bluuebunny/crossref_metadata_2025 huggingface dataset:
Associations among Individual, Social, and Environmental Barriers and Children's Walking or Cycling to School
Authors: Salmon Jo , Salmon Louisa , Crawford David A. , Hume Clare , Timperio Anna
Published: October 2011

Purpose.

To examine associations among individual, social, and environmental barriers and children's walking or cycling to school.

Design.

Exploratory cross-sectional study.

Setting.

All eight capital cities in Australia.

Subjects.

Parents (N = 720) of school-aged children (4–13 years; 27% response rate; 49% parents of boys).

Measures.

Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) for parental reporting of barriers to their children's walking or cycling to school, based on a computer-assisted telephone interview.

Results.

Forty-one percent of children walked or cycled to school at least once per week. Multivariable analyses found inverse associations with individual (“child prefers to be driven” [OR = 0.4, 95% CI = 0.3–0.6], “no time in the mornings” [OR = 0.5, 95% CI = 0.3–0.8]); social (“worry child will take risks” [OR = 0.6, 95% CI = 0.3–0.9], “no other children to walk with” [OR = 0.7, 95% CI = 0.4–0.99], “no adults to walk with” [OR = 0.6, 95% CI = 0.4–0.9]); and environmental barriers (“too far to walk” [OR = 0.1, 95% CI = 0.0–0.1], “no direct route” [OR = 0.4, 95% CI = 0.2–0.7]) and positive associations with “concern child may be injured in a road accident” (OR = 1.9, 95% CI = 1.1–3.1) and active commuting.

Conclusion.

Working with parents, schools, and local authorities to improve pedestrian skills and environments may help to overcome barriers.
Promoting Stair Climbing: Intervention Effects Generalize to a Subsequent Stair Ascent
Authors: Webb Oliver J. , Eves Frank F.
Published: October 2011

Purpose.

Studies report a significant increase in stair use when message prompts are introduced at the “point of choice” between stairs and escalators. Climbing one set of stairs, however, will not confer meaningful health dividends. Therefore, this study examined whether exposure to point of choice prompts also encouraged individuals to climb the next set of stairs that they encountered.

Design.

Interrupted time-series design.

Settings.

Two separate stair/escalator pairings within a U.K. shopping mall (the “intervention” site and the “generalization” site), separated by a 25-m long atrium.

Subjects.

Ascending pedestrians (intervention site n = 29,713; generalization site n = 47,553).

Interventions.

Two weeks of baseline monitoring were followed by a 13-week intervention in which banners carrying health promotion messages were introduced at the intervention site only.

Measures.

At both sites observers inconspicuously recorded pedestrians' methods of ascent, along with their gender, age, ethnicity, and baggage.

Results.

Banners increased stair climbing at the intervention site by 161%. Results also suggested a simultaneous increase of up to 143% at the generalization site, where no prompt was in place. At both sites stair use remained significantly elevated 5 weeks after the banners were removed.

Conclusions.

It appears that exposure to point of choice prompts can encourage pedestrians to climb stairs when they are encountered in a subsequent setting. Consequently stair-climbing interventions are likely to engage the public in more physical activity than previously realized.
Exercise and Self-Esteem in Menopausal Women: A Randomized Controlled Trial Involving Walking and Yoga
Authors: Elavsky Steriani , McAuley Edward
Published: October 2011

Purpose.

To examine the effects of walking and yoga on multidimensional self-esteem and roles played by self-efficacy, body composition, and physical activity (PA) in changes in esteem.

Design.

Four-month randomized controlled exercise trial with three arms: walking, yoga, and control.

Subjects.

Previously low-active middle-aged women (n = 164; M age = 49.9; SD = 3.6).

Intervention.

Structured and supervised walking program meeting three times per week for 1 hour and supervised yoga program meeting twice per week for 90 minutes.

Measures.

Body composition, fitness assessment, and battery of psychologic measures.

Analysis.

Panel analysis within a structural equation modeling framework using Mplus 3.0.

Results.

The walking and yoga interventions failed to enhance global or physical self-esteem but improved subdomain esteem relative to physical condition and strength (for walking) and body attractiveness (for both walking and yoga). Over time the effects of PA, self-efficacy, and body fat on changes in physical self-esteem and global esteem were mediated by changes in physical condition and body attractiveness subdomain esteem. Women reporting greater levels of self-efficacy and PA with lower body fat also reported greater enhancements in subdomain esteem.

Conclusion.

These results provide support for the hierarchic and multidimensional nature of self-esteem and indicate that middle-aged women may enhance certain aspects of physical self-esteem by participating in PA.
Using radium isotopes to characterize water ages and coastal mixing rates: A sensitivity analysis
Authors: Knee Karen L. , Garcia‐Solsona Ester , Garcia‐Orellana Jordi , Boehm Alexandria B. , Paytan Adina
Published: October 2011

