bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bestimmung von Strukturinformation aus experimentellen Messdaten für Biomoleküle
Authors: van Gunsteren Wilfred F. , Allison Jane R. , Daura Xavier , Dolenc Jožica , Hansen Niels , Mark Alan E. , Oostenbrink Chris , Rusu Victor H. , Smith Lorna J. 
Published: November 2016

AbstractWährend des letzten halben Jahrhunderts hat die Anzahl und die Genauigkeit von experimentellen Verfahren, welche imstande sind, Werte von beobachtbaren Größen für biomolekulare Systeme zu liefern, stetig zugenommen. Die Umwandlung eines Messwerts Qexp einer beobachtbaren Größe Q in strukturelle Information stellt jedoch eine Aufgabe dar, welche theoretische und praktische Probleme mit sich bringt: 1) mangelhafte oder ungenaue Werte Qexp, 2) Ungenauigkeiten im verwendeten funktionalen Zusammenhang
, zur Verknüpfung der Größe Q mit der Struktur
, 3) die Beschreibung der messungsinhärenten Mittelung von Qexp, 4) die Handhabung einer mehrdeutigen Umkehrfunktion
zur Funktion
, um nur einige zu nennen. Diese Problemstellungen treffen auf eine Vielzahl beobachtbarer Größen Q und Messverfahren zu, wie z. B. Röntgen‐ und Neutronenbeugung, Kleinwinkel‐ und Weitwinkel‐Röntgenstreuung, Bildgebung mittels Freier‐Elektronen‐Laser, Kryo‐Elektronenmikroskopie, Kernspinresonanz, paramagnetische Elektronenresonanz, Infrarot‐ und Raman‐Spektroskopie, Zirkulardichroismus, Förster‐Resonanz‐Energietransfer, Rasterkraftmikroskopie und Ionenmobilitäts‐Massenspektrometrie. Das Vorgehen, Strukturinformation aus Messdaten zu gewinnen, wird anhand von Beispielen aus der Literatur, welche die Auswirkungen der vielfältigen zu treffenden Entscheidungen und Näherungen aufzeigen, besprochen. Die Ausführungen richten sich dabei in erster Linie an Nichtexperten und Anfänger auf dem Gebiet. Eine Auflistung an Entscheidungen, die es zu vermeiden gilt, wird bereitgestellt.
Decarboxylative [4+2] Cycloaddition by Synergistic Palladium and Organocatalysis
Authors: Leth Lars A. , Glaus Florian , Meazza Marta , Fu Liang , Thøgersen Mathias K. , Bitsch Emma A. , Jørgensen Karl Anker 
Published: November 2016

AbstractA novel reaction based on synergistic catalysis, combining palladium‐ and organocatalysis has been developed. The palladium catalyst activates vinyl benzoxazinanones via a decarboxylation to undergo a [4+2] cycloaddition with iminium‐ion activated α,β‐unsaturated aldehydes. The reaction is demonstrated to proceed for a number of combinations of vinyl benzoxazinanones reacting with α,β‐unsaturated aldehydes, providing highly substituted vinyl tetrahydroquinolines in good to high yields, and excellent enantio‐ and diastereoselectivities (>98 % ee and >20:1 d.r.). The palladium catalyst used in the synergistic catalysis can be re‐used in a one‐pot sequential coupling reaction with an aromatic boronic acid forming the coupling product in 95 % yield, >20:1 d.r. and 99 % ee.
Sugar–Edge Interactions in a DNA–RNA G‐Quadruplex: Evidence of Sequential C−H⋅⋅⋅O Hydrogen Bonds Contributing to RNA Quadruplex Folding
Authors: Dickerhoff Jonathan , Appel Bettina , Müller Sabine , Weisz Klaus 
Published: November 2016

