bluuebunny/crossref_metadata_2025 huggingface dataset:
COMPOSITIONS OF HYDROCARBONS AND HETEROORGANIC COMPOUNDS IN ORGANIC SUBSTANCE AND PRODUCTS OF THERMAL DECOMPOSITION UNDER SUPERCRITICAL CONDITIONS OF KEROGEN IN OIL SHALE FROM CHIM-LOPTYUG DEPOSIT
Authors: Kovalenko Elena Yu. , Sagachenko Tatyana A. , Min Raisa S. , Patrakov Yury F.
Published: July 2018

New data are presented on the chemical nature of the organic substance in the sample of oil shale from the Upper Jurassic deposits, the section of the Chim-Loptyug area of the Yarengsky shale-bearing territory in the Timan-Severouralsk region (the Komi Republic) and in the products of its thermal dissolution in the supercritical flow of the aromatic solvent (benzene). The soluble organic substance in the sample under study was shown to be highly resinous and sour. Thermolysis of shale material in benzene under supercritical conditions increased the yield of the liquid product due to the destruction of bridge (C-S) and C-C bonds in kerogen. The contents of sulfur and oil components were found to increase in the composition of the resulting pyrolyzate. According to the chromatographic-mass spectrometric analysis bitumoid and pyrolyzate oils contained normal and isoprenoid alkanes, polycycloalkanes, mono- and polycyclic aromatic hydrocarbons and heteroorganic compounds. The pyrolyzate oils are characterized by the presence of unsaturated compounds in the hydrocarbon composition and a wider set of sulfur- and oxygen-containing structures. The sets of hydrocarbon and hetero-organic compounds identified in the pyrolyzate oils are typical for oily components in oils, which enables to consider pyrolizate as a raw material for the production of a wide range of fuels and lubricants, as well as valuable products for national economy. Based on the data on the distribution of biomarker hydrocarbons and the values of the calculated geochemical coefficients of the accumulation of organic substance in the investigated sample of oil shale it was established to occur in a sharply reducing situation in argillaceous deposit with a high contribution of marine phytoplankton to the initial biomass. The low thermal maturity of the organic substance indicates its high generation potential.Forcitation:Kovalenko E.Yu., Sagachenko T.A., Min R.S., Patrakov Yu.F. Compositions of hydrocarbons and heteroorganic compounds in organic substance and products of thermal decomposition under supercritical conditions of kerogen in oil shale from Chim-Loptyug deposit. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 98-104
SYNTHESIS AND COORDINATION PROPERTIES OF COBALT COMPLEXES OF 5-PHENYL-2,3,7,8,12,18-HEXAMETHYL-13,17-DIETHYLPORPHYRIN AND ITS NITRO-SUBSTITUTED IN ORGANIC SOLVENTS
Authors: Kuvshinova Elizaveta M. , Bykova Maria A. , Vershinina Irina A. , Gornukhina Olga V. , Lyubimova Tatyana V. , Semeikin Alexander S.
Published: July 2018

5-Phenyl-2,3,7,8,12,18-hexamethyl-13,17-diethylporphyrin (1), 5-phenyl-10,20-dinitro-2,3,7,8,12,18-hexamethyl -13,17-diethylporphyrin (2), 5- (p-nitrophenyl) -2,3,7,8,12,18-hexamethyl-13,17-diethylporphyrin (3) weresynthesized. The kinetics of formation and dissociation of their cobalt complexes in pyridine and acetic acid was studied. It was found that the change in reactivity upon transition from porphyrin 1 to 2 during complexation in acetic acid is due to an increase in the degree of deformation of the tetrapyrrole aromatic nucleus and the electronic effect of nitro groups. This is manifested by a strong bathochromic shift of all absorption bands in electronic spectra. It is shown that the opposite effect of the deformation effect and the i-effect of nitro groups on the rate of the reaction of formation of metal porphyrin leads to an insignificant change in the kinetic parameters. In pyridine, which has weakly basic properties, the reaction rate increases sharply with the introduction of nitro groups at position of 10, 20 of the porphyrin core. This is due to the fact that the deviation of the tetrapyrrole macrocycle from planarity leads to an increase in the reaction rate. It was found that a spherical distortion of the planar structure of porphyrins (1-3) in the series 1<3<2 relatively slightly influence on the rate of dissociation of their cobalt complexes. Apparently, this is due to the fact that coordination of the cobalt cation leads to a more flat structure of the tetrapyrrole macrocycle and the electronic effects of the nitro groups is the main contribution to the rate of the dissociation reaction of porphyrins (1-3).Forcitation:Kuvshinova E.M., Bykova M.A., Vershinina I.A., Gornukhina O.V., Lyubimova T.V., Semeikin A.S. Synthesis and coordination properties of cobalt complexes of 5-phenyl-2,3,7,8,12,18-hexamethyl-13,17-diethylporphyrin and its nitro-substituted in organic solvents. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 43-48
The extent of adaptive wild introgression in crops
Authors: Janzen Garrett M. , Wang Li , Hufford Matthew B.
Published: July 2018

The study of crop evolution has focused primarily on the process of initial domestication. Post-domestication adaptation during the expansion of crops from their centers of origin has received considerably less attention. Recent research has revealed that, in at least some instances, crops have received introgression from their wild relatives that has facilitated adaptation to novel conditions encountered during expansion. Such adaptive introgression could bear importantly on the basic study of domestication, affecting estimates of several evolutionary processes of interest (e.g., the strength of the domestication bottleneck, the timing of domestication, the targets of selection during domestication). Identification of haplotypes introgressed from the wild may also aid the identification of alleles that are beneficial under particular environmental conditions. Here we review mounting evidence for substantial adaptive wild introgression in several crops and consider the implications of such gene flow to our understanding of crop histories.
Progress in the discovery of amphipod crustaceans
Authors: Arfianti Tri , Wilson Simon , Costello Mark John
Published: July 2018

