bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recognition and Ordering at Surfaces: The Importance of Handedness and Footedness
Authors: Mark Andrew G. , Forster Matthew , Raval Rasmita 
Published: April 2011

AbstractThe expression of chirality at surfaces, arising from the adsorption of chiral molecules, is usually discussed in terms of the molecular handedness. However, the adsorption process often leads to a new manifestation of chirality in the form of the adsorption footprint. Therefore, in order to fully define the chirality of the interface we propose that both the handedness and the footedness of the system must be considered. To illustrate this point, we describe the ordering behavior of the molecules tartaric acid, succinic acid, proline, and 3‐pyrroline‐2‐carboxylic (PCA) on a Cu(110) surface using deconvolution maps separating the arrangement of enantiomers, conformers, adsorption footprints and rotamers within an organized assembly. Tartaric and succinic acid mimic the behavior of a conventional 3D conglomerate and racemic compound in terms of both the handedness and footedness, respectively. However, racemic PCA and proline, while expressing a random solid solution of enantiomers and conformers, both display unexpected degrees of order when adsorbate footprint and orientation are considered.
Regioselective Synthesis of 3‐Carbo‐5‐phosphonylpyrazoles through a One‐Pot Claisen–Schmidt/1,3‐Dipolar Cycloaddition/Oxidation Sequence
Authors: Martin Anthony R. , Mohanan Kishor , Toupet Loic , Vasseur Jean‐Jacques , Smietana Michael 
Published: April 2011

AbstractA one‐pot reaction involving an aldehyde, a methyl ketone, and the Bestmann–Ohira reagent has been developed for the synthesis of variously substituted 3‐carbo‐5‐phosphonylpyrazoles. Our synthetic methodology features a domino Claisen–Schmidt/1,3‐dipolar cycloaddition/oxidation sequence, which leads to the target compounds in excellent yields. We further demonstrated that this unprecedented sequence could also be combined with a copper‐catalyzed azide–alkyne cycloaddition in a one‐pot, four‐step cascade process generating five new bonds and two heterocyclic rings.
Integration of 3‐D cell cultures in fluidic microsystems for biological screenings
Authors: Witte Hartmut , Stubenrauch Mike , Fröber Ulrike , Fischer Robert , Voges Danja , Hoffmann Martin 
Published: April 2011

AbstractA life support system for the cultivation of adherent 2‐D and scaffold‐based 3‐D cell cultures in a microfluidic device, a Bio‐Micro‐Electro‐Mechanical System (BioMEMS) is presented. The miniaturization level and system set‐up allow incubator‐independent operation modes and long‐term experiments with real‐time microscope observation. A dedicated seeding procedure for adherent cells into the microstructures is one key issue of the BioMEMS developed. Several seeding methods for the cells were evaluated. Biocompatibility of all materials, surfaces and methods could be demonstrated. First experiments with several cell types show the feasibility of the approach employing standard laboratory protocols. At present, the modular design and set‐up offer a broad application spectrum as well as its future extension to e.g. cultivation of other cell types, coupled cultivation chambers and the implementation of other manipulation or analysis components.
Microfluidic devices and true‐color sensor as platform for glucose oxidase and laccase assays
Authors: Demirkol Dilek Odaci , Dornbusch Kay , Feller Karl‐Heinz , Timur Suna 
Published: April 2011

AbstractThe commonly used assay for measuring glucose oxidase (GOx) and laccase (Lac) activity, based on spectrophotometric test using 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS), has been adapted to measure these enzyme activities via microfluidic devices. The effects of flow rate and concentration of substrates were examined. The developed assays allowed analyzing GOx and Lac activities in the range of 0.8–8.0 Unit (0.1–1.0 mg/mL) and 0.9–17.7 Unit (0.1–2.0 mg/mL), respectively. Moreover, repeatability tests were obtained for both enzyme assays.
Encapsulation of Langerhans' islets: Microtechnological developments for transplantation
Authors: Wiedemeier Stefan , Ehrhart Friederike , Mettler Esther , Gastrock Gunter , Forst Thomas , Weber Matthias M. , Zimmermann Heiko , Metze Josef 
Published: April 2011

