bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controls of surface soil moisture spatial patterns and their temporal stability in a semi‐arid steppe
Authors: Zhao Y. , Peth S. , Wang X. Y. , Lin H. , Horn R. 
Published: April 2010

AbstractTemporal stability of soil moisture spatial patterns has important implications for optimal soil and water management and effective field monitoring. The aim of this study was to investigate the temporal stability of soil moisture spatial patterns over four plots of 105 m × 135 m in grid size with different grazing intensities in a semi‐arid steppe in China. We also examined whether a time‐stable location can be identified from causative factors (i.e. soil, vegetation, and topography). At each plot, surface soil moisture (0–6 cm) was measured about biweekly from 2004 to 2006 using 100 points in each grid. Possible controls of soil moisture, including soil texture, organic carbon, bulk density, vegetation coverage, and topographic indices, were determined at the same grid points. The results showed that the spatial patterns of soil moisture were considerably stable over the 3‐y monitoring period. Soil moisture under wet conditions (averaged volumetric moisture contents > 20%) was more stable than that under dry ($\bar{\theta}_{j, t} < 10\%$) or moist ($\def\endash{\hbox{--}} \bar{\theta}_{j, t} = 10\endash 20\%$) conditions. The best representative point for the whole field identified in each plot was accurate in representing the field mean moisture over time (R2 ≥ 0·97; p < 0·0001). The degree of temporal persistence varied with grazing intensity, which was partly related to grazing‐induced differences in soil and vegetation properties. The correlation analysis showed that soil properties, and to a lesser extent vegetation and topographic properties, were important in controlling the temporal stability of soil moisture spatial patterns in this relatively flat grassland. Response surface regression analysis was used to quantitatively identify representative monitoring locations a priori from available soil‐plant parameters. This allows appropriate selection of monitoring locations and enhances efficiency in managing soil and water resources in semi‐arid environments. Copyright © 2010 John Wiley & Sons, Ltd.
Soil saturation index of salt marshes subjected to spring‐neap tides: a new variable for describing marsh soil aeration condition
Authors: Xin Pei , Gibbes Badin , Li Ling , Song Zhiyao , Lockington David 
Published: April 2010

AbstractOrganized spatial distribution of plants (plant zonation) in salt marshes has been linked to the soil aeration condition in the rhizosphere through simplistic tidal inundation parameters. Here, a soil saturation index (ratio of saturation period to tidal period at a soil depth) is introduced to describe the soil aeration condition. This new index captures the effects of not only the tidal inundation period and frequency but also the flow dynamics of groundwater in the marsh soil. One‐dimensional numerical models based on saturated flow with the Boussinesq approximations and a two‐dimensional variably saturated flow model were developed to explore the behaviour of this new soil aeration variable under the influence of spring‐neap tides. Simulations revealed two characteristic zones of soil aeration across the salt marsh: a relatively well aerated near‐creek zone and a poorly aerated interior zone. In the near‐creek zone, soils undergo periodic wetting and drying as the groundwater table fluctuates throughout the spring‐neap cycle. In the interior, the soil remains largely water saturated except for neap tide periods when limited drainage occurs. Although such a change of soil aeration condition has been observed in previous numerical simulations, the soil saturation index provides a clear delineation of the zones that are separated by an ‘inflexion point’ on the averaged index curve. The results show how the saturation index represents the effects of soil properties, tidal parameters and marsh platform elevation on marsh soil aeration. Simulations of these combined effects have not been possible with traditional tidal inundation parameters. The saturation index can be easily derived using relatively simple models based on five non‐dimensional variables. Copyright © 2010 John Wiley & Sons, Ltd.
Hydraulic parameter estimations of a 2D model validated with sedimentological findings in the point bar environment
Authors: Alho Petteri , Mäkinen Joni 
Published: April 2010

