bluuebunny/crossref_metadata_2025 huggingface dataset:
Underwater Anisotropic 3D Superoleophobic Tracks Applied for the Directional Movement of Oil Droplets and the Microdroplets Reaction
Authors: Cheng Yang , Yang Qing , Fang Yao , Yong Jiale , Chen Feng , Hou Xun
Published: April 2019

In this paper, a simple way to fabricate underwater anisotropic superoleophobic tracks is reported for manipulating underwater oil droplets by the femtosecond laser etching and the oxygen plasma treatment. Laser ablation is able to generate micro/nanoscale hierarchical structures on the poly(dimethylsiloxane) (PDMS) surface. The textured PDMS surface is further turned from superhydrophobicity to hydrophilicity and underwater superoleophobicity by subsequent oxygen plasma irradiation. Underwater anisotropic 3D superoleophobic tracks can also be fabricated on the PDMS surface by the laser etching method. The width of the tracks depends on the laser‐treated area, while the depth of the tracks increases with increasing the laser power and the scanning number and with decreasing the laser scanning speed/space. The underwater superoleophobic 3D tracks show ultralow adhesion and anisotropic sliding property to oil droplets, thereby allow the underwater oil droplets to move just along the track. A microdroplets reaction is proposed based on the underwater superoleophobic tracks. There is no loss of the reactants during the whole reaction process. The anisotropic sliding property of underwater organic droplets will potentially have enormous applications in droplet manipulation, microfluidics system, surface lab‐chip devices, and chemical engineering.
2D Diluted Multiferroic Semiconductors upon Intercalation
Authors: Tu Zhengyuan , Wu Menghao
Published: April 2019

The direct combination of high‐mobility semiconductors and efficient multiferroic memories within the same material is desirable for integration of multifunctional electronics but remains a challenge. Stimulated by recent progress on intercalation of layered materials, first‐principles evidence of 2D room‐temperature multiferroicity in a series of doped metal dichalcogenides is shown, mainly focused on intercalated MoS2 and Bi2Se3. The intercalated ions may induce a switchable vertical polarization for high‐density recording as well as electrically tunable magnetism for highly efficient “electric writing + magnetic reading.” Akin to diluted magnetic semiconductors, certain multiferroic regions can be selectively formed via such doping, which can be directly integrated in the high‐mobility semiconductor wafer like n/p doping channels. In particular, other intriguing properties such as topological superconductivity may also be endowed in ferroelectric metal CuxBi2Se3. The bandgap of the intercalated systems can also be tuned via control of the doping density of ions, which may render a spatial‐varying bandgap for efficient light adsorption plus the enhanced exciton separation and open‐circuit voltage for ferroelectric photovoltaics.
Ruthenium‐Based Single‐Atom Alloy with High Electrocatalytic Activity for Hydrogen Evolution
Authors: Chen Cui‐Hong , Wu Deyao , Li Zhe , Zhang Rui , Kuai Chun‐Guang , Zhao Xue‐Ru , Dong Cun‐Ku , Qiao Shi‐Zhang , Liu Hui , Du Xi‐Wen
Published: April 2019

Highly efficient and stable catalysts for the hydrogen evolution reaction, especially in alkaline conditions are crucial for the practical demands of electrochemical water splitting. Here, the synthesis of a novel RuAu single‐atom alloy (SAA) by laser ablation in liquid is reported. The SAA exhibits a high stability and a low overpotential, 24 mV@10 mA cm−2, which is much lower than that of a Pt/C catalyst (46 mV) in alkaline media. Moreover, the turnover frequency of RuAu SAA is three times that of Pt/C catalyst. Density functional theory computation indicates the excellent catalytic activity of RuAu SAAs originates from the relay catalysis of Ru and Au active sites. This work opens a new avenue toward high‐performance SAAs via fast quenching of immiscible metals.
Evidencing Excellent Thermal‐ and Photostability for Single‐Component Organic Solar Cells with Inherently Built‐In Microstructure
Authors: He Yakun , Heumüller Thomas , Lai Wenbin , Feng Guitao , Classen Andrej , Du Xiaoyan , Liu Chao , Li Weiwei , Li Ning , Brabec Christoph J.
Published: April 2019

Solution‐processed organic solar cells (OSCs) are promising low‐cost, flexible, portable renewable sources for future energy supply. The state‐of‐the‐art OSCs are typically fabricated from a bulk‐heterojunction (BHJ) active layer containing well‐mixed donor and acceptor molecules in the nanometer regime. However, BHJ solar cells suffer from stability problems caused by the severe morphological changes upon thermal or illumination stress. In comparison, single‐component organic solar cells (SCOSCs) based on a double‐cable conjugated polymer with a covalently stabilized microstructure is suggested to be a key strategy for superior long‐term stability. Here, the thermal‐ and photostability of SCOSCs based on a model double‐cable polymer is systematically investigated. It is encouraging to find that under 90 °C & 1 sun illumination, the performance of SCOSCs remains substantially stable. Transport measurements show that charge generation and recombination (lifetime and recombination order) hardly change during the aging process. Particularly, the SCOSCs exhibit ultrahigh long‐term thermal stability with 100% PCE remaining after heating at temperature up to 160 °C for over 400 h, indicating an excellent candidate for extremely rugged applications.
Ambient‐Pressure Relithiation of Degraded LixNi0.5Co0.2Mn0.3O2 (0 < x < 1) via Eutectic Solutions for Direct Regeneration of Lithium‐Ion Battery Cathodes
Authors: Shi Yang , Zhang Minghao , Meng Ying Shirley , Chen Zheng
Published: April 2019

