bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical modelling and measurement of cell trajectories in 3‐D under the influence of dielectrophoretic and hydrodynamic forces
Authors: Holzner Felix , Hagmeyer Britta , Schütte Julia , Kubon Massimo , Angres Brigitte , Stelzle Martin 
Published: November 2012

AbstractThis research is part of a program aiming at the development of a fluidic microsystem for in vitro drug testing. For this purpose, primary cells need to be assembled to form cellular aggregates in such a way as to resemble the basic functional units of organs. By providing for in vivo‐like cellular contacts, proper extracellular matrix interaction and medium perfusion it is expected that cells will retain their phenotype over prolonged periods of time. In this way, in vitro test systems exhibiting in vivo type predictivity in drug testing are envisioned. Towards this goal a 3‐D microstructure micro‐milled in a cyclic olefin copolymer (COC) was designed in such a way as to assemble liver cells via insulator‐based dielectrophoresis (iDEP) in a sinusoid‐type fashion. First, numeric modelling and simulation of dielectrophoretic and hydrodynamic forces acting on cells in this microsystem was performed. In particular, the problem of the discontinuity of the electric field at the interface between the fluid media in the system and the polymer materials it consists of was addressed. It was shown that in certain cases, the material of the microsystem may be neglected altogether without introducing considerable error into the numerical solution. This simplification enabled the simulation of 3‐D cell trajectories in complex chip geometries. Secondly, the assembly of HepG2 cells by insulator‐based dielectrophoresis in this device is demonstrated. Finally, theoretical results were validated by recording 3‐D cell trajectories and the Clausius–Mossotti factor of liver cells was determined by combining results obtained from both simulation and experiment.
Electrokinetic motion of a deformable particle: Dielectrophoretic effect
Authors: Ai Ye , Mauroy Benjamin , Sharma Ashutosh , Qian Shizhi 
Published: November 2012

AbstractElectrokinetics‐induced motion and deformation of a hyperelastic particle confined in a slit microchannel has been numerically investigated for the first time with a full consideration of the fluid–particle–electric field interactions and the dielectrophoretic (DEP) effect. When the initial orientation of a cylindrical particle with respect to the applied electric field, θp0, is 90°, the particle tends to curl up as a “C” shape when moving from left to right. The electrokinetics‐induced particle deformation is due to the joint effects of the shear force arising from the non‐uniform Smoluchowski slip velocity on the particle surface and the asymmetric DEP force with respect to the center of the deformed particle arising from the spatially non‐uniform electric field surrounding the particle. The electrokinetics‐induced particle deformation is opposite to that of a particle moving in the same direction subjected to a pressure‐driven flow. When the initial particle orientation is 0<θp0<90°, a net torque arising from the DEP effect progressively rotates and aligns the particle with its longest axis parallel to the applied electric field, thus decreasing the non‐uniformity of the electric field and accordingly the particle deformation. The numerical predictions are in qualitative agreement with our previous experimental observation. The results show that the DEP effect is significant and must be taken into account in the modeling of electrokinetic motion of a deformable particle in microfluidics.
Electrodeless dielectrophoresis for bioanalysis: Theory, devices and applications
Authors: Regtmeier Jan , Eichhorn Ralf , Viefhues Martina , Bogunovic Lukas , Anselmetti Dario 
Published: November 2012

AbstractDielectrophoresis is a non‐destructive, label‐free method to manipulate and separate (bio‐) particles and macromolecules. The mechanism is based on the movement of polarizable objects in an inhomogeneous electric field. Here, microfluidic devices are reviewed that generate those inhomogeneous electric fields with insulating posts or constrictions, an approach called electrodeless or insulator‐based dielectrophoresis. Possible advantages compared to electrode‐based designs are a less complex, monolithic fabrication process with low‐cost polymeric substrates and no metal surface deterioration within the area of sample analysis. The electrodeless design has led to novel devices, implementing the functionality directly into the channel geometry and covering many areas of bioanalysis, like manipulation and separation of particles, cells, DNA, and proteins.
Interactions between chemical and climate stressors: A role for mechanistic toxicology in assessing climate change risks
Authors: Hooper Michael J. , Ankley Gerald T. , Cristol Daniel A. , Maryoung Lindley A. , Noyes Pamela D. , Pinkerton Kent E. 
Published: November 2012