At present, amphipod crustaceans comprise 9,980 species, 1,664 genera, 444 subfamilies, and 221 families. Of these, 1,940 species (almost 20%) have been discovered within the last decade, including 18 fossil records for amphipods, which mostly occurred in Miocene amber and are probably all freshwater species. There have been more authors describing species since the 1950s and fewer species described per author since the 1860s, implying greater taxonomic effort and that it might be harder to find new amphipod species, respectively. There was no evidence of any change in papers per author or publication life-times of taxonomists over time that might have biased apparent effort. Using a nonhomogeneous renewal process model, we predicted that by the year 2100, 5,600 to 6,600 new amphipod species will be discovered. This indicates that about two-thirds of amphipods remain to be discovered which is twice the proportion than for species overall. Amphipods thus rank amongst the least well described taxa. To increase the prospect of discovering new amphipod species, studying undersampled areas and benthic microhabitats are recommended.
Digging the compromise: investigating the link between limb bone histology and fossoriality in the aardvark (Orycteropus afer)
Authors: Legendre Lucas J. , Botha-Brink Jennifer
Published: July 2018

Bone microstructure has long been known as a powerful tool to investigate lifestyle-related biomechanical constraints, and many studies have focused on identifying such constraints in the limb bones of aquatic or arboreal mammals in recent years. The limb bone microstructure of fossorial mammals, however, has not been extensively described. Furthermore, so far, studies on this subject have always focused on the bone histology of small burrowers, such as subterranean rodents or true moles. Physiological constraints associated with digging, however, are known to be strongly influenced by body size, and larger burrowers are likely to exhibit a histological profile more conspicuously influenced by fossorial activity. Here, we describe for the first time the limb bone histology of the aardvark (Orycteropus afer), the largest extant burrowing mammal. The general pattern is very similar for all six sampled limb bones (i.e., humerus, radius, ulna, femur, tibia, and fibula). Most of the cortex at midshaft is comprised of compacted coarse cancellous bone (CCCB), an endosteal tissue formed in the metaphyses through the compaction of bony trabeculae. Conversely, the periosteal bone is highly resorbed in all sections, and is reduced to a thin outer layer, suggesting a pattern of strong cortical drift. This pattern contrasts with that of most large mammals, in which cortical bone is of mostly periosteal origin, and CCCB, being a very compliant bone tissue type, is usually resorbed or remodeled during ontogeny. The link between histology and muscle attachment sites, as well as the influence of the semi-arid environment and ant-eating habits of the aardvark on its bone microstructure, are discussed. We hypothesize that the unusual histological profile of the aardvark is likely the outcome of physiological constraints due to both extensive digging behavior and strong metabolic restrictions. Adaptations to fossoriality are thus the result of a physiological compromise between limited food availability, an environment with high temperature variability, and the need for biomechanical resistance during digging. These results highlight the difficulties of deciphering all factors potentially involved in bone formation in fossorial mammals. Even though the formation and maintaining of CCCB through ontogeny in the aardvark cannot be unambiguously linked with its fossorial habits, a high amount of CCCB has been observed in the limb bones of other large burrowing mammals. The inclusion of such large burrowers in future histological studies is thus likely to improve our understanding of the functional link between bone growth and fossorial lifestyle in an evolutionary context.
Effect of Lithiation on the Microstructure of a Cobalt Foam Processed by Freeze Casting
Authors: Gubicza Jenő , Németh Regina , Park Hyeji , Kim Kyungbae , Kim Jae‐Hun , Óvári Mihály , Mohai Miklós , Choe Heeman
Published: July 2018

Surface‐oxidized Co is a promising candidate as a negative electrode material in lithium ion batteries (LIBs). The stability of electrode materials in LIBs during charging/discharging is crucial from the viewpoint of their applications. In this study, experiments are carried out to investigate the influence of lithiation on the microstructure of Co foam processed by freeze casting. The main phase in the strut interiors of the as‐prepared foam was hcp‐Co with a grain size of ≈0.38 µm and a considerable lattice strain. Thirty cycles of charging/discharging caused no changes in the phase composition, the grain size, and microstrain in the struts. However, the crystalline surface oxide layer is practically amorphized and a strong oxygen/cobalt ratio gradient developed during lithiation; additionally, the foam is enriched with Li. These changes led to a fragmentation of the surface into scutes.
Piezo‐Phototronic Effect for Enhanced Flexible MoS2/WSe2 van der Waals Photodiodes
Authors: Lin Pei , Zhu Laipan , Li Ding , Xu Liang , Pan Caofeng , Wang Zhonglin
Published: July 2018

The recent discoveries of transition‐metal dichalcogenides (TMDs) as novel 2D electronic materials hold great promise to a rich variety of artificial van der Waals (vdWs) heterojunctions and superlattices. Moreover, most of the monolayer TMDs become intrinsically piezoelectric due to the lack of structural centrosymmetry, which offers them a new degree of freedom to interact with external mechanical stimuli. Here, fabrication of flexible vdWs p–n diode by vertically stacking monolayer n‐MoS2 and a few‐layer p‐WSe2 is achieved. Electrical measurement of the junction reveals excellent current rectification behavior with an ideality factor of 1.68 and photovoltaic response is realized. Performance modulation of the photodiode via piezo‐phototronic effect is also demonstrated. The optimized photoresponsivity increases by 86% when introducing a −0.62% compressive strain along MoS2 armchair direction, which originates from realigned energy‐band profile at MoS2/WSe2 interface under strain‐induced piezoelectric polarization charges. This new coupling mode among piezoelectricity, semiconducting, and optical properties in 2D materials provides a new route to strain‐tunable vdWs heterojunctions and may enable the development of novel ultrathin optoelectronics.
Composition‐Tuned Wide Bandgap Perovskites: From Grain Engineering to Stability and Performance Improvement
Authors: Zhou Yang , Jia Yong‐Heng , Fang Hong‐Hua , Loi Maria Antonietta , Xie Fang‐Yan , Gong Li , Qin Min‐Chao , Lu Xin‐Hui , Wong Ching‐Ping , Zhao Ni
Published: July 2018