With the rapid growth of the lithium‐ion battery (LIBs) market, recycling and re‐use of end‐of‐life LIBs to reclaim lithium (Li) and transition metal (TM) resources (e.g., Co, Ni), as well as eliminating pollution from disposal of waste batteries, has become an urgent task. Here, for the first time the ambient‐pressure relithiation of degraded LiNi0.5Co0.2Mn0.3O2 (NCM523) cathodes via eutectic Li+ molten‐salt solutions is successfully demonstrated. Combining such a low‐temperature relithiation process with a well‐designed thermal annealing step, NCM523 cathode particles with significant Li loss (≈40%) and capacity degradation (≈50%) can be successfully regenerated to achieve their original composition and crystal structures, leading to effective recovery of their capacity, cycling stability, and rate capability to the levels of the pristine materials. Advanced characterization tools including atomic resolution electron microscopy imaging and electron energy loss spectroscopy are combined to demonstrate that NCM523's original layered crystal structure is recovered. For the first time, it is shown that layer‐to‐rock salt phase change on the surfaces and subsurfaces of the cathode materials can be reversed if lithium can be incorporated back to the material. The result suggests the great promise of using eutectic Li+ molten–salt solutions for ambient‐pressure relithiation to recycle and remanufacture degraded LIB cathode materials.
Unraveling the Potassium Storage Mechanism in Graphite Foam
Authors: Liu Jilei , Yin Tingting , Tian Bingbing , Zhang Bowei , Qian Cheng , Wang Zhiqiang , Zhang Lili , Liang Pei , Chen Zhen , Yan Jiaxu , Fan Xiaofeng , Lin Jianyi , Chen Xiaohua , Huang Yizhong , Loh Kian Ping , Shen Ze Xiang
Published: April 2019

Potassium‐intercalated graphite intercalation compounds (K‐GICs) are of particular physical and chemical interest due to their versatile structures and fascinating properties. Fundamental insights into the K+ storage mechanism, and the complex kinetics/thermodynamics that control the reactions and structural rearrangements allow manipulating K‐GICs with desired functionalities. Here operando studies including in situ Raman mapping and in situ X‐ray diffraction (XRD) characterizations, in combination with density‐functional theory simulations are carried out to correlate the real‐time electrochemical K+ intercalation/deintercalation process with structure/component evolution. The experimental results, together with theoretical calculations, reveal the reversible K‐GICs staging transition: C ↔ stage 5 (KC60) ↔ stage 4 (KC48) ↔ stage 3 (KC36) ↔ stage 2 (KC24/KC16) ↔ stage 1 (KC8). Moreover, the staging transition is clearly visualized and an intermediate phase of stage 2 with the stoichiometric formula of KC16 is identified. The staging transition mechanism involving both intrastage transition from KC24 (stage 2) to KC16 (stage 2) and interstage transition is proposed. The present study promotes better fundamental understanding of K+ storage behavior in graphite, develops a nondestructive technological basis for accurately capture nonuniformity in electrode phase evolution across the length scale of graphite domains, and offers guidance for efficient research in other GICs.
Revealing the Short‐Circuiting Mechanism of Garnet‐Based Solid‐State Electrolyte
Authors: Song Yongli , Yang Luyi , Zhao Wenguang , Wang Zijian , Zhao Yan , Wang Ziqi , Zhao Qinghe , Liu Hao , Pan Feng
Published: April 2019

Garnet‐type solid‐state electrolytes (SSEs) have been widely studied as a promising candidate for Li metal batteries. Despite the common belief that inorganic SSEs can prevent dendrite propagation, garnet SSEs suffer from relatively low critical current density (CCD) at which the SSEs are abruptly short‐circuited by Li dendrites. In this study, the short‐circuiting mechanism of garnet Li7La2.75Ca0.25Zr1.75Nb0.25O12 (LLCZN) is investigated. It is found that instead of propagating uniaxially from one electrode to other in a dendritic form, metallic lithium is formed within the SSE. This can be attributed to the fact that electrons combine with Li ions at the grain boundary, which exhibits relatively high electronic conductivity, and then reduce Li+ to Li0 to cause short circuits. In order to reduce the electronic conductivity at the grain boundary, a thin layer of LiAlO2 is coated on the grain surface of LLCZN, which results in an improved CCD value. It is also found that under higher external voltages, the electronic conductivity of SSE becomes more significant, which is believed to be the origin of CCD. These findings not only shed light on the short‐circuiting mechanism of garnet‐type SSEs but also offer a novel perspective and useful guidance on their designs and modifications.
Species characteristics affect local extinctions
Authors: Zettlemoyer Meredith A. , McKenna Duane D. , Lau Jennifer A.
Published: April 2019

Premise of the Study

Human activities threaten thousands of species with extinction. However, it remains difficult to predict extinction risk for many vulnerable species. Species traits, species characteristics such as rarity or habitat use, and phylogenetic patterns are associated with responses to anthropogenic environmental change and may help predict likelihood of extinction.

Methods

We used historical botanical data from Kalamazoo County, Michigan,USA, to examine whether species traits (growth form, life history, nitrogen‐fixation, photosynthetic pathway), species characteristics (community association, species origin, range edge, habitat specialization, rarity), or phylogenetic relatedness explain local species loss at the county level.

Key Results

Across Kalamazoo County, prairie species, species at the edge of their native range, regionally rare species, and habitat specialists were most likely to become locally extinct. Prairie species experienced the highest local extinction rates of any habitat type, and among prairie species, regionally rare and specialist species were most vulnerable to loss. We found no evidence for a phylogenetic pattern in plant extinctions.

