bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-focus image fusion for enhancing fiber microscopic images
Authors: Wang RongWu , Xu Bugao , Zeng Peifeng , Zhang Xianmiao
Published: February 2012

Accurate measurement and identification of fibers using magnified digital images relies mainly on the quality of the fiber image. At a given power of magnification, a light microscope has a limited depth of field that may not cover the entire depth space of a fiber sample on the slide and thus disallows all fibers in the image from being well focused, regardless of focus positions. This paper introduces an image-fusion technique to solve mal-focused fibers in a microscopic image to ensure optimal image quality for fiber measurements. This new technique utilizes multiple images of the same view taken at consecutive depths, calculates a focus measure of every pixel in each image, and constructs a matrix to register the image layer that has the maximum focus measure for every pixel. The matrix can be further modified and then used as a map to reconstruct a new image that contains only the best-focused pixels out of the captured images. The fused image combines selected features of multi-focus images so that unfocused fibers can be realistically amended and blurring fiber edges can be sharpened. Compared to the data measured from a single-focus image, the data taken from the fused image can greatly improve the accuracy of fiber thickness measurements.
Automatic detecting anthropometric landmarks based on spin image
Authors: Li Yue , Zhong Yueqi
Published: February 2012

In this paper, we present a method to detect anthropometric landmarks on 3D human scans automatically. Our method is a template-based approach, which builds correspondences between instance models and a template model. Spin images are used to construct the similarity measure, which represents the shape features parametrically. A vertex on the instance model will be regarded as the landmark when its similarity measure against a corresponding landmark on the template model is of maximum value. Normal variation and bounding boxes are employed to speed up the comparison of spin images. The algorithm is verified on scanned human bodies with various shapes. Forty-seven landmarks are detected on the instance body. The results show that most landmarks are found accurately. Furthermore, we demonstrate the implementation of using our detected landmarks in automatic body measurement.
Bio-electrospinning of poly(l-lactic acid) hollow fibrous membrane
Authors: Shih Yung-Hsun , Yang Jen-Chang , Li Su-Han , Yang Wei-Chung Vivian , Chen Chien-Chung
Published: February 2012

We present a bio-electrospinning technique for preparing cell-containing, oriented tubular scaffold intended for use as a nerve guide conduit (NGC). With a coaxial spinneret, solutions of PC-12 cells and poly(l-lactic acid) (PLLA) were delivered to the core and shell parts of the spinneret, respectively. When electrostatic field was applied, core/shell fiber was electrospun and collected. The electrospun fibers’ morphology was characterized via scanning electron microscopy (SEM) and optical microscopy. Two structural characteristics were found: (1) the larger, hollow fibers had diameters in tens of micrometers and wall thicknesses around few micrometers, and (2) improved orientation in a preferred direction with the aid of a rotating collection device. Finally, fluorescent PC12 cells were found not only to exist and survive inside these hollow fibers, but also, upon addition of nerve growth factor, to undergo differentiation with neurite extended along the hollow fibers in the desired direction. All of these results demonstrate its potential application for NGC.
Prediction of bending rigidity for laminated fabric with adhesive interlining by a laminate model considering tensile and in-plane compressive moduli
Authors: Kim KyoungOk , Inui Shigeru , Takatera Masayuki
Published: February 2012

The purpose of this study is to predict bending rigidity of laminated fabric with adhesive interlining considered tensile and in-plane compressive moduli. The predicting method considering those moduli was proposed by theoretical derivation based on laminate model. Tensile and in-plane compressive moduli of neutral surface for face fabric and adhesive interlining respectively before laminating and modulus for bending rigidity were considered independently. The calculating equation for in-plane compressive modulus was proposed from the relationship between bending rigidities and tensile properties. The proposed predicting method was verified experimentally. Bending rigidities, tensile properties and thicknesses of adhesive interlinings, face fabrics and laminated fabrics with adhesive interlinings were measured by KES-FB system. The in-plane compressive moduli of adhesive interlinings were calculated by the proposed equation with the results of tensile properties for face fabrics. With the results of tensile and in-plane compressive moduli, the bending rigidities of laminated fabric with adhesive interlinings were calculated. The predicted bending rigidities considered with measured tensile properties and calculated in-plane compressive moduli were precisely closer to experimental results than the ones of the laminated model from our previous study. Therefore, this model gives a new way to predict bending rigidity of laminated fabric with adhesive interlining.
The Contest of Rival Capitalisms
Authors: Thornton William H. , Thornton Songok Han
Published: February 2012