AbstractDNA G‐quadruplexes were systematically modified by single riboguanosine (rG) substitutions at anti‐dG positions. Circular dichroism and NMR experiments confirmed the conservation of the native quadruplex topology for most of the DNA–RNA hybrid structures. Changes in the C8 NMR chemical shift of guanosines following rG substitution at their 3′‐side within the quadruplex core strongly suggest the presence of C8−H⋅⋅⋅O hydrogen‐bonding interactions with the O2′ position of the C2′‐endo ribonucleotide. A geometric analysis of reported high‐resolution structures indicates that such interactions are a more general feature in RNA quadruplexes and may contribute to the observed preference for parallel topologies.
Preparation and characterization of soluble bismaleimide‐triazine resins based on asymmetric bismaleimide
Authors: Ren Zhidong , Cheng Yuanrong , Li Yan , Xiao Fei 
Published: November 2016

ABSTRACTA series of bismaleimide‐triazine resins (EBT) were prepared from 2‐(4′‐maleimido)phenyl‐2‐(4′‐maleimidophenoxyl)phenylbutane (EBA‐BMI) and 2,2‐bis(4‐cyanatophenyl)propane (BADCy). The resins show attractive processability with good solubility in low boiling point solvents and wide processing temperature windows. Introduction of diallylbisphenol A (DBA) can decrease the curing temperature of EBT resins that the curing exothermic peak temperature shifted from 291 to 237 °C as the content of DBA increased from 0 to 20%. The curing condition influenced the thermal properties of the cured EBT resins. The glass transition temperature increased as the curing temperature and curing time increased. The cured EBT resins show high glass transition temperature up to 352 °C, high thermal stability with 5% weight loss temperature over 405 °C, low coefficient of thermal expansion about 45 to 52 ppm/°C, and high storage modulus up to 2.6 GPa at 250 °C. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44519.
In situ formed internal water channels improving water swelling and mechanical properties of water swellable rubber composites
Authors: Dehbari Nazila , Tavakoli Javad , Zhao Jinchao , Tang Youhong 
Published: November 2016

ABSTRACTIn this study, electrospun nanofibers of poly (vinyl alcohol) (PVA) and styrene–butadiene–styrene triblock copolymer (SBS) were employed in conventional water‐swellable rubber (WSR) to design WSR composites with improved water swelling and mechanical properties. With the introduction of PVA nanofibers, considerable improvement in elasticity, strength, and water‐swelling behavior was observed. After immersion, PVA nanofibers dissolved within the composite to in situ form water channels to connect isolated super‐absorbent polymers (SAPs). Those water channels led to an increase in water uptake by the WSR composite. Furthermore, the secondary water‐swelling behaviors of the WSR composite showed a remarkable increase in swelling rate as well as in mechanical properties. The addition of SBS nanofibers had a marked impact on the mechanical properties of the WSR composite. Their roles became more pronounced after water immersion. The proposed enhancement mechanism is also discussed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44548.
Sulfated katira gum‐graft‐poly(N‐vinyl imidazole): A useful scavenger of mercury(II) ions
Authors: Kolya Haradhan , Jana Debprasad , Sasmal Dinabandhu , Jana Subinoy , Tripathy Tridib 
Published: November 2016

ABSTRACTKatira gum‐graft‐poly(N‐vinyl imidazole) was synthesized in a water medium with potassium perdisulfate as the free‐radical initiator at 70 ± 1 °C. The graft copolymer was sulfated by chlorosulfonic acid in the presence of pyridine and formamide. Various characterization techniques, including Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy, were used to characterize both the unsulfated and sulfated graft copolymers. The sulfated graft copolymer was used for the adsorption of Hg(II) ions from its aqueous solution. The operating variables affecting the Hg(II) adsorption, including the solution pH, amount of sulfated graft copolymer, contact time, and concentration of Hg(II), were investigated extensively. The sulfated graft copolymer was also used for competitive metal‐ion removal with Pb(II), Cd(II), Cu(II), and Zn(II). Metal complexation was studied with FTIR spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, and cyclic voltammetry analysis. The Hg(II) adsorption data of the sulfated graft copolymer were described well by the pseudo‐second‐order rate equation. The Langmuir adsorption isotherm provided the best correlation for the adsorption data. Various thermodynamic parameters for the adsorption were calculated. FTIR and UV–vis spectroscopy and cyclic voltammetry analysis before and after the adsorption of Hg(II) on the sulfated graft copolymer showed that columbic attraction was mainly responsible for the binding of the Hg(II) ions with the 
groups present in the sulfated graft copolymer. The sulfated graft copolymer showed a better adsorption performance than the graft copolymer itself under optimized conditions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44565.
Development of chitosan/Spirulina bio‐blend films and its biosorption potential for dyes
Authors: Silva J. M. , Farias B. S. , Gründmann D. D. R. , Cadaval T. R. S. , Moura J. M. , Dotto G. L. , Pinto L. A. A. 
Published: November 2016