Conclusions

Our study illustrates the value of historical datasets for understanding and potentially predicting biodiversity loss. Not surprisingly, rare, specialist species occupying threatened habitats are most at risk of local extinction. As a result, identifying mechanisms to conserve or restore rare or declining species and preventing further habitat destruction may be the most effective strategies for reducing future extinction.
Synthetic copolymer (AM/AMPS/DMDAAC/SSS) as rheology modifier and fluid loss additive at HTHP for water‐based drilling fluids
Authors: Huang Yuming , Zhang Dingyu , Zheng Wenlong
Published: April 2019

In the petroleum industry, high temperature and high pressure (HTHP) would dramatically worsen rheological properties and increase fluid loss volumes of drilling fluids. Synthetic polymer as an indispensable additive has attracted more and more attention recently. In this article, a new copolymer (named AADS) of 2‐acrylamide‐2‐methylpropanesulfonic acid, acrylamide, dimethyl diallyl ammonium chloride, and sodium styrene sulfonate was synthesized through aqueous solution polymerization. The chemical structure of the copolymer was characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance. Moreover, its thermal stability was simultaneously analyzed using a differential scanning calorimetry. The results showed that the synthetic polymer contained all the designed functional groups, and its structure was consistent to the desired one. Under contamination of sodium chloride, AADS solution maintained relatively high viscosity in high concentration brine, showing a good antisalt capacity. Furthermore, the effect of AADS content and temperature on rheological behavior and fluid loss volume of the water‐based drilling fluid (WBDF) containing the synthesized product were investigated according to the American Petroleum Institute standard. Results showed that the rheological and filtration properties of the prepared WBDF were improved with the increase in the AADS concentration before and after the thermal aging test. In addition, in the temperature range of 80–240 °C, a reversible rheological behavior was observed during the heating–cooling process, and the HTHP fluid loss was controlled within 22.5 mL, suggesting that the copolymer AADS was suitable for making WBDF s with high temperature resistance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47813.
Aggregation‐Induced Emission‐Active 1,4‐Dihydropyridine‐Based Dual‐Phase Fluorescent Sensor with Multiple Functions
Authors: Zhou Yibin , Chen Yating , Duan Chong , Zeng Lintao , Liu Miaochang , Zhou Yunbing , Gao Wenxia , Huang Xiaobo , Wu Huayue
Published: April 2019

A N‐2‐phenylethyl‐substituted 1,4‐dihydropyridine derivative (NDHP) containing 5,5‐dimethylcyclohexane‐1,3‐dione and naphthylethylene was designed and synthesized. NDHP acts as a multifunctional fluorescent sensor in dual phases. The crystal structure analysis confirms that the NDHP molecules have highly twisted conformations. The twisted conformation results in aggregation‐induced emission properties and solid‐state emission, by restricting the intramolecular free rotation in the aggregated or solid state. In the solid state, NDHP exhibits reversible mechanochromic properties as a result of the transition between the amorphous and crystalline states. NDHP also exhibits a rare phenomenon of acid‐fumed solid‐state emission enhancement owing to the change in packing mode from a zigzag arrangement to J‐aggregation. The solid‐state stimuli‐responsive fluorescence switching is applied to realize a rewritable optical recording media and a multiple output combinational logic system. In solution, NDHP shows a selective fluorescence response for environmentally harmful Hg2+, with a limit of detection of 2.7 nm. This results from the “turn‐on” responsive behavior owing to the Hg2+‐triggered aggregation of the NDHP molecules. NDHP is also used in the imaging of intracellular Hg2+ in HeLa cells. These findings provide a feasible and attractive route for developing multifunctional fluorescent sensors for use in dual phases.
How stars and planets interact: A look through the high‐energy window
Authors: Poppenhaeger Katja
Published: April 2019

The architecture of exoplanetary systems is often different from the solar system, with some exoplanets being in close orbits around their host stars and having orbital periods of only a few days. In analogy to interactions between stars in close binary systems, one may expect interactions between the star and the exoplanet as well. From theoretical considerations, effects on the host star through tidal and magnetic interaction with the exoplanet are possible; for the exoplanet, some interesting implications are the evaporation of the planetary atmosphere and potential effects on the planetary magnetism. In this review, several possible interaction pathways and their observational prospects and existing evidence are discussed. A particular emphasis is put on observational opportunities for these kinds of effects in the high‐energy regime.
3D Primary Hepatocyte Culture Systems for Analyses of Liver Diseases, Drug Metabolism, and Toxicity: Emerging Culture Paradigms and Applications
Authors: Lauschke Volker M. , Shafagh Reza Z. , Hendriks Delilah F. G. , Ingelman‐Sundberg Magnus
Published: April 2019

Recent research has shown that the maintenance of relevant liver functions ex vivo requires models in which the cells exhibit an in vivo‐like phenotype, often achieved by reconstitution of appropriate cellular interactions. Multiple different models have been presented that differ in the cells utilized, media, and culture conditions. Furthermore, several technologically different approaches have been presented including bioreactors, chips, and plate‐based systems in fluidic or static media constituting of chemically diverse materials. Using such models, the ability to predict drug metabolism, drug toxicity, and liver functionality have increased tremendously as compared to conventional in vitro models in which cells are cultured as 2D monolayers. Here, the authors highlight important considerations for microphysiological systems for primary hepatocyte culture, review current culture paradigms, and discuss their opportunities for studies of drug metabolism, hepatotoxicity, liver biology, and disease.
Disruption of sleep architecture in Prevotella enterotype of patients with obstructive sleep apnea‐hypopnea syndrome
Authors: Ko Chih‐Yuan , Fan Ji‐Mim , Hu An‐Ke , Su Huan‐Zhang , Yang Jiao‐Hong , Huang Li‐Mei , Yan Fu‐Rong , Zhang Hua‐Ping , Zeng Yi‐Ming
Published: April 2019

