bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bedform response to flow variability
Authors: Nelson J. M. , Logan B. L. , Kinzel P. J. , Shimizu Y. , Giri S. , Shreve R. L. , McLean S. R. 
Published: July 2011

ABSTRACTLaboratory observations and computational results for the response of bedform fields to rapid variations in discharge are compared and discussed. The simple case considered here begins with a relatively low discharge over a flat bed on which bedforms are initiated, followed by a short high‐flow period with double the original discharge, during which the morphology of the bedforms adjusts, followed in turn by a relatively long period of the original low discharge. For the grain size and hydraulic conditions selected, the Froude number remains subcritical during the experiment, and sediment moves predominantly as bedload. Observations show rapid development of quasi‐two‐dimensional bedforms during the initial period of low flow with increasing wavelength and height over the initial low‐flow period. When the flow increases, the bedforms rapidly increase in wavelength and height, as expected from other empirical results. When the flow decreases back to the original discharge, the height of the bedforms quickly decreases in response, but the wavelength decreases much more slowly. Computational results using an unsteady two‐dimensional flow model coupled to a disequilibrium bedload transport model for the same conditions simulate the formation and initial growth of the bedforms fairly accurately and also predict an increase in dimensions during the high‐flow period. However, the computational model predicts a much slower rate of wavelength increase, and also performs less accurately during the final low‐flow period, where the wavelength remains essentially constant, rather than decreasing. In addition, the numerical results show less variability in bedform wavelength and height than the measured values; the bedform shape is also somewhat different. Based on observations, these discrepancies may result from the simplified model for sediment particle step lengths used in the computational approach. Experiments show that the particle step length varies spatially and temporally over the bedforms during the evolution process. Assuming a constant value for the step length neglects the role of flow alterations in the bedload sediment‐transport process, which appears to result in predicted bedform wavelength changes smaller than those observed. However, observations also suggest that three‐dimensional effects play at least some role in the decrease of bedform wavelength, so incorporating better models for particle hop lengths alone may not be sufficient to improve model predictions. Published in 2011. This article is a US Government work and is in the public domain in the USA.
Isolation and characterization of an environmental cadmium- and tellurite-resistant Pseudomonas strain
Authors: Chien Chih-Ching , Jiang Ming-Hui , Tsai Meng-Ru , Chien Chih-Ching 
Published: July 2011

Abstract
A Pseudomonas strain (TeU), resistant to tellurite (TeO 32−) and cadmium (Cd2+) ions, was isolated from heavy-metal–contaminated sediments by enrichment. Black precipitates, presumably the product of the reduction of tellurite, such as tellurium, occurred in cultures of the isolate after growth in medium containing tellurite. Quantitative determination of the TeO 32− concentration in the liquid culture demonstrated a decreased concentration of tellurite (to less than 100 µM) from initial concentrations of approximately 1,000 µM within 24 h of growth. Strain TeU was resistant to TeO 32− and Cd2+ concentrations as high as 2,000 µM and 500 µM, respectively. Transposon mutagenesis of strain TeU resulted in mutants exhibiting Cd2+ sensitivity (Strain BU21) and one with decreased ability to reduce tellurite (strain AU08). Strain BU21 was less tolerant to Cd2+ (100 µM) compared with the wild-type strain TeU (500 µM) but was still able to reduce tellurite to 80% of that of strain TeU. Although strain AU08 possesses the ability for Cd2+ resistance, it reduced less than 20% of the initial concentrations of tellurite compared with strain TeU. Genes encoding an HflKC complex and a putative metallopeptidase were associated with the bacterium's capacity for tellurite reduction and Cd resistance, respectively. The ability to reduce tellurite therefore may not be necessary for this bacterium's heavy metal and metalloid tellurite resisting ability. Environ. Toxicol. Chem. 2011;30:2202–2207. © 2011 SETAC
Vapor pressure of solid polybrominated diphenyl ethers determined via Knudsen effusion method
Authors: Fu Jinxia , Suuberg Eric M 
Published: July 2011

