bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of the Stable Ordered Conjugated Polymer Poly(dibromodiacetylene) from an Explosive Monomer
Authors: Jin Hongjian , Young Christopher N. , Halada Gary P. , Phillips Brian L. , Goroff Nancy S. 
Published: October 2015

AbstractDibromobutadiyne is an extremely unstable compound that explodes at room temperature, even under inert atmosphere. This instability has limited the studies of dibromobutadiyne almost entirely to spectroscopic characterization. Here we report an approach to control the reactivity of dibromobutadiyne, via topochemical reaction in cocrystals, leading to the ordered polymer poly(dibromodiacetylene), PBDA. At low temperatures (−15 to −18 °C), dibromobutadiyne can form cocrystals with oxalamide host molecules containing either pyridyl or nitrile side groups, in which halogen bonds align the dibromobutadiyne monomers for topochemical polymerization. The cocrystals with the bis(nitrile) oxalamide host undergo complete ordered polymerization to PBDA, demonstrated by solid‐state MAS‐NMR, Raman, and optical absorption spectroscopy. Once formed, the polymer can be separated from the host; unlike the monomer, PBDA is stable at room temperature.
Ceria–Zirconia Particles Wrapped in a 2D Carbon Envelope: Improved Low‐Temperature Oxygen Transfer and Oxidation Activity
Authors: Aneggi Eleonora , Rico‐Perez Veronica , de Leitenburg Carla , Maschio Stefano , Soler Lluís , Llorca Jordi , Trovarelli Alessandro 
Published: October 2015

AbstractEngineering the interface between different components of heterogeneous catalysts at nanometer level can radically alter their performances. This is particularly true for ceria‐based catalysts where the interactions are critical for obtaining materials with enhanced properties. Here we show that mechanical contact achieved by high‐energy milling of CeO2–ZrO2 powders and carbon soot results in the formation of a core of oxide particles wrapped in a thin carbon envelope. This 2D nanoscale carbon arrangement greatly increases the number and quality of contact points between the oxide and carbon. Consequently, the temperatures of activation and transfer of the oxygen in ceria are shifted to exceptionally low temperatures and the soot combustion rate is boosted. The study confirms the importance of the redox behavior of ceria‐zirconia particles in the mechanism of soot oxidation and shows that the organization of contact points at the nanoscale can significantly modify the reactivity resulting in unexpected properties and functionalities.
High‐Resolution Crystal Structure of a Silver(I)–RNA Hybrid Duplex Containing Watson–Crick‐like CSilver(I)C Metallo‐Base Pairs
Authors: Kondo Jiro , Tada Yoshinari , Dairaku Takenori , Saneyoshi Hisao , Okamoto Itaru , Tanaka Yoshiyuki , Ono Akira 
Published: October 2015

AbstractMetallo‐base pairs have been extensively studied for applications in nucleic acid‐based nanodevices and genetic code expansion. Metallo‐base pairs composed of natural nucleobases are attractive because nanodevices containing natural metallo‐base pairs can be easily prepared from commercially available sources. Previously, we have reported a crystal structure of a DNA duplex containing THgIIT base pairs. Herein, we have determined a high‐resolution crystal structure of the second natural metallo‐base pair between pyrimidine bases CAgIC formed in an RNA duplex. One AgI occupies the center between two cytosines and forms a CAgIC base pair through N3AgIN3 linear coordination. The CAgIC base pair formation does not disturb the standard A‐form conformation of RNA. Since the CAgIC base pair is structurally similar to the canonical Watson–Crick base pairs, it can be a useful building block for structure‐based design and fabrication of nucleic acid‐based nanodevices.
Renewable Feedstocks: The Problem of Catalyst Deactivation and its Mitigation
Authors: Lange Jean‐Paul 
Published: October 2015

