bluuebunny/crossref_metadata_2025 huggingface dataset:
Charakterisierung von Wasserstoffbrücken zwischen Ionen in protischen ionischen Flüssigkeiten mittels NMR‐Deuteron‐Quadrupol‐Kopplungskonstanten – Unterschiede zu H‐Brücken in Amiden, Peptiden und Proteinen
Authors: Khudozhitkov Alexander E. , Stange Peter , Golub Benjamin , Paschek Dietmar , Stepanov Alexander G. , Kolokolov Daniil I. , Ludwig Ralf
Published: September 2017

Wir zeigen die ersten mittels Festkörper‐NMR gemessenen Deuteron‐Quadrupol‐Kopplungskonstanten (DQCCs) für eine Auswahl von protischen ionischen Flüssigkeiten (PILs). Die experimentellen Resultate werden gestützt durch Dichtefunktionalrechungen mit Dispersionskorrektur (DFT‐D3) und Moleküldynamik(MD)‐Simulationen. Die Werte der DQCCs der ND‐Bindung des Triethylammonium‐Kations sind die niedrigsten, welche bisher für Deuteronen in PILs gemessenen wurden, und lassen auf starke H‐Brücken zwischen Ionen schließen. Die NMR‐Kopplungsparameter werden mit denen in Amiden, Peptiden und Proteinen verglichen. Die DQCCs zeigen ein charakteristisches Verhalten bei Erhöhung der Wechselwirkungsstärke des Gegenions und der Variation der H‐Brücken‐Bindungsmotive. Wir zeigen die über große Temperaturbereiche gleichzeitig vorhandenen quadrupolaren Aufspaltungsmuster und die schmale Flüssigkeitsbande in den NMR‐Spektren, welche die heterogene Natur der PILs verdeutlichen.
Die Suche nach einkernigem Gold(II) und seine mögliche Rolle in Photokatalyse und Medizinalchemie
Authors: Heinze Katja
Published: September 2017

Die Chemie des Goldes wird von den allgegenwärtigen Oxidationsstufen +I und +III beherrscht. In einkernigen Goldverbindungen wird die Oxidationsstufe +II im Allgemeinen vermieden. In den letzten Jahren wurde Gold(II) wiederholt als Schlüsselintermediat in künstlichen Photosynthese‐Systemen mit Gold(III)‐Einheiten als Elektronenakzeptoren, in Gold‐katalysierten Photoredoxreaktionen und in der Radikalchemie vorgeschlagen. Dieser Kurzaufsatz fasst alle bestätigten und charakterisierten offenschaligen Gold(II)‐Komplexe zusammen. Aktuelle Erkenntnisse über Strukturmotive und Reaktivitätsmuster werden diskutiert. Spannende Entwicklungen auf den Gebieten der Photosynthese, der Photokatalyse und der Medizinalchemie werden umrissen.
Structure and Mechanism of the Monoterpene Cyclolavandulyl Diphosphate Synthase that Catalyzes Consecutive Condensation and Cyclization
Authors: Tomita Takeo , Kobayashi Masaya , Karita Yuma , Yasuno Yoko , Shinada Tetsuro , Nishiyama Makoto , Kuzuyama Tomohisa
Published: September 2017

We report the three‐dimensional structure of cyclolavandulyl diphosphate (CLPP) synthase (CLDS), which consecutively catalyzes the condensation of two molecules of dimethylallyl diphosphate (DMAPP) followed by cyclization to form a cyclic monoterpene, CLPP. The structures of apo‐CLDS and CLDS in complex with Tris, pyrophosphate, and Mg2+ ion were refined at 2.00 Å resolution and 1.73 Å resolution, respectively. CLDS adopts a typical fold for cis‐prenyl synthases and forms a homo‐dimeric structure. An in vitro reaction using a regiospecifically 2H‐substituted DMAPP substrate revealed the intramolecular proton transfer mechanism of the CLDS reaction. The CLDS structure and structure‐based mutagenesis provide mechanistic insights into this unprecedented terpene synthase. The combination of structural and mechanistic insights advances the knowledge of intricate terpene synthase‐catalyzed reactions.
Stoichiometric Reactions of CO2 and Indium‐Silylamides and Catalytic Synthesis of Ureas
Authors: Xu Maotong , Jupp Andrew R. , Stephan Douglas W.
Published: September 2017

The indium compounds In(N(SiMe3)2)2Cl⋅THF (2) and In(N(SiMe3)2)Cl2⋅(THF)n (3) were shown to react with CO2 to give [(Me3Si)2N)InX(μ‐OSiMe3)]2 (X=N(SiMe3)2 4, Cl 5). 0.05–2.0 mol % of the species 3 acts as a pre‐catalyst for the conversion of aryl and alkyl silylamines under CO2 (2–3 atm) to give the corresponding ureas in 70–99 % yields. A proposed mechanism is supported by experimental and computational data.
Asymmetric Iron‐Catalyzed C−H Alkylation Enabled by Remote Ligand meta‐Substitution
Authors: Loup Joachim , Zell Daniel , Oliveira João C. A. , Keil Helena , Stalke Dietmar , Ackermann Lutz
Published: September 2017

Highly enantioselective iron‐catalyzed C−H alkylations by inner‐sphere C−H activation were accomplished with ample scope. High levels of enantiocontrol proved viable through a novel ligand design that exploits a remote meta‐substitution on N‐heterocyclic carbenes within a facile ligand‐to‐ligand H‐transfer C−H cleavage.
Encapsulation of Isolated Luminophores within Supramolecular Cages
Authors: Handke Marcel , Adachi Takuji , Hu Chunhua , Ward Michael D.
Published: September 2017

