bluuebunny/crossref_metadata_2025 huggingface dataset:
All‐Printed Flexible and Stretchable Electronics with Pressing or Freezing Activatable Liquid‐Metal–Silicone Inks
Authors: Zhou Lu‐yu , Fu Jian‐zhong , Gao Qing , Zhao Peng , He Yong
Published: October 2019

Liquid‐metal (LM)‐based flexible and stretchable electronics have attracted widespread interest in wearable computing, human–machine interaction, and soft robotics. However, many current examples are one‐off prototypes, whereas future implementation requires mass production. To address this critical challenge, an integrated multimaterial 3D printing process composed of direct ink writing (DIW) of sealing silicone elastomer and special LM‐silicone (LMS) inks for manufacturing high‐performance LM‐based flexible and stretchable electronics is presented. The LMS ink is a concentrated mixture of LM microdroplets and silicone elastomer and exhibits excellent printability for DIW printing. Guided by a verified theoretical model, a printing process with high resolution and high speed can be easily implemented. Although LMS is not initially conductive, it can be activated by pressing or freezing. Activated LMS possesses good conductivity and significant electrical response to strain. Owing to LMS's unique structure, LMS‐embedded flexible electronics exhibit great damage mitigation, in that no leaking occurs even when damaged. To demonstrate the flexibility of this process in fabricating LM‐based flexible electronics, multilayer soft circuits, strain sensors, and data gloves are printed and investigated. Notably, utilizing LMS's unique activating property, some functional circuits such as one‐time pressing/freezing‐on switch can be printed without any structural design.
Metasurface‐Empowered Optical Multiplexing and Multifunction
Authors: Chen Shuqi , Liu Wenwei , Li Zhancheng , Cheng Hua , Tian Jianguo
Published: October 2019

Metasurfaces are planar photonic elements composed of subwavelength nanostructures, which can deeply interact with light and exploit new degrees of freedom (DOF) to manipulate optical fields. In the past decade, metasurfaces have drawn great interest from the scientific community due to their profound potential to arbitrarily control light. Here, recent developments of multiplexing and multifunctional metasurfaces, which enable concurrent tasks through a dramatic compact design, are reviewed. The fundamental properties, design strategies, and applications of multiplexing and multifunctional metasurfaces are then discussed. First, recent progress on angular momentum multiplexing, including its behavior under different incident conditions, is considered. Second, a detailed overview of polarization‐controlled, wavelength‐selective, angle‐selective, and reconfigurable multiplexing/multifunctional metasurfaces is provided. Then, the integrated and on‐chip design of multifunctional metasurfaces is addressed. Finally, future directions and potential applications are presented.
Are Cu2Te‐Based Compounds Excellent Thermoelectric Materials?
Authors: Zhao Kunpeng , Liu Ke , Yue Zhongmou , Wang Yancheng , Song Qingfeng , Li Jian , Guan Mengjia , Xu Qing , Qiu Pengfei , Zhu Hong , Chen Lidong , Shi Xun
Published: October 2019

Most of the state‐of‐the‐art thermoelectric (TE) materials exhibit high crystal symmetry, multiple valleys near the Fermi level, heavy constituent elements with small electronegativity differences, or complex crystal structure. Typically, such general features have been well observed in those well‐known TE materials such as Bi2X3‐, SnX‐, and PbX‐based compounds (X = S, Se, and Te). The performance is usually high in the materials with heavy constituent elements such as Te and Se, but it is low for light constituent elements such as S. However, there is a great abnormality in Cu2X‐based compounds in which Cu2Te has much lower TE figure of merit (zT) than Cu2S and Cu2Se. It is demonstrated that the Cu2Te‐based compounds are also excellent TE materials if Cu deficiency is sufficiently suppressed. By introducing Ag2Te into Cu2Te, the carrier concentration is substantially reduced to significantly improve the zT with a record‐high value of 1.8, 323% improvement over Cu2Te and outperforms any other Cu2Te‐based materials. The single parabolic band model is used to further prove that all Cu2X‐based compounds are excellent TE materials. Such finding makes Cu2X‐based compounds the only type of material composed of three sequent main group elements that all possess very high zT  s above 1.5.
Flexible Piezoelectric Acoustic Sensors and Machine Learning for Speech Processing
Authors: Jung Young Hoon , Hong Seong Kwang , Wang Hee Seung , Han Jae Hyun , Pham Trung Xuan , Park Hyunsin , Kim Junyeong , Kang Sunghun , Yoo Chang D. , Lee Keon Jae
Published: October 2019