Abstract
Polybrominated diphenyl ethers (PBDEs) are flame retardants used in a variety of consumer products. The solid vapor pressures of BDE 15 and BDE 209 were determined by using the Knudsen effusion method, and the values measured extrapolated to 298.15 K are 3.12 × 10−3 and 9.02 × 10−13 Pa, respectively. The enthalpies of sublimation for these compounds have also been estimated by using the Clausius-Clapeyron equation and are 102.0 ± 3.5 and 157.1 ± 3.5 kJ/mol, respectively. In addition, the melting points and enthalpies of fusion were measured by differential scanning calorimetry. Environ. Toxicol. Chem. 2011;30:2216–2219. © 2011 SETAC
Provably stable and time‐accurate extensions of Runge–Kutta schemes for CFD computations on moving grids
Authors: Brogniez Sebastien , Rajasekharan Ajaykumar , Farhat Charbel 
Published: July 2011

SUMMARYExtending fixed‐grid time integration schemes for unsteady CFD applications to moving grids, while formally preserving their numerical stability and time accuracy properties, is a nontrivial task. A general computational framework for constructing stability‐preserving ALE extensions of Eulerian multistep time integration schemes can be found in the literature. A complementary framework for designing accuracy‐preserving ALE extensions of such schemes is also available. However, the application of neither of these two computational frameworks to a multistage method such as a Runge–Kutta (RK) scheme is straightforward. Yet, the RK methods are an important family of explicit and implicit schemes for the approximation of solutions of ordinary differential equations in general and a popular one in CFD applications. This paper presents a methodology for filling this gap. It also applies it to the design of ALE extensions of fixed‐grid explicit and implicit second‐order time‐accurate RK (RK2) methods. To this end, it presents the discrete geometric conservation law associated with ALE RK2 schemes and a method for enforcing it. It also proves, in the context of the nonlinear scalar conservation law, that satisfying this discrete geometric conservation law is a necessary and sufficient condition for a proposed ALE extension of an RK2 scheme to preserve on moving grids the nonlinear stability properties of its fixed‐grid counterpart. All theoretical findings reported in this paper are illustrated with the ALE solution of inviscid and viscous unsteady, nonlinear flow problems associated with vibrations of the AGARD Wing 445.6. Copyright © 2011 John Wiley & Sons, Ltd.
A monotone finite volume scheme for advection–diffusion equations on distorted meshes
Authors: Wang Shuai , Yuan Guangwei , Li Yonghai , Sheng Zhiqiang 
Published: July 2011

SUMMARYA new monotone finite volume method with second‐order accuracy is presented for the steady‐state advection–diffusion equation. The method uses a nonlinear approximation for both diffusive and advective fluxes that guarantee the positivity of the numerical solution. The approximation of the diffusive flux is based on nonlinear two‐point approximation, and the approximation of the advective flux is based on the second‐order upwind method with proper slope limiter. The second‐order convergence rate for concentration and the monotonicity of the nonlinear finite volume method are verified with numerical experiments. Copyright © 2011 John Wiley & Sons, Ltd.
Large eddy simulation using a dynamic mixing length subgrid‐scale model
Authors: Zhaolin Gu , Jianying Jiao , Yunwei Zhang , Junwei Su 
Published: July 2011

SUMMARYA novel dynamic mixing length (DML) subgrid‐scale model for large eddy simulations is proposed in this work to improve the cutoff length of the Smagorinsky model. The characteristic mixing length (or the characteristic wave number) is dynamically estimated for the subgrid‐scale fluctuation of turbulence by the cutoff wave‐number, kc, and the dissipation wave‐number, kd. The dissipation wave number is derived from the kinetic energy spectrum equation and the dissipation spectrum equation. To prove the promise of the DML model, this model is used to simulate the lid‐driven cubical cavity with max‐velocity‐based Reynolds numbers 8850 and 12,000, the channel flows with friction‐velocity‐based Reynolds numbers 180, 395, 590, and 950, and the turbulent flow past a square cylinder at the higher Reynolds number 21,400, respectively, compared with the Smagorinsky model and Germano et al.'s dynamic Smagorinsky model. Different numerical experiments with different Reynolds numbers show that the DML model can be used in simulations of flows with a wide range of Reynolds numbers without the occurrence of singular values. The DML model can alleviate the dissipation of the Smagorinsky model without the loss of its robustness. The DML model shows some advantages over Germano et al.'s dynamic Smagorinsky model in its high stability and simplicity of calculation because the coefficient of the DML model always stays positive. The characteristic mixing length in the DML model reflects the subgrid‐scale fluctuation of turbulence in nature and thus the characteristic mixing length has a spatial and temporal distribution in turbulent flow. Copyright © 2011 John Wiley & Sons, Ltd.
Electrowetting of Molten Carbonate Electrolytes
Authors: Hsieh P. H. , Selman J. R. 
Published: July 2011