Numerous studies have used naturally occurring Ra isotopes (223Ra, 224Ra, 226Ra, and 228Ra, with half‐lives of 11.4 d, 3.7 d, 1600 y, and 5.8 y, respectively) to quantify water mass ages, coastal ocean mixing rates, and submarine groundwater discharge (SGD). Using Monte Carlo models, this study investigated how uncertainties in Ra isotope activities and the derived activity ratios (AR) arising from analytical uncertainty and natural variability affect the uncertainty associated with Ra‐derived water ages and eddy diffusion coefficients, both of which can be used to calculate SGD. Analytical uncertainties associated with 224Ra, 226Ra, and 228Ra activities were reported in most published studies to be less than 10% of sample activity; those reported for 223Ra ranged from 7% to 40%. Relative uncertainty related to natural variability — estimated from the variability in 223Ra and 224Ra activities of replicate field samples — ranged from 15% to 50% and was similar for 223Ra activity, 224Ra activity, and the 224Ra/223Ra AR. Our analysis revealed that AR‐based water ages shorter than 3–5 d often have relative uncertainties greater than 100%, potentially limiting their utility. Uncertainties in eddy diffusion coefficients estimated based on cross‐shore gradients in short‐lived Ra isotope activity were greater when fewer points were used to determine the linear trend, when the coefficient of determination (R2) was low, and when 224Ra, rather than 223Ra, was used. By exploring the uncertainties associated with Ra‐derived water ages and eddy diffusion coefficients, this study will enable researchers to apply these methods more effectively and to reduce uncertainty.
Storage bottle material and cleaning for determination of total mercury in seawater
Authors: Hammerschmidt Chad R. , Bowman Katlin L. , Tabatchnick Melissa D. , Lamborg Carl H.
Published: October 2011

Accurate determinations of trace levels of mercury (Hg) in water require scrupulously clean sampling equipment and storage bottles. To avoid Hg contamination during storage, it has been presumed that water samples must be stored in either glass or Teflon bottles cleaned with a rigorous method, such as submersion in hot acid. These cleaning procedures are hazardous, and use of Teflon bottles can be cost prohibitive for major oceanographic programs. We investigated the suitability of alternative cleaning procedures and bottle materials for storage of seawater containing sub‐picomolar levels of Hg. We found that a simple technique with detergent, dilute acid, and bromine monochloride removes Hg from all bottle materials tested, which included FEP Teflon, glass, polycarbonate (PC), low‐density polyethylene (LDPE), and fluorinated polyethylene (FLPE). The technique is effective for bottles that are either new or used previously for trace‐level oceanographic samples (total Hg < 10 pM). Stability of seawater Hg levels differed dramatically among storage bottle materials during a 74‐ week test. Hg in seawater stored in LDPE, FLPE, and FEP bottles increased within 15 weeks of storage at room temperature. In contrast, Hg levels in seawater stored in PC bottles were increased modestly only after 74 weeks of storage and those in glass bottles were unchanged throughout the test. We recommend future use of this new cleaning method and encourage greater use of glass and PC bottles for storage of waters containing low levels of Hg.
Effects of Moisture on the Switching Characteristics of Oxide‐Based, Gapless‐Type Atomic Switches
Authors: Tsuruoka Tohru , Terabe Kazuya , Hasegawa Tsuyoshi , Valov Ilia , Waser Rainer , Aono Masakazu
Published: October 2011

Resistive switching memories based on the formation and dissolution of a metal filament in a simple metal/oxide/metal structure are attractive because of their potential high scalability, low‐power consumption, and ease of operation. From the standpoint of the operation mechanism, these types of memory devices are referred to as gapless‐type atomic switches or electrochemical metallization cells. It is well known that oxide materials can absorb moisture from the ambient air, which causes shifts in the characteristics of metal‐oxide‐semiconductor devices. However, the role of ambient moisture on the operation of oxide‐based atomic switches has not yet been clarified. In this work, current–voltage measurements were performed as a function of ambient water vapor pressure and temperature to reveal the effect of moisture on the switching behavior of Cu/oxide/Pt atomic switches using different oxide materials. The main findings are: i) the ionization of Cu at the anode interface is likely to be attributed to chemical oxidation via residual water in the oxide layer, ii) Cu ions migrate along grain boundaries in the oxide layer, where a hydrogen‐bond network might be formed by moisture absorption, and iii) the stability of residual water has an impact on the ionization and migration processes and plays a major role in determining the operation voltages. These findings will be important in the microscopic understanding of the switching behavior of oxide‐based atomic switches and electrochemical metallization cells.
Sirenomelia: An epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research, and literature review
Authors: Orioli Iêda M. , Amar Emmanuelle , Arteaga‐Vazquez Jazmin , Bakker Marian K. , Bianca Sebastiano , Botto Lorenzo D. , Clementi Maurizio , Correa Adolfo , Csaky‐Szunyogh Melinda , Leoncini Emanuele , Li Zhu , López‐Camelo Jorge S. , Lowry R. Brian , Marengo Lisa , Martínez‐Frías María‐Luisa , Mastroiacovo Pierpaolo , Morgan Margery , Pierini Anna , Ritvanen Annukka , Scarano Gioacchino , Szabova Elena , Castilla Eduardo E.
Published: October 2011

