bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Insights into the Ring‐Opening Polymerization of β‐Butyrolactone Catalyzed by Chromium(III) Salphen Complexes
Authors: Vagin Sergei , Winnacker Malte , Kronast Alexander , Altenbuchner Peter T. , Deglmann Peter , Sinkel Carsten , Loos Robert , Rieger Bernhard 
Published: September 2015

AbstractThe heterogeneous nature of β‐butyrolactone (BL) polymerization towards tactic poly(3‐hydroxybutyrate) (PHB) in the presence of chromium(III) salphen (salphen=N,N′‐disalicylidene‐o‐phenylenediamine) complexes is supported by a number of experimental observations. Depending on the substitution pattern, initially soluble chromium(III) salphen chloride complexes can generate microcrystalline agglomerates under the polymerization conditions, driven by formation of μ‐OH bridges between metal centers. Coordinated water molecules are suggested to be the source of such bridging ligands. The formation of these/this heterogeneous species is a prerequisite for the stereocontrolled ring‐opening polymerization (ROP) of BL, whereas both iso‐ and syndioselective enchainment occurs simultaneously. According to the analysis of the 13C NMR spectra of the polymers, the ratio of the corresponding triads depends on a number of parameters in a not yet understood manner. Besides dual stereoselectivity, the heterogeneous chromium(III) salphen species feature catalytic sites with different activities, which is reflected in the very broad molecular mass distribution of the produced PHB. Highly active catalytic sites cause the formation of polymer chains with a high molecular mass at the beginning of polymerization. The described behavior is not inherent to truly homogeneous chromium salphen complexes and is more in line with a bimetallic ROP mechanism proposed earlier, which requires a particular mutual spatial orientation of two salphen complexes for the efficient catalysis of BL polymerization.
Solvent‐Mediated Transformation from Achiral to Chiral Nickel(II) Metal–Organic Frameworks and Reassembly in Solution
Authors: Li Xiaoju , Yu Zhenjiang , Li Xinxiong , Guo Xiaofang 
Published: September 2015

AbstractReactions of 5‐nitroisophthalic acid (NO2‐H2ip), 1,4‐bis(imidazol‐1′‐yl)butane (bimb), and Ni(NO3)2⋅6 H2O gave rise to four metal–organic frameworks (MOFs), [Ni2(NO2‐ip)2(bimb)1.5]n (1), [Ni4(NO2‐ip)3(bimb)2(OH)2(H2O)]n ⋅(CH3CH2OH)0.5 n (2), [Ni(NO2‐ip)(bimb)1.5(H2O)]n⋅(H2O)n ⋅(CH3CH2OH)0.5 n (3), and [Ni(NO2‐ip) (bimb)(μ‐H2O)]n⋅(H2O)n (4). The metal/ligand ratio, pH value, and solvent exerted a subtle but crucial influence on the formation of complexes 1–4, which possess different visual color and crystal structures. Complex 1 exhibits a twofold interpenetrating 3D pillared bilayer framework composed of binuclear and mononuclear NiII units, whereas complex 2 is a 3D chiral network that consists of asymmetric tetranuclear NiII units. Complexes 3 and 4 are 3D layer‐pillared frameworks that consist of mononuclear NiII ions and a 3D six‐connected network of μ‐water‐bridged dinuclear NiII units, respectively. Interestingly, achiral 4 can be transformed into chiral 2 by using a solvent‐mediated single‐crystal‐to‐single‐crystal process without any chiral auxiliary. Magnetic analyses of 2 and 4 show the occurrence of antiferromagnetic interactions. Complex 3 is difficult to obtain directly as a single solid phase, but it can be homogeneously formed by solvent‐mediated transformations from 1, 2, and 4.
Sensitization of NO‐Releasing Ruthenium Complexes to Visible Light
Authors: Becker Tobias , Kupfer Stephan , Wolfram Martin , Görls Helmar , Schubert Ulrich S. , Anslyn Eric V. , Dietzek Benjamin , Gräfe Stefanie , Schiller Alexander 
Published: September 2015

