bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant Transcriptomic Responses to Herbivory
Authors: Heidel‐Fischer Hanna M. , Musser Richard O. , Vogel Heiko
Published: May 2017

For plants, insect attack is a complex stimulus which can be divided into three conceptual phases: pest recognition, signal transduction and deployment of defences. Here, we give an overview of the different stages of pest recognition by the plant, focusing on the transcriptomic aspects of these responses. Separating wound‐ and herbivore‐specific components of insect attack is as important as the distinction between attack from different feeding guilds such as chewing and piercing‐sucking herbivores to mount appropriate plant defence responses. We present a meta‐analysis of the existent microarray studies, intending to provide a better overview over plant gene expression data from a wider range of insect‐plant interaction studies. While the existent microarray studies give valid information about gene regulation in attacked plants, they also highlight the importance of synchronizations of experimental designs, as different model systems, controls and experimental time points make it hard to generalize results. Most of the past and current research has focused on single herbivore attack. In nature, however, simultaneous or subsequent attacks by insects are frequently observed, so we provide a brief overview over the current stage of knowledge of simultaneous attacks, ending with an outlook to future challenges in this field of science.
Plant‐Mediated Interactions among Insects within a Community Ecological Perspective
Authors: Poelman Erik H , Dicke Marcel
Published: May 2017

Plants may be visited by many species of insects during their life‐time. These insects include harmful herbivores above and below ground, as well as beneficial natural enemies of herbivores and pollinators. Moreover, these interactions may take place sequentially or simultaneously. Responses of plants in interactions with one species result in phenotypic changes that subsequently affect the performance and behaviour of other species. Thus, plants mediate interactions among their associated community members, and such indirect trait‐mediated interactions affect the structure of insect communities. As a consequence, plant‐mediated species interactions may also affect plant fitness.
The Altitudinal Niche‐Breadth Hypothesis in Insect‐Plant Interactions
Authors: Rasmann Sergio , Alvarez Nadir , Pellissier Loïc
Published: May 2017

Studies aiming at explaining specialization along latitudinal gradients of plant‐herbivore interactions have, to date, yielded inconclusive results. Here we propose the use of steep altitudinal gradients for dissecting factors driving evolution of polyphagy in insect herbivores. First, we test whether colonization of high elevation environment favours increased niche‐breadth in two disparate insect groups – the wood‐boring beetles and the pollinator group of bees – and show increased polyphagy at higher altitudes in both groups. We then assess classic assumptions transferred from the ‘latitude‐niche‐breadth hypothesis’, particularly the increase in environmental variability at high, compared to low, altitude. Finally, we discuss alternative mechanisms shaping the observed pattern of increased polyphagy in altitude, including variation in plant quality and predator pressure at different altitudes. We thus suggest evidence for the ‘altitude niche‐breadth hypothesis’, in which both abiotic and biotic conditions, including increased variability and an increase of the potential feeding niche‐breadth, promote evolution for increased insect polyphagy in altitude.
Exploratory study of the association of volumetric modulated arc therapy (VMAT) plan robustness with local failure in head and neck cancer
Authors: Liu Wei , Patel Samir H. , Harrington Daniel P. , Hu Yanle , Ding Xiaoning , Shen Jiajian , Halyard Michele Y. , Schild Steven E. , Wong William W. , Ezzell Gary E. , Bues Martin
Published: May 2017

This work is to show which is more relevant to cause local failures (LFs) due to patient setup uncertainty between the planning target volume (PTV) underdosage and the potential target underdosage subject to patient setup uncertainties in head and neck (H&N) cancer treated with volumetric‐modulated arc therapy (VMAT). Thirteen LFs in 10 H&N patients treated by VMAT were analyzed. Measures have been taken to minimize the chances of insufficient target delineation for these patients and the patients were clinically determined to have LF based on the PET/CT scan results by an experienced radiologist and then reviewed by a second experienced radiation oncologist. Two methods were used to identify the possible locations of LF due to underdosage: (a) examining the standard VMAT plan, in which the underdosed volume in the nominal dose distribution (UVN) was generated by subtracting the volumes receiving the prescription doses from PTVs, and (b) plan robustness analysis, in which in addition to the nominal dose distribution, six perturbed dose distributions were created by translating the CT iso‐center in three cardinal directions by the PTV margin. The coldest dose distribution was represented by the minimum of the seven doses in each voxel. The underdosed volume in the coldest dose distribution (UVC) was generated by subtracting the volumes receiving the prescription doses in the coldest dose distribution from the volumes receiving the prescription doses in the nominal dose distribution. UVN and UVC were subsequently examined for spatial association with the locations of LF. The association was tested using the binominal distribution and the Fisher's exact test of independence. We found that of 13 LFs, 11 were associated with UVCs (P = 0.011), while three were associated with UVNs (P = 0.99). We concluded that the possible target underdosage due to patient setup uncertainties appeared to be a more relevant factor associated with LF in VMAT for H&N cancer than the compromised PTV coverage at least for the patients included in this study.
3D Printing of Microstructured and Stretchable Chitosan Hydrogel for Guided Cell Growth
Authors: Wu Qinghua , Maire Marion , Lerouge Sophie , Therriault Daniel , Heuzey Marie‐Claude
Published: May 2017

