bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival of Clavibacter michiganensis subsp. michiganensis in tomato debris under greenhouse conditions
Authors: Vega D. , Romero A. M.
Published: August 2015

Bacterial canker, caused by Clavibacter michiganensis subsp. michiganensis, is one of the most important diseases of tomato worldwide. Once the pathogen has been introduced into an area, i.e. by contaminated seeds or transplants, it survives mainly on host debris. In different geographic areas the survival time of the pathogen in crop residues under field conditions has been very variable, ranging from 2 months in Morocco to 2 years in Iowa (USA). This study took place in the horticultural belt of Buenos Aires – La Plata, Argentina, where greenhouse production prevails, and monoculture with two production cycles per year is a common practice. The aim was to determine the survival time of this pathogen in plant residues left on the soil surface or buried. During three consecutive years, by the end of both production cycles in July (winter) and December (summer), above‐ (stem, petiole) and belowground (root) tissues were placed into nylon netting bags and left on the soil surface or buried at 10 cm depth. The pathogen population was regularly quantified by dilution plating on semiselective medium. In host debris left on the soil surface, bacteria survived 120–260 days for crop production cycles that ended in winter and 45–75 days for those that ended in summer. In stems or roots buried in winter, this period was 45–75 days. It is concluded that host debris, including roots, might be an important primary inoculum source of the pathogen in greenhouses.
Fusarium oxysporum f. sp. radicis‐vanillae is the causal agent of root and stem rot of vanilla
Authors: Koyyappurath S. , Atuahiva T. , Le Guen R. , Batina H. , Le Squin S. , Gautheron N. , Edel Hermann V. , Peribe J. , Jahiel M. , Steinberg C. , Liew E. C. Y. , Alabouvette C. , Besse P. , Dron M. , Sache I. , Laval V. , Grisoni M.
Published: August 2015

Root and stem rot (RSR) is a very detrimental disease of vanilla worldwide. Fusarium oxysporum is frequently associated with the disease but other Fusarium species are also reported. In this international study, 52 vanilla plots were surveyed in three of the most important vanilla producing countries (Madagascar, Reunion Island and French Polynesia) in order to determine the aetiology of RSR disease. Subsets from the 377 single‐spored Fusarium isolates recovered from rotten roots and stems in the surveys were characterized by molecular genotyping (EF1α and IGS gene sequences) and pathogenicity assays on Vanilla planifolia and V. ×tahitensis, the two commercially grown vanilla species. Fusarium oxysporum was shown to be the principal species responsible for the disease, representing 79% of the isolates recovered from the RSR tissues, 40% of which induced severe symptoms on inoculated plantlets. Fusarium oxysporum isolates were highly polyphyletic regardless of geographic origin or pathogenicity. Fusarium solani, found in 15% of the samples and inducing only mild symptoms on plantlets, was considered a secondary pathogen of vanilla. Three additional Fusarium species were occasionally isolated in the study (F. proliferatum, F. concentricum and F. mangiferae) but were nonpathogenic. Histopathological preparations observed in wide field and multiphoton microscopy showed that F. oxysporum penetrated the root hair region of roots, then invaded the cortical cells where it induced necrosis in both V. planifolia and V. ×tahitensis. The hyphae never invaded the root vascular system up to 9 days post‐inoculation. As a whole, the data demonstrated that RSR of vanilla is present worldwide and that its causal agent should be named F. oxysporum f. sp. radicis‐vanillae.
Effect of Testosterone Administration and Spiking on Reproductive Success of Broiler Breeder Flocks
Authors: Ordas B , Vahedi S , Seidavi A , Rahati M , Laudadio V , Tufarelli V
Published: August 2015

Contents

Age negatively affects reproductive success of broiler breeder flocks. One of the main hormones involved in the change of fertility with the age is testosterone (TT). The introduction of young males at later production stages of broiler flocks is known as spiking and is expected to reduce the fertility decline with age. The aim of this study was to determine the effect of injection of different levels of TT and the effect of spiking on reproductive fitness of broiler breeder flocks. Two experiments were conducted on Ross 308 breeder flocks for 10 weeks (41–50 weeks of age). The experiment 1 included a control and three treatments corresponding to three doses of TT (0.1, 0.2 and 0.3 cc), while the experiment 2 included a control and one treatment corresponding to spiking. The lower dose of TT (0.1 cc) and the spiking clearly slowed down the decline in hatchability. Therefore, either the external administration of TT to the males when the natural concentration of TT starts to decline or spiking the breeder flock with young roosters could contribute to improve reproductive success in later stages of the production cycle in broiler breeder flocks.
Modeling Lung Carcinogenesis in Radon‐Exposed Miner Cohorts: Accounting for Missing Information on Smoking
Authors: van Dillen Teun , Dekkers Fieke , Bijwaard Harmen , Brüske Irene , Wichmann H.‐Erich , Kreuzer Michaela , Grosche Bernd
Published: August 2015

