bluuebunny/crossref_metadata_2025 huggingface dataset:
Bifunctional Hybrid Ni/Ni2P Nanoparticles Encapsulated by Graphitic Carbon Supported with N, S Modified 3D Carbon Framework for Highly Efficient Overall Water Splitting
Authors: Sun Yiqiang , Zhang Tao , Li Xinyang , Bai Yu , Lyu Xianjun , Liu Guangqiang , Cai Weiping , Li Yue
Published: June 2018

The novel hybrid Ni/Ni2P nanoparticles with graphitic carbon coating supported by 3D N, S dual modified binder‐free macroporous carbon framework (Ni/Ni2P@3DNSC) are reported as an efficient bifunctional electrocatalysts for the production of hydrogen and oxygen. The obtained Ni/Ni2P@3DNSC electrode exhibits an excellent catalytic activity with a low overpotential of 231 mV for oxygen evolution reaction (OER) and 92 mV for hydrogen evolution reaction (HER) due to the strong coupled interface of Ni and Ni2P, synergistic effects between the hybrid Ni/Ni2P core and the graphitic carbon shell, the unique porous structure, and the heteroatoms doped effect. When both are used as cathode and anode, only a low cell voltage of 1.55 V is needed to achieve the current density of 10 mA cm−2. This work demonstrates a new avenue for the development of bifunctional nonprecious electrocatalysts for the sustainable energy utilization.
Poly(ethylene terephthalate) Fibers with a Thin Layer of Click‐Based Microporous Organic Network: Enhanced Capture Performance toward PM2.5
Authors: Kang Chang Wan , Ko Yoon‐Joo , Lee Sang Moon , Kim Hae Jin , Son Seung Uk
Published: June 2018

This work shows that the adsorptive performance of fibrous membrane can be enhanced by microporous organic network (MON) chemistry. Copper species are introduced into the surface of poly(ethylene terephthalate) (PET) fibers through electroless deposition. Through the Cu2O‐catalyzed click reactions of tetra(4‐ethynylphenyl)methane with 1,4‐diazidobenzene, click‐based MON (C‐MON) layers are formed on the PET@Cu@Cu2O. Etching of copper species results in the formation of PET@C‐MON membranes that show enhanced removal performance by up to 13.3 times for particulate matters with smaller sizes than 2.5 µm (PM2.5), compared with pristine PET fibers.
Polydopamine–Copper Hybrid Films as Source and Drain for Oxide Semiconductor Field‐Effect Transistors
Authors: Namgung Seok Daniel , Lee Jaehun , Sung Taehoon , Kim Hyung‐Jun , Cho Ah‐Jin , Koh Sungjoon , An Junghyun , Choe Ik Rang , Nam Ki Tae , Kwon Jang‐Yeon
Published: June 2018

Oxide semiconductors are one of the key components for flexible and transparent electronics, but their use has been limited by the work function of contact materials. Carbon‐based materials are strong candidates for flexible transparent electrodes, and nitrogen‐doped carbon materials have been specifically investigated due to the controllability of their work function. Of the many methods to dop nitrogen, the pyrolysis of biomolecules is a particular focus since it is a simple, inexpensive process that yields a high atomic percent of nitrogen. Polydopamine (pDop), which is inspired by adhesive proteins in mussels, has been suggested for use as a precursor for pyrolysis, and the pyrolyzed pDop–Cu hybrid film shows the lowest resistivity (1.4 × 10−4 Ω cm) in pyrolyzed carbon so far, for which copper chelation is attributed to reduction in resistivity. The pyrolyzed film also shows a transparency of 84%, and it is stable in cyclic bending tests up to 105 cycles. The films are further applied to the source and drain of a field‐effect transistor, and the devices achieve a high performance that is comparable to that from molybdenum contacted device, with the work function ranging from 4.51 to 4.31 eV.
High‐Mobility, Solution‐Processed Organic Field‐Effect Transistors from C8‐BTBT:Polystyrene Blends
Authors: Haase Katherina , Teixeira da Rocha Cecilia , Hauenstein Christoph , Zheng Yichu , Hambsch Mike , Mannsfeld Stefan C. B.
Published: June 2018

Organic field‐effect transistors based on aligned small molecule semiconductors have shown high charge carrier mobilities in excess of 10 cm2 V−1 s−1. This makes them a viable alternative to amorphous inorganic semiconductors especially if a high reproducibility can be achieved. Here, the optimization of high mobility organic field‐effect transistors based on the organic semiconductor 2,7‐dioctyl[1]benzothieno[3,2‐b] benzothiophene (C8‐BTBT) via the addition of a polymer additive to the printing solution is reported. Specifically, films and devices are compared based on solutions of the neat semiconductor and the blend with polystyrene and shear‐coated devices with excellent device characteristics and gate‐voltage‐independent mobility values reaching 12 cm2 V−1 s−1 are shown, which are the highest reported values for C8‐BTBT‐based films prepared by a scalable, solution‐based process.
p53 molecular approach to diagnosis and treatment of esophageal squamous cell carcinoma
Authors: Shimada Hideaki
Published: June 2018

