bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational design of proteins stereochemically optimized in size, stability, and folding speed
Authors: Joshi Sadhna , Rana Soumendra , Wangikar Pramod , Durani Susheel 
Published: May 2006

AbstractArtificial proteins potentially barrier‐free in the folding kinetics are approached computationally under the guidance of protein‐folding theories. The smallest and fastest folding globular protein triple‐helix‐bundle (THB) is so modified as to minimize or eliminate its presumed barriers in folding speed. As the barriers may reside in the ordering of either secondary or tertiary structure, the elements of both secondary and tertiary structure in the protein are targeted for prenucleation with suitable stereochemically constrained amino acid residues. The required elements of topology and sequence for the THB are optimized independently; first the topology is optimized with simulated annealing in polypeptides of highly simplified alphabet; next, the sequence in side chains is optimized using the standard inverse design methods. The resultant three best‐adapted THBs, variable in topology and distinctive in sequences, are assessed by comparing them with a few benchmark proteins. The results of mainly molecular dynamics (MD) comparisons, undertaken in explicit water at different temperatures, show that the designed sequences are favorably placed against the chosen benchmarks as THB proteins potentially thermostable in the native folds. Folding simulation experiments with MD establish that the designed sequences are rapid in the folding of individual helices, but not in the evolution of tertiary structure; energetic cum topological frustrations remain but could be the artifacts of the starting conformations that were chosen in the THBs in the folding simulations. Overall, a practical high‐throughput approach for de novo protein design has been developed that may have fruitful application for any type of tertiary structure. © 2006 Wiley Periodicals, Inc. Biopolymers 83: 122–134, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Photoelectrochemical Kinetics of Eosin Y‐Sensitized Zinc Oxide Films Investigated by Scanning Electrochemical Microscopy
Authors: Shen Yan , Nonomura Kazuteru , Schlettwein Derck , Zhao Chuan , Wittstock Gunther 
Published: May 2006

AbstractEosin Y is used as a sensitizer for nanoporous zinc oxide films for prospective applications in photoelectrochemical solar cells. The kinetics of the reduction of the intermittently formed photo‐oxidized dye molecules by iodide ions in the electrolyte phase was investigated by using the feedback mode of scanning electrochemical microscopy (SECM). The bulk solution phase contained triiodide as electron transfer mediator, from which the ultramicroelectrode‐generated iodide ions acted as electron donors for photo‐oxidized Eosin Y molecules (D+ads) at the zinc oxide sample. Effective rate constants for the dye regeneration could be extracted from the SECM approach curves. The effective rate constants at different triiodide concentrations could be related to the rate constant for the reaction of the dissolved donor with photo‐oxidized Eosin Y bound to ZnO, as well as to the overall rate of the photosensitization process. For the reaction D+ads + 1.5 I−→Dads + 0.5 I3− a rate constant of kox = (1.4±0.8)×108 cm9/2 mol−3/2 s−1 was determined.
Competing Magnetic Interactions in Na10Co4O10, Studied by Neutron Diffraction
Authors: Stüßer Norbert , Sofin Mikhail , Bircher Roland , Güdel Hans‐Ulrich , Jansen Martin 
Published: May 2006

AbstractNa10Co4O10 was investigated by neutron powder diffraction at 230, 70, and 4 K. The crystal structure, determined previously by X‐ray diffraction on single crystals, was confirmed. Na10Co4O10 orders magnetically below 37 K. All observed magnetic reflections could be indexed by integers (hkl) with respect to the chemical unit cell and the magnetic propagation vector q=0. The refinement was performed in the Shubnikov space group C2/c and indicated a collinear antiferromagnetic spin structure. The determined spin arrangement is consistent with the magnetic intratetramer interactions suggested previously from the analysis of magnetic susceptibility data: the magnetic moments of the central CoIII ions of the Co4O10 tetramer lie parallel to each other and couple in an antiparallel fashion to the terminal CoII moments. The Rietveld analysis shows that the net moments of 0.64 μB per tetramer form ferromagnetic layers parallel to the ab plane. Adjacent layers are coupled antiferromagnetically along c. The spins are aligned in the ac plane along the line connecting adjacent CoII and CoIII ions of the tetramer. We have determined unusually low values for the ordered magnetic moments of 2.43(5) μB and 2.11(6) μB for CoIII and CoII, respectively. The occurrence of spontaneous magnetization below 37 K indicates a slight canting of 2.2° of the antiferromagnetic structure. A representation analysis shows that a weak ferromagnetic component along b is compatible with the determined antiferromagnetic structure.
Synthesis of Doubly Strappedmeso–meso‐Linked Porphyrin Arrays and Triply Linked Conjugated Porphyrin Tapes
Authors: Ikeda Toshiaki , Lintuluoto Juha M. , Aratani Naoki , Yoon Zin Seok , Kim Dongho , Osuka Atsuhiro 
Published: May 2006

