bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of starting microstructure on austenite grain sizes developed after reheating of HSLA steel
Authors: Roy S. , Karmakar A. , Mukherjee S. , Kundu S. , Srivastava D. , Chakrabarti D.
Published: October 2013

Austenite grain structure has been studied over a wide range of soaking temperatures (950–1250°C) in a high strength low alloy steel containing Nb, Ti and V for different starting conditions, namely as cast, hot rolled and thermomechanical controlled rolled. Mixed (or bimodal) austenite grain structures were developed as a result of abnormal grain growth at different soaking temperatures in as cast slab (∼1200°C) and in rolled plates (∼1000°C), which has hardly been reported earlier. Higher fraction of finer precipitates, such as NbC and VC (<200 nm in size), were present in the rolled plate as compared to as cast slab, where the precipitates were coarser and complex in nature. Rapid dissolution of fine VC precipitates was primarily responsible for the observed abnormal grain growth in rolled plates at lower soaking temperature (∼1000°C). Coarse precipitates of complex nature, such as (Nb,Ti,V)(C,N) and (Nb,Ti)(C,N), remained stable up to ∼1150°C and restricted the formation of abnormal grain growth in as cast steel.
Cellular automaton modelling of dynamic recrystallisation microstructure evolution during friction stir welding of titanium alloy
Authors: Song K. J. , Dong Z. B. , Fang K. , Zhan X. H. , Wei Y. H.
Published: October 2013

It is of great importance to study how the process parameters influence the continuum flow properties and mesomicrostructural features during friction stir welding (FSW) of titanium alloys. In the present paper, microstructure evolution of dynamic recrystallisation (DRX) was simulated by cellular automaton method based on metal plastic flow analysis. The established model can accomplish multiscale modelling of macroscopical plastic flow behaviour, mesostructural dislocation activities, microstructural grain growth dynamics and finally mechanical property of the FSW joint. The predicted flow stress curves are similar with that experimentally measured. Influences of strain rate and temperature on the evolution of the average dislocation density (equivalent to flow stress) as well as the final grain size are analysed, which are in good agreement with classic DRX theories. Final grain size results from the contrary effect of strain rate and temperature, while the strain rate with higher gradient in the welded joint has greater influence. According to the prediction result, a lot of options can be made on matching of marching speed and rotation speed to maintain refined microstructure.
Calculating post-uniform deformation energy using tensile parameters
Authors: Khani Moghanaki S. , Pouraliakbar H. , Jandaghi M. R. , Bagheri R. , Khalaj G.
Published: October 2013

Post-uniform deformation energy of materials is defined as absorbed energy per unit area after necking. The energy is constant for a material type and its experienced specific processing history and also depends on its mechanical parameters as workhardening exponent, strain rate sensitivity, post-necking extension and inhomogeneity factor. Different methods such as single and multiple tensile testing had been proposed in the literature to calculate tearing energy, but the effect of post-necking extension had not been expressed explicitly. A new model by implementing uniform and failure elongations with the combination of Unwin theory is introduced. Based on the model, it was shown that tearing energy was a constant portion of uniform deformation energy in every specific material, and its value for alloys of aluminium, copper and brass was calculated through previous and new developed models.
Shear band structure in ballistically tested bainitic steels
Authors: Fielding L. C. D. , Bhadeshia H. K. D. H.
Published: October 2013

Adiabatic shear bands represent intense plastic deformation that is localised because the rate at which the heat generated by deformation is greater than that at which it is dissipated. The structure of such bands generated by ballistic testing is examined in order to reveal the governing mechanisms. We attempt to distinguish in particular whether local reaustenitisation occurs, or if the microstructural changes are simply a reflection of intense deformation.
Modified twinning behaviour induced by texture evolution in hot rolled Mg–3Al–1Zn alloy
Authors: Xu S. , Liu T. , Gan W. , Tan A. , Wang J.
Published: October 2013

Compressive deformation along the rolling direction (RD) of a hot rolled Mg–3Al–1Zn alloy is applied to investigate the texture evolution and the recompressive yield strength (RYST) along the transverse direction (TD). Preferential orientation of the basal and prismatic planes is generated by the plastic deformation. Precompression along RD results in one plane of {10–10} aligned nearly perpendicular to the normal direction to the rolling plane. As the compressive strain along RD increases, the RYST shows an earlier raised and later decreased trend. The modified twinning mechanism is investigated using X-ray diffraction and electron backscattered diffraction observations. The results reveal that {10–12} twinning in the matrix dominates the recompression along TD, while the formation of {10–12}–{10–12} twins becomes comparatively easier to occur in the previous {10–12} twins for large precompressed samples.
Effect of cast and extruded stock on grain structure of EN AW 6082 alloy forgings
Authors: Birol Y. , Ilgaz O.
Published: October 2013

There has been a rapid increase in the use of aluminium forgings in the automotive industry, where weight savings is a critical requirement for reduced fuel consumption and exhaust emissions. Extruded bar is the typical forging stock particularly in the manufacture of suspension components. There has been a great interest to replace the extruded forging stock with cast billets of the same diameter. The casting and extrusion routes for the manufacture of EN AW 6082 alloy forging stock were compared in the present work. The control arm produced via forging of the cast stock offers a very uniform grain structure and much superior surface quality with respect to its counterpart produced by the forging of the extruded stock owing to a much smaller grain structure at the surface of the forged component after the T6 heat treatment.
Effects of melt superheat treatment on microstructure and wear behaviours of hypereutectic Al–20Si alloy
Authors: Li Q. L. , Xia T. D. , Lan Y. F. , Li P. F.
Published: October 2013

