bluuebunny/crossref_metadata_2025 huggingface dataset:
Architectural and Surface Modification of Nanofibrous Scaffolds for Tissue Engineering
Authors: Pettikiriarachchi Jerani T.S. , Parish Clare L. , Nisbet David R. , Forsythe John S.
Published: February 2012

The sections in this article are

Introduction

Tissue Engineering Scaffolds

Nanofibrous Scaffolds

Electrospinning

Cellular Interactions with Polymeric Nanofibers

Optimizing Fiber and Scaffold Architecture

Fiber Diameter

Fiber Orientation

Core–Shell Fibers

Pore Size

Layering Fibers

Optimizing the Fiber Surface

Polymer Blending

Coating Fibers

Chemical Modification of Fibers

Polymer Grafting onto Surfaces

Plasma Treatment of Fibers

Biomolecule Attachment

Challenges with Fibrous Scaffolds in Tissue Engineering

Future Perspectives
Physical and Relational Aggression in Early Adolescence: Associations with Narcissism, Temperament, and Social Goals
Authors: Ojanen Tiina , Findley Danielle , Fuller Sarah
Published: February 2012

This study examined adolescent narcissism, temperament (frustration and affiliation), and social goals in association with peer‐reported physical and relational aggression (N = 384; 12–14 years). Narcissism was positively associated with dominance goals and negatively with closeness goals for peer interaction. Moreover, narcissism was positively associated with physical aggression via dominance goals for boys, and with relational aggression via dominance goals for both genders. Temperamental frustration and affiliation were both positively associated with relational aggression, but also interacted in their associations with this variable; affiliation was positively associated with relational aggression only at high levels of frustration. Supporting and extending existing research, the present findings suggest that adolescent personality and social goals are meaningfully associated with physical and relational aggression in the peer context.
Is Adolescent Bullying an Evolutionary Adaptation?
Authors: Volk Anthony A. , Camilleri Joseph A. , Dane Andrew V. , Marini Zopito A.
Published: February 2012

Bullying appears to be ubiquitous across cultures, involving hundreds of millions of adolescents worldwide, and has potentially serious negative consequences for its participants (particularly victims). We challenge the traditionally held belief that bullying results from maladaptive development by reviewing evidence that bullying may be, in part, an evolved, facultative, adaptive strategy that offers some benefits to its practitioners. In support of this view, we draw from research that suggests bullying serves to promote adolescent bullies’ evolutionarily‐relevant somatic, sexual, and dominance goals, has a genetic basis, and is widespread among nonhuman animals. We identify and explain differences in the bullying behavior of the two sexes, as well as when and why bullying is adaptive and when it may not be. We offer commentary on both the failures and successes of current anti‐bullying interventions from an evolutionary perspective and suggest future directions for both research and anti‐bullying interventions. Aggr. Behav. 38:222–238, 2012. © 2012 Wiley Periodicals, Inc.
Synthesis of Interfacially Active and Magnetically Responsive Nanoparticles for Multiphase Separation Applications
Authors: Peng Junxia , Liu Qingxia , Xu Zhenghe , Masliyah Jacob
Published: February 2012

A novel interfacially active and magnetically responsive nanoparticle is designed and prepared by direct grafting of bromoesterified ethyl cellulose (EC‐Br) onto the surface of amino‐functionalized magnetite (Fe3O4) nanoparticles. Due to its strong interfacial activity, ethyl cellulose (EC) on the magnetic nanoparticles enables the EC‐grafted Fe3O4 (M‐EC) nanoparticles to be interfacially active. The grafting of interfacially active polymer EC on magnetic nanoparticles is confirmed by zeta‐potential measurements, diffuse reflectance infrared Fourier‐transform spectroscopic (DRIFTS) characterization, and thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) images show a negligible increase in particle size, confirming the thin silica coating and grafted EC layer. The magnetization measurements show a marginal reduction in saturation magnetization by silica coating and EC grafting of original magnetic nanoparticles, confirming the presence of coatings. The M‐EC nanoparticles prepared in this study show excellent interfacial activity and highly ordered features at the oil/water interface, as confirmed using the Langmuir–Blodgett technique and atomic force microscopy (AFM). The magnetic properties of M‐EC nanoparticles at the oil/water interface make the interfacial properties tunable by or responsive to an external magnetic field. The occupancy of M‐EC at the oil/water interface allows rapid separation of the water droplets from emulsions by an external magnetic field, demonstrating enhanced coalescence of magnetically tagged stable water droplets and a reduced overall volume fraction of the sludge.
High‐Density Hotspots Engineered by Naturally Piled‐Up Subwavelength Structures in Three‐Dimensional Copper Butterfly Wing Scales for Surface‐Enhanced Raman Scattering Detection
Authors: Tan Yongwen , Gu Jiajun , Xu Linhua , Zang Xining , Liu Dingxin , Zhang Wang , Liu Qinglei , Zhu Shenmin , Su Huilan , Feng Chuanliang , Fan Genlian , Zhang Di
Published: February 2012