The sequestration of luminophores within supramolecular polyhedral compartments of a crystalline zeolite‐like hydrogen‐bonded framework illustrates a unique approach to limiting the self‐quenching ordinarily exhibited at the high concentrations achievable in this framework. A range of differently sized luminescent guests, namely coumarin 1, coumarin 4, fluorescein, [Ru(bpy)3]Cl2, and rhodamine B, can be encapsulated in amounts of up to one molecule per cage, equivalent to a concentration of 0.175 m, which is significantly higher than the concentration at which aggregation‐induced quenching occurs in other media. The luminescence spectra of the encapsulated guests are consistent with the presence of isolated monomers and the absence of self‐quenching. The emission color of the single crystals can be tuned readily from blue to red through the choice of guest molecules. These observations promise an approach to organic solid‐state lasing compounds if crystals of sufficient size and quality can be prepared.
Iridium‐Catalyzed Direct C−H Amidation Polymerization: Step‐Growth Polymerization by C−N Bond Formation via C−H Activation to Give Fluorescent Polysulfonamides
Authors: Jang Yoon‐Jung , Hwang Soon‐Hyeok , Choi Tae‐Lim
Published: September 2017

We report a powerful strategy for activation of C−H bonds to produce polysulfonamides by an atom‐economical and green method using iridium‐catalyzed direct C−H amidation polymerization (DCAP). After screening various directing groups, additives, silver salts, concentrations, and temperatures to optimize DCAP, high‐molecular‐weight (up to 149 kDa) and defect‐free polysulfonamides were synthesized from various bis‐sulfonyl azides. Although these polymers do not have conventional fluorescent conjugated cores, they emit blue light with large Stokes shifts and high quantum yields upon photoexcitation owing to an excited‐state intramolecular proton‐transfer process.
Doubly N‐Confused [36]Octaphyrin(1.1.1.1.1.1.1.1): Isomerization, Bis‐Metal Coordination, and Topological Chirality
Authors: Mitsuno Koki , Yoshino Takafumi , Gupta Iti , Mori Shigeki , Karasawa Satoru , Ishida Masatoshi , Furuta Hiroyuki
Published: September 2017

A novel [36]octaphyrin analogue embedding two N‐confused pyrrole units demonstrated unique prototropy‐coupled isomerization between the Figure‐of‐eight and dumbbell conformers. Upon bis‐metal coordination, fixation of fully π‐conjugated Figure‐of‐eight structures was achieved as referred from the X‐ray crystal structure. Chirogenesis of the helical enantiomers was proved by intense circular dichroism (CD) response in the near infrared (NIR) region.
Mass Production and Pore Size Control of Holey Carbon Microcages
Authors: Zhang Lei , Liu Xiaoxiao , Dou Yuhai , Zhang Binwei , Yang Huiling , Dou Shixue , Liu Huakun , Huang Yunhui , Hu Xianluo
Published: September 2017

Architectural control of porous solids, such as porous carbon cages, has received considerable attention for versatile applications because of their ability to interact with liquids and gases not only at the surface, but throughout the bulk. Herein we report a scalable, facile spray‐pyrolysis route to synthesize holey carbon microcages with mosquito‐net‐like shells. Using the surfaces of water droplets as the growth templates, styrene–butadiene rubber macromolecules are controllably cross‐linked, and size‐controllable holes on the carbon shells are generated. The as‐formed carbon microcages encapsulating Si nanoparticles exhibit enhanced lithium‐storage performances for lithium‐ion batteries. The scalable, inexpensive synthesis of porous carbon microcages with controlled porosity and the demonstration of outstanding electrochemical properties are expected to extend their uses in energy storage, molecular sieves, catalysis, adsorbents, water/air filters, and biomedical engineering.
Fate of Worn‐Out Functional Teeth in the Upper Jaw Dentition of Sicyopterus japonicus (Gobioidei: Sicydiinae) During Tooth Replacement
Authors: Sahara Noriyuki , Moriyama Keita , Iida Midori , Watanabe Shun
Published: September 2017

Mochizuki and Fukui (Jpn J Ichthyol 30 () 27–36) studied the development and replacement of the upper jaw teeth in a Japanese fish species, Sicyopterus japonicus (Gobioidei: Sicydiinae), and they reported that worn‐out functional teeth in the upper jaw were not shed outside the skin but were taken into the soft tissue of the upper jaw and completely resorbed there. To date, however, this phenomenon appears poorly documented. Furthermore, the mechanism for the resorption of these teeth remains to be determined. In this study, we examined this phenomenon by using 3D microcomputed tomography (m‐CT), scanning electron microscopy (SEM), and various techniques of light (LM) and electron (EM) microcopy. This study demonstrated that the upper jaw dentition of this fish was more or less simultaneously replaced with the replacement occurring during short time periods and that the lingual movement of the replacement teeth to the functional tooth position advanced simultaneously in a given row. Furthermore, our study also revealed that many worn‐out functional teeth were engulfed by the oral epithelium, invaginated into the lingual shallow ditch of the premaxilla, and were resorbed/degraded completely by numerous foreign body giant cells rather than by odontoclasts during periods of at least three intervals of tooth replacement. The complete resorption/degradation of worn‐out functional teeth in the soft tissue of the upper jaw suggests the possibility of the reuse of their components (minerals such as Ca and P, including Fe) for rapid and successional production of new replacement teeth in the upper jaw of adult S. japonicus. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:111–124, 2018. © 2017 Wiley Periodicals, Inc.
First Natural Endocranial Cast of a Fossil Snake (Cretaceous of Patagonia, Argentina)
Authors: Triviño Laura N. , Albino Adriana M. , Dozo María T. , Williams Jorge D.
Published: September 2017