We reviewed our research concerning p53 molecules in esophageal squamous cell carcinoma by focusing on the p53 molecular diagnosis and treatment of esophageal squamous cell carcinoma. First, we developed diagnostic tools to analyze serum p53 autoantibodies to detect esophageal squamous cell carcinoma. Positive rate was around 25% to 30% in all patients and around 20% even in stage I patients. Presence of serum p53 antibodies was significantly associated with overexpression of p53 protein in tumor cells. Seropositive patients were more likely than seronegative patients to be resistant to chemotherapy. Monitoring of the titer of serum p53 autoantibodies was useful in predicting patients at high risk of recurrence and/or treatment response. Second, using Ad5CMV‐p53 for 10 patients with advanced esophageal squamous cell carcinoma, we carried out a phase I/II study of adenoviral‐mediated p53 gene therapy. Although no complete response was observed, local tumor was stabilized in nine patients. No serious adverse events related to Ad5CMV‐p53 were observed in these patients. One patient survived for over 5 years after the start of p53 gene therapy. Intratumoral injection of Ad5CMV‐p53 is therefore safe, feasible, and biologically active when given in multiple doses to patients with esophageal squamous cell carcinoma. Our observations from these clinical studies indicate that p53 is a useful molecular target both in the diagnosis and in the treatment of esophageal squamous cell carcinoma.
A late Cretaceous fagalean inflorescence preserved in amber from New Jersey
Authors: Gandolfo Maria A. , Nixon Kevin C. , Crepet William L. , Grimaldi David A.
Published: June 2018

Premise of The Study

An inflorescence with three pistillate flowers in amber from the early Upper Cretaceous (Turonian, ~90–94 million years ago) of central New Jersey represents the oldest known flowers with features present in an early stem complex of the Fagales. The inflorescence has characteristics of Nothofagaceae, but also has strikingly distinct characters that suggest it is intermediate between Nothofagus and other Fagales. This intermediacy is consistent with its northern hemisphere distribution.

Methods

We investigated this new fossil by comparing it with extant and fossil members of the Fagales using light microscopy and nano‐computed tomography. In addition, for exploring its relationships, we mapped the morphological characters onto a widely accepted molecular‐based tree of modern basal Fagales using standard methods of character optimization.

Key Results

The phylogenetic position of the fossil inflorescence can be unequivocally determined by the presence of unique features, singly and in combination, that are found only in “basal” members of Fagales. The fossil adds critical information on the features of the early stem Fagales, evolution of the cupule in Nothofagaceae and Fagaceae, and a reasonable biogeographic hypothesis for the differentiation of southern (e.g., Nothofagaceae) and northern hemisphere Fagales.

Conclusions

This new fossil provides insight into the early evolution of Fagales and suggests that early stem Fagales that had not yet differentiated into modern families were present in the Late Cretaceous of North America. Based on available evidence, the fossil is best interpreted as an early stem member of the Fagales, with features that suggest a transition from a more generalized Nothofagus‐like fagalean ancestor with some unique presumably plesiomorphic features. The presence of an enlarged perianth and flexuous styles also suggests the possibility of insect pollination, which has been lost in all Fagales with the exception of some members of subfamily Castaneoideae in Fagaceae sensu stricto (which otherwise are very different from this fossil). The poorly developed, bract‐like cupule valves of the fossil can be interpreted as primitive (i.e., incipient) or as reduced from more developed cupules that are found in most modern Fagaceae and Nothofagaceae.
Role of Toll‐like receptor 9 signaling on activation of nasal polyp–derived fibroblasts and its association with nasal polypogenesis
Authors: Park Soo Kyoung , Jin Soung Yong , Yeon Sun Hee , Lee Sung Bok , Xu Jun , Yoon Young Hoon , Rha Ki Sang , Kim Yong Min
Published: June 2018

Background

Nasal polyposis is characterized by persistent inflammation and remodeling in sinonasal mucosa. Toll‐like receptor 9 (TLR9) is a DNA receptor of the innate immune system that plays a pivotal role in fibrosis and inflammatory responses. The aim of this study is to explore the expression, activity, and potential pathogenic role of TLR9 signaling in tissue remodeling in nasal polyp–derived fibroblasts (NPDFs).

Methods

Fibrotic and inflammatory responses elicited by type A CpG oligonucleotides were examined in the NPDFs by a combination of real‐time quantitative polymerase chain reaction, Western blot analysis, enzyme‐linked immunosorbent assay, and immunofluorescence staining. For these experiments, the NPDFs were stimulated with different TLR9 agonists (CpG A and B) and blocked with inhibitors (MyD88 inhibitor and chloroquine).

Results

TLR9 expression was significantly higher in nasal polyposis (NP) tissues compared to control or chronic rhinosinusitis (CRS) mucosa. In the NPDFs, TLR9 showed intracellular localization and expression of TLR9 was increased after treatment with CpG A. CpG A increased production of α‐smooth muscle actin (α‐SMA), fibronectin, and matrix metalloproteinases (MMPs) (MMP1, MMP2, and MMP9) in the NPDFs, while MyD88 inhibitor and chloroquine, which are known to block the TLR9 signaling pathway, inhibited their production. CpG A also produced type I interferons (IFN‐α and IFN‐β), which were inhibited by MyD88 inhibitor.

