bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bayesian inference of a lake water quality model by emulating its posterior density
Authors: Dietzel A. , Reichert P. 
Published: September 2014

AbstractWe use a Gaussian stochastic process emulator to interpolate the posterior probability density of a computationally demanding application of the biogeochemical‐ecological lake model BELAMO to accelerate statistical inference of deterministic model and error model parameters. The deterministic model consists of a mechanistic description of key processes influencing the mass balance of nutrients, dissolved oxygen, organic particles, and phytoplankton and zooplankton in the lake. This model is complemented by a Gaussian stochastic process to describe the remaining model bias and by Normal, independent observation errors. A small subsample of the Markov chain representing the posterior of the model parameters is propagated through the full model to get model predictions and uncertainty estimates. We expect this approximation to be more accurate at only slightly higher computational costs compared to using a Normal approximation to the posterior probability density and linear error propagation to the results as we did in an earlier paper. The performance of the two techniques is compared for a didactical example as well as for the lake model. As expected, for the didactical example, the use of the emulator led to posterior marginals of the model parameters that are closer to those calculated by Markov chain simulation using the full model than those based on the Normal approximation. For the lake model, the new technique proved applicable without an excessive increase in computational requirements, but we faced challenges in the choice of the design data set for emulator calibration. As the posterior is a scalar function of the parameters, the suggested technique is an alternative to the emulation of a potentially more complex, structured output of the simulation model that allows for the use of a less case‐specific emulator. This is at the cost that still the full model has to be used for prediction (which can be done with a smaller, approximately independent subsample of the Markov chain).
With or against the tide: The influence of bed form asymmetry on the formation of macroturbulence and suspended sediment patterns
Authors: Kwoll E. , Becker M. , Winter C. 
Published: September 2014

AbstractThis study examines tide‐dependent variations in the formation and dynamics of suspended sediment patterns coupled to mean flow and turbulence above asymmetric bed forms. In the Danish Knudedyb inlet, very large primary bed forms remain ebb‐oriented during a tidal cycle while smaller superimposed bed forms reverse direction with each tidal phase. Hydroacoustic in situ observations reveal pronounced differences in suspended sediment transport patterns between tidal phases caused by the relative orientation of primary bed forms and the mean tidal flow and flow unsteadiness during a single tidal phase. When flow and primary bed form orientation are aligned, water‐depth‐scale macroturbulence develops in the bed form lee‐sides in the presence of flow separation. Macroturbulent flow structures occur at high flow stages and are coupled to increased amounts of sediment in suspension. When flow and bed form orientation are opposed no evidence of flow separation associated with primary bed forms is found. Sediment‐laden macroturbulence at high flow velocities is of a smaller scale and attributed to the superimposed secondary bed forms. The flow structures are advected along the primary bed form stoss‐side (temporary hydraulic lee‐side). The steep primary bed form lee‐side (temporary hydraulic stoss‐side) however, limits transport capabilities beyond the scale of primary bed forms.
Multiobjective optimization of cluster‐scale urban water systems investigating alternative water sources and level of decentralization
Authors: Newman J. P. , Dandy G. C. , Maier H. R. 
Published: September 2014

AbstractIn many regions, conventional water supplies are unable to meet projected consumer demand. Consequently, interest has arisen in integrated urban water systems, which involve the reclamation or harvesting of alternative, localized water sources. However, this makes the planning and design of water infrastructure more difficult, as multiple objectives need to be considered, water sources need to be selected from a number of alternatives, and end uses of these sources need to be specified. In addition, the scale at which each treatment, collection, and distribution network should operate needs to be investigated. In order to deal with this complexity, a framework for planning and designing water infrastructure taking into account integrated urban water management principles is presented in this paper and applied to a rural greenfield development. Various options for water supply, and the scale at which they operate were investigated in order to determine the life‐cycle trade‐offs between water savings, cost, and GHG emissions as calculated from models calibrated using Australian data. The decision space includes the choice of water sources, storage tanks, treatment facilities, and pipes for water conveyance. For each water system analyzed, infrastructure components were sized using multiobjective genetic algorithms. The results indicate that local water sources are competitive in terms of cost and GHG emissions, and can reduce demand on the potable system by as much as 54%. Economies of scale in treatment dominated the diseconomies of scale in collection and distribution of water. Therefore, water systems that connect large clusters of households tend to be more cost efficient and have lower GHG emissions. In addition, water systems that recycle wastewater tended to perform better than systems that captured roof‐runoff. Through these results, the framework was shown to be effective at identifying near optimal trade‐offs between competing objectives, thereby enabling informed decisions to be made when planning water systems for greenfield developments.
A comparison of the effects of CIR‐ and CME‐induced geomagnetic activity on thermospheric densities and spacecraft orbits: Statistical studies
Authors: Chen Guang‐ming , Xu Jiyao , Wang Wenbin , Burns Alan. G. 
Published: September 2014