A new authoritarian order is taking shape, this time within rather than against the capitalist world order. Globalization, in short, is shedding its liberal cloak. Post–Cold War triumphalism was premature in the funeral it staged for the Second World, defined in terms of its autocracy rather than communism. The capitalist character of the new Second World lulls Western globalists into moral as well as geopolitical (hence moral realist) indifference. For many in high places, it is still inconceivable that global capitalism could be a house divided. “Globalization” turns out to be anything but the steadfast ally of democratization it purports to be. It is in fact the greatest gift to a new breed of authoritarian capitalists. The case of China alone is enough to dispel the notion that capitalism and democracy are two sides of the same globalist coin. But Sino-globalization is only unique in that it makes no pretense about its authoritarian ends and means. To revitalize democratization as a global force, a radically different mode of globalization will have to be fostered. We call this the Global Third Way, but what it amounts to is People Power without borders.
Lamotrigine augmentation of serotonin reuptake inhibitors in treatment-resistant obsessive–compulsive disorder: a double-blind, placebo-controlled study
Authors: Bruno Antonio , Micò Umberto , Pandolfo Gianluca , Mallamace Domenico , Abenavoli Elisabetta , Di Nardo Floriana , D’Arrigo Concetta , Spina Edoardo , Zoccali Rocco A , Muscatello Maria Rosaria A
Published: February 2012

The present 16-week double-blind, randomized, placebo-controlled trial had the aim to explore the efficacy of lamotrigine add-on pharmacotherapy on clinical symptomatology and cognitive functioning in a sample of patients with treatment-resistant obsessive–compulsive disorder (OCD) receiving serotonin reuptake inhibitors (SRIs). After clinical and neurocognitive assessments, patients were randomly allocated to receive, in a double-blind design, 100 mg/day of lamotrigine or a placebo. A final sample of 33 patients completed the study. The results obtained indicate that lamotrigine added to stable SRI treatment substantially improved obsessive–compulsive (Yale–Brown Obsessive Compulsive Scale: obsessions, p < 0.0001; compulsions, p < 0.0001; total score, p < 0.0001), and affective symptoms (Hamilton Rating Scale for Depression p < 0.0001). Regarding cognitive functions, improvement was observed only in Semantic Fluency ( p = 0.004). The findings provide evidence that lamotrigine augmentation of SRI treatment is well tolerated and may be proposed as an effective therapeutic strategy to improve outcome in treatment-resistant OCD.
Possible interactions between recirculated landfill leachate and the stabilized organic fraction of municipal solid waste
Authors: Calabrò Paolo S , Mancini Giuseppe
Published: February 2012

The stabilized organic fraction of municipal solid waste (SOFMSW) is a product of the mechanical/biological treatment (MBT) of mixed municipal solid waste (MMSW). SOFMSW is considered a ‘grey’ compost and the presence of pollutants (particularly heavy metals) and residual glass and plastic normally prevents agricultural use, making landfills the typical final destination for SOFMSW. Recirculation of leachate in landfills can be a cost-effective management option, but the long-term sustainability of such a practice must be verified. Column tests were carried out to examine the effect of SOFMSW on leachate recirculation. The results indicate that organic matter may be biologically degraded and metals (copper and zinc) are effectively entrapped through a combination of physical (adsorption), biological (bacterial sulfate reduction), and chemical (precipitation of metal sulfides) processes, while other chemicals (i.e. ammonia nitrogen and chloride) are essentially unaffected by filtration through SOFMSW.
Computational analysis of blood clot dissolution using a vibrating catheter tip
Authors: Lee Jeong Hyun , Oh Jin Sun , Yoon Bye Ri , Choi Seung Hong , Rhee Kyehan , Jho Jae Young , Han Moon Hee
Published: February 2012

We developed a novel concept of endovascular thrombolysis that employs a vibrating electroactive polymer actuator. In order to predict the efficacy of thrombolysis using the developed vibrating actuator, enzyme (plasminogen activator) perfusion into a clot was analyzed by solving flow fields and species transport equations considering the fluid structure interaction. In vitro thrombolysis experiments were also performed. Computational results showed that plasminogen activator perfusion into a clot was enhanced by actuator vibration at frequencies of 1 and 5 Hz. Plasminogen activator perfusion was affected by the actuator oscillation frequencies and amplitudes that were determined by electromechanical characteristics of a polymer actuator. Computed plasminogen activator perfused volumes were compared with experimentally measured dissolved clot volumes. The computed plasminogen activator perfusion volumes with threshold concentrations of 16% of the initial plasminogen activator concentration agreed well with the in vitro experimental data. This study showed the effectiveness of actuator oscillation on thrombolysis and the validity of the computational plasminogen activator perfusion model for predicting thrombolysis in complex flow fields induced by an oscillating actuator.
Experimental investigation of a thermo-acoustic prime mover with helium–argon mixtures as working gases
Authors: Liu Y W , He Y L
Published: February 2012