Introduction

Intermittent hypoxia and sleep fragmentation are critical pathophysiological processes involved in obstructive sleep apnea‐hypopnea syndrome (OSAHS). Those manifestations independently affect similar brain regions and contribute to OSAHS‐related comorbidities that are known to be related to the host gut alteration microbiota. We hypothesized that gut microbiota disruption may cross talk the brain function via the microbiota–gut–brain axis. Thus, we aim to survey enterotypes and polysomnographic data of patients with OSAHS.

Methods

Subjects were diagnosed by polysomnography, from whom fecal samples were obtained and analyzed for the microbiome composition by variable regions 3–4 of 16S rRNA pyrosequencing and bioinformatic analyses. We examined the fasting levels of interleukin‐6 and tumor necrosis factor‐alpha of all subjects.

Results

Three enterotypes Bacteroides, Ruminococcus, and Prevotella were identified in patients with OSAHS. Arousal‐related parameters or sleep stages are significantly disrupted in apnea‐hypopnea index (AHI) ≥15 patients with Prevotella enterotype; further analysis this enterotype subjects, obstructive, central, and mixed apnea indices, and mean heart rate are also significantly elevated in AHI ≥15 patients. However, blood cytokines levels of all subjects were not significantly different.

Conclusions

This study indicates the possibility of pathophysiological interplay between enterotypes and sleeps structure disruption in sleep apnea through a microbiota–gut–brain axis and offers some new insight toward the pathogenesis of OSAHS.
Mainstreaming public–private partnership in national development: How ready is Ghana?
Authors: Ahenkan Albert
Published: April 2019

Public–private partnership (PPP) is a relatively new development paradigm in most developing countries. In an increasingly competitive global environment, governments around the world are focusing on new ways to finance development projects, build infrastructure, and provide social services to their citizens. This paper examines the challenges and the enabling environment for PPP mainstreaming in Ghana's development agenda. The study reviewed critical literature pertaining to prospects and challenges of PPPs across the world and critical success factors and challenges. The study was spiced by data generated through in‐depth interviews with experts on PPPs in Ghana. The paper reveals that implementation of PPPs in Ghana could be fraught with a number of challenges including regulatory frameworks, weak institutions, weak technical expertise, political will, bureaucracy, poor maintenance culture, contracting, negotiation challenges, and risk sharing and corruption. These challenges are complex in nature and require concerted effort and enabling environment to address them. There is the need for a clear regulatory framework and institutional capacity building to enable Ministries, Departments and Agencies and Metropolitan, Municipal and District Assemblies to effectively handle the PPP processes in Ghana.
TLR4 increases the stemness and is highly expressed in relapsed human hepatocellular carcinoma
Authors: Zhou Shuang , Du Renle , Wang Zhenglu , Shen Wenzhi , Gao Ruifang , Jiang Shan , Fang Yan , Shi Yuzhi , Chang Antao , Liu Lei , Liu Chenghu , Li Na , Xiang Rong
Published: April 2019

Toll‐like receptor 4 (TLR4) plays an essential role in cancer progress. Here, we find that the expression of TLR4 in relapsed human hepatocellular carcinoma (HCC) clinical samples is higher than that in the non‐relapsed ones, which leads us to explore the role of TLR4 in cancer stemness. We reported that TLR4‐AKT signaling pathway was activated by lipopolysaccharides (LPS) in HCC cell lines to enhance the cancer stemness capacity, which was reflected by the increased percentage of CD133+CD49f+ population and side population, enhanced sphere formation, and the upregulation of stemness marker gene‐SOX2. Downregulation of SOX2 attenuated the enhanced HCC stemness induced by LPS, indicating SOX2 as a downstream mediator of LPS‐TLR4 signaling. The role of LPS‐TLR4 signaling in inducing HCC stemness was further confirmed by tumor xenograft experiment in vivo. Taken together, our findings provide a novel therapeutic target to prevent the recurrence of HCC.
Synthesis, Antimicrobial Activities, and Molecular Docking Studies of Dihydrotriazine Derivatives Bearing a Quinoline Moiety
Authors: Bai Xueqian , Chen Ying , Liu Zhe , Zhang Linhao , Zhang Tianyi , Feng Bo
Published: April 2019

In this article, three series of dihydrotriazine derivatives bearing a quinoline moiety (5a, 5b, 8a–8c, and 9a–9m) have been designed, synthesized, and evaluated as antibacterial agents. Compounds 8a–8c were found to be the most potent of all of the compounds tested with an MIC value of 1 μg/mL against several Gram‐positive (S. aureus 4220 and MRSA CCARM 3506) and Gram‐negative (E. coli 1924) strains of bacteria. In addition, 3‐[4‐amino‐6‐(phenethylamino)‐2,5‐dihydro‐1,3,5‐triazin‐2‐yl)‐6‐[(3‐chlorobenzyl)oxy]quinolin‐2‐ol (8a) showed potent inhibitory activity (MIC=2 μg/mL) against Pseudomonas aeruginosa 2742, indicating that its antibacterial spectrum is similar to those of the positive controls gatifloxacin and moxifloxacin. Structure‐activity relationships (SAR) analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency of the quinoline compounds. In vitro enzyme study implied that compound 8a also displayed DHFR inhibition.
MiR‐19b‐3p regulates osteogenic differentiation of PDGFRα+ muscle cells by specifically targeting PTEN
Authors: Zhu Yong , Long Hai‐Tao , Zeng Lei , Tang Yi‐fu , Zhao Rui‐bo , Lin Zhang‐yuan , Zhao Shu‐shan , Cheng Liang
Published: April 2019