The ability to produce complex micro‐ or nanostructures from naturally derived hydrogels is significant for biomedical applications. However, precisely controlled architectures of soft hydrogels are difficult to be achieved due to their limited mechanical properties. Despite intensive research, significant challenges persist to fabricate hydrogels with ordered structures and adequate mechanical and biological properties for mimicking native tissues. In this work, a 3D printing technique is proposed to fabricate chitosan hydrogel with highly flexible and organized microfiber networks. The microstructured hydrogel scaffolds are obtained through a neutralization step. The strain at failure of hydrogel filaments can reach up to ≈400% and maximum strength is ≈7.5 MPa. The hydrogel scaffolds feature surface textures that can guide and align cell growth. This approach of tailoring hydrogels opens doors to design and produce 3D tissue constructs with topographical, biological, and mechanical compatibility.
Auxetic Foam‐Based Contact‐Mode Triboelectric Nanogenerator with Highly Sensitive Self‐Powered Strain Sensing Capabilities to Monitor Human Body Movement
Authors: Zhang Steven L. , Lai Ying‐Chih , He Xu , Liu Ruiyuan , Zi Yunlong , Wang Zhong Lin
Published: May 2017

The first contact‐mode triboelectric self‐powered strain sensor using an auxetic polyurethane foam, conductive fabric, and polytetrafluroethylene (PTFE) is fabricated. Utilizing the auxetic properties of the polyurethane foam, the auxetic polyurethane foam would expand into the PTFE when the foam is stretched, causing contact electrification. Due to a larger contact area between the PTFE and the foam as the foam is stretched, this device can serve effectively as a strain sensor. The sensitivity of this method is explored, and this sensor has the highest sensitivity in all triboelectric nanogenerator devices that are used previously as a strain sensor. Different applications of this strain sensor are shown, and this sensor can be used as a human body monitoring system, self‐powered scale to measure weight, and a seat belt to measure body movements inside a car seat.
A Band‐Edge Potential Gradient Heterostructure to Enhance Electron Extraction Efficiency of the Electron Transport Layer in High‐Performance Perovskite Solar Cells
Authors: Hou Yu , Chen Xiao , Yang Shuang , Li Chunzhong , Zhao Huijun , Yang Hua Gui
Published: May 2017

As the key component in efficient perovskite solar cells, the electron transport layer (ETL) can selectively collect photogenerated charge carriers produced in perovskite absorbers and prevent the recombination of carriers at interfaces, thus ensuring a high power conversion efficiency. Compared with the conventional single‐ or dual‐layered ETLs, a gradient heterojunction (GHJ) strategy is more attractive to facilitate charge separation because the potential gradient created at an appropriately structured heterojunction can act as a driving force to regulate the electron transport toward a desired direction. Here, a SnO2/TiO2 GHJ interlayer configuration inside the ETL is reported to simultaneously achieve effective extraction and efficient transport of photoelectrons. With such an interlayer configuration, the GHJs formed at the perovskite/ETL interface act collectively to extract photogenerated electrons from the perovskite layer, while GHJs formed at the boundaries of the interconnected SnO2 and TiO2 networks throughout the entire ETL layer can extract electron from the slow electron mobility TiO2 network to the high electron mobility SnO2 network. Devices based on GHJ ETL exhibit a champion power conversion efficiency of 18.08%, which is significantly higher than that obtained from the compact TiO2 ETL constructed under the comparable conditions.
Tuning Unique Peapod‐Like Co(SxSe1–x)2 Nanoparticles for Efficient Overall Water Splitting
Authors: Fang Ling , Li Wenxiang , Guan Yongxin , Feng Yangyang , Zhang Huijuan , Wang Shilong , Wang Yu
Published: May 2017

The development of efficient electrocatalysts with low cost and earth abundance for overall water splitting is very important in energy conversion. Although many electrocatalysts based on transition metal dichalcogenides have been developed, rational design and controllable synthesis of fine nanostructures with subtle morphologies and sequential chemical compositions related to these materials remains a challenge. This study reports a series of peapod‐like composites with component‐controllable Co(SxSe1–x)2 nanoparticles encapsulated in carbon fibers, which are obtained by using Co(CO3)0.5(OH)·0.11H2O nanowires as a precursor followed by coating carbon fiber and an adjustable sulfuration/selenylation process. Due to its increased exposure of active sites and improved charge and mass transport capability derived from the unique structure and morphology, the Co(SxSe1–x)2 samples display favorable catalytic activities. It is found that Co(S0.71Se0.29)2 exhibits the best hydrogen evolution reaction (HER) performance and Co(S0.22Se0.78)2 shows the highest activity for the oxygen evolution reaction (OER). When using Co(S0.71Se0.29)2 as a cathode and Co(S0.22Se0.78)2 as an anode, it demonstrates a durable activity for overall water splitting to deliver 10 mA cm−2 at a cell voltage of 1.63 V, thus offering an attractive cost‐effective earth abundant material system toward water splitting.
Few‐Layered PtS2 Phototransistor on h‐BN with High Gain
Authors: Li Liang , Wang Weike , Chai Yang , Li Huiqiao , Tian Mingliang , Zhai Tianyou
Published: May 2017

