bluuebunny/crossref_metadata_2025 huggingface dataset:
Dyes in Liquid Crystals: Experimental and Computational Studies of a Guest–Host System Based on a Combined DFT and MD Approach
Authors: Sims Mark T. , Abbott Laurence C. , Cowling Stephen J. , Goodby John W. , Moore John N.
Published: June 2015

Practical applications of guest–host liquid crystal systems are critically dependent on the alignment of the guest species within the liquid crystal host. UV/Vis absorption spectroscopy shows that the 1,5‐dihydroxy‐2,6‐bis‐(4‐propylphenyl)‐9,10‐anthraquinone dye aligns within the E7 nematic host, giving an experimental dichroic ratio of 9.40 and dye order parameter of 0.74. This alignment was modelled by using a combination of density functional theory (DFT) and molecular dynamics (MD) computational approaches that do not require the input of experimental data. Time‐dependent DFT calculations show that the electronic transition dipole moment is highly aligned with the long molecular axis of the dye. Fully atomistic MD simulations show that the long axis of the dye is less highly aligned within the E7 host, indicating that this contribution limits the overall dye alignment and, thereby, the potential practical applications of this particular system. Importantly, this study demonstrates an experimental and combined DFT and MD computational approach that may be applied generally to guest–host systems, providing a potential route to their rational design.
Reaction of Ni2+ and SnS as a Way to Form Ni@SnS and Sn2Ni3S2 Nanocrystals: Control of Product Formation and Shape
Authors: Rommel Stefan Michael , Weihrich Richard
Published: June 2015

Reductive diffusion of Ni2+ into SnS particles was shown to selectively form Sn2Ni3S2, hybrid, or even core‐shell Ni@SnS, Ni1.523Sn, and Ni3S2, by tuning the reaction conditions at low temperatures. The mechanism of Ni2+ reduction and diffusion into SnS was observed in ethylene glycol, which served both as solvent and reducing agent. Tuning of reaction temperature and duration, morphology of the template SnS, and the application of ethylenediamine as supporting chelating agent, influence the formation of the final products. Their formation was controlled by carefully adjusting redox and equilibrium reactions. The products were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X‐ray spectroscopy analysis (EDX).
Size Effect of Graphene Oxide on Modulating Amyloid Peptide Assembly
Authors: Wang Jie , Cao Yunpeng , Li Qiang , Liu Lei , Dong Mingdong
Published: June 2015

Protein misfolding and abnormal assembly could lead to aggregates such as oligomer, proto‐fibril, mature fibril, and senior amyloid plaques, which are associated with the pathogenesis of many amyloid diseases. These irreversible amyloid aggregates typically form in vivo and researchers have been endeavoring to find new modulators to invert the aggregation propensity in vitro, which could increase understanding in the mechanism of the aggregation of amyloid protein and pave the way to potential clinical treatment. Graphene oxide (GO) was shown to be a good modulator, which could strongly control the amyloidosis of Aβ (33–42). In particular, quartz crystal microbalance (QCM), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM) measurements revealed the size‐dependent manner of GO on modulating the assembly of amyloid peptides, which could be a possible way to regulate the self‐assembled nanostructure of amyloid peptide in a predictable manner.
Enantioselective Arylation of N‐Tosylimines by Phenylboronic Acid Catalysed by a Rhodium/Diene Complex: Reaction Mechanism from Density Functional Theory
Authors: Sieffert Nicolas , Boisson Julien , Py Sandrine
Published: June 2015

A DFT study of the reaction mechanism of the rhodium‐catalysed enantioselective arylation of (E)‐N‐propylidene‐4‐methyl‐benzenesulfonamide by phenylboronic acid [Lin et al J. Am. Chem. Soc.­ 2011, 133, 12394] is reported. The catalyst ([{Rh(OH)(diene)}2]) includes a chiral diene ligand and the reaction is conducted in 1,4‐dioxane in the presence of drying agents (4 Å molecular sieves). Because phenylboronic acid is in equilibrium with phenylboroxin and water under the reaction conditions, three catalytic cycles are proposed that differ in the way the transmetallation and the release of the product are brought about, depending on the availability of phenylboronic acid, water and boroxin in the reaction medium. Based on computations, a new mechanism for the title reaction is proposed, in which phenylboronic acid plays the double role of “aryl source” and proton donor. This path does not require the presence of adventitious water molecules, in keeping with a reaction conducted in a dry medium. Comparisons with the generally accepted mechanism for arylation of enones proposed by Hayashi and co‐workers (J. Am. Chem. Soc.­ 2002, 124, 5052) show that the latter mechanism is less favourable and is not expected to operate in the case of the N‐tosylimine substrate considered herein. Finally, the possibility that phenylboroxin is the aryl source has also been investigated, but is not found to be competitive.
Evaluation of (4‐Arylpiperidin‐1‐yl)cyclopentanecarboxamides As High‐Affinity and Long‐Residence‐Time Antagonists for the CCR2 Receptor
Authors: Vilums Maris , Zweemer Annelien J. M. , Dilanchian Arian , van Veldhoven Jacobus P. D. , de Vries Henk , Brussee Johannes , Saunders John , Stamos Dean , Heitman Laura H. , IJzerman Adriaan P.
Published: June 2015