In order to further investigate the effect of the working gas (especially, the helium–argon mixture) on the actual operating characteristics (including static and dynamic characteristics) of a thermo-acoustic engine, an experimental standing-wave thermo-acoustic engine was built up in this study. The thermo-acoustic system was introduced in detail, and experimental results on the thermodynamic characteristics of the system with helium–argon mixtures, especially the dynamic and oscillating characteristics, were also presented. At different molar fractions in the helium–argon mixture, under different charging pressures, the pressure ratio and the pressure amplitude of the thermo-acoustic system gradually increase with heating temperature. Under given conditions of the charging pressure and heating temperature, there exists an optimal molar fraction in the helium–argon mixture. It is obvious that using a certain proportion of helium–argon mixture as the working gas, the on-set temperature of the thermo-acoustic system can be effectively reduced and this is helpful in using low-quality energy and enhancing the thermodynamic efficiency of the whole system. Using helium–argon mixtures can widen the application range of the thermo-acoustic system and obtain any frequency between the resonance frequencies of two pure substances. However, the unexpected large fluctuation of the resonance frequency will make the engineering application of the system difficult. These results will provide a reliable experimental basis for further improving the thermodynamic performance of the thermo-acoustic system and broaden the application range.
Evaluating the Impact of Microfinance on Savings and Income in Sri Lanka:Quasi-experimental Approach Using Propensity Score Matching
Authors: Silva Indunil De
Published: February 2012

The study applied recent advances in propensity score matching methods to assess the impact of microfinance on household income and savings. Results suggest that overall programme participants’ benefit incidence is indeed pro-poor. With respect to both household per capita income and savings, programme participation definitely has a positive impact for all low-income households. Consequently, this article’s findings have several important policy implications. The large positive impact of participating in microfinance programmes on household income and savings suggest that microfinance programmes may improve household status in terms of wealth. The regressive effect on household per capita income suggests that poorer households do not feel as much the effects of the intervention compared to richer households. The policy implication of this regressive effect might be that for the poorest programme participants, the availability of programme loans and savings schemes may be not sufficient to become highly productive in income-generating activities. The finding of participation in microfinance programmes not being highly effective in terms of savings for richer households highlights the importance of a robust and accurate targeting mechanism for the microfinance programme in Sri Lanka. Against the backdrop of these findings, policy planners and microfinance practitioners could re-examine the targeting approach of microfinance in Sri Lanka. Finally, the principal message that emerges from the study is: there are quantitatively non-negligible, average gains from microfinance on household savings and income, especially for the poor.

JEL Classification: O16, C14, C21, G21
Collective identity, rationality and collective political action
Authors: Opp Karl-Dieter
Published: February 2012

This paper explores the effects of collective identity on protest behavior by applying an extended version of the theory of collective action. Hypotheses are derived about the following questions that are rarely addressed in the literature: Are there situations in which collective identity diminishes protest? The standard assumption is that collective identity increases protest behavior. Does collective identity have indirect effects – via the determinants of protest – on protest behavior? Are there feedback effects of protest participation on collective identity? The hypotheses that address these questions are tested with a three-wave panel study. Three findings are of particular interest: (1) the overall direct additive effects of identity on protest behavior are statistically not significant. (2) Evidence is provided that in solidary groups identity does not raise but reduce protest. (3) The major effects of identity are indirect: identity influences the determinants of protest.
Feasibility study on a hybrid mount system with air springs and piezo-stack actuators for microvibration control
Authors: Jang Dong-Doo , Jung Hyung-Jo , Shin Yun-Ho , Moon Seok-Jun , Moon Yeong-Jong , Oh Jungkeun
Published: February 2012

This article proposes a new hybrid mount system with air springs and piezo-stack actuators that can deliver excellent performance in the microvibration control of high-tech facilities. Air springs are one of the most popular products for vibration isolation and deliver good performance in general. Piezo-stack actuators are capable of controlling micro- and nanolevel displacement with a fast response. In order to fully utilize the isolation and leveling performances of an air spring as a passive part, it is serially connected with a piezo-stack actuator serving as an active part. As a control logic for the hybrid mount, the filtered-X least-mean-square algorithm is applied. A hybrid mount system with four hybrid mounts is configured in order to confirm the performance of the hybrid mount and its performance is verified through a series of experimental tests.
Large deflection effects in flexible energy harvesters
Authors: Elvin Niell G , Elvin Alex A
Published: February 2012

The effect of large deflection on the mechanical and electrical behaviors of flexible piezoelectric energy harvesters has not been well studied. A generalized nonlinear coupled finite element circuit simulation approach is presented in this article to study the performance of energy harvesters subjected to large deflections. The method presented is validated experimentally using three test examples consisting of (a) a static case, (b) a free vibration case, and (c) a forced vibration case. Under static conditions (when the transverse tip deflection exceeds a quarter of the cantilever length), large deflections cause geometric stiffening of the structure that reduces the tip deflection of the generator when compared to linear (i.e. small-deflection) behavior. For a cantilever generator under dynamic conditions, geometric stiffening, inertial softening, and nonlinear damping effects become significant. Large deflections both shift the resonant frequency and increase damping and can thus cause a significant reduction in output voltage when compared with small-deflection linear theory. In the finite element generator model studied in this article, these nonlinear dynamic effects become significant when the transverse tip deflection exceeds 35% of the beam length.
Vocational Identity Achievement as a Mediator of Presence of Calling and Life Satisfaction
Authors: Hirschi Andreas , Herrmann Anne
Published: February 2012