Wide bandgap (WB) organic–inorganic hybrid perovskites (OIHPs) with a bandgap ranging between 1.7 and 2.0 eV have shown great potential to improve the efficiency of single‐junction silicon or thin‐film solar cells by forming a tandem structure with one of these cells or with a narrow bandgap perovskite cell. However, WB‐OIHPs suffer from a large open‐circuit voltage (Voc) deficit in photovoltaic devices, which is associated with the phase segregation of the materials under light illumination. In this work the photoinstability is demonstrated and Voc loss can be addressed by combining grain crystallization and grain boundary passivation, achieved simultaneously through tuning of perovskite precursor composition. Using FA0.17Cs0.83PbI3–xBrx (x = 0.8, 1.2 1.5, and 1.8), with a varied bandgap from 1.72 to 1.93 eV, as the model system it is illustrated how precursor additive Pb(SCN)2 should be matched with a proper ratio of FAX (I and Br) to realize large grains with defect‐healed grain boundaries. The optimized WB‐OIHPs show good photostability at both room‐temperature and elevated temperature. Moreover, the corresponding solar cells exhibit excellent photovoltaic performances with the champion Voc/stabilized power output efficiency reaching 1.244 V/18.60%, 1.284 V/16.51%, 1.296 V/15.01%, and 1.312 V/14.35% for WB‐OIHPs with x = 0.8, 1.2, 1.5, and 1.8, respectively.
The Application of Hollow Structured Anodes for Sodium‐Ion Batteries: From Simple to Complex Systems
Authors: Xie Fangxi , Zhang Lei , Ye Chao , Jaroniec Mietek , Qiao Shi‐Zhang
Published: July 2018

Hollow structures exhibit fascinating and important properties for energy‐related applications, such as lithium‐ion batteries, supercapacitors, and electrocatalysts. Sodium‐ion batteries, as analogs of lithium‐ion batteries, are considered as promising devices for large‐scale electrical energy storage. Inspired by applications of hollow structures as anodes for lithium‐ion batteries, the application of these structures in sodium‐ion batteries has attracted great attention in recent years. However, due to the difference in lithium and sodium‐ion batteries, there are several issues that need to be addressed toward rational design of hollow structured sodium anodes. Herein, this research news article presents the recent developments in the synthesis of hollow structured anodes for sodium‐ion batteries. The main strategies for rational design of materials for sodium‐ion batteries are presented to provide an overview and perspectives for the future developments of this research area.
Designing Efficient Energy Funneling Kinetics in Ruddlesden–Popper Perovskites for High‐Performance Light‐Emitting Diodes
Authors: Yantara Natalia , Bruno Annalisa , Iqbal Azhar , Jamaludin Nur Fadilah , Soci Cesare , Mhaisalkar Subodh , Mathews Nripan
Published: July 2018

Mixed Ruddlesden–Popper (RP) perovskites are of great interest in light‐emitting diodes (LEDs), due to the efficient energy transfer (funneling) from high‐bandgap (donor) domains to low‐bandgap (acceptor) domains, which leads to enhanced photoluminescence (PL) intensity, long PL lifetime, and high‐efficiency LEDs. However, the influence of reduced effective emitter centers in the active emissive film, as well as the implications of electrical injection into the larger bandgap donor material, have not been addressed in the context of an active device. The electrical and optical signatures of the energy cascading mechanisms are critically assessed and modulated in a model RP perovskite series ((C8H17NH3)2(CH(NH2)2)m−1PbmBr3m+1). Optimized devices demonstrate a current efficiency of 22.9 cd A−1 and 5% external quantum efficiency, more than five times higher than systems where funneling is absent. The signature of nonideal funneling in RP perovskites is revealed by the appearance of donor electroluminescence from the device, followed by a reduction in the LED performance
Interface Engineering for All‐Inorganic CsPbI2Br Perovskite Solar Cells with Efficiency over 14%
Authors: Yan Lei , Xue Qifan , Liu Meiyue , Zhu Zonglong , Tian Jingjing , Li Zhenchao , Chen Zhen , Chen Ziming , Yan He , Yip Hin‐Lap , Cao Yong
Published: July 2018

In this work, a SnO2/ZnO bilayered electron transporting layer (ETL) aimed to achieve low energy loss and large open‐circuit voltage (Voc) for high‐efficiency all‐inorganic CsPbI2Br perovskite solar cells (PVSCs) is introduced. The high‐quality CsPbI2Br film with regular crystal grains and full coverage can be realized on the SnO2/ZnO surface. The higher‐lying conduction band minimum of ZnO facilitates desirable cascade energy level alignment between the perovskite and SnO2/ZnO bilayered ETL with superior electron extraction capability, resulting in a suppressed interfacial trap‐assisted recombination with lower charge recombination rate and greater charge extraction efficiency. The as‐optimized all‐inorganic PVSC delivers a high Voc of 1.23 V and power conversion efficiency (PCE) of 14.6%, which is one of the best efficiencies reported for the Cs‐based all‐inorganic PVSCs to date. More importantly, decent thermal stability with only 20% PCE loss is demonstrated for the SnO2/ZnO‐based CsPbI2Br PVSCs after being heated at 85 °C for 300 h. These findings provide important interface design insights that will be crucial to further improve the efficiency of all‐inorganic PVSCs in the future.
Dotted Core–Shell Nanoparticles for T1‐Weighted MRI of Tumors
Authors: Shen Zheyu , Song Jibin , Zhou Zijian , Yung Bryant C. , Aronova Maria A. , Li Yan , Dai Yunlu , Fan Wenpei , Liu Yijing , Li Zihou , Ruan Huimin , Leapman Richard D. , Lin Lisen , Niu Gang , Chen Xiaoyuan , Wu Aiguo
Published: July 2018