Sirenomelia is a very rare limb anomaly in which the normally paired lower limbs are replaced by a single midline limb. This study describes the prevalence, associated malformations, and maternal characteristics among cases with sirenomelia. Data originated from 19 birth defect surveillance system members of the International Clearinghouse for Birth Defects Surveillance and Research, and were reported according to a single pre‐established protocol. Cases were clinically evaluated locally and reviewed centrally. A total of 249 cases with sirenomelia were identified among 25,290,172 births, for a prevalence of 0.98 per 100,000, with higher prevalence in the Mexican registry. An increase of sirenomelia prevalence with maternal age less than 20 years was statistically significant. The proportion of twinning was 9%, higher than the 1% expected. Sex was ambiguous in 47% of cases, and no different from expectation in the rest. The proportion of cases born alive, premature, and weighting less than 2,500 g were 47%, 71.2%, and 88.2%, respectively. Half of the cases with sirenomelia also presented with genital, large bowel, and urinary defects. About 10–15% of the cases had lower spinal column defects, single or anomalous umbilical artery, upper limb, cardiac, and central nervous system defects. There was a greater than expected association of sirenomelia with other very rare defects such as bladder exstrophy, cyclopia/holoprosencephaly, and acardia‐acephalus. The application of the new biological network analysis approach, including molecular results, to these associated very rare diseases is suggested for future studies. © 2011 Wiley Periodicals, Inc.
Synthesis and Biological Evaluation of Antitumor‐Active Arglabin Derivatives
Authors: Csuk René , Heinold Anke , Siewert Bianka , Schwarz Stefan , Barthel Alexander , Kluge Ralph , Ströhl Dieter
Published: October 2011

Arglabin derivatives varied at the endo‐ or exo‐cyclic double bond were synthesized and studied in a colorimetric sulforhodamine B assay for their cytotoxicity. Variations on the endocyclic double bond led to compounds of reduced cytotoxicity whereas derivatives from the reaction of the α‐methylene‐γ‐butyrolactone moiety led to compounds of similar or only slightly reduced cytotoxicity but different, cell line‐dependent selectivity. In addition, arglabin is an excellent starting material for the synthesis of the guaianolide arborescin.
Green chiral HPLC enantiomeric separations using high temperature liquid chromatography and subcritical water on chiralcel OD and chiralpak AD
Authors: Droux Serge , Félix Guy
Published: October 2011

We report here the application of subcritical water in chiral separations on two popular polysaccharide chiral stationary phases (CSPs): Chiralpak AD and Chiralcel OD. The behavior of these two CSPs was studied under reversed phase conditions at room temperature to discover the maximum percentage of water in the mobile phase, which provided the separation of enantiomers of flavanone and benzoin, respectively, in a reasonable time (i.e., less than 1 h). Then, the stability of Chiralpak AD and Chiralcel OD versus temperature was investigated and discussed. Chiralcel OD separation of flavanone racemate was obtained at 120°C with water and 2‐propanol (80/20) as the mobile phase, while benzoin racemate was separated in pure water at 160°C. Separations of several racemates were also presented, and advantages and limitations of the technique were discussed. Chirality, 2011. © 2011 Wiley Periodicals, Inc.
Particle Shapes in the Drinking Water Filtration Process
Authors: Zielina Michał
Published: October 2011

Depth filtration is still one of the most important water treatment processes. It remains difficult to model mathematically because of the complexity of the process and the impact of numerous suspension parameters. The shape of the grains and suspension particles or flocs are among these parameters. The results of theoretical calculations suggest their visible impact on filtration. The shape of the media grain is relatively easy to measure. The shapes of the flocs or suspension particles, which are commonly not perfectly spherical, are much more difficult to predict. However, a few apparatuses developed lasting recent years make this possible. The FPIA 3000, manufactured by Malvern Instruments, uses flow particle image analysis method to measure 26 shape parameters of the suspension particles. Experimental measurement of suspension particle shape after flocculation and after depth filtration has allowed us to answer the question regarding the possible application of this measuring technique in water filtration technology. The experiments have also provided us with detailed information about the shape of flocs and suspension particles in filtered water. High number of particles characterized by circularity lower than 0.8 was detected in flocculated water inflowing to the filter. The particles remained in the outflow was characterized by visibly higher circularity than the particles inflowing to the filter. The results revealed much better removal of the particles characterized by lower circularity during filtration, whereas relation between convexity of the particles and their removal efficiency was not so evident.
Nitrogen‐Doped Carbon Nanotubes: Growth, Mechanism and Structure
Authors: O'Byrne Justin P. , Li Zhonglai , Jones Sarah L. T. , Fleming Peter G. , Larsson J. Andreas , Morris Michael A. , Holmes Justin D.
Published: October 2011

Nitrogen‐doped bamboo‐structured carbon nanotubes have been successfully grown using a series of cobalt/molybdenum catalysts. The morphology and structure of the nanotubes were analysed by transmission electron microscopy and Raman spectroscopy. The level of nitrogen doping, as determined by X‐ray photoelectron spectroscopy, was found to range between 0.5 to 2.5 at. %. The growth of bamboo‐structured nanotubes in the presence of nitrogen, in preference to single‐walled and multi‐walled nanotubes, was due to the greater binding energy of nitrogen for cobalt in the catalyst compared to the binding strength of carbon to cobalt, as determined by density functional theory.
Cyclopentadienyl–NHC Iron Complexes for Solvent‐Free Catalytic Hydrosilylation of Aldehydes and Ketones
Authors: Bézier David , Jiang Fan , Roisnel Thierry , Sortais Jean‐Baptiste , Darcel Christophe
Published: October 2011