Abstract
Incorporation of global climate change (GCC) effects into assessments of chemical risk and injury requires integrated examinations of chemical and nonchemical stressors. Environmental variables altered by GCC (temperature, precipitation, salinity, pH) can influence the toxicokinetics of chemical absorption, distribution, metabolism, and excretion as well as toxicodynamic interactions between chemicals and target molecules. In addition, GCC challenges processes critical for coping with the external environment (water balance, thermoregulation, nutrition, and the immune, endocrine, and neurological systems), leaving organisms sensitive to even slight perturbations by chemicals when pushed to the limits of their physiological tolerance range. In simplest terms, GCC can make organisms more sensitive to chemical stressors, while alternatively, exposure to chemicals can make organisms more sensitive to GCC stressors. One challenge is to identify potential interactions between nonchemical and chemical stressors affecting key physiological processes in an organism. We employed adverse outcome pathways, constructs depicting linkages between mechanism-based molecular initiating events and impacts on individuals or populations, to assess how chemical- and climate-specific variables interact to lead to adverse outcomes. Case examples are presented for prospective scenarios, hypothesizing potential chemical–GCC interactions, and retrospective scenarios, proposing mechanisms for demonstrated chemical–climate interactions in natural populations. Understanding GCC interactions along adverse outcome pathways facilitates extrapolation between species or other levels of organization, development of hypotheses and focal areas for further research, and improved inputs for risk and resource injury assessments. Environ. Toxicol. Chem. 2013;32:32–48. © 2012 SETAC
One‐Step Sonochemical Synthesis of Reduced Graphene Oxide/Pt/Sn Hybrid Materials and Their Electrochemical Properties
Authors: Anandan S. , Manivel A. , Ashokkumar M. 
Published: November 2012

AbstractLow frequency ultrasound (20 kHz) was used for the reduction of graphene oxide (GO), Pt and Sn precursors with simultaneous loading of Pt and Sn monometallic and Pt–Sn bimetallic nanoparticles on the surface of reduced GO (rGO). The physicochemical characterizations of the catalysts were carried out using transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), energy dispersive X‐ray spectroscopy (EDX), and selected area electron diffraction (SAED) techniques. The reduced monometallic and bimetallic nanoparticles were spherical in shape with diameters around 2–6 nm, uniformly embedded on rGO sheets of few layers thickness. The electrocatalytic activities of the synthesized materials were evaluated by cyclic voltammetric studies.
Local Structure of Rare Earth Niobates (RE3NbO7, RE = Y, Er, Yb, Lu) for Proton Conduction Applications▴
Authors: López‐Conesa L. , Rebled J. M. , Chambrier M. H. , Boulahya K. , González‐Calbet J. M. , Braida M. D. , Dezanneau G. , Estradé S. , Peiró F. 
Published: November 2012

AbstractStructural properties of rare earth niobates (RE3NbO7, RE = Y, Er, Yb, Lu) have been studied using selected area electron diffraction (SAED) and high resolution transmission electron microscopy (HRTEM). SAED patterns show diffuse scattering features along the [111] direction of the pure fluorite (Fm–3m) structure due to a short‐range ordering of anion vacancies in the fluorite structure or the change of coordination number around some cations. The latter is related to the presence of small domains of pyrochlore phase (Fd‐3m), which are observed in the HRTEM images.
Investigation on accelerating FFT‐based methods for the EFIE on graphics processors
Authors: Attardo Elia A. , Francavilla Matteo A. , Vipiana Francesca , Vecchi Giuseppe 
Published: November 2012

SUMMARYThe use of graphic processor units (GPUs) has been recently proposed in computational electromagnetics to accelerate the solution of the electric field integral equation. In these methods, the linear systems obtained by using boundary elements are considered, and then an accelerated solution for a specific excitation is obtained. The existing studies are mostly focused on speeding up the filling time or the LU decomposition of that matrix. This limits the application to simple simulation scenarios if a fast method is not employed. In this paper, we propose a GPU acceleration for FFT‐based integral equation solvers. We will investigate the operations involved in the solver, and we will motivate the use of GPUs. Results of numerical tests will be reported firstly on a perfect electric conductor sphere with different radii; then a realistic aircraft will be considered. We found that using GPUs for FFT‐based methods allows achieving a reasonable speed‐up. Copyright © 2012 John Wiley & Sons, Ltd.
Statins may reduce femoral osteolysis in patients with total Hip arthroplasty
Authors: Lübbeke Anne , Garavaglia Guido , Rothman Kenneth J. , Bonvin Alexis , Roussos Constantinos , Miozzari Hermes , Hoffmeyer Pierre 
Published: November 2012

