bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of novel europium β‐diketonate organic complexes for solid‐state lighting
Authors: Kalyani N. Thejo , Dhoble S. J. , Pode R. B. 
Published: June 2012

ABSTRACTVolatile Eu complexes, namely Eu(TTA)3Phen, Eu(x)Y(1‐x)(TTA)3 Phen; Eu(x)Tb(1‐x)(TTA)3Phen; Eu, europium; Y, yttrium; Tb, Terbium; TTA, thenoyltrifluoroacetone; and Phen, 1,10 phenanthroline were synthesized by maintaining stichiometric ratio. Various characterization techniques such as X‐ray diffraction (XRD), photoluminescence (PL) and thermo gravimetric analysis/differential thermal analysis (TGA/DTA) were carried out for the synthesized complexes. Diffractograms of all the synthesized complexes showed well‐resolved peaks, which revealed that pure and doped organic Eu3+ complexes were crystalline in nature. Of all the synthesized complexes, Eu0.5 Tb0.5(TTA)3Phen showed maximum peak intensity, while the angle of maximum peak intensity for all complexes was almost the same with slightly different d‐values. A prominent sharp red emission line was observed at 611 nm when excited with light at 370 nm. It was observed that the intensity of red emissions increased for doped europium complexes Eu(x)Y(1‐x)(TTA)3Phen and Eu(x)Tb(1‐x)(TTA)3 Phen, when compared with Eu complexes. Emission intensity increased in the following order: Eu(TTA)3Phen > Eu0.5 Tb0.5(TTA)3Phen > Eu0.4 Tb0.6(TTA)3Phen > Eu0.5Y0.5(TTA)3Phen > Eu0.4Y0.6(TTA)3Phen, proving their potential application in organic light‐emitting diodes (OLEDs). TGA showed that Eu complexes doped in Y3+ and Tb3+ have better thermal stability than pure Eu complex. DTA analysis showed that the melting temperature of Eu(TTA)3 Phen was lower than doped Eu complexes. These measurements infer that all complexes were highly stable and could be used as emissive materials for the fabrication of OLEDs. Copyright © 2012 John Wiley & Sons, Ltd.
Expression of Concern: Luminescence study of monodispersed ZnS nanoparticles
Authors: Murugadoss G. , Ramasamy V. 
Published: June 2012

ABSTRACTMonodispersed ZnS nanoparticles have been successfully synthesized by a chemical precipitation method in an air atmosphere using polyvinylpyrrolidone (PVP) and sodium hexametaphosphate (SHMP) as surfactants. The synthesized nanoparticles were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT‐IR), UV–Vis optical absorption and photoluminescence (PL) spectra. Prepared surfactants capped ZnS nanoparticles are highly homogeneous and well dispersed. Optical absorption spectra showed a strong blue shift from the uncapped particles due to the quantum confinement effect. The capped ZnS emission intensity is enhanced than more the uncapped particles. The size of the synthesized particles is around 4–6.5 nm range. Copyright © 2012 John Wiley & Sons, Ltd.
Molecular dynamics studies of the antimicrobial peptides piscidin 1 and its mutants with a DOPC lipid bilayer
Authors: Yuan Tianhu , Zhang Xin , Hu Zehan , Wang Fang , Lei Ming 
Published: June 2012