Very recently, wing scales of natural Lepidopterans (butterflies and moths) manifested themselves in providing excellent three dimensional (3D) hierarchical structures for surface‐enhanced Raman scattering (SERS) detection. But the origin of the observed enormous Raman enhancement of the analytes on 3D metallic replicas of butterfly wing scales has not been clarified yet, hindering a full utilization of this huge natural wealth with more than 175 000 3D morphologies. Herein, the 3D sub‐micrometer Cu structures replicated from butterfly wing scales are successfully tuned by modifying the Cu deposition time. An optimized Cu plating process (10 min in Cu deposition) yields replicas with the best conformal morphologies of original wing scales and in turn the best SERS performance. Simulation results show that the so‐called “rib‐structures” in Cu butterfly wing scales present naturally piled‐up hotspots where electromagnetic fields are substantially amplified, giving rise to a much higher hotspot density than in plain 2D Cu structures. Such a mechanism is further verified in several Cu replicas of scales from various butterfly species. This finding paves the way to the optimal scale candidates out of ca. 175 000 Lepidopteran species as bio‐templates to replicate for SERS applications, and thus helps bring affordable SERS substrates as consumables with high sensitivity, high reproducibility, and low cost to ordinary laboratories across the world.
Nanostructured Ternary Electrodes for Energy‐Storage Applications
Authors: Rakhi Raghavan Baby , Chen Wei , Cha Dongkyu , Alshareef H. N.
Published: February 2012

A three‐component, flexible electrode is developed for supercapacitors over graphitized carbon fabric, utilizing γ‐MnO2 nanoflowers anchored onto carbon nanotubes (γ‐MnO2/CNT) as spacers for graphene nanosheets (GNs). The three‐component, composite electrode doubles the specific capacitance with respect to GN‐only electrodes, giving the highest‐reported specific capacitance (308 F g−1) for symmetric supercapacitors containing MnO2 and GNs using a two‐electrode configuration, at a scan rate of 20 mV s−1. A maximum energy density of 43 W h kg−1 is obtained for our symmetric supercapacitors at a constant discharge‐current density of 2.5 A g−1 using GN–(γ‐MnO2/CNT)‐nanocomposite electrodes. The fabricated supercapacitor device exhibits an excellent cycle life by retaining ≈90% of the initial specific capacitance after 5000 cycles.
Dental microwear texture and anthropoid diets
Authors: Scott Robert S. , Teaford Mark F. , Ungar Peter S.
Published: February 2012

Dental microwear has long been used as evidence concerning the diets of extinct species. Here, we present a comparative baseline series of dental microwear textures for a sample of 21 anthropoid primate species displaying interspecific and intraspecific dietary variability. Four dental microwear texture variables (complexity, anisotropy, textural fill volume, and heterogeneity) were computed based on scale‐sensitive fractal analysis and high‐resolution three‐dimensional renderings of microwear surfaces collected using a white‐light confocal profiler. The purpose of this analysis was to assess the extent to which these variables reflect variation in diet. Significant contrasts between species with diets known to include foods with differing material properties are clearly evident for all four microwear texture variables. In particular, species that consume more tough foods, such as leaves, tended to have high levels of anisotropy and low texture complexity. The converse was true for species including hard and brittle items in their diets either as staples or as fallback foods. These results reaffirm the utility of dental microwear texture analysis as an important tool in making dietary inferences based on fossil primate samples. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
A new method to estimate adult age‐at‐death using the acetabulum
Authors: Calce Stephanie E.
Published: February 2012

Rissech et al. (J Forensic Sci 51 (2006) 213–229) described a method to estimate age‐at‐death of adult males using seven traits of the fused acetabulum. This study simplifies Rissech et al.'s technique and extends its application to adult females. Rissech et al.'s original scoring method was applied to a sample of 100 known‐aged adults, three variables were selected based on stepwise multiple regression, and ages were collapsed into three broad ranges: young adult (17–39 years), middle adult (40–64 years), and old adult (65+ years). The revised method was applied to 249 new known‐aged individuals from two other samples. To minimize observer bias, highlight the most critical traits, and encompass more age‐related variation, unique digital renderings accompany morphological descriptions of age categories instead of photos. Three statistically significant characteristics highly correlated with age (P < 0.05) are capable of estimating age‐at‐death with 81% accuracy, both sexes combined. For misidentified individuals the tendency was to underestimate age. Results of both intraobserver error testing and inter‐rater reliability demonstrated a moderate to substantial agreement in scoring between observers. When estimating the degree of development of features osteophyte development of the acetabular rim was the most inconsistent between observers. The revised acetabular method shows promise in estimating age for adults, particularly for those over the age of 65 years. Am J Phys Anthropol 2012. © 2012 Wiley Periodicals, Inc.
Genetic variations and physical activity as determinants of limb bone morphology: An experimental approach using a mouse model
Authors: Wallace Ian J. , Tommasini Steven M. , Judex Stefan , Garland Theodore , Demes Brigitte
Published: February 2012