Epidemiological miner cohort data used to estimate lung cancer risks related to occupational radon exposure often lack cohort‐wide information on exposure to tobacco smoke, a potential confounder and important effect modifier. We have developed a method to project data on smoking habits from a case‐control study onto an entire cohort by means of a Monte Carlo resampling technique. As a proof of principle, this method is tested on a subcohort of 35,084 former uranium miners employed at the WISMUT company (Germany), with 461 lung cancer deaths in the follow‐up period 1955–1998. After applying the proposed imputation technique, a biologically‐based carcinogenesis model is employed to analyze the cohort's lung cancer mortality data. A sensitivity analysis based on a set of 200 independent projections with subsequent model analyses yields narrow distributions of the free model parameters, indicating that parameter values are relatively stable and independent of individual projections. This technique thus offers a possibility to account for unknown smoking habits, enabling us to unravel risks related to radon, to smoking, and to the combination of both.
Tumour, Oxidative Stress and Host T Cell Response: Cementing the Dominance
Authors: Bhattacharyya S. , Saha J.
Published: August 2015

Reactive oxygen species (ROS) and free radicals are produced intrinsically during normal cellular metabolic processes or extrinsically due to ionizing radiations, UV rays, xenobiotic insult, etc. ROS are important signal mediators and are used by the immune system to destroy pathogens, but as these are highly reactive, they also have the capacity to cause DNA damage and alter protein and lipid components of a cell. As a result, cells have evolved a tight regulation of internal redox environment that involves a balanced interplay between free radicals produced and quenched by cellular antioxidants and enzyme systems. Any deregulation of this subtle balance can result in oxidative stress that can lead to various pathological conditions including cancer. Oxidative stress can be a cause of neoplasia, or it can be induced by a growing tumour itself. The link existing between oxidative stress and inflammation is also very strong. Suppressed cellular immune system, especially effector T cell system, is a characteristic of tumour‐bearing host. Both the direct oxidative stress caused by tumour cell(s) and oxidative stress mediators present in tumour microenvironment play a significant role in the suppression of effector T cell function and induction of T cell death. This review discusses in detail the complex interplay between tumour–stroma–immune system in the light of oxidative stress that dominates every phase of cancer including initiation, progression and establishment. This review also addresses in detail the mechanisms of oxidative stress‐induced T cell dysfunction in tumour‐bearing host and also briefly points out the possible therapeutic interventions.
Immunization with Single Oral Dose of Alginate‐Encapsulated BCG Elicits Effective and Long‐Lasting Mucosal Immune Responses
Authors: Hosseini M. , Dobakhti F. , Pakzad S. R. , Ajdary S.
Published: August 2015

Effective vaccination against pathogens, which enter the body through mucosal surfaces, requires the induction of both mucosal and systemic immune responses. Here, mucosal as well as systemic immune responses in the lung and spleen of BALB/c mice which were orally vaccinated with a single dose of alginate‐encapsulated bacille Calmette–Guerin (BCG) were evaluated. Twenty weeks after immunization, the vaccinated mice were challenged intranasally with BCG. Twelve weeks after immunization and 5 weeks after challenge, the immune responses were evaluated. Moreover, immune responses were compared with those of mice that were vaccinated with free BCG by subcutaneous (sc) and oral routes. Twelve weeks after the immunization, serum IgG level was higher in the sc‐immunized mice, while serum IgA level was higher in the orally immunized mice with encapsulated BCG. Significant productions of both IgG and IgA were only detected in lungs of mice orally immunized with encapsulated BCG. Proliferative and delayed‐type hypersensitivity responses and IFN‐γ production were significantly higher in mice immunized orally with encapsulated BCG, compared to mice immunized orally with free BCG. After challenge, the levels of IFN‐γ were comparable between sc‐immunized mice with free BCG and orally immunized with encapsulated BCG; however, significantly less IL‐4 was detected in mice which had received encapsulated BCG via oral route. Moreover, significant control of the bacilli growth in the lung of the immunized mice after intranasal challenge with BCG was documented in mice vaccinated with encapsulated BCG. These results suggest that oral immunization with alginate‐encapsulated BCG is an effective mean of inducing mucosal and systemic specific immune responses.
Upregulation of HO‐1 with Haemin Alleviates LPS‐Stimulated Pro‐inflammatory Responses Through Downregulation of p38 Signalling Pathways in Rat Liver
Authors: Tang J. , Li L. , Li C.‐M. , Wu J. , Sun Y. , Wang G.‐L.
Published: August 2015

Haem oxygenase‐1 (HO‐1) plays an important role in inflammatory disease development and progression. Whether it has an anti‐inflammatory role in lipopolysaccharide (LPS)‐induced liver injury remains unclear. To investigate the functional role of HO‐1 in protecting liver tissue against inflammatory response stimulated by LPS in rat and the mechanism by which it achieves this protective effect, LPS‐stimulated inflammatory models were established. In pretreatment of rats with HO‐1 activator (haemin) or inhibitor (zinc protoporphyrin‐9, ZnPP, a specific inhibitor of HO) before LPS stimulation, we evaluated the pathological changes by haematoxylin–eosin staining. The mRNA expression and secretion of IL‐1β and IL‐6 in rat liver were analysed using the real‐time PCR and ELISA. Real‐time PCR and Western blot were also used to evaluate the expression of HO‐1, p38 and p‐p38 in liver. Liver CO contents were sensitized to the expression of HO‐1. Induction of HO‐1 by haemin remarkably inhibited the expression of p38, and addition of ZnPP increased this expression. Our results demonstrate that HO‐1 is an anti‐inflammation factor in LPS‐stimulated liver, which regulate the inflammatory response through downregulation of p38 signalling pathways in rat liver.
Ethnicity as a Variable: An Assessment of Measures and Data Sets of Ethnicity and Related Identities*
Authors: Marquardt Kyle L. , Herrera Yoshiko M.
Published: August 2015