AbstractIn experimental studies, statin use has been associated with reduction of osteoclastic activity and promotion of bone formation around implants. Moreover, a large clinical study recently reported a substantially reduced risk of revision for aseptic loosening among statin users with THA. Our objective was to evaluate the influence of statin use on the development of femoral osteolysis within 5 years after THA. We conducted a case‐cohort study including all THAs presenting with femoral osteolysis at the 5 year visit (cases) and compared them with those without osteolysis (controls). Cases and controls were identified from a cohort of primary THAs operated between 2001 and 2005. Seven hundred thirty‐five THAs were included, mean age 68 years. Five years after surgery osteolysis had developed around the femoral component of 40 THAs (5.4%). Ever‐use of statins was much less frequent among cases (5 of 40, 12.5%) than among controls (199 of 695, 28.6%). The crude risk ratio of femoral osteolysis among statin users was 0.36 (95% CI 0.14; 0.92). After adjusting for age, sex, activity level, BMI, diagnosis, bearing surface, and type of stem, the adjusted risk ratio was 0.38 (95% CI 0.15; 0.99). In conclusion, statin use was associated with a reduced risk of developing femoral osteolysis 5 years after THA. Statins may be useful for reducing the risk of implant failure following THA. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 814–820, 2013
Neuromuscular electrical stimulation (NMES) reduces structural and functional losses of quadriceps muscle and improves health status in patients with knee osteoarthritis
Authors: Vaz Marco Aurélio , Baroni Bruno Manfredini , Geremia Jeam Marcel , Lanferdini Fábio Juner , Mayer Alexandre , Arampatzis Adamantios , Herzog Walter 
Published: November 2012

AbstractKnee osteoarthritis (OA) is associated with quadriceps atrophy and weakness, so muscle strengthening is an important point in the rehabilitation process. Since pain and joint stiffness make it often difficult to use conventional strength exercises, neuromuscular electrical stimulation (NMES) may be an alternative approach for these patients. This study was aimed at (1) identifying the associations of knee OA with quadriceps muscle architecture and strength, and (2) quantifying the effects of a NMES training program on these parameters. In phase 1, 20 women with knee OA were compared with 10 healthy female, asymptomatic, age‐matched control subjects. In phase 2, 12 OA patients performed an 8‐week NMES strength training program. OA patients presented smaller vastus lateralis thickness (11.9 mm) and fascicle length (20.5%) than healthy subjects (14.1 mm; 24.5%), and also had a 23% smaller knee extensor torque compared to the control group. NMES training increased vastus lateralis thickness (from 12.6 to 14.2 mm) and fascicle length (from 19.6% to 24.6%). Additionally, NMES training increased the knee extensor torque by 8% and reduced joint pain, stiffness, and functional limitation. In conclusion, OA patients have decreased strength, muscle thickness, and fascicle length in the knee extensor musculature compared to control subjects. NMES training appears to offset the changes in quadriceps structure and function, as well as improve the health status in patients with knee OA. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 511–516, 2013
Photo‐controlled Hierarchical Assembly and Fusion of Coumarin‐containing Polydiacetylene Vesicles
Authors: Li Jingguo , Jiang Hao , Hu Wenlong , Xia Hongyan , Zou Gang , Zhang Qijin 
Published: November 2012

AbstractHerein, we synthesize a coumarin‐substituted diacetylene monomer (CODA) and report the novel photo‐controlled reversible assembly and disassembly behavior of the polymerized CODA (PCODA) vesicles. The photo‐triggered dimerization and cleavage reactions of the coumarin groups within the surface of the adjacent PCODA vesicles can be utilized as the driving force to induce assembly and disassembly of PCODA vesicles. Moreover, the boundary of PCODA vesicles in the aggregates becomes more obscure when the irradiation time exceeds 30 min. Fusion occurs upon close docking of target membranes, driven by sufficient dimerization of the coumarin groups within the surface of PCODA vesicles.
WYE‐120318, a ring contraction product of methylnaltrexone, and structure revision of coniothyrione
Authors: Kong Fangming , Zhu Tianmin , Pan Weitao , Tsao Russ , Pagano Thomas G. , Nguyen Bao , Marquez Brian 
Published: November 2012

