bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sensing the dissociation of a polymeric enzyme by means of an engineered intrinsic probe
Authors: Ainciart N. , Zylberman V. , Craig P.O. , Nygaard D. , Bonomi H.R. , Cauerhff A.A. , Goldbaum F.A. 
Published: November 2010

AbstractOne of the most remarkable characteristics of Brucella lumazine synthase (BLS) is its versatility to undergo reversible dissociation and reassociation as a polymeric scaffold. We have proposed a mechanism of dissociation and unfolding of BLS. Using static light scattering (SLS) analysis, we were able to demonstrate that the decameric assembly dissociates into two different conditions [pH 5 or 2M guanidinium chloride (GdnHCl) pH 7] forming stable folded pentamers. The transition from folded pentamers to unfolded monomers by GdnHCl denaturation is highly cooperative and can be measured by different spectroscopic techniques. In this work, we show the successful insertion of an intrinsic probe to study in more detail the equilibria described in previous publications. For that purpose, we performed single‐point mutations of Phe residues 121 and 127, located at the pentamer–pentamer and monomer–monomer interface, respectively, to Trp residues. These mutations produced only a marginal perturbation of the BLS structure. We analyzed the unfolding and stability of the mutants through different techniques: far‐and near‐UV CD, SLS, dynamic light scattering, and fluorescence spectroscopy. The introduced intrinsic probe could be used to gain insights into the detailed folding and assembly mechanism of this protein. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Protein rigidity and thermophilic adaptation
Authors: Radestock Sebastian , Gohlke Holger 
Published: November 2010

AbstractWe probe the hypothesis of corresponding states, according to which homologues from mesophilic and thermophilic organisms are in corresponding states of similar rigidity and flexibility at their respective optimal temperatures. For this, the local distribution of flexible and rigid regions in 19 pairs of homologous proteins from meso‐ and thermophilic organisms is analyzed and related to activity characteristics of the enzymes by constraint network analysis (CNA). Two pairs of enzymes are considered in more detail: 3‐isopropylmalate dehydrogenase and thermolysin‐like protease. By comparing microscopic stability features of homologues with the help of stability maps, introduced for the first time, we show that adaptive mutations in enzymes from thermophilic organisms maintain the balance between overall rigidity, important for thermostability, and local flexibility, important for activity, at the appropriate working temperature. Thermophilic adaptation in general leads to an increase of structural rigidity but conserves the distribution of functionally important flexible regions between homologues. This finding provides direct evidence for the hypothesis of corresponding states. CNA thereby implicitly captures and unifies many different mechanisms that contribute to increased thermostability and to activity at high temperatures. This allows to qualitatively relate changes in the flexibility of active site regions, induced either by a temperature change or by the introduction of mutations, to experimentally observed losses of the enzyme function. As for applications, the results demonstrate that exploiting the principle of corresponding states not only allows for successful thermostability optimization but also for guiding experiments in order to improve enzyme activity in protein engineering. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Effect of flanking residues on the conformational sampling of the internal fusion peptide from Ebola virus
Authors: Jaskierny Adam J. , Panahi Afra , Feig Michael 
Published: November 2010

AbstractFusion peptides mediate viral and host‐cell membrane fusion during viral entry. The monomeric form of the internal fusion peptide from Ebola virus was studied in membrane bilayer and water environments with computer simulations using replica exchange sampling and an implicit solvent description of the environment. Wild‐type Ebola fusion peptide (EFP), the W8A mutant form, and an extended construct with flanking residues were examined. It was found that the monomeric form of wild‐type EFP adopts coil–helix–coil structure with a short helix from residues 8 to 11 mostly sampling orientations parallel to the membrane surface. W8A mutation disrupts the helicity in the N‐terminal region of the peptide and leads to a preference for slightly oblique orientation relative to the membrane surface. The addition of flanking residues also alters the fusion peptide conformation with either a helix–break–helix structure or extended N and C‐termini and reduced membrane insertion. In water, the fusion peptide is found to adopt structures with low helicity. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Reduced metribuzin pollution with phosphatidylcholine–clay formulations
Authors: Undabeytia Tomás , Recio Esther , Maqueda Celia , Morillo Esmeralda , Gómez‐Pantoja Eulalia , Sánchez‐Verdejo Trinidad 
Published: November 2010

