bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biodegradability, antibacterial properties, and ultraviolet protection of polyvinyl alcohol‐natural polyphenol blends
Authors: Xu Xiang‐Ju , Huang Shao‐Ming , Zhang Li‐Hua 
Published: November 2008

AbstractPolymer films of tea polyphenol (TP)/polyvinyl alcohol (PVA) were prepared by a solution casting. The films were studies for intermolecular interactions by Fourier transform infrared spectroscopy, the shifts in the major signals of IR for OH and CO absorption, and with varied intensities in the Fourier transform infrared spectroscopy spectra indicated intermolecular hydrogen bonded interaction between PVA and TP. The biodegradability of the PVA/TP blends is measured by soil burial test, the percentage weight loss of the PVA/TP blends increased with increasing TP content. And the antibacterial activity of PVA/TP blends was determined by shake flask test and three kinds of bacteria used were as follows: Staphylcoccus aures, Escherichia coli, and Proteus valgaris. The blends exhibit strong antibacterial activity against the three kinds of bacteria. According to the Australia/New Zealand standard, AS/NZS 4399:1996, the ultraviolet protective properties of the PVA/TP blends were evaluated and the result shows that the capacity of the ultraviolet protection for blends was extremely increased by adding TP to PVA. And all blends reach the highest level (50+) of the standard. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Uniformity of silicon microcrystallinity in large area RF capacitive reactors
Authors: Strahm Benjamin , Hollenstein Christoph , Howling Alan A. 
Published: November 2008

AbstractIn this work, a controlled, nonuniform RF power distribution is produced across a large area PECVD reactor. The effect of the RF power distribution on the crystallinity of silicon thin films deposited from silane‐hydrogen discharges is studied. Results show that, even with a strongly nonuniform RF distribution (70%), uniform crystallinity can still be achieved for films deposited at the limit between amorphous and microcrystalline silicon provided that the input silane concentration is sufficiently low (nominal concentration lower than ≈︂1˙2%). This work shows that to deposit silicon with a uniform microcrystallinity over large area using high silane concentration, the reactor design must guarantee a highly uniform power distribution. Copyright © 2008 John Wiley & Sons, Ltd.
Redox reactions of copper(II) upon electrospray ionization in the presence of acridine ligands with an amide side chain
Authors: Tintaru Aura , Charles Laurence , Milko Petr , Roithová Jana , Schröder Detlef 
Published: November 2008

AbstractThe complexation of copper(II) to acridine derivatives has been studied by means of electrospray ionization (ESI) mass spectrometry. Under soft conditions of ionization, the ESI mass spectra of methanolic solutions of copper(II) chloride and the acridine ligands show abundant signals of the mononuclear complexes formed from the metal and ligand. Depending on the position of the N‐benzoylamino substituent in the acridinic heterocycle, however, the copper atom involved in the complexation process adopts different oxidation states in the resulting cations. Hence, the metal is reduced to copper(I) in the monocationic complex with the compound substituted in position 2, whereas it keeps its divalent state in the monocation formed with the compound substituted in position 4. As a consequence, the regioisomers lead to monocations with different masses in the ESI spectra. In order to understand this unusual behavior of two isomeric compounds, additional experiments have been performed with quinoline as a model. Copyright © 2008 John Wiley & Sons, Ltd.
Investigating the binding of β‐1,4‐galactan to Bacillus licheniformis β‐1,4‐galactanase by crystallography and computational modeling
Authors: Le Nours Jérôme , De Maria Leonardo , Welner Ditte , Jørgensen Christel T. , Christensen Lars L. H. , Borchert Torben V. , Larsen Sine , Lo Leggio Leila 
Published: November 2008