In the present study, the effects of melt superheat treatment on the microstructural evolution and wear behaviours of hypereutectic Al–20Si alloy were investigated. The morphology of primary and eutectic Si phase was analysed by optical microscopy (OM) and scanning electron microscopy (SEM). The results of OM and SEM reveal that increasing the melt superheat temperature can significantly refine the primary and eutectic Si of hypereutectic Al–20Si alloy. The average size of primary Si was reduced from 94 to 47 μm, and its morphology was transformed from coarse and irregular shape to fine blocky shape or particles, while the eutectic Si was modified into fine fibrous structure. The differential scanning calorimeter curves show an exothermic reaction happens when the melt temperature arrives at 940·5°C, and the exothermic peak is at 951°C. Friction and wear tests show that the friction coefficient and specific wear rate of Al–20Si alloy gradually decrease with increasing melt superheat treatment temperature. In addition, the wear mechanism of hypereutectic Al–20Si alloy before and after refining the primary and eutectic Si phase was also discussed.
First principles prediction of structural stability, elastic, lattice dynamical and thermal properties of osmium carbides
Authors: Deligoz E. , Ozisik H. B. , Colakoglu K. , Ciftci Y. O.
Published: October 2013

First principles calculations are performed to investigate the structural stability, elastic, lattice dynamical and thermal properties of osmium carbides with various crystal structures. Our calculation indicates that the I4Te type structure is energetically the most favourable for Os4C. Based on stress–strain relationships, elastic constants are obtained, and the relevant mechanical properties are also discussed. The phonon dispersion relation and the dynamical stability are also predicted. We have found that the predicted structures are mechanically stable as well as dynamically stable except for cubic-Os4C. Through the quasi-harmonic Debye model, the temperature and pressure effects on the bulk modulus, thermal expansion coefficient, heat capacity, Grüneisen parameter and Debye temperature are presented.
Thermal stability of ultrafine grained aluminium alloy prepared by large strain extrusion machining
Authors: Deng W. J. , Li Q. , Li B. L. , Xie Z. C. , He Y. T. , Tang Y. , Xia W.
Published: October 2013

In the present study, ultrafine grained (UFG) Al alloy chips with average grain sizes of ∼200 nm were successfully prepared by large strain extrusion machining (LSEM) process using a combined cutting tool with rake angle of 10° and chip compression ratio of 1.0. The tests showed that the Vickers hardness of the UFG Al alloy is significantly improved due to grain size reduction. To understand effect of heat on the microstructure and mechanical properties, the UFG chips were subjected to heat treatment at different temperatures and different annealing time durations. When annealed <100°C, most of fine grains within the UFG chips were found to be replaced by elongated grains whose grain sizes increased with a significant increase in the aspect ratio as the annealing time increased. Despite such increase in grain size, the Vickers hardness was not reduced as expected because of the precipitation of secondary phases. When annealed at temperatures up to 200°C, recrystallisation occurred, along with grain growth, but the Vickers hardness did not deteriorate because of precipitation of secondary phases, as before. However, annealing at temperatures of 300°C and above resulted in significant reduction in hardness of the chips due to dominance of grain growth over secondary precipitation. These results indicated that UFG Al alloy chips have a good thermal stability at temperatures <200°C.
Phase transformation and microstructure and mechanical properties of as cast NiTiRe shape memory alloys
Authors: El-Bagoury N. , Nofal A. A.
Published: October 2013

The microstructure, martensitic transformation and mechanical properties of as cast Ni52Ti48−xRex shape memory alloys (SMAs) were investigated. The microstructure of these alloys consists of B19′ martensite phase as a matrix and B2 austenite in small percentages in addition to some precipitations of NiTi intermetallic compounds. There are two types of NiTi precipitates: the first one is Ti2Ni, which can be seen in the all microstructures of the three alloys, and the other is Ni2Ti, which is found only in the microstructure of Ni52Ti47·7Re0·3 alloy. According to differential scanning calorimetry measurements, one stage of transformation reaction B2 to B19′ accompanied with forward and backward martensitic transformation was observed. The martensitic peak and the austenitic peak were increased with the addition of rhenium. Both are increased as the number of valence electron per atom increase and the valence electron concentration decrease. Hardness measurements of Ni52Ti48−xRex SMAs are improved by the Re additions.
Electrodeposition of Ni matrix composite coatings containing ZrC particles
Authors: Zhang Z. , Wu X. , Jiang C. , Ma N.
Published: October 2013

In this paper, Ni matrix composite coatings containing either micro-ZrC or nano-ZrC particles were successfully prepared by direct current electrodeposition. The microstructure of the coatings, including crystallographic texture and grain size, were studied by X-ray diffraction analysis. Energy dispersive spectrometer and scanning electron microscope were used to investigate the chemical composition and morphology of the coatings. The microhardness of the coatings was measured by a Vicker microhardness tester. Grain refinement strengthening and dispersion strengthening mechanisms were applied to interpret the evolution of the microhardness. The corrosion resistance of the Ni matrix composite coatings was investigated by corrosion polarisation method. The composite coatings exhibit better mechanical property and corrosion resistance than pure Ni coating.
Elastic anisotropy of coatings by AFM analysis of microindentations
Authors: Sebastiani M. , Cusmà A. , Bemporad E. , Carassiti F.
Published: October 2013