Conclusion

Our data indicates that CpG A–induced fibroblast activation and cytokine production were mediated via TLR9 stimulation in NPDFs. Disrupting this process with an inhibitor targeting TLR9 or its downstream signaling pathways could represent a novel approach to CRS with NP (CRSwNP) therapy.
Rational Synthesis of Antiaromatic 5,15‐Dioxaporphyrin and Oxidation into β,β‐Linked Dimers
Authors: Nishiyama Akihide , Fukuda Masaya , Mori Shigeki , Furukawa Ko , Fliegl Heike , Furuta Hiroyuki , Shimizu Soji
Published: June 2018

5,15‐Dioxaporphyrin was synthesized for the first time by a nucleophilic aromatic substitution reaction of a nickel bis(α,α′‐dibromodipyrrin) complex with benzaldoxime, followed by an intramolecular annulation of the α‐hydroxy‐substituted intermediate. This unprecedented molecule is a 20π‐electron antiaromatic system, in terms of Hückel's rule of aromaticity, because lone pair electrons of oxygen atoms are incorporated into the 18π‐electron conjugated system of the porphyrin. A theoretical analysis based on the gauge‐including magnetically induced current method confirmed its antiaromaticity and a dominant inner ring pathway for the ring current. The unique reactivity of 5,15‐dioxaporphyrin forming a β,β‐linked dimer upon oxidation was also revealed.
Coating Polymeric Carbon Nitride Photoanodes on Conductive Y:ZnO Nanorod Arrays for Overall Water Splitting
Authors: Fang Yuanxing , Xu Yuntao , Li Xiaochun , Ma Yiwen , Wang Xinchen
Published: June 2018

Polymeric carbon nitride (PCN) photosensitizers are proposed replacements for their inorganic counterparts in solar‐to‐fuel conversion via photoelectrochemical water splitting. However, intense charge recombination, primarily because of surface defects, limits the use of PCN in PEC systems. Now, photoanodes are designed by coating PCN films onto highly conductive yttrium‐doped zinc oxide (Y:ZnO) nanorods (NRs) serving as charge collectors. The generation of charge carriers can therefore be promoted by this type II alignment. The charge collectors would be kept nearby for charge separation and transport to be used in the interfacial redox reactions. The photocurrent density of the polymer electrode is improved to 0.4 mA cm−2 at 1.23 V vs. the reversible hydrogen electrode in a Na2SO4 electrolyte solution under AM 1.5 illumination. The result reveals a more than 50‐fold enhancement over the PCN films achieved by powder; the efficiency can be preserved at 95 % for 160 minutes.
Recently Detected Drinking Water Contaminants: GenX and Other Per‐ and Polyfluoroalkyl Ether Acids
Authors: Hopkins Zachary R. , Sun Mei , DeWitt Jamie C. , Knappe Detlef R.U.
Published: June 2018

For several decades, a common processing aid in the production of fluoropolymers was the ammonium salt of perfluorooctanoic acid (PFOA). Because PFOA is persistent, bioaccumulative, and toxic, its production and use are being phased out in the United States. In 2009, the US Environmental Protection Agency stipulated conditions for the manufacture and commercial use of GenX, a PFOA replacement. While GenX is produced for commercial purposes, the acid form of GenX is also generated as a byproduct during the production of fluoromonomers. The discovery of high concentrations of GenX and related perfluoroalkyl ether acids (PFEAs) in the Cape Fear River and in finished drinking water of more than 200,000 North Carolina residents required quick action by researchers, regulators, public health officials, commercial laboratories, drinking water providers, and consulting engineers. Information about sources and toxicity of GenX as well as an analytical method for the detection of GenX and eight related PFEAs is presented. GenX/PFEA occurrence in water and GenX/PFEA removal by different drinking water treatment processes are also discussed.
Protein Interactions in the T7 DNA Replisome Facilitate DNA Damage Bypass
Authors: Zou Zhenyu , Chen Ze , Xue Qizhen , Xu Ying , Xiong Jingyuan , Yang Ping , Le Shuai , Zhang Huidong
Published: June 2018

The DNA replisome inevitably encounters DNA damage during DNA replication. The T7 DNA replisome contains a DNA polymerase (gp5), the processivity factor thioredoxin (trx), a helicase‐primase (gp4), and a ssDNA‐binding protein (gp2.5). T7 protein interactions mediate this DNA replication. However, whether the protein interactions could promote DNA damage bypass is still little addressed. In this study, we investigated strand‐displacement DNA synthesis past 8‐oxoG or O6‐MeG lesions at the synthetic DNA fork by the T7 DNA replisome. DNA damage does not obviously affect the binding affinities between helicase, polymerase, and DNA fork. Relative to unmodified G, both 8‐oxoG and O6‐MeG—as well as GC‐rich template sequence clusters—inhibit strand‐displacement DNA synthesis and produce partial extension products. Relative to the gp4 ΔC‐tail, gp4 promotes DNA damage bypass. The presence of gp2.5 also promotes it. Thus, the interactions of polymerase with helicase and ssDNA‐binding protein facilitate DNA damage bypass. Accessory proteins in other complicated DNA replisomes also facilitate bypassing DNA damage in similar manner. This work provides new mechanistic information relating to DNA damage bypass by the DNA replisome.
Improvement of SNAr Reaction Rate by an Electron‐Withdrawing Group in the Crosslinking of DNA Cytosine‐5 Methyltransferase by a Covalent Oligodeoxyribonucleotide Inhibitor
Authors: Kasai Yukiko , Sato Kousuke , Utsumi Shohei , Ichikawa Satoshi
Published: June 2018

DNA cytosine 5‐methyltransferase (DNMT) catalyzes methylation at the C5 position of the cytosine residues in the CpG sequence. Aberrant DNA methylation patterns are found in cancer cells. Therefore, inhibition of human DNMT is an effective strategy for treating various cancers. The inhibitors of DNMT have an electron‐deficient nucleobase because this group facilitates attack by the catalytic Cys residue in DNMTs. Recently, we reported the synthesis and properties of mechanism‐based modified nucleosides, 2‐amino‐4‐halopyridine‐C‐nucleosides (dXP), as inhibitors of DNMT. To develop a more efficient inhibitor of DNMT for oligonucleotide therapeutics, oligodeoxyribonucleotides (ODNs) containing other nucleoside analogues, which react more quickly with DNMT, are needed. Herein, we describe the design, synthesis, and evaluation of the properties of 2‐amino‐3‐cyano‐4‐halopyridine‐C‐nucleosides (dXPCN) and ODNs containing dXPCN, as more reactive inhibitors of DNMTs. Nucleophilic aromatic substitution (SNAr) of the designed nucleosides, dXPCN, was faster than that of dXP, and the ODN containing dXPCN effectively formed a complex with DNMTs. This study suggests that the incorporation of an electron‐withdrawing group would be an effective method to increase reactivity toward the nucleophile of the DNMTs, while maintaining high specificity.
Excimer laser in contrast for the treatment of acute MI caused by thrombosis of underexpanded stent
Authors: Tai Zaheed
Published: June 2018

