bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereospecific Synthesis of (Z,Z)‐Isobenzofurans via Radical‐Enabled Cleavage of C(sp3)−C(sp3) and C(sp2)‐Halogen Bonds
Authors: Huang Min‐Hua , Shi Hao‐Nan , Zhu Chi‐Fan , He Chun‐Lan , Hao Wen‐Juan , Tu Shu‐Jiang , Jiang Bo 
Published: October 2019

AbstractA novel radical‐induced annulation/1,8‐halosulfonylation of β‐alkynyl ketones with haloaryl diazonium tetrafluoroborates and DABCO.bis(sulfur dioxide) was first achieved via the cleavage/recombination of C(sp3)−C(sp3) and C(sp2)‐halogen bonds, from which 47 examples of sulfone‐containing 1,3‐dimethylene‐substituted (Z,Z)‐isobenzofurans as single stereoisomers were synthesized in generally good yields. This multicomponent pathway is proposed to proceed through the in‐situ generation of arylsulfonyl radicals, followed by selective radical addition‐cyclization and ring‐opening of the cyclopropyl unit as well as C(sp2)‐halogen bond cleavage, resulting in the consecutive construction of three new chemical bonds, including C−S, C−O and C‐halogen bonds.magnified image
Transforming Endothelium with Platelet‐Rich Plasma in Engineered Microvessels
Authors: Nagao Ryan J. , Marcu Raluca , Wang Yuliang , Wang Lu , Arakawa Chris , DeForest Cole , Chen Junmei , López José A. , Zheng Ying 
Published: October 2019

AbstractVascularization remains an obstacle when engineering complex tissues for regeneration and disease modeling. Although progress has been made in recreating 3D vascular structures, challenges exist in generating a mature, functional endothelium. It is demonstrated that perfusing engineered microvessels with platelet‐rich plasma, a critical homeostatic component in vivo that is often overlooked in vitro, substantially transforms the endothelium, both maturing endothelial cells and improving functionality in 24 h. Platelets readily adhered to the exposed collagen‐I substrate through small gaps within engineered vessels without forming thrombi. The adherent platelets improve barrier function, enhance endothelial glycolysis, reduce thrombogenicity, and enrich smooth muscle cell growth surrounding the endothelium. These findings demonstrate that platelets are essential to the function of endothelium during vascular maturation and remodeling. This study sheds light on a potential strategy to engineer stable, implantable vascular networks.
Graphite as a Long‐Life Ca2+‐Intercalation Anode and its Implementation for Rocking‐Chair Type Calcium‐Ion Batteries
Authors: Richard Prabakar S. J. , Ikhe Amol Bhairuba , Park Woon Bae , Chung Kee‐Choo , Park Hwangseo , Kim Ki‐Jeong , Ahn Docheon , Kwak Joon Seop , Sohn Kee‐Sun , Pyo Myoungho 
Published: October 2019

AbstractHerein, graphite is proposed as a reliable Ca2+‐intercalation anode in tetraglyme (G4). When charged (reduced), graphite accommodates solvated Ca2+‐ions (Ca‐G4) and delivers a reversible capacity of 62 mAh g−1 that signifies the formation of a ternary intercalation compound, Ca‐G4·C72. Mass/volume changes during Ca‐G4 intercalation and the evolution of in operando X‐ray diffraction studies both suggest that Ca‐G4 intercalation results in the formation of an intermediate phase between stage‐III and stage‐II with a gallery height of 11.41 Å. Density functional theory calculations also reveal that the most stable conformation of Ca‐G4 has a planar structure with Ca2+ surrounded by G4, which eventually forms a double stack that aligns with graphene layers after intercalation. Despite large dimensional changes during charge/discharge (C/D), both rate performance and cyclic stability are excellent. Graphite retains a substantial capacity at high C/D rates (e.g., 47 mAh g−1 at 1.0 A g−1 s vs 62 mAh g−1 at 0.05 A g−1) and shows no capacity decay during as many as 2000 C/D cycles. As the first Ca2+‐shuttling calcium‐ion batteries with a graphite anode, a full‐cell is constructed by coupling with an organic cathode and its electrochemical performance is presented.
Bridging 2D and 3D culture: Probing impact of extracellular environment on fibroblast activation in layered hydrogels
Authors: Smithmyer Megan E. , Cassel Samantha E. , Kloxin April M. 
Published: October 2019