ABSTRACTChitosan/Spirulina bio‐blends (CSBB) in films form were developed to be an alternative/renewable biosorbent, able to remove anionic and cationic dyes from aqueous solutions. CSBB potential as biosorbent was investigated for cationic dye Methylene Blue (MB), and anionic dyes Tartrazine Yellow (TY) and Reactive Black 5 (RB5). Chitosan and Spirulina samples were obtained and characterized, and CSBB films were prepared with different chitosan/Spirulina ratios. The CSBB films characteristics, as, mechanical properties, thermal profile, crystallinity, functional groups, morphology, and biosorption potential were strongly dependent of chitosan/Spirulina ratio. CSBB films preserved its mechanical structures at pH from 4.0 to 8.0. The biosorption capacities were 120, 110, and 100 mg g−1 for RB5, TY, and MB, respectively. The increase of chitosan amount favored the TY and RB5 biosorption; however, the increase of Spirulina amount favored the MB biosorption. Thus, the CSBB in film form is a renewable biosorbent suitable to remove anionic and cationic dyes from aqueous solutions. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44580.
Insights for Indigenous Policy from the Applied Behavioural Sciences
Authors: Biddle Nicholas 
Published: November 2016

AbstractPeople are neither completely rational, nor completely random in their decisions. Rather, they exhibit predictable biases that not only make it less likely that they will achieve their own stated desires, but also complicate the design and efficiency of public policy. These are some of the insights of the emerging applied behavioural sciences. With some notable exceptions, these insights have not always filtered through to policy formulation. Policy related to Aboriginal and Torres Strait Islander (Indigenous) Australians is one example of an area where insights from the applied behavioural sciences have the potential to improve the quality of policy decisions. A large amount of government funds is spent on Indigenous people reflecting a high degree of disadvantage. This paper provides new data and insights to understand the patterns and factors associated with decisions made by Indigenous people, thereby helping to improve the effectiveness of Indigenous policy.
Utilization of Red‐Light‐Emitting CdTe Nanoparticles for the Trace‐Level Detection of Harmful Herbicides in Adulterated Food and Agricultural Crops
Authors: Dey Nilanjan , Bhagat Deepa , Cherukaraveedu Durgadas , Bhattacharya Santanu 
Published: November 2016

AbstractRed‐light‐emitting water‐soluble semiconducting quantum dots (QDs) were synthesized by using a wide variety of commercially available thiol‐type capping agents. QDs with a negatively charged nanosurface showed excellent selectivity for paraquat (PQ) at pH 7.4 over other commonly encountered pesticides/herbicides, including diquat (DQ). The presence of a 4,4′‐bis‐pyridinium unit in PQ enabled it to initiate long‐range aggregation, thereby leading to the formation of nanostructures with excellent emission‐quenching behavior. Precoated quartz plates were developed as a low‐cost, portable sensor for the on‐site detection of PQ in both natural water and human urine. Estimation of the PQ concentration was performed in different commercial formulations and the detection of PQ contamination in adulterated dairy product was also achieved with excellent sensitivity. Finally, we screened more than 50 different food items, including vegetables, fruits, cereals, and fodders, to construct a generalized marker for any residual PQ in such specimens.
The interannual relationship between anomalous precipitation over southern China and the south eastern tropical Indian Ocean sea surface temperature anomalies during boreal summer
Authors: Huo Liwei , Jin Dachao 
Published: November 2016