Atomic force microscope analysis of low load Vickers and Knoop indentation marks was performed to obtain a statistically consistent method for the mechanical characterisation of physical vapour deposition (PVD) coatings and the evaluation of elastic anisotropy. Indents shape analysis were elaborated with three different models for the evaluation of Young's modulus. Subsequently, roughness, elastic/plastic behaviour and intrinsic hardness have been numerically evaluated. Results showed that the intrinsic hardness evaluation of the films for applied loads as low as 50 mN is statistically supported by atomic force microscopy analysis of the indents, especially when diagonal length is smaller than 2/3 m. Moreover, some of magnetron sputtering PVDPlease confirm definition of MS. coatings showed mechanical anisotropy: normal to surface Young's modulus was higher than in plane Young's modulus. Such information would not have been obtained by nanoindentation testing alone and could be extremely important for the process development and production of high performance coatings for specific tribological applications
Erosion behaviour of NiCrBSi coating under mining conditions
Authors: Yoganandh J. , Natarajan S. , Kumaresh Babu S. P.
Published: October 2013

Grey cast iron material was taken up for the investigation with and without the application of NiCrBSi coating by high velocity oxyfuel process on its substrate. Prominent influencing factors such as velocity and angle of impingement were chosen for the study of the erosive wear behaviour involving two different pH conditions of 3 and 7 that conform to the mining conditions. X-ray diffraction characterisation was used to identify and confirm the phase formation in the coating. Wear morphology was also studied using scanning electron microscopy characterisation techniques. NiCrBSi coating at low angles of impact reveals that the degradation is by shallow ploughing and abrasion. At normal impact, erosion takes place by deep indentation that forms lips and craters, which are subsequently removed as platelets by a fatigue process. In the case of base material, the material removal from the surface is predominantly by ploughing mechanism.
Study on preparation of NiFe films by galvanostatic electrodeposition
Authors: Cao Y. , Wei G. Y. , Ge H. L. , Meng X. F.
Published: October 2013

NiFe alloy films were prepared by galvanostatic electrodeposition method on a copper substrate under various deposition temperature and current density. The structure and surface morphology of electrodeposited NiFe films were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Vibrating sample magnetometer and electrochemical workstation was used to obtain the magnetic and corrosion behaviours of the NiFe thin film. The results showed that the NiFe particle size was ranging from 10 to 30 nm. The main phase of NiFe thin films was fcc (FeNi3) structure. NiFe thin films prepared under the condition of temperature (60°C) and current density (167 A m−2) possessed low coercivity (0·18 kA m−1) and high specific saturation magnetisation (253 Am2 kg−1).
Influence of thermocycle boroaluminising on strength of steel C30
Authors: Sizov I. , Mishigdorzhiyn U. , Leyens C. , Vetter B. , Fuhrmann T.
Published: October 2013

The article describes the research results of steel C30 boroaluminised by isothermal and thermocycle methods in powder mixtures. Thermocycling is performed in the range of 650–950°C. In this study, a comparative analysis of microstructure, composition of elements and microhardness of boroaluminised steels after various treatments is presented. A series of tensile tests and a plasticity estimation of boroaluminised layer were carried out.
Candidemia in the critically ill: initial therapy and outcome in mechanically ventilated patients
Authors: Ferrada Marcela A , Quartin Andrew A , Kett Daniel H , Morris Michele I
Published: October 2013

Background

Mortality among critically ill patients with candidemia is very high. We sought to determine whether the choice of initial antifungal therapy is associated with survival among these patients, using need for mechanical ventilatory support as a marker of critical illness.

Methods

Cohort analysis of outcomes among mechanically ventilated patients with candidemia from the 24 North American academic medical centers contributing to the Prospective Antifungal Therapy (PATH) Alliance registry. Patients were included if they received either fluconazole or an echinocandin as initial monotherapy.

Results

Of 5272 patients in the PATH registry at the time of data abstraction, 1014 were ventilated and concomitantly had candidemia, with 689 eligible for analysis. 28-day survival was higher among the 374 patients treated initially with fluconazole than among the 315 treated with an echinocandin (66% versus 51%, P < .001). Initial fluconazole therapy remained associated with improved survival after adjusting for non-treatment factors in the overall population (hazard ratio .75, 95% CI .59–.96), and also among patients with albicans infection (hazard ratio .62, 95% CI .44–.88). While not statistically significant, fluconazole appeared to be associated with higher mortality among patients infected with glabrata (HR 1.13, 95% CI .70–1.84).

Conclusions

Among ventilated patients with candidemia, those receiving fluconazole as initial monotherapy were significantly more likely to survive than those treated with an echinocandin. This difference persisted after adjustment for non-treatment factors.
Factors associated with receipt of adjuvant chemotherapy among married women with breast cancer
Authors: Zhang Yan , Gao Hua , Bu Yulan , Fan Xiuzhen , Jia Jihui
Published: October 2013

Background

Adjuvant chemotherapies are recommended for most women after breast cancer surgery, and can greatly affect the patients’ survival. We describe and evaluate possible factors influencing receipt of postoperative adjuvant chemotherapy among breast cancer patients in China.