Animal models suggest that the chemokine ligand 2/CC‐chemokine receptor 2 (CCL2/CCR2) axis plays an important role in the development of inflammatory diseases. However, CCR2 antagonists have failed in clinical trials because of a lack of efficacy. We previously described a new approach for the design of CCR2 antagonists by the use of structure–kinetics relationships (SKRs). Herein we report new findings on the structure–affinity relationships (SARs) and SKRs of the reference compound MK‐0483, its diastereomers, and its structural analogues as CCR2 antagonists. The SARs of the 4‐arylpiperidine group suggest that lipophilic hydrogen‐bond‐accepting substituents at the 3‐position are favorable. However, the SKRs suggest that a lipophilic group with a certain size is desired [e.g., 3‐Br: Ki=2.8 nM, residence time (tres)=243 min; 3‐iPr: Ki=3.6 nM, tres=266 min]. Alternatively, additional substituents and further optimization of the molecule, while keeping a carboxylic acid at the 3‐position, can also prolong tres; this was most prominently observed in MK‐0483 (Ki=1.2 nM, tres=724 min) and a close analogue (Ki=7.8 nM) with a short residence time.
Target Fishing by Cross‐Docking to Explain Polypharmacological Effects
Authors: Patel Hitesh , Lucas Xavier , Bendik Igor , Günther Stefan , Merfort Irmgard
Published: June 2015

Drugs may have polypharmacological phenomena, that is, in addition to the desired target, they may also bind to many undesired or unknown physiological targets. As a result, they often exert side effects. In some cases, off‐target interactions may lead to drug repositioning or to explaining a drug’s mode of action. Herein we present an in silico approach for target fishing by cross‐docking as a method to identify new drug–protein interactions. As an example and proof of concept, this method predicted the peroxisome proliferator‐activated receptor (PPAR)‐γ as a target of ethacrynic acid, which may explain the hyperglycemic effect brought on by this molecule. The antagonistic effect of ethacrynic acid on PPAR‐γ was validated in a transient transactivation assay using human HEK293 cells. The cross‐docking approach also predicted the potential mechanisms of many other drug side effects and discloses new drug repositioning opportunities. These putative interactions are described herein, and can be readily used to discover therapeutically relevant drug effects.
Binding Mode of Acetylated Histones to Bromodomains: Variations on a Common Motif
Authors: Marchand Jean‐Rémy , Caflisch Amedeo
Published: June 2015

Bromodomains, epigenetic readers that recognize acetylated lysine residues in histone tails, are potential drug targets in cancer and inflammation. Herein we review the crystal structures of human bromodomains in complex with histone tails and analyze the main interaction motifs. The histone backbone is extended and occupies, in one of the two possible orientations, the bromodomain surface groove lined by the ZA and BC loops. The acetyl‐lysine side chain is buried in the cavity between the four helices of the bromodomain, and its oxygen atom accepts hydrogen bonds from a structural water molecule and a conserved asparagine residue in the BC loop. In stark contrast to this common binding motif, a large variety of ancillary interactions emerge from our analysis. In 10 of 26 structures, a basic side chain (up to five residues up‐ or downstream in sequence with respect to the acetyl‐lysine) interacts with the carbonyl groups of the C‐terminal turn of helix αB. Furthermore, the complexes reveal many heterogeneous backbone hydrogen bonds (direct or water‐bridged). These interactions contribute unselectively to the binding of acetylated histone tails to bromodomains, which provides further evidence that specific recognition is modulated by combinations of multiple histone modifications and multiple modules of the proteins involved in transcription.
Superparamagnetic iron oxide nanoparticles as a means to track mesenchymal stem cells in a large animal model of tendon injury
Authors: Scharf Alexandra , Holmes Shannon , Thoresen Merrilee , Mumaw Jennifer , Stumpf Alaina , Peroni John
Published: June 2015

The goal of this study was to establish an SPIO‐based cell‐tracking method in an ovine model of tendonitis and to determine if this method may be useful for further study of cellular therapies in tendonitis in vivo. Functional assays were performed on labeled and unlabeled cells to ensure that no significant changes were induced by intracellular SPIOs. Following biosafety validation, tendon lesions were mechanically (n = 4) or chemically (n = 4) induced in four sheep and scanned ex vivo at 7 and 14 days to determine the presence and distribution of intralesional cells. Ovine MSCs labeled with 50 µg SPIOs/mL remained viable, proliferate, and undergo tri‐lineage differentiation (p < 0.05). Labeled ovine MSCs remained detectable in vitro in concentrated cell numbers as low as 10 000 and in volumetric distributions as low as 100 000 cells/mL. Cells remained detectable by MRI at 7 days, as confirmed by correlative histology for dually labeled SPIO+/GFP+ cells. Histological evidence at 14 days suggested that SPIO particles remained embedded in tissue, providing MRI signal, although cells were no longer present. SPIO labeling has proven to be an effective method for cell tracking for a large animal model of tendon injury for up to 7 days post‐injection. The data obtained in this study justify further investigation into the effects of MSC survival and migration on overall tendon healing and tissue regeneration. Copyright © 2015 John Wiley & Sons, Ltd.
Fluorescence Dynamics of Monocyclodextrin– and Bis(thiol‐cyclodextrin)–Coumarin C153 Complexes
Authors: Trencanova Marianna Gregova , Jane Eduard , Szocs Vojtech , Halaszova Sona , Jerigova Monika , Haizer Ludovit , Velic Dusan
Published: June 2015