AbstractMuch research has been carried out in the last decade to convert bio‐based feedstock into fuels and chemicals. Most of the research focuses on developing active and selective catalysts, with much less attention devoted to their long‐term stability. This Review considers the main challenges in long‐term catalyst stability, discusses some fundamentals, and presents options for their mitigation. Three main challenges are discussed: catalyst fouling, catalyst poisoning, and catalyst destruction. Fouling is generally related to the deposition of insoluble components present in the feed or formed by degradation of the feed or intermediates. Poisoning is related to the deposition of electropositive contaminants (e.g. alkali and alkaline earth metals) on acid sites or of electronegative contaminants (e.g. N and S) at hydrogenation sites. Catalyst destruction results from the thermodynamic instability of most oxidic supports, solid acids/bases, and hydrogenation functions under hydrothermal conditions.
Effect of the maleation of lignosulfonate on the mechanical and thermal properties of lignosulfonate/poly(ε‐caprolactone) blends
Authors: Wang Fei , Yang Xuping , Zou Yangxue 
Published: October 2015

ABSTRACTMaleated lignosulfonate (MLS) produced by esterification with maleic anhydride and unmodified lignosulfonate [in the form of lignosulfonic acid (LS)] were incorporated into poly(ε‐caprolactone) (PCL) via melt‐blending. The obtained MLS/PCL composites and LS/PCL composites were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, and electronic universal testing. The FTIR and DSC results show that the interactions between MLS and PCL were stronger than those between LS and PCL, whereas the TG analysis indicated that the LS/PCL composite was more thermally stable than the MLS/PCL composite. The tensile strength of the MLS/PCL blends remained at about 18 MPa when the MLS content reached 50 wt %; this was about 1.7 times larger than that of the LS/PCL blend. The Young's modulus was also enhanced; this indicated an improvement in the mechanical properties. The results show that the maleation of lignosulfonate was beneficial for enhancing the mechanical properties of these blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42925.
Effect of pigmentation on polyurethane/polysiloxane hybrid coatings
Authors: Gao Tongzhai , Maya‐Visuet Enrique , He Zhouying , Castaneda‐Lopez Homero , Zvonkina Irina J. , Soucek Mark D. 
Published: October 2015

ABSTRACTRutile TiO2 was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the influence of pigmentation on the inorganic phase of the hybrid coatings. Two urethanes were prepared from the isocyanurate of hexane diisocyanate (HDI), alkoxysilane modified HDI, and tetraethyl orthosilicate (TEOS) oligomers, with oligoesters derived from either cyclohexane diacids (CHDA) and 2‐butyl‐2‐ethyl‐1,3‐propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6‐hexanediol (HD), and trimethylol propane (TMP). The oligoesters were spectroscopically characterized using GPC, FT‐IR, and NMR. Chemical interaction between the TiO2 and the sol–gel precursor was investigated using solid‐state 29Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings are evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment was observed to be well dispersed in the polymer binder. The thermal stability, the tensile modulus, and strength of the coatings were enhanced with increasing PVC, whereas the pull‐off adhesion and flexibility (elongation‐at‐break) were reduced with increasing PVC. Finally, the pigmented coatings were evaluated by electrochemical impedance spectroscopy (EIS) and the results showed that 10 wt % of the pigment improved the corrosion resistance of the entire coating system. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42947.
Novel dynamic model for aerated shaking bioreactors
Authors: Tabrizi Hamed Osouli , Amoabediny Ghassem , Moshiri Behzad , Haji Abbas Mahdi Pesaran , Pouran Behdad , Imenipour Emad , Rashedi Hamid , Büchs Jochen 
Published: October 2015

