The secondary endpoints were 5 year cardiovascular and all‐cause death. The cohort included 4540 patients (age 67 ± 12 years, left ventricular ejection fraction 33 ± 13%, 1111 women, 25%). Women showed lower sST2 (24 vs. 27 ng/mL, P < 0.001) and hs‐cTnT level (15 vs. 20 ng/L, P < 0.001), and similar concentrations of NT‐proBNP (1540 vs. 1505 ng/L, P = 0.408). Although the three biomarkers were confirmed as independent predictors of outcome in both sexes, the optimal prognostic cut‐off was lower in women for sST2 (28 vs. 31 ng/mL) and hs‐cTnT (22 vs. 25 ng/L), while NT‐proBNP cut‐off was higher in women (2339 ng/L vs. 2145 ng/L). The use of sex‐specific cut‐offs improved risk prediction compared with the use of previously standardized prognostic cut‐offs and allowed to reclassify the risk of many patients, to a greater extent in women than men, and for hs‐cTnT than sST2 or NT‐proBNP. Specifically, up to 18% men and up to 57% women were reclassified, by using the sex‐specific cut‐off of hs‐cTnT for the endpoint of 5 year cardiovascular death.ConclusionsIn patients with chronic HF, concentrations of sST2 and hs‐cTnT, but not of NT‐proBNP, are lower in women. Lower sST2 and hs‐cTnT and higher NT‐proBNP cut‐offs for risk stratification could be used in women.
Intracerebral bleeding in donors is associated with reduced short‐term to midterm survival of heart transplant recipients
Authors: Oehler Daniel , Immohr Moritz Benjamin , Erbel‐Khurtsidze Sophia , Aubin Hug , Bruno Raphael Romano , Holst Hans Torulv , Westenfeld Ralf , Horn Patrick , Kelm Malte , Tudorache Igor , Akhyari Payam , Lichtenberg Artur , Boeken Udo 
Published: May 2022

AbstractAimThe quality of the donor heart is known to have a crucial effect on outcome after heart transplantation (HTx). Although leading to brain death in the end, the initial cause of death of the donor and its potential influences on organ quality are heterogeneous. However, it is still controversial to which extent the donor cause of death is associated with outcome or survival post‐HTx.Methods and resultsWe included all patients undergoing HTx in our centre between September 2010 and June 2021 (n = 218). Recipients were divided in five groups related to their donor cause of death: intracerebral bleeding (‘ICB’, n = 95, 44%), traumatic brain injury (‘trauma’, n = 54, 25%), hypoxic brain damage (‘hypoxic’, n = 34, 16%), cerebrovascular (‘vascular’, n = 15, 7%), or other cause (n = 20, 9%). Baseline characteristics, perioperative parameters, and survival after 30 and 90 days as well as 5 years after transplantation were collected.ResultsIntracerebral bleeding in donors compared with traumatic brain injury is associated with higher probability of need for ECLS post‐HTx (35% vs. 19%, P = 0.04) and significantly reduced survival up to 5 years post‐HTx (i.e. 1 year survival: 61% vs. 95%, P < 0.0001). Although other conditions also show significant changes in outcome and survival, the effect is strongest for ICB, where survival is also reduced compared with all other causes (1 year: 61% vs. 89%, P < 0.0001).ConclusionsIn this retrospective analysis, donor cause of death is associated with differing outcome and survival after HTx. Intracerebral bleeding hereby shows strongest decline in outcome and survival in comparison with all other causes.
Incidence and risk factors for pacemaker implantation in light‐chain and transthyretin cardiac amyloidosis
Authors: Porcari Aldostefano , Rossi Maddalena , Cappelli Francesco , Canepa Marco , Musumeci Beatrice , Cipriani Alberto , Tini Giacomo , Barbati Giulia , Varrà Guerino Giuseppe , Morelli Cristina , Fumagalli Carlo , Zampieri Mattia , Argirò Alessia , Vianello Pier Filippo , Sessarego Eugenio , Russo Domitilla , Sinigiani Giulio , De Michieli Laura , Di Bella Gianluca , Autore Camillo , Perfetto Federico , Rapezzi Claudio , Sinagra Gianfranco , Merlo Marco 
Published: May 2022

AimsThe incidence and risk factors of pacemaker (PM) implantation in patients with cardiac amyloidosis (CA) are largely unexplored. We sought to characterize the trends in the incidence of permanent PM and to identify baseline predictors of future PM implantation in light‐chain (AL) and transthyretin (ATTR) CA.Methods and resultsConsecutive patients with AL and ATTR‐CA diagnosed at participating centres (2017–2020) were included. Clinical data recorded within ±1 month from diagnosis were collected from electronic medical records. The primary study outcome was the need for clinically‐indicated PM implantation. Patients with PM (n = 41) and/or permanent defibrillator in situ (n = 13) at CA diagnosis were excluded. The study population consisted of 405 patients: 29.4% AL, 14.6% variant ATTR and 56% wild‐type ATTR; 82.5% were male, median age 76 years. During a median follow‐up of 33 months (interquartile range 21–46), 36 (8.9%) patients experienced the primary outcome: 10 AL‐CA, 2 variant ATTR‐CA and 24 wild‐type ATTR‐CA (p = 0.08 at time‐to‐event analysis). At multivariable analysis, history of atrial fibrillation (hazard ratio [HR] 3.80, p = 0.002), PR interval (HR 1.013, p = 0.002) and QRS >120 ms (HR 4.7, p = 0.001) on baseline electrocardiogram were independently associated with PM implantation. The absence of these three factors had a negative predictive value of 92% with an area under the curve of 91.8% at 6 months.ConclusionIn a large cohort of AL and ATTR‐CA patients, 8.9% received a PM within 3 years after diagnosis. History of atrial fibrillation, PR >200 ms and QRS >120 ms predicted future PM implantation.
Azolate‐Based Osmium(II) Complexes with Luminescence Spanning Visible and Near Infrared Region
Authors: Zhou Fan , Gu Muhua , Chi Yun 
Published: May 2022

