bluuebunny/crossref_metadata_2025 huggingface dataset:
Aging under stress and mechanical fragility of soft solids of laponite
Authors: Reddy G. Ranjith K. , Joshi Yogesh M.
Published: November 2008

In this work, we investigate the aging behavior of soft glassy solids of aqueous suspension of laponite under shear flow. We observe that when an imposed time is normalized by a dominating relaxation time of the system, the rheological response at different ages shows superposition. Analysis of this behavior suggests that the structural evolution with age under a deformation field, as represented by the dependence of dominant relaxation mode on age, becomes weaker as the system becomes progressively less homogeneous due to enhanced attractive interactions caused by addition of salt. Creep-recovery behavior at same elastic modulus shows more viscous dissipation for a system having more salt, demonstrating increase in the mechanical fragility. This study shows that an increase in the concentration of salt, which enhances attractive interactions and causes greater inhomogeneity, leads to a state wherein the particles are held together by weaker interactions. This work leads to important insights into how microstructure affects the aging dynamics. We discuss the observed behavior in the context of aging in colloidal glasses and gels of aqueous suspension of laponite.
Micro-current attenuation modeling and numerical simulation for cage-like ZnO/SiO2 nanocomposite
Authors: Fang Xiao-Yong , Shi Xiao-Ling , Cao Mao-Sheng , Yuan Jie
Published: November 2008

Based on the microwave absorption properties and the micro-current attenuation mechanism for the cage-like ZnO/SiO2 nanocomposite reported in our previous paper, we established a micro-current attenuation model and the associated quantitative formula for the calculation of microwave absorption properties. Very good correlation between the calculated and the experimental results has been obtained for a broad range of frequencies. The maximum deviation less than 3 dB in X-band was obtained. The model provides useful information for understanding the microwave absorption mechanism.
Internal stresses in TiN/Ti multilayer coatings deposited by large area filtered arc deposition
Authors: Cheng Y. H. , Browne T. , Heckerman B. , Jiang J. C. , Meletis E. I. , Bowman C. , Gorokhovsky V.
Published: November 2008

A series of TiN/Ti multilayer coatings with fixed TiN layer thickness and different Ti layer thicknesses were deposited using a large area filtered arc deposition technique. X-ray diffraction was used to investigate the crystalline structure, lattice strain, and crystallinity of the deposited coatings. A substrate curvature method was used to measure the internal stress in the multilayer coatings. The influence of the Ti interlayer thickness on the crystalline structure and internal stress in the coatings was systematically studied. It was found that a cubic TiN phase and hexagonal Ti phase exist in all the multilayer coatings. The TiN and Ti layers in the multilayer coatings exhibit a strong (111) and (002) preferred orientation, respectively. With the increase in the Ti layer thickness, the d-spacing decreases and the peak width increases for both TiN (111) and Ti (002) peaks, indicating a decrease in the lattice strain and an increase in the crystallinity of both TiN and Ti phases. It is suggested, that the reduction in the defect density in both TiN and Ti layers and the relaxation of the stain by the diffusion of the Ti atoms in the underneath Ti layer contribute to the decrease in the total internal stress with increasing Ti layer thickness.
Charge extraction analysis of charge carrier densities in a polythiophene/fullerene solar cell: Analysis of the origin of the device dark current
Authors: Shuttle C. G. , Maurano A. , Hamilton R. , O’Regan B. , de Mello J. C. , Durrant J. R.
Published: November 2008

We demonstrate the use of a simple charge extraction measurement to determine the charge carrier densities n in annealed poly(3-hexylthiophene):methanofullerene solar cells under operating conditions. By applying charge extraction to the device under forward bias in the dark (Jdark), we find Jdark∝n2.6. This dependence on charge density is the same as that we find for bimolecular recombination losses observed in such devices under irradiation at open circuit, suggesting that the dark current originates from bimolecular recombination at the polymer/fullerene interface.
Small divergence edge-emitting semiconductor lasers with two-dimensional plasmonic collimators
Authors: Yu Nanfang , Blanchard Romain , Fan Jonathan , Capasso Federico , Edamura Tadataka , Yamanishi Masamichi , Kan Hirofumi
Published: November 2008

Using quantum cascade lasers with a two-dimensional metallic aperture-grating structure defined on the facet the authors demonstrate a collimated laser beam with small divergence angle perpendicular and parallel to the laser waveguide layers (2.7° and 3.7°, respectively). These values represent a reduction by a factor of ∼30 and ∼10, respectively, compared to those of the original 8.06-μm- wavelength laser without plasmonic collimation. The devices preserve good room temperature performance with output power as high as 53% of that of the original unpatterned lasers.
The giant anisotropic magnetocaloric effect in DyAl2
Authors: von Ranke P. J. , de Oliveira N. A. , Plaza E. J. R. , de Sousa V. S. R. , Alho B. P. , Carvalho A. Magnus G. , Gama S. , Reis M. S.
Published: November 2008