Gd‐based T
1‐weighted contrast agents have dominated the magnetic resonance imaging (MRI) contrast agent market for decades. Nevertheless, they are reported to be nephrotoxic and the U.S. Food and Drug Administration has issued a general warning concerning their use. In order to reduce the risk of nephrotoxicity, the MRI performance of the Gd‐based T
1‐weighted contrast agents needs to be improved to allow a much lower dosage. In this study, novel dotted core–shell nanoparticles (FeGd‐HN3‐RGD2) with superhigh r
1 value (70.0 mM−1 s−1) and very low r
2/r
1 ratio (1.98) are developed for high‐contrast T
1‐weighted MRI of tumors. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and histological analyses show good biocompatibility of FeGd‐HN3‐RGD2. Laser scanning confocal microscopy images and flow cytometry demonstrate active targeting to integrin αvβ3 positive tumors. MRI of tumors shows high tumor ΔSNR for FeGd‐HN3‐RGD2 (477 ± 44%), which is about 6‐7‐fold higher than that of Magnevist (75 ± 11%). MRI and inductively coupled plasma results further confirm that the accumulation of FeGd‐HN3‐RGD2 in tumors is higher than liver and spleen due to the RGD2 targeting and small hydrodynamic particle size (8.5 nm), and FeGd‐HN3‐RGD2 is readily cleared from the body by renal excretion.
Nasal airflow resistance measured by rhinomanometry in a healthy population of China
Authors: Ren Lei , Zhang Luo , Duan Su , Zhang Wei , Zhang Yuan
Published: July 2018

Background

Although nasal congestion is among the most common symptoms in subjects suffering from nasal diseases, relatively few data on normal airflow resistance are available for reference, especially in healthy Chinese subjects. The aim of present study was therefore to objectively measure the normal airflow resistance by rhinomanometry, and calculate mean and standard reference intervals in a cohort of healthy Chinese subjects.

Methods

A total of 1084 participants were recruited in Huairou region in Beijing, China from November to December 2011. All participants were required to complete 2 questionnaires and undergo nasal examination and objective assessment of nasal resistance by rhinomanometry and acoustic rhinometry.

Results

A total of 704 adults completed both questionnaires and nasal examinations; with 505 (71.73%) subjects considered “healthy” based on negative medical history, absence of nasal symptoms, and normal findings by nasal examination. The mean total nasal resistance in the congested nose was 0.168 Pa/cm3/sec (95% CI, 0.068 to 0.268 Pa/cm3/sec) at 75 Pa pressure and 0.243 Pa/cm3/sec (95% CI, 0.112 to 0.374 Pa/cm3/sec) at 150 Pa pressure. The mean total nasal resistance in males was significantly lower compared to females at 75 Pa and 150 Pa (p < 0.001). The mean unilateral nasal resistance was 0.357 Pa/cm3/sec (95% CI, 0.034 to 0.680 Pa/cm3/sec) at 75 Pa and 0.511 Pa/cm3/sec (95% CI, 0.086 to 0.936 Pa/cm3/sec) at 150 Pa, with no significant difference between males and females. Application of a vasoconstrictor decreased both total and unilateral nasal resistance, which was significant at 75 Pa.

Conclusion

These reference values maybe useful for the Chinese clinicians in evaluating the nasal function and in choosing and assessing efficacy of therapy for nasal congestion in Chinese patients.
A Far‐Red Fluorescent DNA Binder for Interaction Studies of Live Multidrug‐Resistant Pathogens and Host Cells
Authors: Schulte Leon N. , Heinrich Benedikt , Janga Harshavardhan , Schmeck Bernd T. , Vázquez Olalla
Published: July 2018

Transgene expression of green fluorescent protein (GFP) has facilitated the spatiotemporal investigation of host–pathogen interactions; however, introduction of the GFP gene remains challenging in drug‐resistant bacteria. Herein, we report a novel far‐red fluorescent nucleic acid stain, 6‐TramTO‐3, which efficiently labels bacteria through a DNA binding mode without affecting growth and viability. Exemplarily, we stained Klebsiella pneumoniae, a major threat to hospitalized patients, and deciphered divergent interaction strategies of antibiotic‐resistant and antibiotic‐sensitive Klebsiella strains with immune cells. 6‐TramTO‐3 constitutes an off‐the‐shelf reagent for real‐time analysis of bacterial infection, including strains for which the use of genetically encoded reporters is not feasible. Eventually, our approach may aid the development of strategies to combat a major worldwide health threat: multidrug‐resistant bacteria.
Control of the Stereochemical Course of [4+2] Cycloaddition during trans‐Decalin Formation by Fsa2‐Family Enzymes
Authors: Kato Naoki , Nogawa Toshihiko , Takita Ryo , Kinugasa Kiyomi , Kanai Misae , Uchiyama Masanobu , Osada Hiroyuki , Takahashi Shunji
Published: July 2018