Abstract1,10‐Dioxydecamethylene doubly strapped ZnII‐porphyrinS1was prepared and treated with AgPF6to givemeso–meso‐linked porphyrin oligomersSn(n= 2, 3, 4, 6, 8, and 12), which were converted to triply linked porphyrin tapesTSnbymeso,meso′‐dibromomeso–meso‐linked porphyrin arraysBSnandmeso,meso′‐diphenylmeso–meso‐linked porphyrin arraysPSn. The structures ofS1andS2have been determined by single‐crystal X‐ray diffraction analysis. Characteristically,Snexhibit sharp Q(0,0) absorption and fluorescence bands. Low energy Q‐band‐like absorption bands ofTSnare progressively red‐shifted with an increase in the number of porphyrins without saturation behavior of conjugation. The double straps suppress π–π stacking to some extent as seen from partial preservation of vibration structures in the Q‐band‐like bands ofTS4andTS6and improve the chemical stabilities of longer tapes such asTS8andTS12. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Syntheses, characterizations, and crystal structures of tri‐ and diorganotin (IV) derivatives with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole
Authors: Ma Chunlin , Li Jikun , Zhang Rufen 
Published: May 2006

AbstractA series of organotin(IV) complexes with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (HL) of the type R3 Sn(L) (R = Me 1; Bu 2; Ph 3; PhCH2 4) and R2Sn(L)2 (R = CH3 5; Ph 6; PhCH2 7; Bu 8) have been synthesized. All complexes 1–8 were characterized by elemental analysis, IR,1H, 13 C, and 119Sn NMR spectra. Among these, complexes 1, 3, 4, and 7 were also determined by X‐ray crystallography. The tin atoms of complexes 1, 3, and 4 are all penta‐coordinated and the geometries at tin atoms of complexes 3 and 4 are distorted trigonal–bipyramidal. Interestingly, complex 1 has formed a 1D polymeric chain through Sn and N intermolecular interactions. The tin atom of complex 7 is hexa‐coordinated and its geometry is distorted octahedral. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:353–364, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20215
Syntheses and spectroscopic investigation of some cyclophosphazanes: Analysis of pseudo‐triplet splitting
Authors: Gholivand Khodayar , Shariatinia Zahra , Tabasi Zahra Ahmadian , Tadjarodi Azadeh 
Published: May 2006

AbstractSome new phosphoramidates, 1–3, and the corresponding cyclophosphazanes, 4–6, with formula Cl2P(p‐NHC6H4CH3) 1, Cl2P(O)(p‐NHC6H4NO2) 2, (CH3)2NP(O)Cl(p‐NHC6H4CH3)3, [ClP(p‐NC6H4CH3)]2 4, [ClP(O)(p‐NC6H4NO2)]2 5, and [(CH3)2NP(O)(p‐NC6H4CH3)]2 6 were synthesized and characterized by 1H, 13C, 31P NMR, IR, mass spectroscopy, and elemental analysis. A pseudo‐triplet signal was observed in the 1H NMR spectrum of molecule 6 for the N(CH3)2 protons. The A6A′ 6X2 spin system was suggested for the pseudo‐triplet pattern of 3JPNCH coupling in this molecule. Ab initio calculations were performed at the HF and B3LYP levels of theory with 6‐311G** standard basis set on the geometry of compound 6. Also, the NMR chemical shift calculations were done to compare the computed results with the experimental ones. The calculated results are in good agreement with experimental data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:337–343, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20229
Electrochemical behavior of aluminium in acidic media
Authors: Jain T. , Chowdhary R. , Mathur S.P. 
Published: May 2006