Methods

A total of 1,431 women diagnosed with breast cancer from 1997 to 2005 were enrolled. We reviewed medical records and abstracted information about these patients. Details on social-demographic factors and clinical-pathological characteristics of participants were collected and analyzed. To meet our objectives, the patient’s age at diagnosis, comorbidities, menstrual status, rural/urban status, tumor size, lymph node status, distant metastasis, tumor stage and hormone receptor status were estimated.

Results

Overall, 936 of these 1,431 patients (65.41%) received adjuvant chemotherapy. Receipt of chemotherapy was significantly associated with age at diagnosis, rural–urban disparities, and lymph node status of patients, though no significant difference was found between the age <50 and age 50 to 64 groups. Moderate association was also observed between hormone receptor status and receipt of adjuvant chemotherapy, though it was still not statistically significant.

Conclusions

Our study suggests that age at diagnosis, rural–urban disparities and lymph node status of breast cancer patients are independent predictors for receipt of adjuvant chemotherapy among married Chinese women. Further investigations are warranted, and related public health education needs to be expanded in China.
Fluorescence energy transfer in quantum dot/azo dye complexes in polymer track membranes
Authors: Gromova Yulia A , Orlova Anna O , Maslov Vladimir G , Fedorov Anatoly V , Baranov Alexander V
Published: October 2013

Fluorescence resonance energy transfer in complexes of semiconductor CdSe/ZnS quantum dots with molecules of heterocyclic azo dyes, 1-(2-pyridylazo)-2-naphthol and 4-(2-pyridylazo) resorcinol, formed at high quantum dot concentration in the polymer pore track membranes were studied by steady-state and transient PL spectroscopy. The effect of interaction between the complexes and free quantum dots on the efficiency of the fluorescence energy transfer and quantum dot luminescence quenching was found and discussed.
Neurochemical Characterisation of Lamina II Inhibitory Interneurons that Express GFP in the PrP-GFP Mouse
Authors: Iwagaki Noboru , Garzillo Francesca , Polgár Erika , Riddell John S , Todd Andrew J
Published: October 2013

Background

Inhibitory interneurons in the superficial dorsal horn play important roles in modulating sensory transmission, and these roles are thought to be performed by distinct functional populations. We have identified 4 non-overlapping classes among the inhibitory interneurons in the rat, defined by the presence of galanin, neuropeptide Y, neuronal nitric oxide synthase (nNOS) and parvalbumin. The somatostatin receptor sst2A is expressed by −50% of the inhibitory interneurons in this region, and is particularly associated with nNOS- and galanin-expressing cells. The main aim of the present study was to test whether a genetically-defined population of inhibitory interneurons, those expressing green fluorescent protein (GFP) in the PrP-GFP mouse, belonged to one or more of the neurochemical classes identified in the rat.

Results

The expression of sst2A and its relation to other neurochemical markers in the mouse was similar to that in the rat, except that a significant number of cells co-expressed nNOS and galanin. The PrP-GFP cells were entirely contained within the set of inhibitory interneurons that possessed sst2A receptors, and virtually all expressed nNOS and/or galanin. GFP was present in ˜3–4% of neurons in the superficial dorsal horn, corresponding to ˜16% of the inhibitory interneurons in this region. Consistent with their sst2A-immunoreactivity, all of the GFP cells were hyperpolarised by somatostatin, and this was prevented by administration of a selective sst2 receptor antagonist or a blocker of G-protein-coupled inwardly rectifying K+ channels.

Conclusions

These findings support the view that neurochemistry provides a valuable way of classifying inhibitory interneurons in the superficial laminae. Together with previous evidence that the PrP-GFP cells form a relatively homogeneous population in terms of their physiological properties, they suggest that these neurons have specific roles in processing sensory information in the dorsal horn.
The relationship between drive to thinness, conscientiousness and bulimic traits during adolescence: a comparison between younger and older cases in 608 healthy volunteers
Authors: De Pasquale Concetta , Pistorio Maria Luisa , Tornatore Eleonora , De Berardis Domenico , Fornaro Michele
Published: October 2013

Background

Adolescence represents one of the critical transitions in the life span and is characterized by a tremendous pace in growth and change that is second only to that of infancy. Both biological and psychological changes occurring during early adolescence may also influence the definition of subsequent late adolescence or early adulthood physiological or (psycho)-pathological features, including bulimia nervosa (BN) whenever occurring. Therefore, a pre-emptive assessment of suggestive psychological traits, including bulimic ones, during early and late years of adolescence, is recommended and represents the goal of the present study.

Methods

Six hundred and eight healthy volunteers attending mid- or high school, aged 14–19 years, were consecutively enrolled at multiple sites in Eastern Sicily, Italy. A systematic psychological assessment was performed, including McCrae and Costa' BigFive, the Eating Disorders Inventory (EDI), Bisantis's Assertivity test and the Liebowitz Social Anxiety Scale for Children and Adolescents. Demographic and general characteristics, including the body mass index, were also recorded. Based on hierarchical considerations, cases were then divided into ‘younger’ (‘early’ years, 14–16) and ‘older’ (‘late’ years, 17–19) adolescents.

Results

Upon descriptive and Pearson's correlation analyses, the following EDI constructs ‘drive to thinness’ and ‘bulimia’ scored significantly higher (both p = <.001) in ‘early’ vs. ‘late’ cases. Conversely, BigFive ‘conscientiousness’ was higher in older subjects vs. early cases (p = <.003). As expected, ‘drive to thinness’ positively correlated with BN both in early (r = .31) and late (r = .50) cases. In the ‘late’ group, age correlated with conscientiousness (r = .206) while BN correlated with drive to thinness (r = .505); finally, a negative correlation was observed with regard to consciousness and BN (r = −.19).