AbstractThere is an increasing trend to apply microsystems and microfluidics to solve medical and biomedical tasks. Microfluidic modules are used to modify and manipulate cells and cell clusters for therapeutic applications. Specifically, a method and technical system for encapsulation of Langerhans' islets as an option for the future treatment of diabetes mellitus is described. Type‐1 diabetes patients suffer from an absolute lack of the hormone insulin caused by an autoimmune process destroying the Langerhans' islets. One way to restore glucose‐dependent insulin secretion is the transplantation of human pancreatic islet cells (85% beta cells) from cadaveric donors. However, to prevent the rejection of the transplanted cells by the immune system of the host, a life long immunosuppressive medication is necessary. One possible way to prevent this rejection would be the transplantation of immunoseparated Langerhans' islets, which are encapsulated in a 3D‐alginate matrix polymerized with ions like Ba2+. As has been successfully shown in animal experiments, this technique would furthermore allow the transplantation of xenograft islets and thus help to solve the problem of shortage in donor organs. We present a microfluidics‐based system for encapsulation of cells in alginate.
Effects of potential dietary inhibitors of endogenous DNA damage on mutagenesis and lipid peroxidation in lacZ mice
Authors: Kosinska Wieslawa , Khmelnitsky Michael , Kim Jung Hyun , Zhao Zhong‐Lin , Guttenplan Joseph B. 
Published: April 2011

AbstractThe effects of a nine month administration of dietary: (1) 3H‐1,2‐dithiole‐3‐thione (D3T), (2) N‐acetylcysteine (NAC), (3) antioxidant vitamin mix, (vitamin C+E), (4) free radical scavenger, amifostine, and (5) calorie restriction, (CR), on mutagenesis and lipid peroxidation in lung, kidney, spleen and liver of lacZ transgenic mice were examined. These agents/diets were chosen because they might inhibit certain proposed mechanisms of endogenous damage to DNA. The agents were added to a high fat, reduced antioxidant AIN‐76 diet, to better approximate a Western style diet than the conventional AIN‐76 diet. As the lacZ gene is not expressed, mutations in that gene are neutral, and simply accumulate over time. The mutant fractions in control mice increased about 50–100%. Most of the agents inhibited to various extents the age‐related increase in mutagenesis in lung, kidney, and/or spleen, but no inhibition was observed in liver. There was no significant effect of age on lipid peroxidation levels in controls, possibly reflecting steady state turnover of lipid peroxidation products. Almost all of the treatments except D3T inhibited lipid peroxidation in most organs to different degrees. The vitamin C+E mix was the most effective at inhibiting lipid peroxidation, but a single most effective inhibitor of mutagenesis could not be discerned. Some associations were observed between the reduction in lipid peroxidation and the inhibition of mutagenesis. The results are consistent with a partial role for oxidative stress in the age‐related increase in mutagenesis. These observations may have implications for chemoprevention of carcinogenesis. Environ. Mol. Mutagen., 2011. © 2011 Wiley‐Liss, Inc.
Fenthion and terbufos induce DNA damage, the expression of tumor‐related genes, and apoptosis in HEPG2 cells
Authors: Wu Jong‐C. , Hseu You‐Cheng , Tsai Jui‐Shan , Chen Lei‐Chin , Chye Soi M. , Chen Chin‐H. , Ching Chen Ssu 
Published: April 2011

AbstractThis study investigates the effects of fenthion and terbufos, two organophosphorous pesticides, on DNA damage, tumor‐related gene expression, and apoptosis in HepG2 cells. We found that exposure to concentrations ranging from 50 to 200 μM of fenthion and terbufos for 2 hr caused significant death in HepG2 cells. Both compounds induced DNA damage in a concentration‐dependent manner as measured using the alkaline comet assay. Tumor‐related genes (jun, myc, andfos) and apoptosis‐related genes (socs3, tnfaip3, ppp1r15a, andnr4a1) were up‐regulated by both compounds. Finally, both compounds induced apoptosis. The results demonstrate that both terbufos and fenthion induce DNA damage and should be considered potentially hazardous to humans. Environ. Mol. Mutagen., 2011. © 2011 Wiley‐Liss, Inc.
Characterization of environmental chemicals with potential for DNA damage using isogenic DNA repair‐deficient chicken DT40 cell lines
Authors: Yamamoto Kimiyo N. , Hirota Kouji , Kono Koichi , Takeda Shunichi , Sakamuru Srilatha , Xia Menghang , Huang Ruili , Austin Christopher P. , Witt Kristine L. , Tice Raymond R. 
Published: April 2011