AbstractMany cell behaviors are significantly affected by cell culture geometry, though it remains unclear which geometry from two‐ to three‐dimensional (2D–3D) culture is appropriate for probing a specific cell function and mimicking native microenvironments. Toward addressing this, we established a 2.5D culture geometry, enabling initial cell spreading while reducing polarization to bridge between 2D and 3D geometries, and examined the responses of wound healing cells, human pulmonary fibroblasts, within it. To achieve this, we used engineered biomimetic hydrogels formed by photopolymerization, creating robust layered hydrogels with spread fibroblasts at the interface. We found that fibroblast responses were similar between 2D and 2.5D culture and different from 3D culture, with some underlying differences in mechanotransduction. These studies established the 2.5D cell culture geometry in conjunction with biomimetic synthetic matrices as a useful tool for investigations of fibroblast activation with relevance to the study of other cell functions and types.
Determinants of injury among older Saskatchewan farm operators: A prospective cohort study
Authors: Voaklander Donald C. , Norman Patrick , Dosman James A. , Day Andrew , Brison Robert J. , Koehncke Niels , Pickett William 
Published: October 2019

AbstractSignificanceThe agricultural industry differs from other businesses in the composition of its workforce. Often farm owner‐operators work beyond what society would expect to be a normal retirement age. Older farmers may be less receptive to behavioral changes designed to improve worksite safety and are at increased risk for experiencing a work‐related injury. We had a unique opportunity to evaluate the relative influence of specific occupational conditions and practices reported by older farm operators (age ≥55 years) on the occurrence of injury using a longitudinal approach.Materials and MethodsBaseline data were provided by eligible and consenting farm members in the first quarter of 2013. These farms were then followed longitudinally by mail surveys over 24 months to document injury experiences. For each survey, mailed questionnaires were sent to participating farms and completed by a single respondent. Cox proportional hazard models were used to determine which characteristics of the farm work environment were protective.ResultsA total of 96 farm injuries were reported by 73 of 566 farm operators. Medium (hazard ratio [HR] = 0.58; confidence interval [CI], 0.35‐0.96) or high (HR = 0.53; CI, 0.30‐0.94) worksite physical safety and high economic security (HR = 0.41; CI, 0.24‐0.71) were protective in reducing injury among older farmers.ConclusionSafety features in the physical environment and economic security are important protective factors for injury among older farmers. This supports injury prevention theory that suggests that engineering controls are superior to changes in work practices or the use of personal protective equipment in reducing injuries among older farmers.
Drawing with Iron on a Gel Containing a Supramolecular Siderophore
Authors: Xiao Songjun , Paukstelis Paul J. , Ash Richard D. , Zavalij Peter Y. , Davis Jeffery T. 
Published: October 2019

AbstractGuanosine‐5′‐hydroxamic acid (3) forms hydrogels when mixed with guanosine (1) and KCl. The 5′‐hydroxamic acid (HA) unit is pH‐responsive and also chelates Fe3+. When gels are prepared under basic conditions, the 5′‐HA groups are deprotonated and the anionic hydrogel binds cationic thiazole orange (TO), signaled by enhanced fluorescence. The HA nucleoside 3, when immobilized in the G‐quartet gel, acts as a supramolecular siderophore to form red complexes with Fe3+. We patterned the hydrogel's surface with FeCl3, by hand and by using a 3D printer. Patterns form instantly, are visible by eye, and can be erased using vitamin C. This hydrogel, combining self‐assembled G‐quartet and siderophore–Fe3+ motifs, is strong, can be molded into different shapes, and is stable on the bench or under salt water.
Excitation‐Dependent Long‐Life Luminescent Polymeric Systems under Ambient Conditions
Authors: Su Yan , Zhang Yongfeng , Wang Zhonghao , Gao Weichen , Jia Peng , Zhang Dan , Yang Chaolong , Li Youbing , Zhao Yanli 
Published: October 2019