Objective

With the proliferation of new data sets and measures of identity‐based diversity, especially regarding ethnicity, it is essential that scholars who use these data sets on “ethnicity” understand their theoretical underpinnings, as well as their points of convergence and divergence.

Methods

We conduct a review of existing cross‐national measures of ethnic diversity.

Results

Different data sets involve inclusion boundaries for groups that vary drastically, and operationalize the relationship between the enumerated groups and outcomes of interest in ways that have often unacknowledged theoretical implications.

Conclusions

We describe the advantages and disadvantages of different data sets, and build on this description to point toward future directions in assessing the relationship between diversity and social phenomena, specifically focusing on the mechanisms that link groups to these outcomes. We also provide appendices listing the data sets discussed in the article, enabling scholars to conveniently access them.
Methodological Problems in the Study of Nation‐Building: Behaviorism and Historicist Solutions in Political Science*
Authors: Mylonas Harris
Published: August 2015

Objective

The goal of this article is to highlight the methodological problems involved in the study of nation‐building and propose solutions. I identify three categories of methodological problems that flow from respective practices in social science research: (i) inferring intentions from observed behavior or outcomes; (ii) relying on census data to infer a country's ethnic diversity; and (iii) arbitrary periodization and anachronism, that is, attributing certain actions to concepts and/or phenomena that were not politically salient or even understood by the actors under study.

Methods

I conduct a meta‐analysis of the body of evidence I used in my recent work, which systematically documents nation‐building policies toward noncore groups in the post World War I Balkans.

Results

In each section, I use empirical examples to illustrate the methodological pitfalls that may result from these practices and suggest strategies to overcome these difficulties.

Conclusion

Certain applications of behaviorism can lead to wrongheaded theories and introduce bias in our analysis. Needless to say, these problems are not unique to the study of nation‐building. Scholars are invited to adopt historicist solutions to these problems.
The Asymmetry of Nationalist Exclusion and Inclusion: Migration Policy Preferences in Russia, 2005–2013*
Authors: Alexseev Mikhail
Published: August 2015

Objective

The study investigates sources of asymmetry between individual attitudes toward nationalist inclusion and exclusion—focusing on why public support in Russia for deporting all migrants remained about the same from 2005 to 2013, while support for admitting all migrants significantly declined.

Methods

Data from surveys based on multistage random sampling of the adult population of the Russian Federation in 2005 (N= 579) and 2013 (N= 805) are subjected to multiple (OLS) regression analysis, in which support for deportation and admission of migrants are dependent variables and survey measures (with different specifications) of intergroup threat, competition, bias, contact, and the immigration security dilemma, as well as education and media exposure are the independent variables.

Results

Only two predictors consistently explained support for both inclusion and exclusion of migrants in Russia in both 2005 and 2013—perceived state strength and economic vulnerability. In every test, support for exclusion nonrandomly related to more predictors in the same model than support for inclusion.

Conclusion

In changing political and socioeconomic contexts exclusionist views are more persistent than inclusive views. Both measures need to be used in research on intergroup relations and nationalism. Otherwise, one is more likely to accept false positives while underestimating some significant enduring predictors.
The Construction of National Identity and its Challenges in Post‐Yugoslav Censuses*
Authors: Bieber Florian
Published: August 2015

Objectives

To understand the politics of population census in postconflict countries and salience of the categories imposed through census. By doing so, it seeks to shed light on the mechanisms of identity construction in the post‐Yugoslav context.

Methods

The article analyzes the categories and the responses to post‐Yugoslav censuses, focusing on national, religious, and linguistic identity markers.

Results

The analysis shows that a varying, yet significant, share of the population refuses to identify according to the identity markers proposed by the state and promoted by key political actors.

Conclusion

The article proposes a novel way of studying censuses and argues that even in a postconflict context national identities are less fixed than often supposed and highlights the need to focus more on nonconformist identities in postconflict settings.
E3 ubiquitin ligase gene CMPG1–V from Haynaldia villosa L. contributes to powdery mildew resistance in common wheat (Triticum aestivum L.)
Authors: Zhu Yanfei , Li Yingbo , Fei Fei , Wang Zongkuan , Wang Wei , Cao Aizhong , Liu Yuan , Han Shuang , Xing Liping , Wang Haiyan , Chen Wei , Tang Sanyuan , Huang Xiahe , Shen Qianhua , Xie Qi , Wang Xiue
Published: August 2015