Conclusions

Despite intrinsic methodological limits, our preliminary findings confirm that the transition between early and late years of adolescence is a critical phase of life span, with the consolidation of ‘conscientiousness’ eventually playing a protective role towards the onset of bulimic traits. If confirmed by replication studies, ideally providing long-term follow-ups too, an early acknowledgement of bulimic traits may play a major predictive role for subsequent BN, ultimately contributing to more effective pre-emptive interventions as well.
Evaluation of multi‐segmental kinematic modelling in the paediatric foot using three concurrent foot models
Authors: Mahaffey Ryan , Morrison Stewart C , Drechsler Wendy I , Cramp Mary C
Published: October 2013

Background

Various foot models are used in the analysis of foot motion during gait and selection of the appropriate model can be difficult. The clinical utility of a model is dependent on the repeatability of the data as well as an understanding of the expected error in the process of data collection. Kinematic assessment of the paediatric foot is challenging and little is reported about multi‐segment foot models in this population. The aim of this study was to examine three foot models and establish their concurrent test‐retest repeatability in evaluation of paediatric foot motion during gait.

Methods

3DFoot, Kinfoot and the Oxford Foot Model (OFM) were applied concurrently to the right foot and lower limb of 14 children on two testing sessions. Angular data for foot segments were extracted at gait cycle events and peaks and compared between sessions by intraclass correlation coefficient (ICC) with 95% confidence intervals (95%CI) and standard error of measurement (SEM).

Results

All foot models demonstrated moderate repeatability: OFM (ICC 0.55, 95% CI 0.16 to 0.77), 3DFoot (ICC 0.47, 95% CI 0.15 to 0.64) and Kinfoot (ICC 0.43, 95% CI ‐0.03 to 0.59). On the basis of a cut‐off of 5°, acceptable mean error over repeated sessions was observed for OFM (SEM 4.61° ± 2.86°) and 3DFoot (SEM 3.88° ± 2.18°) but not for Kinfoot (SEM 5.08° ± 1.53°). Reliability of segmental kinematics varied, with low repeatability (ICC < 0.4) found for 14.3% of OFM angles, 22.7% of 3DFoot angles and 37.6% of Kinfoot angles. SEM greater than 5° was found in 26.2% of OFM, 15.2% of 3DFoot, and 43.8% of Kinfoot segmental angles.

Conclusion

Findings from this work have demonstrated that segmental foot kinematics are repeatable in the paediatric foot but the level of repeatability and error varies across the segments of the different models. Information on repeatability and test‐retest errors of three‐dimensional foot models can better inform clinical assessment and advance understanding of foot motion during gait.
Direct observation of cell cycle progression in living mouse embryonic stem cells on an extracellular matrix of E-cadherin
Authors: Jovic Dragomirka , Sakaue-Sawano Asako , Abe Takaya , Cho Chong-Su , Nagaoka Masato , Miyawaki Atsushi , Akaike Toshihiro
Published: October 2013

Self-renewal and differentiation of embryonic stem cells are tightly coordinated with cell-cycle progression and reconstructions. However, technical approach to directly visualize single embryonic stem cells still remains challenging. Here we combined two independent systems by using artificially constructed extracellular matrix that maintains embryonic stem cells in single level with cell cycle visualization reporters to directly observe cell cycle progression. Using Fucci (fluorescent ubiquitination-based cell cycle indicator) technology and computer-assisted fluorescence microscopy we were able to visualize cell cycle progression of mouse embryonic stem cells prepared from Fucci2 knock-in mice (mES/Fucci2). Imaged mES/Fucci2 cells were plated on coverslips coated with recombinant E-cadherin-IgG Fc (E-cad-Fc). This artificial extracellular matrix effectively increases adherence of cultured cells to coverslips, which is advantageous for fluorescence imaging. mES/Fucci2 cells on the E-cad-Fc maintained the typical cell cycle of mES cells with truncated G1 phase and pluripotency. During time-lapse imaging, we were able to track these cells with dendritic-like cell morphology and many pseudopodial protrusions. By contrast, the cell cycle progression of mES/Fucci2 cells on mouse embryonic fibroblasts (MEFs) was not observable due to their compact aggregation. Cell cycle duration of mES/Fucci2 cells on the E-cad-Fc was 16 h. Thus, the unique properties of our immunocytochemical analysis have revealed that decline of pluripotency of the Fucci2 mES cells on the E-cad-Fc was coordinated with their differentiation.
Short-term effects of noisy pressure support ventilation in patients with acute hypoxemic respiratory failure
Authors: Spieth Peter M , Güldner Andreas , Huhle Robert , Beda Alessandro , Bluth Thomas , Schreiter Dierk , Ragaller Max , Gottschlich Birgit , Kiss Thomas , Jaber Samir , Pelosi Paolo , Koch Thea , Gama de Abreu Marcelo
Published: October 2013

Introduction

This study aims at comparing the very short-term effects of conventional and noisy (variable) pressure support ventilation (PSV) in mechanically ventilated patients with acute hypoxemic respiratory failure.