AbstractMicrobial β‐1,4‐galactanases are glycoside hydrolases belonging to family 53, which degrade galactan and arabinogalactan side chains in the hairy regions of pectin, a major plant cell wall component. They belong to the larger clan GH‐A of glycoside hydrolases, which cover many different poly‐ and oligosaccharidase specificities. Crystallographic complexes of Bacillus licheniformis β‐1,4‐galactanase and its inactive nucleophile mutant have been obtained with methyl‐β(1→4)‐galactotetraoside, providing, for the first time, information on substrate binding to the aglycone side of the β‐1,4‐galactanase substrate binding groove. Using the experimentally determined subsites as a starting point, a β(1→4)‐galactononaose was built into the structure and subjected to molecular dynamics simulations giving further insight into the residues involved in the binding of the polysaccharide from subsite −4 to +5. In particular, this analysis newly identified a conserved β‐turn, which contributes to subsites −2 to +3. This β‐turn is unique to family 53 β‐1,4‐galactanases among all clan GH‐A families that have been structurally characterized and thus might be a structural signature for endo‐β‐1,4‐galactanase specificity. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Intrinsic structural disorder of mouse proNGF
Authors: Paoletti Francesca , Covaceuszach Sonia , Konarev Peter V. , Gonfloni Stefania , Malerba Francesca , Schwarz Elisabeth , Svergun Dmitri I. , Cattaneo Antonino , Lamba Doriano 
Published: November 2008

AbstractThe unprocessed precursor of the Nerve Growth Factor (NGF), proNGF, has additional functions, besides its initially described role as a chaperone for NGF folding. The precursor protein endows apoptotic and/or neurotrophic properties, in contrast to the mature part. The structural and molecular basis for such distinct activities are presently unknown. Aiming to gain insights into the specific molecular interactions that govern rm‐proNGF biological activities versus those of its mature counterpart, a structural study by synchrotron small angle X‐ray scattering (SAXS) in solution was carried out. The different binding properties of the two proteins were investigated by surface plasmon resonance (SPR) using, as structural probes, a panel of anti‐NGF antibodies and the soluble forms of TrkA and p75NTR receptors. SAXS measurements revealed the rm‐proNGF to be dimeric and anisometric, with the propeptide domain being intrinsically unstructured. Ab initio reconstructions assuming twofold symmetry generated two types of structural models, a globular “crab‐like” and an elongated shape that resulted in equally good fits of the scattering data. A novel method accounting for possible coexistence of different conformations contributing to the experimental scattering pattern, with no symmetry constraints, suggests the “crab‐like” to be a more likely proNGF conformation. To exploit the potential of chemical stabilizers affecting the existing conformational protein populations, SAXS data were also collected in the presence of ammonium sulphate. An increase of the proNGF compactness was observed. SPR data pinpoints that the propeptide of proNGF may act as an intrinsically unstructured protein domain, characterized by a molecular promiscuity in the interaction/binding to multiple partners (TrkA and p75NTR receptors and a panel of neutralizing anti‐NGF antibodies) depending on the physiological conditions of the cell. These data provide a first insight into the structural basis for the selectivity of mouse short proNGF, versus NGF, towards its binding partners. Proteins 2009. © 2008 Wiley‐Liss, Inc.
All‐atom chain‐building by optimizing MODELLER energy function using conformational space annealing
Authors: Joo Keehyoung , Lee Jinwoo , Seo Joo‐Hyun , Lee Kyoungrim , Kim Byung‐Gee , Lee Jooyoung 
Published: November 2008

AbstractWe have investigated the effect of rigorous optimization of the MODELLER energy function for possible improvement in protein all‐atom chain‐building. For this we applied the global optimization method called conformational space annealing (CSA) to the standard MODELLER procedure to achieve better energy optimization than what MODELLER provides. The method, which we call MODELLERCSA, is tested on two benchmark sets. The first is the 298 proteins taken from the HOMSTRAD multiple alignment set. By simply optimizing the MODELLER energy function, we observe significant improvement in side‐chain modeling, where MODELLERCSA provides about 10.7% (14.5%) improvement for χ1 (χ1 + χ2) accuracy compared to the standard MODELLER modeling. The improvement of backbone accuracy by MODELLERCSA is shown to be less prominent, and a similar improvement can be achieved by simply generating many standard MODELLER models and selecting lowest energy models. However, the level of side‐chain modeling accuracy by MODELLERCSA could not be matched either by extensive MODELLER strategies, side‐chain remodeling by SCWRL3, or copying unmutated rotamers. The identical procedure was successfully applied to 100 CASP7 template base modeling domains during the prediction season in a blind fashion, and the results are included here for comparison. From this study, we observe a good correlation between the MODELLER energy and the side‐chain accuracy. Our findings indicate that, when a good alignment between a target protein and its templates is provided, thorough optimization of the MODELLER energy function leads to accurate all‐atom models. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Mechanical unfolding pathway and origin of mechanical stability of proteins of ubiquitin family: An investigation by steered molecular dynamics simulation
Authors: Das Atanu , Mukhopadhyay Chaitali 
Published: November 2008