AbstractWe report a combined spectroscopical–theoretical investigation on the photosensitization of transition metal nitrosyl complexes. For this purpose, ruthenium nitrosyl complexes based on tetradentate biscarboxamide ligands were synthesized. A crystal structure analysis of a lithium‐based ligand intermediate is described. The Ru complexes have been characterized regarding their photophysical and nitric oxide (NO) releasing properties. Quantum chemical calculations have been performed to unravel the influence of the biscarboxamide ligand frame with respect to the molecular electronic properties of the NO‐releasing pathway. A quantitative measure for the ligand design within photosensitized Ru complexes is introduced and evaluated spectroscopically and theoretically by using time‐dependent density functional theory.
Adding a Structural Context to the Deprotometalation and Trans‐Metal Trapping Chemistry of Phenyl‐Substituted Benzotriazole
Authors: Fuentes M. Ángeles , Kennedy Alan R. , Mulvey Robert E. , Parkinson John A. , Rantanen Toni , Robertson Stuart D. , Snieckus Victor 
Published: September 2015

AbstractOrganometallic bases are becoming increasingly complex, because mixing components can lead to bases superior to single‐component bases. To better understand this superiority, it is useful to study metalated intermediate structures prior to quenching. This study is on 1‐phenyl‐1H‐benzotriazole, which was previously deprotonated by an in situ ZnCl2⋅TMEDA/LiTMP (TMEDA=N,N,N′,N′‐tetramethylethylenediamine; TMP=2,2,6,6‐tetramethylpiperidide) mixture and then iodinated. Herein, reaction with LiTMP exposes the deficiency of the single‐component base as the crystalline product obtained was [{4‐R‐1‐(2‐lithiophenyl)‐1H‐benzotriazole⋅3THF}2], [R=2‐C6H4(Ph)NLi], in which ring opening of benzotriazole and N2 extrusion had occurred. Supporting lithiation by adding iBu2Al(TMP) induces trans‐metal trapping, in which CLi bonds transform into CAl bonds to stabilise the metalated intermediate. X‐ray diffraction studies revealed homodimeric [(4‐R′‐1‐phenyl‐1H‐benzotriazole)2], [R′=(iBu)2Al(μ‐TMP)Li], and its heterodimeric isomer [(4‐R′‐1‐phenyl‐1H‐benzotriazole){2‐R′‐1‐phenyl‐1H‐benzotriazole}], whose structure and slow conformational dynamics were probed by solution NMR spectroscopy.
First N‐Heterocyclic Carbenes Relying on the Triazolone Structural Motif: Syntheses, Modifications and Reactivity
Authors: Jonek Markus , Diekmann Janina , Ganter Christian 
Published: September 2015

Abstract4‐Phenylsemicarbazide and 1,5‐diphenylcarbazide are suitable starting materials for the syntheses of N‐heterocyclic carbene (NHC) compounds with new backbone structures. In the first case, cyclisation and subsequent methylation leads to a cationic precursor whose deprotonation affords the triazolon‐ylidene 2, which was converted to the corresponding sulfur and selenium adducts and a range of metal complexes. In contrast, cyclisation of diphenylcarbazide affords a neutral betain‐type NHC‐precursor 7, which is not in equilibrium with its carbene tautomer 7a. Precursor 7 can either be deprotonated to give the anionic NHC 8 or methylated at the N or O atom of the backbone resulting in two isomeric cationic species 16 and 20. Deprotonation of the latter two provides neutral NHC compounds with a carboxamide or carboximidate backbone, respectively. The ligand properties of the new NHC compounds were evaluated by IR and 77Se NMR spectroscopy. Tolman electronic parameter (TEP) values range from 2050 to 2063 cm−1 with the anionic NHC 8 being the best overall donor.
Bursty event detection from microblog: a distributed and incremental approach
Authors: Li Jianxin , Wen Jianfeng , Tai Zhenying , Zhang Richong , Yu Weiren 
Published: September 2015

SummaryAs a new form of social media, microblogs (e.g., Twitter and Weibo) are playing an important role in people's daily life. With the rise in popularity and size of microblogs, there is a need for distributed approaches that can detect bursty event with low latency from the short‐text data stream. In this paper, we propose a distributed and incremental temporal topic model for microblogs called Bursty Event dEtection (BEE+). BEE+ is able to detect bursty events from short‐text dataset and model the temporal information. And BEE+ processes the post‐stream incrementally to track the topic drifting of events over time. Therefore, the latent semantic indices are preserved from one time period to the next. In order to achieve real‐time processing, we design a distributed execution framework based on Spark engine. To verify its ability to detect bursty event, we conduct experiments on a Weibo dataset of 6,360,125 posts. The results show that BEE+ can outperform the baselines for detecting the meaningful bursty events and track the topic drifting. Copyright © 2015 John Wiley & Sons, Ltd.
Theoretical Study on the Dual Behavior of XeO3 and XeF4 toward Aromatic Rings: Lone Pair–π versus Aerogen–π Interactions
Authors: Bauzá Antonio , Frontera Antonio 
Published: September 2015

