bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coaching educators: Impact of a novel national faculty development program for didactic presentation skills
Authors: Jordan Jaime , Yarris Lalena M. , Dorfsman Michele L. , Wolf Stephen J. , Wagner Mary J. 
Published: June 2021

AbstractBackgroundDidactic lectures remain common in medical education. Many faculty physicians do not receive formal training on public presentations or leading instructional sessions. Coaching has emerged in medical education with the potential to positively impact skills. We sought to evaluate a novel, national faculty peer‐coaching program created to improve lecture presentation skills and foster career development.MethodsThis was a mixed‐methods study of participant and faculty perceptions after completing the Council of Residency Directors in Emergency Medicine Academy Coaching Program. Participants completed an online evaluative survey consisting of multiple choice and Likert‐type items. Program coaches participated in semistructured interviews. Descriptive statistics were reported for survey data. Thematic qualitative analysis by two independent reviewers was performed on interview data.ResultsDuring 2012 to 2017, a total of 30 participants and 11 coaches from 37 residency programs across the United States engaged in the program. Twenty‐four (80%) participants completed the survey. Eight (73%) coaches participated in semistructured interviews. Data were collected between October and December 2018. The mean ± SD numbers of national presentations participants had given before and after the coaching program were 6.92 ± 7.68 and 16.42 ± 15.43, respectively. Since their coaching, most participants (87.5%) have been invited to give a lecture at another institution. Many participants felt that the program improved their lecture evaluations, public speaking, ability to engage an audience, and professional development. Almost all (92%) would recommend the program to a colleague. The coaches perceived multiple benefits including improved skills, self‐reflection, networking, career advancement, and personal fulfillment. Suggestions for improvement included improved administrative processes, more clear expectations, increased marketing, and increased participant and coach engagement.ConclusionParticipants and coaches perceived multiple benefits from this novel, national faculty coaching program. With identification of the success, challenges, and suggestions for improvement, others may benefit as they develop coaching programs in medical education.
Stover harvest and tillage effects on corn seedling emergence
Authors: Agomoh Ikechukwu V. , Drury Craig F. , Reynolds W. Daniel , Woodley Alex , Yang Xueming , Phillips Lori A. , Rehmann Lars 
Published: June 2021

AbstractCorn (Zea mays L.) stover is an increasingly important feedstock for biofuel and bioproduct production; however, excessive harvest of corn stover from agricultural fields may affect corn seedling emergence and subsequent plant population which may reduce corn growth and yield. Field experiments were conducted over four consecutive growing seasons in southwestern Ontario to determine under continuous corn cropping system the effects of no‐tillage (NT), conventional tillage (CT), and five rates of stover harvest (0, 25, 50, 75, and 100 wt. %) on corn seedling emergence in a Harrow sandy loam and in a Brookston clay loam. Time to achieve 50% seedling emergence (t0.5), emergence rate constant (kG), and final seedling population (MG) were adequately simulated using the Gompertz function. Irrespective of stover removal rate and soil type, t0.5 was 2 d longer, and kG was 32% lower, under NT compared to CT. In Harrow sandy loam, stover removal from NT reduced t0.5 in 1 out of 4 yr. The 100% removal reduced t0.5 relative to 0, 25, 50, and 75% removal by 1.1–2.2 d in 2015. Averaged across both tillages and all removal rates, kG was greater in Harrow sandy loam than in Brookston clay loam. Stover removal rates had no effect on MG but averaged over all removal rates and soil types, MG was 9% lower for NT compared to CT in 2016. No‐tillage practice under corn production can impede seedlings emergence early in the growing season and stover removal from the field can help mitigate against this effect.
Upper extremity musculoskeletal disorders and work exposures among railroad maintenance‐of‐way workers
Authors: Landsbergis Paul , Johanning Eckardt , Stillo Marco , Jain Rahul , Davis Michelle 
Published: June 2021