AbstractThere have been a number of flume tests of flow round bends with idealized geometry and recently hydraulic simulations of such experiment. However, studies of hydraulic models in natural river bend are rather limited because of greater complexity of the flow characteristics and lack of detailed data. In this article, we study how 2D hydraulic model and raster‐based hydraulic parameter calculations predict flow characteristics on the natural point bar environment. We will compare calculations of various hydraulic parameters (velocity, bed shear stress and stream power) by the 2D model and the associated sedimentology of the point bars. As a result of comparison, the usability of the 2D model for flow‐form‐product relationship predictions will be evaluated in natural river bend environment. The study shows that the 2D model can be generally utilized to predict the flood‐generated flow‐form‐product relationship in coarse‐grained and structurally complex point bar environments with sand‐dominated bedload. For example, point bar sections submerged in water depths greater than 50 cm showed a relatively good match laterally between the model and sedimentological estimations. Furthermore, this approach allows us to estimate flood processes on a local scale in similar point bar environments with ${\sim}1:50$ width–length ratio. The flow direction estimates of the 2D model coincided relatively well with the sedimentological estimations on the bar head. However, flow directions on the downstream section could not be modelled because the 2D model cannot handle the helicoidal flow of the river bend. Copyright © 2010 John Wiley & Sons, Ltd.
Autocrine fibroblast growth factor 18 mediates dexamethasone‐induced osteogenic differentiation of murine mesenchymal stem cells
Authors: Hamidouche Zahia , Fromigué Olivia , Nuber Ulrike , Vaudin Pascal , Pages Jean‐Christophe , Ebert Regina , Jakob Franz , Miraoui Hichem , Marie Pierre J. 
Published: April 2010

AbstractThe potential of mesenchymal stem cells (MSC) to differentiate into functional bone forming cells provides an important tool for bone regeneration. The identification of factors capable of promoting osteoblast differentiation in MSCs is therefore critical to enhance the osteogenic potential of MSCs. Using microarray analysis combined with biochemical and molecular approach, we found that FGF18, a member of the FGF family, is upregulated during osteoblast differentiation induced by dexamethasone in murine MSCs. We showed that overexpression of FGF18 by lentiviral (LV) infection, or treatment of MSCs with recombinant human (rh)FGF18 increased the expression of the osteoblast specific transcription factor Runx2, and enhanced osteoblast phenotypic marker gene expression and in vitro osteogenesis. Molecular silencing using lentiviral shRNA demonstrated that downregulation of FGFR1 or FGFR2 abrogated osteoblast gene expression induced by either LV‐FGF18 or rhFGF18, indicating that FGF18 enhances osteoblast differentiation in MSCs via activation of FGFR1 or FGFR2 signaling. Biochemical and pharmacological analyses showed that the induction of phenotypic osteoblast markers by LV‐FGF18 is mediated by activation of ERK1/2‐MAPKs and PI3K signaling in MSCs. These results reveal that FGF18 is an essential autocrine positive regulator of the osteogenic differentiation program in murine MSCs and indicate that osteogenic differentiation induced by FGF18 in MSCs is triggered by FGFR1/FGFR2‐mediated ERK1/2‐MAPKs and PI3K signaling. J. Cell. Physiol. 224: 509–515, 2010. © 2010 Wiley‐Liss, Inc.
Analysis of 5S rDNA organization and variation in polyploid hybrids from crosses of different fish subfamilies
Authors: Qin Qinbo , He Weiguo , Liu Shaojun , Wang Jing , Xiao Jun , Liu Yun 
Published: April 2010

AbstractIn this article, sequence analysis of the coding region (5S) and adjacent nontranscribed spacer (NTS) were conducted in red crucian carp (RCC), blunt snout bream (BSB), and their polyploid offspring. Three monomeric 5S rDNA classes (designated class I: 203 bp; class II: 340 bp; and class III: 477 bp) of RCC were characterized by distinct NTS types (designated NTS‐I, II, and III for the 83, 220, and 357 bp monomers, respectively). In BSB, only one monomeric 5S rDNA was observed (designated class IV: 188 bp), which was characterized by one NTS type (designated NTS‐IV: 68 bp). In the polyploid offspring, the tetraploid (4nRB) hybrids partially inherited 5S rDNA classes from their female parent (RCC); however, they also possessed a unique 5S rDNA sequence (designated class I‐L: 203 bp) with a novel NTS sequence (designated NTS‐I‐L: 83 bp). The characteristic paternal 5S rDNA sequences (class IV) were not observed. The 5S rDNA of triploid (3nRB) hybrids was completely inherited from the parental species, and generally preserved the parental 5S rDNA structural organization. These results first revealed the influence of polyploidy on the organization and evolution of the multigene family of 5S rDNA of fish, and are also useful in clarifying aspects of vertebrate genome evolution. J. Exp. Zool. (Mol. Dev. Evol.) 314B:403–411 2010. © 2010 Wiley‐Liss, Inc.
Photodegradation kinetics and byproducts identification of the Aflatoxin B1 in aqueous medium by ultra‐performance liquid chromatography–quadrupole time‐of‐flight mass spectrometry
Authors: Liu Ruijie , Jin Qingzhe , Tao Guanjun , Shan Liang , Huang Jianhua , Liu Yuanfa , Wang Xingguo , Mao Wenyue , Wang Shanshan 
Published: April 2010