A contracted ring degradation product, WYE‐120318 (compound 2), was discovered during the development phase for methylnaltrexone bromide (compound 1) drug substance. The compound was isolated by high‐performance liquid chromatography fractionation, and its structure was determined by spectroscopic data analyses. WYE‐120318 is formed from methylnaltrexone through a benzyl‐benzilic acid type rearrangement reaction to yield an α‐hydroxy‐cyclopentanecarboxylic acid substructure. The proposed structure and the formation mechanism are confirmed by the synthesis of WYE‐120318 from methylnaltrexone (compound 1).A similar benzyl‐benzilic acid type rearrangement reaction can be envisioned as the biological origin of remisporine A (compound 3), a naturally occurring cyclopentadienyl compound that autocatalytically dimerizes to remisporine B (compound 4). The structure of remisporine A was deduced from its dimer 4. Coniothyione (compound 5) can be considered as the first example of a stable natural product bearing the remisporine A skeleton. However, the regiochemistry of the chlorosubstitution in the coniothyrione structure needs to be revised to compound 6 on the basis of the nuclear magnetic resonance data and biogenesis analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Kit ligand and glial‐derived neurotrophic factor as alternative supplements for activation and development of ovine preantral follicles in vitro
Authors: Esmaielzadeh F. , Hosseini S.M. , Nasiri Z. , Hajian M. , Chamani M. , Gourabi H. , Shahverdi A.H. , Vosough A.D. , Nasr‐Esfahani M.H. 
Published: November 2012

AbstractIn vitro growth of preantral follicles has the potential to produce considerable numbers of competent oocytes for use in medicine, agriculture, and even wildlife conservation. The critical regulatory role of growth factors and hormones in the development of preantral follicles has been established. This study investigated the effect of glial‐derived neurotropic factor (GDNF) and kit ligand (KL) on the in vitro development of ovine preantral follicles. Results indicated that both GDNF and KL significantly improved activation of primordial follicles, similar to co‐addition of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF), which are commonly used for in vitro follicular development. Importantly, GDNF had a more profound effect on follicle health, development, and differentiation compared with KL alone. Furthermore, the combination of GDNF and KL in the presence of EGF and bFGF had a positive, synergic effect on health, development, and differentiation of preantral follicles, as determined by histological and hormonal assessments. The results of this study may provide a foundation for further studies that will unravel the molecular mechanisms of follicular development to further improve the current status of in vitro preantral follicle culture. Mol. Reprod. Dev. 80: 35–47, 2013. © 2012 Wiley Periodicals, Inc.
Gentherapie der Hämophilie B
Authors: Winckler Thomas 
Published: November 2012

AbstractDie Bluterkrankheit (Hämophilie) ist eine typische Indikation für die Substitutionstherapie mit Blutgerinnungsfaktor‐Konzentraten oder Biopharmazeutika – und bald vielleicht auch für eine Gentherapie.
Alternative Wege zu “Multidrug”‐resistenten Bakterien via reaktiver Sauerstoffspezies
Authors: Holzgrabe Ulrike 
Published: November 2012

AbstractInzwischen kennen wir eine ganze Reihe von Mechanismen, wie Bakterien eine Antibiotika‐Resistenz entwickeln können, wie z.B. den horizontalen Transfer von Resistenz‐Genen, die Antibiotika‐selektive Selektion von natürlich vorkommenden, resistenten Stämmen einer Population oder die gesteigerte Mutagenese in sog. “Hypermutator”‐Stämmen. Kohanski et al. berichteten kürzlich über die Entwicklung von Multiresistenzen bei der Gabe von subletalen Antibiotikadosen verursacht durch reaktive Sauerstoffspezies wie Hydroxyl‐Radikale.
Dielectric and electric properties of plasticized PEO‐AgCF3SO3‐SiO2 nanocomposite polymer electrolyte system
Authors: Gondaliya Nirali , Kanchan D.K. , Sharma Poonam , Jayswal Manish S. 
Published: November 2012