AbstractIncluded among the quantitative high throughput screens (qHTS) conducted in support of the US Tox21 program are those being evaluated for the detection of genotoxic compounds. One such screen is based on the induction of increased cytotoxicity in seven isogenic chicken DT40 cell lines deficient in DNA repair pathways compared to the parental DNA repair‐proficient cell line. To characterize the utility of this approach for detecting genotoxic compounds and identifying the type(s) of DNA damage induced, we evaluated nine of 42 compounds identified as positive for differential cytotoxicity in qHTS (actinomycin D, adriamycin, alachlor, benzotrichloride, diglycidyl resorcinol ether, lovastatin, melphalan, trans‐1,4‐dichloro‐2‐butene, tris(2,3‐epoxypropyl)isocyanurate) and one non‐cytotoxic genotoxic compound (2‐aminothiamine) for (1) clastogenicity in mutant and wild‐type cells; (2) the comparative induction of γH2AX positive foci by melphalan; (3) the extent to which a 72‐hr exposure duration increased assay sensitivity or specificity; (4) the use of 10 additional DT40 DNA repair‐deficient cell lines to better analyze the type(s) of DNA damage induced; and (5) the involvement of reactive oxygen species in the induction of DNA damage. All compounds but lovastatin and 2‐aminothiamine were more clastogenic in at least one DNA repair‐deficient cell line than the wild‐type cells. The differential responses across the various DNA repair‐deficient cell lines provided information on the type(s) of DNA damage induced. The results demonstrate the utility of this DT40 screen for detecting genotoxic compounds, for characterizing the nature of the DNA damage, and potentially for analyzing mechanisms of mutagenesis. Environ. Mol. Mutagen., 2011. © 2011 Wiley‐Liss, Inc.y
Semiactive fuzzy control of the seismic response of building frames with MR dampers
Authors: Das Diptesh , Datta T. K. , Madan Alok 
Published: April 2011

AbstractA fuzzy‐logic control algorithm, based on the fuzzification of the MR damper characteristics, is presented for the semiactive control of building frames under seismic excitation. The MR damper characteristics are represented by force–velocity and force–displacement curves obtained from the sinusoidal actuation test. The method does not require any analytical model of MR damper characteristics, such as the Bouc‐Wen model, to be incorporated into the control algorithm. The control algorithm has a feedback structure and is implemented by using the fuzzy‐logic and Simulink toolboxes of MATLAB. The performance of the algorithm is studied by using it to control the responses of two example buildings taken from the literature—a three‐storey building frame, in which controlled responses are obtained by clipped‐optimal control and a ten‐storey building frame. The results indicate that the proposed scheme provides nearly the same percentage reduction of responses as that obtained by the clipped‐optimal control with much less control force and much less command voltage. Position of the damper is found to significantly affect the controlled responses of the structure. It is observed that any increase in the damper capacity beyond a saturation level does not improve the performance of the controller. Copyright © 2011 John Wiley & Sons, Ltd.
Nonstationary seismic responses of structure with nonlinear stiffness subject to modulated Kanai–Tajimi excitation
Authors: Jin X. L. , Huang Z. L. , Leung A. Y. T. 
Published: April 2011

SUMMARYA simple structure under earthquake excitation is modeled as a single‐degree‐of‐freedom system with nonlinear stiffness subject to modulated Kanai–Tajimi excitation. The nonstationary responses including the nonstationary probability densities of the system responses and the statistical moments are obtained in semi‐analytical form. By applying the stochastic averaging method based on the generalized harmonic functions, the averaged Fokker–Planck–Kolmogorov(FPK) equation governing the nonstationary probability density of the amplitude is derived. Then, the solution of the FPK equation is approximately expressed by a series expansion in terms of a set of properly selected basis functions with time‐dependent coefficients. According to the Galerkin method, the time‐dependent coefficients are solved from a set of linear first‐order differential equations. Thus, the nonstationary probability densities of the amplitude and the state responses as well as the statistic moments of the amplitude are obtained. Finally, two types of the modulating functions, i.e. constant function and exponential function, are considered to give some semi‐analytical formulae. The proposed procedures are checked against the Monte Carlo simulation. The effects of the structure natural frequency and the intensity of the excitation as well as the ground stiffness on the system responses are discussed. It should be pointed out that the proposed method is good for broadband excitation and light damping. Copyright © 2011 John Wiley & Sons, Ltd.
Is the pig a good umami sensing model for humans? A comparative taste receptor study
Authors: Roura Eugeni , Humphrey Brooke , Klasing Kirk , Swart Marcel 
Published: April 2011