In this study, we describe a natural endocranial cast included in a partially preserved medium‐sized skull of the Upper Cretaceous South American snake Dinilysia patagonica. The endocast is composed of sedimentary filling of the cranial cavity in which the posterior brain, the vessels, the cranial nerves, and the inner ear surrounded by delicate semicircular canals, are represented. It is simple in form, with little differentiation between the three main areas (Forebrain, Midbrain, and Hindbrain), and without flexures. The nervous system is well preserved. The posterior brain surface is smooth, except for two small prominences that make up the cerebellum. A large inner ear is preserved on the right side; it consists of a voluminous central mass, the vestibule, which occupies most of the space defined by the three semicircular canals. In particular, the lateral semicircular canal is very close to the vestibule. This characteristic, in combination with the medium to large body size of Dinilysia, its large skull and dorsally exposed orbits, and vertebrae bearing a rather high neural spine on a depressed neural arch, suggests that this snake would have had a semifossorial lifestyle. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:9–20, 2018. © 2017 Wiley Periodicals, Inc.
Changes on the Pancreas in Experimental Diabetes and the Effect of Lycopene on These Changes: Pdx‐1, Ngn‐3, and Nestin Expressions
Authors: Sandikci Mustafa , Karagenc Levent , Yildiz Mustafa
Published: September 2017

The aim of the present study was to investigate changes occurring in the number of beta cells, as well as the expressions of Ngn‐3, nestin and Pdx‐1 of pancreatic progenitor cells in the pancreas of experimentally‐induced adult diabetic rats and to determine the effect of orally‐administered lycopene on these changes. Following the administration of 50 mg/kg streptozotocin to rats, four groups of animals were established: control + corn oil, control + lycopene, diabetic + corn oil and diabetic + lycopene. The animals in the control + lycopene and diabetic + lycopene groups received 4 mg/kg lycopene for a period of four weeks. The expressions of insulin, Ngn‐3, nestin, and Pdx‐1 were determined through immunohistochemistry in sections taken from pancreas tissue samples at the end of the experiment. The number of insulin‐positive cells was found to be significantly low in the diabetic groups compared to the control groups. In addition, the presence of Ngn‐3 and nestin‐positive cells within the exocrine pancreas surrounding the islands was noted in the diabetic groups. Lycopene, in general did not have any effect in any of the parameters analyzed in the present study. It is suggested that these cells would function as stem cells to replace the lost beta‐cell population. It is also suggested that it is possible to demonstrate the antioxidant effects of lycopene in the pancreas of diabetic rats by increasing the dose and duration of lycopene administration. Anat Rec, 300:2200–2207, 2017. © 2017 Wiley Periodicals, Inc.
The Hospital Anxiety and Depression scale: Factor structure and psychometric properties in older adolescents and young adults with autism spectrum disorder
Authors: Uljarević Mirko , Richdale Amanda L. , McConachie Helen , Hedley Darren , Cai Ru Ying , Merrick Hannah , Parr Jeremy R. , Le Couteur Ann
Published: September 2017

Despite the high frequency of anxiety and depression symptoms in individuals with Autism Spectrum Disorder (ASD) and a significant impact of these comorbidities on both individuals with ASD and their families, research on the validity of anxiety and depression measures in the ASD population is currently lacking. The aim of this study was to explore the psychometric properties of the Hospital Anxiety and Depression Scale [HADS; Zigmond & Snaith, ] in a sample of older adolescents and young adults with ASD. One hundred and fifty one participants (UK Transition longitudinal study: N = 106; 75 males, Mage = 16.04 years, SD = 1.28; Longitudinal Study of Australian Schools Leavers with ASD: N = 45, 30 males; Mage = 18.35 years, SD = 2.55) completed the HADS and a range of mental health and well‐being measures. Combination of the Principal Component Analysis and Parallel Analysis indicated two factors as an optimal solution in our sample, accounting for 43.77% of variance with factors being identical in terms of content with the structure found in the general population. Internal consistency was good for the HADS anxiety scale (HADS‐A; .82–.84) and acceptable for the HADS depression scale (HADS‐D; .60–.72). Convergent validity of both HADS‐A and HADS‐D scales was excellent and divergent validity was acceptable. Our study represents a significant contribution to the literature by providing an initial validation of the HADS in older adolescents and younger adults with ASD. Autism Res 2018, 11: 258–269. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

Research on the validity of measurement of anxiety and depression in ASD is currently lacking. The aim of this study was to explore the properties of the Hospital Anxiety and Depression Scale (HADS) in a sample of 151 young people with ASD. Participants completed HADS and a range of mental health and well‐being measures. Encouragingly, our findings suggest that HADS provides a reliable and valid assessment of anxiety and depression in ASD.
Highly efficient antibacterial diblock copolypeptides based on lysine and phenylalanine
Authors: Su Xiaokai , Zhou Xinyu , Tan Zhengzhong , Zhou Chuncai
Published: September 2017

A series of amphiphilic diblock copolypeptides (K30‐b‐F15, K30‐b‐F30, and K30‐b‐F45) were synthesized via N‐carboxy‐α‐amino‐anhydride ring‐opening polymerization. The copolypeptides had excellent antibacterial efficacy to both Gram positive (S. aureus) and Gram negative (E. coli) bacteria. The minimum inhibitory concentrations (MICs) against E. coli and S. aureus are 8 μg mL−1 and 2 μg mL−1, respectively, lower than most natural and artificial antimicrobial peptides (AMPs). The morphological changes of the bacteria treated with diblock copolypeptides were investigated by transmission electron microscopy; the results proved that the diblock copolypeptides had a similar antibacterial pore‐forming mechanism to natural cationic peptides. This was confirmed by laser scanning confocal microscope images. CCK‐8 results and the MICs showed that the diblock copolypeptides have high selectivity to bacteria, which suggested that the diblock copolypeptides could be excellent candidates to replace traditional antibiotics in future.
Formic acid as a secondary substrate for succinic acid production by metabolically engineered Mannheimia succiniciproducens
Authors: Ahn Jung Ho , Bang Junho , Kim Won Jun , Lee Sang Yup
Published: September 2017