AbstractBackgroundOur objective was to examine occupational risk factors for musculoskeletal disorders of the shoulders, elbows, wrists, and hands among railroad maintenance‐of‐way (MOW) workers. Little systematic research on musculoskeletal disorders has been conducted in this occupational group.MethodsIn total, 3995 active members of the Brotherhood of Maintenance of Way Employes Division (BMWED) completed a standardized survey focusing on disorders caused by hand‐transmitted vibration. We computed adjusted prevalence ratios (aPRs) using Poisson regression for shoulder, elbow, carpal tunnel syndrome, and vibration white finger musculoskeletal symptoms by work exposures, adjusted for age, region, race/ethnicity, smoking, potential second job, and spare time vehicle vibration exposure, and other work exposures.ResultsAmong active male BMWED members, we found associations between >5.2 years (vs. 0.0–0.7 years) duration of full‐time equivalent power tool use and shoulder pain (aPR = 2.01; 95% confidence interval [CI], 1.43–2.85), elbow pain (aPR = 2.88; 95% CI, 1.86–4.46), vibration white finger symptoms (aPR = 2.49; 95% CI, 1.06–5.85), hand/wrist pain (aPR = 2.40; 95% CI, 1.74–3.32), finger numbness or tingling (aPR = 1.86; 95% CI, 1.38–2.50) and self‐reported carpal tunnel syndrome diagnosis (aPR = 2.16; 95% CI, 1.24–3.77). Associations were not consistent across outcomes for the duration of non‐powered hand tool use and “repeated lifting, pushing, pulling, or bending.” Positive gradients were observed for most outcomes.ConclusionsHand‐arm vibration and some other biomechanical exposures were associated with shoulder, elbow, wrist, hand, and finger symptoms. Prevention programs should address occupational risk factors for upper extremity musculoskeletal disorders among MOW workers.
Counterion Control oft‐BuO‐Mediated Single Electron Transfer to Nitrostilbenes to ConstructN‐Hydroxyindoles or Oxindoles
Authors: Zhao Yingwei , Zhu Haoran , Sung Siyoung , Wink Donald J. , Zadrozny Joseph M. , Driver Tom G. 
Published: June 2021

Abstracttert‐Butoxide unlocks new reactivity patterns embedded in nitroarenes. Exposure of nitrostilbenes to sodium tert‐butoxide was found to produce N‐hydroxyindoles at room temperature without an additive. Changing the counterion to potassium changed the reaction outcome to yield solely oxindoles through an unprecedented dioxygen‐transfer reaction followed by a 1,2‐phenyl migration. Mechanistic experiments established that these reactions proceed via radical intermediates and suggest that counterion coordination controls whether an oxindole or N‐hydroxyindole product is formed.
High‐Performance Ladder‐Type Heteroheptacene‐Based Nonfullerene Acceptors Enabled by Asymmetric Cores with Enhanced Noncovalent Intramolecular Interactions
Authors: Tang Changquan , Ma Xiaoling , Wang Jin‐Yun , Zhang Xue , Liao Ruochuan , Ma Yunlong , Wang Peng , Wang Pengsong , Wang Tao , Zhang Fujun , Zheng Qingdong 
Published: June 2021

AbstractNonfullerene acceptors (MQ3, MQ5, MQ6) are synthesized using asymmetric and symmetric ladder‐type heteroheptacene cores with selenophene heterocycles. Although MQ3 and MQ5 are constructed with the same number of selenophene heterocycles, the heteroheptacene core of MQ5 is end‐capped with selenophene rings while that of MQ3 is flanked with thiophene rings. With the enhanced noncovalent interaction of O⋅⋅⋅Se compared to that of O⋅⋅⋅S, MQ5 shows a bathochromically shifted absorption band and greatly improved carrier transport, leading to a higher power conversion efficiency (PCE) of 15.64 % compared to MQ3, which shows a PCE of 13.51 %. Based on the asymmetric heteroheptacene core, MQ6 shows an improved carrier transport induced by the reduced π–π stacking distance, related with the increased dipole moment in comparison with the nonfullerene acceptors based on symmetric cores. MQ6 exhibits a PCE of 16.39 % with a VOC of 0.88 V, a FF of 75.66 %, and a JSC of 24.62 mA cm−2.
Selective 13C‐Labels on Repeating Glycan Oligomers to Reveal Protein Binding Epitopes through NMR: Polylactosamine Binding to Galectins
Authors: Moure María J. , Gimeno Ana , Delgado Sandra , Diercks Tammo , Boons Geert‐Jan , Jiménez‐Barbero Jesús , Ardá Ana 
Published: June 2021

