bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulsed Laser Modulated Shock Transition from Liquid Metal Nanoparticles to Mechanically and Thermally Robust Solid–Liquid Patterns
Authors: Deng Biwei , Cheng Gary J. 
Published: February 2019

AbstractIn this work, a general mechanism is discovered to form liquid‐metal‐based, stable and stretchable conductive patterns on rigid and soft substrates. It is discovered that pulsed laser irradiation of liquid metal nanoparticles (LMNPs) with tunable conditions can induce transformation to stable and stretchable solid–liquid (S–L) dual phases on various surfaces. Formation of this unique solid–liquid composite phase is the key to change the wetting behavior of the conductive patterns on various substrates and enables mechanically stable patterns on various substrates. Pulsed‐laser‐driven thermo‐mechanical shock momentum is important for rupture and joining of the LMNPs, providing much better control than the traditional mechanical sintering. The solid nanophase forms a nanoporous matrix filled with and wetted by the LM, thereby providing a stabilization mechanism for the S–L composite patterned thin film. The mechanical and thermal reliability of the solid–liquid patterns is investigated. The S–L patterns can stretch up to 30% strain and cycle stably for 7000 cycles. It can be heated up to 177 °C with an input power of 0.58 W. The solid–liquid composite film provides great opportunity for various applications as a flexible conductor with unique mechanical and physics properties and further inspires design of LM devices for completely exposed applications.
Improved Charge Extraction Beyond Diffusion Length by Layer‐by‐Layer Multistacking Intercalation of Graphene Layers inside Quantum Dots Films
Authors: Chen Wenjun , Castro Joshua , Ahn Seungbae , Li Xiaochen , Vazquez‐Mena Oscar 
Published: February 2019

AbstractCharge collection is critical in any photodetector or photovoltaic device. Novel materials such as quantum dots (QDs) have extraordinary light absorption properties, but their poor mobility and short diffusion length limit efficient charge collection using conventional top/bottom contacts. In this work, a novel architecture based on multiple intercalated chemical vapor deposition graphene monolayers distributed in an orderly manner inside a QD film is studied. The intercalated graphene layers ensure that at any point in the absorbing material, photocarriers will be efficiently collected and transported. The devices with intercalated graphene layers have superior quantum efficiency over single‐bottom graphene/QD devices, overcoming the known restriction that the diffusion length imposes on film thickness. QD film with increased thickness shows efficient charge collection over the entire λ ≈ 500–1000 nm spectrum. This architecture could be applied to boost the performance of other low‐cost materials with poor mobility, allowing efficient collection for films thicker than their diffusion length.
Strong Surface Bonding of Polysulfides by Teflonized Carbon Matrix for Enhanced Performance in Room Temperature Sodium‐Sulfur Battery
Authors: Vijaya Kumar Saroja Ajay Piriya , Muthusamy Kamaraj , Sundara Ramaprabhu 
Published: February 2019

AbstractThe practical application of room temperature sodium‐sulfur (Na–S) battery remains far away from the market due to the poor coulombic efficiency and cyclic stability which in turn arises from high dissolution of intermediate polysulfides in carbonate‐based electrolytes, slow reaction kinetics, and low electrical conductivity of sulfur. In this aspect, an advanced cathode structure by incorporating Teflon‐lined conductive carbon substrate (TCS) as a supporting cathode to efficiently immobilize the migration of soluble polysulfides to the anode, as well as enhance the conductivity during the polysulfide conversion, is presented here. After inclusion of TCS, the cell delivers a specific capacity of 800 mAh g−1 at 0.1C (1C = 1672 mA g−1) with 85% enhancement in specific capacity. Also, a stable cyclic stability of about 300 cycles with an excellent capacity retention of about 93% and coulombic efficiency of nearly 100% is obtained. Teflon, which has a linear carbon chain surrounded completely by fluorine atoms, acts as the anchoring sites for trapping the intermediate sodium polysulfides. This study provides a simple approach of controlling the shuttling effect, which can be beneficial for the development of high energy density room temperature Na–S battery.
2D SnO/In2O3 van der Waals Heterostructure Photodetector Based on Printed Oxide Skin of Liquid Metals
Authors: Alsaif Manal M. Y. A. , Kuriakose Sruthi , Walia Sumeet , Syed Nitu , Jannat Azmira , Zhang Bao Yue , Haque Farjana , Mohiuddin Md , Alkathiri Turki , Pillai Naresh , Daeneke Torben , Ou Jian Zhen , Zavabeti Ali 
Published: February 2019