Key Clinical Message

The use of excimer laser with contrast for treating an underexpanded stent in the setting of subacute stent thrombosis and hemodynamic instability is described. The patients presented with acute coronary syndromes and cardiogenic shock resulting from stent thrombosis of underexpanded stents. The stents were recalcitrant to aggressive balloon dilation and in the setting of an acute myocardial infarction; rotational atherectomy is a relative contraindication. The use of concurrent contrast during laser atherectomy resulted in plaque modification and subsequent stent expansion.
Prenatal diagnosis of Pallister‐Killian syndrome in one twin
Authors: Li Lin , Huang Linhuan , Huang Xuan , Lin Shaobin , He Zhiming , Fang Qun
Published: June 2018

Key Clinical Message

Pallister‐Killian syndrome (PKS) is often incidentally diagnosed prenatally due to ultrasound abnormalities or advanced maternal age. Severely shortened limbs could be the most outstanding abnormal observation in a fetus with PKS. PKS can be detected with the highest mosaic ratio by chromosomal microarray analysis (CMA) on uncultured amniocytes prenatally.
Homogeneous Catalytic Reduction of CO2 with Silicon‐Hydrides, State of the Art
Authors: Fernández‐Alvarez Francisco J. , Oro Luis A.
Published: June 2018

During recent years, the catalytic transformation of CO2 using silicon‐hydrides as reductants has emerged as a promising methodology that allows the selective reduction of CO2 to the formate, formaldehyde, methoxide or methane level under mild reaction conditions. Moreover, some catalysts have been employed for the formylation and/or methylation of the N−H bonds of secondary and/or primary amines by their reaction with CO2 and hydrosilanes. This work summarizes the different catalytic systems that have shown to be efficient for the above‐mentioned reactions. Furthermore, a brief description of the reactions performance and the conditions employed in each case is included.
Self‐Synthesizing Models of Helical Proteins Based on Aromatic Disulfide Chemistry
Authors: Wołczański Grzegorz , Cal Marta , Waliczek Mateusz , Lisowski Marek , Stefanowicz Piotr
Published: June 2018

A new method of synthesis of peptide conjugates with aromatic moieties substituted with two sulfhydryl groups at 1,3‐positions is proposed. Amphiphilic peptides derivatized in such a way under oxidative conditions spontaneously form cyclic, covalent trimers and tetramers dominated by α‐helical conformations. The tendency to form tri‐ or tetrahelical bundles depends on sequences of the peptides and on the oxidation conditions, pH, and additives.
Polyphenolic‐Chemistry‐Enabled, Mechanically Robust, Flame Resistant and Superhydrophobic Membrane for Separation of Mixed Surfactant‐Stabilized Emulsions
Authors: Ye Xiaoxia , Ke Le , Wang Yaping , Gao Kaiyang , Cui Yiwen , Wang Xiaoling , Huang Xin , Shi Bi
Published: June 2018

Superhydrophobic materials hold great promise in emulsion separation, but they have inherent mechanical weakness and are ineffective to separate mixed surfactant‐stabilized emulsions. Herein, we combined the adhesion ability of polyphenol–Fe3+ bis‐complexes with the high mechanical strength of carbon nanotubes (CNTs) to construct a mechanically robust and superhydrophobic coating on a collagen fiber membrane (CFM). We demonstrated that both CNTs and polyphenolic complexes competed with the surfactants adsorbed onto the emulsion droplets, serving as efficient demulsifiers to various mixed surfactant‐stabilized emulsions. CFM has a 3D fibrous structure and a high limiting oxygen index, which provides high flux and flame resistance. The as‐prepared superhydrophobic membrane can separate diverse anionic/nonionic and cationic/nonionic surfactant‐stabilized micro‐ and nanoemulsions under gravity, with a separation efficiency and flux up to 99.999 % and 1695 L m−2 h−1, respectively. The membranes also retained the emulsion separation ability after sandpaper abrasion. These features demonstrate a practical technology for emulsion separation.
Azabora[5]helicene Charge‐Transfer Dyes Show Efficient and Spectrally Variable Circularly Polarized Luminescence
Authors: Domínguez Zoe , López‐Rodríguez Rocío , Álvarez Eleuterio , Abbate Sergio , Longhi Giovanna , Pischel Uwe , Ros Abel
Published: June 2018

Three helicenes based on a borylated arylisoquinoline skeleton have been prepared in their enantiopure forms and characterized with respect to their photophysical properties, including the use of chiroptical spectroscopies. The dyes show varying charge‐transfer characteristics and efficient emission (quantum yields between 0.13 and 0.30, in toluene), which is governed by the electron‐donor substitution (p‐MeO‐phenyl, p‐Me2N‐phenyl) at the helicene. Marked differences in the emission wavelength and Stokes shift are observed, with the dimethylamino‐substituted derivative emitting most red‐shifted (maximum at ca. 590 nm) and displaying the highest Stokes shift (ca. 6000 cm−1) in toluene. The helicenes show electronic circular dichroism (ECD) and significant circularly polarized luminescence (CPL) with dissymmetry factors of up to 3.5×10−3. The sign of the ECD band corresponding to the first transition and of the CPL spectrum depend sensibly on the electron‐donor substitution.
Oxo‐Functionalized Graphene: A Versatile Precursor for Alkylated Graphene Sheets by Reductive Functionalization
Authors: Halbig Christian E. , Martin Oliver , Hauke Frank , Eigler Siegfried , Hirsch Andreas
Published: June 2018