There has been much effort exerted to reduce one carbon (C1) gas emission to address climate change. As one promising way to more conveniently utilize C1 gas, several technologies have been developed to convert C1 gas into useful chemicals such as formic acid (FA). In this study, systems metabolic engineering was utilized to engineer Mannheimia succiniciproducens to efficiently utilize FA. 13C isotope analysis of M. succiniciproducens showed that FA could be utilized through formate dehydrogenase (FDH) reaction and/or the reverse reaction of pyruvate formate lyase (PFL). However, the naturally favored forward reaction of PFL was found to lower the SA yield from FA. In addition, FA assimilation via FDH was found to be more efficient than the reverse reaction of PFL. Thus, the M. succiniciproducens LPK7 strain, which lacks in pfl, ldh, pta, and ack genes, was selected as a base strain. In silico metabolic analysis confirmed that utilization of FA would be beneficial for the enhanced production of SA and suggested FDH as an amplification target. To find a suitable FDH, four different FDHs from M. succiniciproducens, Methylobacterium extorquens, and Candida boidinii were amplified in LPK7 strain to enhance FA assimilation. High‐inoculum density cultivation using 13C labeled sodium formate was performed to evaluate FA assimilation efficiency. Fed‐batch fermentations of the LPK7 (pMS3‐fdh2 meq) strain was carried out using glucose, sucrose, or glycerol as a primary carbon source and FA as a secondary carbon source. As a result, this strain produced 76.11 g/L SA with the yield and productivity of 1.28 mol/mol and 4.08 g/L/h, respectively, using sucrose and FA as dual carbon sources. The strategy employed here will be similarly applicable in developing microorganisms to utilize FA and to produce valuable chemicals and materials from FA.
A role for the non‐receptor tyrosine kinase ACK1 in TNF‐alpha‐mediated apoptosis and proliferation in human intestinal epithelial caco‐2 cells
Authors: Zhao Xinmei , Lv Chaolan , Chen Shengbo , Zhi Fachao
Published: September 2017

The roles of tumor necrosis factor alpha (TNF‐alpha) and its mediators in cellular processes related to intestinal diseases remain elusive. In this study, we aimed to determine the biological role of activated Cdc42‐associated kinase 1 (ACK1) in TNF‐alpha‐mediated apoptosis and proliferation in Caco‐2 cells. ACK1 expression was knocked down using ACK1‐specific siRNAs, and ACK1 activity was disrupted using a small molecule ACK1 inhibitor. The Terminal deoxynucleotidyl transferase biotin‐dUTP Nick End Labeling (TUNEL) and the BrdU incorporation assays were used to measure apoptosis and cell proliferation, respectively. ACK1‐specific siRNA and the pharmacological ACK1 inhibitor significantly abrogated the TNF‐alpha‐mediated anti‐apoptotic effects and proliferation of Caco‐2 cells. Interestingly, TNF‐alpha activated ACK1 at tyrosine 284 (Tyr284), and the ErbB family of proteins was implicated in ACK1 activation in Caco‐2 cells. ACK1‐Tyr284 was required for protein kinase B (AKT) activation, and ACK1 signaling was mediated through recruiting and phosphorylating the down‐stream adaptor protein AKT, which likely promoted cell proliferation in response to TNF‐alpha. Moreover, ACK1 activated AKT and Src enhanced nuclear factor‐кB (NF‐кB) activity, suggesting a correlation between NF‐кB signaling and TNF‐alpha‐mediated apoptosis in Caco‐2 cells. Our results demonstrate that ACK1 plays an important role in modulating TNF‐alpha‐induced aberrant cell proliferation and apoptosis, mediated in part by ACK1 activation. ACK1 and its down‐stream effectors may hold promise as therapeutic targets in the prevention and treatment of gastrointestinal cancers, in particular, those induced by chronic intestinal inflammation.
Low‐Cost Noninvasive Real‐Time Imaging for Tubular Continuous‐Flow Crystallization
Authors: Jiang Mo , Braatz Richard D.
Published: September 2017

A key design limitation to the effective monitoring and control of continuous crystallization processes is the ability to characterize crystals in real time. A low‐cost system composed of a basic stereomicroscope and video camera for the in situ imaging of sub‐millimeter crystals through curved walls of millifluidic tubular crystallizers is described. Real‐time videos taken for millimeter‐size slurry slugs are used to guide the experimental design for a recently developed multiphase‐flow crystallization process, including the improvement of the slug aspect ratio, visualization of crystal shapes, and observation of the extent of aggregation. Design considerations are also discussed for the use of multiple stereomicroscopes in other continuous‐flow tubular experiments.
Surface Modification of Polysulfone Membranes Using Poly(Acrylic Acid)‐Decorated Alumina Nanoparticles
Authors: Ghaemi Negin , Daraei Parisa , Palani Shiva
Published: September 2017

Alumina nanoparticles were decorated with poly(acrylic acid) (PAA) as a hydrophilic polymer by thermal polymerization of acrylic acid in the presence of alumina nanoparticles. The obtained PAA‐decorated alumina (PAA‐d‐Al) nanoparticles were embedded in the polysulfone membrane matrix via nanofiller dispersion in the casting solution. The prepared membranes were characterized by porosity and water contact angle measurements, scanning electron and atomic force microscopy, and fouling tests using whey proteins. The presence of nanoparticles had significant effects on the membrane hydrophilicity and surface softness, resulting in fouling mitigation and flux recovery enhancement compared with the virgin polysulfone membrane. Moreover, the prepared membrane embedded with 0.25 wt % of PAA‐d‐Al nanofillers showed a remarkable durability and reusability during the filtration tests.
Photo‐Induced Assembly of a Luminescent Tetraruthenium Square
Authors: Laramée‐Milette Baptiste , Nastasi Francesco , Puntoriero Fausto , Campagna Sebastiano , Hanan Garry S.
Published: September 2017