We report on calculations of the anisotropic magnetocaloric effect in DyAl2 using a model Hamiltonian including crystalline electrical field effects. The anisotropic effect is produced by the rotation of a constant magnetic field from the easy to a hard magnetic direction in the crystal and is enhanced by the first order nature of the field induced spin reorientation transition. The calculated results indicate that for a field with modulus of 2 T rotating from a hard to the easy direction, the isothermal magnetic entropy (ΔSiso) and adiabatic temperature (ΔTad) changes present peak values higher than 60% the ones observed in the usual process, in which the field direction is kept constant and the modulus of the field is varied.
Molecular beam epitaxy growth of wurtzite AlN nanotips
Authors: Hsu Kuang-Yuan , Liu Chuan-Pu , Chung Hung-Chin , Chiu Yu-Chen
Published: November 2008

The characteristics of structure and morphology of AlN nanotips grown under higher V/III ratio on Si (111) with plasma-assisted molecular beam epitaxy are herein investigated. We found that the AlN nanotips were single crystalline with {1-211} inclined facets and embedded in pitlike defects of N-polarity. The density and size of the AlN nanotips can be controlled by the growth conditions. The AlN nanotip growth mechanism can be rationalized as the c-type dislocations generated between two adjacent grains due to the formation of higher strain area in the early stages of growth. The c-type dislocation would reverse the stacking sequence of the following adatoms, leading to the AlN nanotip growth with inverse polarity and higher growth rate compared to the surrounding matrix. These nanotips might serve as the ideal templates for further growth of nanostructure devices.
Big changes may loom for small business research program
Authors: Kramer David
Published: November 2008

Congress weighing more funding for grants program and letting in venture-capital-controlled companies.
Mishap shuts down LHC until April
Authors: Schwarzschild Bertram
Published: November 2008

Damage to the Large Hadron Collider’s magnets by an electrical fault and by the subsequent helium-vessel rupture is still to be assessed.
Europe sets priorities in astroparticle physics
Authors: Feder Toni
Published: November 2008

Increased funding and global cooperation are key to realizing a wish list of astroparticle physics experiments unveiled this fall.
The physics of networks
Authors: Newman Mark
Published: November 2008

Statistical analysis of interconnected groups—of computers, animals, or people—yields important clues about how they function and even offers predictions of their future behavior.
Rare isotopes in the cosmos
Authors: Schatz Hendrik
Published: November 2008

Such stellar processes as heavy-element formation and x-ray bursts are governed by unstable nuclear isotopes that challenge theorists and experimentalists alike.
On ships, trains, and the equation of time
Authors: Sajina Anna
Published: November 2008

Because of Earth’s elliptical orbit, tilted axis, and standardized time zones, high noon as measured by a clock does not coincide with the Sun’s apex in the sky.
Sociodynamic Discrete Choice on Networks in Space: Impacts of Agent Heterogeneity on Emergent Outcomes
Authors: Dugundji Elenna R , Gulyás László
Published: November 2008

The reported research treats interactions between households and generated feedback dynamics in the adoption of various transportation mode alternatives. We consider a model in which an agent's choice is directly influenced by the percentages of the agent's neighbors and socioeconomic peers that make each choice. The model also accounts for shared unobserved attributes of the choice alternatives in the error structure. We address nonglobal interactions explicitly within different social and spatial network structures, combining advanced econometric estimation with computational techniques from multiagent-based simulation, and we present an empirical application of the model using pseudo-panel microdata collected by the Amsterdam Agency for Traffic, Transport and Infrastructure. Additional heterogeneity is introduced in the model through different mechanisms, such as individual-specific sociodemographic characteristics of the agents, individual-specific attributes of the choice alternatives, and the availability of alternatives. We conclude by highlighting limitations of our present study and recommendations for future work.
5-Pyrrolidin-2-yltetrazole-Promoted One-Pot Hantzsch Polyhydroquinoline Synthesis Using NH4HCO3 as Nitrogen Source
Authors: Su Weike , Li Jia , Li Jianjun
Published: November 2008

A straightforward and green synthesis of polyhydroquinoline derivatives was reported via a four-component coupling reaction of aldehydes, dimedone, active methylene compounds, and ammonium bicarbonate in the presence of 5-pyrrolidin-2-yltetrazole under solvent-free conditions. The method offers several advantages including high yields, an environmental friendly procedure, a short reaction time, and easy isolation of products.
Another View: In Defense of Vigor over Rigor in Classroom Demonstrations
Authors: Dunn Dana S.
Published: November 2008

Scholarship of teaching and learning (SoTL) demands greater empirical rigor on the part of authors and the editorial process than ever before. Although admirable and important, I worry that this increasing rigor will limit opportunities and outlets for a form of pedagogical vigor—the publication of simple, experiential, but empirically unvalidated classroom demonstrations. I explain my concerns, offer reasons why validation is not always possible, discuss possible critiques of my position, and close with suggestions and a modest plea for maintaining this alternative form of SoTL.
The State of the Scholarship of Teaching and Learning in Psychology
Authors: Gurung Regan A. R. , Ansburg Pamela I. , Alexander Patricia A. , Lawrence Natalie Kerr , Johnson David E.
Published: November 2008