Flexible piezoelectric acoustic sensors have been developed to generate multiple sound signals with high sensitivity, shifting the paradigm of future voice technologies. Speech recognition based on advanced acoustic sensors and optimized machine learning software will play an innovative interface for artificial intelligence (AI) services. Collaboration and novel approaches between both smart sensors and speech algorithms should be attempted to realize a hyperconnected society, which can offer personalized services such as biometric authentication, AI secretaries, and home appliances. Here, representative developments in speech recognition are reviewed in terms of flexible piezoelectric materials, self‐powered sensors, machine learning algorithms, and speaker recognition.
Glycogen as a Building Block for Advanced Biological Materials
Authors: Besford Quinn A. , Cavalieri Francesca , Caruso Frank
Published: October 2019

Biological nanoparticles found in living systems possess distinct molecular architectures and diverse functions. Glycogen is a unique biological polysaccharide nanoparticle fabricated by nature through a bottom‐up approach. The biocatalytic synthesis of glycogen has evolved over time to form a nanometer‐sized dendrimer‐like structure (20–150 nm) with a highly branched surface and a dense core. This makes glycogen markedly different from other natural linear or branched polysaccharides and particularly attractive as a platform for biomedical applications. Glycogen is inherently biodegradable, nontoxic, and can be functionalized with diverse surface and internal motifs for enhanced biofunctional properties. Recently, there has been growing interest in glycogen as a natural alternative to synthetic polymers and nanoparticles in a range of applications. Herein, the recent literature on glycogen in the material‐based sciences, including its use as a constituent in biodegradable hydrogels and fibers, drug delivery vectors, tumor targeting and penetrating nanoparticles, immunomodulators, vaccine adjuvants, and contrast agents, is reviewed. The various methods of chemical functionalization and physical assembly of glycogen nanoparticles into multicomponent nanodevices, which advance glycogen toward a functional therapeutic nanoparticle from nature and back again, are discussed in detail.
Atomically Dispersed Binary Co‐Ni Sites in Nitrogen‐Doped Hollow Carbon Nanocubes for Reversible Oxygen Reduction and Evolution
Authors: Han Xiaopeng , Ling Xiaofei , Yu Deshuang , Xie Dengyu , Li Linlin , Peng Shengjie , Zhong Cheng , Zhao Naiqin , Deng Yida , Hu Wenbin
Published: October 2019

With the inspiration of developing bifunctional electrode materials for reversible oxygen electrocatalysis, one strategy of heteroatom doping is proposed to fabricate dual metal single‐atom catalysts. However, the identification and mechanism functions of polynary single‐atom structures remain elusive. Atomically dispersed binary Co‐Ni sites embedded in N‐doped hollow carbon nanocubes (denoted as CoNi‐SAs/NC) are synthesized via proposed pyrolysis of dopamine‐coated metal‐organic frameworks. The atomically isolated bimetallic configuration in CoNi‐SAs/NC is identified by combining microscopic and spectroscopic techniques. When employing as oxygen electrocatalysts in alkaline medium, the resultant CoNi‐SAs/NC hybrid manifests outstanding catalytic performance for bifunctional oxygen reduction/evolution reactions, boosting the realistic rechargeable zinc–air batteries with high efficiency, low overpotential, and robust reversibility, superior to other counterparts and state‐of‐the‐art precious‐metal catalysts. Theoretical computations based on density functional theory demonstrate that the homogenously dispersed single atoms and the synergistic effect of neighboring Co‐Ni dual metal center can optimize the adsorption/desorption features and decrease the overall reaction barriers, eventually promoting the reversible oxygen electrocatalysis. This work not only sheds light on the controlled synthesis of atomically isolated advanced materials, but also provides deeper understanding on the structure–performance relationships of nanocatalysts with multiple active sites for various catalytic applications.
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

A 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.