AbstractA combined chemo‐enzymatic synthesis/NMR‐based methodology is presented to identify, in unambiguous manner, the distinctive binding epitope within repeating sugar oligomers when binding to protein receptors. The concept is based on the incorporation of 13C‐labels at specific monosaccharide units, selected within a repeating glycan oligomeric structure. No new chemical tags are added, and thus the chemical entity remains the same, while the presence of the 13C‐labeled monosaccharide breaks the NMR chemical shift degeneracy that occurs in the non‐labeled compound and allows the unique identification of the different components of the oligomer. The approach is demonstrated by a proof‐of‐concept study dealing with the interaction of a polylactosamine hexasaccharide with five different galectins that display distinct preferences for these entities.
Manipulations of Chiroptical Properties in Belt‐Persistent Cycloarylenes via Desymmetrization with Heteroatom Doping
Authors: Fukunaga Toshiya M. , Sawabe Chizuru , Matsuno Taisuke , Takeya Jun , Okamoto Toshihiro , Isobe Hiroyuki 
Published: June 2021

AbstractA desymmetrization strategy has been devised in the design of molecular cylinders to maximize the dissymmetry factor relevant to circularly polarized light. Although the highest dissymmetry factor of organic molecules was previously achieved with a chiral belt‐persistent cycloarylene having magnetic and electric transition dipole moments in parallel, we noticed that an unbalanced magnitude of two moments was detrimental for higher dissymmetry factors. In this study, a molecular cylinder was desymmetrized by arraying doped and undoped panels via stereoselective cross‐coupling macrocyclization. The desymmetrization succeeded in balancing two moments by reducing the electric transition moment at the global minimum but failed to maximize the dissymmetry factor. Structural studies revealed that the dissymmetry factor is sensitive to subtle structural fluctuations, while the rotatory strength is not affected. This study is important for the development of chiroptical materials.
Synergistic Catalysis by Brønsted Acid/Carbodicarbene Mimicking Frustrated Lewis Pair‐Like Reactivity
Authors: Chan Yi‐Chen , Bai Yuna , Chen Wen‐Ching , Chen Hsing‐Yin , Li Chen‐Yu , Wu Ying‐Yann , Tseng Mei‐Chun , Yap Glenn P. A. , Zhao Lili , Chen Hsuan‐Ying , Ong Tiow‐Gan 
Published: June 2021

AbstractCarbodicarbene (CDC), unique carbenic entities bearing two lone pairs of electrons are well‐known for their strong Lewis basicity. We demonstrate herein, upon introducing a weak Brønsted acid benzyl alcohol (BnOH) as a co‐modulator, CDC is remolded into a Frustrated Lewis Pair (FLP)‐like reactivity. DFT calculation and experimental evidence show BnOH loosely interacting with the binding pocket of CDC via H‐bonding and π‐π stacking. Four distinct reactions in nature were deployed to demonstrate the viability of proof‐of‐concept as synergistic FLP/Modulator (CDC/BnOH), demonstrating enhanced catalytic reactivity in cyclotrimerization of isocyanate, polymerization process for L‐lactide (LA), methyl methacrylate (MMA) and dehydrosilylation of alcohols. Importantly, the catalytic reactivity of carbodicarbene is uniquely distinct from conventional NHC which relies on only single chemical feature of nucleophilicity. This finding also provides a new spin in diversifying FLP reactivity with co‐modulator or co‐catalyst.
Photo Click Reaction of Acylsilanes with Indoles
Authors: Stuckhardt Constantin , Wissing Maren , Studer Armido 
Published: June 2021

AbstractLight‐mediated coupling of acylsilanes with indoles is reported. This photo click reaction occurs under mild conditions (415 nm) mostly in quantitative yield and provides stable silylated N,O‐acetals via light mediated siloxycarbene generation with subsequent indole‐N‐H insertion. We show that this very efficient and fully atom economic coupling process can be applied to conjugate complex systems, as documented by the clicking of carbohydrates with indole alkaloids. The method is also applicable to the conjugation of polymer chains. The linking acetal moiety can be readily cleaved and it is also shown that wavelength‐selective coupling and cleavage with acyl silanes bearing a second photoactive moiety is possible. This is documented by a successful polymerization/depolymerization sequence and by a polymer folding/unfolding process.
Photoinduced Reversible Semicrystalline‐to‐Amorphous State Transitions of Stereoregular Azopolyesters
Authors: Li Jie , Wang Meng‐Wie , Liu Ye , Ren Wei‐Min , Lu Xiao‐Bing 
Published: June 2021