Many members of the academy have tried to broaden the construct of scholarship to include activities that investigate pedagogy and student learning, the scholarship of teaching and learning (SoTL). Halpern et al. (1998) first established such a definition for the field of psychology. This article reports on a Society for the Teaching of Psychology (APA, Division 2) task force national survey assessing the state of SoTL in psychology. Although psychology has not globally embraced SoTL as legitimate scholarship, there are indications that the sentiment to do so is taking root. We conclude with recommendations about how the discipline can enhance its efforts to promote SoTL.
Using Yes–No Recognition Tests to Assess Student Memory for Course Content
Authors: Smith Dale L. , Barker Lewis
Published: November 2008

We report 3 experiments using yes–no recognition tests of student memory for course content. Each test consisted of items encountered in the course and an equal number of foils. Experiment 1 involved an initial test of the methodology and addressed test reliability. Experiments 2 and 3 examined performance before and after completion of courses in introductory psychology, the psychology of learning, and the human odyssey. We found strong relations between posttest performance and other measures of academic performance, including essay and multiple-choice tests and final grades. Yes–no tests are fast and reliable tests of memory for course content, and our results demonstrate their potential usefulness for classroom assessment.
Moving toward the Scholarship of Teaching and Learning: The Classroom Can Be a Lab, Too!
Authors: Smith Randolph A.
Published: November 2008

Division 2 of the American Psychological Association was practicing the scholarship of teaching long before Boyer (1990) coined the term, but Boyer brought the idea to academe's consciousness. Over time, however, the scholarship of teaching and “scholarly teaching” have become confused. Based on Richlin's (2001) work, I attempt to resolve this confusion by equating the scholarship of teaching with scholarly work by faculty. In addition, I point out the parallels between assessment and the scholarship of teaching and learning (SoTL) and provide tips for faculty who want to engage in SoTL research but see roadblocks in their way.
2-[18f]-2-deoxy-d-glucose (fdg) uptake in human tumor cells is related to the expression of glut-1 and hexokinase ii
Authors: Ong L.-C. , Jin Y. , Song I.-C. , Yu S. , Zhang K.
Published: November 2008

Background: The uptake of 2-[18F]-2-deoxy-D-glucose (18F-FDG) is widely used as a marker of increased glucose metabolism to monitor progression of cancers with positron emission tomography (PET). Many tumors have been shown to overexpress facilitated glucose transporters, especially GLUT-1 and a glycolytic enzyme, hexokinase II.

Purpose: To define whether a quantitative relationship exists between the expression levels of GLUT-1 and hexokinase II, and 18F-FDG uptake in human cancer xenografts.

Material and Methods: We determined the expression levels of both GLUT-1 and hexokinase II in normal cells and in five different human cancer cell lines (AGS, A431, A549, Colo 320 HSR, and HepG2) using Western blot analysis. In vitro assays of 18F-FDG uptake in cultures were performed, and subsequently representative cell lines were inoculated onto the flanks of severe combined immunodeficient (SCID) mice. To establish an orthotopic model of human hepatocellular carcinoma (HCC), cells were injected into the intraportal vein of SCID mice. 18F-FDG uptake in vivo was assessed by subjecting mice to PET imaging.

Results: All cell lines were shown to express higher amounts of GLUT-1 and hexokinase II compared with fibroblast controls. Our results from in vitro 18F-FDG uptake assays also correlated with the Western blot results. All xenografts gave highly positive results at microPET imaging, and a strong correlation ( R2=0.88, P<0.001) was found between the maximum standardized uptake values (SUVmax) and the expression of GLUT-1 proteins.

Conclusion: Our data indicate that the expression levels of GLUT-1 and hexokinase II as well as in vitro assays of FDG uptake serve as good screening tests to evaluate the feasibility of cell lines to be further developed into xenograft cancer models for small-animal PET imaging.
Spatial Reasoning With External Visualizations: What Matters Is What You See, Not Whether You Interact
Authors: Keehner Madeleine , Hegarty Mary , Cohen Cheryl , Khooshabeh Peter , Montello Daniel R.
Published: November 2008

Three experiments examined the effects of interactive visualizations and spatial abilities on a task requiring participants to infer and draw cross sections of a three‐dimensional (3D) object. The experiments manipulated whether participants could interactively control a virtual 3D visualization of the object while performing the task, and compared participants who were allowed interactive control of the visualization to those who were not allowed control. In Experiment 1, interactivity produced better performance than passive viewing, but the advantage of interactivity disappeared in Experiment 2 when visual input for the two conditions in a yoked design was equalized. In Experiments 2 and 3, differences in how interactive participants manipulated the visualization were large and related to performance. In Experiment 3, non‐interactive participants who watched optimal movements of the display performed as well as interactive participants who manipulated the visualization effectively and better than interactive participants who manipulated the visualization ineffectively. Spatial ability made an independent contribution to performance on the spatial reasoning task, but did not predict patterns of interactive behavior. These experiments indicate that providing participants with active control of a computer visualization does not necessarily enhance task performance, whereas seeing the most task‐relevant information does, and this is true regardless of whether the task‐relevant information is obtained actively or passively.
The Pervasiveness of 1/f Scaling in Speech Reflects the Metastable Basis of Cognition
Authors: Kello Christopher T. , Anderson Gregory G. , Holden John G. , Van Orden Guy C.
Published: November 2008