AbstractBACKGROUND: Metribuzin is a widely used herbicide that has been identified as a groundwater contaminant. In this study, slow‐release formulations of metribuzin were designed by encapsulating the active ingredient in phosphatidylcholine (PC) vesicles and adsorbing the vesicles onto montmorillonite.RESULTS: The maximum active ingredient content in the slow‐release formulations was 246 g kg−1. Infrared spectroscopy results revealed that the hydrophobic interactions between metribuzin and the alkyl chains on PC were necessary for encapsulation. In addition, water bridges connecting the herbicide and the PC headgroup enhanced the solubility of metribuzin in PC. Adsorption experiments in soils were performed to evaluate the relationship between sorption and leaching. Funnel experiments in a sandy soil revealed that the herbicide was not irreversibly retained in the formulation matrix. In soil column experiments, PC–clay formulations enhanced herbicide accumulation and biological activity in the top soil layer relative to a commercial formulation. PC–clay formulations also reduced the dissipation of metribuzin by a factor of 1.6–2.5.CONCLUSIONS: A reduction in the recommended dose of metribuzin can be achieved by employing PC–clay formulations, which reduces the environmental risk associated with herbicide applications. Moreover, PC and montmorillonite are non‐toxic and do not negatively affect the environment. Copyright © 2010 Society of Chemical Industry
The semi‐geostrophic diagnosis of vertical motion. I: Formulation and coordinate transformations
Authors: Pedder Mike A. , Thorpe Alan J. 
Published: November 2010

AbstractTheoretical considerations suggest that the semi‐geostrophic (SG) omega equation should provide a more accurate diagnosis of vertical velocity than the classical quasi‐geostrophic (QG) omega equation in the presence of significant horizontal variations in static stability and potential vorticity. Only very few previous studies have compared the performance of the two methods applied to either real or simulated data. Furthermore, it is almost certain that such comparisons have been affected by uncertainties associated with transformations between physical and geostrophic momentum (GM) coordinates, these being necessary in order to solve the SG omega equation in a form which retains the conceptual simplicity of the QG omega equation. Here we describe an accurate method of mapping between physical and GM coordinates which is suitable for operating on a large, discrete data base. The result of an inverse mapping is used to measure the accuracy of the method. This is shown to be sensitive to the chosen grid‐point resolution in GM space, which may need to be considerably greater than the given resolution in physical space in order to resolve dynamically significant features in regions of negative geostrophic shear.The SG equations do not apply when the Jacobian of the GM coordinate transformation (J) changes sign within the domain of the analysis. If such a situation occurs with real data then it is necessary to apply an adjustment to the sampled geopotential (or pressure) data, in order to satisfy the condition J > 0 everywhere prior to a SG diagnosis of vertical velocity. A variational approach to this problem is described and tested using data generated by a primitive‐equation model of a developing cyclone.
Can a relaxation technique be used to validate clouds and sulphur species in a GCM?
Authors: Feichter Johann , Lohmann Ulrike 
Published: November 2010

AbstractThe Hamburg version of the European Centre for Medium‐Range Weather Forecasting (ECMWF) general circulation model, ECHAM4, developed for climate studies, is used to study the hydrological cycle and the atmospheric sulphur cycle. A technique, the Newtonian relaxation, is introduced to compare results from the model with measurements of cloud parameters and sulphur species concentrations. The model is forced by ECMWF analyses to simulate September 1993, and results are compared to observations on different spatial and temporal scales: monthly mean horizontal satellite data, daily mean averages at European and Canadian stations and aircraft soundings over the north Atlantic off the Canadian coast. The model is able to reproduce monthly mean horizontal distributions of liquid water path and precipitation. Daily mean precipitation fluxes and the temporal evolution of gaseous and particulate sulphur also agree quite well with observations. Based on this comparison with observations the performance of two different cloud physics parametrizations is discussed. These experiments indicate that variables like relative humidity, cloud cover and precipitation are controlled by the large‐scale dynamics, whereas the cloud water content depends on the parametrization of the cloud microphysics. Coupling of the model‐calculated sulphate mixing ratios to the cloud microphysics improves the model's sulphate distribution but slightly worsens the agreement between calculated and observed precipitation.
Turbulence on the lee side of a mountain range: Aircraft observations during PYREX
Authors: Attié J.‐L. , Druilhet A. , Bénech B. , Durand P. 
Published: November 2010