AbstractIn this study, several lone pair–π and aerogen–π complexes between XeO3 and XeF4 and aromatic rings with different electronic natures (benzene, trifluorobenzene, and hexafluorobenzene) are optimized at the RI‐MP2/aug‐cc‐pVTZ level of theory. All complexes are characterized as true minima by frequency analysis calculations. The donor/acceptor role of the ring in the complexes is analyzed using the natural bond orbital computational tool, showing a remarkable contribution of orbital interactions to the global stabilization of the aerogen–π complexes. Finally, Bader's AIM analysis of several complexes is performed to further characterize the lone pair–π and aerogen–π interactions.
Carbon, nitrogen, and phosphorus storage in alpine grassland ecosystems of Tibet: effects of grazing exclusion
Authors: Lu Xuyang , Yan Yan , Sun Jian , Zhang Xiaoke , Chen Youchao , Wang Xiaodan , Cheng Genwei 
Published: September 2015

AbstractIn recent decades, alpine grasslands have been seriously degraded on the Tibetan Plateau and grazing exclusion by fencing has been widely adopted to restore degraded grasslands since 2004. To elucidate how alpine grasslands carbon (C), nitrogen (N), and phosphorus (P) storage responds to this management strategy, three types of alpine grassland in nine counties in Tibet were selected to investigate C, N, and P storage in the environment by comparing free grazing (FG) and grazing exclusion (GE) treatments, which had run for 6–8 years. The results revealed that there were no significant differences in total ecosystem C, N, and P storage, as well as the C, N, and P stored in both total biomass and soil (0–30 cm) fractions between FG and GE grasslands. However, precipitation played a key role in controlling C, N, and P storage and distribution. With grazing exclusion, C and N stored in aboveground biomass significantly increased by 5.7 g m−2 and 0.1 g m−2, respectively, whereas the C and P stored in the soil surface layer (0–15 cm) significantly decreased by 862.9 g m−2 and 13.6 g m−2, respectively. Furthermore, the storage of the aboveground biomass C, N, and P was positively correlated with vegetation cover and negatively correlated with the biodiversity index, including Pielou evenness index, Shannon–Wiener diversity index, and Simpson dominance index. The storage of soil surface layer C, N, and P was positively correlated with soil silt content and negatively correlated with soil sand content. Our results demonstrated that grazing exclusion had no impact on total C, N, and P storage, as well as C, N, and P in both total biomass and soil (0–30 cm) fractions in the alpine grassland ecosystem. However, grazing exclusion could result in increased aboveground biomass C and N pools and decreased soil surface layer (0–15 cm) C and P pools.
Some strategies for the stabilization of long chain n‐3 PUFA‐enriched foods: A review
Authors: Jacobsen Charlotte 
Published: September 2015

Oil‐in‐water (o/w) and water‐in‐oil (w/o) emulsions are important colloid structures in food products, as many foods exist as emulsions. O/w emulsions, such as milk, mayonnaise, and salad dressing constitute a particularly large—and widely consumed—group of such complex, heterophasic food systems. Lipid oxidation is one of the major quality deteriorating problems in such foods. This is due to the fact that lipid oxidation is an interfacial phenomenon and since emulsions have a large interfacial area they are particularly susceptible to oxidation. Lipid oxidation is induced by transition metals, light, temperature, oxygen, and is also affected by pH, droplet size, and numerous other factors related to the composition of the emulsion. During the last decade, marine polyunsaturated n‐3 polyunsaturated fatty acids (PUFA) have increasingly been incorporated into emulsified foods in order to address recent nutritional recommendations. The increased use of n‐3 PUFA has resulted in new challenges for the food industry with respect to avoiding lipid oxidation. This review provides an overview of results obtained primarily in the author's own lab on the use of the following different strategies to reduce or inhibit lipid oxidation by: (1) optimizing the processing conditions; (2) utilizing n‐3 PUFA delivery systems; and (3) addition of antioxidants.Practical applications:This review provides an overview of how food producers can inhibit or reduce lipid oxidation in various real foods enriched with n‐3 PUFA. Particular emphasis are not only on emulsified foods, such as mayonnaise, dressing, milk, and yoghurt drink, but solid foods, such as energy bars, fish paté, and cakes are also touched upon. For emulsified foods, it is possible to reduce lipid oxidation by optimizing homogenization conditions (pressure and temperature) and the type of homogenization equipment can also affect lipid oxidation. The use of fish‐oil‐in water emulsions as an n‐3 PUFA delivery system can reduce lipid oxidation in some cases, but the delivery system must be optimized for the food system in question. Finally, lipid oxidation can also be reduced by antioxidants. The review suggests that multi‐component antioxidants with multi‐function properties in many cases may provide better efficacy than mono‐compound antioxidants.Lipid oxidation of n‐3 PUFA enriched food emulsions leads to formation of undesirable off‐flavors. Possible stabilization strategies include: Optimization of homogenization conditions, use of n‐3 PUFA delivery emulsions or antioxidant addition. Efficacy of antioxidants can be improved by designing antioxidants with the optimal molecular structure.
Ireland–Claisen Rearrangement of 6‐Methylene‐1,4‐oxazepan‐2‐ones
Authors: Smits Gints , Kinens Artis , Zemribo Ronalds 
Published: September 2015