Human neural and behavioral activities have been reported to exhibit fractal dynamics known as 1/f noise, which is more aptly named 1/f scaling. Some argue that 1/f scaling is a general and pervasive property of the dynamical substrate from which cognitive functions are formed. Others argue that it is an idiosyncratic property of domain‐specific processes. An experiment was conducted to investigate whether 1/f scaling pervades the intrinsic fluctuations of a spoken word. Ten participants each repeated the word bucket over 1,000 times, and fluctuations in acoustic measurements across repetitions generally followed the 1/f scaling relation, including numerous parallel yet distinct series of 1/f fluctuations. On the basis of work showing that 1/f scaling is a universal earmark of metastability, it is proposed that the observed pervasiveness of 1/f fluctuations in speech reflects the fact that cognitive functions are formed as metastable patterns of activity in brain, body, and environment.
Body Parts and Early‐Learned Verbs
Authors: Maouene Josita , Hidaka Shohei , Smith Linda B.
Published: November 2008

This article reports the structure of associations among 101 common verbs and body parts. The verbs are those typically learned by children learning English prior to 3 years of age. In a free association task, 50 adults were asked to provide the single body part that came to mind when they thought of each verb. Analyses reveal highly systematic and structured patterns of associations that are also related to the normative age of acquisition of the verbs showing a progression from verbs associated with actions by the mouth, to verbs strongly associated with actions by hand and arm, to verbs not so strongly associated with any one body part. The results have implications for proposals about embodied verb meaning and also for processes of early verb learning.
Zipf's Law and Avoidance of Excessive Synonymy
Authors: Manin Dmitrii Y.
Published: November 2008

Zipf's law states that if words of language are ranked in the order of decreasing frequency in texts, the frequency of a word is inversely proportional to its rank. It is very reliably observed in the data, but to date it escaped satisfactory theoretical explanation. This article suggests that Zipf's law may result from a hierarchical organization of word meanings over the semantic space, which in turn is generated by the evolution of word semantics dominated by expansion of meanings and competition of synonyms. A study of the frequency of partial synonyms in Russian provides experimental evidence for the hypothesis that word frequency is determined by semantics.
Computer Simulations of Developmental Change: The Contributions of Working Memory Capacity and Long‐Term Knowledge
Authors: Jones Gary , Gobet Fernand , Pine Julian M.
Published: November 2008

Increasing working memory (WM) capacity is often cited as a major influence on children's development and yet WM capacity is difficult to examine independently of long‐term knowledge. A computational model of children's nonword repetition (NWR) performance is presented that independently manipulates long‐term knowledge and WM capacity to determine the relative contributions of each in explaining the developmental data. The simulations show that (a) both mechanisms independently cause the same overall developmental changes in NWR performance, (b) increase in long‐term knowledge provides the better fit to the child data, and (c) varying both long‐term knowledge and WM capacity adds no significant gains over varying long‐term knowledge alone. Given that increases in long‐term knowledge must occur during development, the results indicate that increases in WM capacity may not be required to explain developmental differences. An increase in WM capacity should only be cited as a mechanism of developmental change when there are clear empirical reasons for doing so.
Interpreting Pitch Accents in Online Comprehension: H* vs. L+H*
Authors: Watson Duane G. , Tanenhaus Michael K. , Gunlogson Christine A.
Published: November 2008

Although the presence or absence of a pitch accent clearly can play an important role in signaling the discourse and information structure of an utterance, whether the form of an accent determines the type of information it conveys is more controversial. We used an eye‐tracking paradigm to investigate whether H*, which has been argued to signal new information, evokes different eye fixations than L+H*, which has been argued to signal the presence of contrast. Our results demonstrate that although listeners interpret these accents differently, their interpretive domains overlap. L+H* creates a strong bias toward contrast referents whereas H* is compatible with both new and contrast referents.
Space Between Languages
Authors: Feist Michele I.
Published: November 2008

What aspects of spatial relations influence speakers’ choice of locative? This article presents a study of static spatial descriptions from 24 languages. The study reveals two kinds of spatial terms evident cross‐linguistically: specific spatial terms and general spatial terms (GSTs). Whereas specific spatial terms—including English prepositions—occur in a limited range of situations, with concomitant specificity in their meaning, GSTs occur in all spatial descriptions (in languages that employ them). Because of the extreme differences in range of application, the two are considered separately. A multidimensional scaling analysis is used with specific spatial terms to extract statistically valid similarities across the languages sampled. For GSTs, which have not been previously analyzed in the literature, a semantic analysis is proposed and experimentally validated. The results suggest the importance of geometry, function, and qualitative physics to the meanings of both kinds of spatial terms, although the details differ.
Optimal Predictions in Everyday Cognition: The Wisdom of Individuals or Crowds?
Authors: Mozer Michael C. , Pashler Harold , Homaei Hadjar
Published: November 2008

asked individuals to make predictions about the duration or extent of everyday events (e.g., cake baking times), and reported that predictions were optimal, employing Bayesian inference based on veridical prior distributions. Although the predictions conformed strikingly to statistics of the world, they reflect averages over many individuals. On the conjecture that the accuracy of the group response is chiefly a consequence of aggregating across individuals, we constructed simple, heuristic approximations to the Bayesian model premised on the hypothesis that individuals have access merely to a sample of k instances drawn from the relevant distribution. The accuracy of the group response reported by Griffiths and Tenenbaum could be accounted for by supposing that individuals each utilize only two instances. Moreover, the variability of the group data is more consistent with this small‐sample hypothesis than with the hypothesis that people utilize veridical or nearly veridical representations of the underlying prior distributions. Our analyses lead to a qualitatively different view of how individuals reason from past experience than the view espoused by Griffiths and Tenenbaum.
Gentamicin complexes of cobalt(II), nickel(II), cadmium(II) and tin(II)
Authors: Mishra Parashuram , Sharma Rakesh K.
Published: November 2008