Enzyme‐catalyzed [4+2] cycloaddition has been proposed to be a key transformation process in various natural product biosynthetic pathways. Recently Fsa2 was found to be involved in stereospecific trans‐decalin formation during the biosynthesis of equisetin, a potent HIV‐1 integrase inhibitor. To understand the mechanisms by which fsa2 determines the stereochemistry of reaction products, we sought an fsa2 homologue that is involved in trans‐decalin formation in the biosynthetic pathway of an enantiomerically opposite analogue, and we found phm7, which is involved in the biosynthesis of phomasetin. A decalin skeleton with an unnatural configuration was successfully constructed by gene replacement of phm7 with fsa2, thus demonstrating enzymatic control of all stereochemistry in the [4+2] cycloaddition. Our findings highlight enzyme‐catalyzed [4+2] cycloaddition as a stereochemically divergent step in natural product biosynthetic pathways and open new avenues for generating derivatives with different stereochemistry.
Bis(η5:η1‐pentafulvene)niobium(V) Complexes: Efficient Synthons for Niobium Carbene and Imido Derivatives
Authors: Manßen Manfred , Dierks Anna , de Graaff Simon , Schmidtmann Marc , Beckhaus Rüdiger
Published: July 2018

Transition‐metal carbene complexes and their reactivities are a key topic of chemistry. They are an integral part of researches in catalysis, organic synthesis, coordination chemistry, and numerous other areas. In this context, we report the synthesis of a low‐valent bis(η5:η1‐(di‐p‐tolyl)‐pentafulvene)niobium chloride. Owing to the π‐η5:σ‐η1 coordination mode of the pentafulvenes and the resulting high nucleophilic character of the exocyclic carbon atom of the ligand, the bis(η5:η1‐pentafulvene)niobium complex is able to achieve the umpolung of a coordinated vinyl unit and the resulting formation of the first η5:η1 cyclic niobium Schrock carbene complex. This new synthetic route is, in comparison to classical α‐hydrogen elimination reactions or thermolysis of diazo compounds, completely unprecedented. The reactivity of the cyclic carbene function and the remaining fulvene ligand is demonstrated by double N−H bond activation of primary amines to niobium imido complexes.
Bor(II)‐Kationen: Ein Zusammenspiel zwischen Lewis‐Paar‐Akzeptor‐ und Elektronendonor‐Eigenschaften
Authors: Widera Anna , Vogler Daniel , Wadepohl Hubert , Kaifer Elisabeth , Himmel Hans‐Jörg
Published: July 2018

Bor(III)‐Kationen finden in der Synthesechemie eine breite Anwendung als Lewis‐Säuren. Im Gegensatz dazu sind Bor(II)‐Kationen ausgesprochen selten, und ihre Chemie ist nahezu unerforscht. Sie sind zugleich Lewis‐Säuren und Elektronendonoren, Eigenschaften, die gewöhnlich mit katalytisch aktiven Metallkomplexen der späten Übergangsmetallreihe assoziiert werden. Dieses zweifache Reaktivitätsmuster lässt eine reiche und vielfältige Chemie erwarten. Hier berichten wir über eine einfache Synthese einiger neuer Bor(II)‐Kationen beginnend mit einem besonderen Diboran mit zwei leicht austauschbaren Triflatsubstituenten. Durch die Erhöhung der π‐Akzeptorstärke neutraler σ‐Donoren als Reaktionspartner konnte zum ersten Mal die kombinierte Lewis‐Acidität und Elektronendonor‐Eigenschaft der Bor(II)‐Kationen zur Reduktion organischer Moleküle angewendet werden. Die Ergebnisse unserer Untersuchung bahnen den Weg zur Anwendung dieser ungewöhnlichen Verbindungen in der Synthesechemie.
Selection of Secondary Structures of Heterotypic Supramolecular Peptide Assemblies by an Enzymatic Reaction
Authors: Li Jie , Zhan Ziqing , Du Xuewen , Wang Jiaqing , Hong Brandon , Xu Bing
Published: July 2018

In a model study to investigate the consequence of reactions of intrinsically disordered regions (IDRs) of proteins in the context of the formation of highly ordered structures, we found that enzymatic reactions control the secondary structures of peptides during assembly. Specifically, phosphorylation of an α‐helix‐dominant peptide results in mostly disordered conformations, which become β‐strand‐dominant after enzymatic dephosphorylation to regenerate the peptide. In the presence of another peptide largely with a β‐strand conformation, direct coassembly of the peptides results in amorphous aggregates consisting of α‐helix and β‐strand peptides, but the enzymatically generated peptide coassemblies (from the phosphopeptide) mainly adopt a β‐strand conformation and form ordered structures (e.g., nanofibers). These results indicate that enzymatic dephosphorylation instructs conformationally flexible peptides to adopt thermodynamically favorable conformations in homotypic or heterotypic supramolecular assemblies.
A three‐dimensional (3D) manganese (II) coordination polymer: Synthesis, structure and catalytic activities
Authors: Pal Souvik , Maiti Sudip , Nayek Hari Pada
Published: July 2018