Seven cyclopentadienyl–NHC piano‐stool iron complexes were prepared and studied in the catalytic hydrosilylation of aldehydes and ketones under visible light irradiation. A significant acceleration of the rate was observed when the reactions were carried out under solvent‐free conditions. Single‐crystal X‐ray structural analyses were performed for complexes 5 and 7.
Synthetic Strategies Directed Towards 5a‐Carbahexopyranoses and Derivatives Based on 6‐endo‐trig Radical Cyclizations
Authors: Gómez Ana M. , Uriel Clara , Company Maria D. , López J. Cristóbal
Published: October 2011

Several synthetic strategies directed towards 5a‐carbahexopyranoses and based on 6‐endo‐trig radical cyclization of unsaturated carbohydrate derivatives have been devised. Three elements for regiocontrol to optimize the 6‐endo/5‐exo ratio have been incorporated, and their efficiencies in directing 6‐endo cyclizations have been evaluated. These elements – namely: i) the incorporation of a substituent at C‐5 (radical numbering), ii) the use of a vinyl (rather than alkyl) radical, and iii) the inclusion of ring strain in the system – have proved useful when used in combination. The simultaneous presence of two of them also results in 6‐endo selectivity. On another topic, the ozonation of the ensuing alkenylstananes to afford diols seems to be based on a tin‐oxygen rearrangement, similar to that reported for related vinylsilanes, rather than on remarkable stabilities of tin‐containing primary ozonides as we had previously suggested.
Nanoscale Manipulation of Prednisolone as Electroactive Configuration Using Molecularly Imprinted‐Multiwalled Carbon Nanotube Paste Electrode
Authors: Rezaei Behzad , Mirahmadi‐Zare S. Z.
Published: October 2011

Prednisolone has no suitable configuration for electroactivation in the potential window from −1.2 to +1.5 V. In this paper, a new catalytic application of molecularly imprinted polymers (MIP) was employed to achieve a suitable prednisolone conformation for electrochemical oxidation. Also, MIP as a recognition element improved the selectivity of the sensor for determination of prednisolone. In addition, to improve the sensitivity of the electrode multiwalled carbon nanotubes (MWCNT) were used in the preparation of MIP. Using differential pulse voltammetry (DPV) under optimized conditions, the calibration curve showed a linear dynamic range (0.08–160.00 µM) with a detection limit of 0.05 µM (S/N=3). The modified electrode was successfully applied as prednisolone sensor in real samples such as plasma, urine and pharmaceutical formulation.
Translocation of single‐stranded DNA through the α‐hemolysin protein nanopore in acidic solutions
Authors: de Zoysa Ranulu S. S. , Krishantha D. M. Milan , Zhao Qitao , Gupta Jyoti , Guan Xiyun
Published: October 2011

The effect of acidic pH on the translocation of single‐stranded DNA through the α‐hemolysin pore is investigated. Two significantly different types of events, i.e. deep blockades and shallow blockades, are observed at low pH. The residence times of the shallow blockades are not significantly different from those of the DNA translocation events obtained at or near physiological pH, whereas the deep blockades have much larger residence times and blockage amplitudes. With a decrease in the pH of the electrolyte solution, the percentage of the deep blockades in the total events increases. Furthermore, the mean residence time of these long‐lived events is dependent on the length of DNA, and also varies with the nucleotide base, suggesting that they are appropriate for use in DNA analysis. In addition to being used as an effective approach to affect DNA translocation in the nanopore, manipulation of the pH of the electrolyte solution provides a potential means to greatly enhance the sensitivity of nanopore stochastic sensing.
Impaired Coenzyme A metabolism affects histone and tubulin acetylation in Drosophila and human cell models of pantothenate kinase associated neurodegeneration
Authors: Siudeja Katarzyna , Srinivasan Balaji , Xu Lanjun , Rana Anil , de Jong Jannie , Nollen Ellen A. A. , Jackowski Suzanne , Sanford Lynn , Hayflick Susan , Sibon Ody C. M.
Published: October 2011

Pantothenate kinase‐associated neurodegeneration (PKAN is a neurodegenerative disease with unresolved pathophysiology. Previously, we observed reduced Coenzyme A levels in a Drosophila model for PKAN. Coenzyme A is required for acetyl‐Coenzyme A synthesis and acyl groups from the latter are transferred to lysine residues of proteins, in a reaction regulated by acetyltransferases. The tight balance between acetyltransferases and their antagonistic counterparts histone deacetylases is a well‐known determining factor for the acetylation status of proteins. However, the influence of Coenzyme A levels on protein acetylation is unknown. Here we investigate whether decreased levels of the central metabolite Coenzyme A induce alterations in protein acetylation and whether this correlates with specific phenotypes of PKAN models. We show that in various organisms proper Coenzyme A metabolism is required for maintenance of histone‐ and tubulin acetylation, and decreased acetylation of these proteins is associated with an impaired DNA damage response, decreased locomotor function and decreased survival. Decreased protein acetylation and the concurrent phenotypes are partly rescued by pantethine and HDAC inhibitors, suggesting possible directions for future PKAN therapy development.
The many faces of preparatory control in task switching: Reviewing a decade of fMRI research
Authors: Ruge Hannes , Jamadar Sharna , Zimmermann Uta , Karayanidis Frini
Published: October 2011