AbstractThe wetting characteristics of various molten carbonate electrolytes were experimentally measured and the dependence of the contact angle on polarisation was thoroughly examined for various temperatures and gas atmospheres. At open circuit under an atmosphere of CO2 and/or oxidant gases, addition of alkaline earth carbonates decreases the wettability of the electrolyte. Addition of alkaline earth carbonates also tends to decrease the temperature dependence of the contact angle. Upon polarisation, the contact angle shows a complex behaviour. In an oxidising atmosphere its dependence on potential is roughly symmetric (like an electrocapillary curve) but in a reducing atmosphere this is not the case. Generally, the contact angle increases upon cathodic polarisation but decreases in the anodic direction. These changes in contact angle are interpreted in terms of interfacial tensions. The complex dependence of contact angle on polarisation can be interpreted in terms of a superimposed electrocapillary and transport effects. As such, it may be affected by specifically adsorbed species at the electrode surface (especially complex oxides), by the basicity (oxide ion activity) of the melt, and by the potential‐induced segregation of the cationic species in the carbonate melt.
Chiral Cooperativity in Helical Polymers
Authors: Jain Vipul , Cheon Kap‐Soo , Tang Kai , Jha Salil , Green Mark M. 
Published: July 2011

AbstractHuman experience informs us of the two extreme consequences of crowding: random behavior of the individuals, in which each takes a singular path; and cooperative behavior, in which the individuals in the crowd act in a predictable uniform manner, such as in a military organization These extremes find parallels in the crowded situations encountered at the molecular level, exemplified for the former by glassy states, such as often encountered in polymeric materials,1 or for the latter, in the uniform archetypal arrangements of crystals or liquid crystals. Here we review the cooperative characteristics of uniform arrangements that take a chiral form and explore how these characteristics lead to left‐ and right‐handedness. These studies lead us to understand the basis of amplification of chirality in regular arrays, in which small influences have large consequences, and how chiral cooperativity acts in the resolution of conflict between influences favoring left‐ and right‐handedness.2
Supramolecular Capsules Derived from Calixpyrrole Scaffolds
Authors: Ballester Pablo 
Published: July 2011

AbstractThis review article describes recent results obtained in the self‐assembly of supramolecular capsules derived from calixpyrrole components. Due to their ease of synthesis, calix[4]pyrroles are by far the most typically used units in these systems. A clear conformational and structural analogy exists between calix[4]arenes and calix[4]pyrroles. However, to date, the number of examples in the literature that use calix[4]pyrrole scaffolds instead of calix[4]arenes for the construction of supramolecular capsules is still meager. Four different approaches are considered for the use of calix[4]pyrrole derivatives in the assembly of molecular capsules. Firstly, in an analogous manner to resorcin[4]arenes and pyrogallol[4]arenes, aryl‐extended calix[4]pyrroles with hydroxyl groups in their upper rim self‐assemble through direct or mediated rim‐to‐rim interactions into capsular aggregates. Secondly, aryl‐extended calix[4]pyrroles having non‐complementary hydrogen‐bonding groups in their upper rim form dimeric templated capsules with suitable substrates. Thirdly, the elaboration of the upper rim of the calix[4]pyrroles with urea groups affords dimeric capsules with polar functionalized interiors that closely resemble their tetraurea calix[4]arene analogs. Finally, the chemical modification of the pyrrole units of octamethyl calix[4]pyrrole into tetrathiafulvalene derivatives yields dimeric capsules induced by anion coordination that display interesting properties in the binding of electron‐poor guests.
Vascular targeting of antithrombotic agents
Authors: Carnemolla Ronald , Muzykantov Vladimir R. 
Published: July 2011