Self‐assembly is a powerful synthetic tool that has led to the development of one‐, two‐ and three‐dimensional architectures. From MOFs to molecular flasks, self‐assembled materials have proven to be of great interest to the scientific community. Here we describe a strategy for the construction and de‐construction of a supramolecular structure through unprecedented photo‐induced assembly and dis‐assembly. The combination of two approaches, a [n×1]‐directional bonding strategy and a ligand photo‐dissociation strategy, allows the photo‐induced assembly of a polypyridyl RuII precursor into a discrete molecular square. Diffusion‐ordered NMR spectroscopy confirmed the synthesis of a higher volume species, while the identity of the species was established by high‐resolution mass spectrometry and single‐crystal X‐ray diffraction studies. The self‐assembled square is not obtained by classical thermal techniques in similar conditions, but is obtained only by light‐irradiation. The tetraruthenium square has an excited‐state lifetime (135 ns), 40 times that of its mononuclear precursor and its luminescence quantum yield (1.0 %) is three orders of magnitude higher. These remarkable luminescence properties are closely related to the relatively rigid square structure of the tetraruthenium assembly, as suggested by slow radiationless decay and transient absorption spectroscopy. The results described herein are a rare example of photo‐induced assembly and dis‐assembly processes, and can open the way to a new avenue in supramolecular chemistry, leading to the preparation of structurally organized supermolecules by photochemical techniques.
Molecular Switching in Confined Spaces: Effects of Encapsulating the DHA/VHF Photo‐Switch in Cucurbiturils
Authors: Petersen Michael Å. , Rasmussen Brian , Andersen Nicolaj N. , Sauer Stephan P. A. , Nielsen Mogens Brøndsted , Beeren Sophie R. , Pittelkow Michael
Published: September 2017

Confinement of reactive chemical species uniquely affects chemical reactivity by restricting the physical space available and by restricting access to interactions with the solvent. In Nature, for example, confined protein binding pockets govern processes following photoisomerization reactions and the isomerizations themselves. Here we describe the first example of a dihydroazulene/vinylheptafulvene (DHA/VHF) photo‐switch functioning in water, and we show how its switching behavior is strongly influenced by supramolecular interactions with a series of cucurbit[n]uril (CB) host molecules. In CB7 inclusion complexes, the kinetics of the thermal VHF‐to‐DHA back‐reaction is accelerated, while in CB8 inclusion complexes, the kinetics is slowed down as compared to the free photo‐switch. The effect of the CB encapsulation of the photo‐switch can be effectively canceled by introducing a guest that binds the CB more strongly. According to DFT calculations, a stabilization of the reactive s‐cis VHF conformer relative to the s‐trans VHF appears to be a contributing factor responsible for the accelerated back‐reaction when encapsulated in CB7.
Modulating the Structural Properties of α,γ‐Hybrid Peptides by α‐Amino Acid Residues: Uniform 12‐Helix Versus “Mixed” 12/10‐Helix
Authors: Misra Rajkumar , Raja K. Muruga Poopathi , Hofmann Hans‐Jörg , Gopi Hosahudya N.
Published: September 2017

The most important natural α‐ and 310‐helices are stabilized by unidirectional intramolecular hydrogen bonds along the helical cylinder. In contrast, we report here on 12/10‐helical conformations with alternately changing hydrogen‐bond directionality in sequences of α,γ‐hybrid peptides P1–P5 [P1: Boc‐Ala‐Aic‐Ala‐Aic‐COOH; P2: Boc‐Leu‐Aic‐Leu‐Aic‐OEt; P3: Boc‐Leu‐Aic‐Leu‐Aic‐Leu‐Aic‐Aib‐OMe; P4: Boc‐Ala‐Aic‐Ala‐Aic‐Ala‐Aic‐Ala‐OMe; P5: Boc‐Leu‐Aic‐Leu‐Aic‐Leu‐Aic‐Leu‐Aic‐Aib‐OMe; Aic=4‐aminoisocaproic acid, Aib=2‐aminoisobutyric acid] composed of natural α‐amino acids and the achiral γ4,4‐dimethyl substituted γ‐amino acid Aic in solution and in single crystals. The helical conformations are stabilized by alternating i→i+3 and i→i−1 intramolecular hydrogen bonds. The experimental data are supported by ab initio MO calculations. Surprisingly, replacing the natural α‐amino acids of the sequence by the achiral dialkyl amino acid Ac6c [P6: Boc‐Ac6c‐Aic‐Ac6c‐Aic‐Ac6c‐Aic‐Ac6c‐Aic‐Ac6c‐CONHMe; Ac6c = 1‐aminocyclohexane‐1‐carboxylic acid] led to a 12‐helix with unidirectional hydrogen bonds showing an entirely different backbone conformation. The results presented here emphasize the influence of the structure of the α‐amino acid residues in dictating the helix types in α,γ‐hybrid peptide foldamers and demonstrate the consequences for folding of small structural variations in the monomers.
Generation of Stable Ruthenium(IV) Ketimido Complexes by Oxidative Addition of Oxime Esters to Ruthenium(II): Reactivity Studies Based on Electronic Properties of the Ru−N Bond
Authors: Shimbayashi Takuya , Okamoto Kazuhiro , Ohe Kouichi
Published: September 2017