AbstractWe report the synthesis of isotactic azobenzene‐based polyesters (azopolyesters) with main‐chain chirality via highly enantioselective resolution copolymerization of racemic azobenzene‐containing epoxides with cyclic anhydrides. All polyesters with trans‐azobenzene moieties were found to be semicrystalline materials with melting temperatures of 153–231 °C, while the corresponding isotactic cis‐azopolyesters were amorphous. The azobenzene groups in the copolymers exhibited reversible trans‐to‐cis and cis‐to‐trans photoisomerization upon irradiation with light. This demonstrates that the crystallinity of isotactic azopolyesters can be manipulated via photoinduced reversible isomerization. In addition, mixing isotactic trans‐polyesters with different enantiomeric configurations in a 1:1 mass ratio afforded crystalline stereocomplexes for which the crystalline behavior differed significantly from those of the component enantiomer. Also, photoinduced reversible transitions between semicrystalline and amorphous states were observed in various stereocomplexes of isotactic trans‐azopolyesters, similar to the isotactic azopolyesters themselves.
Capture and Separation of SO2 Traces in Metal–Organic Frameworks via Pre‐Synthetic Pore Environment Tailoring by Methyl Groups
Authors: Xing Shanghua , Liang Jun , Brandt Philipp , Schäfer Felix , Nuhnen Alexander , Heinen Tobias , Boldog Istvan , Möllmer Jens , Lange Marcus , Weingart Oliver , Janiak Christoph 
Published: June 2021

AbstractHerein, we report a pre‐synthetic pore environment design strategy to achieve stable methyl‐functionalized metal–organic frameworks (MOFs) for preferential SO2 binding and thus enhanced low (partial) pressure SO2 adsorption and SO2/CO2 separation. The enhanced sorption performance is for the first time attributed to an optimal pore size by increasing methyl group densities at the benzenedicarboxylate linker in [Ni2(BDC‐X)2DABCO] (BDC‐X=mono‐, di‐, and tetramethyl‐1,4‐benzenedicarboxylate/terephthalate; DABCO=1,4‐diazabicyclo[2,2,2]octane). Monte Carlo simulations and first‐principles density functional theory (DFT) calculations demonstrate the key role of methyl groups within the pore surface on the preferential SO2 affinity over the parent MOF. The SO2 separation potential by methyl‐functionalized MOFs has been validated by gas sorption isotherms, ideal adsorbed solution theory calculations, simulated and experimental breakthrough curves, and DFT calculations.
Influence of Iron Sulfide Nanoparticle Sizes in Solid‐State Batteries**
Authors: Dewald Georg F. , Liaqat Zainab , Lange Martin Alexander , Tremel Wolfgang , Zeier Wolfgang G. 
Published: June 2021

AbstractGiven the inherent performance limitations of intercalation‐based lithium‐ion batteries, solid‐state conversion batteries are promising systems for future energy storage. A high specific capacity and natural abundancy make iron disulfide (FeS2) a promising cathode‐active material. In this work, FeS2 nanoparticles were prepared solvothermally. By adjusting the synthesis conditions, samples with average particle diameters between 10 nm and 35 nm were synthesized. The electrochemical performance was evaluated in solid‐state cells with a Li‐argyrodite solid electrolyte. While the reduction of FeS2 was found to be irreversible in the initial discharge, a stable cycling of the reduced species was observed subsequently. A positive effect of smaller particle dimensions on FeS2 utilization was identified, which can be attributed to a higher interfacial contact area and shortened diffusion pathways inside the FeS2 particles. These results highlight the general importance of morphological design to exploit the promising theoretical capacity of conversion electrodes in solid‐state batteries.
Dissecting the Flash Chemistry of Electrogenerated Reactive Intermediates by Microdroplet Fusion Mass Spectrometry
Authors: Hu Jun , Wang Ting , Zhang Wen‐Jun , Hao Han , Yu Qiao , Gao Hang , Zhang Nan , Chen Yun , Xia Xing‐Hua , Chen Hong‐Yuan , Xu Jing‐Juan 
Published: June 2021