AbstractEnhanced energy input from the magnetosphere to the upper atmosphere during geomagnetic storms has a profound effect on thermospheric density and consequently near‐Earth satellite orbit decay. These geomagnetic storms are caused by two different processes. The first is coronal mass ejections (CMEs) and the second is corotating interaction regions (CIRs). CME‐driven storms are characterized by large maximum energy input but relatively short duration, whereas CIR‐driven storms have relatively small maximum energy input but are of a considerably longer duration. In this paper we carried out a statistical study to assess the relative importance of each kind of storm to satellite orbital decay. The results demonstrate that CIR storms have a slightly larger effect on total orbital decay than CME storms do in a statistical sense. During the declining phase and the minimum years of a solar cycle, CIR storms occur frequently and quasiperiodically. These storms have a large effect on thermospheric densities and satellite orbits because of their relatively long duration. Thus, it is important to fully understand their behavior and impact.
Dynamical effects during compaction band formation affecting their spatial periodicity
Authors: Cecinato Francesco , Gajo Alessandro 
Published: September 2014

AbstractCompaction bands (CBs) are responsible for significant anisotropy alterations of permeability in geological materials; hence, understanding their formation conditions appears of key importance to all applications involving fluid extraction/injection from/into the ground. While most of the available models to understand CB formation are focused on interpreting the onset of a single CB, little effort has been so far dedicated to understand the documented periodicity of CBs. In this paper, the role of dynamical effects in inducing the post onset evolution of CBs is analyzed by means of a dedicated model for porous media with compressible constituents, with reference to a horizontal layer of sandy, water‐saturated material. Elastic waves are generated as a first CB occurs due to sudden, localized volumetric collapse. If the waves are reflected at the interface with a softer material or with a previously formed CB, they produce significant local effective stress concentrations, which can promote the formation of further CBs in a cascade fashion, according to a regular geometric pattern. The spatial distribution of dynamically generated CBs, as well as the extent of the phenomenon, depends on the geometry of the domain and on the material's permeability. Sensitivity analysis is also performed to assess the key properties that promote dynamical CB in situ formation, identifying as the most influential conditions large stratum stiffness (increasing with depth) and the presence of softer layers. In contrast, the presence of less permeable and/or stiffer layers is not believed to play a major role in the proposed mechanism.
A dynamic watershed model for determining the effects of transient storage on nitrogen export to rivers
Authors: Chen Dingjiang , Hu Minpeng , Dahlgren Randy A. 
Published: September 2014

AbstractLegacy anthropogenic nitrogen (N) has been suggested as a major cause for increasing riverine N exports despite significant declines in anthropogenic N inputs in many regions. However, little quantitative knowledge exists concerning the contribution of the legacy N pool to riverine N export. This study developed a dynamic watershed N delivery model to address the role of transient storage of anthropogenic N inputs on riverine N flux. Employing simple mass balance and equivalent substitution rules, the model expresses the transient storage of legacy N mass with a term that combines the previous one year's riverine total N (TN) flux, relevant explanatory variables, and unknown parameters, enabling us to inversely calibrate the model parameters from measurable variables using Bayesian statistics. The model efficacy was demonstrated through application to the Yong'an River watershed in eastern China based on a 31 year record (1980–2010) of riverine TN fluxes. The model can quantify annual transient storage of legacy N and its resulting contribution to annual riverine N flux. The model also allows partitioning of the complete long‐term mass balance for the fate (e.g., transient storage, riverine export, and loss/retention by denitrification, biomass uptake and wood product export) of annual anthropogenic N inputs. To further improve the model, various N input‐output processes can be specified and long‐term measurements of N fates are required to further verify the model results. This study demonstrates the need to consider transient storage effects as an improvement to current watershed models and for developing and assessing N pollution control measures.
Quantification of Protein Kinase Enzymatic Activity in Unfractionated Cell Lysates Using CSox‐Based Sensors
Authors: Beck Jon R. , Peterson Laura B. , Imperiali Barbara , Stains Cliff I. 
Published: September 2014