AbstractThe Ireland–Claisen rearrangement of 6‐methylene‐1,4‐oxazepan‐2‐one‐derived boron enolates leads to stereochemically defined, synthetically useful 4‐(E)‐ethylidene prolines. Detailed computational and experimental studies explain the stereochemical outcome of this transformation and suggest an unusual double‐chelated transition state that involves two boron atoms. The scope of the method is also explored.
Highly Selective and Sensitive Voltammetric Sensor Based on Ruthenium Nanoparticle Anchored Calix[4]amidocrown‐5 Functionalized Reduced Graphene Oxide: Simultaneous Determination of Quercetin, Morin and Rutin in Grape Wine
Authors: Elçin Serkan , Yola Mehmet Lütfi , Eren Tanju , Girgin Burcu , Atar Necip 
Published: September 2015

AbstractIn this report, ruthenium nanoparticles (RuNPs) and calix[4]amidocrown‐5 (C4A5) were synthesized and grafted onto the surface of reduced graphene oxide (RGO) nanocomposite (RuNPs/C4A5/RGO). The morphologies of the nanocomposites were characterized by transmission electron microscope, scanning electron microscope, atomic force microscope, electrochemical impedance spectroscopy and x‐ray photoelectron spectroscopy. The electrochemical experiments were performed by cyclic voltammetry, electrochemical impedance spectroscopy and square wave voltammetry. The simultaneous determination of quercetin, rutin and morin was performed on glassy carbon electrode modified with RuNPs/C4A5/RGO (RuNPs/C4A5/RGO/GCE). The linearity ranges and the detection limits of QR, RT and MR were 1.0×10−10–1.0×10−8 M and 2.0×10−11 M respectively.
The Role of Microfabrication and Nanotechnology in the Development of Microbial Fuel Cells
Authors: Rojas Jhonathan Prieto , Hussain Muhammad M. 
Published: September 2015

AbstractInnovative solutions are paramount to the identification and development of alternative energy resources, specifically for the production of potable water. Microbial fuel cells (MFCs) are a trending emerging technology that promises green energy production while simultaneously treating wastewater. At present, several research efforts are working towards determining which bacteria, fuels, and materials are optimal for developing the most efficient MFCs; microsized MFCs have a key role in this goal. Therefore, in this Review, we summarize recent microfabrication techniques for building microsized cells and elaborate on their advantages and the challenges that need to be overcome. We will then focus on the integration of nanomaterials into MFCs and finish with an overview on the challenges to scale up MFCs and potential uses for these miniature cells.
Body Contouring After Bariatric Surgery
Authors: Ellison Jo M. , Steffen Kristine J. , Sarwer David B. 
Published: September 2015

AbstractIndividuals who undergo bariatric surgery generally experience rapid and dramatic weight loss. While the weight loss typically confers significant health benefits, an undesirable consequence is often excessive quantities of hanging, surplus skin. Some patients undergo body‐contouring surgery (BCS) in order to improve health, mobility, appearance and psychological adjustment. While the majority of post‐bariatric patients desire BCS in one or more body regions, a small percentage of patients receive such surgeries. Lack of knowledge about procedures, cost and (in the USA and several other countries) difficulty obtaining insurance reimbursement likely prevents many patients from undergoing BCS. Those who do undergo BCS appear to be at heightened risk for wound‐healing complications. Despite these complications, the majority of patients report satisfactory BCS outcomes. The extant literature in this area provides a great deal of information about these issues; nevertheless, additional research is needed to further inform clinical management and improve patient outcomes. Copyright © 2015 John Wiley & Sons, Ltd and Eating Disorders Association.
Copper status of exposed microorganisms influences susceptibility to metallic nanoparticles
Authors: Reyes Vincent C. , Spitzmiller Melissa R. , Hong-Hermesdorf Anne , Kropat Janette , Damoiseaux Robert D. , Merchant Sabeeha S. , Mahendra Shaily 
Published: September 2015