The reaction of an oxime ester with [Ru(PPh3)3X2] proceeded smoothly at room temperature to afford a stable RuIV ketimido complex as oxidative adduct. The structure of the complex was unambiguously determined by X‐ray crystallographic analysis, which showed an almost linear Ru−N−C array. The electronic properties of the nitrogen atom were estimated by DFT calculations, and the results suggested double‐bond character of the Ru−N bond. Kinetic studies and consideration of the substituent effect on the oxime ester led to the proposal of a reaction mechanism involving oxidative addition, which could proceed by N,O‐chelating coordination to the Ru center prior to N−O bond cleavage. The obtained Ru ketimido complex could be transformed into a ruthenacycle by C−H activation by a concerted metalation–deprotonation mechanism in dichloromethane/methanol. Ru ketimido complexes with a tethered alkyne or alkene moiety underwent chloroamination of unsaturated C−C bonds followed by C−H activation, which resulted in the formation of a ruthenacycle. Considering the LUMO of an isolated Ru ketimido complex, the chloroamination should proceed by a synchronous 1,3‐dipolar cycloaddition‐type mechanism. Insight into the character and reactivity of Ru ketimido complexes will be helpful for developments in the catalytic transformation of oxime esters.
Accessing Two‐Coordinate ZnII Organocations by NHC Coordination: Synthesis, Structure, and Use as π‐Lewis Acids in Alkene, Alkyne, and CO2 Hydrosilylation
Authors: Specklin David , Hild Frédéric , Fliedel Christophe , Gourlaouen Christophe , Veiros Luis F. , Dagorne Samuel
Published: September 2017

Discrete two‐coordinate ZnII organocations of the type (NHC)Zn−R+ are reported, thanks to NHC stabilization. In preliminary reactivity studies, such entities, which are direct cationic analogues of long‐known ZnR2 species, act as effective and tunable π‐Lewis acid catalysts in alkene, alkyne, and CO2 hydrosilylation.
A Combined Experimental and Theoretical Approach to Understand the Structure and Properties of N‐Methylpyrrolidone‐Based Protic Ionic Liquids
Authors: Panda Somenath , Kundu Kaushik , Umapathy Siva , Gardas Ramesh L.
Published: September 2017

Correlation of the structure and properties of ionic liquids (ILs) is essential for the development of optimized materials in the fields of gas capture and separation, battery electrolytes, and cellulose dissolution processes. In view of this, a detailed vibrational spectroscopic analysis and quantum‐chemical calculations were performed to explore the interionic interactions in ILs based on the N‐methylpyrrolidone cation and a carboxylate anion. FTIR and Raman spectroscopy were applied to identify the hydrogen‐bonding interactions between ion pairs, in which redshifted vibrational modes were observed as a function of the anion chain length. This observation was verified by the bond lengthening and enhanced hydrogen‐bonding energies, as manifested in the structure and natural bond orbital (NBO) calculations. Furthermore, conductivity was measured at different temperatures to envisage the effect of the alkyl chain on the mobility of ions in the ILs. Finally, rheological measurements were implemented to explain the flow behavior of these ILs, which revealed a decrease in shear viscosity with an increase in temperature, that is, a Newtonian trend over a range of shear rates. The observed trend in transport properties was supported by the ion‐pair binding energy. Stronger interactions between the IL cations and anions led to a decrease in the number of free ions and lowered the conductivity. In these protic ILs, the intermolecular N−H⋅⋅⋅O and C−H⋅⋅⋅O interactions played an important role in governing their physicochemical properties.
Nucleoside‐O‐Methyl‐(H)‐Phosphinates: Novel Monomers for the Synthesis of Methylphosphonate Oligonucleotides Using H‐Phosphonate Chemistry
Authors: Kostov Ondřej , Páv Ondřej , Rosenberg Ivan
Published: September 2017

This unit comprises the straightforward synthesis of protected 2′‐deoxyribonucleoside‐O‐methyl‐(H)‐phosphinates in both 3′‐ and 5′‐series. These compounds represent a new class of monomers compatible with the solid‐phase synthesis of oligonucleotides using H‐phosphonate chemistry and are suitable for the preparation of both 3′‐ and 5′‐O‐methylphosphonate oligonucleotides. The synthesis of 4‐toluenesulfonyloxymethyl‐(H)‐phosphinic acid as a new reagent for the preparation of O‐methyl‐(H)‐phosphinic acid derivatives is described. © 2017 by John Wiley & Sons, Inc.
Link abstraction models for multicarrier systems: A logistic regression approach
Authors: Carreras Mesa Alberto , Aguayo‐Torres Mari Carmen , Martin‐Vega Francisco J. , Gómez Gerardo , Blanquez‐Casado Francisco , Delgado‐Luque Isabel M. , Entrambasaguas Jose
Published: September 2017

Evaluation of complex wireless systems through simulations is commonly tackled with an abstraction of physical link behavior. This procedure is performed in 2 phases: Firstly, training is performed at the link level, resulting in a mapping function from signal‐to‐interference‐plus‐noise ratio (SINR) to block error rate (BLER); and secondly, physical layer signal processing is replaced by the resulting link‐level mapping function. Several methods have been proposed in the literature for link abstraction. The well‐known exponential effective SINR mapping (EESM) is likely to be the most extensively used procedure for multicarrier transmission. In short, EESM estimates an effective SINR from the whole set of SINRs of useful subcarriers by means of a single parameter mapping function, which must be previously optimized through training. Later on, BLER is assumed as that of the effective SINR over an additive white Gaussian noise channel. In this paper, we propose a novel method for BLER prediction named as logistic regression‐based link method (LRLM). Mean and standard deviation of the SINR set can accurately capture BLER behavior for wideband multicarrier systems through a simpler function, thus reducing the amount of information to be stored compared to EESM. Moreover, LRLM is very flexible and may include extra predictors to reduce the number of different models to be stored. Performance results show that LRLM is able to predict accurately the BLER for all modulation and coding schemes and transport block sizes defined for Long‐Term Evolution technology.
Fine needle aspiration biopsy diagnosis of primary clear cell chondrosarcoma: A case report
Authors: McHugh Kelsey E. , Emory Cynthia L. , Parks Graham E. , Kilpatrick Scott E.
Published: September 2017