The very recently rediscovered group‐10 transition metal dichalcogenides (TMDs) such as PtS2 and PtSe2, have joined the 2D material family as potentially promising candidates for electronic and optoeletronic applications due to their theoretically high carrier mobility, widely tunable bandgap, and ultrastability. Here, the first exploration of optoelectronic application based on few‐layered PtS2 using h‐BN as substrate is presented. The phototransistor exhibits high responsivity up to 1.56 × 103 A W−1 and detectivity of 2.9 × 1011 Jones. Additionally, an ultrahigh photogain ≈2 × 106 is obtained at a gate voltage Vg = 30 V, one of the highest gain among 2D photodetectors, which is attributed to the existence of trap states. More interestingly, the few‐layered PtS2 phototransistor shows a back gate modulated photocurrent generation mechanism, that is, from the photoconductive effect dominant to photogating effect dominant via tuning the gate voltage from the OFF state to the ON state. Such good properties combined with gate‐controlled photoresponse of PtS2 make it a competitive candidate for future 2D optoelectronic applications.
Multifunctional Liposomes for Image‐Guided Intratumoral Chemo‐Phototherapy
Authors: Miranda Dyego , Carter Kevin , Luo Dandan , Shao Shuai , Geng Jumin , Li Changning , Chitgupi Upendra , Turowski Steven G. , Li Nasi , Atilla‐Gokcumen G. Ekin , Spernyak Joseph A. , Lovell Jonathan F.
Published: May 2017

Intratumoral (IT) drug injections reduce systemic toxicity, but delivered volumes and distribution can be inconsistent. To improve IT delivery paradigms, porphyrin–phospholipid (PoP) liposomes are passively loaded with three hydrophilic cargos: sulforhodamine B, a fluorophore; gadolinium‐gadopentetic acid, a magnetic resonance (MR) agent; and oxaliplatin, a colorectal cancer chemotherapeutic. Liposome composition is optimized so that cargo is retained in serum and storage, but is released in less than 1 min with exposure to near infrared light. Light‐triggered release occurs with PoP‐induced photooxidation of unsaturated lipids and all cargos release concurrently. In subcutaneous murine colorectal tumors, drainage of released cargo is delayed when laser treatment occurs 24 h after IT injection, at doses orders of magnitude lower than systemic ones. Delayed light‐triggering results in substantial tumor shrinkage relative to controls a week following treatment, although regrowth occurs subsequently. MR imaging reveals that over this time frame, pools of liposomes within the tumor migrate to adjacent regions, possibly leading to altered spatial distribution during triggered drug release. Although further characterization of cargo loading and release is required, this proof‐of‐principle study suggests that multimodal theranostic IT delivery approaches hold potential to both guide injections and interpret outcomes, in particular when combined with chemo‐phototherapy.
Switching between Phosphorescence and Fluorescence Controlled by Chiral Self‐Assembly
Authors: Liu Guofeng , Zhao Yanli
Published: May 2017

Helical self‐assembly plays a unique role in regulating the localized excitations of π functional systems, which can also bring highly multi‐scale orders, and show a special effect to tune the energy of electronics, vibration, and rotation of molecules. Due to controllable and dynamic property of chiral self‐assembly, highly ordered and helical assemblies can be obtained to exhibit amplification effect and fascinating photophysical properties in photoluminescence. However, an effective control of singlet‐triplet emissive switching in a unimolecular platform remains a great challenge. Recently, switchable singlet‐triplet emission induced by helical self‐assembly in a unimolecular platform has been developed. By taking advantage of the helical self‐assembly driven by multiple intermolecular hydrogen bonding and strong π‐π stacking interactions, reversible switching between fluorescence and phosphorescence could be efficiently achieved both in N,N‐dimethylformamide/H2O solution and the solid state. The results will inspire the design of other intelligent luminescent materials through chiral self‐assembly and be valuable for interdisciplinary development of supramolecular self‐assembly and related materials science.
Improving Interfacial Charge Recombination in Planar Heterojunction Perovskite Photovoltaics with Small Molecule as Electron Transport Layer
Authors: Wang Ning , Zhao Kexiang , Ding Tao , Liu Wenbo , Ahmed Ali Said , Wang Zongrui , Tian Miaomiao , Sun Xiao Wei , Zhang Qichun
Published: May 2017

Although perovskite solar cells (PSCs) have emerged as a promising alternative to widely used fossil fuels, the involved high‐temperature preparation of metal oxides as a charge transport layer in most state‐of‐the‐art PSCs has been becoming a big stumbling block for future low‐temperature and large‐scale R2R manufacturing process. Such an issue strongly encourages scientists to find new type of materials to replace metal oxides. Except for expensive PC61BM with unmanageable morphology and electrical properties, the past investigation on the development of low‐temperature‐processed and highly efficient electron transport layers (ETLs) has met some mixed success. In order to further enhance the performance of all‐solution‐processed PSCs, we propose a novel n‐type sulfur‐containing small molecule hexaazatrinaphtho[2,3‐c][1,2,5]thiadiazole (HATNT) with high electron mobility up to 1.73 × 10−2 cm2 V−1 s−1 as an ETL in planar heterojunction PSCs. A high power conversion efficiency of 18.1% is achieved, which is fully comparable with the efficiency from the control device fabricated with PC61BM as ETL. This superior performance mainly attributes from more effective suppression of charge recombination at the perovskite/HATNT interface than that between the perovskite and PC61 BM. Moreover, high electron mobility and strong interfacial interaction via SI or SPb bonding should be also positive factors. Significantly, our results undoubtedly enable new guidelines in exploring n‐type organic small molecules for high‐performance PSCs.
CMIP haploinsufficiency in two patients with autism spectrum disorder and co‐occurring gastrointestinal issues
Authors: Luo Minjie , Fan Jinbo , Wenger Tara L. , Harr Margaret H. , Racobaldo Melissa , Mulchandani Surabhi , Dubbs Holly , Zackai Elaine H. , Spinner Nancy B. , Conlin Laura K.
Published: May 2017