Gentamicin is an aminoglycoside antibiotic with known adverse side effects to the kidney and the inner ear. It is proposed that these effects result from complex formation of gentamicin with Co (1), Ni (2), Cd (3) and Sn (4). Metal coordination to gentamicin was studied by various spectroscopic techniques. The crystal system, lattice parameters, unit cell, particle size and volume were determined by XRPD. The crystallographic data of complex (2) are: Monoclinic, space groupP4/m, a = 16.67920Å, b = 12.71476Å, c = 5.2673Å, V = 1112.00Å3, α = 90, β = 95.21, γ = 90° and for complex (4): crystal system, Triclinic, space group, P1, a = 8.290549, b = 9.619387, c = 16.12853, α = 63.75208, β = 53.3017, γ = 62.28692, V = 888.68. The molecular structures of the complexes were optimized by MM2 calculations which indicated a square planar arrangement of gentamicin around the metal ions.
Theoretical study of classical isomers tropylium, azatropylium, phosphatropylium, and arsatropylium cations: structure, properties and aromaticity
Authors: Ghiasi Reza
Published: November 2008

The electronic structure and properties of the classical isomers tropylium, azatropylium, phosphatropylium and arsatropylium have been investigated using hybrid density functional B3LYP theory. Basic measures of aromatic character were derived from structure, molecular orbital and magnetic properties. Energetic criteria suggest that tropylium cation and similar hetero-systems favour conspicuous stabilisation. On the basis of the magnetic criteria, the N1, P0, As0 isomers are among the most aromatic of the family. The results showed that aromaticity decreases in C6XH6+ with increasing size of the group 15 element (X = N, P, As).
A Contract for Success? Attitudes About Professional Development Among News Directors and Producers
Authors: Cleary Johanna
Published: November 2008

Professional development training is often cited by journalists as a way to improve skills and increase job satisfaction and employee retention, yet it's significantly underused in the field of broadcast journalism. This study contrasts the attitudes of news directors and producers - classic “knowledge workers” - toward professional development in commercial broadcast newsrooms. Results indicate there are significant differences in how news directors and local broadcast producers perceive the availability and value of professional development, how they view its importance to promotion, and whether they consider it a factor in job satisfaction. The results build on the theory of psychological contracts to examine how the availability of training can affect organizational commitment for highly-valued local broadcast producers.
Preparing for Disaster: An Examination of Public Health Emergency Information on Local TV Web Sites
Authors: Tanner Andrea , Friedman Daniela B. , Barr Daphney , Koskan Alexis
Published: November 2008

This study provides a nationwide examination of public health emergency information on local television Web sites, analyzing 293 news stories that focused on all aspects of a potential emergency, including preparedness, response, and recovery. Data revealed that public health emergency information was present on nearly all (96%) of the sites examined. These stories most frequently contained general disaster information, or information about weather-related disasters and health pandemics.

Few stories linked consumers to additional information on other Web pages (24%) or included a video component (27%). There were significant differences between large and small media markets regarding specific public health emergency content.
Respirator-Fit Testing: Does It Ensure the Protection of Healthcare Workers Against Respirable Particles Carrying Pathogens?
Authors: Lee M. C. , Takaya S. , Long R. , Joffe A. M.
Published: November 2008

Objective.

Respiratory protection programs, including fit testing of respirators, have been inconsistently implemented; evidence of their long-term efficacy is lacking. We undertook a study to determine the short- and long-term efficacy of training for fit testing of N95 respirators in both untrained and trained healthcare workers (HCWs).

Design.

Prospective observational cohort study.

Methods.

A group of at-risk, consenting HCWs not previously fit-tested for a respirator were provided with a standard fit-test protocol. Participants were evaluated after each of 3 phases, and 3 and 14 months afterward. A second group of previously fit-tested nurses was studied to assess the impact of regular respirator use on performance.

Results.

Of 43 untrained fit-tested HCWs followed for 14 months, 19 (44.2%) passed the initial fit test without having any specific instruction on respirator donning technique. After the initial test, subsequent instruction led to a pass for another 13 (30.2%) of the 43 HCWs, using their original respirators. The remainder required trying other types of respirators to acheive a proper fit. At 3 and 14 months' follow-up, failure rates of 53.5% (23 of 43 HCWs) and 34.9% (15 of 43 HCWs), respectively, were observed. Pass rates of 87.5%-100.0% were observed among regular users.

Conclusions.