AbstractThe relationship between anomalous precipitation in the Guangxi Autonomous Region and Guangdong Province (GG) and sea surface temperature anomalies (SSTA) over the south eastern tropical Indian Ocean (SETIO) during the boreal summer is investigated using observational data, reanalysis data and the atmospheric linear baroclinic model. It is demonstrated that the anomalous precipitation in GG (PGG) has a significantly negative correlation with the SSTA in SETIO. The warm SSTA in SETIO could induce below normal PGG in at least three ways. First, the warming over SETIO can cause two cyclonic circulations along the tropical Indian Ocean and easterlies from the tropical central Pacific though Matsuno‐Gill responses. The easterlies have the advantage of maintaining the anomalous negative vorticity in GG. Second, the water vapour diverges from SETIO and converges in GG. Finally, the anomalous ascent motion in SETIO is enhanced, which favours the strengthening of the anomalous local Hadley circulation over East Asia. The anomalous local Hadley circulation causes the anomalous descent motion in GG. All these anomalous circulations could favour below normal rainfall in GG and vice versa. This suggests the SSTA over SETIO could be a monitor of PGG.
A highly selective fluorescent chemosensor for Cu2+: synthesis and properties of a rhodamine B‐containing diarylethene
Authors: Xue Dandan , Zheng Chunhong , Qu Shengzu , Liao Guanming , Fan Congbin , Liu Gang , Pu Shouzhi 
Published: November 2016

AbstractA diarylethene bearing a triazole‐linked rhodamine B unit was synthesized. Its fluorescent emission was significantly enhanced in the presence of protons or Cu2+ due to transformation from the pirocyclic form to open‐ring form. The fluorescence was quenched sequentially upon irradiation with 297 nm light based on the intramolecular fluorescence resonance energy transfer mechanism. In an acetonitrile: water binary solvent (1: 1 v/v), the compound showed significant fluorescent enhancement for Cu2+ compared with a wide range of tested metal ions with a fast response and a limit of detection of 2.86 × 10−8 mol L−1. Using Cu2+ and UV light as the chemical inputs, and fluorescence intensity at 597 nm as the output, a logic gate was developed at the molecular level. Moreover, the compound can be used with a high accuracy to detect Cu2+ in a natural water sample.
Improved fermentative production of gamma‐aminobutyric acid via the putrescine route: Systems metabolic engineering for production from glucose, amino sugars, and xylose
Authors: Jorge João M. P. , Nguyen Anh Q. D. , Pérez‐García Fernando , Kind Stefanie , Wendisch Volker F. 
Published: November 2016

ABSTRACTGamma‐aminobutyric acid (GABA) is a non‐protein amino acid widespread in Nature. Among the various uses of GABA, its lactam form 2‐pyrrolidone can be chemically converted to the biodegradable plastic polyamide‐4. In metabolism, GABA can be synthesized either by decarboxylation of l‐glutamate or by a pathway that starts with the transamination of putrescine. Fermentative production of GABA from glucose by recombinant Corynebacterium glutamicum has been described via both routes. Putrescine‐based GABA production was characterized by accumulation of by‐products such as N‐acetyl‐putrescine. Their formation was abolished by deletion of the spermi(di)ne N‐acetyl‐transferase gene snaA. To improve provision of l‐glutamate as precursor 2‐oxoglutarate dehydrogenase activity was reduced by changing the translational start codon of the chromosomal gene for 2‐oxoglutarate dehydrogenase subunit E1o to the less preferred TTG and by maintaining the inhibitory protein OdhI in its inhibitory form by changing amino acid residue 15 from threonine to alanine. Putrescine‐based GABA production by the strains described here led to GABA titers up to 63.2 g L−1 in fed‐batch cultivation at maximum volumetric productivities up to 1.34 g L−1 h−1, the highest volumetric productivity for fermentative GABA production reported to date. Moreover, GABA production from the carbon sources xylose, glucosamine, and N‐acetyl‐glucosamine that do not have competing uses in the food or feed industries was established. Biotechnol. Bioeng. 2017;114: 862–873. © 2016 Wiley Periodicals, Inc.
Recent Advances in Boron‐Substituted 1,3‐Dienes Chemistry: Synthesis and Application
Authors: Pyziak Jadwiga , Walkowiak Jędrzej , Marciniec Bogdan 
Published: November 2016