To gain insight into past human physical activity, anthropologists often infer functional loading history from the morphology of limb bone remains. It is assumed that, during life, loading had a positive, dose‐dependent effect on bone structure that can be identified despite other effects. Here, we investigate the effects of genetic background and functional loading on limb bones using mice from an artificial selection experiment for high levels of voluntary wheel running. Growing males from four replicate high runner (HR) lines and four replicate nonselected control (C) lines were either allowed or denied wheel access for 2 months. Using μCT, femoral morphology was assessed at two cortical sites (mid‐diaphysis, distal metaphysis) and one trabecular site (distal metaphysis). We found that genetic differences between the linetypes (HR vs. C), between the replicate lines within linetype, and between individuals with and without the so‐called “mini‐muscle” phenotype (caused by a Mendelian recessive gene that halves limb muscle mass) gave rise to significant variation in nearly all morphological indices examined. Wheel access also influenced femoral morphology, although the functional response did not generally result in enhanced structure. Exercise caused moderate periosteal enlargement, but relatively greater endocortical expansion, resulting in significantly thinner cortices and reduced bone area in the metaphysis. The magnitude of the response was independent of distance run. Mid‐diaphyseal bone area and area moments, and trabecular morphology, were unaffected by exercise. These results underscore the strong influence of genetics on bone structure and the complexity by which mechanical stimuli may cause alterations in it. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.
Incremental enamel development in modern human deciduous anterior teeth
Authors: Mahoney Patrick
Published: February 2012

This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204–214) to identify developmental differences along the tooth row. Two hypotheses are tested: Retzius line periodicity will remain constant in teeth from the same jaw and range from 6 to 12 days among individuals, as in human permanent teeth; daily enamel secretion rates (DSRs) will not vary between deciduous teeth, as in some human permanent tooth types. A further aim is to search for links between deciduous incremental enamel development and the previously reported eruptionsequence. Retzius line periodicity in anterior teeth ranged between 5 and 6 days, but did not differ between an incisor and molar of one individual. Intradian line periodicity was 12 h. Mean cuspal DSRs varied slightly between equivalent regions along the tooth row. Mandibular incisors initiated enamel formation first, had the fastest mean DSRs, the greatest prenatal formation time, and based upon prior studies are the first deciduous tooth to erupt. Relatively rapid development in mandibular incisors in advance of early eruption may explain some of the variation in DSRs along the tooth row that cannot be explained by birth. Links between DSRs, enamel initiation times, and the deciduous eruption sequence are proposed. Anterior crown formation times presented here can contribute toward human infant age‐at‐death estimates. Regression equations for reconstructing formation time in worn incisors are given. Am J Phys Anthropol 2012. © 2012 Wiley Periodicals, Inc.
Fitness‐related benefits of dominance in primates
Authors: Majolo B. , Lehmann J. , de Bortoli Vizioli A. , Schino G.
Published: February 2012

Dominance hierarchies are thought to provide various fitness‐related benefits to dominant individuals (e.g., preferential access to food or mating partners). Remarkably, however, different studies on this topic have produced contradictory results, with some showing strong positive association between rank and fitness (i.e., dominants gain benefits over subordinates), others weak associations, and some others even revealing negative associations. Here, we investigate dominance‐related benefits across primate species while controlling for phylogenetic effects. We extracted data from 94 published studies, representing 25 primate species (2 lemur species, 4 New World monkeys, 16 Old World monkeys, and 3 apes), to assess how dominance affects life‐history and behavior. We used standard and phylogenetic meta‐analyses to analyze the benefits of dominance in primates. Dominant females had higher infant survival to first year, although we found no significant effect of dominance on female feeding success. Results for female fecundity differed between the two meta‐analytical approaches, with no effect of dominance on female fecundity after controlling for phylogeny. Dominant males had a higher fecundity and mating success than subordinate males. Finally, the benefits of dominance for female fecundity were stronger in species with a longer lifespan. Our study supports the view that dominance hierarchies are a key aspect of primate societies as they indeed provide a number of fitness‐related benefits to individuals. Am J Phys Anthropol 2012. © 2012 Wiley Periodicals, Inc.
The Inherent Electrochemistry of Nickel/Nickel‐Oxide Nanoparticles
Authors: Giovanni Marcella , Ambrosi Adriano , Pumera Martin
Published: February 2012

The direct detection of nanoparticles is at the forefront of research owing to their environmental and toxicological applications. Herein, we studied the inherent electrochemistry of Ni and NiO nanoparticles and proposed a simple and direct electrochemical method for the determination of the concentrations of both nickel (Ni) and nickel oxide (NiO) nanoparticles in alkaline solution. A highly sensitive voltammetry technique was used to measure the oxidative signal of Ni(OH)2 that formed spontaneously on the surface of Ni and NiO nanoparticles in alkaline media. Detection limits of 220 μg mL−1 for Ni and 13 μg mL−1 for NiO nanoparticles were obtained. Ni and NiO nanoparticles are used as electrode modifiers or as electrochemical signal labels in various biosensing applications. Therefore, methods to rapidly quantify the amount of Ni and NiO nanoparticles are of widespread potential use.
Horizontal flows concurrent with an X2.2 flare in the active region NOAA 11158
Authors: Beauregard L. , Verma M. , Denker C.
Published: February 2012