A large body of behavioural research has used the cued task‐switching paradigm to characterize the nature of trial‐by‐trial preparatory adjustments that enable fluent task implementation when demands on cognitive flexibility are high. This work reviews the growing number of fMRI studies on the same topic, mostly focusing on the central hypothesis that preparatory adjustments should be indicated by enhanced prefrontal and parietal BOLD activation in task switch when compared with task repeat trials under conditions that enable advance task preparation. The evaluation of this straight‐forward hypothesis reveals surprisingly heterogeneous results regarding both the precise localization and the very existence of switch‐related preparatory activation. Explanations for these inconsistencies are considered on two levels. First, we discuss methodological issues regarding (i) the possible impact of different fMRI‐specific experimental design modifications and (ii) statistical uncertainty in the context of massively multivariate imaging data. Second, we discuss explanations related to the multidimensional nature of task preparation itself. Specifically, the precise localization and the size of switch‐related preparatory activation might depend on the differential interplay of hierarchical control via abstract task goals and attentional versus action‐directed preparatory processes. We argue that different preparatory modes can be adopted relying either on advance goal activation alone or on the advance resolution of competition within action sets or attentional sets. Importantly, while either mode can result in a reduction of behavioral switch cost, only the latter two are supposed to be associated with enhanced switch versus repeat BOLD activation in prepared trial conditions. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.
Implication of Cognitive Style in Designing Computer‐Based Procedure Interface
Authors: Su Kuo‐Wei , Chen Chiu‐Jung , Shue Li‐Yen
Published: October 2011

Different people have different models of mental perception, which form the bases of human reactions. The design of human‐computer interfaces should consider these differences in the cognitive models of users to achieve maximum benefits. The Myers‐Briggs Type Indicator (MBTI) is an accepted tool for measuring four dimensions of an individual's cognitive model. This research investigated the effects of two interface designs based on the characteristics of the Sensing/iNtuitive (S/N) and Thinking/Feeling (T/F) categories. These interfaces were designed for the visual information displays of computer‐based procedures at a nuclear power plant. Because of the nature of this industry, quicker reaction times are required and fewer mistakes are tolerated. A group of subjects were selected, and the subjects were assigned to either the ST or NT group before the experiment. The results, when compared with earlier statistics for a single design for all users, indicate that reaction times were reduced in some critical situations and the number of mistakes was reduced. © 2011 Wiley Periodicals, Inc.
Ocular movements under taskload manipulations: Influence of geometry on saccades in air traffic control simulated tasks
Authors: Marchitto Mauro , Di Stasi Leandro Luigi , Cañas José Juan
Published: October 2011

Traffic geometry is a factor that contributes to cognitive complexity in air traffic control. In conflict‐detection tasks, geometry can affect the attentional effort necessary to correctly perceive and interpret the situation; online measures of situational workload are therefore highly desirable. In this study, we explored whether saccadic movements vary with changes in geometry. We created simple scenarios with two aircraft and simulated a conflict detection task. Independent variables were the conflict angle and the distance to convergence point. We hypothesized lower saccadic peak velocity (and longer duration) for increasing complexity, that is, for increasing conflict angles and for different distances to convergence point. Response times varied accordingly with task complexity. Concerning saccades, there was a decrease of peak velocity (and a related increase of duration) for increased geometry complexity for large saccades (>15°). The data therefore suggest that geometry is able to influence “reaching” saccades and not “fixation” saccades. © 2011 Wiley Periodicals, Inc.
The roles of extracellular signal‐regulated kinase 1/2 pathway in regulating osteogenic differentiation of murine preosteoblasts MC3T3‐E1 cells on roughened titanium surfaces
Authors: Zhuang Long‐Fei , Jiang Huan‐Huan , Qiao Shi‐Chong , Appert Christoph , Si Mi‐si , Gu Ying‐Xin , Lai Hong‐Chang
Published: October 2011

Surface roughness of titanium‐based implants may enhance osteogenic differentiation of cells in vitro and bone‐to‐implant contact in vivo. Nevertheless, how surface roughness regulates the signaling pathway of osteoblasts is little understood. The study intended to investigate specifically the roles of extracellular signal‐regulated kinase 1/2 (ERK1/2) pathway in regulating osteogenic differentiation of MC3T3‐E1 murine preosteoblast cells on Ti surfaces. Substrates applied were two groups of titanium disks: (1) sand‐blasted and acid‐etched rough surfaces (SLA) and (2) smooth pretreated Ti surfaces (PT). Surface morphology of the two groups was examined by scanning electron microscope, and cell morphology cultured on Ti disks was observed by confocal microscope. The levels of alkaline phosphatase (ALP) activity and calcium deposition were measured and compared between the two groups. Real‐time polymerase chain reaction was applied to detect the expression levels of osteogenic genes including runt related protein 2 (Runx2), osterix (OSX), osteocalcin (OCN) and osteoprotegerin (OPN) of the cells cultured on the two groups of substrates and on SLA surfaces treated with ERK1/2 inhibitor, PD98095. ERK1/2 activities in MC3T3‐T1 cells were measured by Western‐blotting on the two surfaces with or without PD98095. Cells cultured on rougher SLA surfaces displayed a more differentiated morphology. ALP activities at 7 days and 14 days and the calcium deposition at 28 days were significantly higher on SLA surfaces. The expression levels of Runx2, OSX, OPN and OCN were upregulated by the effect of surface roughness and PD98095 further upregulated the expression levels of these osteogenic genes on SLA surfaces. ERK1/2 phosphorylation was continuously inhibited by surface roughness at 2 days, 4 days and 6 days. In contrast, no marked alterations in ERK1/2 phosphorylation on PT surfaces were observed. PT surfaces treated with PD98095 (50 μM) and SLA surfaces without PD98095 both demonstrated reduced ERK1/2 phosphorylation of the cells, and the inhibitive effect of SLA surfaces was milder than that of PD98095. In conclusion, ERK1/2 pathway may be a negative regulator of cell differentiation in a dosage‐dependent manner, and the enhancing effect of surface roughness on osteoblastic differentiation may be mediated through inhibiting ERK1/2 pathway. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Alignment of human vascular smooth muscle cells on parallel electrospun synthetic elastin fibers
Authors: Nivison‐Smith Lisa , Weiss Anthony S.
Published: October 2011