AbstractPiscidin 1 (Pis‐1) has a high broad‐spectrum activity against bacteria, fungi, and viruses but it also has a moderate hemolytic activities. To improve the antibacterial activity and to reduce toxicity, mutants Pis‐1AA (G8A/G13A double mutant) and Pis‐1PG (G8P mutant) have been designed based on the crystal structure of Pis‐1. Eighteen independent molecular dynamics (MD) simulations of Pis‐1 and its mutants with membranes are conducted in this article. Furthermore, 60 independent MD simulations of three peptides in water box have also been discussed for comparison. The results indicate that the unfolding process starts at the middle of the peptide. Pis‐1 disrupts easily in the region of Val10‐Lys14. Pis‐1PG has a flexible N‐terminal region, and the interaction between N‐terminal and C‐terminal is very weak. Pis‐1AA has the most stable helical structure. In addition, percentage of native contacts and hydrogen bonds analysis are also performed. Lipid‐peptide interaction analysis suggests that Pis‐1 and Pis‐1AA has a stronger interaction with the zwitterionic dioleoylphosphatidylcholine (DOPC) lipid bilayer than Pis‐1PG. When compared with the results of peptide with membrane, peptides are unstable and unfolding quickly in water solution. Our results are applicable in examining diversities on hemolytic, antibacterial, and selectivity of antimicrobial peptides. © 2012 Wiley Periodicals, Inc. Biopolymers 97:998–1009, 2012.
Borononucleotides as Substrates/Binders for Human NMP Kinases: Enzymatic and Spectroscopic Evaluation
Authors: El Amri Chahrazade , Martin Anthony R. , Vasseur Jean‐Jacques , Smietana Michael 
Published: June 2012

AbstractBorononucleotides are a family of natural nucleotide monophosphate analogues with a 5′‐boronic acid function. As BOP linkages are known to be unstable in solution, we evaluated the ability of borononucleotides to be recognized by nucleoside monophosphate kinases and eventually foil the phosphorylation process. In this context, and with the idea of probing the influence of their size, shape, and flexibility, a library of borononucleotides were synthetized starting from the borononucleotide analogue of thymidine, which was shown to behave as a slow substrate of human TMP kinase. This study thus constitutes a good starting point for the development of new monophosphate mimics as potential substrates or ligands for NMP kinases.
Phosphine–Imidazolyl Ligands for the Efficient Ruthenium‐Catalyzed Hydrogenation of Carboxylic Esters
Authors: Junge Kathrin , Wendt Bianca , Westerhaus Felix Alexander , Spannenberg Anke , Jiao Haijun , Beller Matthias 
Published: June 2012

AbstractThe synthesis of phosphine–imidazolyl ligands 1 and 2 in good yields is presented. In combination with [{Ru(benzene)Cl2}2], ligands 1 c and 1 e formed efficient catalyst systems for the selective hydrogenation of various carboxylic esters into their corresponding primary alcohols. Furthermore, the structures of four ruthenium complexes with ligands 1 b, 1 c, 1 d, and 1 e were determined by X‐ray crystallography, which showed the formation of different coordination modes depending on the ligand structure.
A Series of Trifacial Pd6 Molecular Barrels with Porphyrin Walls
Authors: Bar Arun Kumar , Mohapatra Sudip , Zangrando Ennio , Mukherjee Partha Sarathi 
Published: June 2012

AbstractThree new nanoscopic trigonal prisms, [(tmen)6Pd6(H2L)3](NO3)12 (1), [(Meen)6Pd6(H2L)3](NO3)12 (2), and [(2,2′‐bipy)6Pd6(H2L)3](NO3)12 (3), have been synthesized in excellent yields through single‐step metal–ligand‐coordination‐driven self‐assembly using 5,10,15,20‐tetrakis(3‐pyridyl)porphyrin (H2L) as a donor and cis‐blocked PdII 90° acceptors. These complexes were fully characterized by spectroscopic studies and single‐crystal X‐ray diffraction. All of these barrels quantitatively bind ZnII ions in the N4 pockets of the porphyrin walls at room temperature. Their corresponding zinc‐embedded complexes, [(tmen)6Pd6(ZnL)3](NO3)12 (1 a), [(Meen)6Pd6(ZnL)3](NO3)12 (2 a), and [(2,2′‐bipy)6Pd6(ZnL)3](NO3)12 (3 a), were synthesized under ambient conditions by the post‐synthetic binding of ZnII ions into the H2N4 pockets of the porphyrin walls of these complexes. These zinc‐embedded complexes were characterized by electronic absorption, fluorescence emission, 1H NMR spectroscopy, as well as elemental analysis. Complexes 1–3 exhibited considerable microporosity in their solid state. Complex 1 was an efficient adsorbent for nitrogen gas and EtOH, MeOH, and water vapors.
Water Makes the Difference: Rearrangement of Water Solvation Layer Triggers Non‐additivity of Functional Group Contributions in Protein–Ligand Binding
Authors: Biela Adam , Betz Michael , Heine Andreas , Klebe Gerhard 
Published: June 2012