ABSTRACTThe diversity of taste perception across species reflects a dietary adaptation to different ecological niches. Laboratory rodents have been widely used as models for human nutritional studies including the understanding of peripheral chemosensing. Nevertheless the diet type as well as the anatomical and functional features of bigger mammals such as the pig may merit further consideration as models for humans. Recently, the porcine umami taste receptor pTas1r1/pTas1r3 and porcine mGluR4 gene sequences have become available. The aim of this study was to compare the umami sensing biology with emphasis in T1R1 sequences, Venus flytrap (VFT) ligand binding domains and l‐amino acid agonists of several mammalian species including human, pig and laboratory rodents. Compared to their corresponding human gene orthologues, receptor homologies where highest for the dog (T1r1 and T1r3) and the pig (mGluR4) and lowest for the mouse (T1r1, T1r3 and mGluR4). Th human T1R1 VFT domain contains 10 different amino acid residues critically involved in ligand binding. All 10 amino acid residues are conserved, both in terms of type and location, within the pig VFT domain. In turn, the arginine and histidine (both charged polar) residues at key positions 307 and 308 appear as threonine and tyrosine (both neutral polar) residues in mouse and rat sequences. Comparison of derived molecular models seems to offer a good explanation regarding the differences of in vivo preference data for l‐amino acids in rats, pigs and humans. Overall, the umami sensing in pigs show higher similarity to that in humans than the umami sensing in laboratory rodents. Copyright © 2011 John Wiley & Sons, Ltd.
Lost and found in sweeteners: forgotten molecules and unsolved problems in the chemistry of sweet compounds
Authors: Bassoli Angela , Borgonovo Gigliola , Morini Gabriella 
Published: April 2011

ABSTRACTThe chemistry of sweet compounds has been an ideal training ground for researchers in the field of taste for a very long time. Sweeteners have a huge importance in the food and pharmaceutical industries, but they have also attracted much interest in connection with their biological function and the general mechanism of action of sweet compounds. Several factors contributed to a large and varied production of scientific data in this field: among these the existence of several active compounds in the plant kingdom, the diversity of structural, stereochemical and conformational hallmarks, the intriguing aspects related to their modulation, inhibition and synergy. Among all molecules that have been isolated and synthesized, only a few have successfully reached the final goal of commercial development while some have been used to derive models and structure–activity relationships. Nevertheless, there is a number of very interesting compounds of natural or synthetic origin that – after a short period of popularity – were apparently lost or forgotten, without any further development. The article will give an overview on some of these compounds and discuss, in the light of current knowledge, the contribution that chemistry still could give in the sweeteners area. Copyright © 2011 John Wiley & Sons, Ltd.
Combining a level‐set method and a mixed stabilized P1/P1 formulation for coupling Stokes–Darcy flows
Authors: Pacquaut G. , Bruchon J. , Moulin N. , Drapier S. 
Published: April 2011