We generated parallel elastic fibers from synthetic elastin (SE) as a model of the arterial media and assessed the alignment of smooth muscle cells (SMCs). SE utilized crosslinked electrospun human tropoelastin to form aligned fibers that mimicked the topography and elastin‐rich content of the medial extracellular matrix. Bundled parallel fibers were anisotropically more elastic than randomly arranged scaffolds (111 ± 25 kPa vs. 265 ± 17 kPa) in the direction of the fibers. Aligned and random fiber scaffolds each supported SMC growth. Following attachment, SMCs proliferated longitudinally on the parallel fibers and expressed native α‐smooth muscle actin. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Molecular dynamics simulation of hydrated DPPC monolayers using charge equilibration force fields
Authors: Lucas Timothy R. , Bauer Brad A. , Davis Joseph E. , Patel Sandeep
Published: October 2011

We present results of molecular dynamics simulations of a model DPPC‐water monolayer using charge equilibration (CHEQ) force fields, which explicitly account for electronic polarization in a classical treatment of intermolecular interactions. The surface pressure, determined as the difference between the monolayer and pure water surface tensions at 323 K, is predicted to be 22.92 ±1.29dyne/cm, just slightly below the broad range of experimental values reported for this system. The surface tension for the DPPC‐water monolayer is predicted to be 42.35 ±1.16dyne/cm, in close agreement with the experimentally determined value of 40.9 dyne/cm. This surface tension is also consistent with the value obtained from DPPC monolayer simulations using state‐of‐the‐art nonpolarizable force fields. The current results of simulations predict a monolayer‐water potential difference relative to the pure water‐air interface of 0.64 ±0.02 Volts, an improved prediction compared to the fixed‐charge CHARMM27 force field, yet still overestimating the experimental range of 0.3 to 0.45 Volts. As the charge equilibration model is a purely charge‐based model for polarization, the current results suggest that explicitly modeled polarization effects can offer improvements in describing interfacial electrostatics in such systems. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Variable bright‐darkfield‐contrast, a new illumination technique for improved visualizations of complex structured transparent specimens
Authors: Piper Timm , Piper Jörg
Published: October 2011

Variable bright‐darkfield contrast (VBDC) is a new technique in light microscopy which promises significant improvements in imaging of transparent colorless specimens especially when characterized by a high regional thickness and a complex three‐dimensional architecture. By a particular light pathway, two brightfield‐ and darkfield‐like partial images are simultaneously superimposed so that the brightfield‐like absorption image based on the principal zeroth order maximum interferes with the darkfield‐like reflection image which is based on the secondary maxima. The background brightness and character of the resulting image can be continuously modulated from a brightfield‐dominated to a darkfield‐dominated appearance. When the weighting of the dark‐ and brightfield components is balanced, medium background brightness will result showing the specimen in a phase‐ or interference contrast‐like manner. Specimens can either be illuminated axially/concentrically or obliquely/eccentrically. In oblique illumination, the angle of incidence and grade of eccentricity can be continuously changed. The condenser aperture diaphragm can be used for improvements of the image quality in the same manner as usual in standard brightfield illumination. By this means, the illumination can be optimally adjusted to the specific properties of the specimen. In VBDC, the image contrast is higher than in normal brightfield illumination, blooming and scattering are lower than in standard darkfield examinations, and any haloing is significantly reduced or absent. Although axial resolution and depth of field are higher than in concurrent standard techniques, the lateral resolution is not visibly reduced. Three dimensional structures, reliefs and fine textures can be perceived in superior clarity. Microsc. Res. Tech. 2011. © 2011 Wiley‐Liss, Inc.
Novel boundary conditions for strain localization analyses in microstructural volume elements
Authors: Coenen E.W.C. , Kouznetsova V.G. , Geers M.G.D.
Published: October 2011

Multi‐scale modeling frequently relies on microstructural representative volume elements (RVEs) on which macroscopic deformation is imposed through kinematical boundary conditions. A particular choice of these boundary conditions may influence the obtained effective properties. For strain localization and damage analyses, the RVE is pushed beyond the limits of its representative character, and the applied boundary conditions have a significant impact on the onset and the type of macroscopic material instability to be predicted.