A new Mn (II)‐containing coordination polymer, [Mn6(Ipa)6(ad)⋅6H2O] (1; Ipa = isophthalate ligand; ad = adenine), was synthesized by reacting hydrated manganese nitrate with isophthalic acid and adenine under solvothermal reaction conditions. Polymer 1 was characterized using single‐crystal X‐ray diffraction analysis and other techniques such as Fourier transform infrared spectroscopy, elemental analyses and powder X‐ray diffraction. The solid‐state structure of 1 confirmed the formation of a three‐dimensional framework structure based on Mn6 secondary building units. Phase purity of bulk 1 and its thermal stability were investigated. Polymer 1 was evaluated for its performance as a heterogeneous catalyst for the Henry (nitroaldol) reaction of nitromethane with several aldehydes. The recyclability of 1 and heterogeneity of the reaction were also explored. A plausible mechanism for such reaction is proposed. To the best of our knowledge, polymer 1 represents the first example of a Mn (II)‐ and adenine‐containing coordination polymer as well as the first example of a Mn (II)‐containing coordination polymer that has been employed for the Henry reaction.
Phosphomolybdic acid as a bifunctional catalyst for Friedel–Crafts type dehydrative coupling reaction
Authors: Yang Guo‐Ping , Dilixiati Dilireba , Yang Tao , Liu Dong , Yu Bing , Hu Chang‐Wen
Published: July 2018

Phosphomolybdic acid (H3PMo12O40) was found to be a bifunctional catalyst for C─C bond formation via the dehydrative reaction of diarylmethanols with various nucleophiles, including 2‐naphthols, indoles, benzofuran and benzothiophene. The protons in the catalyst might play a critical role in the activation of alcohol, while the polyanion was advantageous for stabilizing the carbocation species. The cooperative catalytic system showed its own merits, such as high reaction rate, low catalyst loading, mild conditions, excellent yields (up to 99%) and good functional group compatibility.
Iron oxide modified with pyridyl‐triazole ligand for stabilization of gold nanoparticles: An efficient heterogeneous catalyst for A3 coupling reaction in water
Authors: Gholinejad Mohammad , Zareh Fatemeh , Najera Carmen
Published: July 2018

Fe3O4 nanoparticles were modified with pyridyl‐triazole ligand and the new magnetic solid was applied for the stabilization of very small and uniform gold nanoparticles. The resulting magnetic material, Fe3O4@PT@Au, was characterized using various methods. These gold nanoparticles on a magnetic support were applied as an efficient heterogeneous catalyst for the three‐component reaction of amines, aldehydes and alkynes (A3 coupling) in neat water with 0.01 mol% Au loading. Using magnetic separation, this catalyst could be recycled for seven consecutive runs with very small decrease in activity. Characterization of the reused catalyst did not show appreciable structural modification.
DFT/TDDFT insight into the impact of ring size of the NHC chelating unit of high effective phosphorescent Platinum (II) complexes
Authors: Yan Xi , Li Wenqian , Zhang Huize , Cai Wanlin , Wang Jian , Shen Wei
Published: July 2018

Uncovering the photodeactivation mechanisms of unique N‐heterocyclic carbene (NHC)‐based transition metal complexes is favorable for designing more high‐efficiency phosphorescent materials. In this work, four bidentate platinum (II) complexes with NHC‐chelate are investigated by the density functional theory (DFT) and time‐dependent density functional theory (TDDFT) to probe into how the ring size of NHC‐chelate unit influences on electronic structures and the phosphorescent properties. To illustrate the photodeactivation mechanisms clearly, three significant photodeactivation processes (radiative decay process, temperature‐independent and temperature‐dependent nonradiative decay processes) were taken into consideration. We stated that radiative decay rate constants kr slightly increased with declined number of NHC‐chelate ring, owing to the gradually larger SOC matrix elements between the T1 state and Sn states. Combining the temperature‐independent with temperature‐dependent nonradiative decay processes, the nonradiative decay rate knr is Pt‐4 (five‐membered) < Pt‐3 (six‐membered) < Pt‐2 (seven‐membered) < Pt‐1 (eight‐membered). The calculated results testify that the decrease of size of the NHC chelating unit is a reliable insurance to improve the quantum yield. The designed complex Pt‐4 with five‐membered NHC‐ring can serve as a highly efficient phosphorescent material in the future. The results indicated controlling the ring size of NHC‐chelate is a feasible method to tune phosphorescence properties of Pt (II) complexes.
Chemoselective hydrogenation of nitriles to primary amines catalyzed by water‐soluble transition metal catalysts
Authors: Nait Ajjou Abdelaziz , Robichaud André
Published: July 2018

The water‐soluble rhodium complex generated in situ from [Rh (COD)Cl]2 in aqueous ammonia has been revealed as a highly efficient catalyst for the hydrogenation of aromatic nitriles, to primary amines with excellent yields. The catalyst is also highly selective towards primary amines in the case of sterically hindered aliphatic nitriles. The catalytic system can also be recycled and re‐used with no significant loss of activity.
Sulfonated octa‐substituted Co(II) phthalocyanines immobilized on silica matrix as catalyst for Thiuram E synthesis
Authors: Vashurin Artur , Marfin Yury , Tarasyuk Ilya , Kuzmin Ilya , Znoyko Serafima , Goncharenko Aleksandr , Rumyantsev Evgeny
Published: July 2018

Silica nanoparticles were obtained during the work according to two different sol–gel methods. In first one Schtrober's technique and series of cobalt phthalocyanine metal complexes varying in peripheral substituents were used. Second method was performed using the same complexes but differed in applying surface‐active substance (SAS) and two precursors – tetraethoxysilane (TEOS) and aminopropyltrimethoxysilane (APTMOS). All obtained hybrid materials were analyzed via SEM, the size of single particle was studied, which in all cases was about 200 nm. In order to investigate hybrid's characteristics laser diffraction and liquid nitrogen adsorption methods were applied. Distinction in pore's specific volume of differently‐obtained nanoparticles was found. Catalytic activity of all obtained materials were tested in conversion of N,N‐diethylcarbamodithiolate to thiuram E. Effect of peripherally substituted phthalocyanines and morphology of matrixes were manifested on catalytic activity of the hybrids.
Corporate environmental responsibility and competitiveness: The maquiladora industry of the Mexican northern borderlands
Authors: Ayala‐Ponce Nancy , Vilchis‐Vidal Agustín , Picard‐Ami Maria Luisa
Published: July 2018