AbstractThe binding of four congeneric peptide‐like thermolysin inhibitors has been studied by high‐resolution crystal structure analysis and isothermal titration calorimetry. The ligands differ only by a terminal carboxylate and/or methyl group. A surprising non‐additivity of functional group contributions for the carboxylate and/or methyl groups is detected. Adding the methyl first and then the carboxylate group results in a small Gibbs free energy increase and minor enthalpy/entropy partitioning for the first modification, whereas the second involves a strong affinity increase combined with large enthalpy/entropy changes. However, first adding the carboxylate and then the methyl group yields reverse effects: the acidic group attachment now causes minor effects, whereas the added methyl group provokes large changes. As all crystal structures show virtually identical binding modes, affinity changes are related to rearrangements of the first solvation layer next to the S2′ pocket. About 20–25 water molecules are visible next to the studied complexes. The added COO− groups perturb the local water network in both carboxylated complexes, and the attached methyl groups provide favorable interaction sites for water molecules. Apart from one example, a contiguously connected water network between protein and ligand functional groups is observed in all complexes. In the complex with the carboxylated ligand, which still lacks the terminal methyl group, the water network is unfavorably ruptured. This results in a surprising thermodynamic signature showing only a minor affinity increase upon COO− group attachment. Because the further added methyl group provides a favorable interaction site for water, the network can be reestablished, and a strong affinity increase with a large enthalpy/entropy signature is then detected.
Extracellular sheets and tunnels modulate glutamate diffusion in hippocampal neuropil
Authors: Kinney Justin P. , Spacek Josef , Bartol Thomas M. , Bajaj Chandrajit L. , Harris Kristen M. , Sejnowski Terrence J. 
Published: June 2012

AbstractAlthough the extracellular space in the neuropil of the brain is an important channel for volume communication between cells and has other important functions, its morphology on the micron scale has not been analyzed quantitatively owing to experimental limitations. We used manual and computational techniques to reconstruct the 3D geometry of 180 μm3 of rat CA1 hippocampal neuropil from serial electron microscopy and corrected for tissue shrinkage to reflect the in vivo state. The reconstruction revealed an interconnected network of 40–80 nm diameter tunnels, formed at the junction of three or more cellular processes, spanned by sheets between pairs of cell surfaces with 10–40 nm width. The tunnels tended to occur around synapses and axons, and the sheets were enriched around astrocytes. Monte Carlo simulations of diffusion within the reconstructed neuropil demonstrate that the rate of diffusion of neurotransmitter and other small molecules was slower in sheets than in tunnels. Thus, the non‐uniformity found in the extracellular space may have specialized functions for signaling (sheets) and volume transmission (tunnels). J. Comp. Neurol. 521:448–464, 2013. © 2012 Wiley Periodicals, Inc.
Magnetic‐Field‐Dependent 1H Relaxivity Behavior of Biotin/Avidin‐Based Magnetic Resonance Imaging Probes
Authors: Dhingra Verma Kirti , Mishra Anurag , Engelmann Jörn , Beyerlein Michael , Maier Martin E. , Logothetis Nikos K. 
Published: June 2012