SUMMARYThe aim of this work is to focus on the Stokes–Darcy coupled problem in order to simulate numerically, with the finite element method, composite manufacturing processes based on liquid resin infusion. In this study, a macroscopic description is used. The computational domain can be divided into two non‐miscible sub‐domains: a purely fluid domain and a porous medium. In the purely fluid domain, the fluid flows according to the Stokes equations, while in the porous medium, the fluid flows into the preforms according to the Darcy equations. Specific conditions have to be considered on the fluid/porous medium interface. The corresponding weak formulation is obtained by summing up the variational forms of the Stokes and Darcy equations over the whole domain. It is solved by a mixed velocity/pressure finite element method. In the purely fluid domain, a first‐order mixed P1+/ P1 finite element is used. However, in the porous medium, the Ladysenskaya–Brezzi–Babuska stability condition is not satisfied, and a P1/P1 finite element is preferred. It is stabilized with the Hughes Variational Multiscale formulation. The originality of our approach is two fold. First, one single unstructured mesh is considered for the whole domain. Second, the interface between the purely fluid domain and the porous medium is represented by a level‐set function. The level‐set framework is also used to capture the resin flow front. At the end of this paper, numerical simulations of such manufacturing processes by resin infusion/injection are presented. Copyright © 2011 John Wiley & Sons, Ltd.
A parallel finite element sliding mesh technique for the simulation of viscous flows in agitated tanks
Authors: Rivera Christian A. , Heniche Mourad , Bertrand François , Glowinski Roland , Tanguy Philippe A. 
Published: April 2011

SUMMARYA parallel sliding mesh algorithm for the finite element simulation of viscous fluid flows in agitated tanks is presented. Lagrange multipliers are used at the sliding interfaces to enforce the continuity between the fixed and moving subdomains. The novelty of the method consists of the coupled solution of the resulting velocity–pressure‐Lagrange multipliers system of equations by an ILU(0)‐QMR solver. A penalty parameter is introduced for both the interface and the incompressibility constraints to avoid pivoting problems in the ILU(0) algorithm. To handle the convective term, both the Newton–Raphson scheme and the semi‐implicit linearization are tested. A penalty parameter is introduced for both the interface and the incompressibility constraints to avoid the failure of the ILU(0) algorithm due to the lack of pivoting. Furthermore, this approach is versatile enough so that it allows partitioning of sliding and fixed subdomains if parallelization is required. Although the sliding mesh technique is fairly common in CFD, the main advantage of the proposed approach is its low computational cost due to the inexpensive and parallelizable calculations that involve preconditioned sparse iterative solvers. The method is validated for Couette and coaxial stirred tanks. Copyright © 2011 John Wiley & Sons, Ltd.
A random walk down the options market
Authors: Jiang George J. , Tian Yisong S. 
Published: April 2011

AbstractUnder the efficient market hypothesis, option‐implied forward variance forms a martingale and changes in forward variance follow a random walk. In this study, we extract forward variance from option prices following a model‐free approach and empirically test the random walk hypothesis. Although results from standard orthogonality tests support the martingale restriction, further results from autoregressive regressions seem to reject the martingale restriction as daily changes in forward variance are found to exhibit negative autocorrelation. However, this anomalous pattern of negative correlation is fully explained by illiquidity effects. Overall, the findings support the random walk hypothesis and informational efficiency of the options market. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark 32:505–535, 2012
Ageing in people with autistic spectrum disorder
Authors: Mukaetova‐Ladinska E. B. , Perry E. , Baron M. , Povey C. ,   on behalf of the Autism Ageing Writing Group
Published: April 2011

BackgroundAlthough autism in children and in adults attracts attention with respect to clinical and research needs, autism in the older individuals has not been considered to any degree. We review the evidence for urgently addressing the question of ageing in people with autistic spectrum disorder (ASD), focusing on those with disability.MethodsPerspectives are reviewed in relation to demographics, experiences of relatives or carers, anticipated residential care needs, requirement for specifically designed cognitive assessment tools and importance of initiating new brain ageing research initiatives in this area.ResultsWith escalating numbers of ASD individuals with disability reaching old age, provision of care is the paramount issue that is only beginning to be addressed in a few European communities and in the USA. How ageing affects cognition in such individuals as they reach an age no longer consistent with parental care is unknown, lacking any published evidence, and there is a clear need to design cognitive and behavioural assessment tools appropriate to ageing in ASD individuals with disability, as was the case with respect to dementia as a whole. Although there is a growing body of evidence on pathological, imaging, neuropharmacological and other key brain abnormalities in ASD, these are, to date, confined to children and young (only rarely to middle aged) adults.ConclusionsThe need for new initiatives in research into ageing in ASD is urgent. Apart from a growing care crisis, the prospect of understanding brain ageing in this population may bring potential rewards beyond immediate clinical need given the precedent of Down syndrome. Copyright © 2011 John Wiley & Sons, Ltd.