AbstractA novel mathematical model of aerated shaking bioreactors is developed and its accuracy is evaluated with experimental data. Corynebacterium glutamicum (DM 1730) and Arxula adeninivorans (WT LS3) are used as model microorganisms. In order to get the experimental data, shake flasks of 250 mL and filling volume of 15 mL, together with online measurement tools for measuring oxygen transfer rate and tools for measuring dry biomass concentration, are used. This mathematical model may be regarded as a key tool for computational simulations or developing model‐based control approaches for necessary automation and optimization purposes. Moreover, the error evaluation presented in this paper should be taken into account when using the model. The squared Pearson product‐moment correlation coefficient (r2) and average deviation of error are used as two statistical criteria to quantify the accuracy and consistency of the model. The r2 for biomass concentration equals 0.95 for C. glutamicum (DM 1730) and 0.93 for A. adeninivorans (WT LS3). The reported average deviation of error of biomass concentration approaches 17.4% for C. glutamicum (DM 1730) and 26.7% for A. adeninivorans (WT LS3).
Toward regeneration of articular cartilage
Authors: Iwamoto Masahiro , Ohta Yoichi , Larmour Colleen , Enomoto‐Iwamoto Motomi 
Published: October 2015

AbstractArticular cartilage is classified as permanent hyaline cartilage and has significant differences in structure, extracelluar matrix components, gene expression profile, and mechanical property from transient hyaline cartilage found in the epiphyseal growth plate. In the process of synovial joint development, articular cartilage originates from the interzone, developing at the edge of the cartilaginous anlagen, and establishes zonal structure over time and supports smooth movement of the synovial joint through life. The cascade actions of key regulators, such as Wnts, GDF5, Erg, and PTHLH, coordinate sequential steps of articular cartilage formation. Articular chondrocytes are restrictedly controlled not to differentiate into a hypertrophic stage by autocrine and paracrine factors and extracellular matrix microenvironment, but retain potential to undergo hypertrophy. The basal calcified zone of articular cartilage is connected with subchondral bone, but not invaded by blood vessels nor replaced by bone, which is highly contrasted with the growth plate. Articular cartilage has limited regenerative capacity, but likely possesses and potentially uses intrinsic stem cell source in the superficial layer, Ranvier's groove, the intra‐articular tissues such as synovium and fat pad, and marrow below the subchondral bone. Considering the biological views on articular cartilage, several important points are raised for regeneration of articular cartilage. We should evaluate the nature of regenerated cartilage as permanent hyaline cartilage and not just hyaline cartilage. We should study how a hypertrophic phenotype of transplanted cells can be lastingly suppressed in regenerating tissue. Furthermore, we should develop the methods and reagents to activate recruitment of intrinsic stem/progenitor cells into the damaged site. Birth Defects Research (Part C) 99:192–202, 2013. © 2013 Wiley Periodicals, Inc.
Quantifizierung von DNA durch Absorptionsmessung
Authors: Hauk Andrea 
Published: October 2015

AbstractDie Konzentration von Nukleinsäuren in Lösung lässt sich durch die Messung der UV‐Absorption bei 260nm im Photometer bestimmen. Hierzu füllt man die zu messende Probe in eine Küvette und setzt diese in den Strahlengang des Photometers ein. Dort wird gemessen, wieviel Licht der Wellenlänge 260nm von den Nukleinsäuren in der Probe absorbiert und wieviel durchgelassen wird. Das Ergebnis wird als “Extinktion” angezeigt. Doch wie errechnet sich aus diesem Wert die Konzentration der DNA in der Probe? Und worauf sollte man bei der Messung achten, um ein genaues Ergebnis zu erhalten?
Kinetic Study on Reactions of O‐Y‐substituted Phenyl Thionobenzoates with Quinuclidine: Factors Governing Reactivity and Reaction Mechanism
Authors: Yang Eun‐Ji , Kim Min‐Young , Um Ik‐Hwan 
Published: October 2015