Controlled covalent functionalization of graphene remains a challenging task owing to the heterogeneous nature of materials. Functionalization approaches for graphene either lack in quantifying the degree of functionalization or they do not discriminate between covalent and non‐covalent functionalization. Here, graphite is oxidized and exfoliated in a three‐step procedure and subsequently reduced and functionalized by hexylation. Although Raman spectroscopy is powerful to determine the degree of in‐plane lattice defects (θLD) and functionalization (θFD), the method fails at detecting introduced hexyl groups at a concentration of about 0.03 %, next to the pre‐existing in‐plane lattice defects of 0.7 %. However, sensitive thermogravimetric analysis coupled with gas chromatography and mass spectrometry (TGA‐GC/MS) can prove the hexylation reaction. The efficiency of functionalization is comparable to reductive functionalization of pristine chemical vapor deposition (CVD)‐graphene and bulk graphite.
Thiazoloisoindigo: A Building Block that Merges the Merits of Thienoisoindigo and Diazaisoindigo for Conjugated Polymers
Authors: Li Chenchen , Un Hio‐Ieng , Peng Jiawei , Cai Mian , Wang Xiao , Wang Jieyu , Lan Zhenggang , Pei Jian , Wan Xiaobo
Published: June 2018

Invited for the cover of this issue is the group of Xiao Wang and Xiaobo Wan at the Chinese Academy of Sciences and Jian Pei at the Peking University. The image depicts thiazoloisoindigo as a novel building block that possesses the advantages of both thienoisoindigo (red dragon) and diazaisoindigo (blue dragon). Read the full text of the article at 10.1002/chem.201801432.
Catalyst‐ and Reagent‐Free Electrochemical Azole C−H Amination
Authors: Qiu Youai , Struwe Julia , Meyer Tjark H. , Oliveira João C. A. , Ackermann Lutz
Published: June 2018

Catalyst‐ and chemical oxidant‐free electrochemical azole C−H aminations were accomplished via cross‐dehydrogenative C−H/N−H functionalization. The catalyst‐free electrochemical C−H amination proved feasible on azoles with high levels of efficacy and selectivity, avoiding the use of stoichiometric oxidants under ambient conditions. Likewise, the C(sp3)−H nitrogenation proved viable under otherwise identical conditions. The dehydrogenative C−H amination featured ample scope, including cyclic and acyclic aliphatic amines as well as anilines, and employed sustainable electricity as the sole oxidant.
Existing Self‐Replicators Can Direct the Emergence of New Ones
Authors: Altay Yigit , Altay Meniz , Otto Sijbren
Published: June 2018

The study of the interplay between different self‐replicating molecules constitutes an important new phase in the synthesis of life and in unravelling the origin of life. Here we show how existing replicators can direct the nature of a newly formed replicator. Starting from the same building block, 6‐ring replicators formed when the mixture was exposed to pre‐existing 6‐membered replicators, while pre‐formed 8‐membered replicators funneled the building block into 8‐ring replicators. Not only ring size, but also the mode of assembly of the rings into stacks was inherited from the pre‐existing replicators. These results show that the nature of self‐replicating molecules can be strongly influenced by the interplay between different self‐replicators, overriding preferences innate to the structure of the building block.
In Situ Generation of Oxazole Ylide and Interception with Sulfonamide: Construction of Amidines Using Two Diazo Molecules
Authors: Chen Jijun , Long Wenhao , Zhao Yanwei , Li Haiyan , Zheng Yonggao , Lian Pengcheng , Wan Xiaobing
Published: June 2018

A novel generation of oxazole ylide and interception with sulfonamide have been well developed to construct fully substituted amidines. This copper‐catalyzed four‐component reaction incorporates two diazo molecules to target amidines and shows broad substrate scope, excellent functional groups tolerance and good to excellent yields.
Cover Picture: Anionic Copolymerization of Carbonyl Sulfide with Epoxides via Alkali Metal Alkoxides (Chin. J. Chem. 7/2018)
Authors: Zhang Cheng‐Jian , Yang Jia‐Liang , Hu Lan‐Fang , Zhang Xing‐Hong
Published: June 2018

The cover picture shows a protocol of an anionic copolymerization of carbonyl sulfide (COS) with epoxides via alkali metal alkoxides. COS is an analogue of carbon dioxide (CO2), and can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. It causes acid rain, ozonosphere damage and haze by a series of photochemical reactions. Very simple and low‐cost alkali metal alkoxides are shown as effective catalysts, affording highly transparent poly(monothiocarbonate)s with 100% alternating degree, >99% tail‐to‐head (T‐H) content, high number‐average molecular weights with narrow molecular weight distributions. This is an environment‐friendly and atom‐economic process for making sulfur‐containing polymers. More details are discussed in the article by Zhang et al. on page 625–629.