Powdery mildew is one of the most devastating wheat fungal diseases. A diploid wheat relative, Haynaldia villosa L., is highly resistant to powdery mildew, and its genetic resource of resistances, such as the Pm21 locus, is now widely used in wheat breeding. Here we report the cloning of a resistance gene from H. villosa, designated CMPG1–V, that encodes a U–box E3 ubiquitin ligase. Expression of the CMPG1–V gene was induced in the leaf and stem of H. villosa upon inoculation with Blumeria graminis f. sp. tritici (Bgt) fungus, and the presence of Pm21 is essential for its rapid induction of expression. CMPG1–V has conserved key residues for E3 ligase, and possesses E3 ligase activity in vitro and in vivo. CMPG1–V is localized in the nucleus, endoplasmic reticulum, plasma membrane and partially in trans‐Golgi network/early endosome vesicles. Transgenic wheat over‐expressing CMPG1–V showed improved broad‐spectrum powdery mildew resistance at seedling and adult stages, associated with an increase in expression of salicylic acid‐responsive genes, H2O2 accumulation, and cell‐wall protein cross‐linking at the Bgt infection sites, and the expression of CMPG1–V in H. villosa was increased when treated with salicylic acid, abscisic acid and H2O2. These results indicate the involvement of E3 ligase in defense responses to Bgt fungus in wheat, particularly in broad‐spectrum disease resistance, and suggest association of reactive oxidative species and the phytohormone pathway with CMPG1–V‐mediated powdery mildew resistance.
An Analysis of the Potential of Manufacturing and Services Sectors as Drivers of Economic Growth and Development in Namibia
Authors: Chifamba Ronald T. , Odhiambo Ojijo
Published: August 2015

The purpose of this paper is to analyse the potential of the manufacturing and services sectors as drivers of economic growth in Namibia. The paper uses the intersectoral linkage analysis method to identify the industries with the greatest backward and forward linkages. The economy-wide impact of these industries is simulated further using a CGE model. The greatest backward linkages for manufacturing industries were found in meat processing, fish processing, grain milling, basic metals and construction. The greatest backward linkages for the tertiary industries were found in trade and repairs, hotels and restaurants, finance and insurance, and other private services. The greatest forward linkages for manufacturing industries were found in paper and printing, chemicals and rubber, fabricated metals and machinery, and electricity generation and distribution. The greatest forward linkages for tertiary industries were found in transport, communication, finance and insurance, and market real estate and business services. These, therefore, are the sectors that policies could target as they have greatest impact and could enable Namibia to achieve higher levels of growth. Further, simulation results are obtained from a CGE model by introducing direct exogenous increases in the output of the perceived key industries and examining the economy-wide feedback effects.
Biomechanical Analysis of a Dynamic Stability Test System to Evoke Sway and Step Recovery
Authors: Gildenhuys Anne , Zandiyeh Payam , Kuntze Gregor , Goldsmith Peter , Ronsky Janet L.
Published: August 2015

This paper reports on the dynamic analysis and experimental validation of a method to perturb the balance of subjects in quiet standing. Electronically released weights pull the subject's waist through a specified displacement sensed by a photoelectric sensor. A dynamic model is derived that computes the force applied to the subject as a function of waist acceleration. This model accurately predicts the acceleration of mock subjects (suspended masses) with high repeatability. The validity and simplicity of this model suggest that this method can provide a standard for provocation testing on stable surfaces. Proof-of-concept trials on human subjects demonstrate that the device can be used with a force platform and motion tracking and that the device can induce both sway and step recoveries in healthy male adults.
Determination of Force Parameters for Milling Simulations by Combining Optimization and Simulation Techniques
Authors: Freiburg Dennis , Hense Rouven , Kersting Petra , Biermann Dirk
Published: August 2015

Milling is a machining process in which material removal occurs due to the rotary motion of a cutting tool relative to a typically stationary workpiece. In modern machining centers, up to and exceeding six degrees of freedom for motion relative to the tool and workpiece are possible, which results in a very complex chip and force formation. For the process layout, simulations can be used to calculate the occurring process forces, which are needed, e.g., for the prediction of surface errors of the workpiece, or for tool wear and process optimization examinations. One limiting factor for the quality of simulation results is the parametrization of the models. The most important parameters for milling simulations are the ones that calibrate the force model, as nearly every modeled process characteristic depends on the forces. This article presents the combination of a milling simulation with the Broyden–Fletcher–Goldfarb–Shanno (BFGS) optimization algorithm for the fast determination of force parameters that are valid for a wide range of process parameters. Experiments were conducted to measure the process forces during milling with different process parameters. The measured forces serve as basis for tests regarding the quality of the determined force parameters. The effect of the tool runout on the optimization result is also discussed, as this may have significant influence on the forces when using tools with more than one tooth. The article ends with a conclusion, in which some notes about the practical application of the algorithm are given.
Dimensional Synthesis of Wristed Binary Hands
Authors: Hassanzadeh Neda , Perez-Gracia Alba
Published: August 2015