AbstractIn the syntheses developed to access naturally occurring compounds, especially bioactive substances, boron‐functionalized dienes (also “linchpin” reagents) are used as key reagents. Structurally unique dienes are found in nature, and play important biological and chemical roles. Recently, linchpin moieties have been proved as useful substrates for a variety of highly functionalized chemical transformations. The products of these processes are potentially of some use for the syntheses of an important class of natural products showing a wide range of biological activities. This review describes progress in the synthesis of borylsubstituted buta‐1,3‐dienes as well as their application in organic chemistry.
Observation of Slow Relaxation and Single‐Molecule Toroidal Behavior in a Family of Butterfly‐Shaped Ln4 Complexes
Authors: Biswas Sourav , Das Sourav , Gupta Tulika , Singh Saurabh Kumar , Pissas Michael , Rajaraman Gopalan , Chandrasekhar Vadapalli 
Published: November 2016

AbstractA family of five isostructural butterfly complexes with a tetranuclear [Ln4] core of the general formula [Ln4(LH)2(μ2‐η1η1Piv)(η2‐Piv)(μ3‐OH)2]⋅x H2O⋅y MeOH⋅z CHCl3 (1: Ln=DyIII, x=2, y=2, z=0; 2: Ln=TbIII, x=0, y=0, z=6; 3: Ln=ErIII, x=2, y=2, z=0; 4: Ln=HoIII, x=2, y=2, z=0; 5: Ln=YbIII, x=2, y=2, z=0; LH4=6‐{[bis(2‐hydroxyethyl)amino]methyl}‐N′‐(2‐hydroxy‐3‐methoxybenzylidene)picolinohydrazide; PivH=pivalic acid) was isolated and characterized both structurally and magnetically. Complexes 1–5 were probed by direct and alternating current (dc and ac) magnetic susceptibility measurements and, except for 1, they did not display single‐molecule magnetism (SMM) behavior. The ac magnetic susceptibility measurements show frequency‐dependent out‐of‐phase signals with one relaxation process for complex 1 and the estimated effective energy barrier for the relaxation process was found to be 49 K. We have carried out extensive ab initio (CASSCF+RASSI‐SO+SINGLE_ANISO+POLY_ANISO) calculations on all the five complexes to gain deeper insights into the nature of magnetic anisotropy and the presence and absence of slow relaxation in these complexes. Our calculations yield three different exchange coupling for these Ln4 complexes and all the extracted J values are found to be weakly ferro/antiferromagentic in nature (J1=+2.35, J2=−0.58, and J3=−0.29 cm−1 for 1; J1=+0.45, J2=−0.68, and J3=−0.29 cm−1 for 2; J1=+0.03, J2=−0.98, and J3=−0.19 cm−1 for 3; J1=+4.15, J2=−0.23, and J3=−0.54 cm−1 for 4 and J1=+0.15, J2=−0.28, and J3=−1.18 cm−1 for 5). Our calculations reveal the presence of very large mixed toroidal moment in complex 1 and this is essentially due to the specific exchange topology present in this cluster. Our calculations also suggest presence of single‐molecule toroics (SMTs) in complex 2. For complexes 3–5 on the other hand, the transverse anisotropy was computed to be large, leading to the absence of slow relaxation of magnetization. As the magnetic field produced by SMTs decays faster than the normal spin moments, the concept of SMTs can be exploited to build qubits in which less interference and dense packing are possible. Our systematic study on these series of Ln4 complexes suggest how the ligand design can help to bring forth such SMT characteristics in lanthanide complexes.
Visualizing and Quantifying Interactions in the Excited State
Authors: Vannay Laurent , Brémond Eric , de Silva Piotr , Corminboeuf Clémence 
Published: November 2016