Horizontal proper motions were measured with local correlation tracking (LCT) techniques in active region NOAA 11158 on 2011 February 15 at a time when a major (X2.2) solar flare occurred. The measurements are based on continuum images and magnetograms of the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. The observed shear flows along the polarity inversion line were rather weak (a few 100 m s–1). The counter‐streaming region shifted toward the north after the flare. A small circular area with flow speeds of up to 1.2 km s–1 appeared after the flare near a region of rapid penumbral decay. The LCT signal in this region was provided by small‐scale photospheric brigthenings, which were associated with fast traveling moving magnetic features. Umbral strengthening and rapid penumbral decay was observed after the flare. Both phenomena were closely tied to kernels of white‐light flare emission. The white‐light flare only lasted for about 15 min and peaked 4 min earlier than the X‐ray flux. In comparison to other major flares, the X2.2 flare in active region NOAA 11158 only produced diminutive photospheric signatures (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of the negative effective magnetic pressure instability
Authors: Kemel K. , Brandenburg A. , Kleeorin N. , Rogachevskii I.
Published: February 2012

As was demonstrated in earlier studies, turbulence can result in a negative contribution to the effective mean magnetic pressure, which, in turn, can cause a large‐scale instability. In this study, hydromagnetic mean‐field modelling is performed for an isothermally stratified layer in the presence of a horizontal magnetic field. The negative effective magnetic pressure instability (NEMPI) is comprehensively investigated. It is shown that, if the effect of turbulence on the mean magnetic tension force vanishes, which is consistent with results from direct numerical simulations of forced turbulence, the fastest growing eigenmodes of NEMPI are two‐dimensional. The growth rate is found to depend on a parameter β* characterizing the turbulent contribution of the effective mean magnetic pressure for moderately strong mean magnetic fields. A fit formula is proposed that gives the growth rate as a function of turbulent kinematic viscosity, turbulent magnetic diffusivity, the density scale height, and the parameter β*. The strength of the imposed magnetic field does not explicitly enter provided the location of the vertical boundaries are chosen such that the maximum of the eigenmode of NEMPI fits into the domain. The formation of sunspots and solar active regions is discussed as possible applications of NEMPI (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Hα observations of the California Nebula (NGC 1499) with DEFPOS
Authors: Şahan M. , Aksaker N. , Yeǧingil İ.
Published: February 2012

A dual étalon Fabry‐Pérot spectrometer called DEFPOS has been used for observing physical properties of HII regions and planetary nebulae since May 2007 (Aksaker et al. 2009, 2011; Şahan et al. 2009; Şahan 2011). In this study, the Hα measurements of the HII region NGC 1499 (California Nebula) have been investigated with a 4′ circular field of view over a 200 km s–1 (4.4 Å) spectral window. These measurements provide information about the densities, line widths, and radial velocities of the surrounding NGC 1499 nebula. The intensities, the radial velocities and the line widths of the Hα emission line vary from 397.75 R to 1044.14 R, –4.88 km s–1 to –1.02 km s–1, and 36.72 km s–1 to 42.81 km s–1, respectively (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spot activity on HD 89546 (FG UMa) from long‐term photometry
Authors: Özdarcan O. , Evren S. , Henry G.W.
Published: February 2012

We present the analysis of 20 years of time‐series BV photometry of the SB1 RS CVn binary HD 89546. The system's yearly mean V brightness, the B – V color index, the photometric period, and the light curve amplitude all show clear cyclic variability with an ≈9‐year time scale. We also find some evidence for brightness variability on a time scale longer than the 20‐year time span of our observations, perhaps indicating a longer cycle analogous to the solar Gleissberg cycle. We estimate the unspotted V magnitude of HD 89546 to be 7.m154, which is ≈0.m2 brighter than the observed maximum brightness. Spot modelling of the system shows that spot temperature variations affect the observed B – V color as well as the V brightness. Two active longitudes are observed, centered around 180° and 360° longitude on the G9 III primary, each covering a longitude range of 120°. Furthermore, two inactive longitude zones are seen spanning only 60° between the two active longitudes. The longitudinal distribution of the spots exhibits no strong cyclic variability but does show rapid jumps of 120° that look like the flip‐flop phenomenon. We estimate the differential rotation coefficient of the star as k = 0.086 by considering the range of observed photometric period variations and assumed latitudinal spot variations over 45° (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Human teratogens update 2011: Can we ensure safety during pregnancy?
Authors: Rasmussen Sonja A.
Published: February 2012

Anniversaries of the identification of three human teratogens (i.e., rubella virus in 1941, thalidomide in 1961, and diethylstilbestrol in 1971) occurred in 2011. These experiences highlight the critical role that scientists with an interest in teratology play in the identification of teratogenic exposures as the basis for developing strategies for prevention of those exposures and the adverse outcomes associated with them. However, an equally important responsibility for teratologists is to evaluate whether medications and vaccines are safe for use during pregnancy so informed decisions about disease treatment and prevention during pregnancy can be made. Several recent studies have examined the safety of medications during pregnancy, including antiviral medications used to treat herpes simplex and zoster, proton pump inhibitors used to treat gastroesophageal reflux, and newer‐generation antiepileptic medications used to treat seizures and other conditions. Despite the large numbers of pregnant women included in these studies and the relatively reassuring results, the question of whether these medications are teratogens remains. In addition, certain vaccines are recommended during pregnancy to prevent infections in mothers and infants, but clinical trials to test these vaccines typically exclude pregnant women; thus, evaluation of their safety depends on observational studies. For pregnant women to receive optimal care, we need to define the data needed to determine whether a medication or vaccine is “safe” for use during pregnancy. In the absence of adequate, well‐controlled data, it will often be necessary to weigh the benefits of medications or vaccines with potential risks to the embryo or fetus. Birth Defects Research (Part A), 2012. © Published 2012 Wiley Periodicals, Inc.
Exposure system to study hypotheses of ELF and RF electromagnetic field interactions of mobile phones with the central nervous system
Authors: Murbach Manuel , Christopoulou Maria , Crespo‐Valero Pedro , Achermann Peter , Kuster Niels
Published: February 2012