AbstractIn this review we discuss the limited efficacy for current pharmacological agents used in prophylaxis and treatment of thrombosis and highlight targeted delivery of anti‐thrombotic agents to fibrin, platelets, red blood cells and endothelium. © 2011 IUBMB IUBMB Life, 2011
Targeted siRNA delivery to diseased microvascular endothelial cells—Cellular and molecular concepts
Authors: Kowalski Piotr S. , Leus Niek G. J. , Scherphof Gerrit L. , Ruiters Marcel H. J. , Kamps Jan A. A. M. , Molema Grietje 
Published: July 2011

AbstractIncreased insight in the role of endothelial cells in the pathophysiology of cancer, inflammatory and cardiovascular diseases, has drawn great interest in pharmacological interventions aiming at the endothelium in diseased sites. Their location in the body makes them suitable targets for therapeutic approaches based on targeted drug delivery. Functional heterogeneity of the microvascular bed in normal organ homeostasis has been appreciated for a long time, and more recent studies have revealed heterogeneity in endothelial reactivity to inflammatory stimuli as well. Upon stimulation, each organ displays a vascular bed specific pattern of cell adhesion molecules providing challenging opportunities to deliver drugs or small RNAs to organ specific (micro)vascular endothelial subsets. In this review we introduce general concepts of endothelial heterogeneity in relation to disease state and its consequences for targeted therapeutic interventions. Furthermore, we will describe novel approaches to interfere with endothelial cell engagement in disease with a main focus on siRNA therapeutics and currently used nonviral lipid and polymer‐based siRNA delivery systems. The last part of this review addresses some technical issues that are essential in proving the concept of target mRNA knock down in a vascular bed specific manner, and the further development of effective endothelial cell specific drug delivery devices. © 2011 IUBMB IUBMB Life, 2011
Innovation and competition: An unstable relationship
Authors: Correa Juan A. 
Published: July 2011

SUMMARYThis paper analyzes how the establishment of the United States Court of Appeals for the Federal Circuit in 1982 has affected the relationship between innovation and competition. Using the same dataset as Aghion et al. (Competition and innovation: an inverted‐u relationship. Quarterly Journal of Economics 2005; 120(2):701–728) I find a structural break in the early 1980s. Taking this break into consideration, the inverted‐U empirical relationship between innovation and competition found by Aghion et al. does not hold. In fact, I find that there is a positive innovation–competition relationship during the period 1973–1982 and no relationship at all in the 1983–1994 period. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of SiO2 nanoparticles on HFL‐I activating ROS‐mediated apoptosis via p53 pathway
Authors: Xu Zhengli , Chou Laisheng , Sun Jiao 
Published: July 2011

ABSTRACTSilicon dioxide nanoparticles (SiO2 NPs) have attracted increasing interest as nanovehicles for delivering drugs, genes and bio‐active molecules into cells. However, it is still unknown whether SiO2 NPs could cause side‐effects to normal cells. In the present study, human lung fibroblasts (HFL‐Is) were directly exposed to two different sizes of SiO2 NPs. The effect of size and concentration on cell response was studied by analyzing the cell viability, the ratio of apoptosis and the pathway of cell injury. The results demonstrated that a size‐associated and a dose‐dependent toxicity of HFL‐Is was induced by SiO2 NPs. Meanwhile, the expression of reactive oxygen species in HFL‐I was significantly increased. This activation effect was accompanied by upregulation of p53 expression, release of cytochrome C from chondriosomes, inhibition of Bcl2, and activation of Bax and caspase 9. These findings implied that SiO2 NPs might induce apoptosis of HFL‐Is by stimulating reactive oxygen species release and subsequently causing the activation of p53 pathway in vitro. Copyright © 2011 John Wiley & Sons, Ltd.
A simple cryo‐holder facilitates specimen observation under a conventional scanning electron microscope
Authors: Tang Chih‐Yuan , Huang Rong‐Nan , Kuo‐Huang Ling‐Long , Kuo Tai‐Chih , Yang Ya‐Yun , Lin Ching‐Yeh , Jane Wann‐Neng , Chen Shiang‐Jiuun 
Published: July 2011