AbstractThe effect of plasticizer poly(ethylene glycol) (PEG) on dielectric and electrical properties of an ionically conducting polymer nanocomposite electrolyte PEO: AgCF3SO3: SiO2: PEG has been investigated. The variation of relative dielectric constant and tangent loss peak with frequency have been discussed. The ionic and polymer segmental motions have been analyzed by electrical modulus and dielectric permittivity. The electrical modulus formalism is used to study the ionic relaxation process in these composites in terms of conductivity relaxation time. On addition of plasticizer, the modulus peak shifts toward higher frequency side suggesting the speeding up of the relaxation time. The frequency dependence of AC conductivity follows the universal power law. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Haemolysis risk in methylene blue treatment of G6PD‐sufficient and G6PD‐deficient West‐African children with uncomplicated falciparum malaria: a synopsis of four RCTs
Authors: Müller Olaf , Mockenhaupt Frank P. , Marks Bernd , Meissner Peter , Coulibaly Boubacar , Kuhnert Ronny , Buchner Hannes , Schirmer R. Heiner , Walter‐Sack Ingeborg , Sié Ali , Mansmann Ulrich 
Published: November 2012

ABSTRACTPurposeMethylene blue (MB), which was recently tested in a number of clinical malaria studies in Burkina Faso, is currently investigated for its benefit when added to artemisinin‐based combination therapy. Together with a number of other antimalarials, MB is on the list of drugs which potentially induce haemolysis in patients with G6PD deficiency. Ruling out safety concerns is of major importance during drug development.MethodsA pooled analysis was performed with patient data from four clinical studies conducted in West African children with falciparum malaria between 2003 and 2007. The primary endpoints were haemoglobin levels over time as well as haemolysis in G6PD‐deficient (n = 199) and G6PD‐sufficient (n = 806) children treated with MB‐containing (n = 844) compared to children without MB‐containing (n = 161) drug regimens.ResultsIn the chosen model, the haemoglobin time course was significantly influenced by the G6PD genotype and the MB dose. In children with hemi‐ or homozygous G6PD (A‐) deficiency, MB treatment with 15 mg/kg per day was associated with a significant reduction in Hb values which reached a minimum of 8.5 g/dl. Two episodes of haemolysis occurred (out of 1005 children); one in a girl heterozygous for G6PD deficiency and one in a hemizygous boy, both had received MB.ConclusionsMB treatment of malaria in Africa is associated with slightly reduced haemoglobin values in children with a full G6PD defect compared to non‐G6PD deficient children. This effect appears to be of limited clinical relevance but needs to be monitored. Copyright © 2012 John Wiley & Sons, Ltd.
Conformational and thermal analyses of α‐methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers
Authors: Izunobi Josephat U , Higginbotham Clement L 
Published: November 2012

AbstractHybrid block copolymers find applications in drug delivery, tissue engineering, biomimetics and bioimaging, amongst others, mainly due to their propensity to form phase‐separated microdomains as well as to the aggregation of their polypeptide segments. They not only enhance control over structure at the nanometre scale but also yield materials that can interface with various biosystems for different utilities. α‐Methoxy‐poly(ethylene glycol)‐block‐poly[ϵ‐(benzyloxycarbonyl)‐l‐lysine] hybrid block copolymers of varying degrees of polymerization, MPEGn‐b‐PLL(Z)m, were synthesized by N‐carboxyanhydride ring‐opening polymerization and characterized using infrared and NMR spectroscopy and gel permeation chromatography. Their secondary structures and bulk conformations were investigated using circular dichroism spectroscopy and wide‐angle X‐ray diffraction, respectively, whereas thermogravimetric analysis (TGA), derivative TGA and differential scanning calorimetry were employed for thermal analyses. The resulting block copolymers exhibited microphase separation and suppressed degrees of crystallinity with increasing l‐lysine content and adopted α‐helix and β‐sheet secondary structures in aqueous milieu. The copolymers were also more thermally stable than their constituent homopolymers. Interestingly, the effects of the retention of the Nϵ‐benzyloxycarbonyl moiety on polymer properties proved considerable. The hybrid block copolymers herein afforded hierarchical structures of potential utility in the biomedical and pharmaceutical fields. © 2012 Society of Chemical Industry