Without any instruction, nearly 50% of the HCWs achieved an adequate facial seal with the most commonly used N95 respirator. Formal fit testing does not predict future adequacy of fit, unless frequent, routine use is made of the respirator. The utility of fit testing among infrequent users of N95 respirators is questionable.
Cytokines and Myelination in the Central Nervous System
Authors: Schmitz Thomas , Chew Li-Jin
Published: November 2008

Myelin abnormalities that reflect damage to developing and mature brains are often found in neurological diseases with evidence of inflammatory infiltration and microglial activation. Many cytokines are virtually undetectable in the uninflamed central nervous system (CNS), so that their rapid induction and sustained elevation in immune and glial cells contributes to dysregulation of the inflammatory response and neural cell homeostasis. This results in aberrant neural cell development, cytotoxicity, and loss of the primary myelin-producing cells of the CNS, the oligodendrocytes. This article provides an overview of cytokine and chemokine activity in the CNS with relevance to clinical conditions of neonatal and adult demyelinating disease, brain trauma, and mental disorders with observed white matter defects. Experimental models that mimic human disease have been developed in order to study pathogenic and therapeutic mechanisms, but have shown mixed success in clinical application. However, genetically altered animals, and models of CNS inflammation and demyelination, have offered great insight into the complexities of neuroimmune interactions that impact oligodendrocyte function. The intracellular signaling pathways of selected cytokines have also been highlighted to illustrate current knowledge of receptor-mediated events. By learning to interpret the actions of cytokines and by improving methods to target appropriate predictors of disease risk selectively, a more comprehensive understanding of altered immunoregulation will aid in the development of advanced treatment options for patients with inflammatory white matter disorders.
Tpr directly binds to Mad1 and Mad2 and is important for the Mad1–Mad2-mediated mitotic spindle checkpoint
Authors: Lee Sang Hyun , Sterling Harry , Burlingame Alma , McCormick Frank
Published: November 2008

The mitotic arrest-deficient protein Mad1 forms a complex with Mad2, which is required for imposing mitotic arrest on cells in which the spindle assembly is perturbed. By mass spectrometry of affinity-purified Mad2-associated factors, we identified the translocated promoter region (Tpr), a component of the nuclear pore complex (NPC), as a novel Mad2-interacting protein. Tpr directly binds to Mad1 and Mad2. Depletion of Tpr in HeLa cells disrupts the NPC localization of Mad1 and Mad2 during interphase and decreases the levels of Mad1-bound Mad2. Furthermore, depletion of Tpr decreases the levels of Mad1 at kinetochores during prometaphase, correlating with the inability of Mad1 to activate Mad2, which is required for inhibiting APCCdc20. These findings reveal an important role for Tpr in which Mad1–Mad2 proteins are regulated during the cell cycle and mitotic spindle checkpoint signaling.
Sfrp5 coordinates foregut specification and morphogenesis by antagonizing both canonical and noncanonical Wnt11 signaling
Authors: Li Yan , Rankin Scott A. , Sinner Débora , Kenny Alan P. , Krieg Paul A. , Zorn Aaron M.
Published: November 2008

Cell identity and tissue morphogenesis are tightly orchestrated during organogenesis, but the mechanisms regulating this are poorly understood. We show that interactions between Wnt11 and the secreted Wnt antagonist secreted frizzled-related protein 5 (Sfrp5) coordinate cell fate and morphogenesis during Xenopus foregut development. sfrp5 is expressed in the surface cells of the foregut epithelium, whereas wnt11 is expressed in the underlying deep endoderm. Depletion of Sfrp5 results in reduced foregut gene expression and hypoplastic liver and ventral pancreatic buds. In addition, the ventral foregut cells lose adhesion and fail to form a polarized epithelium. We show that the cell fate and epithelial defects are due to inappropriate Wnt/β-catenin and Wnt/PCP signaling, respectively, both mediated by Wnt11. We provide evidence that Sfrp5 locally inhibits Wnt11 to maintain early foregut identity and to allow an epithelium to form over a mass of tissue undergoing Wnt-mediated cell movements. This novel mechanism coordinating canonical and noncanonical Wnt signaling may have broad implications for organogenesis and cancer.
Coordinated but physically separable interaction with H3K27-demethylase and H3K4-methyltransferase activities are required for T-box protein-mediated activation of developmental gene expression
Authors: Miller Sara A. , Huang Albert C. , Miazgowicz Michael M. , Brassil Margaret M. , Weinmann Amy S.
Published: November 2008

During cellular differentiation, both permissive and repressive epigenetic modifications must be negotiated to create cell-type-specific gene expression patterns. The T-box transcription factor family is important in numerous developmental systems ranging from embryogenesis to the differentiation of adult tissues. By analyzing point mutations in conserved sequences in the T-box DNA-binding domain, we found that two overlapping, but physically separable regions are required for the physical and functional interaction with H3K27-demethylase and H3K4-methyltransferase activities. Importantly, the ability to associate with these histone-modifying complexes is a conserved function for the T-box family. These novel mechanisms for T-box-mediated epigenetic regulation are essential, because point mutations that disrupt these interactions are found in a diverse array of human developmental genetic diseases.
A genome-wide shRNA screen identifies GAS1 as a novel melanoma metastasis suppressor gene
Authors: Gobeil Stephane , Zhu Xiaochun , Doillon Charles J. , Green Michael R.
Published: November 2008