Autism spectrum disorder (ASD) is a genetically heterogeneous group of disorders characterized by impairments in social communication and restricted interests. Though some patients with ASD have an identifiable genetic cause, the cause of most ASD remains elusive. Many ASD susceptibility loci have been identified through clinical studies. We report two patients with syndromic ASD and persistent gastrointestinal issues who carry de novo deletions involving the CMIP gene detected by genome‐wide SNP microarray and fluorescence in situ hybridization (FISH) analysis. Patient 1 has a 517 kb deletion within 16q23.2q23.3 including the entire CMIP gene. Patient 2 has a 1.59 Mb deletion within 16q23.2q23.3 that includes partial deletion of CMIP in addition to 12 other genes, none of which have a known connection to ASD or other clinical phenotypes. The deletion of CMIP is rare in general population and was not found among a reference cohort of approximately 12,000 patients studied in our laboratory who underwent SNP array analysis for various indications. A 280 kb de novo deletion containing the first 3 exons of CMIP was reported in one patient who also demonstrated ASD and developmental delay. CMIP has previously been identified as a susceptibility locus for specific language impairment (SLI). It is notable that both patients in this study had significant gastrointestinal issues requiring enteral feedings, which is unusual for patients with ASD, in addition to unusually elevated birth length, further supporting a shared causative gene. These findings suggest that CMIP haploinsufficiency is the likely cause of syndromic ASD in our patients.
Regioselective Metal‐Free C2−H Arylation of Quinoline N‐Oxides with Aryldiazonium Salts/Anilines under Ambient Conditions
Authors: Kumar Rakesh , Kumar Rakesh , Dhiman Ankit Kumar , Sharma Upendra
Published: May 2017

Herein, a base‐promoted direct C2−H arylation of quinoline N‐oxides with aryldiazonium salts under metal‐free conditions is reported. This reaction avoids the need for an oxidant, metal catalyst, or inert atmosphere and proceeds through a highly regioselective C−H bond functionalization to provide a series of C2‐arylated quinoline N‐oxides. Abundantly available amines (anilines and heteroaryl amines) can also be employed as arylating agents through an in situ diazotization process, thereby affording a library of diverse 2‐arylquinoline N‐oxides in moderate‐to‐good yields. The synthesized 2‐arylated quinoline N‐oxides were further converted into C8‐substituted quinolines to demonstrate the applicability of this catalytic approach. A radical pathway is proposed for the C2 arylation, based on a preliminary mechanistic study.
High‐Molecular‐Weight Polynucleotides by Transferase‐Catalyzed Living Chain‐Growth Polycondensation
Authors: Tang Lei , Navarro Luis A. , Chilkoti Ashutosh , Zauscher Stefan
Published: May 2017

We present terminal deoxynucleotidyl transferase‐catalyzed enzymatic polymerization (TcEP) for the template‐free synthesis of high‐molecular‐weight, single‐stranded DNA (ssDNA) and demonstrate that it proceeds by a living chain‐growth polycondensation mechanism. We show that the molecular weight of the reaction products is nearly monodisperse, and can be manipulated by the feed ratio of nucleotide (monomer) to oligonucleotide (initiator), as typically observed for living polymerization reactions. Understanding the synthesis mechanism and the reaction kinetics enables the rational, template‐free synthesis of ssDNA that can be used for a range of biomedical and nanotechnology applications.
Magnetocatalytic Graphene Quantum Dots Janus Micromotors for Bacterial Endotoxin Detection
Authors: Jurado‐Sánchez Beatriz , Pacheco Marta , Rojo Jaime , Escarpa Alberto
Published: May 2017

Magnetocatalytic hybrid Janus micromotors encapsulating phenylboronic acid (PABA) modified graphene quantum dots (GQDs) are described herein as ultrafast sensors for the detection of deadly bacteria endotoxins. A bottom‐up approach was adopted to synthesize an oil‐in‐water emulsion containing the GQDs along with a high loading of platinum and iron oxide nanoparticles on one side of the Janus micromotor body. The two different “active regions” enable highly efficient propulsion in the presence of hydrogen peroxide or magnetic actuation without the addition of a chemical fuel. Fluorescence quenching was observed upon the interaction of GQDs with the target endotoxin (LPS), whereby the PABA tags acted as highly specific recognition receptors of the LPS core polysaccharide region. Such adaptive hybrid operation and highly specific detection hold considerable promise for diverse clinical, agrofood, and biological applications and integration in future lab‐on‐chip technology.
High‐Flux Carbon Molecular Sieve Membranes for Gas Separation
Authors: Richter Hannes , Voss Hartwig , Kaltenborn Nadine , Kämnitz Susanne , Wollbrink Alexander , Feldhoff Armin , Caro Jürgen , Roitsch Stefan , Voigt Ingolf
Published: May 2017

Carbon membranes have great potential for highly selective and cost‐efficient gas separation. Carbon is chemically stable and it is relative cheap. The controlled carbonization of a polymer coating on a porous ceramic support provides a 3D carbon material with molecular sieving permeation performance. The carbonization of the polymer blend gives turbostratic carbon domains of randomly stacked together sp2 hybridized carbon sheets as well as sp3 hybridized amorphous carbon. In the evaluation of the carbon molecular sieve membrane, hydrogen could be separated from propane with a selectivity of 10 000 with a hydrogen permeance of 5 m3(STP)/(m2hbar). Furthermore, by a post‐synthesis oxidative treatment, the permeation fluxes are increased by widening the pores, and the molecular sieve carbon membrane is transformed from a molecular sieve carbon into a selective surface flow carbon membrane with adsorption controlled performance and becomes selective for carbon dioxide.
A Single Spherical Assembly of Protein Amyloid Fibrils Formed by Laser Trapping
Authors: Yuyama Ken‐ichi , Ueda Mariko , Nagao Satoshi , Hirota Shun , Sugiyama Teruki , Masuhara Hiroshi
Published: May 2017