AbstractThis study presents an analysis of turbulence data from aircraft measurements made during the PYREX experiment. The data were gathered in a central region of the Pyrénées, a mountain‐range with a more or less west‐east orientation which constitutes a major barrier for northerly and southerly flows. The data used come principally from a Merlin IV aircraft which performed about 100 straight‐and‐level 20 km runs perpendicular or parallel to the main mountain‐range axis. The basic turbulence moments are presented. The data from mountain flows with similar upstream conditions were gathered together in order to construct composite two‐dimensional turbulence fields in the vertical plane perpendicular to the axis of the range. These fields clearly show the location of the turbulence areas on the lee side of the mountain range. The turbulent kinetic energy field shows that turbulence is principally produced by a wake effect. On the lee side the profiles of the various turbulence parameters indicate a maximum at an altitude close to the average height of the mountain in a region having both a strong wind shear and a weak lapse rate. Finally, we show that the turbulence observed in this study obeys the universal law σ‐3ωϵλ≈︁ constant, where s̀w is the standard deviation of the vertical velocity, λ the spectral length‐scale and ϵ the dissipation rate of turbulent kinetic energy. The average value of 2.3 found for this constant is comparable to the values found by other authors under various conditions of turbulence, in particular homogeneous turbulence.
Tandem queues for inventory management under random perturbations
Authors: Sobieczky Florian , Rappitsch Gerhard , Stadlober Ernst 
Published: November 2010

AbstractUsing the theory of M/M/1 queues at stationarity, we provide criteria of stability (recurrence) for a stochastic inventory model with an observed selling rate and an optimally chosen buying rate. Optimality is based on the maximum gain under stability, where buying and selling prices, as well as shop‐ and stock‐keeping costs are incorporated into the model. An important aspect is to achieve robustness of the stocking process by minimizing the fluctuation of the predicted gain. This robustness can be achieved by controlling intermediate transfer rates of the assumed stochastic tandem network. Stochastic simulations demonstrate the applicability of the stability criteria under several scenarios of differing intensities of perturbation. Copyright © 2010 John Wiley & Sons, Ltd.
Bayesian calculation of optimal burn‐in time using the joint criteria of cost and delivered reliability
Authors: Ulusoy, Selda Kapan , Mazzuchi Thomas A. , Perlstein Dror 
Published: November 2010

AbstractBurn‐in is a quality control process used to minimize the warranty cost of a product by screening out defective products through prior operation for a period of time before sale. Two decision criteria used to determine the optimal burn‐in time are the maximization of the reliability of the delivered product and the minimization of the total cost, which are composed of the cost of burn‐in process and the cost of warranty claims. Because of uncertainty regarding the underlying lifetime distribution of the product, both the product reliability and the total cost are random variables. In this paper, the uncertainty in reliability and cost is quantified by use of Bayesian analysis. The joint distribution of reliability and cost is inferred from the uncertainty distribution of the parameters of the product lifetime distribution. To incorporate the uncertainty in reliability and cost as well as the tradeoff between them into the selection of optimal burn‐in time, the joint utility function of reliability and cost is constructed using the joint distribution of reliability and cost. The optimal burn‐in time is selected as the time that maximizes the joint utility function. Copyright © 2010 John Wiley & Sons, Ltd.
Identifying elements critical for functional and sustainable professional learning communities
Authors: Richmond Gail , Manokore Viola 
Published: November 2010

AbstractIn this paper, we examined data collected as part of a 5‐year project designed to foster reform‐based urban science teaching through teachers' communities of inquiry. Drawing upon a distributed leadership framework, we analyzed teacher “talk” during professional learning community (PLC) meetings. This analysis yielded five elements: teacher learning and collaboration, community formation, confidence in knowledge of content and guided inquiry, concerns about the impact of accountability measures on teaching and learning, and sustainability of reform. Follow‐up interviews with participants reinforced the importance of these elements. While accountability measures were found to have a significant impact on science teaching, participants were also able to use their PLC‐based experiences to develop strategies to deal with such external constraints. Facilitation and leadership also play key roles in establishing and maintaining PLCs in this urban setting. Finally, we present a revised framework that incorporates the elements we identified to describe those local and systemic factors critical for successful implementation and influence of professional development efforts. © 2010 Wiley Periodicals, Inc. Sci Ed 95: 543–570, 2011
Who wants to have a career in science or math? exploring adolescents' future aspirations by gender and race/ethnicity
Authors: Riegle‐Crumb Catherine , Moore Chelsea , Ramos‐Wada Aida 
Published: November 2010