Metastasis suppressor genes inhibit one or more steps required for metastasis without affecting primary tumor formation. Due to the complexity of the metastatic process, the development of experimental approaches for identifying genes involved in metastasis prevention has been challenging. Here we describe a genome-wide RNAi screening strategy to identify candidate metastasis suppressor genes. Following expression in weakly metastatic B16-F0 mouse melanoma cells, shRNAs were selected based upon enhanced satellite colony formation in a three-dimensional cell culture system and confirmed in a mouse experimental metastasis assay. Using this approach we discovered 22 genes whose knockdown increased metastasis without affecting primary tumor growth. We focused on one of these genes, Gas1 (Growth arrest-specific 1), because we found that it was substantially down-regulated in highly metastatic B16-F10 melanoma cells, which contributed to the high metastatic potential of this mouse cell line. We further demonstrated that Gas1 has all the expected properties of a melanoma tumor suppressor including: suppression of metastasis in a spontaneous metastasis assay, promotion of apoptosis following dissemination of cells to secondary sites, and frequent down-regulation in human melanoma metastasis-derived cell lines and metastatic tumor samples. Thus, we developed a genome-wide shRNA screening strategy that enables the discovery of new metastasis suppressor genes.
Site-specific cross-linking of TBP in vivo and in vitro reveals a direct functional interaction with the SAGA subunit Spt3
Authors: Mohibullah Neeman , Hahn Steven
Published: November 2008

The TATA-binding protein (TBP) is critical for transcription by all three nuclear RNA polymerases. In order to identify factors that interact with TBP, the nonnatural photoreactive amino acid ρ-benzoyl-phenylalanine (BPA) was substituted onto the surface of Saccharomyces cerevisiae TBP in vivo. Cross-linking of these TBP derivatives in isolated transcription preinitiation complexes or in living cells reveals physical interactions of TBP with transcriptional coregulator subunits and with the general transcription factor TFIIA. Importantly, the results show a direct interaction between TBP and the SAGA coactivator subunits Spt3 and Spt8. Mutations on the Spt3-interacting surface of TBP significantly reduce the interaction of TBP with SAGA, show a corresponding decrease in transcription activation, and fail to recruit TBP to a SAGA-dependent promoter, demonstrating that the direct interaction of these factors is important for activated transcription. These results prove a key prediction of the model for stimulation of transcription at SAGA-dependent genes via Spt3. Our cross-linking data also significantly extend the known surfaces of TBP that directly interact with the transcriptional regulator Mot1 and the general transcription factor TFIIA.
Intraspecific evolution of the intercellular signaling network underlying a robust developmental system
Authors: Milloz Josselin , Duveau Fabien , Nuez Isabelle , Félix Marie-Anne
Published: November 2008

Many biological systems produce an invariant output when faced with stochastic or environmental variation. This robustness of system output to variation affecting the underlying process may allow for “cryptic” genetic evolution within the system without change in output. We studied variation of cell fate patterning of Caenorhabditis elegans vulva precursors, a developmental system that relies on a simple intercellular signaling network and yields an invariant output of cell fates and lineages among C. elegans wild isolates. We first investigated the system’s genetic variation in C. elegans by means of genetic tools and cell ablation to break down its buffering mechanisms. We uncovered distinct architectures of quantitative variation along the Ras signaling cascade, including compensatory variation, and differences in cell sensitivity to induction along the anteroposterior axis. In the unperturbed system, we further found variation between isolates in spatio-temporal dynamics of Ras pathway activity, which can explain the phenotypic differences revealed upon perturbation. Finally, the variation mostly affects the signaling pathways in a tissue-specific manner. We thus demonstrate and characterize microevolution of a developmental signaling network. In addition, our results suggest that the vulva genetic screens would have yielded a different mutation spectrum, especially for Wnt pathway mutations, had they been performed in another C. elegans genetic background.
Construction of Nucleic Acid Programmable Protein Arrays (NAPPA) 7: Detecting DNA on NAPPA Slides: Figure 1.
Authors: Link Andrew J. , LaBaer Joshua
Published: November 2008

INTRODUCTION

Functional proteomics enables protein activities to be studied in vitro using high-throughput (HT) methods. Protein microarrays are the method of choice because they display many proteins simultaneously and require only small reaction volumes to assess function. Protein microarrays are typically used to (1) measure the abundance of many different analytes in a sample or (2) study the functions or properties of many proteins spotted on the array. Target protein microarrays are usually generated by expressing, purifying, and spotting the proteins onto a solid surface at very close spatial density. An alternative approach is to translate the proteins in situ on the array surface. This method uses cell-free extracts that transcribe and translate DNA into proteins which are then captured in situ, thus converting cDNA copies of genes into the desired target proteins. Instead of printing proteins at each feature of the array, the cDNA molecules for the corresponding genes that produce desired proteins are affixed to the array. Chemical treatment of glass slides and DNA isolation can be performed in advance and stored. The plasmid DNA can then be printed to make NAPPA slides, which can be stored dry for use. For experiments, NAPPA slides are expressed followed by detection of proteins and DNA using antibodies and stains. This protocol describes detection of DNA on arrayed slides to assess the amount of DNA captured.
Sex Chromatin Staining in Amnion Cells
Authors: Capel Blanche , Batchvarov Jordan
Published: November 2008