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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

Vascularization 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

Herein, 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

Many 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

Significance

The 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 Methods

Baseline 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.

Results

A 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.

Conclusion

Safety 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

Guanosine‐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

Organic 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

Lamellar 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

Aculenes 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

Water‐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

In 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

Geopolymer (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

Premise

Chloroplast primers were developed for phylogenetic and comparative studies in Thalictrum (Ranunculaceae).

Methods and Results

We 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.

Conclusions

The 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

Molecular 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

We 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

A 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

The 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.
Effects of ketamine on circadian rhythm and synaptic homeostasis in patients with treatment‐resistant depression: A protocol for mechanistic studies of its rapid and sustained antidepressant actions in humans
Authors: Zhuo Chuanjun , Tian Hongjun , Li Gongying , Chen Min , Jiang Deguo , Lin Xiaodong , Xu Yong , Wang Wenqiang
Published: October 2019

Background

The breakthrough discovery has been made that a single dose of ketamine, an N‐methyl‐D‐aspartate receptor antagonist, achieves rapid and sustained (~7 days) antidepressant activity in patients with major depressive disorder (MDD). This discovery has ushered in an exciting era of research and brought new hope for patients with MDD. However, the mechanisms underlying the specific antidepressant actions of ketamine in humans remain to be elucidated.

Objectives

This study protocol was designed to test the main hypothesis that ketamine could rapidly reverse depression‐ and stress‐associated synaptic loss and deficits in resting‐state functional connectivity and that this action could be affected by circadian rhythm, in patients with treatment‐resistant depression.

Methods/Study Design

In this clinical study, adults (aged 18–65 years) with treatment‐resistant depression will be randomized to intravenous administration of placebo (control group) or ketamine (0.5 mg/kg body weight) at 11 a.m. (daytime group), or 6 p.m. (nighttime group) for 24 weeks. The primary outcome will be the change from baseline to 24 weeks in the total Montgomery‐Asberg Depression Rating Scale score. Brain imaging, sleep, and genetic studies, including functional magnetic resonance imaging, positron emission tomography, polysomnography, and genetic analyses, will be performed to examine whether and how ketamine can rapidly reverse deficits in synaptic function and to identify objective markers for the assessment of ketamine infusion therapy for treatment‐resistant depression.

Conclusions

This clinical study protocol is the first, to our knowledge, to describe the prospective testing of the hypothesis that daytime and nighttime administrations of ketamine would have different antidepressant effects. The brain imaging, sleep, and genetic findings from patients with treatment‐resistant depression are expected to shed new light on the mechanisms of ketamine and its interaction with target sites in the brain, which can be used for objective evaluation of the efficacy of ketamine.
Comparative Studies of Phytochemical Screening, HPLC‐PDA‐ESI‐MS/MS‐LC/HR‐ESI‐MS Analysis, Antioxidant Capacity andin VitroFermentation of Officinal Sage (Salvia officinalisL.) Cultivated in Different Biotopes of Northwestern Tunisia
Authors: Jedidi Saber , Selmi Houcine , Aloui Foued , Rtibi Kais , Jridi Mourad , Abbes Chaâbane , Sebai Hichem
Published: October 2019

