bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration of nanoporous membranes for sample filtration/preconcentration in microchip electrophoresis
Authors: Long Zhicheng , Liu Dayu , Ye Nannan , Qin Jianhua , Lin Bingcheng 
Published: November 2006

AbstractMicrofluidic devices integrating membrane‐based sample preparation with electrophoretic separation are demonstrated. These multilayer devices consist of 10 nm pore diameter membranes sandwiched between two layers of PDMS substrates with embedded microchannels. Because of the membrane isolation, material exchange between two fluidic layers can be precisely controlled by applied voltages. More importantly, since only small molecules can pass through the nanopores, the integrated membrane can serve as a filter or a concentrator prior to microchip electrophoresis under different design and operation modes. As a filter, they can be used for separation and selective injection of small analytes from sample matrix. This has been effectively applied in rapid determination of reduced glutathione in human plasma and red blood cells without any off‐chip deproteinization procedure. Alternatively, in the concentrator mode, they can be used for online purification and preconcentration of macromolecules, which was illustrated by removing primers and preconcentrating the product DNA from a PCR product mixture.
The origin, typology, spatial distribution and detrimental effects of the sinkholes developed in the alluvial evaporite karst of the Ebro River valley downstream of Zaragoza city (NE Spain)
Authors: Gutiérrez F. , Galve J.P. , Guerrero J. , Lucha P. , Cendrero A. , Remondo J. , Bonachea J. , Gutiérrez M. , Sánchez J.A. 
Published: November 2006

AbstractThree types of sinkhole have been mapped in a 50 km2 stretch of the Ebro River valley downstream of Zaragoza: large collapse sinkholes, large shallow subsidence depressions and small cover‐collapse sinkholes. The sinkholes relate to the karstification of evaporitic bedrock that wedges out abruptly downstream, giving way to a shale substratum. Twenty‐three collapse sinkholes, up to 50 m in diameter by 6 m deep, and commonly hosting saline ponds, have been identified in the floodplain. They have been attributed to the upward stoping of dissolutional cavities formed within the evaporitic bedrock by rising groundwater flows. Twenty‐four large shallow subsidence depressions were mapped in the floodplain. These may reach 850 m in length and were formed by structurally controlled interstratal karstification of soluble beds (halite or glauberite? and gypsum) by rising groundwater flow and the progressive settlement of the overlying bedrock and overburden sediments. A total of 447 small cover‐collapse, or dropout, sinkholes have been recognized in a perched alluvial level along the southern margin of the valley. These sinkholes result from the upward propagation of voids through the alluvial mantle caused by the downward migration of detrital sediments into dissolutional voids. The majority of these sinkholes, commonly 1·5–2 m in diameter, are induced by human activities. Over the karstic bedrock, there is a significant increase in sinkhole density downstream. This is interpreted as being a result of the evaporitic bedrock wedging out and the convergence of the groundwater flow lines in the karstic aquifer. The collapse sinkholes in this area, locally with a probability of occurrence higher than 140 sinkholes/km2/year, cause substantial damage to the linear infrastructures, buildings and agriculture, and they might eventually cause the loss of human lives. Copyright © 2006 John Wiley & Sons, Ltd.
Contemporary versus long‐term denudation along a passive plate margin: the role of extreme events
Authors: Tomkins K. M. , Humphreys G. S. , Wilkinson M. T. , Fink D. , Hesse P. P. , Doerr S. H. , Shakesby R. A. , Wallbrink P. J. , Blake W. H. 
Published: November 2006

