bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multistage Stimulus‐Responsive Room Temperature Phosphorescence Based on Host–Guest Doping Systems
Authors: Tian Yu , Yang Jie , Liu Zhenjiang , Gao Mingxue , Li Xiaoning , Che Weilong , Fang Manman , Li Zhen 
Published: July 2021

AbstractCompared with inorganic long‐lasting luminescent materials, organic room temperature phosphorescent (RTP) ones show several advantages, such as flexibility, transparency, solubility and color adjustability. However, organic RTP materials close to commercialization are still to be developed. In this work, we developed a new host–guest doping system with stimulus‐responsive RTP characteristics, in which triphenylphosphine oxide (OPph3) acted host and benzo(dibenzo)phenothiazine dioxide derivatives as guests. Turn‐on RTP effect was realized by mixing them together through co‐crystallization or grinding, in which the efficient energy transfer from host to guest and the strong intersystem crossing (ISC) ability of the guest have played significant role. Further on, multistage stimulus‐responsive RTP characteristics from grinding to chemical stimulus were achieved via introducing pyridine group into the guest molecule. In addition, the anti‐counterfeiting printings were realized for these materials through various methods, including stylus printing, thermal printing and inkjet printing, which brings RTP materials closer to commercialization.
Revision of the Unstable Picrotoxinin Hydrolysis Product
Authors: Tong Guanghu , Shenvi Ryan A. 
Published: July 2021

AbstractThe plant metabolite picrotoxinin (PXN) is a widely used tool in neuroscience for the identification of GABAergic signaling. Its hydrolysis in weakly alkaline media has been observed for over a century and the structure of the unstable hydrolysis intermediate was assigned by analogy to the degradation product picrotoxic acid. Here we show this assignment to be in error and we revise the structure of the hydrolysis product by spectroscopic characterization in situ. Counterintuitively, hydrolysis occurs at a lactone that remains closed in the major isolable degradation product, which accounts for the longstanding mistake in the literature.
Single‐nucleotide polymorphisms that uniquely identify cultivars of avocado (Persea americana)
Authors: Kämper Wiebke , Trueman Stephen J. , Cooke Jade , Kasinadhuni Naga , Brunton Aaron J. , Ogbourne Steven M. 
Published: July 2021

PremiseProgeny of avocado (Persea americana) are highly variable due to high levels of heterozygosity. Breeding programs need molecular resources to allow the assessment of genetic differences and the selection of genotypes. Polymorphisms that uniquely identify different avocado cultivars provide a valuable tool to accelerate avocado research and development, including, for example, genotype selection.MethodsA double‐digest restriction site–associated DNA sequencing (ddRADseq) approach was used to screen 10 avocado cultivars for single‐nucleotide polymorphisms (SNPs). The fragments were size selected with Blue Pippin and PCR using universal Illumina primers, and catalog tags were then created with de novo alignment using Stacks software. Catalog tags were tabulated and filtered to identify alleles unique to each cultivar.ResultsA total of 104 million sequences were collected, and 52 homozygous SNPs were identified that uniquely distinguished nine avocado cultivars. The cultivars Carmen Hass and Hass have a strong genetic similarity and no homozygous SNPs distinguishing these cultivars could be identified; therefore, both cultivars were grouped together.DiscussionThe resource described here for cultivars of P. americana presents a new and significant molecular resource that can enable targeted genotype selection, paternity analysis, germplasm genotyping, pollination dynamics investigation, and crop improvement.
Motivational affordances and survival of new askers on social Q&A sites: The case of Stack Exchange network
Authors: Kang Minhyung 
Published: July 2021

AbstractSocial question‐and‐answer (Q&A) sites are platforms where users can freely ask, share, and rate knowledge. For the sustainable growth of social Q&A sites, maintaining askers is as critical as maintaining answerers. Based on motivational affordances theory and self‐determination theory, this study explores the influence of the design elements of social Q&A sites (i.e., upvotes, downvotes, edits, user profile, and comments) on the survival of new askers. In addition, the moderating effect of having an alternative experience is examined. Online data on 25,000 new askers from the top five Q&A sites in the Technology category of the Stack Exchange network are analyzed using logistic regression. The results show that the competency‐ and autonomy‐related design features of social Q&A sites motivate new askers to continue participating. Surprisingly, having an alternative experience shows a negative moderating effect, implying that alternative experiences increase switching costs in the Stack Exchange network. This study provides valuable insights for administrators of social Q&A sites as well as academics.
Output feedback predictive control for discrete quasilinear systems with application to spacecraft flying‐around
Authors: Zhang Da‐Wei , Liu Guo‐Ping 
Published: July 2021