The present study explores what mechanism might be responsible for the reported link between presence of a calling in one’s career and life satisfaction. It is proposed that vocational identity achievement acts as one important mediator of this relation and that the effects can be observed even when controlling for core self-evaluations (CSEs). The study used a short-term longitudinal design based on a sample of 269 German college students from different majors. The results confirmed the mediation model, with calling predicting vocational identity achievement 6 months later and identity serving as a stronger predictor of life satisfaction, all controlling for CSEs. However, contrary to previous research, presence of calling was not directly related to life satisfaction and even showed a negative relation when vocational identity achievement was controlled. The results are interpreted to suggest a multifaceted relation between calling and life satisfaction.
Measuring Meaningful Work
Authors: Steger Michael F. , Dik Bryan J. , Duffy Ryan D.
Published: February 2012

Many people desire work that is meaningful. However, research in this area has attracted diverse ideas about meaningful work (MW), accompanied by an equally disparate collection of ways of assessing MW. To further advance study in this area, the authors propose a multidimensional model of work as a subjectively meaningful experience consisting of experiencing positive meaning in work, sensing that work is a key avenue for making meaning, and perceiving one’s work to benefit some greater good. The development of a scale to measure these dimensions is described, an initial appraisal of the reliability and construct validity of the instrument’s scores is reported using a sample of university employees ( N = 370) representing diverse occupations. MW scores correlated in predicted ways with work-related and general well-being indices, and accounted for unique variance beyond common predictors of job satisfaction, days reported absent from work, and life satisfaction. The authors discuss ways in which this conceptual model provides advantages to scholars, counselors, and organizations interested in fostering MW.
Why do people do stuff? Reconceptualizing remittance behaviour in diaspora-development research and policy
Authors: Page Ben , Mercer Claire
Published: February 2012

Attempts by policy-makers to encourage diasporas to engage in development in the Global South rely on conceptions of behaviour drawn from economics that emphasize individual choice, stimuli and motivations. This article argues that diasporas are better understood as ‘communities of practice’ in which actions are conceptualized as part of a wider social system based on embodied knowledge acquired through socialization, technology and the habituation of particular lifestyles. Using social theories of practice to analyze remittances draws attention to the symptomatic silences of dominant theorizations of behaviour. Existing theorizations underpin, and thereby uncritically endorse, potentially unsustainable development policies based on remittances. The alternative approach presented here opens up new areas for policy and research based on medium to long-term changes in the socio-technical remittance regime.
Government expenditure and growth in developing countries
Authors: Dao Minh Quang
Published: February 2012

Purpose

This article investigates the impact of the growth of the share of various government expenditure programmes in the GDP on economic growth in developing countries while taking into consideration the major issue of potential simultaneity.

Findings

Based on data from the World Bank and using two samples of 28 developing economies, we find that per capita GDP growth is dependent upon the growth of per capita public health expenditure in the GDP, growth of per capita public spending on education in the GDP, population growth, growth of the share of total health expenditure in the GDP and the share of gross capital formation in the GDP.

Practical implications

Statistical results of such empirical examination will assist policy-makers in developing countries prioritize their government expenditure in order to stimulate economic growth.

Methodology/approach

Data for all variables are from the World Development Indicators (2008 and 2010). We specify and estimate a simultaneous equations model which consists of two government expenditure growth equations and a GDP growth equation. We observe that some coefficient estimates do not have the expected sign due to possible collinearity among some independent variables.
Commentary
Authors: Boyle Raymond , Kelly Lisa W.
Published: February 2012

This short commentary piece arises from completing an Arts and Humanities Research Council (AHRC)–funded research project into the relationship between representations of business on factual television in the United Kingdom and the public’s perception and understanding of entrepreneurship. What we would like to do here is reflect on some of the implications of this work with specific regard to the research agenda around the media and civic culture. We remain convinced that even in the digital age, popular television remains a central entry point into debates about the relationship between broader civic and political culture.
Recovered, Reinvented, Reimagined
Authors: Gray Herman
Published: February 2012

This article explores the role of scripted cable television in the making and remaking of place in the conjuncture of postdisaster crisis and the neoliberal transformation of urban space. I suggest that Treme contributes to the remaking of New Orleans by engaging conceptions of authenticity, dwelling on the elements of cuisine, music, and diversity that mark New Orleans as distinctive, and highlighting individual enterprise as a condition of possibility for remaking post-Katrina New Orleans. I also suggest that because it makes for compelling quality television and provides badly needed publicity and temporary economic stimulus for the local economy, Treme, the show and the HBO production, through no fault of its own, displaces critical engagement with public policy choices and state-centered redress for economic, cultural, and social injustice and inequality.
Facile control synthesis of Ag3PO4 and morphologies effects on their photocatalytic properties
Authors: Deng Jiawei , Pang Huan , Deng DeHua , Zhang Jiangshan
Published: February 2012