Clear cell chondrosarcoma is a rare chondrosarcoma variant often involving the long bone epiphyses of young to middle aged adults. We report herein a case involving the left femoral head in a 25‐year‐old female with a 3‐month history of worsening left hip pain. Radiographs revealed a complex, multifocal and lytic lesion centered in the left proximal femoral epiphysis with involvement of the femoral neck. Computed tomography‐guided fine needle aspiration biopsy with concomitant core needle biopsy was performed, and a diagnosis of clear cell chondrosarcoma was rendered. Cytologic smears revealed aggregates of matrix material accompanied by a population of mostly uniform spindled to epithelioid and histiocytoid cells, rarely accompanied by osteoclast‐type giant cells. The patient underwent surgical resection with ‐total hip replacement, and subsequent pathologic examination confirmed the initial needle biopsy diagnosis. There has been no evidence of local recurrence or distant metastases with 3‐years follow‐up. To our knowledge, this is the first reported example of a primary clear cell chondrosarcoma initially evaluated by fine needle aspiration biopsy.
Invasive legumes can associate with many mutualists of native legumes, but usually do not
Authors: La Pierre Kimberly J. , Simms Ellen L. , Tariq Mohsin , Zafar Marriam , Porter Stephanie S.
Published: September 2017

Mutualistic interactions can strongly influence species invasions, as the inability to form successful mutualisms in an exotic range could hamper a host's invasion success. This barrier to invasion may be overcome if an invader either forms novel mutualistic associations or finds and associates with familiar mutualists in the exotic range. Here, we ask (1) does the community of rhizobial mutualists associated with invasive legumes in their exotic range overlap with that of local native legumes and (2) can any differences be explained by fundamental incompatibilities with particular rhizobial genotypes? To address these questions, we first characterized the rhizobial communities naturally associating with three invasive and six native legumes growing in the San Francisco Bay Area. We then conducted a greenhouse experiment to test whether the invasive legume could nodulate with any of a broad array of rhizobia found in their exotic range. There was little overlap between the Bradyrhizobium communities associated with wild‐grown invasive and native legumes, yet the invasive legumes could nodulate with a broad range of rhizobial strains under greenhouse conditions. These observations suggest that under field conditions in their exotic range, these invasive legumes are not currently associating with the mutualists of local native legumes, despite their potential to form such associations. However, the promiscuity with which these invading legumes can form mutualistic associations could be an important factor early in the invasion process if mutualist scarcity limits range expansion. Overall, the observation that invasive legumes have a community of rhizobia distinct from that of native legumes, despite their ability to associate with many rhizobial strains, challenges existing assumptions about how invading species obtain their mutualists. These results can therefore inform current and future efforts to prevent and remove invasive species.
Substrate‐Controlled Michael Additions of Titanium Enolates from Chiral α‐Benzyloxy Ketones to Conjugated Nitroalkenes
Authors: Gómez‐Palomino Alejandro , Barrio Adrián , García‐Lorente Pedro , Romea Pedro , Urpí Fèlix , Font‐Bardia Mercè
Published: September 2017

Lewis acid mediated substrate‐controlled reactions of the titanium(IV) enolates of chiral α‐benzyloxy ketones with conjugated nitroalkenes give 2,4‐anti‐4,5‐syn Michael adducts in good yields and diastereomeric ratios. The supplementary Lewis acid plays a key role in the outcome of these transformations, probably as a consequence of the formation of dimetallic enolates that increase the reactivity of the enolate and direct the approach of the nitroalkene. Importantly, the most appropriate Lewis acid depends on the electrophilic partner: TiCl4 is the most suitable Lewis acid for β‐aryl‐nitroalkenes, whereas the best results for β‐alkyl‐nitroalkenes are obtained with SnCl4. Finally, the nitro group of the resultant compounds can be converted into the corresponding amine, oxime, and nitrile groups under mild conditions, which permits the synthesis of a variety of enantiomerically pure derivatives in excellent yields.
Proglacial erosion rates and processes in a glacierized catchment in the Swiss Alps
Authors: Delaney Ian , Bauder Andreas , Huss Matthias , Weidmann Yvo
Published: September 2017

In the Swiss Alps, climatic changes have not only caused glacier retreat, but also likely increased sedimentation downstream of glaciers. This material either originates from below the glacier or from periglacial environments, which are exposed as glaciers retreat, and often consist of easily erodible sediment. Griesgletscher's catchment in the Swiss Alps was examined to quantify erosion in the proglacial area, possible hydrological drivers and contributions of the sub‐ and periglacial sources. Digital elevation models, created from annual aerial photographs, were subtracted to determine annual volume changes in the proglacial area from 1986 to 2014. These data show a strong increase in proglacial erosion in the decade prior to 2012, coincident with increasing proglacial area size. However, examination of the gradient between discharge and sediment evacuation, and modeled sediment transport, could suggest that the proglacial area began to stabilize and sediment supply is limited. The large influx of sediment into the proglacial reservoir, which is roughly 2.5 times greater than the amount of sediment eroded from the proglacial area, demonstrates the importance of subglacial erosion to the catchment's sediment budget. Although far more sediment originates subglacially, erosion rates in the proglacial area are over 50 times greater than the rest of the catchment. In turn, both sub‐ and periglacial processes, in addition to constraining sediment supply, must be considered for assessing future sediment dynamics as glacier area shrinks and proglacial areas grow. ©  2017 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.
On a planar thermal analysis of intumescent coatings
Authors: Ogrin Anita , Saje Miran , Hozjan Tomaž
Published: September 2017