AbstractOrganic room temperature luminescent materials present a unique phosphorescence emission with a long lifetime. However, many of these materials only emit single blue or green color in spite of external stimulation, and their color tunability is limited. Herein, we report a rational design to extend the emission color range from blue to red by controlling the doping of simple pyrene derivatives into a robust polymer matrix. The integration of these pyrene molecules into the polymer films enhances the intersystem crossing pathway, decreases the first triplet level of the system, and ensures the films show a sensitive response to excitation energy, finally yielding excitation‐dependent long‐life luminescent polymeric systems under ambient conditions. These materials were used to construct anti‐counterfeiting patterns with multicolor interconversion, presenting a promising application potential in the field of information security.
Elucidating Ultrafast Molecular Permeation through Well‐Defined 2D Nanochannels of Lamellar Membranes
Authors: Wu Xiaoli , Cui Xulin , Wu Wenjia , Wang Jingtao , Li Yifan , Jiang Zhongyi 
Published: October 2019

AbstractLamellar membranes with well‐defined 2D nanochannels show fast, selective permeation, but the underlying molecular transport mechanism is unexplored. Now, regular robust MXene Ti3C2Tx lamellar membranes are prepared, and the size and wettability of nanochannels are manipulated by chemically grafted hydrophilic (−NH2) or hydrophobic (−C6H5, −C12H25) groups. These nanochannels have a sharp difference in mass transfer behavior. Hydrophilic nanochannels, in which polar molecules form orderly aligned aggregates along channel walls, impart ultrahigh permeance (>3000 L m−2 h−1 bar−1), which is more than three times higher than that in hydrophobic nanochannels with disordered molecular configuration. In contrast, nonpolar molecules with disordered configuration in both hydrophilic and hydrophobic nanochannels have comparable permeance. Two phenomenological transport models correlate the permeance with the mass transport mechanism of molecules that display ordered and disordered configuration.
The Biosynthesis of Norsesquiterpene Aculenes Requires Three Cytochrome P450 Enzymes to Catalyze a Stepwise Demethylation Process
Authors: Lee Chi‐Fang , Chen Li‐Xun , Chiang Chen‐Yu , Lai Chen‐Yu , Lin Hsiao‐Ching 
Published: October 2019

AbstractAculenes are a unique class of norsequiterpenes (C14) that are produced by Aspergillus aculeatus. The nordaucane skeleton in aculenes A–D may be derived from an ent‐daucane precursor through demethylation, however, the enzymes involved remain unexplored. We identified the biosynthetic gene cluster and characterized the biosynthetic pathway based on gene inactivation, feeding experiments, and heterologous reconstitution in Saccharomyces cerevisiae and Aspergillus oryzae. We discovered that three cytochrome P450 monoxygenases are required to catalyze the stepwise demethylation process. AneF converts the 12‐methyl group into a carboxylic acid and AneD installs the 10‐hydroxy group for later tautomerization and stabilization. Finally, AneG installs an electron‐withdrawing carbonyl group at the C‐2 position, which triggers C‐12 decarboxylation to yield the nordaucane skeleton. Additionally, a terpene cyclase (AneC) was found that forms a new product (dauca‐4,7‐diene).
Efficient BiVO4 Photoanodes by Postsynthetic Treatment: Remarkable Improvements in Photoelectrochemical Performance from Facile Borate Modification
Authors: Meng Qijun , Zhang Biaobiao , Fan Lizhou , Liu Haidong , Valvo Mario , Edström Kristina , Cuartero Maria , de Marco Roland , Crespo Gaston A. , Sun Licheng 
Published: October 2019

AbstractWater‐splitting photoanodes based on semiconductor materials typically require a dopant in the structure and co‐catalysts on the surface to overcome the problems of charge recombination and high catalytic barrier. Unlike these conventional strategies, a simple treatment is reported that involves soaking a sample of pristine BiVO4 in a borate buffer solution. This modifies the catalytic local environment of BiVO4 by the introduction of a borate moiety at the molecular level. The self‐anchored borate plays the role of a passivator in reducing the surface charge recombination as well as that of a ligand in modifying the catalytic site to facilitate faster water oxidation. The modified BiVO4 photoanode, without typical doping or catalyst modification, achieved a photocurrent density of 3.5 mA cm−2 at 1.23 V and a cathodically shifted onset potential of 250 mV. This work provides an extremely simple method to improve the intrinsic photoelectrochemical performance of BiVO4 photoanodes.
Quantification of the Young's modulus for polypropylene: Influence of initial crystallinity and service temperature
Authors: Li Jiquan , Zhu Zhou , Li Taidong , Peng Xiang , Jiang Shaofei , Turng Lih‐Sheng 
Published: October 2019