AbstractShort‐term (contemporary) and long‐term denudation rates were determined for the Blue Mountains Plateau in the western Sydney Basin, Australia, to explore the role of extreme events (wildfires and catastrophic floods) in landscape denudation along a passive plate margin. Contemporary denudation rates were reconstructed using 40 years of river sediment load data from the Nattai catchment in the south‐west of the basin, combined with an analysis of hillslope erosion following recent wildfires. Long‐term denudation rates (10 kyr–10 Myr) were determined from terrestrial cosmogenic nuclides, apatite fission track thermochronology and post‐basalt flow valley incision. Contemporary denudation rates average several times lower than the long‐term average (5·5 ± 4 mm kyr−1 versus 21·5 ± 7 mm kyr−1). Erosion of sediment following wildfires accounts for only a small proportion (5%) of the contemporary rate. Most post‐fire sediment is stored on the lower slopes and valley floor, with the amount transported to the river network dependent on rainfall–run‐off conditions within the first few years following the fire. Historical catastrophic floods account for a much larger proportion (35%) of the contemporary erosion rate, and highlight the importance of these events in reworking stored material. Evidence for palaeofloods much larger than those experienced over the past 200 years suggests even greater sediment export potential. Mass movement on hillslopes along valleys incised into softer lithology appears to be a dominant erosion process that supplies substantial volumes of material to the valley floor. It is possible that a combination of infrequent mass movement events and high fluvial discharge could account for a significant proportion of the discrepancy between the contemporary and long‐term denudation rates. Copyright © 2006 John Wiley & Sons, Ltd.
Direct 2D simulation of small gas bubble clusters: from the expansion step to the equilibrium state
Authors: Bruchon J. , Fortin A. , Bousmina M. , Benmoussa K. 
Published: November 2006

AbstractA numerical strategy, based on an adaptive finite element method, is proposed for the direct two‐dimensional simulation of the expansion of small clusters of gas bubbles within a Newtonian liquid matrix. The velocity and pressure fields in the liquid are first defined through the Stokes equations and are subsequently extended to the gas bubbles. The liquid–gas coupling is imposed through the stress exerted on the liquid by gas pressure (ruled by an ideal gas law) and by surface tension. A level set method, combined with a mesh adaptation technique, is used to track liquid–gas interfaces. Many numerical simulations are presented. The single bubble case allows to compare the simulations to an analytical model. Simulations of the expansion of small clusters are then presented showing the interaction and evolution of the gas bubbles to an equilibrium state, involving topological rearrangements induced by Plateau's rule. Copyright © 2006 John Wiley & Sons, Ltd.
Aerosols dispersion modelling using probabilistic particle tracking
Authors: Smirnov Andrei , Rowan Steven , McCormick James 
Published: November 2006

AbstractA method is proposed which can facilitate parallel computations of particle transport in complex environments, such as urban landscapes. A two stage‐approach is used, where in the first stage, physical simulations of various aerosol release scenarios are conducted on a high‐performance distributed computing facility, such as a Beowulf cluster or a computing grid, and stored in a database as a set of transfer probabilities. In this stage, the method provides a partially decoupled parallel implementation of a tightly coupled physical system. In the second stage, various aerosol release scenarios can be analysed in a timely manner, using obtained probability distributions and a simpler stochastic simulator, which can be executed on a commodity computer, such as a workstation or a laptop. The method presents a possibility of solving the inverse problem of determining the release source from the available deposition data. Using the proposed approach and developed graphical tools, a case of aerosol dispersion in a typical urban landscape has been studied. A considerable speedup of analysis time for different aerosol dispersion scenarios has been demonstrated. The method is appropriate for the development of express risk analysis systems. Copyright © 2006 John Wiley & Sons, Ltd.
Cytotoxicity of partial‐stabilized cement
Authors: Wang Wen‐Hsi , Lin Feng‐Huei , Lee Yuan‐Ling , Lin Chun‐Pin 
Published: November 2006

AbstractPartial‐stabilized cement (PSC) is a kind of modified calcium silicate cement used for root‐end surgery. Minor transition metal elements Co, Cr, and Zn were added for enhancing the setting property of to PSC. In our previous study, minor transition metal additions greatly improved the setting property of PSC. However, the concern of metal toxicity was raised, as the material would be used in the human body. In this study, we evaluated the cytotoxicity of PSC in comparison with mineral trioxide aggregate (MTA), which is one of the commercialized materials used for dental root‐end filling. Primary osteoblast cell was used as the target cell. Cell proliferation, cytotoxicity, viability, function, and senescence were analyzed. The cytotoxicity of the PSC‐Zn group (PSC with Zn addition) was similar to that of MTA. PSC‐Zn is not only nontoxic at the cellular level but also has adequate mechanical property, which makes it a potential root‐end filling material for apical surgery. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Increased osteoblast adhesion on nanograined hydroxyapatite and tricalcium phosphate containing calcium titanate
Authors: Ergun Celaletdin , Liu Huinan , Halloran John W. , Webster Thomas J. 
Published: November 2006