AbstractOur study utilizes data from a national cohort of eighth‐grade students to consider how different gender and racial/ethnic subgroups compare to White males in their likelihood to aspire toward a science or math occupation and examine the roles that self‐concept, enjoyment, and achievement may play in shaping disparities at this early point in occupational trajectories. We find that the importance of enjoyment, self‐concept, and achievement in explaining disparities in science career aspirations relative to White males varies according to the female subgroup considered, such that no singular story applies to females across different racial/ethnic backgrounds. For math, White and Hispanic females remain approximately half as likely as White males to aspire to a math occupation regardless of all indicators we consider. Finally, Black and Hispanic adolescent boys have generally comparable aspirations toward future careers in science and math as their White male peers, despite notably large differences in achievement. We discuss implications of our results for future research on equity. © 2010 Wiley Periodicals, Inc. Sci Ed 95: 458–476, 2011
New nonlinear anti‐seismic steel device for the increasing the seismic capacity of multi‐storey reinforced concrete frames
Authors: Papadopoulos Panikos 
Published: November 2010

SUMMARYIn order to increase the seismic capacity of multi‐storey planar reinforced concrete (r/c) frames, a new metal frictional device, which the capacity of a restricted rotation around the horizontal axis perpendicular to the vertical frame plane, is presented. The proposed steel device is joined to the four joints of the vertical floor span of the frame via four diagonal steel dual‐hinge bars. During the above restricted rotation, frictional forces develop, due to a suitable synthetic material that is inserted into the rotational frictional connections. When the horizontal relative floor displacement, between two floors, exceeds a desired specific value, then the proposed device locks and the diagonal steel bar becomes fully activated to tension, adding significant additional strength to the frame. This device is installed in a vertical floor span, but it is worth noting that the devices can be placed at floor spans that are not on the same vertical line. The nonlinear numerical (static/dynamic) analyses carried out in the present article, shows that the proposed devices contribute in increase of the lateral stiffness of the frame, the lateral strength of the frame in the inelastic area and the absorption of the inserted seismic energy. Furthermore, this device protects the diagonal steel bars from the buckling or from premature failure of compression. In addition, the proposed device is designed in a way that allows it to operate effectively under large horizontal relative floor displacements due to the cyclic dynamic loads, and can be used instead of the structural r/c walls. Copyright © 2010 John Wiley & Sons, Ltd.
A New 3D Supramolecular Manganese(II) Complex Constructed from Benzimidazole‐5,6‐dicarboxylate and Oxalate: Synthesis, Structural, and Magnetic Properties
Authors: Geng Jin‐Peng , Wang Zhao‐Xi , Wu Qiong‐Fang , Li Ming‐Xing , Xiao Hong‐Ping 
Published: November 2010

AbstractA new manganese(II) complex [Mn3(bidc)2(C2O4)(H2O)10]n (1) (bidc = benzimidazole‐5,6‐dicarboxylate) was synthesized and characterized by X‐ray crystallography. X‐ray diffraction shows that complex 1 has a neutral, one‐dimensional (1D) brick wall chain structure. With the intramolecular and intermolecular hydrogen bonding interactions, the adjacent chains are joined into a 3D suparmolecular architecture. IR spectroscopy and variable temperature magnetic susceptibility measurements were made, which indicated weak antiferromagnetic coupling between the MnII ions in complex 1.
On the Reactivity of the Platina‐β‐diketone [Pt2{(COMe)2H}2(μ‐Cl)2] Towards Ph2PCH2CH2CH2SOxPh (x = 0, 2)
Authors: Block Michael , Bette Martin , Wagner Christoph , Steinborn Dirk 
Published: November 2010