Heterotopic ossification (HO) is a common disturbing complication of intra‐articular fractures. Its prevention and treatment are still difficult as its pathogenesis is unclear. It was reported that PDGFRα+ muscle cells in skeletal muscle may participate in the formation of HO; however, the specific mechanism is still unknown. This study investigated the function of miR‐19b‐3p in osteogenic differentiation of PDGFRα+ muscle cells. MiR‐19b‐3p was upregulated during PDGFRα+ muscle cell osteogenic differentiation. The exogenous expression of miR‐19b‐3p led to an increase in osteogenic marker gene transcription and translation during the osteogenic differentiation of PDGFRα+ muscle cells. Furthermore, both alkaline phosphatase and alizarin red staining increased in miR‐19b‐3p mimic transfected cells. Over‐expression of miR‐19b‐3p led to the down‐regulation of gene of phosphate and tension homology deleted on chromosome ten (PTEN). Additionally, the dual luciferase reporter assay demonstrated that PTEN was a direct target of miR‐19b‐3p. The increase of osteocalcin, osteopontin, and Runt‐related transcription factor 2 protein levels induced by ectopic miR‐19b‐3p expression could be partially reversed by PTEN over‐expression. In conclusion, our results suggested that miR‐19b‐3p may be a promising target in inhibiting PDGFRα+ muscle cell osteogenic differentiation and treatment of HO.
The absorption of apolipoprotein E by damaged neurons facilitates neuronal repair
Authors: Chen Min , Xie Ming , Peng Chao , Long Shuangqi
Published: April 2019

Traumatic brain injury (TBI) is one of the common diseases diagnosed in departments of neurosurgery. Apolipoprotein E (apoE) can improve the prognosis of TBI. In this study, we aimed to explore the effect of apoE in mechanically damaging neurons as well as its underlying molecular mechanism. Western blot analysis and immunofluorescence assay was performed to detect the expressions of associated proteins. The expressions of apoE, p38, and phosphorylation of P38 were increased in mechanically injured neurons compared with those of the non‐injured ones. Neurons transfected into silencing apoE had no clear difference in the expression of apoE between injured and non‐injured neurons. However, in the injured neurons, silencing apoE could significantly decrease apoE and p‐P38 expressions. Oligodendrocytes were cultured in the medium collected from mechanically damaged si‐apoE neurons. Furthermore, we found that mechanically injured si‐apoE neurons could absorb the secreted apoE from the oligodendrocyte medium of the injured si‐apoE‐neuron, along with increasing of p‐P38 expression at 24 h. The p38 MAPK inhibitor BIRB 796 almost did not affect the apoE expression at 24 h, but significantly reduced the p‐P38 level at 24 and 72 h in injured si‐apoE neurons cultured with oligodendrocyte medium of the injured si‐apoE‐neurons. Moreover, our result showed that neuronal repair effects in normal neurobasal medium (lowest levels of apoE and p‐P38) and BIRB 796 medium (low level of p‐P38) were more slow than those in the oligodendrocyte medium of the injured si‐apoE‐neurons. To conclude, our data demonstrated that mechanical injury of neurons stimulated oligodendrocytes to secrete apoE. The injured neurons could absorb secreted apoE. The expression of apoE contributed to the activation of p38 MAPK, which facilitated neuron repair.
Rational Redesign of a Regioselective Hydroformylation Catalyst for 3‐Butenoic Acid by Supramolecular Substrate Orientation
Authors: Bai Shao‐Tao , Sinha Vivek , Kluwer Alexander M. , Linnebank Pim R. , Abiri Zohar , de Bruin Bas , Reek Joost N. H.
Published: April 2019

Rational design of ligands for regioselective transformations is one of the long pursuing targets in the field of transition metal catalysis. In the current contribution, we report OrthoDIMphos (L2), a ligand that was designed for regioselective hydroformylation of 3‐butenoic acid and its derivatives. The previously reported ParaDIMphos (L1) based hydroformylation catalyst was very selectively producing the linear aldehyde when substrates were bound in its pocket via hydrogen bonding. However, the distance between the binding site and the rhodium center was too large to also address 3‐butenoic acid and its derivatives. We therefore designed OrthoDIMphos (L2) as new ligand which has a shorter distance between the DIM‐receptor and the catalytic center. The OrthoDIMphos (L2) based catalyst displays high regioselectivity in the hydroformylation of 3‐butenoic acid and challenging internal alkene analogue (l/b up to 84, TON up to 630), which cannot be achieved with the ParaDIMphos (L1) catalyst. Detailed studies show that the OrthoDIMphos (L2) based catalyst forms a dimeric structure, in which the two ligands coordinate to two different rhodium metals. Substrate binding to the DIM‐receptor is required to break up the dimeric structure, and as only the monomeric analogue is a selective catalyst, the outcome of the reaction is dependent on substrate concentration used in catalysis.
Metal Silicide Nanosphere Decorated Carbon‐Rich Polymer‐Derived Ceramics: Bifunctional Electrocatalysts towards Oxygen and their Application in Anion Exchange Membrane Fuel Cells
Authors: Abinaya S. , Moni Prabu , Parthiban V. , Sahu Akhila Kumar , Wilhelm Michaela
Published: April 2019