The kinematic synthesis applied to tree topologies is a tool for the design of multifingered robotic hands, for a simultaneous task of all fingertips. Even though traditionally wrists and hands have been designed separately, the wrist usually being part of the robot manipulator arm, it makes sense to consider the wrist as a part of the hand, as many grasping and manipulation actions are a coordinated action of wrist and fingers. The manipulation capabilities of robotic hands may also be enhanced by considering more than one splitting stage, as opposed to the single-palm traditional hand. In this work, we present the dimensional synthesis for a family of multifingered hands, the binary hands, which have a 2R wrist and several splitting stages, each of them spanning two branches consisting of a revolute joint for each edge. For these topologies, it is proved that a three-position task can be defined for each fingertip, regardless of the number of fingers. One example is presented to show the possible design strategies and uses for this family of hands.
A High-Resolution Continuous-Scan Acoustic Measurement Method for Turbofan Engine Applications
Authors: Shah Parthiv N. , Vold Håvard , Hensley Dan , Envia Edmane , Stephens David
Published: August 2015

Detailed mapping of the sound field produced by a modern turbofan engine, with its multitude of overlapping noise sources, often requires a large number of microphones to properly resolve the directivity patterns of the constituent tonal and broadband components. This is especially true at high frequencies where the acoustic wavelength is short, or when shielding, scattering, and reflection of the sound field may be present due to installation effects. This paper presents a novel method for measuring the harmonic and broadband content of complex noncompact noise sources using continuously moving (referred to here as continuous-scan (CS)) microphones in conjunction with a state-of-the-art phase-referencing technique. Because the microphones are moving through the sound field produced by the noise sources, they effectively provide infinite spatial resolution of the sound directivity over the scan path. In this method, harmonic (i.e., shaft-coherent) content at the integer multiples of the instantaneous shaft rotational frequency is first extracted from the time signal using a tachometer signal and the Vold-Kalman (VK) filter. The residual broadband signal is then filtered in the time domain in fractional octave bands. The broadband spectra of the signals from the moving microphones are then computed at arbitrary positions along their scan paths using weighted averages (based on Chebyshev polynomial zero-crossings) and the assumption of a complex envelope that varies slowly over a spatial scale whose lower bound is set by the acoustic wavenumber. A benefit of this method is that the decomposition of the total measured sound field into a stochastic superposition of components preserves a meaningful phase definition for each “partial field” associated with a given shaft order (SO). This preservation of phase data enables the forward or backward projection of each of these partial fields using acoustical holography (AH). The benefits of the CS method are demonstrated using acoustic data acquired for a 22-in. scale-model fan stage run at the NASA Glenn Research Center's 9-foot by 15-foot wind tunnel. Two key outcomes of the work include (1) significant improvement in the spatial resolution of the measured sound field and (2) reduction in the overall data acquisition time. Additionally, the methods described here lead to new opportunities for noise source diagnostics and visualization.
Analysis of Measured Flame Transfer Functions With Locally Resolved Density Fluctuation and OH-Chemiluminescence Data
Authors: Peterleithner Johannes , Stadlmair Nicolai V. , Woisetschläger Jakob , Sattelmayer Thomas
Published: August 2015

The goal of this study is to analyze flame transfer functions (FTFs) locally by quantifying the heat release rate with OH*-chemiluminescence and density fluctuation measurements using laser vibrometry. In this study, both techniques are applied to a swirl burner configuration with known FTFs acquired by multimicrophone-method (MMM) measurements for perfectly premixed and partially premixed cases. The planar fields of the quantities are compared to the FTFs in order to improve the understanding regarding the specific amplitude and phase values. On the global scale values of heat release expected from the MMM are satisfactorily reproduced by both methods for the premixed cases, whereas OH*-chemiluminescence data cannot be used as indicator for heat release in the partially premixed case, where equivalence ratio fluctuations are present. Vibrometry is not affected by fluctuations of equivalence ratio but additionally reveals the periodic oscillation of the conical annular jet of the cold reactants in the combustor filled with hot products.
Analysis of the Unstable Behavior of a Pump-Turbine in Turbine Mode: Fluid-Dynamical and Spectral Characterization of the S-shape Characteristic
Authors: Cavazzini Giovanna , Covi Alberto , Pavesi Giorgio , Ardizzon Guido
Published: August 2015

The most common mechanical equipment adopted in the new generation of pumped-hydro power plants is represented by reversible pump-turbines (RPT), required to rapidly switch between pumping and generating modes in order to balance the frequent changes in electricity production and consumption caused by unpredictable renewable energy sources. As a consequence, pump-turbines are required to extend their operation under off-design conditions in unstable operating areas. The paper presents a numerical analysis of the unstable behavior of a pump-turbine operating in turbine mode near the no-load condition. To study in depth the unsteady phenomena which lead to the S-shape of the turbine characteristic, a load rejection scenario at constant and large guide vane opening (GVO) was numerically analyzed by running through the flow-speed characteristic up to the turbine brake region. The flow field analysis led to the onset and development of unsteady phenomena progressively evolving in an organized rotating stall (RS) (65.1% of the runner rotation frequency) during the turbine brake operation. These phenomena were characterized by frequency and time–frequency analyses of several numerical signals (static pressure, blade torque, mass flow rate in blade passages). The influence of the development of these unsteady phenomena on the pump-turbine performance in a turbine operation was also analyzed, and the potential causes that generated the S-shaped characteristic curve were also investigated.
Design of a Compact Biaxial Tensile Stage for Fabrication and Tuning of Complex Micro- and Nano-scale Wrinkle Patterns
Authors: Saha Sourabh K. , Culpepper Martin L.
Published: August 2015