AbstractDepending on the coating method utilized and subsequent heat treatments (such as through the use of plasma‐spray deposition), inter‐diffusion of atomic species across titanium (Ti) and hydroxyapatite (HA) coatings may result. These events may lead to structural and compositional changes that consequently cause unanticipated HA phase transformations which may clearly influence the performance of an orthopedic implant. Thus, the objective of the present in vitro study was to compare the cytocompatibility properties of chemistries that may form at the Ti:HA interface, specifically HA, tricalcium phosphate (TCP), HA doped with Ti, and those containing calcium titanate (CaTiO3). In doing so, results of this study showed that osteoblast (bone‐forming cells) adhesion increased with greater CaTiO3 substitutions in either HA or TCP. Specifically, osteoblast adhesion on HA and TCP composites with CaTiO3 was almost 4.5 times higher than that over pure HA. Material characterization studies revealed that enhanced osteoblast adhesion on these compacts may be due to increasing shrinkage in the unit lattice parameters and decreasing grain size. Although all CaTiO3 composites exhibited excellent osteoblast adhesion results, Ca9HPO4(PO4)5OH phase transformation into TCP/CaTiO3 increased osteoblast adhesion the most; because of these reasons, these materials should be further studied for orthopedic applications. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2006
Combined radiofrequency ablation and doxorubicin‐eluting polymer implants for liver cancer treatment
Authors: Weinberg Brent D. , Blanco Elvin , Lempka Scott F. , Anderson James M. , Exner Agata A. , Gao Jinming 
Published: November 2006

AbstractPreviously, biodegradable polymer implants (polymer millirods) to release chemotherapeutic agents directly into tumors have been developed. The purpose of this study is to evaluate local drug distribution from these implants in liver tumors treated with radiofrequency (RF) ablation and determine if the implants provide a therapeutic improvement over RF ablation alone. Cylindrical implants were fabricated using 65% poly(D,L‐lactide‐co‐glycolide) (PLGA), 21.5% NaCl, and 13.5% doxorubicin. Control or drug‐containing millirods were implanted inside VX2 liver tumors (11 mm diameter) in rabbits after RF ablation. Therapeutic efficacy was assessed 4 and 8 days after treatment using tumor size, histology, and fluorescence measurement of drug distribution. Tumors in both test groups recurred at the boundary of the ablated region. Therapeutic doxorubicin concentrations were found in more than 80% of the ablated area, but concentrations declined rapidly at the boundary between normal and ablated tissue. This region was characterized by a developing fibrous capsule with resolving inflammation, which restricted drug transport out of the ablated zone. The intratumoral doxorubicin implants delivered high concentrations of drug within the ablated region but only limited amounts outside the ablation zone. Future studies will focus on overcoming the fibrotic transport barrier and enhancing drug delivery to the periphery of the ablation region to prevent tumor progression. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Fibrinogen adsorption and platelet lysis characterization of fluorinated surface‐modified polyetherurethanes
Authors: Massa T.M. , McClung W.G. , Yang M.L. , Ho J.Y.C. , Brash J.L. , Santerre J.P. 
Published: November 2006