AbstractDefining perturbations in protein kinase activity within biological samples can provide insight into disease mechanisms as well as potential targets for drug development. In this article, we present a method that utilizes a phosphorylation‐sensitive amino acid, termed CSox, to afford kinase‐selective biosensors capable of reporting on enzymatic activity directly in biological samples. These sensors produce an increase in fluorescence in response to phosphorylation of an amino acid residue adjacent to CSox. Probes can be designed for either serine/threonine or tyrosine kinases, and analysis can be performed using standard fluorescence equipment. The procedures provided herein represent our optimized protocols for the design, validation, and application of CSox‐based protein kinase activity sensors. Curr. Protoc. Chem. Biol. 6:135‐156 © 2014 by John Wiley & Sons, Inc.
Tandem Synthesis of Polysubstituted Pyridines via the Indium(III)‐Triflate‐Catalyzed Cycloaddition/Oxidative Aromatization of Blaise Reaction Intermediates with α,β‐Unsaturated Ketones
Authors: Xuan Zi , Rathwell Kris , Lee Sang‐gi 
Published: September 2014

AbstractA tandem one‐pot method for the construction of polysubstituted pyridines with complete control of the substitution pattern has been developed. The zinc bromide β‐enamino ester intermediates of the Blaise reaction of simple nitriles with a Reformatsky reagent undergo Michael addition with conjugated ketones in the presence of a catalytic amount of In(OTf)3. Final intramolecular cyclization and oxidative aromatization yields polysubstituted pyridines in this tandem one‐pot cascade.
Lumineszenzsteigerung bei Lanthanoid‐dotierten aufkonvertierenden Nanopartikeln
Authors: Han Sanyang , Deng Renren , Xie Xiaoji , Liu Xiaogang 
Published: September 2014

AbstractEs gibt ein großes Interesse an der Erforschung von Lanthanoid‐dotierten aufkonvertierenden Nanopartikeln aufgrund ihrer optischen Eigenschaften und ihrem breitgefächerten Anwendungspotential von der biologischen Bildgebung bis hin zur photodynamischen Therapie. Trotz der beachtlichen Fortschritte, die im letzten Jahrzehnt erzielt wurden, wird das Gebiet durch erhebliche experimentelle Probleme im Zusammenhang mit geringen Umwandlungswirkungsgraden der Aufkonversion behindert. Neuere experimentelle und theoretische Studien zu aufkonvertierenden Nanopartikeln führten jedoch zur Entwicklung mehrerer wirksamer Methoden zur Steigerung der Aufkonversionslumineszenz, die tiefgreifende Auswirkungen auf eine Reihe von Anwendungen haben könnten. In diesem Kurzaufsatz beschreiben wir die zugrundeliegenden Prinzipien der Steuerung der Energieübertragung über die Dotierung mit Lanthanoid, geben einen Überblick über die wesentlichen Fortschritte und die Hauptherausforderungen bei der Verbesserung der Aufkonversionslumineszenz und betrachten die voraussichtlichen Ausrichtungen der zukünftigen Forschung auf dem Gebiet.
X‐Ray Emission Spectroscopy: A Spectroscopic Measure for the Determination of NO Oxidation States in Fe–NO Complexes
Authors: Lu Tsai‐Te , Weng Tsu‐Chien , Liaw Wen‐Feng 
Published: September 2014

AbstractExtensive study of the electronic structure of Fe‐NO complexes using a variety of spectroscopic methods was attempted to understand how iron controls the binding and release of nitric oxide. The comparable energy levels of NO π* orbitals and Fe 3d orbitals complicate the bonding interaction within FeNO complexes and puzzle the quantitative assignment of NO oxidation state. Enemark–Feltham notation, {Fe(NO)x}n, was devised to circumvent this puzzle. This 40‐year puzzle is revisited using valence‐to‐core X‐ray emission spectroscopy (V2C XES) in combination with computational study. DFT calculation establishes a linear relationship between ΔEσ2s*‐σ2p of NO and its oxidation state. V2C Fe XES study of FeNO complexes reveals the ΔEσ2s*‐σ2p of NO derived from NO σ2s*/σ2p→Fe1s transitions and determines NO oxidation state in FeNO complexes. Quantitative assignment of NO oxidation state will correlate the feasible redox process of nitric oxide and Fe‐nitrosylation biology.
Advances in Anion Supramolecular Chemistry: From Recognition to Chemical Applications
Authors: Evans Nicholas H. , Beer Paul D. 
Published: September 2014