AbstractThis paper considers a spacecraft flying‐around problem modeled by discrete quasilinear system under sight coordinate, which can be regarded as an output tracking for discrete quasilinear system. An output feedback predictive control scheme is presented to deal with the flying‐around task. This scheme contains the design of output feedback and the optimization of tracking performance. On the one hand, the completely parametric form of output feedback based on generalized Sylvester equation is developed to stabilize the closed‐loop nominal system. On the other hand, a cost function, aimed to measure tracking performance, is optimized by the design of predictive control such that tracking performance is ensured. Further analysis proposes a necessary and sufficient condition based on Lyapunov method to maintain both bounded stability and tracking performance of the closed‐loop system caused by output feedback predictive control. Compared with the existing method, a numerical simulation is given to richly demonstrate the effectiveness and feasibility of the proposed control scheme.
Experimente zur Schwindreduktion von hochfesten Betonbauteilen durch Wärmebehandlung
Authors: Stindt Jan , Forman Patrick , Mark Peter 
Published: July 2021

AbstractIm Beitrag wird die Reduktion des Schwindens von hochfestem Beton durch eine Wärmebehandlung untersucht. Betone werden wärmebehandelt, um die Erhärtung zu beschleunigen und ein frühes Ausschalen zu ermöglichen. Durch eine geeignete Wahl der maximalen Behandlungstemperatur, der Aufheiz‐ und Abkühlrate sollen Schädigungen des Betongefüges minimiert werden. Dies führt zu Wärmebehandlungsdauern von mehr als 24 h, was für eine serielle Fertigung von Betonfertigteilen zu lange ist. Für eine minimal kurze Wärmebehandlung wird auf eine Vorlagerungszeit sowie eine reglementierte Aufheizrate verzichtet, sodass das Aufheizen direkt nach dem Betonieren beginnt. Diese Verkürzung hat Einfluss auf das Schwindverhalten. Es wird hier an Prismen mit und ohne Stahlfasern sowie an Balken mit einem Stabstahlbewehrungsgrad von 1,8 % und 3,1 % untersucht. Alle Proben werden bei 80 °C und 60 % rel. Luftfeuchte für 1, 2, 4, 6 und 24 h wärmebehandelt. Proben ohne Wärmebehandlung dienen als Referenz. Die Ergebnisse zeigen, dass mit zunehmender Wärmebehandlungsdauer die Schwinddehnung deutlich reduziert wird. Sie wird zudem mit zunehmendem Bewehrungsgrad geringer. Um das Schwindverhalten in Abhängigkeit von der Wärmebehandlung zu prognostizieren, werden datenbasierte Antwortflächen abgeleitet und validiert. Dabei steigt die Vorhersagequalität mit zunehmendem Betonalter.
Sharp Phase Transition by the Enhanced Lattice Stability of Low‐Temperature Phase of Cr‐Doped VO2
Authors: Hong Seong‐Cheol , Lee Myeongsoon , Lee Myung Won , Kim Don 
Published: July 2021

We have prepared Cr‐doped VO2 film (V1−xCrxO2, 0 ≤ x ≤ 0.15) on a c‐cut sapphire plate (0001). The insulator to metal transition (IMT) behavior of the VO2 was observed by the resistance and transmittance measurements near the phase transition point (Tc ~ 340 K). Whereas the starting point of metal to insulator transition (THE) was nearly constant at 350 K (x ≤ 0.03), the starting point of the insulator to metal transition (THS) was shifted from 308 K (x = 0) to 326 K (x = 0.05), suggesting that the Cr‐doped VO2 lattice is significantly stabilized below Tc of the VO2. The difference between THS and THE and the gap between thermal cycles (hysteresis gap), which reflect the sharpness of the phase transition, were minimal at x = 0.03–0.05 in V1−xCrxO2. This sudden phase transition of Cr‐doped VO2 is expected to be uniquely advantageous for sensitive on–off applications.
Double Connective Tissue Graft to Treat Deep Coronal‐Radicular Abrasion: A 19‐Year Follow‐Up Case Report
Authors: Franceschi Debora , Prato Giovan Paolo Pini , Gianfilippo Riccardo Di 
Published: July 2021