We reported that Ag3PO4 exhibits excellent photocatalytic properties for organic dye decomposition under visible-light irradiation. Herein, studies of photocatalytic performance have indicated that nano rhombic dodecahedrons (S1) exhibit much higher activities than micro rhombic dodecahedrons (S3) for the degradation of organic contaminants.
Towards a framework of sustainability indicators for ‘communication for development and social change’ projects
Authors: Servaes Jan , Polk Emily , Shi Song , Reilly Danielle , Yakupitijage Thanu
Published: February 2012

This article presents an overview of the emergence of sustainability themes in communication for development and argues that there is an urgent need for a framework of sustainability indicators for communication for development and social change projects around the world. It fills a crucial gap in the growing body of literature by first synthesizing the most relevant data currently produced by global and local institutions, NGOs, UN-based organizations, academics, and professionals regarding assessment indicators for development projects, and second, produces a framework of sustainability indicators that can be used by a wide variety of people in the field to assess the sustainability of existing projects and the sustainable potential of planned ones. It then tests the framework in two representative cases.
Surface modification by multilayered Zn–Co alloy coatings
Authors: Yogesha S , Udupa K R , Hegde A C
Published: February 2012

Nanostructured multilayer alloy or composition modulated multilayer alloy coatings of Zn–Co have been developed, and their corrosion behaviours were studied by potentiodynamic polarisation and electrochemical impedance spectroscopy methods. The coatings were developed galvanostatically using square, triangular and sawtooth current pulses through single bath technique. The cyclic cathode current density and the numbers of layers have been optimised for peak performance of the coatings against corrosion. Under optimal conditions, the coatings developed using square, triangular and sawtooth current pulses were found to be respectively ∼100, 80 and 90 times more corrosion resistant than monolithic alloy of same thickness. The better corrosion resistances of the composition modulated multilayer alloy coatings were attributed to the dielectric barrier at the interface, as evidenced by dielectric spectroscopy. Surface morphology, multilayer formation and surface after corrosion tests were examined by scanning electron microscopy.
Effect of depositing parameters on microstructures and properties of multi arc ion plating ZrTiN films
Authors: Yan P , Deng J X , Lian Y S , Zhao J , Chen Z , Ai X
Published: February 2012

ZrTiN hard coatings were deposited on WC/TiC/Co cemented carbide substrate by multi arc ion plating. During the depositing, the four most important parameters are target current, nitrogen flowrate, deposition temperature and negative substrate bias voltage. This paper presented a detailed analysis of the effect of these four depositing parameters on the microstructures and properties of ZrTiN thin films respectively. In addition, we also systematically investigated the microstructure, elemental composition, crystal orientation, lattice parameter, grain size, adhesive strength and microhardness of the films. X-ray diffraction analysis indicated that only the face centred cubic phase was formed in the films, but the crystal orientation varied with different deposition conditions. Microhardness and adhesive strength of the coatings were associated with elemental composition, crystal orientation and microstructures. The optimum films obtained possessed comprehensive mechanical properties with an adhesive strength of 84·1 N and a microhardness of 30·4 GPa and exhibited the strongest (111) preferred orientation.
Nb2O5 coating of glass fibres applied by chemical vapour deposition
Authors: da Silveira C B , de Oliveira A F , de Campos S D , de Campos E A , Fraporti A D
Published: February 2012

In this study, the chemical vapour deposition (CVD) technique is used to modify the surface of Li2O–ZrO2–BaO–SiO2 glass fibre with Nb2O5, using NbCl5 as the precursor. Glass fibres were coated as follows: without thermal pretreatment but followed by air exposure after the reaction with NbCl5; without thermal treatment followed by water hydrolysis, with thermal treatment at 300°C for 2 h and air exposure; and finally, with thermal treatment and hydrolysis in water. The best result was obtained with the fibre chemically modified with Nb2O5 after heat treatment followed by water hydrolysis. This procedure resulted in fibres coated with a homogeneous layer of Nb2O5 without cracks. The fibres were characterised by scanning electron microscopy and energy dispersive X-ray spectroscopy. The fibres were evaluated in the qualitative determination of a mixture of methanol, ethanol and 1-butanol by solid phase microextraction and gas chromatography, yielding better results than those of the fibre coated with Nb2O5 prepared by metallo-organic decomposition.
Microsatellites reveal a strong subdivision of genetic structure in Chinese populations of the mite Tetranychus urticae Koch (Acari: Tetranychidae)
Authors: Sun Jing-Tao , Lian Chunlan , Navajas Maria , Hong Xiao-Yue
Published: February 2012

Background

Two colour forms of the two-spotted spider mite (Tetranychus urticaeKoch) coexist in China: a red (carmine) form, which is considered to be native and a green form which is considered to be invasive. The population genetic diversity and population genetic structure of this organism were unclear in China, and there is a controversy over whether they constitute distinct species. To address these issues, we genotyped a total of 1,055 individuals from 18 red populations and 7 green populations in China using eight microsatellite loci.