Wrinkling of thin films is a strain-driven process that enables scalable and low-cost fabrication of periodic micro- and nano-scale patterns. In the past, single-period sinusoidal wrinkles have been applied for thin-film metrology and microfluidics applications. However, real-world adoption of this process beyond these specific applications is limited by the inability to predictively fabricate a variety of complex functional patterns. This is primarily due to the inability of current tools and techniques to provide the means for applying large, accurate, and nonequal biaxial strains. For example, the existing biaxial tensile stages are inappropriate because they are too large to fit within the vacuum chambers that are required for thin-film deposition/growth during wrinkling. Herein, we have designed a compact biaxial tensile stage that enables (i) applying large and accurate strains to elastomeric films and (ii) in situ visualization of wrinkle formation. This stage enables one to stretch a 37.5 mm long film by 33.5% with a strain resolution of 0.027% and maintains a registration accuracy of 7 μm over repeated registrations of the stage to a custom-assembled vision system. Herein, we also demonstrate the utility of the stage in (i) studying the wrinkling process and (ii) fabricating complex wrinkled patterns that are inaccessible via other techniques. Specifically, we demonstrate that (i) spatial nonuniformity in the patterns is limited to 6.5%, (ii) one-dimensional (1D) single-period wrinkles of nominal period 2.3 μm transition into the period-doubled mode when the compressive strain due to prestretch release of plasma-oxidized polydimethylsiloxane (PDMS) film exceeds ∼18%, and (iii) asymmetric two-dimensional (2D) wrinkles can be fabricated by tuning the strain state and/or the actuation path, i.e., the strain history. Thus, this tensile stage opens up the design space for fabricating and tuning complex wrinkled patterns and enables extracting empirical process knowledge via in situ visualization of wrinkle formation.
Modeling of the Friction Behavior in Metal Forming Process Considering Material Hardening and Junction Growth
Authors: Mao Mengyun , Peng Linfa , Yi Peiyun , Lai Xinmin
Published: August 2015

In various plastic forming processes of metals, friction has been revealed to play an important role in the determination of the material flow, fracture, and surface quality. The precise description of friction behavior is thus a critical issue for the accurate prediction and analysis of these formability indicators. Generally, the friction behavior is inevitably affected by material hardening and junction growth. However, few of the previous models have taken both of them into consideration, especially for the nonlinear hardening materials. In this study, the classical contact model was modified to include the power-law hardening material, and the general friction law combined with Tabor's equation was employed to estimate the friction stress with the junction growth of asperities. An asperity-based friction model for rough surfaces in metal forming process was then obtained by summarizing the normal and tangential stresses of all the asperities on the surface using Greenwood and Williamson (GW) method. The model was validated by comparing to the finite element (FE) results and the experimental results. And its comparison with Kogut and Etsion (KE) model and Cohen's model revealed a wider range of application for the present model. It was also found to be able to predict the friction coefficient and the real contact area of nonlinear hardening materials under various contact conditions. This work is helpful to understand the friction behavior and further guide the simulation and optimization of forming processes.
Experimental Studies on Foil Bearing With a Sliding Coating Made of Synthetic Material
Authors: Zywica Grzegorz , Baginski Pawel , Banaszek Slawomir
Published: August 2015

The paper discusses the research on foil bearings with antifriction coating manufactured from synthetic materials. The tests were carried out on a special test stand of our own construction, designed with the use of numerical analysis. In the course of the experimental studies, the test stand was set up in two configurations: with one or two foil bearings. The measurements were done, which focused on temperature distributions with the aid of thermocouples and thermovision camera. The measurements were being performed under varying conditions of bearing operation. The conducted experiments permitted to verify the durability, thermal characteristics, and dynamic performance of foil bearings in different configurations. An original method to measure temperature of a top foil has been worked out.
Design and Synthesis of a Geopolymer-Enhanced Quasi-Crystalline Composite for Resisting Wear and Corrosion
Authors: Fevzi Ozaydin M. , Liang Hong
Published: August 2015

Multiphase composites are attractive for improved mechanical performance and corrosion resistance. In this research, a new composite consisting quasi-crystalline Al75Mn14Si7Fe4 alloy of icosahedral, cubic α-AlMnSiFe, monoclinic Al13Fe4 phases, and ferro-silico-aluminate geopolymer was synthesized using rapid solidification and thermal treatment methods. The concentration of icosahedral phase (i-phase) was controlled and the formation of geopolymer was obtained through heat treatment. Characterization showed that the microhardness and wear resistance were increased with the amount of i-phase. The corrosion resistance, on the other hand, was improved with the existence of the geopolymer. This research demonstrates an effective approach in processing a multiphase composite that has desired properties and performance through multiphase design and composition.
Design and Synthesis of a Superhydrophobic PVDF-Based Composite
Authors: Choi Hyunho , Lee Kyungjun , Reeks John , Liang Hong
Published: August 2015