AbstractA polyetherurethane (PU) was modified using fluorinated surface‐modifying macromolecules (SMMs). A double radiolabel method was used simultaneously to measure the number of adhered platelets (51Cr) and the quantity of adsorbed Fg (125I), in a cone‐and‐plate instrument. The objectives were to determine if adsorbed Fg levels correlated to platelet adhesion on the surfaces, and to assess if any reductions in platelet adhesion for the SMM‐treated surfaces resulted from surface‐induced platelet lysis, rather than changes directly related to lower platelet activation and attachment on the novel surfaces. Platelet lysis was determined from lactate dehydrogenase (LDH) and unbound 51Cr released into plasma isolated from whole blood exposed to test materials. The corresponding Fg adsorption, evaluated under the same platelet adhesion conditions, did not account for the reduced platelet adhesion on the treated surfaces. LDH and 51Cr platelet release were very low and indicated no statistically significant differences between the materials. It was therefore concluded that platelet lysis did not contribute to the reduction in platelet adhesion characteristic observed on the SMM‐treated surfaces. More importantly, the work emphasizes that the platelet activation cannot be inferred to by assessing the quantity of fibrinogen as is commonly done in the literature. The finding suggests a much more complex mechanism of action for the SMM surface modifiers. On‐going work is investigating other Fg parameters such as protein binding affinity and protein conformational state in order to establish the mechanism by which the fluorinated surface modifiers may be reducing platelet adhesion via intermediary changes in initial protein adsorption. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Inflammatory response to titanium surfaces with fibrinogen and catalase coatings: An in vitro study
Authors: Göransson A. , Gretzer C. , Tengvall P. , Wennerberg A. 
Published: November 2006

AbstractThe aim of the present study was to evaluate the possibility to modulate the early inflammatory response in vitro by coating titanium surfaces with candidate proinflammatory (fibrinogen coated turned titanium “Fib”) and antiinflammatory proteins (catalase on top of fibrinogen coated turned titanium “Cat”). Additionally, turned titanium surfaces (Ti) were used as controls. The discs were incubated with human mononuclear cells. Adhered cells were investigated with respect to number, viability, differentiation (acute marker 27E10 vs. chronic marker RM3/1), and cytokine production (TNF‐α and IL‐10), after 24 and 72 h. The results indicated that it is possible to modulate the inflammatory response with protein coatings. However, the strongest inflammatory response, indicated by increased number of adhered cells and release of pro and antiinflammatory mediators, was induced by Cat. Furthermore, the cytokine production on this surface was not sensitive to LPS stimulation. Differentiation measured as the expression of the chronic cell surface marker, dominated after 72 h for all surface modifications and Cat displayed an increased number compared to the others. A decrease in the total number of adhered cells and amounts of TNF‐α were observed on all surfaces over time. The cell viability was, in general, high for all tested surfaces. In conclusion, the study proved it possible to influence the early inflammatory response in vitro by immobilizing protein coatings to titanium surfaces. However, the catalase surface demonstrated the strongest inflammatory response, and the possibility to selectively use the potent antiinflammatory capacity of catalase needs to be further evaluated. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Synthesis, characterization, and in vitro activity of antibiotic releasing polyurethanes to prevent bacterial resistance
Authors: Ruggeri V. , Francolini I. , Donelli G. , Piozzi A. 
Published: November 2006

AbstractCentral venous catheters are a major cause of nosocomial bloodstream infections. Different attempts have been made to incorporate antimicrobial agents into catheters, particularly directed at the surface‐coating of devices. To facilitate the antimicrobial adsorption, various cationic surfactants, which however showed several problems, have been used. On the other hand, impregnated catheters with only antimicrobials have demonstrated a short‐term duration due to the difficulties to deliver the drug slowly. Thus, in order to obtain high antimicrobial‐polymer affinity we synthesized or modified polyurethanes to introduce different functional groups. Polymers were loaded with two antibiotics, cefamandole nafate and rifampin (RIF), chosen for both their functional groups and their action spectrum. The in vitro release behavior showed that the elution of drugs depended on the matrix hydrophilicity and on the antibiotic–polymer and antibiotic–antibiotic interactions. To increase the amount of drug released, polyethylene glycol (PEG) used as a pore forming agent at different molecular weights was incorporated in the polymer bulk with antibiotics. As for the in vitro antimicrobial activity of matrices, assessed by Kirby‐Bauer test, it was seen that antibiotics released from various formulations inhibited the bacterial growth and exerted a synergistic effect when both were present. In particular, PEG10000‐containing polymer was active against the RIF‐resistant S. aureus strain up to 23 days. These results suggest that the combined entrapping of antibiotics and pore formers in these novel polymer systems could be promising to prevent the bacterial colonization and to control the emergence of bacterial resistance. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Electrospun fibrinogen: Feasibility as a tissue engineering scaffold in a rat cell culture model
Authors: McManus Michael C. , Boland Eugene D. , Simpson David G. , Barnes Catherine P. , Bowlin Gary L. 
Published: November 2006