Second‐order rate constants (k
quin) for the reactions of O‐Y‐substituted phenyl thionobenzoates (3a–3i) with quinuclidine have been measured spectrophotometrically. Comparison of k
quin with the rate constants reported previously for the corresponding reactions with benzylamine (k
BzNH2) has revealed that quinuclidine is less reactive than benzylamine toward 3a–3i although the former is 2.1 pK
a units more basic than the latter. Steric hindrance exerted by quinuclidine has been suggested to be responsible for the decreased reactivity of the tertiary amine. The Brønsted‐type plot for the reactions of 3a–3i with quinuclidine is linear with βlg = −0.37. The Hammett plot correlated with constants exhibits many scattered points (
R
2
= 0.982). In contrast, the Yukawa‐Tsuno plot results in an excellent linear correlation (
R
2
= 0.9992) with ρ
Y
= 0.96 and r = 0.51, indicating that a negative charge develops partially on the O atom of the leaving group. Thus, the reactions of 3a–3i with quinuclidine have been concluded to proceed through a concerted mechanism in which expulsion of the leaving group is advanced only a little in the rate‐determining transition state.
Synthesis of Novel Ligustrazine Derivatives as Na+/H+ Exchange Inhibitors
Authors: Ren Mei , Dong Jin , Xu Yungen , Wen Nan , Gong Guoqing 
Published: October 2015

AbstractA novel series of 3,5,6‐trimethylpyrazine‐2‐methoxy (or methylamino) substituted benzoyl‐guanidine derivatives were designed and synthesized as Na+/H+ exchange (NHE) inhibitors. In this study, compounds with electron‐withdrawing substituents on the benzene ring seemed to improve NHE‐1 inhibitory activities. Compounds 6d, 6k, and 6l were found to be potent inhibitors of NHE‐1 (IC50=3.0±1.6, 3.0±1.4, and 1.6±0.4 nmol/l, resp.). Furthermore, they showed a remarkable reduction of infarct size in the rat myocardial infarction model in vivo.
Activity of Six Essential Oils Extracted from Tunisian Plants against Legionella pneumophila
Authors: Chaftar Naouel , Girardot Marion , Quellard Nathalie , Labanowski Jérôme , Ghrairi Tawfik , Hani Khaled , Frère Jacques , Imbert Christine 
Published: October 2015

AbstractThe aim of this study was to investigate the composition of six essential oils extracted from Tunisian plants, i.e., Artemisia herba‐alba Asso, Citrus sinensis (L.) Osbeck, Juniperus phoenicea L., Rosmarinus officinalis L., Ruta graveolens L., and Thymus vulgaris L., and to evaluate their activity against Legionella pneumophila (microdilution assays). Eight Legionella pneumophila strains were studied, including the two well‐known serogroup 1 Lens and Paris strains as controls and six environmental strains isolated from Tunisian spas belonging to serogroups 1, 4, 5, 6, and 8. The essential oils were generally active against L. pneumophila. The activities of the A. herba‐alba, C. sinensis, and R. officinalis essential oils were strain‐dependent, whereas those of the J. phoenicea and T. vulgaris oils, showing the highest anti‐Legionella activities, with minimum inhibitory concentrations (MICs) lower than 0.03 and lower than or equal to 0.07 mg/ml, respectively, were independent of the strains' serogroup. Moreover, the microorganisms treated with T. vulgaris essential oil were shorter, swollen, and less electron‐dense compared to the untreated controls. Isoborneol (20.91%), (1S)‐α‐pinene (18.30%) β‐phellandrene (8.08%), α‐campholenal (7.91%), and α‐phellandrene (7.58%) were the major components isolated from the J. phoenicea oil, while carvacrol (88.50%) was the main compound of the T. vulgaris oil, followed by p‐cymene (7.86%). This study highlighted the potential interest of some essential oils extracted from Tunisian plants as biocides to prevent the Legionella risk.
Short Proline‐Rich Antimicrobial Peptides Inhibit Either the Bacterial 70S Ribosome or the Assembly of its Large 50S Subunit
Authors: Krizsan Andor , Prahl Caroline , Goldbach Tina , Knappe Daniel , Hoffmann Ralf 
Published: October 2015