We aimed in the present study to investigate the chemical composition, the antioxidant capacities as well as thein vitrofermentation properties ofSalvia officinalisleaves aqueous extract (SOLAE) grown in four regions of northwestern Tunisia. Our data firstly indicated a spatial variation (P<0.05) in condensed tannins, total lipids, polyphenols and flavonoids contents. The HPLC‐PDA‐ESI‐MS/MS‐LC/HR‐ESI‐MS technique allowed to the identification of 13 phenolic compounds and showed that protocatechuic acid is the major constituent of the plant leaves grown in Tabarka, Ain Draham and Testour. The SOLAE of the plant grown in Tabarka presents the most potent scavenging activity against DPPH radical and had the highest percentage of inhibition. More importantly, we found in the present study that the digestibility of dry matter andin vitrofermentation showed a significant variation between the regions and the animal species. Also, we showed a very positive correlation between antioxidant properties and phenolic compounds contents. In conclusion, we suggest that SOLAE had potential beneficial effects owing in part to its antioxidant and ROS scavenging activities. Therefore,S. officinaliscan be proposed as an additive food for animals’ nutrition and health.
HIF‐1α forms regulatory loop with YAP to coordinate hypoxia‐induced adriamycin resistance in acute myeloid leukemia cells
Authors: Zhu Bin , Pan Shaoying , Liu Juanjuan , Wang Suli , Ni Ying , Xiao Linlin , Wei Quhao , Peng You , Ding Zhiyong , Zhao Wenli
Published: October 2019

Despite the improvement in acute myeloid leukemia (AML) treatments, most patients had a poor prognosis and suffered from chemoresistance and disease relapse. Therefore, there is an urgent need for elucidation of mechanism(s) underlying drug resistance in AML. In the present study, we found that AML cells showed less susceptibility to adriamycin (ADR) in the presence of hypoxia, while inhibition of hypoxia‐inducible factor 1α (HIF‐1α) by CdCl2 can make AML cells re‐susceptibile to ADR even under hypoxia. Moreover, HIF‐1α is overexpressed and plays an important role in ADR‐resistance maintenance in resistant AML cells. We further found hypoxia or induction of HIF‐1α can significantly upregulate yes‐associated protein (YAP) expression in AML cells, and resistant cells express a high level of YAP. Finally, we found that YAP may not only enhance HIF‐1α stability but also promote HIF‐1α's activity on the target gene pyruvate kinase M2. In conclusion, our data indicate that HIF‐1α or YAP may represent a therapeutic target for overcoming resistance toward adriamycin‐based chemotherapy in AML.
Experimental and Theoretical Study of Photochemical Hydrogen Evolution Catalyzed by Paddlewheel‐Type Dirhodium Complexes with Electron Withdrawing Carboxylate Ligands
Authors: Kataoka Yusuke , Yano Natsumi , Kohara Yoshihiro , Tsuji Takeshi , Inoue Satoshi , Kawamoto Tatsuya
Published: October 2019

The photochemical hydrogen evolution capabilities of paddlewheel‐type dirhodium complexes with electron withdrawing carboxylates, [Rh2(O2CR)4(H2O)2] (R=CF3 and CCl3 for [2(H2O)2] and [3(H2O)2], respectively), were investigated and compared with that of [Rh2(O2CCH3)4(H2O)2], ([1(H2O)2]), which is the most effective hydrogen evolution catalyst (HEC) among rhodium complexes developed to date. Artificial photosynthesis (AP) systems with [2(H2O)2] or [3(H2O)2], [Ir(ppy)2(bpy)](PF6), and TEA showed highly efficient hydrogen evolution activities; the turnover numbers (TON) of hydrogen evolution per Rh by the AP systems with [2(H2O)2] and [3(H2O)2] after 12 h of photo‐irradiation were 3334 and 3138, respectively. Experimental analyses and density functional theory (DFT) calculations afforded valuable insight into the hydrogen evolution mechanism of paddlewheel‐type dirhodium complexes; (i) hydrogen evolution activities of the AP systems with [2(H2O)2] and [3(H2O)2] were slightly lower than that of the AP system with [1(H2O)2] despite one‐electron reduction potentials of [2(H2O)2] and [3(H2O)2] lie on the anode side than that of [1(H2O)2], and (ii) two different pathways exist during the early stages in the photochemical hydrogen evolution by [2(H2O)2] and [3(H2O)2]. Moreover, the relative free‐energy diagrams estimated by DFT calculations clarified the energy profiles of the mechanism including the rate‐determining steps of the hydrogen evolution by [1(H2O)2]−[3(H2O)2].
Visualizing Potential‐Induced Pitting Corrosion of Ultrathin Single‐Crystalline IrO2(110) Films on RuO2(110)/Ru(0001) under Electrochemical Water Splitting Conditions
Authors: Weber Tim , Ortmann Till , Escalera‐López Daniel , Abb Marcel J. S. , Mogwitz Boris , Cherevko Serhiy , Rohnke Marcus , Over Herbert
Published: October 2019