AbstractLike the muscle protein Titin, proteins of the ubiquitin family exhibit a parallel strand arrangement, but otherwise having a distinctly different fold and not involved in an obvious load‐bearing function, exhibit high resistance to mechanical unfolding. We have applied all‐atom molecular dynamics simulation technique in implicit solvent to present a deep insight into the force‐induced unfolding pathway of three proteins—ubiquitin, NEDD8, and SUMO‐2—all having almost similar structural features. Two intermediates evolve in the unfolding pathway of each of the three proteins. The first intermediate, which has already been identified in case of ubiquitin by earlier simulation results, is similar for ubiquitin and NEDD8, but different in SUMO‐2. We have found a new intermediate with β3–β4 hairpin and some residual α‐helical character; and this intermediate is common for all the three proteins. Thus, proteins of the ubiquitin family pass through a well‐defined conformation in their force‐induced unfolding pathway. Reason behind the higher mechanical stability of the proteins with parallel strand structures like Titin has also been identified. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Domain motions of hyaluronan lyase underlying processive hyaluronan translocation
Authors: Joshi Harshad V. , Jedrzejas Mark J. , de Groot Bert L. 
Published: November 2008

AbstractHyaluronan lyase (Hyal) is a surface enzyme occurring in many bacterial organisms including members of Streptococcus species. Streptococcal Hyal primarily degrades hyaluronan‐substrate (HA) of the extracellular matrix. This degradation appears to facilitate the spread of this bacterium throughout host tissues. Unlike purely endolytic degradation of its other substrates, unsulfated chondroitin or some chondroitin sulfates, the degradation of HA by Hyal proceeds by processive exolytic cleavage of one disaccharide at a time following an initial endolytic cut. Molecular dynamics (MD) studies of Hyal from Streptococcus pneumoniae are presented that address the enzyme's molecular mechanism of action and the role of domain motions for processive functionality. The analysis of extensive sub‐microsecond MD simulations of this enzyme action on HA‐substrates of different lengths and the connection between the domain dynamics of Hyal and the translocation of the HA‐substrate reveals that opening/closing and twisting domain motions of the Hyal are intimately linked to processive HA degradation. Enforced simulations confirmed this finding as the domain motions in SpnHyal were found to be induced by enforced substrate translocation. These results establish the dynamic interplay between Hyal flexibility and substrate translocation and provide insight into the processive mechanism of Hyal. Proteins 2009. © 2008 Wiley‐Liss, Inc.
A comparison of polycrystalline elastic properties computed by analytic homogenization schemes and FEM
Authors: Counts W. A. , Friák M. , Battaile C. C. , Raabe D. , Neugebauer J. 
Published: November 2008

AbstractBody‐center‐cubic (BCC) magnesium–lithium alloys are a promising light‐weight structural material. As a first step in a theoretically guided materials design strategy single crystal elastic coefficients for BCC magnesium‐lithium alloys with different compositions were computed using ab initio methods. These single crystal elastic coefficients were then used to predict the corresponding polycrystalline elastic properties using various analytic homogenization techniques (Voigt, Reuss, and a self‐consistent approach) as well as the finite element method. As expected, the Voigt and Reuss bounds form the upper and lower bounds on the polycrystalline elastic properties, which the predicted values of the self‐consistent approach and finite element approaches fall in between. Additionally, the difference between the polycrystalline elastic properties derived from the self‐consistent approach and the finite element method is small illustrating the power and value of the self‐consistent approach for non‐textured materials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fault‐tolerant procedures for redundant computer systems
Authors: Samet Refik 
Published: November 2008