IntroductionWhen gingival recession is combined with cervical abrasion, root coverage outcomes are less predictable due to the challenging adaptation of the connective tissue graft (CTG) to the marked root step. Removing additional tooth structure can improve soft‐tissue adaptation with the downside of a possible increase in dental hypersensitivity or pulpitis. Therefore, the aim of this report was to demonstrate a surgical technique using two grafts which does not require any further modification of the root surface, in order to successfully treat recession associated with deep cervical abrasion.Case PresentationA case of gingival recession associated with a deep root step and cemento‐enamel junction alteration (B+; abrasion depth > 1 mm) was successfully treated via a bilaminar grafting technique using two CTG layers covered by a coronally advanced flap (CAF). The tooth surface was polished and did not receive any grinding, blending, planing, or other alterations. Complete recession coverage, complete abrasion coverage, and resolution of baseline sensitivity were achieved 1 year after surgical intervention and were maintained for 19 years with further coronal displacement of the gingival margin due to creeping attachment.ConclusionsThe double CTG technique showed optimal clinical results in terms of coverage and resolution of hypersensitivity of a recession associated with a deep cervical abrasion. No additional removal of dental tissue was needed, and the clinical outcomes were stably maintained over a long‐term follow‐up.
Incidence, treatment, and outcomes of acute myocardial infarction following transcatheter or surgical aortic valve replacement
Authors: Isogai Toshiaki , Saad Anas M. , Ahuja Keerat Rai , Shekhar Shashank , Abdelfattah Omar M. , Gad Mohamed M. , Svensson Lars G. , Krishnaswamy Amar , Reed Grant W. , Puri Rishi , Tuzcu E. Murat , Ellis Stephen G. , Kapadia Samir R. 
Published: July 2021

AbstractObjectivesThis study aimed to evaluate the incidence, treatment, and outcomes of acute myocardial infarction (AMI) following transcatheter or surgical aortic valve replacement (TAVR or SAVR).BackgroundCoronary artery disease is common in patients who undergo aortic valve replacement. However, little is known about differences in clinical features of post‐TAVR or post‐SAVR AMI.MethodsWe retrospectively identified post‐TAVR or post‐SAVR (including isolated and complex SAVR) patients admitted with AMI using the Nationwide Readmissions Database 2012–2017. Incidence, invasive strategy (coronary angiography or revascularization), and in‐hospital outcomes were compared between post‐TAVR and post‐SAVR AMIs.ResultsThe incidence of 180‐day AMI was higher post‐TAVR than post‐SAVR (1.59% vs. 0.72%; p < 0.001). Post‐TAVR AMI patients (n = 1315), compared with post‐SAVR AMI patients (n = 1344), were older, had more comorbidities and more frequent non‐ST‐elevation AMI (NSTEMI: 86.6% vs. 78.0%; p < 0.001). After propensity‐score matching, there was no significant difference in in‐hospital mortality between post‐TAVR and post‐SAVR AMIs (14.7% vs. 16.1%; p = 0.531), but the mortality was high in both groups, particularly in ST‐elevation AMI (STEMI: 38.8% vs. 29.2%; p = 0.153). Invasive strategy was used less frequently for post‐TAVR AMI than post‐SAVR AMI (25.6% vs. 38.3%; p < 0.001). Invasive strategy was associated with lower mortality in both post‐TAVR (adjusted odds ratio = 0.40; 95% confidence interval = [0.24–0.66]) and post‐SAVR groups (0.60 [0.41–0.88]).ConclusionsAMI, albeit uncommon, was more frequent post‐TAVR than post‐SAVR. Patients commonly presented with NSTEMI, but the mortality of STEMI was markedly high. Further studies are needed to understand why a substantial percentage of patients do not receive invasive coronary treatment, particularly after TAVR, despite seemingly better outcomes with invasive strategy.
Urea‐Functionalized Swelling Poly(ionic liquid)s as Efficient Catalysts for the Transesterification and Hydrolysis of Ethylene Carbonate
Authors: Hu Hao , Wang Xin , Chen Bihua , Gao Guohua 
Published: July 2021