AbstractSince the start of this millennium, remarkable progress in the binding and sensing of anions has been taking place, driven in part by discoveries in the use of hydrogen bonding, as well as the previously under‐exploited anion–π interactions and halogen bonding. However, anion supramolecular chemistry has developed substantially beyond anion recognition, and now encompasses a diverse range of disciplines. Dramatic advance has been made in the anion‐templated synthesis of macrocycles and interlocked molecular architectures, while the study of transmembrane anion transporters has flourished from almost nothing into a rapidly maturing field of research. The supramolecular chemistry of anions has also found real practical use in a variety of applications such as catalysis, ion extraction, and the use of anions as stimuli for responsive chemical systems.
Palladium‐Catalyzed Annulation of Diarylamines with Olefins through CH Activation: Direct Access to N‐Arylindoles
Authors: Sharma Upendra , Kancherla Rajesh , Naveen Togati , Agasti Soumitra , Maiti Debabrata 
Published: September 2014

AbstractA palladium‐catalyzed dehydrogenative coupling between diarylamines and olefins has been discovered for the synthesis of substituted indoles. This intermolecular annulation approach incorporates readily available olefins for the first time and obviates the need of any additional directing group. An ortho palladation, olefin coordination, and β‐migratory insertion sequence has been proposed for the generation of olefinated intermediate, which is found to produce the expected indole moiety.
Solid‐State Structure of a Li/F Carbenoid: Pentafluoroethyllithium
Authors: Waerder Benedikt , Steinhauer Simon , Neumann Beate , Stammler Hans‐Georg , Mix Andreas , Vishnevskiy Yury V. , Hoge Berthold , Mitzel Norbert W. 
Published: September 2014

AbstractLithium carbenoids are versatile compounds for synthesis owing to their intriguing ambiphilic behavior. Although this class of compounds has been known for several years, few solid‐state structures exist because of their high reactivity and often low thermal stability. Using cryo X‐ray techniques, we were now able to elucidate the first solid‐state structure of a Li/F alkyl carbenoid, pentafluoroethyllithium (LiC2F5), finally yielding a prototype for investigating structure—reactivity relationships for this class of molecules. The compound forms a diethyl ether‐solvated dimer bridged by a rare C–F–Li link. Complementary NMR spectroscopy studies in solution show dynamic processes and indicate rapid exchange of starting material and product. Theoretical investigations help to understand the formation of the observed unusual structural motif.
Efficient Access to Substituted Silafluorenes by Nickel‐Catalyzed Reactions of Biphenylenes with Et2SiH2
Authors: Breunig Jens Michael , Gupta Puneet , Das Animesh , Tussupbayev Samat , Diefenbach Martin , Bolte Michael , Wagner Matthias , Holthausen Max C. , Lerner Hans‐Wolfram 
Published: September 2014

AbstractThe reaction of biphenylene (1) with Et2SiH2 in the presence of [Ni(PPhMe2)4] results in the formation of a mixture of 2‐diethylhydrosilylbiphenyl [2(Et2HSi)] and 9,9,‐diethyl‐9‐silafluorene (3). Silafluorene 3 was isolated in 37.5 % and 2(Et2HSi) in 36.9 % yield. The underlying reaction mechanism was elucidated by DFT calculations. 4‐Methyl‐9,9‐diethyl‐9‐silafluorene (7) was obtained selectively from the [Ni(PPhMe2)4]‐catalyzed reaction of Et2SiH2 and 1‐methylbiphenylene. By contrast, no selectivity could be found in the Ni‐catalyzed reaction between Et2SiH2 and the biphenylene derivative that bears tBu substituents in the 2‐ and 7‐positions. Therefore, two pairs of isomers of tBu‐substituted silafluorenes and of the related diethylhydrosilylbiphenyls were formed in this reaction. However, a subsequent dehydrogenation of the diethylhydrosilylbiphenyls with Wilkinson’s catalyst yielded a mixture of 2,7‐di‐tert‐butyl‐9,9‐diethyl‐9‐silafluorene (8) and 3,6‐di‐tert‐butyl‐9,9‐diethyl‐9‐silafluorene (9). Silafluorenes 8 and 9 were separated by column chromatography.
Explicit and Iterative Methods for Solving the Matrix Equation AV + BW = EVF + C
Authors: Ramadan Mohamed A. , Bayoumi Ahmed M. E. 
Published: September 2014