AbstractHeterostructures assembled from atomically thin materials have led to a new paradigm in the development of the next‐generation high‐performing functional devices. However, the construction of the ultrathin van der Waals (vdW) heterostructures is challenging and/or limited to materials with layered crystal structures. Herein, liquid metal vdW transfer method is used to construct large area heterostructures of atomically thin metal oxides of p‐SnO/n‐In2O3 with ease. The heterostructure exhibits both outstanding photodetectivity of 5 × 109 Jones and photoresponsivity of 1047 A W−1 with fast response time of ≤1 ms under illumination of the 280 nm light. Such excellent performances are due to the formation of the narrow bandgap of the staggered gap at the p–n junction produced by the high‐quality SnO/In2O3 heterostructure. The facile production of high‐quality vdW heterostructures using the liquid metal–based method therefore provides a promising pathway for realizing future optoelectronic devices.
Adsorption and Exchangeability of Fibronectin and Serum Albumin Protein Corona on Annealed Polyelectrolyte Multilayers and Their Consequences on Cell Adhesion
Authors: Muzzio Nicolas E. , Pasquale Miguel A. , Rios Xabier , Azzaroni Omar , Llop Jordi , Moya Sergio E. 
Published: February 2019

AbstractPolyelectrolyte multilayers (PEMs) based on biopolyelectrolytes are highly appealing for the surface engineering of biomaterials and the tuning of cell response and phenotypes for biomedical applications. However, cell adhesion is limited on biopolyelectrolyte PEMs. Thermal annealing provides a simple means to increase or decrease cell adhesion on PEMs. The work presented here aims to understand cellular interactions with annealed PEMs based on the adsorption and exchangeability of two model proteins: fibronectin (FN), an adhesion protein, and bovine serum albumin (BSA), a nonadhesion protein. Protein adsorption and exchangeability are studied on annealed poly‐l‐lysine (PLL)/sodium alginate (Alg) and chitosan (Chi)/hyaluronic acid (HA) PEMs using [131I] radiolabeled proteins and gamma counting. Upon annealing cell adhesion is enhanced on PLL/Alg multilayers and decreased on Chi/HA multilayers. For PLL/Alg PEMs, annealing increases adsorption of both FN and BSA and reduces exchangeability. For Chi/HA multilayers, annealing increases BSA adsorption but decreases FN deposition, accompanied by a greater exchangeability. Changes in topographic features of deposited proteins on annealed PLL/Alg hint on changes in the 3D structure of the proteins. Circular dichroism shows that FN retains a large β‐sheet contribution upon adsorption to both annealed and unannealed PLL/Alg PEMs, also suggesting changes in tertiary structure.
Chitooligosaccharide Biguanide Repairs Islet β‐Cell Dysfunction by Activating the IRS‐2/PI3K/Akt Signaling Pathway in Type 2 Diabetic Rats
Authors: Zou Yalu , Wang Yuanyuan , Zhang Shengsheng , Wu Yuntang , Liu Xiaofei 
Published: February 2019

AbstractIslet β cell failure is a critical metabolic disorder in the development of type 2 diabetes (T2DM), and the decreased viability and dysfunction of β cells accelerate diabetic pathogenesis in association with higher mortality. In this study, the therapeutic effects of chitooligosaccharide biguanide (COSG), which is similar in structure to metformin and has negligible side effects, on islet β‐cell dysfunction and the possible mechanism are explored. Streptozocin‐induced diabetic rats are administered COSG via daily intragastric gavage for 8 weeks. COSG significantly controlled body weight loss, attenuated glucose levels in blood and urine, and increased serum insulin. Histological examination of the pancreas reveals that COSG also alleviated pancreatic atrophy in T2DM rats. Furthermore, COSG stimulated insulin receptor substrate‐2 (IRS‐2) signaling in rat islet β cells, thereby mediating the activation of the phosphatidylinositol 3 kinase/protein kinase (PI3K/Akt) signaling pathway. In addition, COSG promoted downstream forkhead transcription factor O1 (FoxO1) nuclear output to potentially activate pancreas duodenum homeobox‐1 (PDX‐1)/glucose transporter type‐2 (GLUT‐2)/glucose kinase (GCK) pathway‐regulated insulin secretion. COSG also inhibited the glycogen synthase kinase‐3β (GSK‐3β)/caspase‐3 pathway to prevent cell apoptosis. The intrinsic protective effects of COSG on the impaired insulin signaling system to delay β‐cell apoptosis, increase β‐cell growth and proliferation, improve β‐cell function and promote insulin secretion highlight the possibilities of COSG as a novel strategy for the prevention of T2DM.
Transport Properties of Topological Semimetal Tungsten Carbide in the 2D Limit
Authors: Wang Cheng , Chen Long , Liu Zhen , Liu Zhibo , Ma Xiu‐Liang , Xu Chuan , Cheng Hui‐Ming , Ren Wencai , Kang Ning 
Published: February 2019