In this article, we propose a new type of boundary conditions for microstructural volume elements, called percolation‐path‐aligned boundary conditions. Intrinsically, these boundary conditions capture the constraining effect of the material surrounding the RVE upon developing localization bands. The alignment with evolving localization bands allows the highly strained band to cross the RVE and fully develop with minimal interference of the applied boundary conditions. For an illustration of the performance of the newly proposed boundary conditions, macroscopic deformation has been imposed on a voided elasto‐plastic RVE using different types of boundary conditions. It is observed that the new RVE boundary conditions provide a good estimate for the effective stiffness, are not susceptible to spurious localization, and permit the development of a full strain localization band up to failure. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of annealing on the microstructure and mechanical properties of polypropylene with oriented shish‐kebab structure
Authors: Bai Hongwei , Deng Hua , Zhang Qin , Wang Ke , Fu Qiang , Zhang Zhijie , Men Yongfeng
Published: October 2011

Annealing is thought to be an effective method to promote chain rearrangement in semicrystalline polymers and improve their physical properties. However, little attention has been paid to the annealing of flow‐oriented semicrystalline polymers despite its importance in polymer processing. In this work, the microstructural evolution of injection‐moulded polypropylene with an oriented shish‐kebab structure upon annealing has been explored with differential scanning calorimetry, small‐angle X‐ray scattering and scanning electron microscopy, Fourier transform infrared spectroscopy and dynamic mechanical analysis. The results show that annealing gives rise to a chain rearrangement in both the crystalline and amorphous phases. Accompanied by the growth and perfecting of the kebabs, relaxation of the initially oriented chains in the amorphous phase is observed. Then, the relationship between the structure and the resulting mechanical properties is established. Copyright © 2011 Society of Chemical Industry
Rheological properties of homogeneous and heterogeneous poly(2‐hydroxyethyl methacrylate) hydrogels
Authors: Karpushkin Evgeny , Dušková‐Smrčková Miroslava , Remmler Torsten , Lapčíková Monika , Dušek Karel
Published: October 2011

The swelling and rheological behaviour of hydrogels of morphology varying from non‐porous to highly porous was investigated. The hydrogels were prepared by redox free radical copolymerization of 2‐hydroxyethyl methacrylate with 0.1 to 5 mol% of di(ethylene glycol) dimethacrylate in the presence of water varying from 40 to 80 wt%. Various compositions led to clear, turbid or macroporous gels. The morphology of the gels was characterized using optical microscopy and cryoscan electron microscopy. The oscillatory shear and creep of swollen gels revealed that there was a pronounced difference between homogeneous or microheterogeneous and macroporous gels with communicating pores. The achievement of optimum conditions for the correct determination of shear modulus was also analysed. Copyright © 2011 Society of Chemical Industry
Short range correlations of misfit dislocations in the X‐ray diffraction peaks
Authors: Kaganer Vladimir M. , Sabelfeld Karl K.
Published: October 2011

The X‐ray diffraction peak profiles due to misfit dislocations are studied for the dislocations correlated on distances much smaller than the film thickness. Simple analytical expressions for the correlation parameter are obtained when the dislocations are generated as a Markov chain. Monte Carlo calculations show the peak profile evolution as order in the dislocation positions increases.
The Variable Sample Size Chart with Estimated Parameters
Authors: Castagliola Philippe , Zhang Ying , Costa Antonio , Maravelakis Petros
Published: October 2011

The VSS chart, dedicated to the detection of small to moderate mean shifts in the process, has been investigated by several researchers under the assumption of known process parameters. In practice, the process parameters are rarely known and are usually estimated from an in‐control Phase I data set. In this paper, we evaluate the (run length) performances of the VSS chart when the process parameters are estimated, we compare them in the case where the process parameters are assumed known and we propose specific optimal control chart parameters taking the number of Phase I samples into account.
Exactly solvable schrödinger equation for a class of multiparameter exponential‐type potentials
Authors: García‐Martínez J. , García‐Ravelo J. , Morales J. , Peña J. J.
Published: October 2011

The solution to a spectral problem involving the Schrödinger equation for a particular class of multiparameter exponential‐type potentials is presented. The proposal is based on the canonical transformation method applied to a general second‐order differential equation, multiplied by a functiong(x), to convert it into a Schrödinger‐like equation. The treatment of multiparameter exponential‐type potentials comes from the application of the transformed results to the hypergeometric equation under the assumption of a specificg(x). Besides presenting the explicit solutions and their spectral values, it is shown that the problem considered in this article unifies and generalizes several former studies. That is, the proposed exactly solvable multiparameter exponential‐type potential can be straightforwardly applied to particular exponential potentials depending on the choice of the involved parameters as exemplified for the Hulthén potential and their isospectral partner. Moreover, depending on the functiong(x), the proposal can be extended to find different exactly solvable potentials as well as to generate new potentials that could be useful in quantum chemical calculations. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Structure and reactivity of the mixed‐valence CaMn4O5(H2O)4 and CaMn4O4(OH)(H2O)4 clusters at oxygen evolution complex of photosystem II. Hybrid DFT (UB3LYP and UBHandHLYP) calculations
Authors: Yamanaka S. , Saito T. , Kanda K. , Isobe H. , Umena Y. , Kawakami K. , Shen J.‐R. , Kamiya N. , Okumura M. , Nakamura H. , Yamaguchi K.
Published: October 2011