AbstractThe reaction of the electronically unsaturated platina‐β‐diketone [Pt2{(COMe)2H}2(μ‐Cl)2] (1) with Ph2PCH2CH2CH2SPh (2) leads selectively to the formation of the acetyl(chlorido) platinum(II) complex (SP‐4‐3)‐[Pt(COMe)Cl(Ph2PCH2CH2CH2SPh‐κP,κS)] (4) having the γ‐phosphinofunctionalized propyl phenyl sulfide coordinated in a bidentate fashion (κP,κS). In boiling benzene complex 4 undergoes decarbonylation yielding the methyl(chlorido) platinum(II) complex (SP‐4‐3)‐[PtMeCl(Ph2PCH2CH2CH2SPh‐κP,κS)] (6). However, the reaction of 1 with the analogous γ‐diphenylphosphinofunctionalized propyl phenyl sulfone Ph2PCH2CH2CH2SO2Ph (3) affords the acetyl(chlorido) platinum(II) complex (SP‐4‐4)‐[Pt(COMe)Cl(Ph2PCH2CH2CH2SO2Ph‐κP)2] (5). In boiling benzene complex 5 undergoes a CO extrusion yielding (SP‐4‐4)‐[PtMeCl(Ph2PCH2CH2CH2SO2Ph‐κP)2] (8) whereas in presence of 1 the formation of the carbonyl complex (SP‐4‐3)‐[PtMeCl(CO)(Ph2PCH2CH2CH2SO2Ph‐κP)] (7) is observed. Addition of Ag[BF4] to complex 5 leads to the formation of the cationic methyl(carbonyl) platinum(II) complex (SP‐4‐1)‐[PtMe(CO)(Ph2PCH2CH2CH2SO2Ph‐κP)2][BF4] (9). All complexes were characterized by microanalysis and NMR spectroscopy (1H, 13C, 31P) and complexes 4 and 6 additionally by single‐crystal X‐ray diffraction analyses.
A pictorial review of benign hepatocellular nodular lesions: comprehensive radiological assessment incorporating the concept of anomalous portal tract syndrome
Authors: Ueda Takuya , Starkey Jay , Mori Kensaku , Fukunaga Kiyoshi , Shimofusa Ryota , Motoori Ken , Minami Manabu , Kondo Fukuo 
Published: November 2010

AbstractBackground/purposeAlthough the pathological categorization system advocated by the International Working Party (IWP) on Terminology has been helpful in categorizing benign hepatocellular lesions, the diverse clinicopathological features of the lesions still cause confusion of diagnosis in clinical settings. Recently, an integrated disease concept termed “anomalous portal tract syndrome” (APTS) has been proposed as a congenital anomaly of the portal tract, being a single unifying etiological factor underlying the disorder. In this article, we discuss the radiological features of benign nodular hepatocellular lesions incorporated in the concept of APTS.MethodsWe systematically reviewed the literature on benign hepatocellular lesions based on the concept of APTS, as well as standard IWP terminology. For this pictorial review, we selected six representative cases and assessed the radiological features of the cases based on the concept of APTS.ResultsThe comprehensive assessment based on APTS enabled the systematic categorization of benign hepatocellular lesions, including nodular regenerative hyperplasia, large regenerative nodules, partial nodular transformation, focal nodular hyperplasia, and hepatocellular adenoma, and was helpful in understanding the overlapping features of these lesions.ConclusionsAlthough the disease concept of APTS is still evolving, it is nonetheless helpful in comprehensively understanding the clinicopathological and radiological features of various benign hepatocellular lesions.
Klüver Bucy syndrome following hypoglycaemic coma in a patient with glycogen storage disease type Ib
Authors: Boudjemline Alix Mollet , Isapof Arnaud , Witas Jean‐Bernard , Petit François M. , Gajdos Vincent , Labrune Philippe 
Published: November 2010

AbstractPatients with type I glycogen storage disease (GSD) have poor tolerance to fasting, sometimes less than 3 hours during infancy. Even though most patients are able, as they get older, to tolerate a longer fasting period, they are at permanent risk for fast‐induced hypoglycaemia, even in adulthood. Klüver Bucy syndrome, is characterized by psychic blindness (inability to recognize familiar objects), hypermetamorphosis (strong tendency to react to visual stimulus), increased oral exploration, placidity, indiscriminate hyper‐sexuality and change in dietary habits. In this case report, we describe the development of Klüver Bucy syndrome in a 28‐year‐old man with type Ib GSD, following prolonged and severe hypoglycaemia triggered by a common respiratory infection.