Results

We identified 109 alleles. We found a highly significant genetic differentiation among the 25 populations (globalFST= 0.506, globalFST{ENA}= 0.473) and a low genetic diversity in each population. In addition, genetic diversity of the red form mites was found to be higher than the green form. Pearson correlations between statistics of variation (ARandHE) and geographic coordinates (latitude and longitude) showed that the genetic diversity of the red form was correlated with latitude. Using Bayesian clustering, we divided the Chinese mite populations into five clades which were well congruent with their geographic distributions.

Conclusions

Spider mites possess low levels of genetic diversity, limit gene flow between populations and significant and IBD (isolation by distance) effect. These factors in turn contribute to the strong subdivision of genetic structure. In addition, population genetic structure results don't support the separation of the two forms of spider mite into two species. The morphological differences between the two forms of mites may be a result of epigenetic effects.
A minimal model of peptide binding predicts ensemble properties of serum antibodies
Authors: Greiff Victor , Redestig Henning , Lück Juliane , Bruni Nicole , Valai Atijeh , Hartmann Susanne , Rausch Sebastian , Schuchhardt Johannes , Or-Guil Michal
Published: February 2012

Background

The importance of peptide microarrays as a tool for serological diagnostics has strongly increased over the last decade. However, interpretation of the binding signals is still hampered by our limited understanding of the technology. This is in particular true for arrays probed with antibody mixtures of unknown complexity, such as sera. To gain insight into how signals depend on peptide amino acid sequences, we probed random-sequence peptide microarrays with sera of healthy and infected mice. We analyzed the resulting antibody binding profiles with regression methods and formulated a minimal model to explain our findings.

Results

Multivariate regression analysis relating peptide sequence to measured signals led to the definition of amino acid-associated weights. Although these weights do not contain information on amino acid position, they predict up to 40-50% of the binding profiles' variation. Mathematical modeling shows that this position-independent ansatz is only adequate for highly diverse random antibody mixtures which are not dominated by a few antibodies. Experimental results suggest that sera from healthy individuals correspond to that case, in contrast to sera of infected ones.

Conclusions

Our results indicate that position-independent amino acid-associated weights predict linear epitope binding of antibody mixtures only if the mixture is random, highly diverse, and contains no dominant antibodies. The discovered ensemble property is an important step towards an understanding of peptide-array serum-antibody binding profiles. It has implications for both serological diagnostics and B cell epitope mapping.
Magnetic nanoparticles: preparation, physical properties, and applications in biomedicine
Authors: Akbarzadeh Abolfazl , Samiei Mohammad , Davaran Soodabeh
Published: February 2012

Finally, we have addressed some relevant findings on the importance of having well-defined synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the preparation of monodisperse samples of relatively large quantities not only with similar physical features, but also with similar crystallochemical characteristics. Then, different methodologies for the functionalization of the prepared MNPs together with the characterization techniques are explained. Theorical views on the magnetism of nanoparticles are considered.
Kinetic nanofriction: a mechanism transition from quasi-continuous to ballistic-like Brownian regime
Authors: Jafary-Zadeh Mehdi , Reddy Chilla Damodara , Sorkin Viacheslav , Zhang Yong-Wei
Published: February 2012

Surface diffusion of mobile adsorbates is not only the key to control the rate of dynamical processes on solid surfaces, e.g. epitaxial growth, but also of fundamental importance for recent technological applications, such as nanoscale electro-mechanical, tribological, and surface probing devices. Though several possible regimes of surface diffusion have been suggested, the nanoscale surface Brownian motion, especially in the technologically important low friction regimes, remains largely unexplored. Using molecular dynamics simulations, we show for the first time, that a C60 admolecule on a graphene substrate exhibits two distinct regimes of nanoscale Brownian motion: a quasi-continuous and a ballistic-like. A crossover between these two regimes is realized by changing the temperature of the system. We reveal that the underlying physical origin for this crossover is a mechanism transition of kinetic nanofriction arising from distinctive ways of interaction between the admolecule and the graphene substrate in these two regimes due to the temperature change. Our findings provide insight into surface mass transport and kinetic friction control at the nanoscale.
Common fixed points of ordered g-quasicontractions and weak contractions in ordered metric spaces
Authors: Golubović Zoran , Kadelburg Zoran , Radenović Stojan
Published: February 2012

We introduce ordered quasicontractions and g-quasicontractions in partially ordered metric spaces and prove the respective coincidence point and (common) fixed point results. An example shows that the new concepts are distinct from the existing ones. We also prove fixed point theorems for mappings satisfying so-called weak contractive conditions in the setting of partially ordered metric space. Hence, generalizations of several known results are obtained.

Mathematics Subject Classification (2010): 47H10; 47N10.
Stability of the Jensen equation in C*-algebras: a fixed point approach
Authors: Kenary Hassan Azadi , Rezaei Hamid , Talebzadeh Saedeh , Park Choonkil
Published: February 2012

Using fixed point method, we prove the Hyers-Ulam stability of homomorphisms in C*-algebras and Lie C*-algebras and also of derivations on C*-algebras and Lie C*-algebras for the Jensen equation.