The current hindrance in the commercialization of electrochemical devices such as fuel cells and metal–air batteries is the high cost and poor stability of widely employed noble‐metal‐based electrocatalysts. In this report, a new intermetallic nickel/cobalt silicide‐decorated carbon‐rich silica‐based ceramic composites (Co/SiOC or Ni/SiOC) were successfully synthesized as alternative bifunctional electrocatalysts. The oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) kinetics of the prepared composite materials were evaluated by electrochemical characterization. Co/SiOC exhibited more positive ORR kinetics with the onset potential of 0.87 V vs. RHE compared to that of Ni/SiOC, which is slightly lower compared to Pt/C. Conversely, Ni/SiOC exhibits a 50 mV more positive OER onset potential compared to Co/SiOC with almost similar OER kinetics to RuO2. The bifunctional ability concluded that Ni/SiOC was a good bifunctional catalyst with an oxygen electrode potential 0.89 V. As Co/SiOC performs as a better ORR catalyst, it was utilized as a cathode catalyst for the construction of anion exchange membrane fuel cell and its fuel cell performance was evaluated. The Co/SiOC composites produce a peak power density of 54 mW/cm2, representing a satisfactory result when compared with Pt/C. The results reveal that the intermetallic nickel/cobalt silicide nanosphere decorated ceramic materials can have a promising future as efficient alternative electrocatalysts in electrochemical devices.
Model checking ontology‐driven reasoning agents using strategy and abstraction
Authors: Rakib Abdur , Faruqui Rokan Uddin
Published: April 2019

We present a framework for the modelling, specification, and verification of ontology‐driven multi‐agent rule‐based systems (MASs). We assume that each agent executes in a separate process and that they communicate via message passing. The proposed approach makes use of abstract specifications to model the behaviour of some of the agents in the system and exploits information about the reasoning strategy adopted by the agents. Abstract specifications are given as Linear Temporal Logic (LTL) formulas which describe the external behaviour of the agents, allowing their temporal behaviour to be compactly modelled. Both abstraction and strategy have been combined in an automated model checking encoding tool Tovrba for rule‐based multi‐agent systems which allows the system designer to specify information about agents' interaction, behaviour, and execution strategy at different levels of abstraction. The Tovrba tool generates an encoding of the system for the Maude LTL model checker, allowing properties of the system to be verified.
Diversity‐dependent plant–soil feedbacks underlie long‐term plant diversity effects on primary productivity
Authors: Guerrero‐Ramírez Nathaly R. , Reich Peter B. , Wagg Cameron , Ciobanu Marcel , Eisenhauer Nico
Published: April 2019

Although diversity‐dependent plant–soil feedbacks (PSFs) may contribute significantly to plant diversity effects on ecosystem functioning, the influences of underlying abiotic and biotic mechanistic pathways have been little explored to date. Here, we assessed such pathways with a PSF experiment using soil conditioned for ≥12 yr from two grassland biodiversity experiments. Model plant communities differing in plant species and functional group richness (current plant diversity treatment) were grown in soils conditioned by plant communities with either low‐ or high‐diversity (soil history treatment). Our results indicate that plant diversity can modify plant productivity through both diversity‐mediated plant–plant and plant–soil interactions, with the main driver (current plant diversity or soil history) differing with experimental context. Structural equation modeling suggests that the underlying mechanisms of PSFs were explained to a significant extent by both abiotic and biotic pathways (specifically, soil nitrogen availability and soil nematode richness). Thus, effects of plant diversity loss on plant productivity may persist or even increase over time because of biotic and abiotic soil legacy effects.
Reproductive class influences risk tolerance during denning and spring for American black bears (Ursus americanus)
Authors: Gantchoff M. G. , Beyer D. , Belant J. L.
Published: April 2019

Den sites are important for many species’ ecology, and individuals should choose den sites that minimize risk and maximize energy gain. We examined den site selection and spring space use for black bears (Ursus americanus) at the individual level, and analyzed support for the anthropogenic risk avoidance and infanticide avoidance hypotheses. We obtained telemetry data for 94 individual bears (71 F and 23 M) and collected 162 den locations from Michigan (2009–2011 and 2013–2015), Missouri (2010–2016), and Mississippi (2008–2017), USA. Of 71 females, 37 were monitored during multiple reproductive states. We used generalized linear mixed models to evaluate the influence of reproductive state (female with cubs, female with yearlings, female alone, or male) on den distance to the nearest road, two road indexes (den emergence and spring), spring home range size, mean spring road distance, and a NDVI selection index. All black bears, except females with cubs, chose den locations farther from roads than available to them, supporting the anthropogenic risk avoidance hypothesis. Additionally, females with cubs displayed the smallest spring home ranges among females, as well as denned closer to roads and used areas closer to roads during spring than females with yearlings, supporting the infanticide avoidance hypothesis. The differential responses by the same females when having cubs or yearlings point to strategies to maximize reproductive success. By investigating behavior considering individual availability, we revealed patterns that might not be detected by population‐level assessments.
Sequential Phase Transitions with Switchable Dielectric Constant in a Metal‐Free Ionic Crystal
Authors: Jing Jing , Gao Ji‐Xing , Fan Guang‐Meng , Shi Chao , Gong Zhi‐Xin , Hua Miao‐Miao , Zhang Yi , Shuai Cijun , Ye Heng‐Yun
Published: April 2019