AbstractA photodegradation study of Aflatoxin B1 (AFB1) in water solution was performed under UV irradiation at different AFB1 initial concentrations and UV irradiation intensities. The effect of UV intensity on the AFB1 photodegradation ratio is dominative, when compared with AFB1 initial concentration. The photodegradation of AFB1 was proved to follow first‐order reaction kinetics (R2 ≥ 0.99). Three photodegradation products, i.e. P1 (C17H14O7), P2 (C16H14O6) and P3 (C16H12O7), were identified on the basis of low mass error and high matching property by ultra‐performance liquid chromatography–quadrupole time‐of‐flight mass spectrometry (UPLC–Q‐TOF MS), and the degradation pathway was proposed. This study first reports the appearance of these photodegradation products and the proposed degradation pathway in aqueous media. Copyright © 2010 John Wiley & Sons, Ltd.
Long‐lasting post‐mortem activity of spinal microglia in situ in mice
Authors: Dibaj Payam , Steffens Heinz , Nadrigny Fabien , Neusch Clemens , Kirchhoff Frank , Schomburg Eike D. 
Published: April 2010

AbstractAs CNS macrophages, microglia show a high spontaneous motility of their processes, continuously surveying their microenvironment. Upon CNS injury, microglia react by immediate cellular polarization and process extension toward the lesion site as well as by subsequent amoeboid lesion‐directed migration and phagocytosis. To determine the ability of microglia to fulfill their role within distinctively lesioned tissue in the absence of life support, we investigated microglial activity and responsiveness to laser‐induced axonal injuries in the spinal dorsal columns in situ after cardiac and respiratory arrest, i.e., post‐mortem, in the progressively degrading nervous tissue. For this purpose, we used time‐lapse two‐photon laser scanning microscopy in double transgenic mice expressing enhanced green fluorescent protein in microglia and enhanced yellow fluorescent protein in projection neurons. Depending on the premortal condition of the animal, microglial activity and responsiveness remain for up to5–10 hr post‐mortem. Thereby, the continuously decreasing glial reaction is independent of oxygen and glucose supply but requires residual ATP, suggesting a parasitic form of energy, such as a transmembrane uptake of ATP released from injured nervous tissue. Even though initially microglia are able to detect axonal injury after disruption of the blood supply, the later aspects of glial reaction, for example amoeboid conversion and migration, are absent post‐ mortem, corresponding to the failure of microglia to prevent secondary damage after injury of nervous tissue. © 2010 Wiley‐Liss, Inc.
Chronic social isolation suppresses proplastic response and promotes proapoptotic signalling in prefrontal cortex of Wistar rats
Authors: Djordjevic Ana , Adzic Miroslav , Djordjevic Jelena , Radojcic Marija B. 
Published: April 2010

AbstractSuccessful adaptation to stress involves synergized actions of glucocorticoids and catecholamines at several levels of the CNS, including the prefrontal cortex (PFC). Inside the PFC, hormonal signals trigger concerted actions of transcriptional factors, such as glucocorticoid receptor (GR) and nuclear factor kappa B (NFκB), culminating in a balanced, proadaptive expression of their common genes, such as proplastic NCAM and/or apoptotic Bax and Bcl‐2. In the present study, we hypothesized that chronic stress may compromise the balance between GR and NFκB signals and lead to an altered/maladaptive expression of their cognate genes in the PFC. Our results obtained with Wistar rats exposed to chronic social isolation indicated alterations of the GR relative to the NFκB, in favor of the GR, in both the cytoplasmic and the nuclear compartments of the PFC. Although these alterations did not affect the induction of proplastic NCAM gene, they decreased the NCAM sialylation necessary for plastic response and caused marked relocation of the mitochondrial membrane antiapoptotic Bcl‐2 protein to its cytoplasmic form. Moreover, the compromised PSA‐NCAM plastic response found under chronic stress was sustained after exposure of animals to the subsequent acute stress, whereas the proapoptotic signals were further emphasized. It is concluded that chronic social isolation of Wistar animals leads to a maladaptive response of the PFC, considering the diminishment of its plastic potential and potentiating of apoptosis. Such conditions in the PFC are likely to compromise its ability to interact with other CNS structures, such as the hippocampus, which is necessary for successful adaptation to stress. © 2010 Wiley‐Liss, Inc.
Peptidylgycine α‐amidating monooxygenase and copper: A gene–nutrient interaction critical to nervous system function
Authors: Bousquet‐Moore Danielle , Mains Richard E. , Eipper Betty A. 
Published: April 2010