AbstractOne major challenge in noninvasive mapping of various molecular targets is their inherently low in vivo concentration coupled with the insensitivity of imaging modalities, such as the widely used magnetic resonance imaging (MRI). Development of agents with high sensitivity and specificity is of paramount importance for structural and functional noninvasive imaging. The design, synthesis, and physiochemical characterization of two gadolinium‐based contrast agents (CAs) for MRI, the sensitivity of which was optimized by exploiting the well‐established biotin–avidin amplification strategies, are reported. The relaxivity of these agents showed a large increase if bound to avidin; specifically, the first compound showed an approximately 1000 % increase in transverse proton relaxivity (r2p), whereas the second compound had an approximately 250 % r2p increase. The increase in r2p was magnetic field independent in the range of 1.5–16.4 T whereas the longitudinal proton relaxivity (r1p) showed strong field dependence. The CAs were further characterized by measuring luminescence lifetimes and emission spectral changes upon addition of avidin to their Eu3+ analogues. The difference in relaxation rate behavior of both complexes was explained on the basis of hydration number modulation and the “global/internal motion concept”. The association constant of these CAs with avidin was found to be in the range of approximately 1015 M−1, which shows that the coupling of biotin to Gd‐DO3A did not affect its affinity for binding to avidin (DO3A=1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid).
Toward scale‐free like behavior under increasing cognitive load
Authors: Altamura Mario , Elvevåg Brita , Campi Gaetano , De Salvia Michela , Marasco Daniele , Ricci Alessandro , Bellomo Antonello 
Published: June 2012

AbstractTo understand how cognition and response selection processes might emerge from dynamic brain systems, we analyzed reaction times during the performance of both a working memory task and a choice reaction time task at different levels of “cognitive load.” Our findings suggest a continuous transition—tuned by load—from random behavior toward scale‐free like behavior as an expanding connectivity process in a network poised near a critical point. © 2012 Wiley Periodicals, Inc. Complexity, 2012
An Evaluation of the Impact of Introducing Compassion Focused Therapy to a Standard Treatment Programme for People with Eating Disorders
Authors: Gale Corinne , Gilbert Paul , Read Natalie , Goss Ken 
Published: June 2012

ObjectiveThis study explored the outcome of introducing Compassion Focused Therapy (CFT) into a standard treatment programme for people with eating disorders. In particular, the aim was to evaluate the principle that CFT can be used with people with eating disorders and improve eating disorder symptomatology.MethodRoutinely collected questionnaire data were used to assess cognitive and behavioural aspects of eating disorders and social functioning/well being (n = 99).ResultsThere were significant improvements on all questionnaire measures during the programme. An analysis by diagnosis found that people with bulimia nervosa improved significantly more than people with anorexia nervosa on most of the subscales. Also, in terms of clinical significance, 73% of those with bulimia nervosa were considered to have made clinically reliable and significant improvements at the end of treatment (compared with 21% of people with anorexia nervosa and 30% of people with atypical eating disorders).ConclusionThis study demonstrates the potential benefits of using CFT with people with eating disorders and highlights the need for further research on this new approach. Copyright © 2012 John Wiley & Sons, Ltd.Key Practitioner MessageCFT offers new ways to conceptualize and formulate some of the self‐critical and shame‐based difficulties associated with eating disorders.CFT offers a framework that can enable people with eating disorders to conceptualize their difficulties in different ways.CFT can be combined with standard therapies especially cognitive behavioural therapy.CFT can be especially useful in a group context where the relationships between members can become increasingly compassionate, validating, supportive and encouraging.
Implementation of cellular genetic algorithms on a CNN chip: Simulations and experimental results
Authors: Horváth András , Rásonyi Miklós 
Published: June 2012

SUMMARYOne of the most challenging recent problems in engineering is the development of proper topographic and parallel algorithms that can exploit the high performance of multi‐parallel architectures like cellular neural networks. We have developed, simulated and implemented a cellular version of the well‐known genetic algorithm which ideally suits these devices. The paper contains not only simulations, but an actual implementation and performance analysis on an existing architecture, the Xenon _ v3 digital cellular network, its emulator and its compiler. We support our conclusions by testing the algorithm on the traveling salesman problem. Copyright © 2012 John Wiley & Sons, Ltd.
Physical unclonable functions based on crossbar arrays for cryptographic applications
Authors: Lugli Paolo , Mahmoud Ahmed , Csaba György , Algasinger Michael , Stutzmann Martin , Rührmair Ulrich 
Published: June 2012