This article sustains that competitive advantages can be developed when industries implement corporate environmental responsibility (CER) programs systematically and strategically, as demonstrated by data provided by a case study conducted with maquiladora industries in Ciudad Juárez, on the Mexico–United States border. In that study, organizational theory and studies were combined with qualitative analytical techniques to explore relationships between environmental management programs and competitive advantage indicators such as innovation, corporate image, and cost reduction. The data were collected from semistructured interviews with managers of environmental issues and from the official documents of seven regional maquiladoras. The findings showed a direct relationship between implementation of CER programs and activities with the resulting evolution of competitive advantages. Further analysis shows that it is the systematic and strategic implementation of CER programs as part of an overall managerial strategy that allows for the generation of competitive advantages through the mediation of innovation as a key factor.
Analysing the failure factors of eco‐friendly home appliances based on a user‐centered approach
Authors: Shin Jungwoo , Kang Suna , Lee Donghyun , Hong Bum Il
Published: July 2018

Pro‐environmental consumption is necessary for sustainable development, but the sales of eco‐friendly products have been limited. In this regard, the present study analyses the failure factors of eco‐friendly product consumption activation from the consumer's perspective, specifically focusing on detergent‐free washing machines, which are representative innovative products of eco‐friendly home appliances. This study analyses: (1) the attitude‐behaviour gap that occurs in the consumer decision‐making process, and (2) the consumer preference with respect to the core attributes. A recursive model considering the decision‐making stage was constructed and a mixed logit model was utilized to analyse the preference for the core attributes. As a result, the product compatibility and transfer of expert information must be secured to reduce the attitude‐behaviour gap. Additionally, washing power is an important attribute for improving product saleability. The analysis framework of this study can be used to establish sustainable policies for activating eco‐friendly products.
The influence of carbon cost pass through on the link between carbon emission and corporate financial performance in the context of the European Union Emission Trading Scheme
Authors: Brouwers Roel , Schoubben Frederiek , Van Hulle Cynthia
Published: July 2018

In this study we examine, within the context of the European Union Emission Trading Scheme, whether firms' ability to pass through carbon costs affects the link between carbon emission and corporate financial performance. Our results, controlling for the endogenous relationship between carbon emission and financial performance, and robust to a number of alternative financial performance measures, demonstrate that good carbon emission performance does not always pay off. In fact, we find that lower levels of carbon emission are only rewarded if firms are not able to pass on carbon costs to consumers, either due to industry characteristics or firm‐specific carbon efficiency. Our results are in line with the view that as pollution is associated with increasing environmental costs, this negative impact of pollution on financial performance is mitigated for “carbon cost pass through” firms.
Personal informatics systems for supporting self‐regulation in online learning environments
Authors: García‐Solórzano David , Santamaría Eugènia , Morán José A. , Cobo Germán , Monzo Carlos
Published: July 2018

Personal informatics (PI) systems have emerged as powerful tools for helping people to be aware of their behaviors in diverse domains. Nevertheless, little attention has been devoted to educational scenarios. For this reason, this paper presents an educational PI system called Glance and, moreover, evaluates its usefulness in two fully online undergraduate courses.
MicroRNA‐378 regulates epithelial–mesenchymal transition and metastasis of melanoma by inhibiting FOXN3 expression through the Wnt/β‐catenin pathway
Authors: Sun Mengyao , Ma Xiaona , Tu Chen , Wang Xiaopeng , Qu Jianqiang , Wang Shuang , Xiao Shengxiang
Published: July 2018

MicroRNAs (miRNAs) participate in the development and progression of melanoma. However, while dysregulation of microRNA‐378 (miR‐378) has been seen in various cancer types, its clinical importance and function in melanoma are poorly elucidated. In this work, miR‐378 expression in melanoma and in adjacent non‐cancerous tissue was evaluated with a quantitative real‐time polymerase chain reaction. A series of assays (wound healing, Transwell, and nude mouse subcutaneous tumor model) were used to investigate the implications of abnormal miR‐378 regulation on melanoma cell migration and invasion in vitro, and on tumorigenicity in vivo. Prediction and conformation of the miR‐378 target gene was undertaken using bioinformatic analysis and luciferase reporter system. Expression of miR‐378 was often increased in melanoma, and shown to potentiate its migration, invasion, and tumorigenicity. miR‐378 acted, at least partially, through inhibition of the potential target FOXN3 and via Wnt/β‐catenin pathway activation. The findings indicate that miR‐378 triggers melanoma development and progression. This miRNA could be a novel diagnostic and prognostic biological marker and provide utility for targeted treatment of melanoma.
A Density Functional Theory Study of the Mechanism of Direct Glucose Dehydration to 5‐Hydroxymethylfurfural on Anatase Titania
Authors: Li Guanna , Pidko Evgeny A. , Hensen Emiel J. M. , Nakajima Kiyotaka
Published: July 2018