AbstractIn this paper, we consider explicit and iterative methods for solving the Generalized Sylvester matrix equation AV + BW = EVF + C. Based on the use of Kronecker map and Sylvester sum some lemmas and theorems are stated and proved where explicit and iterative solutions are obtained. The proposed methods are illustrated by numerical example. The obtained results show that the methods are very neat and efficient.
Perfusion culture‐induced template‐assisted assembling of cell‐laden microcarriers is a promising route for fabricating macrotissues
Authors: Wang Xiu , Jiao Qingling , Zhang Songjie , Ye Zhaoyang , Zhou Yan , Tan Wen‐Song 
Published: September 2014

AbstractMass transfer limitation in conventional top‐down tissue engineering makes it impossible to fabricate large size viable tissue replacements. In the present study, we aimed at performing a systemic investigation of the assembling process in perfusion culture for fabricating centimeter‐scale macrotissues from cell‐laden microcarriers following a bottom‐up modular approach. Cells (human fibroblasts, human mesenchymal stem cells, or HepG2 cells) were seeded onto microcarriers (Cytopore‐2 or CultiSpher S) in spinner flasks and cultured for 14 days and subsequently transferred to a perfusion chamber for assembling. It was found that growth of different cells on different microcarriers varied and aggregation of cell‐laden microcarriers was favored with CultiSpher S. After perfusion culture for 14 days, while all microtissues could assemble into integral macrotissues, macrotissues of HepG2 cells were structurally most inferior and the assembling of cell‐laden CultiSpher S led to a significant shrinkage. By designing perfusion chamber and using agar‐based templates, tubular, disc, and alphabetic letter‐shaped macrotissues could be easily fabricated, suggesting template‐assisted assembling. Importantly, it was revealed that there existed both optimal perfusion culture time (21 days) and packing condition (1/4 compression) for the assembling of microtissues. This study lays a solid foundation for future applications of this microtissue assembling technique in tissue engineering.
Effect of laparoscopic splenectomy on portal haemodynamics in patients with liver cirrhosis and portal hypertension
Authors: Kawanaka H , Akahoshi T , Kinjo N , Iguchi T , Ninomiya M , Yamashita Y-I , Ikegami T , Yoshizumi T , Shirabe K , Maehara Y 
Published: September 2014

AbstractBackgroundThe effect of splenomegaly in patients with liver cirrhosis and portal hypertension is not fully understood. This study was designed to determine the effect of laparoscopic splenectomy on portal haemodynamics in these patients.MethodsPatients with liver cirrhosis and portal hypertension who underwent laparoscopic splenectomy in Kyushu University Hospital from January 2006 to March 2009 were evaluated retrospectively. Correlations between splenic size and portal haemodynamics, and changes in portal haemodynamics and in levels of the vasoactive agents endothelin (ET) 1 and nitric oxide metabolites (NOx) before and 7–10 days after laparoscopic splenectomy were analysed.ResultsPortal venous (PV) blood flow, PV cross-sectional area and PV congestion index correlated significantly with splenic size (P &lt; 0·050). All three were significantly reduced following splenectomy in 59 patients. The hepatic venous pressure gradient, measured in 18 patients, decreased by 25 per cent after splenectomy (P &lt; 0·001). Portal vascular resistance was also reduced, by 21 per cent (P = 0·009). The peripheral blood concentration of ET-1 decreased from 2·95 to 2·11 pg/ml (P &lt; 0·001), and that of NOx tended to decrease (from 29·2 to 25·0 pg/ml; P = 0·068). In hepatic venous blood, the level of ET-1 decreased from 2·37 to 1·83 pg/ml (P = 0·006), whereas NOx concentration tended to increase (from 24·5 to 30·9 pg/ml; P = 0·067).ConclusionIn patients with liver cirrhosis and portal hypertension, splenectomy reduced portal venous pressure. A decrease in splanchnic blood flow, by eliminating splenic blood flow, and reduction in intrahepatic vascular resistance, by normalizing hepatic concentrations of ET-1 and NOx, may both have contributed.