2010 Mathematics Subject Classification: 39B82; 47H10; 46L05; 39B52.
A parametric method for cumulative incidence modeling with a new four-parameter log-logistic distribution
Authors: Shayan Zahra , Ayatollahi SeyyedMohammadTaghi , Zare Najaf
Published: February 2012

Background

Competing risks, which are particularly encountered in medical studies, are an important topic of concern, and appropriate analyses must be used for these data. One feature of competing risks is the cumulative incidence function, which is modeled in most studies using non- or semi-parametric methods. However, parametric models are required in some cases to ensure maximum efficiency, and to fit various shapes of hazard function.

Methods

We have used the stable distributions family of Hougaard to propose a new four-parameter distribution by extending a two-parameter log-logistic distribution, and carried out a simulation study to compare the cumulative incidence estimated with this distribution with the estimates obtained using a non-parametric method. To test our approach in a practical application, the model was applied to a set of real data on fertility history.

Conclusions

The results of simulation studies showed that the estimated cumulative incidence function was more accurate than non-parametric estimates in some settings. Analyses of real data indicated that the proposed distribution showed a much better fit to the data than the other distributions tested. Therefore, the new distribution is recommended for practical applications to parameterize the cumulative incidence function in competing risk settings.
Anxiety-depressive disorders among irritable bowel syndrome patients in Guilan, Iran
Authors: Modabbernia Mohamad-Jafar , Mansour-Ghanaei Fariborz , Imani Ali , Mirsafa-Moghaddam Seyed-Alireza , Sedigh-Rahimabadi Massih , Yousefi-Mashhour Mahmoud , Joukar Farahnaz , Atrkar-Roushan Zahra , Bidel Siamak
Published: February 2012

Background

Psychiatric disorders are common in irritable bowel syndrome (IBS) patients. The prevalence of psychiatric disorders in IBS patients varies in different cultures. We conducted this study to determine the prevalence of psychiatric disorders

Methods

In a cross-sectional study, 256 IBS patients were selected (using the criteria of Rome III) and evaluated for psychiatric disorders. In the first phase, subjects were screened using the General Health Questionnaire 28 (GHQ28). In the second phase, those who had scores ≥ 23 were assessed through semi-structured psychiatric interviews.

Results

Thirty out of 256 subjects had no significant psychiatric symptoms after performing GHQ28. In further psychiatric evaluation of the remaining subjects (226) who suffered from some degree of a psychiatric problem, 36 were diagnosed without Anxiety/Depressive disorder. Thus 66 subjects (25.8%) were known as a group without any significant psychiatric problem. A total of 190 subjects (74.2%) with anxiety-depressive problems were diagnosed; 89 were suffering from pure anxiety disorders, 41 were suffering from depressive disorders and 60 had co-morbid anxiety-depressive disorders. When comparing anxiety-depressive patients (n = 190) with normal subjects (n = 66), gender (P = 0.016), occupation (P = 0.002) and intensity of IBS (P < 0.001) showed statistically significant differences.

Conclusion

The high prevalence of anxiety-depressive disorders in this study indicates the necessity of psychiatric assessment, early diagnosis and treatment of the patients with IBS. It may improve management of the patients suffering from IBS.
Single-station SVD-based polarization filtering of ground roll: Perfection and investigation of limitations and pitfalls
Authors: Tiapkina Olena , Landrø Martin , Tyapkin Yuriy , Link Brian
Published: February 2012

The advent of single receiver point, multi-component geophones has necessitated that ground roll be removed in the processing flow rather than through acquisition design. A wide class of processing methods for ground-roll elimination is polarization filtering. A number of these methods use singular value decomposition (SVD) or some related transformations. We focus on a single-station SVD-based polarization filter that we consider to be one of the best in the industry. The method is comprised of two stages: (1) ground-roll detection and (2) ground-roll estimation and filtering. To detect the ground roll, a special attribute dependent on the singular values of a three-column matrix formed by a sliding time window is used. The ground roll is approximated and subtracted using the first two eigenimages of this matrix. To limit the possible damage to the signal, the filter operates within the record intervals where the ground roll is detected and within the ground-roll frequency bandwidth only. We improve the ground-roll detector to make it theoretically insensitive to ambient noise and more sensitive to the presence of ground roll. The advantage of the new detector is demonstrated on synthetic and field data sets. We estimate theoretically and with synthetic data the attenuation of the underlying reflections that can be caused by the polarization filter. We show that the underlying signal always loses almost all the energy on the vertical component and on the horizontal component in the ground-roll propagation plane and within the ground-roll frequency bandwidth. The only signal component, if it exists, that can retain a significant part of its energy is the horizontal component orthogonal to the above plane. When 2D 3C field operations are conducted, the signal particle motion can deviate from the ground-roll propagation plane and can therefore retain some of its energy due to a set of offline reflections. In the case of 3D 3C seismic surveys, the reflected signal always deviates from the ground-roll propagation plane on the receiver lines that do not contain the source. This is confirmed with a 2.5D 3C synthetic data set. We discuss when the ability of the filter to effectively subtract the ground roll may, or may not, allow us to ignore the inevitable harm that is done to the underlying reflected waves.
Rock-physics models for bitumen-saturated sands: Fractional gradient model and Hashin-Shtrikman iterative model
Authors: Ke Ganpan , Johnston Merrick , Dong Hefeng
Published: February 2012