Methods

Thirteen mechanically ventilated patients with acute hypoxemic respiratory failure were enrolled in this monocentric, randomized crossover study. Patients were mechanically ventilated with conventional and noisy PSV, for one hour each, in random sequence. Pressure support was titrated to reach tidal volumes approximately 8 mL/kg in both modes. The level of positive end-expiratory pressure and fraction of inspired oxygen were kept unchanged in both modes. The coefficient of variation of pressure support during noisy PSV was set at 30%. Gas exchange, hemodynamics, lung functional parameters, distribution of ventilation by electrical impedance tomography, breathing patterns and patient-ventilator synchrony were analyzed.

Results

Noisy PSV was not associated with any adverse event, and was well tolerated by all patients. Gas exchange, hemodynamics, respiratory mechanics and spatial distribution of ventilation did not differ significantly between conventional and noisy PSV. Noisy PSV increased the variability of tidal volume (24.4 ± 7.8% vs. 13.7 ± 9.1%, P <0.05) and was associated with a reduced number of asynchrony events compared to conventional PSV (5 (0 to 15)/30 min vs. 10 (1 to 37)/30 min, P <0.05).

Conclusions

In the very short term, noisy PSV proved safe and feasible in patients with acute hypoxemic respiratory failure. Compared to conventional PSV, noisy PSV increased the variability of tidal volumes, and was associated with improved patient-ventilator synchrony, at comparable levels of gas exchange.

Trial registration

ClinicialTrials.gov, NCT00786292
Translocator Protein/Peripheral Benzodiazepine Receptor Is Not Required for Steroid Hormone Biosynthesis
Authors: Morohaku Kanako , Pelton Susanne H. , Daugherty Daniel J. , Butler W. Ronald , Deng Wenbin , Selvaraj Vimal
Published: October 2013

Molecular events that regulate cellular biosynthesis of steroid hormones have been a topic of intense research for more than half a century. It has been established that transport of cholesterol into the mitochondria forms the rate-limiting step in steroid hormone production. In current models, both the steroidogenic acute regulatory protein (StAR) and the translocator protein (TSPO) have been implicated to have a concerted and indispensable effort in this cholesterol transport. Deletion of StAR in mice resulted in a critical failure of steroid hormone production, but deletion of TSPO in mice was found to be embryonic lethal. As a result, the role of TSPO in cholesterol transport has been established only using pharmacologic and genetic tools in vitro. To allow us to explore in more detail the function of TSPO in cell type-specific experimental manipulations in vivo, we generated mice carrying TSPO floxed alleles (TSPOfl/fl). In this study we made conditional knockout mice (TSPOcΔ/Δ) with TSPO deletion in testicular Leydig cells by crossing with an anti-Mullerian hormone receptor type II cre/+ mouse line. Genetic ablation of TSPO in steroidogenic Leydig cells in mice did not affect testosterone production, gametogenesis, and reproduction. Expression of StAR, cytochrome P450 side chain cleavage enzyme, 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase type I, and TSPO2 in TSPOcΔ/Δ testis was unaffected. These results challenge the prevailing dogma that claims an essential role for TSPO in steroid hormone biosynthesis and force reexamination of functional interpretations made for this protein. This is the first study examining conditional TSPO gene deletion in mice. The results show that TSPO function is not essential for steroid hormone biosynthesis.
QUIRKY interacts with STRUBBELIG and PAL OF QUIRKY to regulate cell growth anisotropy during Arabidopsis gynoecium development
Authors: Trehin Christophe , Schrempp Sandra , Chauvet Aurélie , Berne-Dedieu Annick , Thierry Anne-Marie , Faure Jean-Emmanuel , Negrutiu Ioan , Morel Patrice
Published: October 2013

Organ morphogenesis largely relies on cell division and elongation, which need to be both coordinated between cells and orchestrated with cytoskeleton dynamics. However, components that bridge the biological signals and the effectors that define cell shape remain poorly described. We have addressed this issue through the functional characterisation of QUIRKY (QKY), previously isolated as being involved in the STRUBBELIG (SUB) genetic pathway that controls cell-cell communication and organ morphogenesis in Arabidopsis. QKY encodes a protein containing multiple C2 domains and transmembrane regions, and SUB encodes an atypical LRR-receptor-like kinase. We show that twisting of the gynoecium observed in qky results from the abnormal division pattern and anisotropic growth of clustered cells arranged sporadically along the gynoecium. Moreover, the cortical microtubule (CMT) network of these cells is disorganised. A cross to botero, a katanin mutant in which the normal orientation of CMTs and anisotropic cell expansion are impaired, strongly reduces silique deviation, reinforcing the hypothesis of a role for QKY in CMT-mediated cell growth anisotropy. We also show that QKY is localised at the plasma membrane and functions in a multiprotein complex that includes SUB and PAL OF QUIRKY (POQ), a previously uncharacterised PB1-domain-containing protein that localises both at the plasma membrane and in intracellular compartments. Our data indicate that QKY and its interactors play central roles linking together cell-cell communication and cellular growth.
Par3 controls neural crest migration by promoting microtubule catastrophe during contact inhibition of locomotion
Authors: Moore Rachel , Theveneau Eric , Pozzi Sara , Alexandre Paula , Richardson Joanna , Merks Anne , Parsons Maddy , Kashef Jubin , Linker Claudia , Mayor Roberto
Published: October 2013