The solvation and confinement of coumarin C153 within supramolecular host/guest complexes based on β‐cyclodextrin (β‐CD) and 6‐deoxy‐6‐thio‐β‐cyclodextrin (β‐CD‐SH) in water are studied by fluorescence spectroscopy. For β‐CD/C153, the 1:1 complex is proposed, and for β‐CD‐SH/C153 both the 1:1 and 2:1 complexes are believed to be formed. The 2:1 β‐CD‐SH/C153 complex has an association constant of 4.2×105 M−1 and a C153 population of 82 %, which are interestingly high values, indicating that the proposed β‐CD‐SH dimers structure are connected by covalent disulfide bonds; this is supported by mass spectrometry. Solvation related to fast hydrogen‐bond rearrangement as a part of fluorescence relaxation is determined by the ultrafast components of time‐resolved spectroscopy to be 3 and 7 ps for the 1:1 β‐CD/C153 and 2:1 β‐CD‐SH/C153 complexes, respectively.
Optimal control of a single‐phase H‐bridge DC–AC inverter
Authors: Miladi Yosra , Feki Moez , Derbel Nabil
Published: June 2015

The control of switched power converters has been mostly accomplished using pulse width modulation (PWM). Under this type of control, it has been shown in literature that DC–AC current mode single‐phase inverter may exhibit chaotic behavior if the proportional controller of the PWM modulator is badly tuned. In this work, we present a novel method to control the inverter using an optimal control approach. Our method consists in defining the switching instances in order to achieve the reference current with minimum error. To illustrate the efficiency of our proposed method, numerical simulations and comparison with the proportional and integral controller as well as to the proportional and resonant controller are presented. Copyright © 2015 John Wiley & Sons, Ltd.
Experience‐dependent plasticity of dendritic spines of layer 2/3 pyramidal neurons in the mouse cortex
Authors: Ma Lei , Qiao Qian , Tsai Jin‐Wu , Yang Guang , Li Wei , Gan Wen‐Biao
Published: June 2015

Previous studies have shown that sensory and motor experiences play an important role in the remodeling of dendritic spines of layer 5 (L5) pyramidal neurons in the cortex. In this study, we examined the effects of sensory deprivation and motor learning on dendritic spine remodeling of layer 2/3 (L2/3) pyramidal neurons in the barrel and motor cortices. Similar to L5 pyramidal neurons, spines on apical dendrites of L2/3 pyramidal neurons are plastic during development and largely stable in adulthood. Sensory deprivation via whisker trimming reduces the elimination rate of existing spines without significant effect on the rate of spine formation in the developing barrel cortex. Furthermore, we show that motor training increases the formation and elimination of dendritic spines in the primary motor cortex. Unlike L5 pyramidal neurons, however, there is no significant difference in the rate of spine formation between sibling dendritic branches of L2/3 pyramidal neurons. Our studies indicate that sensory and motor learning experiences have important impact on dendritic spine remodeling in L2/3 pyramidal neurons. They also suggest that the rules governing experience‐dependent spine remodeling are largely similar, but not identical, between L2/3 and L5 pyramidal neurons. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 277–286, 2016
Isolation and characterization of a newly identified impurity in methamphetamine synthesized via reductive amination of 1‐phenyl‐2‐propanone (P2P) made from phenylacetic acid/lead (II) acetate
Authors: Toske Steven G. , McConnell Jennifer B. , Brown Jaclyn L. , Tuten Jennifer M. , Miller Erin E. , Phillips Monica Z. , Vazquez Etienne R. , Lurie Ira S. , Hays Patrick A. , Guest Elizabeth M.
Published: June 2015

A trace processing impurity found in certain methamphetamine exhibits was isolated and identified as trans‐N‐methyl‐4‐methyl‐5‐phenyl‐4‐penten‐2‐amine hydrochloride (1). It was determined that this impurity was produced via reductive amination of trans‐4‐methyl‐5‐phenyl‐4‐penten‐2‐one (4), which was one of a cluster of related ketones generated during the synthesis of 1‐phenyl‐2‐propanone (P2P) from phenylacetic acid and lead (II) acetate. This two‐step sequence resulted in methamphetamine containing elevated levels of 1. In contrast, methamphetamine produced from P2P made by other methods produced insignificant (ultra‐trace or undetectable) amounts of 1. These results confirm that 1 is a synthetic marker compound for the phenylacetic acid and lead (II) acetate method. Analytical data for 1 and 4, and a postulated mechanism for the production of 4, are presented. Copyright © 2015 John Wiley & Sons, Ltd.
Exploring seascape genetics and kinship in the reef sponge Stylissa carteri in the Red Sea
Authors: Giles Emily C. , Saenz‐Agudelo Pablo , Hussey Nigel E. , Ravasi Timothy , Berumen Michael L.
Published: June 2015

A main goal of population geneticists is to study patterns of gene flow to gain a better understanding of the population structure in a given organism. To date most efforts have been focused on studying gene flow at either broad scales to identify barriers to gene flow and isolation by distance or at fine spatial scales in order to gain inferences regarding reproduction and local dispersal. Few studies have measured connectivity at multiple spatial scales and have utilized novel tools to test the influence of both environment and geography on shaping gene flow in an organism. Here a seascape genetics approach was used to gain insight regarding geographic and ecological barriers to gene flow of a common reef sponge, Stylissa carteri in the Red Sea. Furthermore, a small‐scale (<1 km) analysis was also conducted to infer reproductive potential in this organism. At the broad scale, we found that sponge connectivity is not structured by geography alone, but rather, genetic isolation in the southern Red Sea correlates strongly with environmental heterogeneity. At the scale of a 50‐m transect, spatial autocorrelation analyses and estimates of full‐siblings revealed that there is no deviation from random mating. However, at slightly larger scales (100–200 m) encompassing multiple transects at a given site, a greater proportion of full‐siblings was found within sites versus among sites in a given location suggesting that mating and/or dispersal are constrained to some extent at this spatial scale. This study adds to the growing body of literature suggesting that environmental and ecological variables play a major role in the genetic structure of marine invertebrate populations.
Evaluation of habitat suitability index models by global sensitivity and uncertainty analyses: a case study for submerged aquatic vegetation
Authors: Zajac Zuzanna , Stith Bradley , Bowling Andrea C. , Langtimm Catherine A. , Swain Eric D.
Published: June 2015