An intriguing area for developing smart devices is metal‐free materials. These materials have simple preparation, low processing temperature and environmentally‐friendly processing of the crystal. Stimuli‐responsive materials, which have been developed switchable property of dielectric constant in most inorganic‐organic hybrid compounds, are rarely found in metal‐free materials. Herein, a metal‐free ionic crystal compound, [3R‐(+)‐3‐AP][ClO4]2 (1, 3R‐(+)‐3‐AP = 3R‐(+)‐3‐aminopyrrolidine cation), was synthesized and characterized. The structure is featured by zero‐dimensional supramolecular block structure built from the [3R‐(+)‐3‐AP][ClO4]2 units. Compound 1 undergoes sequential reversible phase transitions at 350/373 K and 430/441 K, respectively. Variable‐temperature single crystal structural analysis and dielectric constant measurements reveal changes of the crystal lattice dynamics, i.e., the twisting motion of the perchlorate anions and the dynamic changes of the [3R‐(+)‐3‐AP] cations, are the origin of the phase transitions. This finding reveals that the amphidynamic metal‐free crystal can evolve rich electrical properties once the dynamic components (especially the polar ones) undergo order‐disorder transitions, such as temperature‐responsive dielectric switching.
A Precious Catalyst: Rhodium‐Catalyzed Formic Acid Dehydrogenation in Water
Authors: Fink Cornel , Laurenczy Gábor
Published: April 2019

The performance of rhodium complex [Cp*Rh(bis(pyrazol‐1‐yl)methane)Cl]Cl was evaluated for formic acid dehydrogenation in aqueous solution. Solid‐state X‐ray diffraction helped to confirm the catalyst structure. Multinuclear NMR spectroscopy was employed to follow the dehydrogenation of formic acid. The reactions have been carried out in high‐pressure NMR sapphire tubes. An activation energy of +77.19 ± 4 kJ/mol was determined via an Arrhenius plot, which is in good agreement with literature findings. The catalyst afforded a TOF of 1086 h–1 and exhibited good stability. Based on our observations and literature, we propose a catalytic cycle.
Bioturbation and erosion rates along the soil‐hillslope conveyor belt, part 1: Insights from single‐grain feldspar luminescence
Authors: Román‐Sánchez Andrea , Reimann Tony , Wallinga Jakob , Vanwalleghem Tom
Published: April 2019

The interplay of bioturbation, soil production and long‐term erosion–deposition in soil and landscape co‐evolution is poorly understood. Single‐grain post‐infrared infrared stimulated luminescence (post‐IR IRSL) measurements on sand‐sized grains of feldspar from the soil matrix can provide direct information on all three processes. To explore the potential of this novel method, we propose a conceptual model of how post‐IR IRSL‐derived burial age and fraction of surface‐visiting grains change with soil depth and along a hillslope catena. We then tested this conceptual model by comparison with post‐IR IRSL results for 15 samples taken at different depths within four soil profiles along a hillslope catena in the Santa Clotilde Critical Zone Observatory (southern Spain).

In our work, we observed clear differences in apparent post‐IR IRSL burial age distributions with depth along the catena, with younger ages and more linear age–depth structure for the hill‐base profile, indicating the influence of lateral deposition processes. We noted shallower soils and truncated burial age–depth functions for the two erosional mid‐slope profiles, and an exponential decline of burial age with depth for the hill‐top profile. We suggest that the downslope increase in the fraction of surface‐visiting grains at intermediate depths (20 cm) indicates creep to be the dominant erosion process.

Our study demonstrates that single‐grain feldspar luminescence signature‐depth profiles provide a new way of tracing vertical and lateral soil mixing and transport processes. In addition, we propose a new objective luminescence‐based criterion for mapping the soil‐bedrock boundary, thus producing soil depths in better agreement with geomorphological process considerations. Our work highlights the possibilities of feldspar single grain techniques to provide quantitative insights into soil production, bioturbation and erosion–deposition. © 2019 The Authors. Earth Surface Processes and Landforms Published by John Wiley & Sons Ltd.
Migration of barchan dunes in the western Quruq Desert, northwestern China
Authors: Yang Junhuai , Dong Zhibao , Liu Zhengyao , Shi Weikang , Chen Guoxiang , Shao Tianjie , Zeng Hanmin
Published: April 2019

Barchan dunes are common on Earth, Mars and Titan. Previous studies have shown that their formation, migration and evolution are influenced by the wind regime and other factors, but details vary among regions. Understanding barchan morphology and migration will both improve our understanding of dune geomorphology and provide a basis for describing the environmental conditions that affect the formation and development of these dunes on Earth and other planets. Here, we provide detailed measurements of barchan dune migration in China's Quruq Desert, in the lower reaches of the Tarim River. We monitored their migration direction and rate, and their morphological changes during migration, by comparing Google Earth images acquired in 2003 and 2014. The dunes migrated west‐southwest, close to the local resultant drift direction. The migration rate averaged 8.9 to 32.1 m year−1, with obvious spatial variation. In addition to the wind regime, the migration rate depended on dune morphology, density and vegetation cover; the rate was negatively related to dune height, density and vegetation cover, but positively linearly related to the length/width ratio (LU/W) and to the decrease in this ratio from 2003 to 2014. We found correlations among the dune morphometric parameters, but the relationships were weaker than in previous research. Due to the complexity of the factors that affect the processes that underlie sand dune development and migration, the morphological changes during dune migration were also complex. Our measurements suggest that the aeolian environment played a dominant role in dune migration and its spatial variation in the Quruq Desert. These results will support efforts to control dune migration in the western Quruq Desert and improve our understanding of dune morphodynamics. © 2019 John Wiley & Sons, Ltd.
Vitrimerization: A Novel Concept to Reprocess and Recycle Thermoset Waste via Dynamic Chemistry
Authors: Yue Liang , Bonab Vahab Solouki , Yuan Dian , Patel Ammar , Karimkhani Vahid , Manas‐Zloczower Ica
Published: April 2019