Protein amyloids have received much attention owing to their correlation with serious diseases and to their promising mechanical and optical properties as future materials. Amyloid formation has been conducted by tuning temperature and chemical conditions, so that its nucleation and the following growth are analyzed as ensemble dynamics. A single spherical assembly of amyloid fibrils of cytochrome c domain‐swapped dimer was successfully generated upon laser trapping. The amyloid fibrillar structure was confirmed by fluorescence characterization and electron microscopy. The prepared spheres were further manipulated individually in solution to fabricate a three‐dimensional microstructure and a line pattern. Amyloid formation dynamics and amyloid‐based microstructure fabrication are demonstrated based on direct observation of a single spherical assembly, which foresees a new approach in amyloid studies.
AJIPHASE®: A Highly Efficient Synthetic Method for One‐Pot Peptide Elongation in the Solution Phase by an Fmoc Strategy
Authors: Takahashi Daisuke , Inomata Tatsuji , Fukui Tatsuya
Published: May 2017

We previously reported an efficient peptide synthesis method, AJIPHASE®, that comprises repeated reactions and isolations by precipitation. This method utilizes an anchor molecule with long‐chain alkyl groups as a protecting group for the C‐terminus. To further improve this method, we developed a one‐pot synthesis of a peptide sequence wherein the synthetic intermediates were isolated by solvent extraction instead of precipitation. A branched‐chain anchor molecule was used in the new process, significantly enhancing the solubility of long peptides and the operational efficiency compared with the previous method, which employed precipitation for isolation and a straight‐chain aliphatic group. Another prerequisite for this solvent‐extraction‐based strategy was the use of thiomalic acid and DBU for Fmoc deprotection, which facilitates the removal of byproducts, such as the fulvene adduct.
Corona[5]arenes Accessed by a Macrocycle‐to‐Macrocycle Transformation Route and a One‐Pot Three‐Component Reaction
Authors: Wu Zhi‐Chen , Guo Qing‐Hui , Wang Mei‐Xiang
Published: May 2017

Corona[5]arenes, a novel type of macrocyclic compound that is composed of alternating heteroatoms and para‐arylenes, were synthesized efficiently by two distinct methods. In a macrocycle‐to‐macrocycle transformation approach, S6‐corona[3]arene[3]tetrazine underwent sequential SNAr reactions with HS‐C6H4‐X‐C6H4‐SH (X=S, CH2, CMe2, SO2, and O) to produce the corresponding corona[3]arene[2]tetrazines. Different corona[3]arene[2]tetrazine compounds were also constructed in a straightforward manner by a one‐pot three‐component reaction of HS‐C6H4‐X‐C6H4‐SH (X=S, CH2, CMe2, SO2, and O) with diethyl 2,5‐dimercaptoterephthalate and 2 equiv of 3,6‐dichlorotetrazine under very mild conditions. All corona[5]arenes adopted 1,2,4‐alternate conformational structures in the crystalline state yielding similar nearly regular pentagonal cavities. Both the cavity size and the electronic property of the acquired macrocycles were fine‐tuned by the nature of the bridging element X.
Direct Mechanism of the First Carbon–Carbon Bond Formation in the Methanol‐to‐Hydrocarbons Process
Authors: Wu Xinqiang , Xu Shutao , Zhang Wenna , Huang Jindou , Li Jinzhe , Yu Bowen , Wei Yingxu , Liu Zhongmin
Published: May 2017

In the past two decades, the reaction mechanism of C−C bond formation from either methanol or dimethyl ether (DME) in the methanol‐to‐hydrocarbons (MTH) process has been a highly controversial issue. Described here is the first observation of a surface methyleneoxy analogue, originating from the surface‐activated DME, by in situ solid‐state NMR spectroscopy, a species crucial to the first C−C bond formation in the MTH process. New insights into the first C−C bond formation were provided, thus suggesting DME/methanol activation and direct C−C bond formation by an interesting synergetic mechanism, involving C−H bond breakage and C−C bond coupling during the initial methanol reaction within the chemical environment of the zeolite catalyst.
A Pd@Zeolite Catalyst for Nitroarene Hydrogenation with High Product Selectivity by Sterically Controlled Adsorption in the Zeolite Micropores
Authors: Zhang Jian , Wang Liang , Shao Yi , Wang Yanqin , Gates Bruce C. , Xiao Feng‐Shou
Published: May 2017

The adsorption of molecules on metal nanoparticles can be sterically controlled through the use of zeolite crystals, which enhances the product selectivity in hydrogenations of reactants with more than one reducible group. Key to this success was the fixation of Pd nanoparticles inside Beta zeolite crystals to form a defined structure (Pd@Beta). In the hydrogenation of substituted nitroarenes with multiple reducible groups as a model reaction, the Pd@Beta catalyst exhibited superior selectivity for hydrogenation of the nitro group, outperforming both conventional Pd nanoparticles supported on zeolite crystals and a commercial Pd/C catalyst. The extraordinary selectivity of Pd@Beta was attributed to the sterically selective adsorption of the nitroarenes on the Pd nanoparticles controlled by the zeolite micropores, as elucidated by competitive adsorption and adsorbate displacement tests. Importantly, this strategy is general and was extended to the synthesis of selective Pt and Ru catalysts by fixation inside Beta and mordenite zeolites.
A Smart Flexible Zinc Battery with Cooling Recovery Ability
Authors: Zhao Jingwen , Sonigara Keval K. , Li Jiajia , Zhang Jian , Chen Bingbing , Zhang Jianjun , Soni Saurabh S. , Zhou Xinhong , Cui Guanglei , Chen Liquan
Published: May 2017