AbstractMononuclear osmium(II) complexes bearing azolate chromophoric chelates constituted a new class of emitters that are isoelectronic to the iridium(III) complexes, i. e., all with low‐spin d6 electronic configuration. The high reactivity of azole toward the osmium reagent Os3(CO)12 via N−H oxidative addition gives eventual formation of various mononuclear osmium(II) complexes showing bright emission ranging from sky‐blue to near infrared. Tuning of luminescence was executed by variation of the nature and π‐conjugation of chelates, as well as changing the metal‐based electron density by further ligand substitution. One important result is the successful isolation of two classes of NIR emissive osmium(II) complexes; those with the ligand‐to‐ligand charge transfer process at the excited state seems to be less efficient than those facilitated by the distinctive intra‐ligand charge transfer process. In addition, fabrication and characterization of OLED devices were elaborated, confirming their potential to serve as efficient saturated‐red and NIR phosphors.
An Efficient and Practical Construction of S−N Bond from Aryl Thioureas and Amines under Metal‐Free Conditions
Authors: Hu Zhi‐Chao , Wu Yue‐Xiao , Ye Lei , Cui Jing‐Jing , Dong Zhi‐Bing 
Published: May 2022

AbstractAn efficient and practical construction of S−N bond from aryl thioureas and amines under mild and metal‐free conditions is reported. A series of sulfenamides was obtained smoothly from aryl thioureas and amines (mainly secondary amines) through cross dehydrogenation coupling reaction (CDC) in the presence of phenyliodine(III) diacetate. The protocol features easily available starting materials, easy and odorless performance, mild reaction conditions, good yields, and a broad substrate scope, illustrating its synthetic value for the synthesis of diverse biologically or pharmaceutically relevant compounds.
Imidazole Backbone Functionalization with Olefin Cross‐Metathesis
Authors: Angelucci Francesco , Cirillo Davide , Bjørsvik Hans‐René 
Published: May 2022

AbstractA selective and high‐rate Ru‐catalyzed cross‐metathesis reaction of alkenes with vinylimidazole is disclosed. Cross‐metathesis is known to operate less efficiently on N‐heterocycles, but through optimization by means of statistical experimental design and multiple regression, optimal reaction conditions were identified that allowed for consistent high‐yields without the need of overly complicated set‐ups or additives. The method was tested on a series of terminal alkene reagents with a variety of different functional groups and it provides the corresponding target molecules in good to high yields.
Interlaboratory Study of Polyethylene and Polydimethylsiloxane Polymeric Samplers for Ex Situ Measurement of Freely Dissolved Hydrophobic Organic Compounds in Sediment Porewater
Authors: Lotufo Guilherme R. , Michalsen Mandy M. , Reible Danny D. , Gschwend Philip M. , Ghosh Upal , Kennedy Alan J. , Kerns Kristen M. , Rakowska Magdalena I. , Odetayo Adesewa , MacFarlane John K. , Yan Songjing , Bokare Mandar 
Published: May 2022

Abstract
We evaluated the precision and accuracy of multilaboratory measurements for determining freely dissolved concentrations (Cfree) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment porewater using polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE) polymeric samplers. Four laboratories exposed performance reference compound (PRC) preloaded polymers to actively mixed and static ex situ sediment for approximately 1 month; two laboratories had longer exposures (2 and 3 months). For Cfree results, intralaboratory precision was high for single compounds (coefficient of variation 50% or less), and for most PAHs and PCBs interlaboratory variability was low (magnitude of difference was a factor of 2 or less) across polymers and exposure methods. Variability was higher for the most hydrophobic PAHs and PCBs, which were present at low concentrations and required larger PRC-based corrections, and also for naphthalene, likely due to differential volatilization losses between laboratories. Overall, intra- and interlaboratory variability between methods (PDMS vs. LDPE, actively mixed vs. static exposures) was low. The results that showed Cfree polymer equilibrium was achieved in approximately 1 month during active exposures, suggesting that the use of PRCs may be avoided for ex situ analysis using comparable active exposure; however, such ex situ testing may not reflect field conditions. Polymer-derived Cfree concentrations for most PCBs and PAHs were on average within a factor of 2 compared with concentrations in isolated porewater, which were directly measured by one laboratory; difference factors of up to 6 were observed for naphthalene and the most hydrophobic PAHs and PCBs. The Cfree results were similar for academic and private sector laboratories. The accuracy and precision that we demonstrate for determination of Cfree using polymer sampling are anticipated to increase regulatory acceptance and confidence in use of the method. Environ Toxicol Chem 2022;41:1885–1902. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.