INTRODUCTION

The procedure described here provides a quick and reliable method for determining the sex of mouse embryos that are <12.5 days post-coitum (dpc). Cells from amniotic membranes are stained with toluidine blue. The presence of a heavily stained condensed chromatin body (i.e., a Barr body) indicates the XX samples. With experience, we find a >95% concordance with genotyping data based on PCR for Y-chromosome sequences in extracted tail DNA. This protocol has the advantage of speed and efficiency: When assembling cultures with live tissue, samples can be sexed in 30 min.
Grafting Tomato Plants
Authors: Kimura Seisuke , Sinha Neelima
Published: November 2008

INTRODUCTION

Grafting is agronomically important because one can combine desirable aboveground characteristics (such as fruit size) and underground characteristics (such as resistance to soil-borne diseases). This protocol describes the simplest way of grafting tomato plants using “top wedge grafting” or “cleft grafting.” Potatoes, eggplants, and tobacco plants are closely related to tomatoes, and they can be grafted onto each other as well. Although the grafting of vegetable crops is still rare, this technique has been useful in reducing infections caused by pathogens, increasing resistance to drought, and enhancing nutrient uptake.
Tomato Transformation: Figure 1.
Authors: Kimura Seisuke , Sinha Neelima
Published: November 2008

INTRODUCTION

Transformation is an essential technique to analyze the function of genes. Tomato can be stably transformed using Agrobacterium tumefaciens-mediated transfer of T-DNA. This protocol describes an Agrobacterium-mediated transformation method for tomato.
In Vitro Fertilization of Astyanax mexicanus
Authors: Borowsky Richard
Published: November 2008

INTRODUCTION

This protocol describes an alternative method for breeding Astyanax mexicanus, using in vitro fertilization. Sperm collected from the male and eggs collected from the female are placed in a Petri dish, and sperm are activated by the addition of fresh system water. The eggs are observed under low magnification for signs of fertilization, usually marked by the onset of cleavage.
Met gene copy number predicts the prognosis for completely resected non‐small cell lung cancer
Authors: Okuda Katsuhiro , Sasaki Hidefumi , Yukiue Haruhiro , Yano Motoki , Fujii Yoshitaka
Published: November 2008

The Met oncogene encodes the tyrosine kinase receptor for hepatocyte growth factor (HGF). Uncontrolled activation of Met is oncogenic and has been implicated in the growth, invasion and metastasis in a variety of tumors. Several distinct mechanisms including amplification, translocation or mutation of Met may underlie uncontrolled Met activation. In several solid tumors, amplification and mutation of Met were reported to be associated with tumorigenesis, invasion and metastasis. The present study evaluated the amplification and mutation of Met in a large number of non‐small cell lung cancer (NSCLC). Among 213 NSCLC patients, increased Met copy number was identified in 12 patients (5.6%) and associated with a worse prognosis (P = 0.0414). The mutation of Met in 534 NSCLC patients was also evaluated. In these patients there were no previously reported mutations within the juxtamembrane (JM) domain (R988C, T1010I, S1058P and G1085X). However, a somatic exon 14 deleting splice variant in 3 (1.7%) of 178 NSCLC samples was identified for which sequencing was performed. Met amplification and mutation were rare in Japanese NSCLC. However, the results support a critical role of Met gene dose in NSCLC, suggesting that Met may be a specific molecular therapeutic target in selected NSCLC patients with increased Met copy number. (Cancer Sci 2008; 99: 2280–2285)
Binding of monosodium urate crystals with idiotype protein efficiently promote dendritic cells to induce cytotoxic T cells
Authors: Sakamaki Ippei , Inai Kunihiro , Tsutani Yoko , Ueda Takanori , Tsutani Hiroshi
Published: November 2008

Monosodium urate (MSU) crystals have been reported to evoke specific cell immunity and to work as an adjuvant in a mouse model. The crystals also have another unique characteristic to bind with positively charged proteins, which could help to deliver some antigens into human dendritic cells (DC). We focused on the application of MSU crystals as not only an adjuvant but also as a carrier of positively charged antigenic protein to induce human cytotoxic T cells (CTL) efficiently in vitro. We selected human leukocyte antigen (HLA)‐A2 expressing the multiple myeloma IM‐9 cell line and its product idiotype (Id) protein as one of the best pairs of target cells and positively charged tumor‐specific antigen, respectively. Following the sensitization of DC derived from HLA‐A2‐positive volunteers pulsed with tumor‐specific monoclonal immunoglobulin G‐Fab fragments (IM‐9 Fab) attached to MSU crystals, the DC‐stimulated CD8+ T cells killed significantly more target cells (40.1 ± 1.7%) than those stimulated by DC pulsed with MSU crystals alone (6.2 ± 8.6%, P < 0.01) or IM‐9 Fab alone (4.7 ± 8.1%, P < 0.01). These cytotoxic effects of the DC‐stimulated CD8+ cells were reduced when MSU crystals were precoated with fetal bovine serum. In addition, we confirmed that MSU crystals facilitated human DC to express the maturation marker, CD83 and deliver (Fab′)2, attaching to the crystals by flow cytometer analysis. MSU crystals have distinct advantages of a protein carrier binding with positively charged proteins and delivering antigenic protein into DC, as well as an adjuvant promoting DC maturation and inducing CTL. (Cancer Sci 2008; 99: 2268–2273)