Very recently Umena et al. have determined the X‐ray diffraction (XRD) structure of the CaMn4O5 cluster in the oxygen evolution complex (OEC) of photosystem II (PSII) refined to 1.9 Å resolution. We have performed theoretical attempts to elucidate possible electronic and spin states of their new XRD structure of the CaMn4O5 cluster. For the purpose, hybrid density functional theory (UB3LYP and UBHandHLYP) calculations have been performed for the mixed‐valence (MV) CaMn(III)4‐ω(IV)ωO5(H2O)4 (1) and CaMn(III)4‐ω(IV)ωO4(OH)(H2O)4 (2) clusters as active catalytic site for water splitting reaction in OEC of PSII. Full geometry optimizations of 1a (ω = 2) and 2a (ω = 2) have been performed to elucidate scope and limitation of the cluster models. Both charge and spin fluctuated structures (48 UB3LYP solutions) have been considered for the MV 1a (ω = 2). Total energies obtained by these calculations have elucidated quasi‐degenerated electronic and spin states that are characterized by charge and spin density populations. The energy levels revealed by hybrid DFT are analyzed on the basis of the Heisenberg spin Hamiltonian model, providing the effective exchange integrals between manganese ions at a uniform or MV structure. The spin projections for hybrid DFT solutions are performed using the effective exchange integrals. The charge fluctuation model is introduced to analyze relative stabilities among MV structures of 1a and 2a. These computational results for 1a and 2a have explored several characteristic electronic properties of the species that are used for theoretical elucidation of possible mechanisms of water splitting reaction. Orbital and spin correlation diagrams are derived for the OO bond formation and oxygen evolution in the reaction. Implications of the computational results are also discussed in relation to available experiments and theoretical results by other groups. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
A two‐stage mixed‐effects model approach for gene‐set analyses in candidate gene studies
Authors: Tsonaka Roula , van der Helm‐van Mil Annette H. M. , Houwing‐Duistermaat Jeanine J.
Published: October 2011

In genetic association studies, a gene‐set analysis can be more powerful than the separate analyses of multiple genetic variants and can offer unique insights into the genetic basis of many common human diseases. The goal of such an analysis is to study the joint effect of multiple single‐nucleotide polymorphisms (SNPs) which belong to certain genes, and these genes are assumed to be involved in a common biological function. Currently, few approaches acknowledge the within‐genes and between‐genes correlations when testing for gene‐set effects. Thus, here we propose a two‐stage approach, which in the first stage uses a mixed‐effects model with a general random‐effects structure to capture the correlation between the SNPs and in the second stage tests for gene‐set effects by using the empirical Bayes estimates of the random effects of the first stage as covariates in the model for the longitudinal phenotype. The advantage of this approach is its broad applicability because it can be used for any phenotypic outcome and any genetic model and can be implemented with standard statistical software. Copyright © 2011 John Wiley & Sons, Ltd.
The Exocytosis of Fluorescent Nanodiamond and Its Use as a Long‐Term Cell Tracker
Authors: Fang Chia‐Yi , Vaijayanthimala V. , Cheng Chi‐An , Yeh Shih‐Hua , Chang Ching‐Fang , Li Chung‐Leung , Chang Huan‐Cheng
Published: October 2011

Fluorescent nanodiamond (FND) has excellent biocompatibility and photostability, making it well suited for long‐term labeling and tracking of cancer and stem cells. To prove the concept, the exocytosis of FND particles (size ≈100 nm) from three cell lines—HeLa cervical cancer cells, 3T3‐L1 pre‐adipocytes, and 489‐2.1 multipotent stromal cells—is studied in detail. FND labeling is performed by incubating the cells in a serum‐free medium containing 80 μg mL−1 FND for 4 h. No significant alteration in growth or proliferation of the FND‐labeled cells, including the multipotent stromal cells, is observed for up to 8 days. Flow cytometric analysis, in combination with parallel cell doubling‐time measurements, indicates that there is little (≈15% or less) excretion of the endocytosed FND particles after 6 days of labeling for both HeLa and 489‐2.1 cells, but exocytosis occurs more readily (up to 30%) for 3T3‐L1 preadipocytes. A comparative experiment with FND and the widely used dye, carboxyfluorescein diacetate succinimidyl ester, demonstrates that the nanoparticle platform is a promising alternate probe for long‐term cell labeling and tracking applications.
Snakes all the Way Down: Varela's Calculus for Self‐Reference and the Praxis of Paradise
Authors: Reichel André
Published: October 2011

This contribution seeks to commemorate Francisco Varela's formal conceptions of self‐reference, providing an overview of his writings while shedding some light in the praxis of self‐reference, from where a future research agenda can be derived. The architecture of Varela's thinking, determined by the interrelated notions of autopoiesis, autonomy, closure and self‐reference, was examined. The emphasis was on the development and expansions of his calculus for self‐reference from George Spencer Brown's Laws of Form. After dealing with some of the criticism launched at both works, an appraisal of the praxis of self‐reference of Varela's thinking in action was given. The outlook rounds up this contribution, shedding some light on a possible future research agenda for the formalization of theory and praxis of self‐reference. Copyright © 2011 John Wiley & Sons, Ltd.