AbstractA pre‐cryogenic holder (cryo‐holder) facilitating cryo‐specimen observation under a conventional scanning electron microscope (SEM) is described. This cryo‐holder includes a specimen‐holding unit (the stub) and a cryogenic energy‐storing unit (a composite of three cylinders assembled with a screw). After cooling, the cryo‐holder can continue supplying cryogenic energy to extend the observation time for the specimen in a conventional SEM. Moreover, the cryogenic energy‐storing unit could retain appropriate liquid nitrogen that can evaporate to prevent frost deposition on the surface of the specimen. This device is proved feasible for various tissues and cells, and can be applied to the fields of both biology and material science. We have employed this novel cryo‐holder for observation of yeast cells, trichome, and epidermal cells in the leaf of Arabidopsis thaliana, compound eyes of insects, red blood cells, filiform papillae on the surface of rat tongue, agar medium, water molecules, penicillium, etc. All results suggested that the newly designed cryo‐holder is applicable for cryo‐specimen observation under a conventional SEM without cooling system. Most importantly, the design of this cryo‐holder is simple and easy to operate and could adapt a conventional SEM to a plain type cryo‐SEM affordable for most laboratories. Microsc. Res. Tech., 2011. © 2011 Wiley Periodicals, Inc.
In‐situ observation and relocation method of nanomaterial samples based on microscope systems
Authors: Zeng Leyong , Wu Aiguo , Wang Yazhuo , Pu Shiliu , Ding Jiandong 
Published: July 2011

AbstractTaking poly(lactic acid) microbubbles and purple membranes as examples, a general in situ observation and relocation method of nanomaterial samples based on microscope systems was reported. First, a four‐grade coordinate with different precisions was marked around a substrate by UV lithography. Second, using optical microscope and scanning probe microscope, special positions of poly(lactic acid) microbubbles and purple membranes were observed, respectively. Third, the four‐grade coordinate value corresponded to the special sample position, and the distance between the special position and coordinate edge were recorded, respectively. Finally, the special position can be easily found again, or the sample in the special position can be manipulated and secondary processed based on the recorded coordinate value and distance, after the sample was removed and then was reset on the sample stage of microscope. The in situ observation and relocation method can be applied in different microscope systems and different sample substrates, and will have potential applications in the manipulation and the secondary process of micro‐ and nano‐devices. Microsc. Res. Tech., 2011. © 2011 Wiley Periodicals, Inc.
Role of parietal and principal gastric mucosa cells in the phenomenon of concentration of aluminum and indium
Authors: Maghraoui Samira , Ayadi Ahlem , Audinot Jean‐Nicolas , Ammar Aouatef Ben , Jaafoura Mohamed‐Habib , Hili Ali El , Migeon Henri‐Noël , Tekaya Leila 
Published: July 2011

AbstractThe subcellular behavior of aluminum and indium, used in medical and industrial fields, was studied in the gastric mucosa and the liver after their intragastric administration to rats, using, two of the most sensitive methods of observation and microanalysis, the transmission electron microscopy, and the secondary ion mass spectrometry. The ultrastructural study showed the presence of electron dense deposits, in the lysosomes of parietal and principal gastric mucosa cells but no loaded lysosomes were observed in the different studied hepatic territories. The microanalytical study allowed the identification of the chemical species present in those deposits as aluminum or indium isotopes and the cartography of their distribution. No modification was observed in control rats tissues. In comparison to previous studies describing the mechanism of aluminum concentration in the gastric mucosa and showing that this element was concentrated in the lysosomes of fundic and antral human gastric mucosa, our study provided additional informations about the types of cells involved in the phenomenon of concentration of aluminum and indium, which are the parietal and the principal cells of the gastric mucosa. Our study demonstrated that these cells have the ability to concentrate selectively aluminum and indium in their lysosomes, as a defensive reaction against intoxication by foreign elements. Microsc. Res. Tech., 2011 © 2011 Wiley Periodicals, Inc.