Abstract

Although interactions of metallic nanoparticles (NPs) with various microorganisms have been previously explored, few studies have examined how metal sensitivity impacts NP toxicity. The present study investigated the effects of copper NPs (Cu-NP) exposure on the model alga Chlamydomonas reinhardtii in the presence and absence of the essential micronutrient copper. The toxic ranges for Cu-NPs and the ionic control, CuCl2, were determined using a high-throughput adenosine triphosphate (ATP)-based fluorescence assay. The Cu-NPs caused similar mortality in copper-replete and copper-deplete cells (median inhibitory concentration [IC50]: 14–16 mg/L) but were less toxic than the ionic control, CuCl2 (IC50: 7 mg/L). Using this concentration range, the Cu-NP impacts on cell morphology, copper accumulation, chlorophyll content, and expression of stress genes under both copper supply states were assessed. Osmotic swelling, membrane damage, and chloroplast and organelle disintegration were observed by transmission electron microscopy at both conditions. Despite these similarities, copper-deplete cells showed greater accumulation of loosely bound and tightly bound copper after exposure to Cu-NPs. Furthermore, copper-replete cells experienced greater loss of chlorophyll content, 19% for Cu-NPs, compared with only an 11% net decrease in copper-deplete cells. The tightly bound copper was bioavailable as assessed by reverse-transcriptase quantitative polymerase chain reaction analysis of CYC6, a biomarker for Cu deficiency. The increased resistance of copper-deplete cells to Cu-NPs suggests that these cells potentially metabolize excess Cu-NPs or better manage sudden influxes of ions. The results suggest that toxicity assessments must account for the nutritional status of impacted organisms and use toxicity models based on estimations of the bioavailable fractions. Environ Toxicol Chem 2016;35:1148–1158. © 2015 SETAC
Dynamic greedy routing in overlay networks using virtual coordinates from the hyperbolic plane
Authors: Magoni Damien , Cassagnes Cyril 
Published: September 2015

AbstractGreedy routing algorithms based on virtual coordinates have attracted considerable interest in recent years. Those based on coordinates taken from the hyperbolic plane have interesting theoretical scalability properties. However, their scalability and reliability are yet to be ensured when applied to large‐scale dynamic networks. In this paper, we propose a scalable and reliable solution for creating and managing dynamic overlay networks where nodes have hyperbolic coordinates. In this context, our solution provides a greedy routing algorithm based on the hyperbolic distance. To cope with network dynamics, we have defined two methods for avoiding temporary local minima and one method for maintaining the greedy embedding over time. Through analysis, we evaluate the complexity costs of our solution. Through simulations, we assess the scalability of our solution on static networks and its reliability on dynamic networks. Results show that using our solution based on hyperbolic geometry provides scalability and reliability to both addressing and routing tasks in dynamic overlay networks. Copyright © 2015 John Wiley & Sons, Ltd.
Effect of green Spanish‐style Manzanilla packaging conditions on the prevalence of the putative probiotic bacteria Lactobacillus pentosus TOMC‐LAB2
Authors: Rodríguez‐Gómez Francisco , Romero‐Gil Verónica , García‐García Pedro , Arroyo‐López Francisco Noé , Garrido‐Fernández Antonio 
Published: September 2015

AbstractThis work focuses on the persistence of the putative probiotic bacteria Lactobacillus pentosus TOMC‐LAB2 on green Spanish‐style Manzanilla olives according to different packaging conditions and storage temperatures. The lactic acid bacteria population decreased with time but the highest survival counts (and lowest yeasts) at the end of storage (8 months) were observed in plastic pouches under nitrogen atmosphere and glass jars with brine stored at 20°C. Molecular techniques showed a 100% presence of the putative probiotic bacteria in biofilms adhered to olive epidermis, while it was absent in PPB (plastic pouches with brine) and in olives stored at 7°C. No changes in NaCl, pH or combined acidity were observed during the storage except for a slight increase in titratable acidity at 20°C. The color of the fruits was stable but degraded at 20°C for olives in plastic pouches with brine.