AbstractShort proline‐rich antimicrobial peptides (PrAMPs) are a promising class of antibiotics that use novel mechanisms, thus offering the potential to overcome the health threat of multiresistant pathogens. The peptides bind to the bacterial 70S ribosome and can inhibit protein translation. We report that PrAMPs can be divided into two classes, with each class binding to a different site, and thus use different lethal mechanisms. Oncocin‐type peptides inhibit protein translation inEscherichia coliby binding to the exit tunnel of the 70S ribosome with half maximal inhibitory concentrations (IC50values) of around 2 to 6 μmol L−1, whereas apidaecin‐type peptides block the assembly of the large (50S) subunit of the ribosome, resulting in similar IC50values. The revealed mechanisms should allow the design of new antibiotics to overcome current bacterial resistance mechanisms.
Solid‐State Bipolar Electrochemistry: Polymer‐Based Light‐Emitting Electrochemical Cells
Authors: Chen Shulun , Wantz Guillaume , Bouffier Laurent , Gao Jun 
Published: October 2015

AbstractWe present solid‐state, polymer‐based, light‐emitting electrochemical cells incorporating bipolar electrodes (BPEs) positioned between the driving electrodes. The dominant processes in these planar electrochemical cells are in situ electrochemical p and n doping of the luminescent conjugated polymer when a sufficient voltage bias is applied between the feeder anode and cathode. The inclusion of floating BPEs causes additional doping at the extremities of the BPE, which has been visualized through in situ fluorescence imaging. We investigate how the applied voltage bias and the BPE size affect electrochemical doping from the BPE. We observe an interesting delay in the appearance of doping from the BPE if the applied voltage bias was initially insufficient. Doping eventually occurs when the potential difference across the BPE/polymer interface becomes sufficient, as doping from the driving electrodes propagates. The inclusion of BPEs can lead to more efficient polymer light‐emitting and photovoltaic cells when a large number of active junctions are formed.
Direct Grafting of Free‐Base meso‐Triarylporphyrins on Electrode Materials through Diazonium Reduction: Reversible Zinc(II) Metallation of the Resulting Materials
Authors: Hebié Seydou , Devillers Charles H. , Fournier Sophie , Lucas Dominique 
Published: October 2015

AbstractElectroreduction of free base meso‐diazonium‐triarylporphyrins, generated in situ from their corresponding meso‐aminotriarylporphyrin precursors, leads to the formation of a covalently grafted porphyrin film. In this new material, contrary to recently published results, the free base porphyrin core is directly bonded to the surface, that is, without any spacer such as phenyl fragments. These thin films are characterized by cyclic voltammetry (CV), UV/Vis absorption spectroscopy and water angle contact. The electrochemical response is in agreement with a multilayer structure. Efficient and reversible zinc metallation of the immobilized porphyrin units is readily achieved opening the door to numerous applications in sensing and electrocatalysis.
Photodriven Multi‐electron Storage in Disubstituted RuIIDppz Analogues
Authors: Aslan Joseph M. , Boston David J. , MacDonnell Frederick M. 
Published: October 2015