ABSTRACTIn this study, the mechanical properties of isotactic polypropylene (iPP) materials with different crystallinities at room and elevated temperatures were investigated. In order to obtain samples with a certain range of crystallinity, and to ensure a uniform microstructure of these samples, the iPP samples obtained by injection molding required melt compression molding and controlled annealing. In the macromechanical studies, the experimental results showed that the storage modulus and Young's modulus of polypropylene were sensitive to the service temperature. The crystallinity also had a great influence on this relationship. A function was proposed to evaluate the dependence of the Young's modulus of polypropylene on initial crystallinity and service temperature, and tested based on experimental data. The Young's modulus of iPP is reduced by about 90% when the service temperature rises from 25 to 125 °C. Moreover, the reduced value in Young's modulus between polypropylene having the highest and lowest crystallinity was reduced from 214.55 to 56.75 MPa. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48581.
Role of geopolymer as a cure activator in sulfur vulcanization of epoxidized natural rubber
Authors: Yangthong Hassarutai , Pichaiyut Skulrat , Wisunthorn Suwaluk , Kummerlöwe Claudia , Vennemann Norbert , Nakason Charoen 
Published: October 2019

ABSTRACTGeopolymer (GP) was synthesized and used as activators in sulfur vulcanization of epoxidized natural rubber (ENR). Influences of GP on cure characteristics, crosslink density, mechanical, thermal, and morphological properties were investigated and compared to the conventional rubber formulation with ZnO activator. The ZnO is a hazardous chemical for the environment and has proclaimed that its application in rubber technology should be reduced and controlled. It was found that the GP‐activated ENR compounds showed significantly higher vulcanization rate than cases with the conventional ZnO compound. This was indicated by the GP activated compounds having shorter scorch time, cure times, and lower activation energy but higher cure rate index (CRI). Also, the GP activated ENR compounded with stearic acid exhibited the highest conversion. This matches well the highest torque difference and crosslink density, observed by temperature scanning stress relaxation (TSSR) and swelling measurements. Furthermore, the GP‐activated vulcanizate had better thermal stability than the ZnO‐activated ENR material. In addition, the GP‐activated ENR vulcanizate with stearic acid exhibited high 100% moduli, tensile strength, and hardness. This proves that GP has a high potential for use as activators in sulfur vulcanization of rubber compounds, as an alternative to the conventional ZnO. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48624.
Chloroplast primers for clade‐wide phylogenetic studies of Thalictrum
Authors: Morales‐Briones Diego F. , Arias Tatiana , Di Stilio Verónica S. , Tank David C. 
Published: October 2019

PremiseChloroplast primers were developed for phylogenetic and comparative studies in Thalictrum (Ranunculaceae).Methods and ResultsWe assembled and annotated the complete plastome sequence of T. thalictroides by combining multiple whole genome sequencing libraries. Using transcriptome‐sequencing libraries, we also assembled a partial plastome of the related species T. hernandezii. From the newly assembled plastomes and one previously sequenced plastome, we designed and validated 28 primer pairs to target variable portions of the chloroplast genome in Thalictrum. Furthermore, we tested the validated primers in 62 species of Thalictrum. The total alignment length of the 28 regions was 15,268 bp with 2443 variable sites and 92% character occupancy.ConclusionsThe newly developed chloroplast primer pairs improve the phylogenetic resolution (bootstrap support and tree certainty) in Thalictum and will be a useful resource for future phylogenetic and evolutionary studies for species in the genus and in close relatives in Thalictroideae.
A Strongly Fluorescent Molecular Material Responsive to Physical/Chemical Stimuli and their Coupled Impact
Authors: Sudhakar Pagidi , Radhakrishnan T. P. 
Published: October 2019