Habitat suitability index (HSI) models are commonly used to predict habitat quality and species distributions and are used to develop biological surveys, assess reserve and management priorities, and anticipate possible change under different management or climate change scenarios. Important management decisions may be based on model results, often without a clear understanding of the level of uncertainty associated with model outputs. We present an integrated methodology to assess the propagation of uncertainty from both inputs and structure of the HSI models on model outputs (uncertainty analysis: UA) and relative importance of uncertain model inputs and their interactions on the model output uncertainty (global sensitivity analysis: GSA). We illustrate the GSA/UA framework using simulated hydrology input data from a hydrodynamic model representing sea level changes and HSI models for two species of submerged aquatic vegetation (SAV) in southwest Everglades National Park: Vallisneria americana (tape grass) and Halodule wrightii (shoal grass). We found considerable spatial variation in uncertainty for both species, but distributions of HSI scores still allowed discrimination of sites with good versus poor conditions. Ranking of input parameter sensitivities also varied spatially for both species, with high habitat quality sites showing higher sensitivity to different parameters than low‐quality sites. HSI models may be especially useful when species distribution data are unavailable, providing means of exploiting widely available environmental datasets to model past, current, and future habitat conditions. The GSA/UA approach provides a general method for better understanding HSI model dynamics, the spatial and temporal variation in uncertainties, and the parameters that contribute most to model uncertainty. Including an uncertainty and sensitivity analysis in modeling efforts as part of the decision‐making framework will result in better‐informed, more robust decisions.
Host‐associated differentiation in a highly polyphagous, sexually reproducing insect herbivore
Authors: Antwi Josephine B. , Sword Gregory A. , Medina Raul F.
Published: June 2015

Insect herbivores may undergo genetic divergence on their host plants through host‐associated differentiation (HAD). Much of what we know about HAD involves insect species with narrow host ranges (i.e., specialists) that spend part or all their life cycle inside their hosts, and/or reproduce asexually (e.g., parthenogenetic insects), all of which are thought to facilitate HAD. However, sexually reproducing polyphagous insects can also exhibit HAD. Few sexually reproducing insects have been tested for HAD, and when they have insects from only a handful of potential host‐plant populations have been tested, making it difficult to predict how common HAD is when one considers the entire species' host range. This question is particularly relevant when considering insect pests, as host‐associated populations may differ in traits relevant to their control. Here, we tested for HAD in a cotton (Gossypium hirsutum) pest, the cotton fleahopper (CFH) (Pseudatomoscelis seriatus), a sexually reproducing, highly polyphagous hemipteran insect. A previous study detected one incidence of HAD among three of its host plants. We used Amplified fragment length polymorphism (AFLP) markers to assess HAD in CFH collected from an expanded array of 13 host‐plant species belonging to seven families. Overall, four genetically distinct populations were found. One genetically distinct genotype was exclusively associated with one of the host‐plant species while the other three were observed across more than one host‐plant species. The relatively low degree of HAD in CFH compared to the pea aphid, another hemipteran insect, stresses the likely importance of sexual recombination as a factor increasing the likelihood of HAD.
Group 3 innate lymphoid cells (ILC3s): Origin, differentiation, and plasticity in humans and mice
Authors: Montaldo Elisa , Juelke Kerstin , Romagnani Chiara
Published: June 2015

Since their discovery, innate lymphoid cells (ILCs) have been the subject of intense research. As their name implies, ILCs are innate cells of lymphoid origin, and can be grouped into subsets based on their cytotoxic activity, cytokine profile, and the transcriptional requirements during ILC differentiation. The main ILC groups are “killer” ILCs, comprising NK cells, and “helper‐like” ILCs (including ILC1s, ILC2s, and ILC3s). This review examines the origin, differentiation stages, and plasticity of murine and human ILC3s. ILC3s express the retinoic acid receptor (RAR) related orphan receptor RORγt and the signature cytokines IL‐22 and IL‐17. Fetal ILC3s or lymphoid tissue inducer cells are required for lymphoid organogenesis, while postnatally developing ILC3s are important for the generation of intestinal cryptopatches and isolated lymphoid follicles as well as for the defence against pathogens and epithelial homeostasis. Here, we discuss the transcription factors and exogenous signals (including cytokines, nutrients and cell‐to‐cell interaction) that drive ILC3 lineage commitment and acquisition of their distinctive effector program.
Printed interdigital electrodes on plastic film for tumor cells density monitoring
Authors: Chen Liang , Guo Jinhong
Published: June 2015