Flexible batteries are essential for wearable electronic devices. To meet practical applications, they need to be mechanically robust and stable. However, strong or multiple bending may sever the interfacial contact between electrode and electrolyte, causing capacity fading or even battery failure. Herein we present a new cooling‐recovery concept for flexible batteries, which involves a temperature‐sensitive sol–gel transition behavior of the thermoreversible polymer hydrogel electrolyte. Once a battery has suffered from strong mechanical stresses, a simple cooling process can refresh the electrode–electrolyte interface. The energy‐storage capability can be recovered with a healing efficiency higher than 98 %. It is believed that this study not only offers new valuable insights, but also opens up new perspectives to develop functional wearable devices.
Dynamic Cooperative Glycan Assembly Blocks the Binding of Bacterial Lectins to Epithelial Cells
Authors: Machida Takuya , Novoa Alexandre , Gillon Émilie , Zheng Shuangshuang , Claudinon Julie , Eierhoff Thorsten , Imberty Anne , Römer Winfried , Winssinger Nicolas
Published: May 2017

Pathogens frequently rely on lectins for adhesion and cellular entry into the host. Since these interactions typically result from multimeric binding of lectins to cell‐surface glycans, novel therapeutic strategies are being developed with the use of glycomimetics as competitors of such interactions. Herein we study the benefit of nucleic acid based oligomeric assemblies with PNA–fucose conjugates. We demonstrate that the interactions of a lectin with epithelial cells can be inhibited with conjugates that do not form stable assemblies in solution but benefit from cooperativity between ligand–protein interactions and PNA hybridization to achieve high affinity. A dynamic dimeric assembly fully blocked the binding of the fucose‐binding lectin BambL of Burkholderia ambifaria, a pathogenic bacterium, to epithelial cells with an efficiency of more than 700‐fold compared to l‐fucose.
Exploring Planar‐Chiral Amino Siloxides
Authors: Golz Christopher , Steffen Patricia , Strohmann Carsten
Published: May 2017

We present the synthesis, structure, and exemplary reactivity of siloxides with a planar‐chiral N,N‐dimethylaminomethylferrocene backbone. Several zinc complexes based on the racemic as well as the enantiomerically pure silanol were synthesized in the presence of water and crystallographically characterized, and their behavior in solution was examined. The chiral probe present in this system is a valuable tool for identifying the structure in solution. Furthermore, the zinc siloxides exhibit a comparable reactivity to the corresponding silanols. Therefore, they can be regarded as “masked” silanols, especially when the silanols are preparatively inaccessible.
Correlation between Chiral Modifier Adsorption and Enantioselectivity in Hydrogenation Catalysis
Authors: Ni Yufei , Gordon Alexander D. , Tanicala Florisa , Zaera Francisco
Published: May 2017

Infrared absorption spectroscopy performed in situ at the solid–liquid interface revealed that the adsorption on platinum supported catalysts of 1‐(1‐naphthyl)‐ethylamine, which is used as a chiral modifier in hydrogenation catalysis, occurs through the amine group, not the aromatic ring as is widely believed. Comparisons were performed against a set of related modifier compounds with targeted substitutions to help identify the key moiety involved in the adsorption. It was determined that neither naphthalene‐based modifiers without amine groups nor those with tertiary amine moieties are capable of adsorbing on the metal surface to any significant extent. A direct correlation was also found between the ability of the amines to adsorb on the platinum surface and their performance as chiral modifiers that impart enantioselectivity to the hydrogenation of α‐keto esters such as ethyl pyruvate.
One‐pot carboxylative cyclization of propargylic alcohols and CO2 catalysed by N‐heterocyclic carbene/Ag systems
Authors: Yuan Ye , Xie Yu , Song Dandan , Zeng Cheng , Chaemchuen Somboon , Chen Cheng , Verpoort Francis
Published: May 2017

A series of N‐heterocyclic carbene (NHC)/Ag systems were developed for the carboxylative assembly of propargylic alcohols and carbon dioxide (CO2). With the catalysis of these catalytic systems, a variety of target α‐alkylidene cyclic carbonates could be obtained smoothly under atmospheric CO2 pressure in straightforward one‐pot processes. Particularly, these reactions could be performed without any stoichiometric addition of bases or additives. Further mechanistic investigation reveals that the excellent activities are attributed to the effective activations of CO2 accomplished by the NHCs via the formation of the NHC‐CO2 adducts.
Swelling behavior of poly(n‐butyl acrylate/1,6‐hexane‐diol‐di‐acrylate)/nematic liquid crystalE7 systems: Experimental measurements and modeling by factorial design method
Authors: Dali Youcef Boumédiène , Bouchaour Tewfik , Bouberka Zohra , Bigan Muriel , Maschke Ulrich
Published: May 2017

The swelling process of poly(n‐butyl acrylate/1,6‐hexane‐diol‐di‐acrylate) [Poly(Abu/HDDA)] networks, immersed in a liquid crystalline (LC) solvent, was investigated in order to obtain improved swelling ratio values upon application of an original method using a central composite design. The polymer/LC systems under investigation were elaborated via a photopolymerization/crosslinking phase separation process induced by UV radiation of initial mixtures composed of mono‐ and bifunctional monomers, a photoinitiator, and the low‐molar‐weight nematic LC blend E7. The parameters which strongly impact the swelling behavior of Poly(Abu/HDDA)/E7 systems were identified as temperature and concentration of the bifunctional monomer in the initial photopolymerizable mixture, thus controlling the crosslinking density of the final polymer network. The existence of interactions and synergies between these two parameters were also examined. The quality of the model was verified by a good agreement between experimental results and predicted response. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 45230.
Fabrication of novel polyaniline/flowerlike copper monosulfide composites with enhanced electromagnetic interference shielding effectiveness
Authors: Hu Xiao‐Sai , Shen Yong
Published: May 2017