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Automated classification of Wuyi rock tealeaves based on support vector machine
Authors: Lin Li‐Hui , Li Cheng‐Hsuan , Yang Sheng , Li Shao‐Zi , Wei Yi
Published: June 2018

This paper describes a new automated classification method for Wuyi rock tealeaves based on the best penalty parameter selection for the support vector machine with RBF (Radial Basis Function) kernel. A total of 3590 fresh tealeaf images of the representative Rou Gui and Shui Hsien varieties of Wuyi rock tea are collected in their natural habitat. Fourteen image features are extracted in terms of the leaf shape and texture. The automatic selection method is used to find the optimum RBF kernel parameter sigma, which is then applied to design an automatic parameter selection method to screen the best penalty parameter C for the classification of Wuyi rock tealeaves. In this study, the SVM classifier is used for the automated classification and recognition of the 14 image features. The contribution of the various features to the recognition rate of fresh tealeaves is evaluated to identify the key features for the classification and recognition of fresh Wuyi rock tealeaf images. The experimental results show that the proposed method improves the recognition rate of fresh tealeaves to 91.00%.
Synthesis and Characterization of Carboxyethylated Lignosulfonate
Authors: Bahrpaima Khatereh , Fatehi Pedram
Published: June 2018

Lignosulfonate is a byproduct of the sulfite pulping process and has limited use in industry. The main objective of this study was to investigate the carboxyethylation of lignosulfonate to increase its charge density to broaden its applications. The carboxyethylation of lignosulfonate was optimized under the conditions of 30 wt % NaOH, 2.0 mol mol−12‐chloropropinic acid/lignosulfonate, 90 °C, 0.5 h, and 0.03 mol 2‐chloropropinic acid, which produced carboxyethylated lignosulfonate with a charge density and molecular weight of −3.51 meq g−1and 46 493 g mol−1, respectively. The mechanism of the carboxyethylation reaction using 2‐chloropropinic acid by an SN1 pathway in an alkaline solution was discussed. Methylation was also used to mask the phenolic hydroxide groups of lignosulfonate to investigate if carboxyethylation occurred on aliphatic hydroxide groups of lignosulfonate. The produced carboxyethylated lignosulfonate was characterized by using FTIR spectroscopy, NMR spectroscopy, gel permeation chromatography, and elemental and functional group analyses. Basic1H‐1H 2 D COSY NMR spectroscopy was used to record the coupled spins of the carboxyethyl group on carboxyethylated lignosulfonate. The information from 1 D1H NMR and 2 D NMR COSY spectroscopy provided evidence for the existence of a 1‐carboxyethyl group on the carboxyethylated lignosulfonate structure.
A novel energy‐aware routing mechanism for SDN‐enabled WSAN
Authors: Al‐Hubaishi Mohammed , Çeken Celal , Al‐Shaikhli Ali
Published: June 2018

Energy consumption is one of the most important design constraints when building a wireless sensor and actuator network since each device in the network has a limited battery capacity, and prolonging the lifetime of the network depends on saving energy. Overcoming this challenge requires a smart and reconfigurable network energy management strategy. The Software‐Defined Networking (SDN) paradigm aims at building a flexible and dynamic network structure, especially in wireless sensor networks. In this study, we propose an SDN‐enabled wireless sensor and actuator network architecture that has a new routing discovery mechanism. To build a flexible and energy‐efficient network structure, a new routing decision approach that uses a fuzzy‐based Dijkstra's algorithm is developed in the study. The proposed architecture can change the existing path during data transmission, which is the key property of our model and is achieved through the adoption of the SDN approach. All the components and algorithms of the proposed system are modeled and simulated using the Riverbed Modeler software for more realistic performance evaluation. The results indicate that the proposed SDN‐enabled structure with fuzzy‐based Dijkstra's algorithm outperforms the one using the regular Dijkstra's and the ZigBee‐based counterpart, in terms of the energy consumption ratio, and the proposed architecture can provide an effective cluster routing while prolonging the network lifetime.
Towards providing optimal energy‐efficiency and throughput for IEEE 802.11 WLANs
Authors: Tuysuz Mehmet Fatih
Published: June 2018

IEEE 802.11 wireless network standard has become one of the most used wireless networking technologies for smart devices as it offers mobility support and low cost deployment. However, these devices deeply rely on the energy provided by their batteries, which results in limited running time. IEEE 802.11 network standard provides stations with carrier sense multiple access with collision avoidance for the medium access. Yet it results in stations to consume an important amount of power. Therefore, minimizing WiFi‐based energy consumption in smart devices has been received substantial attention in both academia and industry. Accordingly, this paper proposes a novel beacon‐based energy‐efficient collision‐free medium access control protocol for any type of IEEE 802.11 stations, regardless of being stationary or mobile, or having different amount of traffic flow, transmission rates, or traffic types. The proposed scheme is valid for all types of low or wide bandwidth, single or multiuser multiple‐input multiple‐output WLAN channels, such as IEEE 802.11a\b\g\n\ac. In the proposed scheme, energy saving is achieved, enabling stations to transmit on the right time and maintaining stations in the doze state during a predetermined sleep_time interval after each successful frame transmission, by making use of modified control and management frames of the standard IEEE 802.11 protocol. The proposed scheme reduces the probability of collisions and may allow stations to enter the collision‐free state, regardless of the number of stations on the channel and their traffic types. Widespread simulations have been executed to validate the efficiency of the proposed method. The results demonstrate that the proposed method significantly increases overall throughput and reduces power consumption of stations over IEEE 802.11 WLANs.
Diradical Character and Second Hyperpolarizability of Alkaline Earth Metal Inverse Sandwich Complexes Involving Cyclopentadienyl and Cyclooctatetraene Ligands
Authors: Takamuku Shota , Nakano Masayoshi
Published: June 2018