There is growing evidence that contact inhibition of locomotion (CIL) is essential for morphogenesis and its failure is thought to be responsible for cancer invasion; however, the molecular bases of this phenomenon are poorly understood. Here we investigate the role of the polarity protein Par3 in CIL during migration of the neural crest, a highly migratory mesenchymal cell type. In epithelial cells, Par3 is localised to the cell-cell adhesion complex and is important in the definition of apicobasal polarity, but the localisation and function of Par3 in mesenchymal cells are not well characterised. We show in Xenopus and zebrafish that Par3 is localised to the cell-cell contact in neural crest cells and is essential for CIL. We demonstrate that the dynamics of microtubules are different in different parts of the cell, with an increase in microtubule catastrophe at the collision site during CIL. Par3 loss-of-function affects neural crest migration by reducing microtubule catastrophe at the site of cell-cell contact and abrogating CIL. Furthermore, Par3 promotes microtubule catastrophe by inhibiting the Rac-GEF Trio, as double inhibition of Par3 and Trio restores microtubule catastrophe at the cell contact and rescues CIL and neural crest migration. Our results demonstrate a novel role of Par3 during neural crest migration, which is likely to be conserved in other processes that involve CIL such as cancer invasion or cell dispersion.
Pax9 regulates a molecular network involving Bmp4, Fgf10, Shh signaling and the Osr2 transcription factor to control palate morphogenesis
Authors: Zhou Jing , Gao Yang , Lan Yu , Jia Shihai , Jiang Rulang
Published: October 2013

Cleft palate is one of the most common birth defects in humans. Whereas gene knockout studies in mice have shown that both the Osr2 and Pax9 transcription factors are essential regulators of palatogenesis, little is known about the molecular mechanisms involving these transcription factors in palate development. We report here that Pax9 plays a crucial role in patterning the anterior-posterior axis and outgrowth of the developing palatal shelves. We found that tissue-specific deletion of Pax9 in the palatal mesenchyme affected Shh expression in palatal epithelial cells, indicating that Pax9 plays a crucial role in the mesenchyme-epithelium interactions during palate development. We found that expression of the Bmp4, Fgf10, Msx1 and Osr2 genes is significantly downregulated in the developing palatal mesenchyme in Pax9 mutant embryos. Remarkably, restoration of Osr2 expression in the early palatal mesenchyme through a Pax9Osr2KI allele rescued posterior palate morphogenesis in the absence of Pax9 protein function. Our data indicate that Pax9 regulates a molecular network involving the Bmp4, Fgf10, Shh and Osr2 pathways to control palatal shelf patterning and morphogenesis.
Self-Assembled Dimerization of Bis(crown ether)-2,2′-bibenzimidazoles
Authors: Satake Akiharu , Tanaka Kazuo , Asakura Hiroki , Okano Masahiro , Hashimoto Tsutsumu , Matsuura You , Inaba Yusuke , Oda Tetsuhisa , Hirota Shun , Koshino Hiroyuki
Published: October 2013

Bis(crown ether)-2,2′-bibenzimidazole 1 and its 1-substituted derivatives were synthesized as new self-assembled motifs. UV–vis and 1H NMR titration experiments of 1 with potassium ions in a mixture of chloroform and methanol (1:1) were carried out. The stoichiometries and curve fitting analysis showed that a 2:2 complex of 1 with potassium ions was formed in a face-to-face fashion. 1-Monosubstituted bis(crown ether)-2,2′-bibenzimidazole 6a having a (dodecylaminocarbonyl)methyl group also gave a 2:2 complex with potassium ions. Structural analysis of the 2:2 complex of 6a with potassium ions was performed using various two-dimensional NMR techniques. Results suggested that, of eight or more possible conformational isomers, the one having the two substituent groups diagonally opposite each other was predominantly formed. Reversible association and dissociation of the 2:2 complex was observed after adding potassium ions and then removing them with an 18-crown-6-ether.
Liquefied Graphene Oxide with Excellent Amphiphilicity
Authors: Liu Xuan , Zeng Chunfang , Tang Zhenghai , Guo Baochun
Published: October 2013

A new route for liquefying graphene oxide (GO) into supramolecular ionic liquid (SIL) was proposed by the grafting of chloroacetic acid and the subsequent neutralization of carboxy groups with monofunctionalized polyetheramine (Jeffamine 2070). The rheological measurements verified its viscoelastic and liquid-like behavior. The peculiar phenomenon was mainly attributed to the formation of ionic bonds between the corona of chloroacetic acid and the canopy of Jeffamine. This type of highly viscous GO-based liquid possesses excellent amphiphilicity.
Profiting from Regulation: Evidence from the European Carbon Market
Authors: Bushnell James B , Chong Howard , Mansur Erin T
Published: October 2013

We investigate how cap-and-trade regulation affects profits. In late April 2006, the EU CO2 allowance price dropped 50 percent, equating to a €28 billion reduction in the value of aggregate annual allowances. We examine daily returns for 552 stocks from the EUROSTOXX index. Despite reductions in environmental costs, we find that stock prices fell for firms in both carbon- and electricity-intensive industries, particularly for firms selling primarily within the EU. Our results imply that investors focus on product price impacts, rather than just compliance costs and the nominal value of pollution permits. (JEL G12, G14, L94, Q53, Q54, Q58)
Depth-dependent mortality of reef corals following a severe bleaching event: implications for thermal refuges and population recovery
Authors: Bridge Tom C. L. , Hoey Andrew S , Campbell Stuart J , Muttaqin Efin , Rudi Edi , Fadli Nur , Baird Andrew H
Published: October 2013