AbstractPeptidylgycine α‐amidating monooxygenase (PAM), a highly conserved copper‐dependent enzyme, is essential for the synthesis of all amidated neuropeptides. Biophysical studies revealed that the binding of copper to PAM affects its structure, and cell biological studies demonstrated that the endocytic trafficking of PAM was sensitive to copper. We review data indicating that genetic reduction of PAM expression and mild copper deficiency in mice cause similar alterations in several physiological functions known to be regulated by neuropeptides: thermal regulation, seizure sensitivity, and anxiety‐like behavior. © 2010 Wiley‐Liss, Inc.
An integer decomposition algorithm for solving a two‐stage facility location problem with second‐stage activation costs
Authors: Penuel John , Smith J. Cole , Yuan Yang 
Published: April 2010

AbstractWe study a stochastic scenario‐based facility location problem arising in situations when facilities must first be located, then activated in a particular scenario before they can be used to satisfy scenario demands. Unlike typical facility location problems, fixed charges arise in the initial location of the facilities, and then in the activation of located facilities. The first‐stage variables in our problem are the traditional binary facility‐location variables, whereas the second‐stage variables involve a mix of binary facility‐activation variables and continuous flow variables. Benders decomposition is not applicable for these problems due to the presence of the second‐stage integer activation variables. Instead, we derive cutting planes tailored to the problem under investigation from recourse solution data. These cutting planes are derived by solving a series of specialized shortest path problems based on a modified residual graph from the recourse solution, and are tighter than the general cuts established by Laporte and Louveaux for two‐stage binary programming problems. We demonstrate the computational efficacy of our approach on a variety of randomly generated test problems. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Path optimization for the resource‐constrained searcher
Authors: Sato Hiroyuki , Royset Johannes O. 
Published: April 2010

AbstractWe formulate and solve a discrete‐time path‐optimization problem where a single searcher, operating in a discretized three‐dimensional airspace, looks for a moving target in a finite set of cells. The searcher is constrained by maximum limits on the consumption of one or more resources such as time, fuel, and risk along any path. We develop a specialized branch‐and‐bound algorithm for this problem that uses several network reduction procedures as well as a new bounding technique based on Lagrangian relaxation and network expansion. The resulting algorithm outperforms a state‐of‐the‐art algorithm for solving time‐constrained problems and also is the first algorithm to solve multi‐constrained problems. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010
Improvement of PUFEM for the numerical solution of high‐frequency elastic wave scattering on unstructured triangular mesh grids
Authors: El Kacimi A. , Laghrouche O. 
Published: April 2010

AbstractThe purpose of this paper, which builds on previous work (Int. J. Numer. Meth. Engng 2009; 77:1646–1669), is to improve a numerical scheme based on the partition of unity finite element method (PUFEM) for the solution of the time harmonic elastic wave equations. The approach consists to approximate the displacement field by the standard finite element shape functions, enriched locally by superimposing pressure (P) and shear (S) plane waves. The aim is to accurately model two‐dimensional elastic wave problems on relatively coarse mesh grids, capable of containing many wavelengths per nodal spacing, for wide ranges of frequencies. This allows us to relax the traditional requirement of about 10 nodal points per S wavelength. In this work, an exact integration scheme for the linear triangular finite element is developed to evaluate the oscillatory integrals arising from the use of the PUFEM. The main contribution here consists in developing an explicit closed‐form solution for two‐dimensional wave‐based integrals, when the phase variation is linear in the local coordinate element system. The evaluation of the element mass matrix is performed from appropriate edge integrals. All other element matrices, obtained by adequate splitting of the element stress tensor matrix, are simply deduced from the element mass matrix entries.The results show clearly that the proposed integration scheme evaluates accurately the entries of the global matrix with drastic reduction of the computational time. Numerical tests dealing with the scattering of S elastic plane waves by a circular rigid body show that, for the same discretization level, it is possible to improve the accuracy by using large elements associated with high numbers of approximating plane waves rather than using small elements with less plane waves. However, this increases the conditioning and the fill‐in of the global matrix. At high frequency, it is even possible to push the number of degrees of freedom per S wavelength under 2 and still achieve good accuracy. Finally, some remarks on the choice of the numbers of P and S plane waves leading to better accuracy and conditioning are discussed. Copyright © 2010 John Wiley & Sons, Ltd.
A modified version of a T‐Cell Algorithm for constrained optimization problems
Authors: Aragón Victoria S. , Esquivel Susana C. , Coello Carlos A. Coello 
Published: April 2010