AbstractUrea‐functionalized poly(ionic liquid)s (PILs) were synthesized through polymerization of urea tethered imidazolium ionic liquid monomers (urea‐IL) with sodium acrylate, and N,N′‐methylenebisacrylamide (MBA) as a crosslinker. Close‐packed and interconnected pores (1–4
) under swollen state could be observed from the cryogenic scanning electron microscopy (cryo‐SEM) images. The promising catalytic activity of the PILs was illustrated for the transesterification reaction of ethylene carbonate with methanol. High activity and selectivity could be achieved by using poly(urea‐IL)‐n catalysts, which was similar to that of corresponding homogeneous ionic liquid catalysts. The urea tethered imidazolium in PILs acted as hydrogen‐bonding donor to activate ethylene carbonate and intermediate 2‐hydroxyethyl methyl carbonate (HEMC) for enhancing catalytic activity. The swelling ability of urea‐functionalized PILs in methanol enabled active urea sites accessible for substrates. However, the complete conversion of ethylene carbonate was limited by reversible reaction between ethylene carbonate and HEMC. A possible synergistic activation mechanism for the transesterification reaction was proposed and supported by NMR titrations. The catalyst can be reused and recycled five times with stable activity. Furthermore, urea‐functionalized swelling PILs also exhibited high catalytic activity for the hydrolysis of ethylene carbonate.
Ultralight PEDOT Functionalized Separators toward High‐Performance Lithium Metal Anodes
Authors: Yao Wei , Xu Min , Qiu Weijie , Wang Jinshan , Sun Yuxi , Xu Jianguang , Zhang Qinfang 
Published: July 2021

AbstractThe practical application of lithium‐metal batteries (LMBs) has been limited by the problems of uncontrolled lithium dendrite growth, resulting in a low Coulombic efficiency (CE) and rapid battery failure. Herein, we develop an ultralight poly(3, 4‐ethylenedioxythiophene) (PEDOT) modifying Celgard polypropylene (PP) separator with a mass loading of 0.08 mg cm2 by vapor phase polymerization. The increased affinity between the PEDOT/PP separator and electrolyte interface enables homogenous Li+ flux. Meanwhile, the lithiophilic thiophene functional groups of PEDOT guide uniform Li nucleation and growth through the formation of Li−S bond. As a result, dendrite‐free Li deposition has been achieved with a high CE of 98.0 % over 150 cycles and flat stable overpotential of ∼90 mV at an ultrahigh rate of 20 mA cm−2 in the symmetric cell. Remarkably, the Li||PEDOT/PP||LiNi0.8Co0.1Mn0.1O2 full cells demonstrate superior stability up to 500 cycles with a discharge capacity of 119 mAh g−1 at 1 C. This work paves way for modifying separator for high‐performance LMBs.
Nonlinear analysis of radio‐frequency quadrature two‐stage ring oscillators
Authors: Fekih‐Ahmed Lazhar 
Published: July 2021

AbstractWe provide a rigorous nonlinear analysis of a large class of radio‐frequency (RF) two‐stage differential ring oscillators. We show that the oscillator's behavior can be recast into the classical Hopf planar dynamical system. Relying on well‐known results for such systems, we give a thorough investigation of the oscillator behavior under noise. We also provide compact analytical expressions for all relevant design measures, offering the designer straightforward guidelines for two‐stage ring oscillators. These expressions predict amplitude, frequency, period jitter, and phase noise very accurately. The formulas are validated for three popular differential delay cells using SPICE simulations.
Grow slowly, persist, dominate—Explaining beech dominance in a primeval forest
Authors: Petrovska Roksolana , Brang Peter , Gessler Arthur , Bugmann Harald , Hobi Martina Lena 
Published: July 2021

AbstractBeing able to persist in deep shade is an important characteristic of juvenile trees, often leading to a strong dominance of shade‐tolerant species in forests with low canopy turnover and a low disturbance rate. While leaf, growth, and storage traits are known to be key components of shade tolerance, their interplay during regeneration development and their influence on juveniles' survival time remains unclear. We assessed the ontogenetic effects of these three traits on the survival time of beech (Fagus sylvatica), and Norway and sycamore maples (Acer pseudoplatanus, Acer platanoides) in a primeval beech forest. Biomass allocation, age, and content of nonstructural carbohydrates (NSC) were measured in the stems and roots of 289 seedlings and saplings in high‐ and low‐vitality classes. Saplings experienced a trade‐off between absolute growth rate (AGR) and storage (NSC) as the leaf area ratio (LAR) decreases with biomass development. High LAR but low AGR and low NSC corresponded to beech with a marked ability to persist in deep shade while awaiting canopy release. In turn, a comparably small LAR in combination with a high AGR and higher storage (NSC), as observed in Norway maple and sycamore maple, reduced sapling survival time, thus offering an explanation for beech dominance and maple disappearance in the undergrowth of old‐growth beech forests.
Quantifying lost and inaccessible habitat for Pacific salmon in Canada’s Lower Fraser River
Authors: Finn Riley J. R. , Chalifour Lia , Gergel Sarah E. , Hinch Scott G. , Scott David C. , Martin Tara G. 
Published: July 2021