AbstractA novel mass spectrometric method for probing the flash chemistry of electrogenerated reactive intermediates was developed based on rapid collision mixing of electrosprayed microdroplets by using a theta‐glass capillary. The two individual microchannels of the theta‐glass capillary are asymmetrically or symmetrically fabricated with a carbon bipolar electrode to produce intermediates in situ. Microdroplets containing the newly formed intermediates collide with those of the invoked reactants at sub‐10 microsecond level, making it a powerful tool for exploring their ultrafast initial transformations. As a proof‐of‐concept, we present the identification of the key radical cation intermediate in the oxidative dimerization of 8‐methyl‐1,2,3,4‐tetrahydroquinoline and also the first disclosure of previously hidden nitrenium ion involved reaction pathway in the C−H/N−H cross‐coupling between N,N′‐dimethylaniline and phenothiazine.
Ultrafast Water Transport in Two‐Dimensional Channels Enabled by Spherical Polyelectrolyte Brushes with Controllable Flexibility
Authors: Dai Liheng , Xu Fang , Huang Kang , Xia Yongsheng , Wang Yixing , Qu Kai , Xin Li , Zhang Dezhu , Xiong Zhaodi , Wu Yulin , Guo Xuhong , Jin Wanqin , Xu Zhi 
Published: June 2021

AbstractFast water transport channels are crucial for water‐related membrane separation processes. However, overcoming the trade‐off between flux and selectivity is still a major challenge. To address this, we constructed spherical polyelectrolyte brush (SPB) structures with a highly hydrophilic polyelectrolyte brush layer, and introduced them into GO laminates, which increased both the flux and the separation factor. At 70 °C, the flux reached 5.23 kg m−2 h−1, and the separation factor of butanol/water increased to ≈8000, which places it among the most selective separation membranes reported to date. Interestingly, further studies demonstrated that the enhancement of water transport was not only dependent on the hydrophilicity of the polyelectrolyte chains, but also influenced by their flexibility in the solvent. Quartz crystal microbalance with dissipation and molecular dynamics simulations revealed the structure‐performance correlations between water molecule migration and the flexibility of the ordered polymer chains in the 2D confined space.
Synergistic toughening of epoxy resin byCTBNandCM‐β‐CD
Authors: Yin Xiangyun , Xie Zhipeng , Liu Qi , Yuan Xubo , Hou Xin , Zhao Jin 
Published: June 2021

AbstractCarboxymethyl‐β‐cyclodextrin (CM‐β‐CD) and carboxyl terminated liquid nitrile rubber (CTBN) were used as binary component fillers in toughening the epoxy resin (E‐54). For a single component filler system, the addition of CTBN resulted in significantly improved fracture toughness but reduction of glass transition temperature (Tg) and modulus of epoxy resin. On the other hand, the addition of CM‐β‐CD resulted in a modest increase in modulus andTg, and significant improvement in toughness. This work provides a promising route of nanocomposites with excellent toughness. Besides the mechanism of synergistic toughening in this project was explained, and the major toughening mechanisms were attributed to interfacial micro‐cracks, energy dissipation of CM‐β‐ CD. This work gives us a further understanding of the modification effect of β‐ CD.
Silver–N‐heterocyclic carbene complexes‐catalyzed multicomponent reactions: Synthesis, spectroscopic characterization, density functional theory calculations, and antibacterial study
Authors: Mnasri Aziza , Mejri Amal , Al‐Hazmy Sadeq M. , Arfaoui Youssef , Özdemir Ismail , Gürbüz Nevin , Hamdi Naceur 
Published: June 2021

AbstractNowadays, silver–N‐heterocyclic carbene (silver–NHCs) complexes are widely used in medicinal chemistry due to their low toxic nature toward humans. Due to the success of silver–NHCs in medicinal applications, interest in these compounds is rapidly increasing. Therefore, the interaction of N,N‐disubstituted benzimidazolium salts with Ag2O in dichloromethane to prepare novel Ag(I)–NHCs complexes was carried out at room temperature for 120 h in the absence of light. The obtained complexes were identified and characterized by 1H and 13C nuclear magnetic resonance, Fourier‐transform infrared, UV–Vis, and elemental analysis techniques. Then, the silver complexes were applied for three‐component coupling reactions of aldehydes, amines, and alkynes. The effect of changing the alkyl substituent on the NHCs ligand on the catalytic performance was investigated. In addition, it has been found that the complexes are antimicrobially active and show higher activity than the free ligand. The silver–carbene complexes showed antimicrobial activity against specified microorganisms with MIC values between 0.24 and 62.5 μg/ml. These results showed that the silver–NHC complexes exhibit an effective antimicrobial activity against bacterial and fungal strains. A density functional theory calculation study was performed to identify the stability of the obtained complexes. All geometries were optimized employing an effective core potential basis, such as LANL2DZ for the Ag atom and 6‐311+G(d,p) for all the other atoms in the gas phase. Electrostatic potential surfaces and LUMO–HOMO energy were computed. Transition energies and excited‐state structures were obtained from the time‐dependent density functional theory calculations.