AbstractRecent theoretical calculations and spectroscopy measurements have shown that several materials with the tungsten carbide‐type structure, such as molybdenum phosphide and tungsten carbide (WC), are a new type of topological semimetal hosting triply degenerate nodal points. So far, most of experimental studies are performed on large‐size bulk crystal. 2D nanostructures, with large surface‐to‐volume ratio, are expected to provide an attractive system for probing topological surface states and the development of device applications. Here the transport characterization of high‐quality ultrathin WC single crystals is reported. The magnetoresistance (MR) shows a strong anisotropic behavior, which may be attributed to the transport anomalies of three‐component fermions as theoretically proposed. The scaling analysis reveals the presence of the surface states in WC. The observation of the nonsaturating MR in strong magnetic fields, together with nonlinear and strong temperature dependent Hall effect, is consistent with the proposed multiple bands character of carriers in WC. In addition, a low‐temperature upturn in the resistance is observed, indicating that electron–electron interaction plays a prominent role in charge transport. The results demonstrate that the ultrathin WC crystals offer a potential platform for exploring exotic transport properties arising from the three‐component fermions in the 2D limit.
Atomic Fe‐Doped MOF‐Derived Carbon Polyhedrons with High Active‐Center Density and Ultra‐High Performance toward PEM Fuel Cells
Authors: Deng Yijie , Chi Bin , Li Jing , Wang Guanghua , Zheng Long , Shi Xiudong , Cui Zhiming , Du Li , Liao Shijun , Zang Ketao , Luo Jun , Hu Yongfeng , Sun Xueliang 
Published: February 2019

AbstractA metalorganic gaseous doping approach for constructing nitrogen‐doped carbon polyhedron catalysts embedded with single Fe atoms is reported. The resulting catalysts are characterized using scanning transmission electron microscopy, X‐ray photoelectron spectroscopy, and X‐ray absorption spectroscopy; for the optimal sample, calculated densities of Fe–Nx sites and active N sites reach 1.75812 × 1013 and 1.93693 × 1014 sites cm‐2, respectively. Its oxygen reduction reaction half‐wave potential (0.864 V) is 50 mV higher than that of 20 wt% Pt/C catalyst in an alkaline medium and comparable to the latter (0.78 V vs 0.84 V) in an acidic medium, along with outstanding durability. More importantly, when used as a hydrogen–oxygen polymer electrolyte membrane fuel cell (PEMFC) cathode catalyst with a catalyst loading as low as 1 mg cm‐2 (compared with a conventional loading of 4 mg cm‐2), it exhibits a current density of 1100 mA cm‐2 at 0.6 V and 637 mA cm‐2 at 0.7 V, with a power density of 775 mW cm‐2, or 0.775 kW g–1 of catalyst. In a hydrogen–air PEMFC, current density reaches 650 mA cm‐2 at 0.6 V and 350 mA cm‐2 at 0.7 V, and the maximum power density is 463 mW cm‐2, which makes it a promising candidate for cathode catalyst toward high‐performance PEMFCs.
Molecular Level Insight into Enhanced n‐Type Transport in Solution‐Printed Hybrid Thermoelectrics
Authors: Zaia Edmond W. , Gordon Madeleine P. , Niemann Valerie , Choi Jaeyoo , Chatterjee Ruchira , Hsu Chih‐Hao , Yano Junko , Russ Boris , Sahu Ayaskanta , Urban Jeffrey J. 
Published: February 2019