A new approach for reprocessing of existing thermoset waste is presented. This work demonstrates that unrecyclable thermoset materials can be reprocessed using the concept of associative dynamic bonding, vitrimers. The developed recycling methodology relies on swelling the thermoset network into a solution of a catalyst, which enables transesterification reactions allowing dynamic bond exchange between ester and hydroxyl groups within the thermoset network. Thermal and mechanical properties for recycled polyurethane and epoxy networks are studied and a strategy to maintain the properties of recycled materials is discussed. The developed methodology promises recycling and even upcycling and reprocessing of previously thought intractable materials. Moreover, processability of vitrimerized thermosets with common thermoplastic manufacturing methods opens up the possibility of tuning recycled networks by adding nanoparticles. This flexibility keeps the application window of recycled thermosets very broad.
Digital Management of Solar Energy En Route to Energy Self‐Sufficiency
Authors: Pagliaro Mario , Meneguzzo Francesco
Published: April 2019

The Internet of Things approach to manage clean electricity produced from sun, wind, and water is, alongside the hydrogen fuel cell and the Li‐ion battery, the key enabling technology for the transition to 100% renewable energy. Practical examples from distant countries are used to show how today's digital control technology is actually used to ease the generation and utilization of clean, reliable, and cheap solar energy on an annual basis. The conclusions are of relevance also to the redesign of energy education programs in response to dramatic changes in energy technologies.
The Constructions and Pyrolysis of 3D Kerogen Macromolecular Models: Experiments and Simulations
Authors: Wang XiaoHe , Huang XianFu , Lin Kui , Zhao Ya‐Pu
Published: April 2019

Kerogens are extracted from deep shales to study pyrolysis of deep shale samples. The 2D molecular models of kerogens are obtained by a series of physical and chemical experiments by which the macromolecular models of kerogens are constructed. Then, the reasonable 3D macromolecular models are established by molecular mechanics and global energy minimization. The effects of temperature and heating rate on the chemical kinetics of kerogen pyrolysis are studied using reactive force field (ReaxFF). The hybrid molecular dynamics/force‐biased Monte Carlo (MD/fbMC) approach is used to simulate the pyrolytic process at the experimental temperature, which is lower than the conventional one. The gaseous products and residues obtained by the simulations agree with the experimental results, which means a reliable simulation method for pyrolysis at experimental temperature is provided. This study constructs the rational macromolecular models of kerogen by experiments, and proposes the mechanisms of typical reactions of kerogen pyrolysis, which may help in understanding the formation of shale oil and gas.
Glutamate versus GABA in neuron–oligodendroglia communication
Authors: Habermacher Chloé , Angulo María C. , Benamer Najate
Published: April 2019

In the central nervous system (CNS), myelin sheaths around axons are formed by glial cells named oligodendrocytes (OLs). In turn, OLs are generated by oligodendrocyte precursor cells (OPCs) during postnatal development and in adults, according to a process that depends on the proliferation and differentiation of these progenitors. The maturation of OL lineage cells as well as myelination by OLs are complex and highly regulated processes in the CNS. OPCs and OLs express an array of receptors for neurotransmitters, in particular for the two main CNS neurotransmitters glutamate and GABA, and are therefore endowed with the capacity to respond to neuronal activity. Initial studies in cell cultures demonstrated that both glutamate and GABA signaling mechanisms play important roles in OL lineage cell development and function. However, much remains to be learned about the communication of glutamatergic and GABAergic neurons with oligodendroglia in vivo. This review focuses on recent major advances in our understanding of the neuron–oligodendroglia communication mediated by glutamate and GABA in the CNS, and highlights the present controversies in the field. We discuss the expression, activation modes and potential roles of synaptic and extrasynaptic receptors along OL lineage progression. We review the properties of OPC synaptic connectivity with presynaptic glutamatergic and GABAergic neurons in the brain and consider the implication of glutamate and GABA signaling in activity‐driven adaptive myelination.
Patient perspectives and treatment regret after de‐escalated chemoradiation for human papillomavirus‐positive oropharyngeal cancer: Findings from a phase II trial
Authors: Shaverdian Narek , Hegde John V. , Felix Carol , Hsu Sophia , Basehart Vincent , Steinberg Michael L. , Chen Allen M.
Published: April 2019

Background

We evaluated priorities, expectations, and regret among patients treated on a phase II trial of de‐escalated chemoradiation for human papillomavirus (HPV)‐positive oropharyngeal cancer.

Methods

Eligibility included stage III/IV squamous cell carcinoma of the oropharynx, p16‐positivity, age ≥18 years, and Zubrod score 0‐1. Participants were surveyed with validated measures evaluating their treatment experience.

Results

Twenty‐four of 27 (89%) patients participated with a median follow‐up of 24 months. Twenty‐three subjects (96%) selected “being cured” or “living as long as possible” as top priority. No patient reported any regret about the decision to enroll on a de‐escalation protocol. Sixteen participants (67%) found retrospectively reported long‐term swallowing function to be either better than or as originally expected.

Conclusions

These data offer a baseline landscape of perspectives and priorities for patients treated with de‐escalation for HPV‐positive oropharyngeal carcinoma and provide support to the fundamental premise underlying ongoing efforts to establish a new standard of care.