AbstractLoss of connectivity caused by anthropogenic barriers is a key threat for migratory freshwater species. The anadromous life history of salmonids means that barriers on streams can decrease the amount of habitat available for spawning and rearing. To set appropriate targets for restoration, it is important to know how different populations have been impacted in terms of the location and extent of historically available habitat that has been lost or has become inaccessible. Using mapped and predicted barriers to fish passage in streams and diking infrastructure, the amount of both floodplain and linear stream habitat that remains accessible today was estimated for 14 populations of salmon in the Lower Fraser River, British Columbia, Canada’s most productive salmon river. To place these estimates within a historical context, the floodplain area was estimated using vegetation records from the 1850s, and lost streams were estimated using a digital elevation model‐derived stream network. To bolster areas where little mapping has been done, current barrier data were used to predict locations likely to have barriers. Accessibility to floodplain was poor across the entire region with only 15% of the historical floodplain remaining accessible. Linear stream habitat ranged in accessibility from 28% to 99% across populations based on mapped barriers. Inclusion of predicted barriers revealed an additional 33 km of potentially inaccessible stream habitat and the modeled stream network located approximately 1700 km of stream length that has been completely lost. Comparing habitat accessibility and barrier density against the assessed status of populations revealed insights useful for understanding the impact of barriers on spawning and rearing and guiding the allocation of restoration effort. Applying methods for addressing missing data, such as lost streams and unmapped barriers, was essential for estimating the accessibility of habitat within a historical context. While much emphasis has been placed on the role of marine conditions in wild Pacific salmon recovery, the magnitude of habitat loss in the Fraser cannot be ignored and suggests it is a major driver of observed salmon declines.
N→Ge Coordinated Germylenes as Ligands for Monomeric Cu Complexes
Authors: Vítek Dominik , Dostál Libor , Růžička Aleš , Mikysek Tomáš , Jambor Roman 
Published: July 2021

AbstractSynthesis of monomeric Cu complexes stabilized by the N→Ge coordinated germylene L(Cl)Ge (L=2‐Et2NCH2‐4,6‐tBu2‐C6H2) is reported. The reactions of the [L(Cl)Ge]2CuI (1) with AgX provided the complexes [L(Cl)Ge]2CuX (X=2: X=OAc, 3: X=OTf) by selective substitution of the CuI bond. In contrast, the reaction of 1 with K[BEt3H] provided [L(H)Ge]2CuI (4), the product of selective substitution of the GeCl bonds. The 4 represents the first example of Cu complex stabilized by two organogermaniun hydrides [L(H)Ge].
Ionic Liquids with Multi‐Active Sites Synergistically Catalyzed Metal‐Free Transformation of Alcohols Using Dimethyl Carbonate as an Environmental Solvent
Authors: Li Zengmin , Wen Yating , Wang Ning , Han Feng , Li Ying , Zhuang Hongfeng , Miao Chengxia 
Published: July 2021

AbstractOne of the ultimate goals in organic synthesis is to develop metal‐free, efficient and easily separable catalytic system for atom economic organic reactions in an environmental solvent. Direct substitution reaction of alcohols and hydrocarbon compounds is a significant and atom economic method for C−C bond formation. Herein, a metal‐free and efficient catalytic system including recyclable pyridine‐based ionic liquids with multiple active sites as the catalyst and dimethyl carbonate as the environmentally friendly solvent was developed for atom economic C3 substitution of 4‐hydroxycoumarins with alcohols. Primary aromatic alcohols, secondary aliphatic and aromatic alcohols were suitable for the reaction, providing up to 99 % yield. The catalytic system could be easily scaled up to gram‐scale with nearly quantitative yield. Coumatetralyl as commercial rodenticide could be prepared directly from commercially available 4‐hydroxycoumarin and 1,2,3,4‐tetrahydronaphthalen‐1‐ol. Racemic product derived from the reaction of (R)‐1‐phenylethanol and 4‐hydroxycoumarin indicated the reaction was achieved through an SN1 pathway. The comparison of the activities and acidities of the ionic liquids demonstrated that there was no directly relationship between them. Control experiments showed that the reaction probably proceeded via carbocation, ether intermediate and synergistically promoted effect of hydrogen bonding between the ionic liquid with multi‐active sites and substrates.