AbstractMolecular materials with weak but extended and pliable supramolecular interactions are versatile candidates for eliciting stimuli‐sensitive optical responses. A novel diaminodicyanoquinodimethane (DADQ) molecule, 7,7‐bis(2‐(2‐pyridyl)ethylamino)‐8,8‐dicyanoquinodimethane (BPEDQ), has been synthesized and structurally characterized; it exhibits enhanced fluorescence emission in the aggregated and solid states, characteristic of DADQs. The pyridine moieties in the molecule, in addition to the amino and cyano groups of the strongly dipolar fluorophore moiety, induce extensive H‐bonding interactions which can impart structural integrity to the solid material; this enables reversible crystalline‐amorphous transformations triggered by mechanical grinding and solvent fuming. The concomitant fluorescence color and intensity switching are prominent and reversible. Protonation‐deprotonation events induced by acidic and basic vapors also produce stark fluorescence response variations; the chemical stimuli also lead to amorphization of the solid. The full cycle of chemical and physical stimuli, and the consequence of their individual and coupled impact on the fluorescence emission, are illustrated using a BPEDQ‐doped polymer thin film.
Zn‐ and Cd‐based Coordination Polymers Offering H‐Bonding Cavities: Highly Selective Sensing of S2O72− and Fe3+ Ions
Authors: Kumar Gulshan , Pachisia Sanya , Kumar Pramod , Kumar Vijay , Gupta Rajeev 
Published: October 2019

AbstractWe present two ZnII‐ and CdII‐based coordination polymers (CPs), L‐Zn and L‐Cd, offering H‐bonding‐based cavities of varying dimensions. Both CPs were used for the highly selective detection of S2O72− and Fe3+ ions where H‐bonding based cavities played an important role. Fluorescence quenching, competitive binding studies and binding parameters substantiated significant recognition of S2O72− and Fe3+ ions by both CPs.
Tunable Electronic Memory Performances Based on Poly(Triphenylamine) and Its Metal Complex via a SuFEx Click Reaction
Authors: Xia Chenyu , Liu Cheng , Zhou Feng , Gu Peiyang , Li Hua , He Jinghui , Li Youyong , Xu Qingfeng , Lu Jianmei 
Published: October 2019

AbstractA triphenylamine derivative decorated with an azobenzene group (TDA) was synthesized via a SuFEx click reaction and its polymer, poly(triphenylamine) (PTDA), was polymerized through a redox polymerization. More interestingly, its polymeric metal complex, PTDA‐Fe, can be simply obtained via one‐pot reaction between TDA and FeCl3 owing to TDA showing a strong affinity to the FeIII ion. The sandwich memory device based on PTDA nanofilms as active layers exhibited a binary memory performance. However, the memory device based on its polymeric metal complex exhibited a unique ternary memory behavior. The different memory performances should come from the different conductive mechanism. The mechanism of such ternary memory devices is illustrated based on both the theoretical calculation and experiments. Our work provides new insights into the preparation of novel materials for multilevel memory devices.
Nrf2‐modulation by seleno‐hormetic agents and its potential for radiation protection
Authors: Bartolini Desirée , Tew Kenneth D. , Marinelli Rita , Galli Francesco , Wang Gavin Y. 
Published: October 2019

AbstractThe trace element selenium (Se) is an essential component of selenoproteins and plays a critical role in redox signaling via regulating the activity of selenoenzymes such as thioredoxin reductase‐1 and glutathione peroxidases. Se compounds and its metabolites possess a wide range of biological functions including anticancer and cytoprotection effects, modulation of hormetic genes and antioxidant enzyme activities. Radiation‐induced injury of normal tissues is a significant side effect for cancer patients who receive radiotherapy in the clinic and the development of new and effective radioprotectors is an important goal of research. Others and we have shown that seleno‐compounds have the potential to protect ionizing radiation‐induced toxicities in various tissues and cells both in in vitro and in vivo studies. In this review, we discuss the potential utilization of Se compounds with redox‐dependent hormetic activity as novel radio‐protective agents to alleviate radiation toxicity. The cellular and molecular mechanisms underlying the radioprotection effects of these seleno‐hormetic agents are also discussed. These include Nrf2 transcription factor modulation and the consequent upregulation of the adaptive stress response to IR in bone marrow stem cells and hematopoietic precursors.