AbstractReal‐time computer systems deployed in life‐critical control applications must be designed to meet stringent reliability specifications. The minimum acceptable degree of reliability for systems of this type is ‘7 nines’, which is not generally achieved. This paper aims at contributing to the achievement of that degree of reliability. To this end, this paper proposes a classification scheme of the fault‐tolerant procedures for redundant computer systems (RCSs). The proposed classification scheme is developed on the basis of the number of counteracted fault types. Table I is created to relate the characteristics of the RCSs to the characteristics of the fault‐tolerant procedures. A selection algorithm is proposed, which allows designers to select the optimal type of fault‐tolerant procedures according to the system characteristics and capabilities. The fault‐tolerant procedure, which is selected by this algorithm, provides the required degree of reliability for a given RCS. According to the proposed graphical model only a part of the fault‐tolerant procedure is executed depending on the absence or presence (type and sort) of faults. The proposed methods allow designers to counteract Byzantine and non‐Byzantine fault types during degradation of RCSs fromNto 3, and only the non‐Byzantine fault type during degradation from 3 to 1 with optimal checkpoint time period. Copyright © 2008 John Wiley & Sons, Ltd.
Prediction variance and G‐criterion location for split‐plot designs
Authors: Wesley Wayne R. , Simpson James R. , Parker Peter A. , Pignatiello Joseph J. 
Published: November 2008

AbstractPrediction variance properties for completely randomized designs (CRD) are fairly well covered in the response surface literature for both spherical and cuboidal designs. This paper evaluates the impact of changes in the variance ratio on the prediction properties of second‐order split‐plot designs (SPD). It is shown that the variance ratio not only influences the value of the G‐criterion but also its location, in contrast with the G‐criterion tendencies in CRD. An analytical method, rather than a heuristic optimization algorithm, is used to compute the prediction variance properties, which include the maximum, minimum and integrated variances for second‐order SPD. The analytical equations are functions of the design parameters, radius and variance ratio. As a result, the exact values for these quantities are reported along with the location of the maximum prediction variance used in the G‐criterion. The two design spaces of the whole plot and the subplot are studied and as a result, relative efficiency values for these distinct spaces are suggested. Copyright © 2008 John Wiley & Sons, Ltd.
An improved run‐to‐run process control scheme for categorical observations with misclassification errors
Authors: Shang Yanfen , Wang Kaibo , Tsung Fugee 
Published: November 2008

AbstractWhen product quality characteristics are evaluated and assigned to exclusive categories, measurement errors (misclassification of products) always exist unless a perfect measurement system is used to identify the categories. In run‐to‐run (R2R) process control, a categorical controller has been developed for process adjustments with categorical variables. However, if process outputs are misclassified, an adjustment bias will be introduced by the controller. In this study, an improved categorical R2R controller that utilizes the misclassification probabilities to decrease process deviation is proposed. Simulation results show that the proposed controller exhibits better performance when misclassification exists. Copyright © 2008 John Wiley & Sons, Ltd.
Bayesian belief networks for system fault diagnostics
Authors: Lampis M. , Andrews J. D. 
Published: November 2008

AbstractFault diagnostic methods aim to recognize when faults exist on a system and to identify the failures that have caused the fault. The symptoms of the fault are obtained from readings from sensors located on the system. When the observed readings do not match those expected then a fault can exist. Using the detailed information provided by the sensors, a list of the failures (singly or in combinations) that could cause the symptoms can be deduced. In the last two decades, fault diagnosis has received growing attention due to the complexity of modern systems and the consequent need for more sophisticated techniques to identify the failures when they occur. Detecting the causes of a fault quickly and efficiently means reducing the costs associated with the system unavailability and, in certain cases, avoiding the risks of unsafe operating conditions. Bayesian belief networks (BBNs) are probabilistic models that were developed in artificial intelligence applications but are now applied in many fields. They are ideal for modelling the causal relations between faults and symptoms used in the detection process. The probabilities of events within the BBN can be updated following observations (evidence) about the system state. In this paper we investigate how BBNs can be applied to diagnose faults on a system. Initially Fault trees (FTs) are constructed to indicate how the component failures can combine to cause unexpected deviations in the variables monitored by the sensors. Converting FTs into BNs enables the creation of a model that represents the system with a single network, which is constituted by sub‐networks. The posterior probabilities of the components' failures give a measure of those components that have caused the symptoms observed. The method gives a procedure that can be generalized for any system where the causality structure can be developed relating the system component states to the sensor readings. The technique is demonstrated with a simple example system. Copyright © 2008 John Wiley & Sons, Ltd.
The general balance metric for mixed‐level fractional factorial designs
Authors: Guo Yong , Simpson James R. , Pignatiello Joseph J. 
Published: November 2008