The ability to design, control, and synthesize a material surface with superhydrophobicity is of great interests in many engineering applications. Here, we report a cost-effective process to fabricate poly(vinylidene fluoride) (PVDF)/zirconium(IV) oxide (ZrO2) composites with superhydrophobicity. This is achieved by combining an antisolvent that induces phase separation, i.e., the precipitation of PVDF from the solution through a spray-on method on various liquids. The material surfaces possess wrinkled micron-sized beads which displayed superhydrophobicity in water without any chemical treatment. The process developed in this research presented a fast and simple approach in making hydrophobic surfaces.
A quantification of the effectiveness of EPID dosimetry and software‐based plan verification systems in detecting incidents in radiotherapy
Authors: Bojechko Casey , Phillps Mark , Kalet Alan , Ford Eric C.
Published: August 2015

Purpose:

Complex treatments in radiation therapy require robust verification in order to prevent errors that can adversely affect the patient. For this purpose, the authors estimate the effectiveness of detecting errors with a “defense in depth” system composed of electronic portal imaging device (EPID) based dosimetry and a software‐based system composed of rules‐based and Bayesian network verifications.

Methods:

The authors analyzed incidents with a high potential severity score, scored as a 3 or 4 on a 4 point scale, recorded in an in‐house voluntary incident reporting system, collected from February 2012 to August 2014. The incidents were categorized into different failure modes. The detectability, defined as the number of incidents that are detectable divided total number of incidents, was calculated for each failure mode.

Results:

In total, 343 incidents were used in this study. Of the incidents 67% were related to photon external beam therapy (EBRT). The majority of the EBRT incidents were related to patient positioning and only a small number of these could be detected by EPID dosimetry when performed prior to treatment (6%). A large fraction could be detected by in vivo dosimetry performed during the first fraction (74%). Rules‐based and Bayesian network verifications were found to be complimentary to EPID dosimetry, able to detect errors related to patient prescriptions and documentation, and errors unrelated to photon EBRT. Combining all of the verification steps together, 91% of all EBRT incidents could be detected.

Conclusions:

This study shows that the defense in depth system is potentially able to detect a large majority of incidents. The most effective EPID‐based dosimetry verification is in vivo measurements during the first fraction and is complemented by rules‐based and Bayesian network plan checking.
Correction factor measurements for multiple detectors used in small field dosimetry on the Varian Edge radiosurgery system
Authors: Tanny Sean , Sperling Nicholas , Parsai E. Ishmael
Published: August 2015

Purpose:

Accurate dosimetry of small fields remains a challenge to the clinical physicist. Choosing the appropriate detector and determination of factors continue to be an area of active research. The purpose of this study is to evaluate the output factors for a dedicated stereotactic accelerator using multiple dosimeters designed for use in small fields and evaluate published factors relative to measured values using a commercial scintillating fiber.

Methods:

Four microionization chambers, a commercial plastic scintillation detector, and a semiconducting diode were used to measure output factors for a linear accelerator. Field sizes ranging from 6 × 6 to 0.6 × 0.6 cm2 were measured in a water phantom at 10 cm depth for 100 cm SSD. All microionization chambers were mounted in both vertical and horizontal configurations. Fields were normalized to the output at 5 × 5 cm2. Output correction factors, , were calculated as the ratio of a detector response relative to the scintillating fiber response for a given clinical field size, fclin.

Results:

Ionization chambers consistently under‐responded for small fields relative to the scintillating fiber. Variations in response between horizontal and vertical mounting were most notable for the microchambers, with the vertical mounting which reduced the magnitude of the necessary correction factor, , for the microionization chambers ranging from 1.1 to 1.2 for the smallest field size at all energies. The semiconducting diode over‐responded by 7% for the smallest field size across all energies, resulting in a of ∼0.93.

Conclusions:

The commercial scintillating fiber, which produces accurate and consistent ratios of dose to water for nonstandard fields, can be used to measure correction factors for various detectors used in a clinical setting. This can allow for comparison of measured correction factors to previously published values.
Statistical iterative reconstruction to improve image quality for digital breast tomosynthesis
Authors: Xu Shiyu , Lu Jianping , Zhou Otto , Chen Ying
Published: August 2015

Purpose:

Digital breast tomosynthesis (DBT) is a novel modality with the potential to improve early detection of breast cancer by providing three‐dimensional (3D) imaging with a low radiation dose. 3D image reconstruction presents some challenges: cone‐beam and flat‐panel geometry, and highly incomplete sampling. A promising means to overcome these challenges is statistical iterative reconstruction (IR), since it provides the flexibility of accurate physics modeling and a general description of system geometry. The authors’ goal was to develop techniques for applying statistical IR to tomosynthesis imaging data.