AbstractFour derivatives of the laminate acceptor ligand dipyrido‐[3,2‐a:2′,3′‐c]phenazine (dppz) and their corresponding ruthenium complexes, [Ru(phen)2(dppzX2)]2+, were prepared and characterized by NMR spectroscopy, ESI‐MS, and elemental analysis. The new ligands, generically denoted dppzX2, were symmetrically disubstituted on the distal benzene ring to give 10,13‐dibromodppz (dppz‐p‐Br), 11,12‐dibromodppz (dppz‐o‐Br), 10,13‐dicyanodppz (dppz‐p‐CN), 11,12‐dicyanodppz (dppz‐o‐CN). Solvated ground state MO calculations of the ruthenium complexes reveal that these electron‐withdrawing substituents not only lower the LUMO of the dppz ligand (dppz(CN)2<dppzBr2<dppz), but that theparadisubstitution results in a lower LUMO than theorthodisubstitution (dppz‐p‐CN<(dppz‐o‐CN), and dppz‐p‐Br<dppz‐o‐Br). The validity of the calculations was confirmed experimentally using cyclic voltammetry. Of the complexes evaluated in this study, only the dicyanodppz complexes showed multiple dppz‐based reductions prior to reduction of the phen ligands. The capacity to form singly and doubly reduced dppz‐based anions at modest reduction potentials was confirmed using a combination of spectroelectrochemical and chemical titration methods. When subjected to photolysis with visible light in the presence of a sacrificial donor, such as triethylamine, both cyano complexes showed multi‐electron reduction. The other complexes only show a single reduction.
Unmasking the Action of Phosphinous Acid Ligands in Nitrile Hydration Reactions Catalyzed by Arene–Ruthenium(II) Complexes
Authors: Tomás‐Mendivil Eder , Cadierno Victorio , Menéndez María I. , López Ramón 
Published: October 2015

AbstractThe catalytic hydration of benzonitrile and acetonitrile has been studied by employing different arene–ruthenium(II) complexes with phosphinous (PR2OH) and phosphorous acid (P(OR)2OH) ligands as catalysts. Marked differences in activity were found, depending on the nature of both the P‐donor and η6‐coordinated arene ligand. Faster transformations were always observed with the phosphinous acids. DFT computations unveiled the intriguing mechanism of acetonitrile hydration catalyzed by these arene–ruthenium(II) complexes. The process starts with attack on the nitrile carbon atom of the hydroxyl group of the P‐donor ligand instead of on a solvent water molecule, as previously suggested. The experimental results presented herein for acetonitrile and benzonitrile hydration catalyzed by different arene–ruthenium(II) complexes could be rationalized in terms of such a mechanism.
Enantioselective Total Synthesis of Secalonic Acid E
Authors: Ganapathy Dhandapani , Reiner Johannes R. , Löffler Lorenz E. , Ma Ling , Gnanaprakasam Boopathy , Niepötter Benedikt , Koehne Ingo , Tietze Lutz F. 
Published: October 2015

AbstractThe first enantioselective synthesis of a secalonic acid containing a dimeric tetrahydroxanthenone skeleton is described, using a Wacker‐type cyclization of a methoxyphenolic compound to form a chiral chroman with a quaternary carbon stereogenic center with >99 % ee. Further steps are a Sharpless dihydroxylation and a Dieckmann condensation to give a tetrahydroxanthenone. A late‐stage one‐pot palladium‐catalyzed Suzuki‐dimerization reaction leads to the 2,2′‐biphenol linkage to complete the enantioselective total synthesis of secalonic acid E in 18 steps with 8 % overall yield.
ChemInform Abstract: Synthesis and Crystal Structure of Ba26B12Si5N27 Containing [Si2] Dumbbells.
Authors: Takayuki Hashimoto , Yamane Hisanori , Becker Nils , Dronskowski Richard 
Published: October 2015

AbstractSingle crystals of Ba26B12Si5N27 are grown from a 1:0.5:0.25:3.6 molar mixture of Ba, Si, La, and Na on the wall of a BN crucible (BN crucible in stainless steel tube, 900 °C, 2 h; cooling to 300 °C at a rate of 4 °C/h).
ChemInform Abstract: Pb17O8Cl18: A Promising IR Nonlinear Optical Material with Large Laser Damage Threshold Synthesized in an Open System.
Authors: Zhang Hui , Zhang Min , Pan Shilie , Dong Xiaoyu , Yang Zhihua , Hou Xueling , Wang Zheng , Chang Kelvin B. , Poeppelmeier Kenneth R. 
Published: October 2015

AbstractHigh‐quality single crystals of Pb17O8Cl18 with sizes of up to 7 mm x 2 mm x 2 mm are grown from a stoichiometric melt of PbO and PbCl2 (430 °C, 48 h) by a modified crystallization method in an open system.