Invited for the cover of this issue are Shota Takamuku and Masayoshi Nakano from the group of Masayoshi Nakano, Graduate School of Engineering Science, Osaka University, Japan. The cover image shows a real inverse sandwich between two kinds of alkaline earth metal inverse sandwich model complexes.
Real Multicomponent Reactions: Synthesis of Highly Substituted 2‐Aminothiazoles
Authors: Richter Frank , Seifert Jennifer , Korb Marcus , Lang Heinrich , Banert Klaus
Published: June 2018

Allenyl isothiocyanates, which can be easily generated by flash vacuum pyrolysis, are known to readily form 1,3‐thiazoles with various nucleophiles. This is also true for heterocyclic aromatic amines and sterically hindered amines that are in other aspects used as non‐nucleophilic bases. The chemistry of these synthetically useful cumulenes is now expanded to the field of multicomponent reactions with the mentioned amines and selected electrophiles. In an efficient, catalyst‐free three‐component reaction (3‐CR) sequence, highly substituted heterocyclic compounds are formed containing the 2‐amino‐1,3‐thiazole skeleton. The reaction conditions and mechanisms leading to these potentially bioactive molecules were investigated and optimized for the synthesis of a small compound library.
Label‐free Electrochemical Bisphenol A Aptasensor Based on Designing and Fabrication of a Magnetic Gold Nanocomposite
Authors: Baghayeri Mehdi , Ansari Reza , Nodehi Marzieh , Razavipanah Iman , Veisi Hojat
Published: June 2018

The present study focuses on designing and fabricating an electrochemical aptasensor for the label free detection of bisphenol A (BPA) using gold nanoparticles (Au NPs) immobilized on functional cupper magnetic nanoparticles (CuFe2O4‐SH) and multiwall carbon nanotubes (MWCNTs) modified with aptamer and 6‐mercapto‐1‐hexanol (MCH). A number of analysis techniques were used to characterize the nanocomposite, including Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, elemental mapping analysis and energy dispersive x‐ray diffraction. The results of the analyses revealed that the fabricated aptasensor had an acceptable linearity index (0.05‐9 nM) with an ultralow detection limit (25.2 pM) when used to determine BPA. Electrochemical experiments were conducted using a [Fe(CN)6]3−/[Fe(CN)6]4− redox system. The results of the electrochemical tests indicated that the existence of Au NPs along with magnetic nanoparticles and MWCNTs in nanocomposite led to a synergistic augmentation on the surface of the modified electrode, thus facilitating the efficient sensing of BPA. This method is highly selective, sensitive and environmentally friendly. Moreover, proposed aptasensor has valuable potential applications in medical diagnostics and food industries where a fast and reliable detection of BPA is of paramount importance for the health of the public.
Validation of the Caregiver Skills (CASK) scale in Catalonia: Concordance between caregivers in attitudes and behaviours
Authors: Vintró‐Alcaraz Cristina , Mestre‐Bach Gemma , Steward Trevor , Lozano‐Madrid María , Agüera Zaida , Jiménez‐Murcia Susana , Pedraza Anna M. , Serrano‐Troncoso Eduardo , Ortiz García Ana E. , Rangil Teresa , Lorán Eulalia , Soriano‐Pacheco Jose , Medrano‐Puigdollers Laura , Bujalance‐Arguijo Sara , Badia Gina , Luque Maria , Tràfach Gloria , Gómez Osane , Peña Joan , Fabra Carme , Plana Maria Teresa , Raspall Reyes , Sánchez Isabel , Riesco Nadine , Granero Roser , Carretero‐Jardí Cristina , Treasure Janet , Fernández‐Aranda Fernando
Published: June 2018

Objective

The aim of this study was to validate a Spanish version of the Caregiver Skills scale (CASK) in a sample of eating disorder (ED) caregivers. A further aim was to examine the concordance/discrepancy between them (namely, between the mothers and fathers of ED patients).

Method

Two hundred sixty‐five ED caregivers were recruited from ED centers in Catalonia, Spain. Confirmatory factor analyses was used to test the factorial structure of the CASK scale. Cronbach's α was used to measure internal consistency of the CASK scales. A comparison of the CASK measures between respondents (mothers and fathers) was conducted using generalized estimating equations.

Results

Confirmatory factor analysis of the Spanish version of the CASK corroborated the strong factorial validity of the 6 factors of the original CASK questionnaire. Mothers and fathers did not differ significantly on CASK overall and subscale scores. There was however less concordance between parents on the bigger picture (ICC = 0.28) and biting your tongue (ICC = 0.08) subscales.

Conclusions

The CASK is a valid tool to assess ED‐related attitudes in Spanish‐speaking caregivers. Furthermore, caregivers and patients alike could stand to benefit from interventions focused on improving areas such as ED beliefs, effective communication, quality of life, and emotional distancing.
Eating disorders and non‐suicidal self‐injury: Structural equation modelling of a conceptual model
Authors: Vieira Ana Isabel , Machado Bárbara C. , Moreira Célia S. , Machado Paulo P.P. , Brandão Isabel , Roma‐Torres António , Gonçalves Sónia
Published: June 2018