Rock-physics modeling of heavy-oil-saturated sands requires adjustments and new approaches to the available fluid-substitution schemes used on conventional reservoirs. This paper introduces two models: the fractional-gradient model (FGM) for simulating the frequency dispersion of the shear modulus of pure bitumen and the Hashin-Shtrikman iterative model (HSIM) for modeling the moduli of bitumen-saturated sands as a function of frequency and temperature. Taylor expansion shows that the first-order FGM has higher resolution than the Maxwell model and lower complexity than the Cole-Cole model. In addition, FGM is superior to Maxwell and Cole-Cole models in that viscosity modeling does not need to be done prior to shear-modulus modeling. The building of HSIM is based on observations of the microstructure of the bitumen-saturated sands. Three main characteristics in the sands are observed in the simplified model, producing a range of stiff, medium, and soft effective matrices. Bitumen can dominate the matrix as if the quartz grains were suspended in it (soft); quartz grains can surround the bitumen (stiff); and a bitumen layer can form around the quartz grain (medium). The quartz grains are assumed to be statistically spherical. HSIM is obtained by iteratively calculating the HS bounds of the stiff and soft parts of the sands. The measured shear modulus of pure bitumen and bitumen-saturated sands at different frequencies and temperatures verify the validity of these two models. The combination of these two models gives a novel fluid-substitution routine for modeling the time-lapse response during steam-assist gravity draining thermal production of bitumen. The limitations of the two models also are discussed.
The hypoblast (visceral endoderm): an evo-devo perspective
Authors: Stern Claudio D. , Downs Karen M.
Published: February 2012

When amniotes appeared during evolution, embryos freed themselves from intracellular nutrition; development slowed, the mid-blastula transition was lost and maternal components became less important for polarity. Extra-embryonic tissues emerged to provide nutrition and other innovations. One such tissue, the hypoblast (visceral endoderm in mouse), acquired a role in fixing the body plan: it controls epiblast cell movements leading to primitive streak formation, generating bilateral symmetry. It also transiently induces expression of pre-neural markers in the epiblast, which also contributes to delay streak formation. After gastrulation, the hypoblast might protect prospective forebrain cells from caudalizing signals. These functions separate mesendodermal and neuroectodermal domains by protecting cells against being caught up in the movements of gastrulation.
RIPPLY3 is a retinoic acid-inducible repressor required for setting the borders of the pre-placodal ectoderm
Authors: Janesick Amanda , Shiotsugu Jason , Taketani Mao , Blumberg Bruce
Published: February 2012

Retinoic acid signaling is a major component of the neural posteriorizing process in vertebrate development. Here, we identify a new role for the retinoic acid receptor (RAR) in the anterior of the embryo, where RAR regulates Fgf8 expression and formation of the pre-placodal ectoderm (PPE). RARα2 signaling induces key pre-placodal genes and establishes the posterolateral borders of the PPE. RAR signaling upregulates two important genes, Tbx1 and Ripply3, during early PPE development. In the absence of RIPPLY3, TBX1 is required for the expression of Fgf8 and hence, PPE formation. In the presence of RIPPLY3, TBX1 acts as a transcriptional repressor, and functions to restrict the positional expression of Fgf8, a key regulator of PPE gene expression. These results establish a novel role for RAR as a regulator of spatial patterning of the PPE through Tbx1 and RIPPLY3. Moreover, we demonstrate that Ripply3, acting downstream of RAR signaling, is a key player in establishing boundaries in the PPE.
Samp1 is a component of TAN lines and is required for nuclear movement
Authors: Borrego-Pinto Joana , Jegou Thibaud , Osorio Daniel S. , Auradé Frederic , Gorjánácz Mátyás , Koch Birgit , Mattaj Iain W. , Gomes Edgar R.
Published: February 2012

The position of the nucleus is regulated in different developmental stages and cellular events. During polarization, the nucleus moves away from the future leading edge and this movement is required for proper cell migration. Nuclear movement requires the LINC complex components nesprin-2G and SUN2, which form transmembrane actin-associated nuclear (TAN) lines at the nuclear envelope. Here we show that the nuclear envelope protein Samp1 (NET5) is involved in nuclear movement during fibroblast polarization and migration. Moreover, we demonstrate that Samp1 is a component of TAN lines that contain nesprin-2G and SUN2. Finally, Samp1 associates with SUN2 and lamin A/C, and the presence of Samp1 at the nuclear envelope requires lamin A/C. These results support a role for Samp1 in the association between the LINC complex and lamins during nuclear movement.