SUMMARYDue to their attractive, regular structure and their simple implementation, crossbar arrays have become one major emerging research area in the fields of nano‐devices and electronic circuits. This paper discusses novel applications of crossbars as various types of so‐called physical unclonable functions (PUFs) in the field of physical cryptography. The latter is a recent branch of cryptography and security that exploits the inherent, small‐scale randomness and disorder in physical structures. PUFs are the currently dominant primitive within this new field.In order to establish the applicability of crossbar structures as PUFs, two crossbars with rectifying junctions are investigated on the basis of real measurement data. In addition, the scalability of these crossbars with respect to their power dissipation and noise margin is evaluated in simulations. The types of PUFs as which crossbars can serve include weak PUFs and super high information content PUFs. We also discuss whether crossbar‐based PUFs allow the erasure and/or rewriting of response information on a single challenge‐response‐pair level, i.e. without affecting other PUF responses. Copyright © 2012 John Wiley & Sons, Ltd.
Resource allocation for OFDM relay systems with statistical QoS guarantees
Authors: Huang Gaofei , Zhang Guangchi , Zhang Ping , Tang Dong , Qin Jiayin 
Published: June 2012

SUMMARYBy integrating the concept of effective capacity, we propose the resource allocation schemes for subcarrier‐pair based OFDM decode‐and‐forward and amplify‐and‐forward relay systems for quality‐of‐service (QoS) guarantees. The objective is to maximize the system throughput subject to a given statistical delay QoS constraint. First, we pair the subcarriers over the source‐relay channel and the relay‐destination channel by the descending order of the subcarriers' channel gains. Second, by making use of the derived equivalent end‐to‐end channel gains of the subcarrier pairs, we apply joint water‐filling power allocation over the subcarrier pairs and then partition the power of the subcarrier pairs between the source and the relay. We prove that as the equivalent end‐to‐end channel gains of the subcarrier pairs are given, the combination of sorted subcarrier pairing and joint water‐filling power allocation is jointly optimal to maximize the effective capacity. The simulation results show that our proposed schemes achieve the highest effective capacity for OFDM decode‐and‐forward and amplify‐and‐forward relay systems as compared with other existing schemes. The results also verify that our proposed schemes can efficiently provide different levels of delay QoS guarantees, even if under the stringent delay QoS constraints. Copyright © 2012 John Wiley & Sons, Ltd.
Prenatal and postnatal animal models of immune activation: Relevance to a range of neurodevelopmental disorders
Authors: Harvey Louise , Boksa Patricia 
Published: June 2012

AbstractEpidemiological evidence has established links between immune activation during the prenatal or early postnatal period and increased risk of developing a range of neurodevelopment disorders in later life. Animal models have been used to great effect to explore the ramifications of immune activation during gestation and neonatal life. A range of behavioral, neurochemical, molecular, and structural outcome measures associated with schizophrenia, autism, cerebral palsy, and epilepsy have been assessed in models of prenatal and postnatal immune activation. However, the epidemiology‐driven disease‐first approach taken by some studies can be limiting and, despite the wealth of data, there is a lack of consensus in the literature as to the specific dose, timing, and nature of the immunogen that results in replicable and reproducible changes related to a single disease phenotype. In this review, we highlight a number of similarities and differences in models of prenatal and postnatal immune activation currently being used to investigate the origins of schizophrenia, autism, cerebral palsy, epilepsy, and Parkinson's disease. However, we describe a lack of synthesis not only between but also within disease‐specific models. Our inability to compare the equivalency dose of immunogen used is identified as a significant yet easily remedied problem. We ask whether early life exposure to infection should be described as a disease‐specific or general vulnerability factor for neurodevelopmental disorders and discuss the implications that either classification has on the design, strengths and limitations offuture experiments. © 2012 Wiley Periodicals, Inc. Develop Neurobiol, 2012
Uranyl(VI) Complexation by Sulfonate Ligands: A Relativistic Density Functional and Time‐Resolved Laser‐Induced Fluorescence Spectroscopy Study
Authors: Kremleva Alena , Zhang Yun , Shor Aleksey M. , Krüger Sven , Joseph Claudia , Raditzky Bianca , Schmeide Katja , Sachs Susanne , Bernhard Gert , Rösch Notker 
Published: June 2012