Novel polyaniline (PANI)/flowerlike CuS composites with improved electromagnetic interference (EMI) shielding effectiveness (SE) were prepared through the in situ polymerization of PANI into the flowerlike CuS microspheres. X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet–visible optical absorption spectroscopy, thermogravimetric analysis, electrical conductivity testing, and EMI SE testing were used to characterize the as‐obtained products. The results reveal that the flowerlike CuS was uniformly coated by a PANI shell. Most importantly, compared with the original CuS and pure PANI, the novel PANI/flowerlike CuS composites exhibited a remarkably enhanced SE. With a thickness of 3 mm, the optimal EMI SE of the PANI–CuS composites reached −45.2 dB at 2.78 GHz, and an improved shielding efficiency below −18 dB was also obtained over the frequency range from 300 kHz to 3 GHz. This suggested that these novel PANI/flowerlike CuS composites have promising applications in the field of shielding materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45232.
Reinterpretation of the mechanical reinforcement of polymer nanocomposites reinforced with cellulose nanorods
Authors: Sapkota Janak , Martinez Garcia Julio Cesar , Lattuada Marco
Published: May 2017

The mechanical reinforcement of nanocomposites containing nanorods‐like fillers such as cellulose nanocrystals (CNCs) is often interpreted by adapting the classical parallel–series model, assuming a simple hyperbolic dependence between the percolation threshold and aspect ratio. However, such assumptions are valid only for nanorods with high aspect ratio and often are misinterpreting the reinforcement obtained at low volume fraction of filler loading. To elucidate this intriguing scenario, we proposed a new approach and validated it by compiling and reinterpreting some of available literature that represent the experimental reinforcement with CNCs. Our approach showed better accuracy, specifically for the cases of CNC nanorods with lower aspect ratio. We conclude that this route permits a more realistic evaluation of the mechanical reinforcement, where a physical parameter accounting the polymer filler association is introduced. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45254.
Investigation on the interaction of collagen molecules in solution with different acetic acid concentrations
Authors: Yang Huan , Deng Yi , Xu Songcheng , Liu Wentao , Li Guoying
Published: May 2017

Collagen solutions in the presence of 0.1–2.0M acetic acid (AA) were investigated to understand the interaction between collagen molecules and an acidic solvent. Fluorescence measurements of pyrene showed that the critical aggregation concentration (CAC) of collagen increased from 0.518 to 1.581 mg/mL for AA concentrations ranging from 0.1 to 2.0M, indicating that the aggregated state of collagen molecules was associated with AA concentration. The size of the collagen aggregates, determined by dynamic light scattering, demonstrated that their disaggregation was enhanced with increasing electrostatic repulsion between the collagen chains. The variations in the intrinsic viscosity and Huggins coefficient depended on the molecular interaction among the collagen molecules. Furthermore, the increased AA concentration has a different influence on the rigidity of collagen molecules above and below the CAC. This observation was manifested by the changes in the morphology of collagen molecules observed by atomic force microscopy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45255.
Office waste paper as cellulose nanocrystal source
Authors: Orue Ander , Santamaria‐Echart Arantzazu , Eceiza Arantxa , Peña‐Rodriguez Cristina , Arbelaiz Aitor
Published: May 2017

Cellulose nanocrystals (CNC) are isolated from office waste paper using an alkali solution and a subsequent acid hydrolysis process. The Fourier transform infrared spectroscopy and X‐ray diffraction (XRD) results demonstrate that ink and fillers used in the papermaking industry are almost totally removed after alkali treatments. The XRD results show that CNCs obtained after 2 wt % NaOH solution treatment and a subsequent hydrolysis process exhibit only a cellulose I crystalline structure, and the crystallinity index value increases around 42% with respect to initial office waste paper. Nevertheless, CNCs obtained after 7.5 wt % NaOH solution treatment and a subsequent acid hydrolysis process show a mixture of cellulose I and cellulose II polymorphs. The thermal analysis shows that the CNCs obtained after 7.5 wt % NaOH solution treatment and a subsequent acid hydrolysis process are thermally less stable than other samples, suggesting that the cellulose chains could depolymerize into low molecular weight sugar compounds. Even though the atomic force microscopy images confirm the presence of CNCs, the optical images show that some cellulose microfibers still maintain their structure. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45257.
Effects of poly(propylene carbonate) additive prepared from carbon dioxide on the tensile properties of polypropylene
Authors: Takubo Etsuko , Hiejima Yusuke , Nishioka Kiyoshi , Nitta Koh‐hei
Published: May 2017

We investigated the effect of a rubbery poly(propylene carbonate) (PPC) additive on the tensile properties of isotactic polypropylene (iPP). PPC materials were produced from carbon dioxide gas. Although the elongation of iPP was reduced at higher elongation speeds, PPC addition improved the elongation at break at higher elongation speeds. iPP/PPC blends showed a high drawability while maintaining a high stress level. The failure mechanisms at high elongation speeds were different between the iPP and iPP/PPC samples. Craze‐like voids appeared along the stretching direction for pure iPP, whereas the PPC additive yielded craze‐like voids that were perpendicular to the stretching direction. The addition of PPC doped with carbon nanodots enhanced the yield toughness of iPP at high elongation speeds. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45266.
Dual‐fluorophore Raspberry‐like Nanohybrids for Ratiometric pH Sensing
Authors: Acquah Isaac , Roh Jinkyu , Ahn Dong June
Published: May 2017