AbstractThe inhibitive action of the acid extracts of seeds' leaves and bark from the Ficus virens plant towards hydrochloric and sulfuric acid corrosion of aluminium is tested using mass loss and thermometric techniques. It was found that the extract acts as a good corrosion inhibitor for aluminium corrosion in all concentration of hydrochloric and sulfuric acid solution. The ellagic acid has been used as a representative of the tannin species. The tannins are anodic inhibitors. The inhibition efficiency (IE) increases as the extract concentration is increased. The effect of temperature on the IE was studied. It was found that the presence of extract increases the activation energy of the corrosion reaction. Moreover, the heat of adsorption (Qads) was also calculated. It was found that the Ficus virens extract provides a good protection against pitting corrosion in chloride ion containing solution.
Active catheter tracking using parallel MRI and real‐time image reconstruction
Authors: Bock Michael , Müller Sven , Zuehlsdorff Sven , Speier Peter , Fink Christian , Hallscheidt Peter , Umathum Reiner , Semmler Wolfhard 
Published: May 2006

AbstractIn this work active MR catheter tracking with automatic slice alignment was combined with an autocalibrated parallel imaging technique. Using an optimized generalized autocalibrating partially parallel acquisitions (GRAPPA) algorithm with an acceleration factor of 2, we were able to reduce the acquisition time per image by 34%. To accelerate real‐time GRAPPA image reconstruction, the coil sensitivities were updated only after slice reorientation. For a 2D trueFISP acquisition (160 × 256 matrix, 80% phase matrix, half Fourier acquisition, TR = 3.7 ms, GRAPPA factor = 2) real‐time image reconstruction was achieved with up to six imaging coils. In a single animal experiment the method was used to steer a catheter from the vena cava through the beating heart into the pulmonary vasculature at an image update rate of about five images per second. Under all slice orientations, parallel image reconstruction was accomplished with only minor image artifacts, and the increased temporal resolution provided a sharp delineation of intracardial structures, such as the papillary muscle. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Krylov precise time‐step integration method
Authors: Fung T. C. , Chen Z. L. 
Published: May 2006

AbstractAn efficient precise time‐step integration (PTI) algorithm to solve large‐scale transient problems is presented in this paper. The Krylov subspace method and the Padé approximations are applied to modify the original PTI algorithm in order to improve the computational efficiency. Both the stability and accuracy characteristics of the resultant algorithms are investigated. The efficiency can be further improved by expanding the dimension to avoid the computation of the particular solutions. The present algorithm can also be extended to tackle nonlinear problems without difficulty. Two numerical examples are given to illustrate the highly accurate and efficient algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
Promoting autonomy of the client with persistent mental illness: A challenge for occupational therapists from The Netherlands, Germany and Belgium
Authors: Le Granse Mieke , Kinébanian Astrid , Josephsson Staffan 
Published: May 2006

AbstractThe aim of this study was to determine how occupational therapists from The Netherlands, Germany and Belgium promote the autonomy of clients with persistent mental illness. Sixty occupational therapists working in psychosocial mental health completed two semi‐structured questionnaires. Data were analysed by applying the constant comparative method. The results of the study show the importance of handling motivation in relation to personal autonomy and the different strategies occupational therapists use in promoting autonomy. In conclusion, enhancing clients' personal autonomy will empower and help them to discover meaningful occupations. More in‐depth information could have been obtained using an interview in combination with observations. Further research is needed to evaluate the effectiveness of strategies used by occupational therapists in promoting clients' autonomy. Copyright © 2006 John Wiley & Sons, Ltd.
Hyperbranched polycarbosiloxane with dendritic boron cores: Synthesis, characterization, and structure regulation
Authors: Kong Jie , Fan Xiaodong , Si Qingfa , Zhang Guobin , Wang Shengjie , Wang Xin 
Published: May 2006