AbstractFibrinogen has a well‐established tissue engineering track record because of its ability to induce improved cellular interaction and scaffold remodeling compared to synthetic scaffolds. While the feasibility of electrospinning fibrinogen scaffolds of submicron diameter fibers and their mechanical properties have been demonstrated, in vitro cellular interaction has not yet been evaluated. The goal of this study was to demonstrate, based on cellular interaction and scaffold remodeling, that electrospun fibrinogen can be used successfully as a tissue engineering scaffold. Electrospun fibrinogen scaffolds were disinfected, seeded with neonatal rat cardiac fibroblasts, and cultured for 2, 7, and 14 days. Cultures were treated to regulate scaffold degradation by either supplementing serum‐containing media with aprotinin or crosslinking the scaffolds with glutaraldehyde vapor. Biocompatibility was assessed through a WST‐1 cell proliferation assay. Postculture scaffolds were evaluated by scanning electron microscopy and histology. Cell culture demonstrated that fibroblasts readily migrate into and remodel electrospun fibrinogen scaffolds with deposition of native collagen. Supplementation of culture media with different concentrations of aprotinin‐modulated scaffold degradation in a predictable fashion, but glutaraldehyde vapor fixation was less reliable. Based on the observed cellular interactions, there is tremendous potential for electrospun fibrinogen as a tissue engineering scaffold. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Layer‐by‐layer assembly of polyelectrolyte films improving cytocompatibility to neural cells
Authors: Wu Zhong‐Rong , Ma Jun , Liu Bing‐Fang , Xu Qun‐Yuan , Cui Fu‐Zhai 
Published: November 2006

AbstractThe using of layer‐by‐layer assembly polyelectrolyte (PE) films has been suggested as a new versatile technique for surface modification aimed at tissue engineering and cell‐based chips. In this study, we investigated the surface morphology of the hyaluronic acid (HA)‐based PE films deposited on the amino‐functionalized glass slides using atomic force microscopy. These thin films (bilayer number <9) were measured to have nanoscale roughness ranging from 10 to 100 nm. Then the primary hippocampal and cortical neural cells were cultured on the PE films, respectively. After 5 days of culturing, the cytocompatibility to neural cells was evaluated by cellular morphology, neurite outgrowth, and microtubule‐associated protein 2 expressions. From the present results, the HA‐based PE films were found to be able to support neural cell adhesion and neurite development, especially for the polycation‐ending films. It is suggested these HA‐based multilayer PE films or similar build‐ups could thus be used in the future as a way to modify surfaces for nerve scaffolds and neuron‐based chips. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Thermal oxidation enhances early interactions between human osteoblasts and alumina blasted Ti6Al4V alloy
Authors: Saldaña L. , Barranco V. , González‐Carrasco J.L. , Rodríguez M. , Munuera L. , Vilaboa N. 
Published: November 2006

AbstractOxidation of Ti6Al4V at 500°C for 1 h in air results in the formation of an outer ceramic layer that improves osteoblast behavior and decreases Ti and Al ion release. In this work, alumina blasted Ti6Al4V alloy has been thermally treated and its in vitro biocompatibility has been assessed. Roughness of the blasted alloy was not found significantly altered after heat treatment while chemical surface analysis indicated an increase in stable TiO2 and Al2O3 oxides. Cell attachment, spreading, cytoskeleton organization as well as cell proliferation, viability, and procollagen I peptide secretion of human primary osteoblasts, impaired on alumina blasted Ti6Al4V, were found to be greatly enhanced on the thermally oxidized blasted alloy. Other informative markers of the osteoblastic phenotype such as alkaline phosphatase, osteocalcin, osteoprotegerin, and mineralized nodule formation were evaluated and indicated that osteoblasts responded at the same extent on untreated and thermally treated blasted alloys. Taken together, our in vitro results indicate that thermal oxidation of alumina blasted Ti6Al4V may favor successful osseointegration by promoting early interactions of osteoblastic cells and the modified surface alloy. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res 2007