AbstractPerylene diimide (PDI) derivatives hold great promise as stable, solution‐printable n‐type organic thermoelectric materials, but as of yet lack sufficient electrical conductivity to warrant further development. Hybrid PDI‐inorganic nanomaterials have the potential to leverage these physical advantages while simultaneously achieving higher thermoelectric performance. However, lack of molecular level insight precludes design of high performing PDI‐based hybrid thermoelectrics. Herein, the first explicit crystal structure of these materials is reported, providing previously inaccessible insight into the relationship between their structure and thermoelectric properties. Allowing this molecular level insight to drive novel methodologies, simple solution‐based techniques to prepare PDI hybrid thermoelectric inks with up to 20‐fold enhancement in thermoelectric power factor over the pristine molecule (up to 17.5 µW mK−2) is presented. This improved transport is associated with reorganization of organic molecules on the surface of inorganic nanostructures. Additionally, outstanding mechanical flexibility is demonstrated by fabricating solution‐printed thermoelectric modules with innovative folded geometries. This work provides the first direct evidence that packing/organization of organic molecules on inorganic nanosurfaces is the key to effective thermoelectric transport in nanohybrid systems.
Rarity does not limit genetic variation or preclude subpopulation structure in the geographically restricted desert forb Astragalus lentiginosus var. piscinensis
Authors: Harrison Joshua G. , Forister Matthew L. , Mcknight Stephanie R. , Nordin Erin , Parchman Thomas L. 
Published: February 2019

Premise of the StudyCharacteristics of rare taxa include small population sizes and limited geographical ranges. The genetic consequences of rarity are poorly understood for most taxa. A small geographical range could result in reduced opportunity for isolation by distance or environment, thereby limiting genetic structure and variation, but few studies explore genetic structure at small spatial scales with sufficient resolution to test this hypothesis. Moreover, few comparative genetic studies exist among infrataxa differing in rarity. Here, we compare genetic variation among varieties of Astragalus lentiginosus differing in range size. Additionally, we ask if genetic structure exists in A. lentiginosus var. piscinensis, a rare taxon consisting of several thousand individuals that persist on ~8 km2 of alkaline soil.MethodsWe compared genetic variation among 11 varieties of A. lentiginosus differing in range size using a genotyping by sequencing (GBS) approach, which generated 11,475 single nucleotide polymorphisms (SNPs). We characterized genetic structure among subpopulations of A. lentiginosus var. piscinensis using a second GBS data set of 7274 SNPs and explored associations between genetic structure and environmental variation.Key ResultsWe found no association between genetic variation and range size among varieties of A. lentiginosus. Additionally, despite the extremely small range of A. lentiginosus var. piscinensis, we report a well‐defined genetic structure among subpopulations associated with microhabitat variation in soil composition.ConclusionsOur results suggest that fine scale genetic structure may exist within other rare Astragalus taxa and that rarity does not preclude the maintenance of genetic diversity in this genus.
Convergent Synthesis of Linear and Branched β(1,3)‐Glucans and Evaluation of their Binding Affinities to Dectin‐1
Authors: Hamagami Hiroki , Adachi Yoshiyuki , Ohno Naohito , Tanaka Hiroshi 
Published: February 2019

Abstractβ(1,3)‐Glucans, major components of fungal and bacterial cell‐walls, activate innate immunity by binding to dectin‐1 on immune cells. This paper describes a convergent synthesis of linear and multi‐branched β(1,3)‐glucan oligosaccharides for the study of structure‐activity relationships between β(1,3)‐glucans and their binding affinities to dectin‐1. The synthetic strategy highlights regioselective gold‐catalyzed glycosylations in the preparation of β(1,3)‐glucosides, as well as an efficient multiple glycosylation for the incorporation of several β(1,6)‐glucosides into β(1,3)‐glucosides. Based on this strategy, linear undecasaccharides and branched tetradecasaccharides, which had a partial structure of curdlan and schizophyllan, respectively, were successfully synthesized. Competitive inhibition experiments of these synthetic oligosaccharides revealed that the presence of an amino group at the reducing end was required for their binding to dectin‐1, whereas β(1,6)‐glucosides did not improve their binding affinities to dectin‐1.
Merging Photochemistry with Electrochemistry: Functional‐Group Tolerant Electrochemical Amination of C(sp3)−H Bonds
Authors: Wang Fei , Stahl Shannon S. 
Published: February 2019