A new mechanism for glucose dehydration to HMF without the intermediate isomerization to fructose is discussed for surface models of anatase TiO2 using periodic density functional theory calculations. Activation of the glucose at glucose's C3‐OH position by titania starts the reaction resulting in adsorbed 3‐deoxyglucosone. The mechanistic study reveals two possible pathways for the acyclic form of glucose. Comparison of different surface models shows that the presence of tetrahedral Ti4+ species on a defective TiO2(101) anatase surface is essential for explaining the activity. Synergy between a strong Lewis acidic Ti site and a vicinal basic oxygen site of a TiOH group is essential to establish the direct conversion of glucose to HMF. IR spectroscopy of adsorbed chloroform in the presence of water confirms the presence of water tolerant Lewis acid sites in close proximity to basic sites. In conventional glucose dehydration, Lewis acid sites and proton donors act as catalytic sites for efficient sequential isomerization‐dehydration to HMF, while direct dehydration to HMF requires the cooperation of Lewis acid‐base pairs.
Ultrafast Electrodeposition of Ni Metal and NiFe Hydroxide Composites with Heterogeneous Nanostructures as High Performance Multifunctional Electrocatalysts
Authors: Zhuang Shuxian , Wang Linan , Hu Hanjun , Tang Yang , Chen Yongmei , Sun Yanzhi , Mo Hengliang , Yang Xiaojin , Wan Pingyu , Khan Zia Ul Haq
Published: July 2018

Water electrolysis provides an efficient method to produce hydrogen as clean energy source. Developing high activity electro‐catalysts towards the oxygen evolution reaction (OER) is crucial to improve the energy‐conversion efficiency of water electrolysis. In this work, heterogeneous nanostructures of NiFe hydroxide composites decorated by Ni metal were directly grown on a porous nickel foam (NF) substrate through an ultrafast electrodeposition process at a large cathodic current density of 1.5 A cm−2 within only 2 seconds. The as‐prepared Ni/NiFe (OH)x–1500 electrode offers a low OER overpotential of 240 mV at 10 mA cm−2 and 290 mV at 100 mA cm−2, a small Tafel slope of 36 mV Dec−1, which are superior to those of a commercial RuO2/Ti electrode. Moreover, Ni/NiFe (OH)x–1500 shows good stability and low cell voltage in the long‐time alkaline‐water splitting. Additionally, the Ni/NiFe (OH)x–1500 electrode also displays excellent electro‐catalytic activity toward the oxidation of hydrazine and glucose. This work provides a facile and rapid method to obtain high performance multifunctional electro‐catalysts.
Simultaneous Multiplex Potentiostatic Electroanalysis with Liquid‐Junction‐Removed Reference Electrode System using a Closed Bipolar Electrode
Authors: Inoue Kumi Y. , Ikegawa Miho , Ito‐Sasaki Takahiro , Takano Shinichiro , Shiku Hitoshi , Matsue Tomokazu
Published: July 2018

The front cover artwork is provided by Prof. K. Y. Inoue, Prof. T. Matsue, and Mr. T. Iwama from Tohoku University, Sendai (Japan). The image shows an electrochemical measuring device with six sample cells and one reference cell. Simultaneous multiplex amperometry and voltammetry are available with integrated reference system without a liquid junction. Read the full text of the Communication at 10.1002/celc.201800536.
Pancake Bonding: An Unusual Pi‐Stacking Interaction
Authors: Kertesz Miklos
Published: July 2018

A category of parallel π‐stacking interaction, termed pancake bonding, is surveyed. The main characteristics are: the interaction occurs among radicals with highly delocalized π‐electrons in their singly occupied molecular orbitals (SOMOs), the contact distances in the π‐stacking direction are shorter than the typical van der Waals distances, and the stabilization obtained by the bonding combination of the SOMO orbitals leads to direct atom‐to‐atom overlap with strong orientational preferences. These atypical intermolecular interactions contain a component of electron sharing between the radicals that can be viewed as covalent‐like. Pancake bonded dimers characteristically have low‐lying singlet and triplet states and show characteristic interlayer vibrational modes. Pancake bonded aggregates serve as molecular components in many conducting and other functional organic materials. The role of van der Waals (vdW) interactions in pancake bonded dimers, chains, and other aggregates is different from closed shell vdW aggregates: here the Pauli repulsions reduce the attractive dispersion interaction significantly. Fluxionality between π‐ and σ‐bonded aggregates often occur in the context of pancake bonding. Both experimental and computational aspects are reviewed.
The Deep Sea Osmolyte TrimethylamineN‐Oxide and Macromolecular Crowders Rescue the Antiparallel Conformation of the Human Telomeric G‐Quadruplex from Urea and Pressure Stress
Authors: Knop Jim‐Marcel , Patra Satyajit , Harish Balasubramanian , Royer Catherine A. , Winter Roland
Published: July 2018

Organisms are thriving in the deep sea at pressures up to the 1 kbar level, which imposes severe stress on the conformational dynamics and stability of their biomolecules. The impact of osmolytes and macromolecular crowders, mimicking intracellular conditions, on the effect of pressure on the conformational dynamics of a human telomeric G‐quadruplex (G4) DNA is explored in this study employing single‐molecule Förster resonance energy transfer (FRET) experiments. In neat buffer, pressurization favors the parallel/hybrid state of the G4‐DNA over the antiparallel conformation at ≈400 bar, finally leading to unfolding beyond 1000 bar. High‐pressure NMR data support these findings. The folded topological conformers have different solvent accessible surface areas and cavity volumes, leading to different volumetric properties and hence pressure stabilities. The deep‐sea osmolyte trimethylamineN‐oxide (TMAO) and macromolecular crowding agents are able to effectively rescue the G4‐DNA from unfolding in the whole pressure range encountered on Earth.
Chiral Bambusurils for Enantioselective Recognition of Carboxylate Anion Guests
Authors: Sokolov Jan , Šindelář Vladimír
Published: July 2018

Synthesis of the first enantiomerically pure chiral bambusurils is reported. The bambusurils were prepared on the gram scale without using any chromatography techniques. The bambusurils formed supramolecular complexes with all tested chiral carboxylates including amino acids and drug molecules with the enantioselectivity ranging from 1.1 to 3.2.