The paper discusses a complex model for a nonstationary planar thermal analysis of expandable intumescent coatings. Following the existing one‐dimensional models, we develop novel and improved equations for the two‐dimensional thermal analysis of intumescent coatings. A progressive expansion due to chemical reactions, phase changes, and the time and temperature‐dependent thermal properties of the coating are considered. In the heating process, the coating may locally experience virgin, intumesced, or charred phases, and their transition with time. The rate of the density loss due to the pyrolysis reaction is described with the Arrhenius equation. The thickness of the coating is assumed to increase enormously during the pyrolysis. Consequently, the energy and mass equilibrium equations are formulated with respect to both the deformed and undeformed configuration. Since most of material properties of commercial products are not given by manufacturers, an innovative procedure is proposed to determine the time‐dependent thermal conductivities and remaining fundamental properties of the coating from the set of measured temperatures. This, together with the two‐dimensional formulation of the thermal equations with respect to the undeformed configuration, makes the present model unique and appropriate for the thermal analyses of an arbitrary steel cross section protected with intumescent coatings.
Economic significance of commodity return forecasts from the fractionally cointegrated VAR model
Authors: Dolatabadi Sepideh , Narayan Paresh Kumar , Nielsen Morten Ørregaard , Xu Ke
Published: September 2017

We model and forecast commodity spot and futures prices using fractionally cointegrated vector autoregressive (FCVAR) models generalizing the well‐known (non‐fractional) CVAR model to accommodate fractional integration. In our empirical analysis to daily data on 17 commodity markets, the fractional model is statistically superior in terms of in‐sample fit and out‐of‐sample forecasting. We analyze economic significance of the forecasts through dynamic (mean‐variance) trading strategies, leading to statistically significant and economically meaningful profits in most markets. We generally find that the fractional model generates higher profits on average, especially in the futures markets.
Loss of Gas6 and Axl signaling results in extensive axonal damage, motor deficits, prolonged neuroinflammation, and less remyelination following cuprizone exposure
Authors: Ray Alex K. , DuBois Juwen C. , Gruber Ross C. , Guzik Hillary M. , Gulinello Maria E. , Perumal Geoffrey , Raine Cedric , Kozakiewicz Lauren , Williamson Julie , Shafit‐Zagardo Bridget
Published: September 2017

The TAM (Tyro3, Axl, and MerTK) family of receptor tyrosine kinases (RTKs) and their ligands, Gas6 and ProS1, are important for innate immune responses and central nervous system (CNS) homeostasis. While only Gas6 directly activates Axl, ProS1 activation of Tyro3/MerTK can indirectly activate Axl through receptor heterodimerization. Therefore, we generated Gas6–/–Axl–/– double knockout (DKO) mice to specifically examine the contribution of this signaling axis while retaining ProS1 signaling through Tyro3 and MerTK. We found that naïve young adult DKO and WT mice have comparable myelination and equal numbers of axons and oligodendrocytes in the corpus callosum. Using the cuprizone model of demyelination/remyelination, transmission electron microscopy revealed extensive axonal swellings containing autophagolysosomes and multivesicular bodies, and fewer myelinated axons in brains of DKO mice at 3‐weeks recovery from a 6‐week cuprizone diet. Analysis of immunofluorescent staining demonstrated more SMI32+ and APP+ axons and less myelin in the DKO mice. There were no significant differences in the number of GFAP+ astrocytes or Iba1+ microglia/macrophages between the groups of mice. However, at 6‐weeks cuprizone and recovery, DKO mice had increased proinflammatory cytokine and altered suppressor of cytokine signaling (SOCS) mRNA expression supporting a role for Gas6‐Axl signaling in proinflammatory cytokine suppression. Significant motor deficits in DKO mice relative to WT mice on cuprizone were also observed. These data suggest that Gas6‐Axl signaling plays an important role in maintaining axonal integrity and regulating and reducing CNS inflammation that cannot be compensated for by ProS1/Tyro3/MerTK signaling.
Associations of alcohol intake, smoking, physical activity and obesity with survival following colorectal cancer diagnosis by stage, anatomic site and tumor molecular subtype
Authors: Jayasekara Harindra , English Dallas R. , Haydon Andrew , Hodge Allison M. , Lynch Brigid M. , Rosty Christophe , Williamson Elizabeth J. , Clendenning Mark , Southey Melissa C. , Jenkins Mark A. , Room Robin , Hopper John L. , Milne Roger L. , Buchanan Daniel D. , Giles Graham G. , MacInnis Robert J.
Published: September 2017

The influence of lifestyle factors on survival following a diagnosis of colorectal cancer (CRC) is not well established. We examined associations between lifestyle factors measured before diagnosis and CRC survival. The Melbourne Collaborative Cohort Study collected data on alcohol intake, cigarette smoking and physical activity, and body measurements at baseline (1990–1994) and wave 2 (2003–2007). We included participants diagnosed to 31 August 2015 with incident stages I–III CRC within 10‐years post exposure assessment. Information on tumor characteristics and vital status was obtained. Tumor DNA was tested for microsatellite instability (MSI) and somatic mutations in oncogenes BRAF (V600E) and KRAS. We estimated hazard ratios (HRs) for associations between lifestyle factors and overall and CRC‐specific mortality using Cox regression. Of 724 eligible CRC cases, 339 died (170 from CRC) during follow‐up (average 9.0 years). Exercise (non‐occupational/leisure‐time) was associated with higher CRC‐specific survival for stage II (HR = 0.25, 95% CI: 0.10–0.60) but not stages I/III disease (p for interaction = 0.01), and possibly for colon and KRAS wild‐type tumors. Waist circumference was inversely associated with CRC‐specific survival (HR = 1.25 per 10 cm increment, 95% CI: 1.08–1.44), independent of stage, anatomic site and tumor molecular status. Cigarette smoking was associated with lower overall survival, with suggestive evidence of worse survival for BRAF mutated CRC, but not with CRC‐specific survival. Alcohol intake was not associated with survival. Survival did not differ by MSI status. We have identified pre‐diagnostic predictors of survival following CRC that may have clinical and public health relevance.