AbstractTo study the role of sulfonate functional groups of humic substances in uranyl(VI) complexation, all‐electron density functional calculations and time‐resolved laser‐induced fluorescence spectroscopy (TRLFS) were applied using small sulfonate ligands as models. A thiolate ligand was explored for comparison. As in an earlier experiment, 4‐hydroxybenzenesulfonic acid (HBSA) and benzenesulfonic acid (BSA) were examined and compared to methylsulfonic acid (MSA). Structural parameters as well as energetic aspects of uranyl complexes by BSA and HBSA ligands were determined to be rather similar, in contrast to earlier experimental findings. The present TRLFS measurements show complexation of uranyl by both ligands, which is in agreement with the computational results. Overall, the combined computational and experimental results also indicate that sulfonate groups play only a minor role in uranyl complexation of humic substances because of the rather low stability constants.
Effect of the Nitrogen Substituent on the Reactions of Alane towards Imino‐ and Aminophenols: Generation of a Dinuclear Aluminoxane
Authors: Martínez Gema , Cuenca Tomás , Mosquera Marta E. G. 
Published: June 2012

AbstractAlH3·NEtMe2 reacts with salicylaldimines 3,5‐tBu2–2‐(OH)C6H2CH=NR [R = C6F5 (1a), 2,6‐Me2C6H3 (1b); 0.5 equiv.] to give the bisphenoxido‐amido‐imino compounds [Al{3,5‐tBu2–2‐(O)C6H2CH=NR}{3,5‐tBu2–2‐(O)C6H2CH2–NR}] [R = C6F5 (4a), 2,6‐Me2C6H3 (4b)]. When the substituent on the nitrogen is 2,6‐Me2C6H3, it is possible to isolate the bis(phenoxido‐imino) hydride [AlH{3,5‐tBu2–2‐(O)C6H2CH=N–2,6‐Me2C6H3}2] (3) if the reaction is performed at low temperature. Compound 4a is converted in wet toluene at room temperature readily and quantitatively into the aluminoxane [(Al{3,5‐tBu2–2‐(O)C6H2CH=NC6F5}{3,5‐tBu2–2‐(O)C6H2CH2–NHC6F5})2O] (5). The mononuclear bis(phenoxido‐amino) hydrides [AlH{3,5‐tBu2–2‐(O)C6H2CH2–NHR}2] [R = 2,6‐Me2C6H3 (6b), tBu (6c)] are obtained by treatment of AlH3·NEtMe2 with aminophenols 3,5‐tBu2–2‐(OH)C6H2CH2–NHR [R = 2,6‐Me2C6H3 (2b), tBu (2c); 0.5 equiv.] in toluene at –78 °C. Compound 6b evolves into [Al{3,5‐tBu2–2‐(O)C6H2CH2–NH–2,6‐Me2C6H3}{3,5‐tBu2–2‐(O)C6H2CH2–N–2,6‐Me2C6H3}] (7), which can also be generated by the direct reaction of 2b with AlH3·NEtMe2 (0.5 equiv.) at room temperature. The molecular structures of 4b and 5 have been determined by X‐ray diffraction analysis.