AbstractThe synthesis, characterization, and structure regulation of hyperbranched polycarbosiloxane with dendritic boron cores were realized in this paper. First, dendritic boron core was synthesized via hydroboration with borane dimethylsulfide and bis(allyloxy)dimethylsilane. Then, the hyperbranched polycarbosiloxanes with dendritic boron cores were synthesized via hydrosilylation with AB2type monomer of bis(allyloxy)methylsilane and dendritic boron cores. The molecular structures of the dendritic boron core and resulting hyperbranched polymers were characterized by using Fourier transform infrared spectroscopy,1H nuclear magnetic resonance, and13C nuclear magnetic resonance spectroscopies. Size exclusion chromatography/multiangle laser light scattering analysis reveals that the structures of hyperbranched polycarbosiloxane can be regulated effectively by incorporation of functional dendritic boron cores. Compared with hyperbranched polycarbosiloxane of the same molecular weight level, the hyperbranched polycarbosiloxane with dendritic boron cores presents narrower molecular weight distribution as well as much smaller hydrodynamic radius and intrinsic viscosity. Thermalgravimetric analyzer analysis indicates that both the decomposition temperature and ceramic yields are increased as the results of the incorporation of dendritic boron cores into hyperbranched polycarbosiloxane. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3930–3941, 2006
Aligned single‐wall carbon nanotube polymer composites using an electric field
Authors: Park Cheol , Wilkinson John , Banda Sumanth , Ounaies Zoubeida , Wise Kristopher E. , Sauti Godfrey , Lillehei Peter T. , Harrison Joycelyn S. 
Published: May 2006

AbstractWhile high shear alignment has been shown to improve the mechanical properties of single‐wall carbon nanotube (SWNT)‐polymer composites, this method does not allow for control over the electrical and dielectric properties of the composite and often results in degradation of these properties. Here, we report a novel method to actively align SWNTs in a polymer matrix, which permits control over the degree of alignment of the SWNTs without the side effects of shear alignment. In this process, SWNTs were aligned via AC field‐induced dipolar interactions among the nanotubes in a liquid matrix followed by immobilization by photopolymerization under continued application of the electric field. Alignment of SWNTs was controlled as a function of magnitude, frequency, and application time of the applied electric field. The degree of SWNT alignment was assessed using optical microscopy and polarized Raman spectroscopy, and the morphology of the aligned nanocomposites was investigated by high‐resolution scanning electron microscopy. The structure of the field induced aligned SWNTs was intrinsically different from that of shear aligned SWNTs. In the present work, SWNTs are not only aligned along the field, but also migrate laterally to form thick, aligned SWNT percolative columns between the electrodes. The actively aligned SWNTs amplify the electrical and dielectric properties of the composite. All of these properties of the aligned nanocomposites exhibited anisotropic characteristics, which were controllable by tuning the applied field parameters. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1751–1762, 2006
Effect of annealing time on the self‐nucleation behavior of semicrystalline polymers
Authors: Lorenzo Arnaldo T. , Arnal María L. , Sánchez Johan J. , Müller Alejandro J. 
Published: May 2006

AbstractIt is widely known that when a polymer is heated just above its melting point and is kept at a given temperature (denoted Ts) for a short time, when it is cooled down its nucleation density increases and its peak crystallization temperature shifts to higher temperatures, as detected for instance by differential scanning calorimetry (DSC). The Ts temperature range where the described process occurs has been named Domain II self‐nucleation (SN) because the selected Ts temperatures are high enough to melt the polymer without causing detectable annealing of any remnant crystals by DSC. Experimental results obtained by DSC, polarized light optical microscopy (PLOM), and rheology indicate that these techniques are unable to detect any remaining crystal fragments in Domain II. Our kinetic results demonstrate that Domain II SN is a transient phenomenon that can even disappear if enough time at Ts is allowed. Results of the study of the time dependence of the SN effect indicates two possibilities: (a) if crystal fragments are present (even if undetected by the employed techniques) their final melting is a very slow process (in the order of hours); (b) if all crystallites have melted in Domain II, then it may be more plausible to reinterpret self‐nuclei as arising from “precursors” whose detail nature has not been the subject of this investigation but that can be regarded as either a residual segmental orientation in the melt (i.e., a melt memory effect) or a mesophase in a preordered state. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1738–1750, 2006
Si diffusion in epitaxial GaN
Authors: Jakiela Rafal , Barcz Adam , Dumiszewska Ewa , Jagoda Andrzej 
Published: May 2006