Printed sensor has been introduced as a rapid and cost‐effective platform for biomedical applications, especially for wearable biosensing and point‐of‐care diagnosis. In this paper, we reported a tumor cell density monitoring device with printed interdigital electrodes on a plastic film. Numerical simulation of electrical impedance spectroscopy shows good agreement with the experimental measurement of DI water and PBS solution. Different concentrations of cancer cells were used to demonstrate the capability of cell culture monitoring. The developed device is highly cost‐effective and easy for fabrication, which may have great potentials in low‐cost analysis of biological cells. In a word, this paper shows a more rapid and simple cell counting method as compared to tedious microscope cell counting.
Amperometric detection in the presence of carbon nanotubes dispersed in background electrolyte: Evaluating its suitability for capillary electrokinetic chromatography separations of polyphenolic compounds
Authors: Moreno Mónica , Sánchez Arribas Alberto , Bermejo Esperanza , Zapardiel Antonio , Chicharro Manuel
Published: June 2015

This work reports on the positive effects observed upon both the separation and analytical signals in electrophoretic separations of selected phenolic compounds when using aqueous BGE containing carbon nanotubes (CNTs) in connection to electrochemical detection (ECD). The influence of the presence of surfactant‐coated CNTs in the BGE upon the amperometric response of probe compounds was evaluated under hydrodynamic regime in capillary flow injection experiments as well as electrophoretic separations. Among the surfactants employed to disperse CNTs within BGE, SDS shows the best results in terms of dispersion stability and degree of dispersion of the CNTs. ECD allows working with BGEs containing CNTs concentrations of, at least, 24.0 mg/L without increasing of baseline noise, on the opposite to that reported when using UV‐visible detection, and the presence of CNTs in the BGE improves the electrochemical response of some of the tested compounds. These benefits were reflected in higher sensibility in the electrochemical signal and additional improved resolution in the electrophoretic separation of (±)‐catechin and sinapic acid when using these BGE containing CNTs.
Platinum electrode modification: Unique surface carbonization approach to improve performance and sensitivity
Authors: Lee Hwi Yong , Barber Cedrick , Minerick Adrienne R.
Published: June 2015

Many microfluidic devices, also known as lab‐on‐a‐chip devices, employ electrochemical detection methods using microelectrodes. Miniaturizing electrodes inevitably reduces electrode sensitivity and decreases the S/N, which limits applications within microfluidic devices. However, microelectrode surface modification can increase the surface area and sensitivity. In the present work, we report substantial improvement in platinum electrode performance and sensitivity by coating with carbon from red blood cells. The larger goal of this work was to measure DC electrical resistances of red blood cell suspensions in a microchannel for hematocrit determination. It was observed that as current responses of red blood cell suspensions were measured, the platinum electrode performance (reproducibility and S/N) improved with time. The platinum electrode electrocatalytic activity for red blood cell current measurements improved by 140%. Systematic experimentation revealed that red blood cells adsorb and carbonize the platinum electrode surfaces. The electrode surfaces before and after performance improvements were analyzed by field emission scanning electron microscopy, energy dispersive spectrometry, and Raman spectrometry. The formed carbon layers on the electrode surfaces were found to be proteomic and increased surface area with a porous three‐dimensional structure, thus improving performance and stabilizing currents.
Partition behavior of hydrophilic diols in an ethanol/ammonium sulfate salting‐out extraction system
Authors: Fu Hongxin , Dai Jianying , Sun Yaqin , Zhang Daijia , Xiu Zhilong
Published: June 2015

It is important to investigate the partition behavior of hydrophilic alcohols at different process parameters in order to have a deep understanding of the salting‐out extraction technique and to design suitable downstream processes. First, phase diagram data of ethanol/ammonium sulfate at 293.15 K were obtained, and the reliability of binodal curve and tie line data were proved by Merchuk, Othmer–Tobias, and Bancroft equations, respectively. Then, the partition behavior of five short‐chain diols was studied. For different tie lines, the partition coefficient changed linearly with an increase in tie line length. The concentration of diols also had a significant effect on the partition behavior due to the similarity between diols and ethanol. Further, the effect of temperature was increased as the hydrophobicity of the diols increased, and the partition behavior of diols was correlated with their hydrophobicity, implying that the solutes with higher hydrophobicity could be extracted more effectively. These findings are useful for designing an economic and efficient salting‐out extraction process for diverse products.
CD48‐deficient T‐lymphocytes from DMBA‐treated rats have de novo mutations in the endogenous Pig‐a gene
Authors: Dobrovolsky Vasily N. , Revollo Javier , Pearce Mason G. , Pacheco‐Martinez M. Monserrat , Lin Haixia
Published: June 2015