Coral bleaching caused by rising sea temperature is a primary cause of coral reef degradation. However, bleaching patterns often show significant spatial variability, therefore identifying locations where local conditions may provide thermal refuges is a high conservation priority. Coral bleaching mortality often diminishes with increasing depth, but clear depth zonation of coral communities and putative limited overlap in species composition between deep and shallow reef habitats has led to the conclusion that deeper reef habitats will provide limited refuge from bleaching for most species. Here, we show that coral mortality following a severe bleaching event diminished sharply with depth.Bleaching-induced mortality ofAcroporawas approximately 90% at 0-2m, 60% at 3-4 m, yet at 6-8m there was negligible mortality. Importantly, at least two-thirds of the shallow-water (2-3 m)Acroporaassemblage had a depth range that straddled the transition from high to low mortality. Cold-water upwelling may have contributed to the lower mortality observed in all but the shallowest depths. Our results demonstrate that, in this instance, depth provided a refuge for individuals from a high proportion of species in thisAcropora-dominated assemblage. The persistence of deeper populations may provide a critical source of propagules to assist recovery of adjacent shallow-water reefs.
Modeling Influenza Pandemic and Planning Food Distribution
Authors: Ekici Ali , Keskinocak Pınar , Swann Julie L.
Published: October 2013

Based on the recent incidents of H5N1, H1N1, and influenza pandemics in history (1918, 1957, and 1968) experts believe that a future influenza pandemic is inevitable and likely imminent. Although the severity of influenza pandemics vary, evidence suggests that an efficient and rapid response is crucial for mitigating morbidity, mortality, and costs to society. Hence, preparing for a potential influenza pandemic is a high priority of governments at all levels (local, state, federal), nongovernmental organizations (NGOs), and companies. In a severe pandemic, when a large number of people are ill, infected persons and their families may have difficulty purchasing and preparing meals. Various government agencies and NGOs plan to provide meals to these households. In this paper, in collaboration with the American Red Cross, we study food distribution planning during an influenza pandemic. We develop a disease spread model to estimate the spread pattern of the disease geographically and over time, combine it with a facility location and resource allocation network model for food distribution, and develop heuristics to find near-optimal solutions for large instances. We run our combined disease spread and facility location model for the state of Georgia and present the estimated number of infections and the number of meals needed in each census tract for a one-year period along with a design of the supply chain network. Moreover, we investigate the impact of voluntary quarantine on the food demand and the food distribution network and show that its effects on food distribution can be significant. Our results could help decision makers prepare for a pandemic, including how to allocate limited resources and respond dynamically.
Understanding Pt–Rh Synergy in a Three-Way Catalytic Converter
Authors: Paranjpe Rucha , Suresh A. K. , Aghalayam Preeti
Published: October 2013

NO reduction to N2 is the key reaction for efficient operation of a three-way catalytic converter (TWC). It is reported that metal catalysts Pt and Rh co-exist as individual metals in a TWC to give synergistic performance. In this article, we have studied the NO + CO reaction for a 1:1 physical mixture of silica supported Pt and Rh catalysts using fixed bed experiments and microkinetic modeling. The microkinetic model [14] for the reaction on single metals Pt and Rh is simulated for the mixture case in CHEMKIN PRO®. It is observed that the mixture maintains the activity while producing less N2O (by-product of NO + CO reaction) thus enhancing N2 selectivity inspite of having only half amount of Rh. Analysis of surface coverages on individual metals in mixture shows that in the presence of Pt, CO poisoning of Rh is reduced at lower temperature leading to better overall conversion and selectivity. This has potential benefit in automotive catalysis, as it results in the formation of significantly lower amounts of N2O, an undesirable side-product and greenhouse gas; at a lower cost than if pure Pt/Rh catalysts were used.
Influence of fungal infection on the long-term water absorption and morphological behavior of bagasse fiber/polypropylene composites at different exposure times
Authors: Kord Behzad , Hosseinihashemi Seyyed Khalil , Modirzare Mehdi
Published: October 2013

In this study, the effect of fungal decay on the long-term water absorption of bagasse fiber/polypropylene composites at different exposure times was studied. For this purpose, the blend composites were prepared through the melt mixing of bagasse fiber with polypropylene at 40:60% weight ratios, with 2% coupling agent for all formulations. Then, the samples were exposed to brown-rot (Coniophora puteana) and white-rot (Trametes versicolor) fungal treatments for 8, 12 and 16 weeks with the Kolle flask method. The long-term water absorptions of samples were evaluated by immersing them in water at room temperature for several weeks, and water diffusion coefficients were also calculated by evaluating the water absorption isotherms. Also, the morphology of composites was characterized using scanning electron microscopy (SEM). The results showed that the water absorption of samples was actually much higher after both types of rotting and was significantly higher than that of control samples. Also, the water absorption of white-rotted samples was higher than that of brown-rotted and control samples for all weeks of fungal exposure times. In addition, the control sample and composite after 16 weeks of exposure to white-rot fungi exhibited the lowest and highest water diffusion coefficients, respectively. The mechanism of water absorption of samples against fungal decay at different exposure times followed the kinetics of a Fickian diffusion process. Furthermore, the SEM micrographs showed that the extent of degradation increased with increasing exposure time to fungus.