AbstractDetermining the location and nature of the electron pairs within a molecule provides an intuitive representation of electronic structures. Yet, most of the available theoretical representations are not suitable for describing excited state phenomena. The density overlap region indicator (DORI) scalar field, which depends only on the density and its derivatives, overcomes previous limitations, while keeping the intuitiveness of popular scalar fields. Here, its usefulness is demonstrated by pinpointing visual and numericalDORIsignatures for both intra‐ and intermolecular excited state situations.
Cooperative Activation of Isocyanates by Al–N‐Based Active Lewis Pairs and the Generation of a C5 Chain by Simultaneous Formation of Two C–C Bonds
Authors: Martinewski Katharina , Holtrichter‐Rößmann Thorsten , Rösener Christian , Hepp Alexander , Würthwein Ernst‐Ulrich , Uhl Werner 
Published: November 2016

AbstractThe active Al/N Lewis pair, (Me3C)2Al−C(SiMe3)=C(H)−N(CHMe‐CH2)2CH2 (2), reacted with isocyanates to afford a fascinating variety of products. One equivalent of Ph−N=C=O yielded by the release of H−C≡C−SiMe3 an urea‐type ligand which coordinated the Al atom in a chelating manner (4). Dipp‐N=C=O gave a similar product, but the bulky substituent hindered the approach of the N‐aryl group to Al. A situation similar to that of frustrated Lewis pairs resulted in the coordination of the alkyne to the Al and N atoms (6) by C−H bond activation. Dual insertion was observed upon treatment of 2 with two equivalents of isocyanates (8 to 11). The preferred formation of cyclic oligomers is prevented by the specific cooperative properties of the Lewis pair. A metal‐free dimeric isocyanate (13) was formed by hydrolysis. Replacement of the CMe3 groups in 2 by less bulky isobutyl groups (7) afforded the insertion of two isocyanate molecules into the Al–vinyl bonds without alkyne elimination. The resulting highly functionalised compound had a chain formed by two isocyanates and the organic backbone of the Lewis pair. Me3C−N=C=O and 2 afforded a unique compound (14) in which an isocyanate ligand connects two molecules of 2 by the release of dimethylpiperidine. The combination of a C1 building block and two C2 groups gave an unsaturated branched C5 moiety by the simultaneous formation of two C−C bonds. The molecular structure showed an interaction between an Al atom and a C−C π‐bond.
A Quantitative Study of the Effects of Guest Flexibility on Binding Inside a Coordination Cage Host
Authors: Taylor Christopher G. P. , Cullen William , Collier Olivia M. , Ward Michael D. 
Published: November 2016

AbstractWe have performed a systematic investigation of the effects of guest flexibility on their ability to bind in the cavity of a coordination cage host in water, using two sets of isomeric aliphatic ketones that differ only in the branching patterns of their alkyl chains. Apart from the expected increase in binding strength for C9 over C7 ketones associated with their greater hydrophobic surface area, within each isomeric set there is a clear inverse correlation between binding free energy and guest flexibility, associated with loss of conformational entropy. This can be parameterized by the number of rotatable C−C bonds in the guest, with each additional rotatable bond resulting in a penalty of around 2 kJ mol−1 in the binding free energy, in good agreement with values obtained from protein/ligand binding studies. We used the binding data for the new flexible guests to improve the scoring function that we had previously developed that allowed us to predict binding constants of relatively rigid guests in the cage cavity using the molecular docking programme GOLD (Genetic Optimisation of Ligand Docking). This improved scoring function resulted in a significant improvement in the ability of GOLD to predict binding constants for flexible guests, without any detriment to its ability to predict binding for more rigid guests.