Evidence suggests several risk factors for both eating disorders (ED) and nonsuicidal self‐injury (NSSI), but the relationships between these factors are not well understood. Considering our previous work and a conceptual model, this cross‐sectional study aimed to assess the relationships among distal and proximal factors for the presence of NSSI in ED. We assessed 245 ED patients with the Oxford Risk Factor Interview for ED. Structural equation modelling revealed that both distal and proximal factors were related to the presence of NSSI in ED, disclosing a mediating role of the proximal factors. Stressful life events mediated the relationship between childhood sexual abuse, peer aggression, and both ED and NSSI. Childhood physical abuse was related to ED and NSSI via substance use, negative self‐evaluation, and suicide attempts. Findings provided support for the conceptual model and highlight the possible mechanisms by which psychosocial factors may lead to ED and NSSI.
On the rapid discharge of subsea accumulators: remarks on the normed design method and proposal of improvement
Authors: Cipollone Roberto , Fatigati Fabio , Di Battista Davide , Allara Paolo , Carini Nicola
Published: June 2018

This study is focused on the design of the subsea accumulators currently used to deliver a pressurized fluid whose function is to actuate safety operations on a subsea well. API 16D, whose specifications regulate the design method of a bank of accumulators, was revised, discussed, and resumed in terms of a nomogram whose engineering value is useful for designers. An additional nomogram was derived allowing to perform the verification process which is suggested by the norm, in order to verify the fulfillment of the actuations requested to the accumulators. This verification phase caught the interest of the Authors: API 16D assumes for the design that the Functional Volume Requirement (FVR) – the sum of the quantities of pressurized fluid to be delivered for different sequenced‐in‐time functions – is delivered at the Minimum Operating Pressure (MOP) requested by the last actuation. This hypothesis simplifies the design, but the result cannot fulfill the previous functions because of the pressure lack (energy content in the pressurized propelling gas) which can happen. The use of the two nomograms proposed simplifies the application of the design procedure and allow to discuss main sensitivities of the variables involved (FVRs & MOPs), evidencing which variables deserve more attention and accuracy. In particular, the use of the second nomogram permits to verify that the right volumes of fluid during the actuations are delivered above a minimum pressure level, so guaranteeing the fulfillment of the function. It is based on a thermo‐fluid‐dynamic discharge modeling of the accumulators. The paper outlines a design direction which minimizes the number of accumulators and opens the way to a different design approach, based on a fully physical discharge process description.
A multi‐scale approach interpreting sediment processes and distribution from desert sand colour in central Saudi Arabia
Authors: Bradley Andrew V. , McLaren Sue J. , Al‐Dughairi Ahmed , Khalaf Nadia
Published: June 2018

In central Saudi Arabia the redness of sands observed on satellite imagery, often related to iron oxide amount, was used to better interpret geomorphic processes operating in the area. To compare variations between dune and interdune morphology, linear and dome dunes, and an ephemeral river partly buried under a sand sea, Nafud Al‐Thuwayrat, a multi‐scale approach was used to identify the spatial variation in causes of iron oxide amounts and colour. Macro‐scale mapping of Image Spectral Redness identified that the extent and intensity of colour grading across the orientation of well‐defined linear and dome dune types, interdunes and the Wadi Al‐Rimah, indicated sediment mixing of different provenance. Meso‐scale chemical, physical and colour analysis of surface samples indicated that iron oxide coated grains were present within all the samples and was not the sole control on Image Spectral Redness. The reddest sediments were the best sorted medium‐to fine‐quartz sands with iron oxide bearing chemistry and the paler sediments contained coarser sands with additional feldspars, calcite and gypsum. Micro‐scale analysis of grain characteristics found dune–interdune contrasts and that the reddest sands with iron coatings were of aeolian origin and the paler sands contained larger fluvial material mixed with reworked aeolian deposits. Dust in the area consists of high amounts of iron oxide and appears to be a major contributor to redness in the sand dunes. These controls on colour show the sand seas are paler westwards because a major river and local drainage systems deliver fluvial sediments from the carbonate and sandstone bedrock into the quartz‐rich aeolian material from the linear dunes. Evaporite deposits dominate in the paler interdunes, and south of the Wadi the dome dunes are the reddest as they are not migrating but building up. This multi‐scale approach has provided a modern analogy of processes for palaeoenvironmental studies. © 2018 John Wiley & Sons, Ltd.
A Simulation‐Based Method for Finding the Optimal Number of Options for Multiple‐Choice Items on a Test
Authors: Guo Hongwen , Zu Jiyun , Kyllonen Patrick
Published: June 2018

For a multiple‐choice test under development or redesign, it is important to choose the optimal number of options per item so that the test possesses the desired psychometric properties. On the basis of available data for a multiple‐choice assessment with 8 options, we evaluated the effects of changing the number of options on test properties (difficulty, reliability, and score comparability) using simulation. Using 2 criteria (low frequency and poor discrimination) to remove nonfunctioning options and 2 schemes (random and educated guessing) to model hypothetical response behavior for the removed options, we found that decreasing the number of options (from 8) created an easier test form but that a test form with reduced options could be more reliable if low‐discriminating options were removed and an educated guessing strategy were assumed. We present a rationale for the optimal number of options for this test being approximately 5, which would result in a shorter test while preserving its psychometric quality. Simulation methods discussed in this report could be applied to any test to compare the effects of changing the number of options.
Estimation of the optimal futures hedge ratio for equity index portfolios using a realized beta generalized autoregressive conditional heteroskedasticity model
Authors: Lai Yu‐Sheng
Published: June 2018

This paper employs a realized beta generalized autoregressive conditional heteroskedasticity model for optimal futures hedging. The model has a flexible structure and is complete because all observed returns and realized measures are jointly modeled in a system. This enables the incorporation of important features that may affect the hedge ratio estimation. The model is applied to equity indices, and substantial dependence between return and volatility indicates the essential of modeling statistical leverage. Predictive ability testing confirms the superiority of the model for reducing the hedged portfolio risk. The predictive ability of the model can translate into pronounced economic benefits, particularly for short‐term hedges.