Sophisticated IrO2(110)‐RuO2(110)/Ru(0001) model electrodes are employed in the oxygen evolution reaction (OER) under acidic conditions. The potential‐induced pitting corrosion of such electrodes is confirmed by a variety of experimental techniques, including scanning electron microscopy (SEM), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), and operando scanning flow cell‐inductively coupled plasma mass spectrometry (SFC‐ICP‐MS). The structure of the pits is reminiscent of a cylinder (evidenced by focused ion beam scanning electron microscopy: FIB‐SEM), where the inner surface of the pits is covered by hydrous RuO2 (cyclic voltammetry, ToF‐SIMS) that is formed by electrochemical oxidation of the metallic Ru(0001) substrate. The time evolution of the corrosion process at a fixed electrode potential (1.48 V vs. SHE) is followed via cyclic voltammetry and SEM. The passivating IrO2(110) layer results in an “induction period” for the pit growth that is followed by rapid corrosion of the RuO2(110)/Ru(0001) substrate. The observed narrow and time‐independent size distribution relative to the mean size of the pits is attributed to a sluggish removal of the corrosion products by diffusion across the cracks of the pits covering IrO2 layer, leading to steady state corrosion during a total polarization time of 20 to 60 minutes.
Infrared Multiple Photon Dissociation Spectroscopy of Hydrated Cobalt Anions Doped with Carbon Dioxide CoCO2(H2O)n−, n=1–10, in the C−O Stretch Region
Authors: Barwa Erik , Ončák Milan , Pascher Tobias F. , Herburger Andreas , van der Linde Christian , Beyer Martin K.
Published: October 2019

We investigate anionic [Co,CO2,nH2O]− clusters as model systems for the electrochemical activation of CO2 by infrared multiple photon dissociation (IRMPD) spectroscopy in the range of 1250–2234 cm−1 using an FT‐ICR mass spectrometer. We show that both CO2 and H2O are activated in a significant fraction of the [Co,CO2,H2O]− clusters since it dissociates by CO loss, and the IR spectrum exhibits the characteristic C−O stretching frequency. About 25 % of the ion population can be dissociated by pumping the C−O stretching mode. With the help of quantum chemical calculations, we assign the structure of this ion as Co(CO)(OH)2−. However, calculations find Co(HCOO)(OH)− as the global minimum, which is stable against IRMPD under the conditions of our experiment. Weak features around 1590–1730 cm−1 are most likely due to higher lying isomers of the composition Co(HOCO)(OH)−. Upon additional hydration, all species [Co,CO2,nH2O]−, n≥2, undergo IRMPD through loss of H2O molecules as a relatively weakly bound messenger. The main spectral features are the C−O stretching mode of the CO ligand around 1900 cm−1, the water bending mode mixed with the antisymmetric C−O stretching mode of the HCOO− ligand around 1580–1730 cm−1, and the symmetric C−O stretching mode of the HCOO− ligand around 1300 cm−1. A weak feature above 2000 cm−1 is assigned to water combination bands. The spectral assignment clearly indicates the presence of at least two distinct isomers for n ≥2.
3D‐Printed Phenacrylate Decarboxylase Flow Reactors for the Chemoenzymatic Synthesis of 4‐Hydroxystilbene
Authors: Peng Martin , Mittmann Esther , Wenger Lukas , Hubbuch Jürgen , Engqvist Martin K. M. , Niemeyer Christof M. , Rabe Kersten S.
Published: October 2019