AbstractDirect amination of C(sp3)−H bonds is of broad interest in the realm of C−H functionalization because of the prevalence of nitrogen heterocycles and amines in pharmaceuticals and natural products. Reported here is a combined electrochemical/photochemical method for dehydrogenative C(sp3)−H/N−H coupling that exhibits good reactivity with both sp2 and sp3 N−H bonds. The results show how use of iodide as an electrochemical mediator, in combination with light‐induced cleavage of intermediate N−I bonds, enables the electrochemical process to proceed at low electrode potentials. This approach significantly improves the functional‐group compatibility of electrochemical C−H amination, for example, tolerating electron‐rich aromatic groups that undergo deleterious side reactions in the presence of high electrode potentials.
On‐Surface Synthesis of Ethynylene‐Bridged Anthracene Polymers
Authors: Sánchez‐Grande Ana , de la Torre Bruno , Santos José , Cirera Borja , Lauwaet Koen , Chutora Taras , Edalatmanesh Shayan , Mutombo Pingo , Rosen Johanna , Zbořil Radek , Miranda Rodolfo , Björk Jonas , Jelínek Pavel , Martín Nazario , Écija David 
Published: February 2019

AbstractEngineering low‐band‐gap π‐conjugated polymers is a growing area in basic and applied research. The main synthetic challenge lies in the solubility of the starting materials, which precludes advancements in the field. Here, we report an on‐surface synthesis protocol to overcome such difficulties and produce poly(p‐anthracene ethynylene) molecular wires on Au(111). To this aim, a quinoid anthracene precursor with =CBr2 moieties is deposited and annealed to 400 K, resulting in anthracene‐based polymers. High‐resolution nc‐AFM measurements confirm the nature of the ethynylene‐bridge bond between the anthracene moieties. Theoretical simulations illustrate the mechanism of the chemical reaction, highlighting three major steps: dehalogenation, diffusion of surface‐stabilized carbenes, and homocoupling, which enables the formation of an ethynylene bridge. Our results introduce a novel chemical protocol to design π‐conjugated polymers based on oligoacene precursors and pave new avenues for advancing the emerging field of on‐surface synthesis.
The Structure of an Archaeal B‐Family DNA Polymerase in Complex with a Chemically Modified Nucleotide
Authors: Kropp Heike M. , Diederichs Kay , Marx Andreas 
Published: February 2019

AbstractArchaeal B‐family DNA polymerases (DNA pols) are the driving force of cutting‐edge biotechnological applications like next‐generation sequencing. The acceptance of chemically modified nucleotides by DNA pols is key to these technologies. Until now, no structural data have been available for these DNA pols in complex with modified substrates, which could build the basis for understanding interactions between the enzyme and the chemically modified nucleotide and for the further development of next‐generation nucleotides. For the first time, we crystallized an exonuclease‐deficient variant of the wild‐type B‐family KOD DNA pol with a modified nucleotide in a closed, ternary complex. We also crystalized the A‐family DNA pol KlenTaq with the same nucleotide. The reported structural data reveal how the protein and the DNA modulate two distinct conformations of the appended moiety in the A‐ and B‐family DNA pols and how these influence the processing of the modified nucleotide. Overall, this study provides first insight into the interplay between B‐family DNA pols and relevant modified substrates.
Mechanical properties of continuous bamboo fiber‐reinforced biobased polyamide 11 composites
Authors: Haddou Geoffrey , Dandurand Jany , Dantras Eric , Maiduc Huynh , Thai Hoang , Giang Nguyen Vu , Trung Tran Huu , Ponteins Philippe , Lacabanne Colette 
Published: February 2019

ABSTRACTThis study is devoted to the analysis of the properties of continuous bamboo fiber (BF)‐reinforced polyamide 11 (PA 11) composites. The SEM observations highlighted continuity between BFs and the polymeric matrix showing a high density of hydrogen bonds. The comparative calorimetric study of the matrix and its composites showed that the crystallinity of PA 11 was not modified by the presence of bamboo fibers. The physical aging observed in PA 11 is no more observed in composites due to physical interactions between PA 11 and BFs. The mechanical properties were investigated by tensile strength and dynamic mechanical analysis. The introduction of BFs enhanced Young's modulus of the matrix by a factor of 10. The presence of BFs also improved the storage shear modulus G′ over the whole temperature range. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47623.
Synthesis of Cyclopenta‐HBCs and their Regioselective Chlorination During Oxidative Cyclodehydrogenation
Authors: Hall Thomas B. J. , Hoggard Bryce R. , Larsen Christopher B. , Lucas Nigel T. 
Published: February 2019

AbstractHexa‐peri‐hexabenzocoronenes with a bay‐fused five‐membered ring are synthesized from fluorenyl precursors. The key oxidative cyclodehydrogenation step is accompanied by regioselective chlorination that is enhanced by methylation at the cyclopenta‐ring or increased reaction concentration. The CpHBC products undergo mild electrophilic aromatic bromination, without catalyst, to afford adducts suitable for π‐extension by cross‐coupling.