AbstractIn this paper, we present a heuristic inspired on the T‐Cell model of the immune system (i.e. an artificial immune system). The proposed approach (called T‐Cell) is used for solving constrained (numerical) optimization problems, and is validated using several test functions taken from the specialized literature on evolutionary optimization. Additionally, several engineering optimization problems are also used for assessing the performance of the proposed approach. The results are compared with respect to approaches representative of the state‐of‐the‐art in constrained evolutionary optimization. Copyright © 2010 John Wiley & Sons, Ltd.
Nuclear β‐catenin expression and Wnt signalling: in defence of the dogma
Authors: Fodde Riccardo , Tomlinson Ian 
Published: April 2010

AbstractInactivation of the APC tumour suppressor gene represents the rate‐limiting event in colorectal cancer. Loss of APC function leads to constitutive activation of the canonical Wnt–β‐catenin signalling pathway, thus resulting into a broad spectrum of cellular defects, ranging from stem cell self‐renewal and differentiation, apoptosis, migration and proliferation. Recently, Phelps et al 1 presented an alternative model where loss of APC does not primarily result in Wnt signalling activation but rather involves the transcriptional co‐repressor CtBP1. According to this alternative scenario, oncogenic KRAS activation represents a conditio sine qua non for nuclear β‐catenin translocation and Wnt activation. In a recent issue of the Journal of Pathology, Obrador‐Hevia and collaborators 2 reaffirmed the broadly accepted textbook model by showing the presence of nuclear β‐catenin in both the presence and, more often, the absence of KRAS mutations. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Influence of racemization on stereocomplex‐induced gelation of water‐soluble polylactide–poly(ethylene glycol) block copolymers
Authors: Nouailhas Helene , Li Feng , El Ghzaoui Abdelsalm , Li Suming , Coudane Jean 
Published: April 2010

AbstractRing‐opening polymerization of L‐ or D‐lactide was realized at 140 °C for a period of 7 days in the presence of dihydroxyl poly(ethylene glycol) (PEG), with M̄n = 4000 g mol−1, using zinc lactate as initiator. The resulting poly(L‐lactide)–PEG–poly(L‐lactide) and poly(D‐lactide)–PEG–poly(D‐lactide) triblock copolymers are water soluble with polylactide (PLA) block length ranging from 11 to 17 units. Both the tube inverting method and rheological measurements were used to evaluate the gelation properties of aqueous solutions containing single copolymers or L/D copolymer pairs. Stereocomplexation between poly(L‐lactide) and poly(D‐lactide) blocks is observed for mixed solutions. Hydrogel formation is detected in the case of relatively long PLA blocks (DPPLA = 17), but not for copolymers with shorter PLA blocks (DPPLA = 11–13) due to partial racemization of L‐lactyl units. Racemization is largely reduced when the reaction time is shortened to 1 day. Under these conditions, DPPLA of 8 is sufficient for the stereocomplexation of PLA–PEG block copolymers, and DPPLA above 10 leads to the formation of hydrogels of PLA–PEG block copolymers. On the other hand, racemization appears as a general phenomenon in the (co)polymerization of L‐lactide with Zn(Lac)2 as initiator, although it is negligible or undetectable in the case of high molar mass polymers. Therefore, racemization is the limiting factor for the stereocomplexation‐induced gelation of water‐soluble PLA–PEG block copolymers where the PLA block length generally ranges from 10 to 30. Reaction conditions including initiator, time and temperature should be strictly controlled to minimize racemization. Copyright © 2010 Society of Chemical Industry