A major question concerning the scientific and regulatory acceptance of the rodent red blood cell‐based Pig‐a gene mutation assay is the extent to which mutants identified by their phenotype in the assay are caused by mutations in the Pig‐a gene. In this study, we identified T‐lymphocytes deficient for the glycosylphosphatidylinositol‐anchored surface marker, CD48, in control and 7,12‐dimethylbenz[a]anthracene (DMBA)‐treated rats using a flow cytometric assay and determined the spectra of mutations in the endogenous Pig‐a gene in these cells. CD48‐deficient T‐cells were seeded by sorting at one cell per well into 96‐well plates, expanded into clones, and exons of their genomic Pig‐a were sequenced. The majority (78%) of CD48‐deficient T‐cell clones from DMBA‐treated rats had mutations in the Pig‐a gene. The spectrum of DMBA‐induced Pig‐a mutations was dominated by mutations at A:T, with the mutated A being on the nontranscribed strand and A→T transversion being the most frequent change. The spectrum of Pig‐a mutations in DMBA‐treated rats was different from the spectrum of Pig‐a mutations in N‐ethyl‐N‐nitrosourea (ENU)‐treated rats, but similar to the spectrum of DMBA mutations for another endogenous X‐linked gene, Hprt. Only 15% of CD48‐deficient mutants from control animals contained Pig‐a mutations; T‐cell biology may be responsible for a relatively large fraction of false Pig‐a mutant lymphocytes in control animals. Among the verified mutants from control rats, the most common were frameshifts and deletions. The differences in the spectra of spontaneous, DMBA‐, and ENU‐induced Pig‐a mutations suggest that the flow cytometric Pig‐a assay detects de novo mutation in the endogenous Pig‐a gene. Environ. Mol. Mutagen. 56:674–683, 2015. © 2015 Wiley Periodicals, Inc.
MRP1 expression in bronchoalveolar lavage cells in subjects with lung cancer who were chronically exposed to arsenic
Authors: Recio‐Vega Rogelio , Dena‐Cazares Jose Angel , Ramirez‐de la Peña Jorge Luis , Jacobo‐Ávila Antonio , Portales‐Castanedo Arnulfo , Gallegos‐Arreola Martha Patricia , Ocampo‐Gomez Guadalupe , Michel‐Ramirez Gladis
Published: June 2015

Alteration of multidrug resistance‐associated protein‐1 (MRP1) expression has been associated with certain lung diseases, and this protein may be pivotal in protecting the lungs against endogenous or exogenous toxic compounds. The aim of this study was to evaluate and compare the expression of MRP1 in bronchoalveolar cells from subjects with and without lung cancer who had been chronically exposed to arsenic through drinking water. MRP1 expression was assessed in bronchoalveolar cells in a total of 102 participants. MRP1 expression was significantly decreased in those with arsenic urinary levels >50 μg/L when compared with the controls. In conclusion, chronic arsenic exposure negatively correlates with the expression of MRP1 in BAL cells in patients with lung cancer. Environ. Mol. Mutagen. 56:759–766, 2015. © 2015 Wiley Periodicals, Inc.
Catalytic and non‐catalytic roles of DNA polymerase κ in the protection of human cells against genotoxic stresses
Authors: Kanemaru Yuki , Suzuki Tetsuya , Niimi Naoko , Grúz Petr , Matsumoto Kyomu , Adachi Noritaka , Honma Masamitsu , Nohmi Takehiko
Published: June 2015

DNA polymerase κ (Pol κ) is a specialized DNA polymerase involved in translesion DNA synthesis. Although its bypass activities across lesions are well characterized in biochemistry, its cellular protective roles against genotoxic insults are still elusive. To better understand the in vivo protective roles, we have established a human cell line deficient in the expression of Pol κ (KO) and another expressing catalytically dead Pol κ (CD), to examine the cytotoxic sensitivity to 11 genotoxins including ultraviolet C light (UV). These cell lines were established in a genetic background of Nalm‐6‐MSH+, a human lymphoblastic cell line that has high efficiency for gene targeting, and functional p53 and mismatch repair activities. We classified the genotoxins into four groups. Group 1 includes benzo[a]pyrene diolepoxide, mitomycin C, and bleomycin, where the sensitivity was equally higher in KO and CD than in the cell line expressing wild‐type Pol κ (WT). Group 2 includes hydrogen peroxide and menadione, where hypersensitivity was observed only in KO. Group 3 includes methyl methanesulfonate and ethyl methanesulfonate, where hypersensitivity was observed only in CD. Group 4 includes UV and three chemicals, where the chemicals exhibited similar cytotoxicity to all three cell lines. The results suggest that Pol κ not only protects cells from genotoxic DNA lesions via DNA polymerase activities, but also contributes to genome integrity by acting as a non‐catalytic protein against oxidative damage caused by hydrogen peroxide and menadione. The non‐catalytic roles of Pol κ in protection against oxidative damage by hydrogen peroxide are discussed. Environ. Mol. Mutagen. 56:650–662, 2015. © 2015 Wiley Periodicals, Inc.
A temporal compressive resource allocation technique for complexity reduction in PLC transceivers
Authors: Colen Guilherme R. , Schettino Hugo , Fernandes Diogo , Sirimarco Lucas M. , de Campos Fabrício P. V. , Finamore Weiler A. , Latchman Haniph A. , Ribeiro Moises V.
Published: June 2015

This work introduces a novel resource allocation technique for dealing with linear and periodically time‐varying power line channels when an orthogonal frequency division multiplexing scheme is applied. By exploiting the correlations within one cycle of the mains signal, among cycles of mains signal and a combination of these connections, the proposed technique can offer three distinct trade‐offs between computational complexity reduction and data‐rate loss. Numerical results, which are based on measured data, are used to analyse these trade‐offs, when these inter‐cycle and intra‐cycle relationship are taken into account. Also, we verify that the use of the normalised signal‐to‐noise ratio incurs very low performance degradation, and because of computational complexity rationale, its use is strongly recommended. Additionally, we show that those cases, in which the correlations among the cycles of the mains signal is relevant, offer the best trade‐off between computational complexity reduction and data‐rate loss. Finally, we show that the proposed technique can achieve the optimal data‐rate and offers substantial improvements in terms of computational complexity when compared with existing approaches, including the Institute of Electrical and Electronics Engineers 1901 standard. Copyright © 2015 John Wiley & Sons, Ltd.
Structure–odour relationships reviewed in the postgenomic era
Authors: de March Claire A. , Ryu SangEun , Sicard Gilles , Moon Cheil , Golebiowski Jérôme
Published: June 2015