A novel exposure system for double‐blind human electromagnetic provocation studies has been developed that satisfies the precision, control of fields and potential artifacts, and provides the flexibility to investigate the response of hypotheses‐driven electromagnetic field exposure schemes on brain function, ranging from extremely low frequency (ELF) to radio frequency (RF) fields. The system can provide the same exposure of the lateral cerebral cortex at two different RF frequencies (900 and 2140 MHz) but with different exposure levels at subcortical structures, and also allows uniform ELF magnetic field exposure of the brain. The RF modulation and ELF signal are obtained by a freely programmable arbitrary signal generator allowing a wide range of worst‐case exposure scenarios to be simulated, including those caused by wireless devices. The maximum achievable RF exposure is larger than 60 W/kg peak spatial specific absorption rate averaged over 10 g of tissue. The maximum ELF magnetic field exposure of the brain is 800 A/m at 50 Hz with a deviation from uniformity of 8% (SD). Bioelectromagnetics 33:527–533, 2012. © 2012 Wiley Periodicals, Inc.
Improved phosphate removal by selective sludge discharge in aerobic granular sludge reactors
Authors: Bassin J.P. , Winkler M.‐K.H. , Kleerebezem R. , Dezotti M. , van Loosdrecht M.C.M.
Published: February 2012

Two lab‐scale aerobic granular sludge sequencing batch reactors were operated at 20 and 30°C and compared for phosphorus (P) removal efficiency and microbial community composition. P‐removal efficiency was higher at 20°C (>90%) than at 30°C (60%) when the sludge retention time (SRT) was controlled at 30 days by removing excess sludge equally throughout the sludge bed. Samples analyzed by fluorescent in situ hybridization (FISH) indicated a segregation of biomass over the sludge bed: in the upper part, Candidatus Competibacter phosphatis (glycogen‐accumulating organisms—GAOs) were dominant while in the bottom, Candidatus Accumulibacter phosphatis (polyphosphate‐accumulating organisms—PAOs) dominated. In order to favour PAOs over GAOs and hence improve P‐removal at 30°C, the SRT was controlled by discharging biomass mainly from the top of the sludge bed (80% of the excess sludge), while bottom granules were removed in minor proportions (20% of the excess sludge). With the selective sludge removal proposed, 100% P‐removal efficiency was obtained in the reactor operated at 30°C. In the meantime, the biomass in the 30°C reactor changed in color from brownish‐black to white. Big white granules appeared in this system and were completely dominated by PAOs (more than 90% of the microbial population), showing relatively high ash content compared to other granules. In the reactor operated at 20°C, P‐removal efficiency remained stable above 90% regardless of the sludge removal procedure for SRT control. The results obtained in this study stress the importance of sludge discharge mainly from the top as well as in minor proportions from the bottom of the sludge bed to control the SRT in order to prevent significant growth of GAOs and remove enough accumulated P from the system, particularly at high temperatures (e.g., 30°C). Biotechnol. Bioeng. 2012; 109:1919–1928. © 2012 Wiley Periodicals, Inc.
Effects of tirapazamine on experimental colorectal liver metastases after radiofrequency ablation1
Authors: Govaert K M , Nijkamp M W , Emmink B L , Steller E J A , Minchinton A I , Kranenburg O , Borel Rinkes I H M
Published: February 2012

Background

Radiofrequency ablation (RFA) is a common procedure for the management of colorectal liver metastases. RFA-generated lesions are surrounded by a rim of hypoxia that is associated with aggressive outgrowth of intrahepatic micrometastases. Hypoxia-activated prodrugs such as tirapazamine are designed selectively to induce apoptosis in tumour cells under hypoxic conditions. Therefore, it was hypothesized that tirapazamine may have therapeutic value in limiting hypoxia-associated tumour outgrowth following RFA.

Methods

Murine C26 and MC38 colorectal cancer cells were grown under hypoxia and normal oxygenation in vitro, and treated with different concentrations of tirapazamine. Apoptosis and cell cycle distribution were assessed by western blot and fluorescence-activated cell sorting analysis. Proliferative capacity was tested by means of colony-formation assays. Mice harbouring microscopic colorectal liver metastases were treated with RFA, followed by a single injection of tirapazamine (60 mg/kg) or saline. Tumour load was assessed morphometrically 7 days later.

Results

Tirapazamine induced apoptosis of colorectal tumour cells under hypoxia in vitro. Under normal oxygenation, tirapazamine caused a G2 cell cycle arrest from which cells recovered partly. This reduced, but did not abolish, colony-forming capacity. A single dose of tirapazamine largely prevented accelerated outgrowth of hypoxic micrometastases following RFA. Tirapazamine administration was associated with minimal toxicity.