Continuous flow systems for chemical synthesis are becoming a major focus in organic chemistry and there is a growing interest in the integration of biocatalysts due to their high regio‐ and stereoselectivity. Methods established for 3D bioprinting enable the fast and simple production of agarose‐based modules for biocatalytic reactors if thermally stable enzymes are available. We report here on the characterization of four different cofactor‐free phenacrylate decarboxylase enzymes suitable for the production of 4‐vinylphenol and test their applicability for the encapsulation and direct 3D printing of disk‐shaped agarose‐based modules that can be used for compartmentalized flow microreactors. Using the most active and stable phenacrylate decarboxylase from Enterobacter spec. in a setup with four parallel reactors and a subsequent palladium(II) acetate‐catalysed Heck reaction, 4‐hydroxystilbene was synthesized from p‐coumaric acid with a total yield of 14.7 % on a milligram scale. We believe that, due to the convenient direct immobilization of any thermostable enzyme and straightforward tuning of the reaction sequence by stacking of modules with different catalytic activities, this simple process will facilitate the establishment and use of cascade reactions and will therefore be of great advantage for many research approaches.
Red‐Emitting Delayed Fluorescence and Room Temperature Phosphorescence from Core‐Substituted Naphthalene Diimides
Authors: Kuila Suman , Ghorai Anaranya , Samanta Pralok K. , Siram Raja B. K. , Pati Swapan K. , Narayan K. S. , George Subi J.
Published: October 2019

Unprecedented ambient triplet‐mediated emission in core‐substituted naphthalene diimide (cNDI) derivatives is unveiled via delayed fluorescence and room temperature phosphorescence. Carbazole core‐substituted cNDIs, with a donor–acceptor design, showed deep‐red triplet emission in solution processable films with high quantum yield. This study, with detailed theoretical calculations and time‐resolved emission experiments, enables new design insights into the triplet harvesting of cNDIs; an important family of molecules which has been, otherwise, extensively been investigated for its n‐type electronic character and tunable singlet fluorescence.
The reniform body: An integrative lateral protocerebral neuropil complex of Eumalacostraca identified in Stomatopoda and Brachyura
Authors: Thoen Hanne Halkinrud , Wolff Gabriella Hannah , Marshall Justin , Sayre Marcel E. , Strausfeld Nicholas James
Published: October 2019

Mantis shrimps (Stomatopoda) possess in common with other crustaceans, and with Hexapoda, specific neuroanatomical attributes of the protocerebrum, the most anterior part of the arthropod brain. These attributes include assemblages of interconnected centers called the central body complex and in the lateral protocerebra, situated in the eyestalks, paired mushroom bodies. The phenotypic homologues of these centers across Panarthropoda support the view that ancestral integrative circuits crucial to action selection and memory have persisted since the early Cambrian or late Ediacaran. However, the discovery of another prominent integrative neuropil in the stomatopod lateral protocerebrum raises the question whether it is unique to Stomatopoda or at least most developed in this lineage, which may have originated in the upper Ordovician or early Devonian. Here, we describe the neuroanatomical structure of this center, called the reniform body. Using confocal microscopy and classical silver staining, we demonstrate that the reniform body receives inputs from multiple sources, including the optic lobe's lobula. Although the mushroom body also receives projections from the lobula, it is entirely distinct from the reniform body, albeit connected to it by discrete tracts. We discuss the implications of their coexistence in Stomatopoda, the occurrence of the reniform body in another eumalacostracan lineage and what this may mean for our understanding of brain functionality in Pancrustacea.
π‐Expanded Thioxanthones—Engineering the Triplet Level of Thioxanthone Sensitizers for Lanthanide‐Based Luminescent Probes with Visible Excitation
Authors: Nybro Dansholm Charlotte , Junker Anne Kathrine R. , Nielsen Lea G. , Kofod Nicolaj , Pal Robert , Sørensen Thomas Just
Published: October 2019

Invited for this month's cover are the collaborating groups of Dr. Thomas Just Sørensen at the University of Copenhagen, Denmark and Dr. Robert Pal at Durham University, United Kingdom. The front cover shows the clouds parting for a cell imaged using a thioxanthone‐appended EuIII complex. This work shows that lanthanide luminescence can be used in optical bioimaging with microscopes equipped with the common blue laser line. Read the full text of the article at 10.1002/cplu.201900309.