This review reports on the knowledge about odourant–olfactory receptor interactions and their projection within the field of structure–odour relationships (SOR). We provide a list of agonists and odour spaces associated with deorphanized human olfactory receptors. The link between olfactory receptor responses, differential perception and subtleties within odour families is discussed. Copyright © 2015 John Wiley & Sons, Ltd.
The simulation of turbulent particle‐laden channel flow by the Lattice Boltzmann method
Authors: Banari Amir , Mauzole Yackar , Hara Tetsu , Grilli Stephan T. , Janßen Christian F.
Published: June 2015

We perform direct numerical simulation of three‐dimensional turbulent flows in a rectangular channel, with a lattice Boltzmann method, efficiently implemented on heavily parallel general purpose graphical processor units. After validating the method for a single fluid, for standard boundary layer problems, we study changes in mean and turbulent properties of particle‐laden flows, as a function of particle size and concentration. The problem of physical interest for this application is the effect of water droplets on the turbulent properties of a high‐speed air flow, near a solid surface. To do so, we use a Lagrangian tracking approach for a large number of rigid spherical point particles, whose motion is forced by drag forces caused by the fluid flow; particle effects on the latter are in turn represented by distributed volume forces in the lattice Boltzmann method. Results suggest that, while mean flow properties are only slightly affected, unless a very large concentration of particles is used, the turbulent vortices present near the boundary are significantly damped and broken down by the turbulent motion of the heavy particles, and both turbulent Reynolds stresses and the production of turbulent kinetic energy are decreased because of the particle effects. We also find that the streamwise component of turbulent velocity fluctuations is increased, while the spanwise and wall‐normal components are decreased, as compared with the single fluid channel case. Additionally, the streamwise velocity of the carrier (air) phase is slightly reduced in the logarithmic boundary layer near the solid walls. Copyright © 2015 John Wiley & Sons, Ltd.
Influence of spatial discretization and unsteadiness on the simulation of rocket combustors
Authors: Lempke Markus , Keller Roman , Gerlinger Peter
Published: June 2015

This paper investigates some important numerical aspects for the simulation of model rocket combustors. Precisely, (1) a new high‐order discretization technique (multi‐dimensional limiting process (MLP), low diffusion, and MLPld) is presented and compared with conventional second‐order schemes with different flux limiters. (2) Time accurate unsteady Reynolds‐averaged Navier–Stokes (RANS) simulations are performed to assess possible improvements in comparison with steady‐state RANS simulations. (3) Fully 3D simulations of an axisymmetric rocket combustor are compared with 2D axisymmetric ones. All studies are based on the Penn State preburner combustor experiment, which uses gaseous oxygen and hydrogen. This comprehensive study offers unique insight into how the mentioned numerical influence factors change the flow field, flame, and wall heat fluxes in the model rocket combustor. Because wall heat fluxes are known from the experiment only, numerical results are compared with LES of other authors, too. It will be shown that the high‐order spatial discretization significantly improves the agreement with measured wall heat fluxes at low additional computational cost. In general the transition from simple to more complex numerical approaches steadily improves the qualitative agreement between simulation and experiment. Copyright © 2015 John Wiley & Sons, Ltd.
Factors with an influence on the wear to excavation tools in hydroshield tunnelling in soft ground / Einflussfaktoren auf den Verschleiß der Abbauwerkzeuge beim Vortrieb mit Hydroschild‐TVM in Lockergesteinen
Authors: Köppl Florian , Thuro Kurosch , Thewes Markus
Published: June 2015

The wear to excavation tools is a central challenge for tunnelling with Hydroshield (TBM) in soft ground because it is one of the main causes of stoppages. Due to the inaccessibility of the processes involved and the wide range of influencing factors, there has been no method of forecasting the wear to excavation tools until now. Working from a detailed analysis of 18 tunnel drives with hydroshield TBMs, an empirical approach to investigate the factors with an influence on the wear to excavation tools was selected for the present work. The analysis enables the qualification and quantification of the essential factors with an influence on the tool life parameters of the excavation tools.

Der Verschleiß der Abbauwerkzeuge ist eine zentrale Herausforderung beim Vortrieb mit Hydroschild‐TVM in Lockergesteinen, weil dieser eine Hauptursache für Vortriebsunterbrechungen ist. Bisher liegen aufgrund der Unzugänglichkeit der beteiligten Prozesse und der hohen Bandbreite an Einflussfaktoren keine Prognosemethoden für den Verschleiß der Abbauwerkzeuge vor. Mit der detaillierten Analyse von 18 Vortrieben mit Hydroschild‐TVM wurde für die vorliegende Arbeit ein empirischer Ansatz zur Untersuchung der Einflussfaktoren auf den Verschleiß der Abbauwerkzeuge gewählt. Die Analyse erlaubt die Qualifizierung und Quantifizierung der maßgeblichen Einflussfaktoren auf die Standgrößen der Abbauwerkzeuge.
Strain gauges in pre‐cast concrete segments: working principle, evaluation and interpretation / Dehnmessgeber in Tübbingsegmenten – Funktionsweise, Auswertung und Interpretation
Authors: Radončić Nedim , Kern Martin , Weissnar Martin , Moritz Bernd
Published: June 2015

In order to obtain an enhanced understanding of the system behaviour, especially with regard to the capacity reserves of the support and general load conditions, measurement pre‐cast concrete rings are used at the ÖBB construction lot KAT2 of the Koralm Tunnel. These are equipped with a strain gauge in each reinforcement layer, thus allowing direct measurement of the strains in every pre‐cast concrete segment.