We report on the development of raspberry‐like silica structures formed by the adsorption of 8‐hydroxypyrene‐1,3,6‐trisulfonate (HPTS)@silica nanoparticles (NPs) on rhodamine B isothiocyanate (RBTIC)@silica NPs for ratiometric fluorescence‐based pH sensing. To overcome the well‐known problem of dye leaching which occurs during encapsulation of anionic HPTS dye in silica NPs, we utilized a polyelectrolyte‐assisted incorporation of the anionic HPTS. The morphological and optical characterization of the as‐synthesized dye‐doped NPs and the resulting nanohybrids were carried out. The pH‐sensitive dye, HPTS, incorporated in the HPTS‐doped silica NPs provided a pH‐dependent fluorescence response while the RBITC‐doped silica provided the reference signal for ratiometric sensing. We evaluated the effectiveness of the nanohybrids for pH sensing; the ratio of the fluorescence emission intensity at 510 nm and 583 nm at excitation wavelengths of 454 nm and 555 nm, respectively. The results showed a dynamic response in the acidic pH range. With this approach, nanohybrids containing different dyes or receptors could be developed for multifunctioning and multiplexing applications.
C/D‐box snoRNAs form methylating and non‐methylating ribonucleoprotein complexes: Old dogs show new tricks
Authors: Falaleeva Marina , Welden Justin R. , Duncan Marilyn J. , Stamm Stefan
Published: May 2017

C/D box snoRNAs (SNORDs) are an abundantly expressed class of short, non‐coding RNAs that have been long known to perform 2′‐O‐methylation of rRNAs. However, approximately half of human SNORDs have no predictable rRNA targets, and numerous SNORDs have been associated with diseases that show no defects in rRNAs, among them Prader‐Willi syndrome, Duplication 15q syndrome and cancer. This apparent discrepancy has been addressed by recent studies showing that SNORDs can act to regulate pre‐mRNA alternative splicing, mRNA abundance, activate enzymes, and be processed into shorter ncRNAs resembling miRNAs and piRNAs. Furthermore, recent biochemical studies have shown that a given SNORD can form both methylating and non‐methylating ribonucleoprotein complexes, providing an indication of the likely physical basis for such diverse new functions. Thus, SNORDs are more structurally and functionally diverse than previously thought, and their role in gene expression is under‐appreciated. The action of SNORDs in non‐methylating complexes can be substituted with oligonucleotides, allowing devising therapies for diseases like Prader‐Willi syndrome.
A critical evaluation of the current “p‐value controversy”
Authors: Wellek Stefan
Published: May 2017

This article has been triggered by the initiative launched in March 2016 by the Board of Directors of the American Statistical Association (ASA) to counteract the currentp‐value focus of statistical research practices that allegedly “have contributed to a reproducibility crisis in science.” It is pointed out that in the very wide field of statistics applied to medicine, many of the problems raised in the ASA statement are not as severe as in the areas the authors may have primarily in mind, although several of them are well‐known experts in biostatistics and epidemiology. This is mainly due to the fact that a large proportion of medical research falls under the realm of a well developed body of regulatory rules banning the most frequently occurring misuses ofp‐values. Furthermore, it is argued that reducing the statistical hypotheses tests nowadays available to the class of procedures based onp‐values calculated under a traditional one‐point null hypothesis amounts to ignoring important developments having taken place and going on within the statistical sciences. Although hypotheses testing is still an indispensable part of the statistical methodology required in medical and other areas of empirical research, there is a large repertoire of methods based on different paradigms of inference that provide ample options for supplementing and enhancing the methods of data analysis blamed in the ASA statement for causing a crisis.
Polysome profiling of mAb producing CHO cell lines links translational control of cell proliferation and recombinant mRNA loading onto ribosomes with global and recombinant protein synthesis
Authors: Godfrey Charlotte L. , Mead Emma J. , Daramola Olalekan , Dunn Sarah , Hatton Diane , Field Ray , Pettman Gary , Smales C. Mark
Published: May 2017

mRNA translation is a key process determining growth, proliferation and duration of a Chinese hamster ovary (CHO) cell culture and influences recombinant protein synthesis rate. During bioprocessing, CHO cells can experience stresses leading to reprogramming of translation and decreased global protein synthesis. Here we apply polysome profiling to determine reprogramming and translational capabilities in host and recombinant monoclonal antibody‐producing (mAb) CHO cell lines during batch culture. Recombinant cell lines with the fastest cell specific growth rates were those with the highest global translational efficiency. However, total ribosomal capacity, determined from polysome profiles, did not relate to the fastest growing or highest producing mAb cell line, suggesting it is the ability to utilise available machinery that determines protein synthetic capacity. Cell lines with higher cell specific productivities tended to have elevated recombinant heavy chain transcript copy numbers, localised to the translationally active heavy polysomes. The highest titre cell line was that which sustained recombinant protein synthesis and maintained high recombinant transcript copy numbers in polysomes. Investigation of specific endogenous transcripts revealed a number that maintained or reprogrammed into heavy polysomes, identifying targets for potential cell engineering or those with 5' untranslated regions that might be utilised to enhance recombinant transcript translation.