Conclusion

Tirapazamine induced apoptosis in colorectal cancer cells in a hypoxia-dependent manner and potently suppressed hypoxia-associated outgrowth of liver metastases with limited toxicity. This warrants further study to assess the potential value of tirapazamine, or other hypoxia-activated prodrugs, as adjuvant therapeutics following RFA treatment of colorectal liver metastases.
Analytical solutions of N‐person games
Authors: Szilagyi Miklos N.
Published: February 2012

The possibility of analytical solutions of N‐person games is presented. A simple formula provides valuable information about the outcomes of such games with linear payoff functions and Pavlovian agents. Experiments performed with our simulation tool for the multiagent stag hunt dilemma game are presented. For the case of Pavlovian agents the game has nontrivial but remarkably regular solutions. If both payoff functions are linear and the real solutions of Eq. (2) are both positive, then the analytical solutions are remarkably accurate. © 2012 Wiley Periodicals, Inc. Complexity, 2012
Characterization of large‐sized Nd:YAG single crystals grown by horizontal directional solidification
Authors: Han Jiecai , Guo Huaixin , Zhang Mingfu , Song Ningning , Xu Chenghai
Published: February 2012

Nd3+‐doped Y3Al5O12 single crystals have been grown by the horizontal directional solidification (HDS) method in different thermal zone. The Grashof (Gr), Prandtl (Pr), Marangoni (Ma) and Rayleigh (Ra) numbers of melt in HDS system have been discussed for our experimental system to understand the mechanism of melt flow patterns and concentration gradient of dopant. The concentration gradient of Nd3+ ions was explained with melt flow processes during crystal growth in different thermal zone, and results indicated that high growth temperature will be helpful for uniformity of dopant in HDS‐grown single crystal. The main microscopic growth defects such as bubbles and irregular inclusions in HDS‐grown Nd:YAG crystals were observed, and the causes were discussed as well. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of amorphous, I and II forms of clopidogrel hydrogen sulfate
Authors: Lu Jie , Wang Jing , Rohani S.
Published: February 2012

In this work the amorphous, I and II forms of clopidogrel hydrogen sulfate (CHS) were prepared and characterized by use of powder X‐ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The labile precipitate and oiling out during reactive crystallization were also firstly reported. Based on the solubility and thermochemical data, the amorphous form and I form is found to be monotropically related, while the I form and II form are enantiotropically related. In addition, both transformations from anhydrous form to I form and from I form to II form are greatly temperature‐dependent, which gives us a window to prepare each pure form. These results will contribute a better understanding about the polymorphic nature and crystallization mechanism of clopidogrel hydrogen sulfate. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Picky eating in adults: Results of a web‐based survey.
Authors: Wildes Jennifer E. , Zucker Nancy L. , Marcus Marsha D.
Published: February 2012

Objective:

To gather information about picky eating and its correlates in adults and to determine whether picky eating is distinct from other eating disorder symptoms.

Method:

Nearly 6,895 adults completed a web‐based survey of picky eating behaviors, eating disorder symptoms, and putative associated features. Latent class analysis was used to identify groups based on picky eating and eating disorder symptoms, and groups were compared on salient demographic and clinical characteristics.

Results:

The latent class analysis identified four distinct groups that differed in severity of clinical correlates and levels of impairment. Morbidity was highest in the comorbid picky eating/eating disorder group, followed by the eating disorder, picky eating, and low pathology groups, respectively.

Discussion:

Future research is needed to document the continuity of picky eating from childhood, establish the epidemiology of picky eating in adults, clarify thresholds of clinical significance, and elucidate clinical features that will inform nosology. © 2012 by Wiley Periodicals, Inc. (Int J Eat Disord 2012)
Sleep problems are associated with binge eating in women
Authors: Trace Sara E. , Thornton Laura M. , Runfola Cristin D. , Lichtenstein Paul , Pedersen Nancy L. , Bulik Cynthia M.
Published: February 2012

Objective:

We examined the association among current self‐reported sleep problems, lifetime binge eating (BE), and current obesity in women from the Swedish Twin study of Adults: Genes and Environment.

Method:

Logistic regression analyses were used to evaluate these associations in 3,790 women aged 20–47 years.

Results:

BE was reported by 244 (6.4%) women and was positively associated with not getting enough sleep (p < .015), sleeping poorly (p < .001), problems falling asleep (p < .001), feeling sleepy during work or free time (p < .001), and disturbed sleep (p < .001). These same sleep variables, as well as napping and being a night person, were also significantly associated with obesity. The associations between BE and sleep remained after accounting for obesity.

Discussion:

This investigation offers empirical support for an independent association between sleep problems and BE, which is likely due to complex psychological, biological, neuroendocrine, and metabolic factors. © 2012 by Wiley Periodicals, Inc.
The use of multiple methods of compensatory behaviors as an indicator of eating disorder severity in treatment‐seeking youth
Authors: Colleen Stiles‐Shields E. , Labuschagne Zandrè , Goldschmidt Andrea B. , Doyle Angela Celio , Grange Daniel Le
Published: February 2012

Objective:

This study investigated the use and frequency of multiple methods of compensatory behaviors and how they relate to eating‐related and general psychopathology for youth with eating disorders (ED).