AbstractThe aim of this work is to determine diffusion coefficient of silicon in gallium nitride under different annealing conditions. Silicon was implanted into 3 µm thick GaN layer deposited on sapphire substrate with MOVPE (Metalorganic Vapour Phase Epitaxy) method. Implantation was performed at room temperature to a dose of 6×1015/cm2 at energy of 100 keV. The samples were annealed under 1 atm nitrogen pressure at 900–1200 °C with or without an AlN protective layer. The extent of diffusion of the implanted species was characterized using the SIMS (Secondary Ion Mass Spectrometry) technique. The resultant concentration profiles are characterized with two diffusion fronts: slow diffused Si atoms at high concentration and fast diffused Si atoms at low concentration. We ascribe the first mechanism as to originate from diffusion in the crystal bulk (substitutional migration), while the second one – from diffusion via grain boundaries/dislocations. Si diffusion coefficient in a crystal was found to be dependent on annealing conditions, in contrast to diffusion via grain boundary. Calculated diffusion coefficient parameters for annealing with and without AlN layer amount respectively to: DO = 6.5×10–11 cm2/s, Ea = 0.89 eV and DO = 9.1×10–8 cm2/s, Ea = 1.55 eV. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Twin concordances test for ascertained trichotomous traits data
Authors: Huang Jason Kunming , Tai John Jen 
Published: May 2006

AbstractIn human genetics, twin studies are widely underwent for investigation of the genetic influence on diseases. There are several measures that had been proposed to evaluate the similarity between two twins for dichotomous traits when the twins are sampled at random. These measures include the correlations, odds ratios, and casewise and pairwise concordances. When data are sampled through an ascertainment procedure, truncated data are formed. Under this circumstance, odds ratio cannot be defined and correlations cannot be correctly estimated. However, concordance measures for dichotomous traits can still be estimated using the likelihood method. On the other hand, though theoretically concordance measures can be extended to trichotomous traits, how to define them and to derive their estimators for ascertained trichotomous traits data have not been thoroughly discussed. In this study, we aim to address several relevant issues for ascertained trichotomous traits data. We define two new (casewise and pairwise) concordance measures for trichotomous traits and demonstrate how to apply a so‐called ‘self‐contained subsets method (SCSM)’ to estimation of twin concordances for ascertained data. We show that this method can obtain the same estimates as the likelihood method in an easier way and derive the asymptotic variances of the SCSM estimates under ascertainment. We establish the testing procedure for test of the equality of concordance measures between monozygotic twin pairs and dizygotic twin pairs, and illustrate the methods with a real data set and conduct Monte Carlo simulation to investigate its power performance. Copyright © 2006 John Wiley & Sons, Ltd.
Anaemia is an independent predictor of mortality in patients with left ventricular systolic dysfunction following acute myocardial infarction☆
Authors: Valeur Nana , Nielsen Olav Wendelboe , McMurray John J.V. , Torp‐Pedersen Christian , Køber Lars ,   TRACE Study Group
Published: May 2006

AbstractBackgroundIn patients with chronic heart failure (HF), mortality is inversely related to haemoglobin (hgb) concentration. We investigated the prognostic importance of anaemia in patients with acute myocardial infarction (AMI) and left ventricular systolic dysfunction (LVSD) with and without HF.Methods and resultsWe studied 1731 patients with AMI and left ventricular ejection fraction ≤35% from the TRAndolapril Cardiac Evaluation (TRACE) study. Mild anaemia (110 g/L ≤ hgb < 120 g/L in women and 120 g/L ≤ hgb < 130g/L in men) was present in 264 patients (15%), 114 (7%) had moderate (100 g/L ≤ hgb < 110 g/L in women and 110 g/L ≤ hgb < 120g/L in men) and 59 (3%) had severe (hgb < 100 g/L in women and < 110g/L in men) anaemia. According to the WHO criteria (hgb ≤120g/L in women and < 130g/L in men), 25% had anaemia. Anaemia was associated with increasing age, higher serum creatinine, lower body mass index, history of chronic HF, and worse NYHA class. In multivariable analyses including other prognostic factors only severe anaemia was associated with increased mortality, hazard ratio 1.59 (1.20–2.11). Anaemia was of prognostic importance in patients with HF, but not without HF. In HF patients the hazard ratios were 1.73 (1.26–2.36), 1.20 (0.93–1.56) and 1.05 (0.88–1.25) for severe, moderate and mild anaemia, respectively.ConclusionAnaemia is an independent predictor of mortality in patients with AMI and LVSD, but prognostic importance of anaemia is confined to the first year following AMI. The increased risk is driven by patients with severe anaemia and HF.