Based on this information, the stress distribution in the respective segment cross‐section can be calculated, allowing section forces determination by integrating them. The used interpolation method allows the presentation of the section forces over circumference of the entire ring based on the measurement data of each segment, while obeying the constraints by the issue of longitudinal joint capacity.

The applied calculation method is verified by comparing its results with a numerical 3D analysis. The application of the method is presented by a case study of the measurement ring installation at the ÖBB construction lot KAT2 of the Koralm Tunnel. In addition, further room for research and development is briefly outlined.

Um ein besseres Verständnis des Systemverhaltens – speziell im Hinblick auf die Auslastung des Ausbaus und der vorherrschenden Belastungssituation – zu erhalten, werden beim TVM‐Vortrieb auf dem Baulos Koralmtunnel 2 (KAT2) der ÖBB‐Infrastruktur AG Tübbingsegmente mit Dehnmessgebern, sogenannte Messtübbinge, verwendet. Diese sind mit Dehnmessgebern in beiden Bewehrungslagen, in denen die Dehnungen direkt gemessen werden, ausgestattet.

Anhand dieser Daten kann die Spannungsverteilung im jeweiligen Tübbingquerschnitt errechnet und in weiterer Folge können über Integration die Schnittkräfte ermittelt werden. Die verwendete Interpolationsmethode ermöglicht, unter Berücksichtigung der Längsfugenbelastbarkeit, die Darstellung der Schnittkräfte über den gesamten Umfang des Tübbingrings, ausgehend von den Ergebnissen an der jeweiligen Position der Dehnmessgeber.

Die angewandte Berechnungsmethode wird zur Verifizierung mit den Resultaten einer numerischen 3D‐Berechnung verglichen. Die Anwendung dieser Methodik wird anhand eines Fallbeispiels an einem Messtübbingring, der am Baulos KAT2 eingebaut wurde, vorgestellt. Zusätzlich wird noch kurz auf ausstehende Forschungsthemen und Entwicklungen eingegangen.
Wear and abrasivity: observations from EPB drives in mixed soft – rock sections
Authors: González Claudia , Arroyo Marcos , Gens Antonio
Published: June 2015

This paper summarizes the main observations related to geotechnical properties and tool changes that characterize the different tunnel drives in a database of 33 km of EPB tunnel records from the Barcelona area. The data have been examined in detail with regard to cutting tool replacement and performance of the mechanized excavation. The database includes tunnels in soft soils, in hard and medium rocks and in mixed soil‐rock conditions; tool changing records and geotechnical properties. Transverse and longitudinal geotechnical heterogeneity are accounted for systematically. Longitudinal heterogeneity is used to subdivide the drives in the database into homogeneous units. Transverse (within section) heterogeneity is described by a set of newly developed impact factors FI.
A simple approach based on the limit equilibrium method for evaluating passive earth pressure coefficients
Authors: Patki Mrunal A. , Mandal Jnanendra Nath , Dewaikar Dileep Moreshwar
Published: June 2015

A numerical method is developed for evaluating critical passive earth pressure coefficients Kpγ for the case of an inclined rigid retaining wall resting against sloping cohesionless backfill. The methodology of the proposed investigation is based on the limit equilibrium approach with the assumption of a complete log spiral failure mechanism. The Kpγ coefficients obtained from this study are compared with the existing theoretical and experimental results. The proposed Kpγ values are on a par with the best upper bound solution given by Soubra and Macuh using the limit analysis method. Further, the results presented here compare fairly well with those given by Kerisel and Absi, which establishes the validity of the proposed research work. Efforts are taken to present the design tables for a wide variety of soil properties, soil‐wall interface properties and geometrical properties of the wall and the backfill.

Ein einfacher Ansatz zur Bestimmung von Erdwiderstandsbeiwerten auf Basis der Methode des Grenzgleichwichts. Eine numerische Methode zur Bestimmung des kritischen Erdwiderstandsbeiwerts Kpγ wird entwickelt für den Fall einer geneigten, steifen Verbauwand vor geböschtem, kohäsionslosem Erdreich. Die Methodik der vorgeschlagenen Untersuchung basiert dabei auf dem Ansatz des Grenzgleichgewichts unter Annahme eines Versagensmechanismus mit logarithmischer Spiralform. Der mittels dieser Studie bestimmte Kpγ‐Beiwert wird mit vorhandenen theoretischen und experimentellen Ergebnissen verglichen. Es wird gezeigt, dass die vorgeschlagenen Werte für Kpγ den Werten der besten Lösung unter Verwendung des Obere‐Schranken‐Theorems nach Soubra und Macuh entsprechen, welche mit Hilfe einer Grenzwertanalyse ermittelt wurde. Darüber hinaus stimmen die hier präsentierten Ergebnisse gut mit denen von Kerisel und Absi überein, was die Gültigkeit der vorgeschlagenen Vorgehensweise belegt. Bemessungstafeln für eine große Anzahl an Bodenparametern, Boden‐Wand‐Interface Parametern und geometrischen Parametern der Wand sowie des abzustützenden Erdreichs werden eingeführt.