Method:

Participants were 398 referrals to a pediatric ED treatment program (91.2% female; M age = 14.9 ± 2.2). ANOVA and chi‐square tests compared participants reporting multiple methods of compensatory behaviors, single method of compensatory behaviors, and no compensatory behaviors on measures of ED and general psychopathology. Partial correlations examined associations between compensatory behavior, frequency and severity of ED and general psychopathology.

Results:

Participants reporting multiple methods of compensatory behaviors had significantly greater ED and general psychopathology than the other groups (ps < .001). Frequency of compensatory behaviors was associated with ED psychopathology (partial r = .14; p = .007) but not with general psychopathology.

Discussion:

Engaging in multiple methods of compensatory behaviors is related to greater ED and general psychopathology, whereas frequency is only related to greater ED symptom severity. © 2012 by Wiley Periodicals, Inc.
Neuropsychological weaknesses in anorexia nervosa: Set‐shifting, central coherence, and decision making in currently ill and recovered women
Authors: Danner Unna N. , Sanders Nicole , Smeets Paul A.M. , van Meer Floor , Adan Roger A.H. , Hoek Hans W. , van Elburg Annemarie A.
Published: February 2012

Objective:

The purpose of this study is to examine set‐shifting, central coherence, and decision making in women currently ill with anorexia nervosa (AN), women recovered from AN, and healthy control women. We aim to test whether these neuropsychological weaknesses persist after recovery, and explore relations between the impairments

Results:

Compared to control women, ill and recovered women showed poor set‐shifting and decision making. There were strong correlations between set‐shifting and central coherence in the ill and recovered women. Decision making did not correlate with the other measures.

Discussion:

The present findings suggest that impaired set‐shifting and decision making are stable traits in women with AN. Because individual differences within these groups were large, a rigid thinking style is only present in a (sub)population of ill and recovered women. Decision‐making performance is not related to a rigid thinking style, but further research in this area is warranted. © 2012 by Wiley Periodicals, Inc.
Autoimmunity against M2 muscarinic acetylcholine receptor induces myocarditis and leads to a dilated cardiomyopathy‐like phenotype
Authors: Yoshizawa Akihiro , Nagai Shigenori , Baba Yukiko , Yamada Taketo , Matsui Minoru , Tanaka Hikaru , Miyoshi Shun‐ichiro , Amagai Masayuki , Yoshikawa Tsutomu , Fukuda Keiichi , Ogawa Satoshi , Koyasu Shigeo
Published: February 2012

Patients with dilated cardiomyopathy (DCM) often have autoantibodies against cardiac antigens including the M2 muscarinic acetylcholine receptor (M2R). To elucidate the role of autoimmunity against M2R in disease development, we induced an immune response against M2R by adoptive transfer into Rag2–/– mice of splenocytes from M2R–/– mice immunized with a recombinant M2R protein. T lymphocytes transiently infiltrated the heart in recipient mice followed by morphological changes in cardiomyocytes. These mice produced IgG antibodies against M2R, which bound to cardiomyocytes in vivo and decreased the amplitude of calcium signals in isolated rat cardiomyocytes in vitro. Recipient mice showed increased heart weights associated with increased intraventricular diameter, decreased systolic function, and increased action potential duration, which are characteristics of DCM. Our results suggest that myocarditis and DCM associated with the presence of anti‐M2R antibodies are autoimmune diseases with a risk of progressing to the terminal stage. Our mouse model will be useful in the analysis of the molecular mechanisms of disease progression and the development of new therapies for DCM.
Synthesis and Toxicity of New Ring‐Fused Imidazo[5,4‐f]benzimidazolequinones and Mechanism Using Amine N‐Oxide Cyclizations
Authors: Fagan Vincent , Bonham Sarah , McArdle Patrick , Carty Michael P. , Aldabbagh Fawaz
Published: February 2012

A new synthetic route to ring‐fused imidazo[5,4‐f]benzimidazoles is reported that can be used to access symmetrical and unsymmetrical quinone anticancer agents. Oxone in formic acid allows cyclisation of o‐tert‐aminoacetanilides to give ring‐fused benzimidazoles and imidazobenzimidazoles in superior yields. A mechanism for these oxidative cyclisations is proposed that proceeds through a hydrogen‐bonded amine N‐oxide intermediate. The amine N‐oxide is shown to act as an oxidant in the aromatisation to the imidazole ring. X‐ray crystal structures of the dimorpholine N‐oxide intermediate and bis[1,4]oxazinoimidazo[5,4‐f]benzimidazolequinone bis(trifluoroacetate) adduct are included. Two unsymmetrical quinones are shown to have greater cytotoxicity than the previously reported imidazobenzimidazolequinones.
Cyclocondensation Reactions between 2‐Acyl‐3‐indoleacetic Acid Derivatives and Phenylglycinol: Enantioselective Synthesis of 1‐Substituted Tetrahydro‐β‐carboline Alkaloids
Authors: Amat Mercedes , Subrizi Fabiana , Elias Viviane , Llor Núria , Molins Elies , Bosch Joan
Published: February 2012