AbstractMixed‐level designs are employed when factors with different numbers of levels are involved. Practitioners use mixed‐level fractional factorial designs as the total number of runs of the full factorial increases rapidly as the number of factors and/or the number of factor levels increases. One important decision is to determine which fractional designs should be chosen. A new criterion, the general balance metric (GBM), is proposed to evaluate and compare mixed‐level fractional factorial designs. The GBM measures the degree of balance for both main effects and interaction effects. This criterion is tied to, and dominates orthogonality criteria as well as traditional minimum aberration criteria. Furthermore, the proposal is easy to use and has practical interpretations. As part of the GBM, the concept of resolution is generalized and the confounding structure of mixed‐level fractional factorial designs is also revealed. Moreover, the metric can also be used for the purpose of design augmentation. Examples are provided to compare this approach with existing criteria. Copyright © 2008 John Wiley & Sons, Ltd.
Theoretical study on the spectroscopic properties and electronic structures of heteroleptic phosphorescent Ir(III) complexes
Authors: Zhang Min , Li Ze‐Sheng , Li Yan , Liu Jia , Sun Jia‐Zhong 
Published: November 2008

AbstractThe geometries, spectroscopic and electronic structures properties of a series of heteroleptic phosphorescent Ir(III) complexes including N981, N982, N983, N984 have been characterized by density functional theory calculations. The excited‐state properties of the Ir(III) complexes have been characterized by CIS method. The ground‐ and excited‐state geometries were optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ levels, respectively. By using the time‐dependent density functional theory method, the absorption and phosphorescence spectra were calculated based on the optimized ground‐ and excited‐state geometries, respectively. The results show that the absorption and emission data agree well with the corresponding experimental results. The calculated results also revealed that the nature of the substituent at the 4‐position of the pyridyl moiety can influence the distributions of HOMO and LUMO and their energies. In addition, the charge transport quality has been estimated approximately by the calculated reorganization energy (λ). Our result also indicates that the positions of the substitute groups not only change the transition characters but also affect the charge transfer rate and balance, and complex N982 is a very good charge transfer material for green OLEDs. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Structural classification of acyl‐substituted Quillaja saponins by electrospray ionisation ion trap multiple‐stage mass spectrometry in combination with multivariate analysis
Authors: Bankefors Johan , Nord Lars I. , Kenne Lennart 
Published: November 2008

AbstractThirty‐eight saponins in two chromatographic fractions (QH‐B and QH‐C) from Quillaja saponaria Molina have been separated by a two‐step high‐performance liquid chromatography (HPLC) procedure and investigated by electrospray ionisation ion trap multiple‐stage mass spectrometry (ESI‐ITMSn) in positive ion mode. MS2 and MS3 spectra of the compounds were investigated by principal component analysis (PCA) and could be classified by partial least squares – discriminant analysis (PLS‐DA) according to the structures of the oligosaccharides at C‐3 and C‐28 of the saponins. Four minor components with novel structures were found in a previously non‐investigated fraction of QH‐C. The structures of two of these components, J1 and J1a, were predicted by PLS‐DA whereas the structures of the two others, J2 and J3, were only partly predicted. The structures of J1 and J1a were composed of structural elements found in the 34 known saponins whereas a new acyl substituent, not included in the training set used for calibration of the PLS‐DA models, was found in J2 and J3, making these two components outliers. The complete structures of the four components were confirmed by monosaccharide analysis, MSn data and 1H NMR spectroscopy. Copyright © 2008 John Wiley & Sons, Ltd.