Methods:

These techniques include the following: a physics model with a local voxel‐pair based prior with flexible parameters to fine‐tune image quality; a precomputed parameter λ in the prior, to remove data dependence and to achieve a uniform resolution property; an effective ray‐driven technique to compute the forward and backprojection; and an oversampled, ray‐driven method to perform high resolution reconstruction with a practical region‐of‐interest technique. To assess the performance of these techniques, the authors acquired phantom data on the stationary DBT prototype system. To solve the estimation problem, the authors proposed an optimization‐transfer based algorithm framework that potentially allows fewer iterations to achieve an acceptably converged reconstruction.

Results:

IR improved the detectability of low‐contrast and small microcalcifications, reduced cross‐plane artifacts, improved spatial resolution, and lowered noise in reconstructed images.

Conclusions:

Although the computational load remains a significant challenge for practical development, the superior image quality provided by statistical IR, combined with advancing computational techniques, may bring benefits to screening, diagnostics, and intraoperative imaging in clinical applications.
Frequency‐specific functional connectivity revealed by wavelet‐based coherence analysis in elderly subjects with cerebral infarction using NIRS method
Authors: Tan Qitao , Zhang Ming , Wang Yi , Zhang Manyu , Wang Yan , Xin Qing , Wang Bitan , Li Zengyong
Published: August 2015

Purpose:

Resting‐state functional connectivity in subjects with cerebral infarction (CI) was assessed using wavelet‐based coherence analysis of near‐infrared spectroscopy (NIRS) signals.

Methods:

Continuous recordings of NIRS signals were measured from the prefrontal cortex and sensorimotor cortical areas of 12 subjects with CI (CI group) and 16 healthy subjects (healthy group) during the resting state. The channels in these areas were divided into four connection types: homologous connectivity, frontoposterior connectivity, contralateral connectivity, and homolateral connectivity. Wavelet coherence (WCO) and wavelet phase coherence (WPCO) were calculated in six frequency intervals in each channel pair: I, 0.6–2 Hz; II, 0.145–0.6 Hz; III, 0.052–0.145 Hz; IV, 0.021–0.052 Hz; V, 0.0095–0.021 Hz; and VI, 0.005–0.0095 Hz.

Results:

WCO in the six frequency intervals was significant for all channels in the healthy group. By contrast, WCO in frequency intervals II–VI showed weakened connectivity in the CI group, especially in terms of frontoposterior connectivity. WCO was significantly lower in the CI group than in the healthy group in the following connectivities and frequency intervals: front‐posterior, IV–VI (p < 0.05); homologous, III–V (p < 0.01); motor‐contralateral, III–V (p < 0.05); and motor‐homolateral, III–V (p < 0.05). WPCO in frequency intervals III (F = 5.032, p = 0.033) and IV (F = 11.95, p = 0.002) in frontoposterior connectivity, as well as in intervals III–V in homologous, motor‐contralateral and motor‐homolateral connectivities were significantly lower (p < 0.05) in the CI group than in the healthy group. However, WPCO in interval I showed significantly higher levels in motor‐homolateral connectivity in the CI group than in the healthy group (F = 4.241, p = 0.049).

Conclusions:

The authors’ results suggest that CI causes a frequency‐specific disruption in resting‐state connectivity. This may be useful for assessing the effectiveness of functional recovery after CI.
Demonstrating Fluorescence with Neon Paper and Plastic
Authors: Birriel Jennifer J. , Roe Clarissa
Published: August 2015

Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and office supply stores. We also employ violet-blue and green laser pointers as excitation sources. We conclude with a brief discussion of neon pigments in terms of the “day glow” or “daylight fluorescence” phenomenon.
Talker-specific influences on phonetic category structure
Authors: Theodore Rachel M. , Myers Emily B. , Lomibao Janice A.
Published: August 2015

A primary goal for models of speech perception is to describe how listeners achieve reliable comprehension given a lack of invariance between the acoustic signal and individual speech sounds. For example, individual talkers differ in how they implement phonetic properties of speech. Research suggests that listeners attain perceptual constancy by processing acoustic variation categorically while maintaining graded internal category structure. Moreover, listeners will use lexical information to modify category boundaries to learn to interpret a talker's ambiguous productions. The current work examines perceptual learning for talker differences that signal well-defined, unambiguous category members. Speech synthesis techniques were used to differentially manipulate talkers' characteristic productions of the stop voicing contrast for two groups of listeners. Following exposure to the talkers, internal category structure and category boundary were examined. The results showed that listeners dynamically adjusted internal category structure to be centered on experience with the talker's voice, but the category boundary remained fixed. These patterns were observed for words presented during training as well as novel lexical items. These findings point to input-driven constraints on functional plasticity within the language architecture, which may help to explain how listeners maintain stability of linguistic knowledge while simultaneously demonstrating flexibility for phonetic representations.
Working stiff: How obesity boosts cancer risk
Authors: Arendt Lisa M. , Kuperwasser Charlotte
Published: August 2015

Obesity promotes breast cancer by enhancing the stiffness of breast adipose tissue through changes in the extracellular matrix (Seo
et al
., this issue).
Contagious biomaterials
Authors: Spiller Kara L.
Published: August 2015

Surface-engineered biomaterials and cells mimic the tolerance-promoting properties of regulatory T cells.