Cyclocondensation reactions between a variety of 2‐acyl‐3‐indoleacetic acid derivatives and (R)‐phenylglycinol were studied. Successful results were obtained from N‐alkyl keto acid derivatives. The resulting tetracyclic lactams provide straightforward access to enantiopure 1‐substituted tetrahydro‐β‐carboline alkaloids.
Verdazyl Radicals as Substrates for Organic Synthesis: The Synthesis and Characterization of [12]‐, [13]‐, and [21]‐Paraheteraphanes
Authors: Cumaraswamy Abbarna A. , Hamer Gordon K. , Georges Michael K.
Published: February 2012

A tandem intermolecular–intramolecular 1,3‐dipolar cycloaddition sequence with the bis‐azomethine imine derived from a para‐aryl‐substituted bis‐verdazyl radical has been used to form a series of [n]‐paraheteraphanes, which form exclusively by a [1+1] double cycloaddition reaction, with no evidence for the formation of the [2+2] quadruple cycloadduct products. 1H NMR spectroscopic studies show that rotation of the phenyl ring of these compounds is affected by the size and structure of the [n]‐paraheteraphane cavity.
Highly Efficient Synthesis of Ureas and Carbamates from Amides by Iodosylbenzene‐Induced Hofmann Rearrangement
Authors: Liu Peng , Wang Zhiming , Hu Xianming
Published: February 2012

A simple and efficient method for the synthesis of 1,3‐disubstituted ureas and carbamates from amides by using iodosylbenzene as the oxidant is described. Symmetric and asymmetric ureas and carbamates can be prepared by this procedure in up to 98 % yield. Ureidopeptides can also be prepared in good yield by this method.
The Information Content of Model‐Free Implied Volatility
Authors: Cheng Xin , Fung Joseph K.W.
Published: February 2012

This study examines the information content of model‐free implied volatility (MFIV) estimates with respect to the options and futures markets in Hong Kong. In this study, the volatility forecasting performance of MFIV is compared, using different prediction horizons, to IV estimates based on Black's futures option pricing model (BIV) and time‐series forecasts based on historical volatility (TS‐HV). The results show that the BIV prediction is unbiased for different horizon forecasts. MFIV outperforms TS‐HV forecasts and, most importantly, BIV subsumes the information content of both MFIV and TS‐HV forecasts. The results are largely maintained for next‐day forecasts but the forecasting quality of the two IV measures declines as expiration day approaches. The information contents of MFIV and TS‐HV forecasts are complementary. © 2012 Wiley Periodicals, Inc. Jrl Fut Mark 32:792‐806, 2012
Equipment for advance probing and for advance treatment of the ground from the TBM / Einrichtungen zur Vorauserkundung und vorauseilenden Gebirgsbehandlung auf einer TBM
Authors: Heim André
Published: February 2012

In the planning phase of a tunnel project, site investigations are carried out, geotechnical data is collected and analyses produced. A favourable and practical tunnel alignment is determined and the geological units to be bored through are described, classified and the risks for tunnelling are estimated. Nonetheless, the ground passed through will always have surprises in store, in mechanised as in conventional tunnelling, in hard rock and in loose ground. Rock type, hardness and strength, degree of jointing, occurrence and formation of fault zones and karst features, formation water ingress etc. can all deviate from the forecast information.

This article is concerned with the subject of mechanised tunnel driving in hard rock, in particular with the equipment for advance probing integrated into the machine and methods of advance treatment of geologically conditioned disruptions and deviations to ensure that mechanised boring can continue in safety. This includes details of the advance probing methods used from drilling, through radar technology, to seismic applications and their possible combinations. The advance treatment of the ground that follows or is directly linked to the investigation is described through concepts and practical examples (e.g. grouting, advance drilling and pipe screens).

In der Planfeststellungsphase eines Tunnelbauprojekts werden Vorerkundungen durchgeführt, geotechnische Daten gesammelt und Analysen erstellt. Eine günstige und durchführbare Tunneltrasse wird festgelegt und die zu durchörternden geologischen Einheiten beschrieben, klassifiziert und auf tunnelvortriebsrelevante Risiken eingeschätzt. Dennoch hält der Baugrund für den maschinellen wie auch den konventionellen Tunnelbau sowohl im Hart‐ als auch im Lockergestein immer wieder Überraschungen bereit. Gesteinstyp, ‐härte und ‐festigkeit, Klüftungsgrad, Auftreten und Ausbildung von Störzonen und Karstvorkommen, Bergwasserzutritt u. ä. können von den prognostizierten Werten und Erkenntnissen abweichen.

Der Beitrag befasst sich mit der Thematik des maschinellen Tunnelvortriebs im Hartgestein, insbesondere mit den maschinenintegrierten Einrichtungen zur Vorauserkundung sowie mit den Möglichkeiten, das Gebirge im geologisch bedingten Stör‐ oder Abweichungsfall soweit vorauszubehandeln, damit der maschinelle Vortrieb gesichert fortgeführt werden kann. Dabei werden die genutzten Vorauserkundungsmethoden von konventionell bohrend über Radartechnologie bis hin zu seismischen Anwendungen und möglichen Kombinationen der Methoden erörtert. Die an die Vorauserkundung anschließende oder auch mit ihr direkt verknüpfte Vorausbehandlung des Gebirges wird anhand von Konzepten und Praxisbeispielen (z.B. Injektionen, Vorausbohrungen und Rohrschirme) dargestellt.