bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of mechanical properties, toughness, and barrier properties of PMMA‐EVA‐organoclay nanocomposites with and without in situ crosslinking
Authors: Wu Jyh‐Horng , Li Chia‐Hao , Leu Ming‐Tsong , Wu Yao‐Tsu
Published: December 2009

Poly methyl methacrylate (PMMA)‐ethylene vinyl acetate (EVA)‐organoclay nanocomposites were prepared with and without in situ crosslinking using tetrapropoxysilane (TPOS) as a crosslinking agent and dibutyl tin oxide (DBTO) as a catalyst. Brabender Plasticorder experimental results suggest that in situ crosslinking transforms the EVA from a liquid to a viscoelastic solid. Transmission electron micrographs analysis indicates that most of the organoclay was clustered in the crosslinked EVA phase. X‐ray diffraction and morphology indicate that the PMMA‐EVA‐organoclay nanocomposites were intercalated and incompatible. Dynamic mechanical analysis (DMA) results indicate some interaction between PMMA‐EVA‐clay nanocomposites. The in situ crosslinked of EVA and the addition of organoclay increased the modulus properties of PMMA. However, in situ crosslinking slightly reduced the barrier properties of PMMA‐EVA‐organoclay nanocomposites. Copyright © 2009 John Wiley & Sons, Ltd.
Curing kinetics, thermal, mechanical, and dielectric properties based on o‐cresol formaldehyde epoxy resin with polyhedral oligomeric (N‐aminoethyl‐γ‐amino propyl)silsesquioxane
Authors: Gao Jungang , Kong Dejuan , Zhao Hongchi , Li Shurong
Published: December 2009

The curing reaction and kinetics of o‐cresol formaldehyde epoxy resin (o‐CFER) with polyhedral oligomeric silsesquioxane of N‐aminoethyl‐γ‐amino propyl group (AEAP‐POSS) were investigated by differential scanning calorimetry (DSC). The thermal, mechanical, and dielectric properties of o‐CFER/AEAP‐POSS nanocomposites were investigated with thermogravimetric analysis (TGA), torsional braid analysis (TBA), tensile tester, impact tester, and electric analyzer, respectively. The results show that the activation energy (E) of curing reaction is 58.08 kJ/mol, and the curing reaction well followed the Šesták‐Berggren (S‐B) autocatalytic model. The glass transition temperature (Tg) increases with the increase in AEAP‐POSS content, and reaches the maximum, 107°C, when the molar ratio (Ns) of amino group to epoxy group is 0.5. The nanocomposites containing a higher percentage of AEAP‐POSS exhibited a higher thermostability. The AEAP‐POSS can effectively increase the mechanical properties of epoxy resin, and the tensile and impact strengths are 2.84 MPa and 143.25 kJ m−2, respectively, when Ns is 0.5. The dielectric constant (ε), dielectric loss factor (tan δ), volume resistivity (ρv), and surface resistivity (ρs) are 4.98, 3.11 × 10−4, 3.17 × 1012 Ω cm3, and 1.41 × 1012 Ω cm2, respectively, similarly at Ns 0.5. Copyright © 2009 John Wiley & Sons, Ltd.
Pueraria thunbergiana inhibits cisplatin‐induced damage of HEI‐OC1 auditory cells through scavenging free radicals
Authors: Yu Hyeon‐Hee , Jung Su‐Young , Shin Mee‐Kyung , Park Raekil , So Hong‐Seob , You Yong‐Ouk
Published: December 2009

The radix of Pueraria thunbergiana (P. thunbergiana) is traditionally prescribed to attenuate the clinical manifestation of inner ear dysfunction and various clinical situations including fevers, gastrointestinal disorders, skin problems, migraine headaches, lowering cholesterol, and treating chronic alcoholism in oriental medicine. In the present study, we examined the protective effect of ethanol extract of the radix of P. thunbergiana (RPT) on cisplatin‐induced damage of HEI‐OC1 auditory hair cells. When the cells were cultured in the medium containing 5–100 μg/mL of RPT, RPT showed protective effect against the cisplatin‐induced HEI‐OC1 cell damage. We also measured the effects of RPT on lipid peroxidation of cisplatin‐treated cells as well as scavenging activities against superoxide radical, hydroxyl radical, hydrogen peroxide, and DPPH radical. RPT reduced cisplatin‐induced lipid peroxidation in a dose‐dependent manner. Furthermore, RPT showed strong scavenging activity against superoxide radical, hydroxyl radical, hydrogen peroxide, and DPPH radical. These results indicate that RPT protects cisplatin‐induced HEI‐OC1 cell damage through inhibition of lipid peroxidation and scavenging activities of free radials. Copyright © 2009 John Wiley & Sons, Ltd.
The effects of salvianolic acid B from radix salvia miltiorrhizae on the oral pharmacokinetics of metoprolol and metoprolol acid in rats
Authors: Wan Ren‐Zhong , Zhou Mao‐Jin , Liu Chang‐Xiao
Published: December 2009

The present study aimed to investigate the effects of salvianolic acid B (SalB) isolated fromRadix Salvia miltiorrhizaeon the oral pharmacokinetics of metoprolol (MET) and metoprolol acid (META) in rats. The pharmacokinetic parameters of MET and META were measured after oral (15 mg/kg) administration of MET in rats in the presence and absence of SalB. Compared to the control given MET alone, with the concurrent administration of SalB (50 mg/kg), theAUCandCmaxof MET increased by 51.7% and 27.7%, and theAUCandCmaxof META decreased by 26.5% and 19.6%, respectively. With the presence of SalB, the metabolic ratio was markedly decreased by 50.8%. However, no significant changes were observed in the pharmacokinetic parameters of SalB when it was combined with MET. Copyright © 2009 John Wiley & Sons, Ltd.
Mutagenic and antimutagenic effects of hexane extract of some Astragalus species grown in the eastern Anatolia region of Turkey
Authors: Gulluce Medine , Agar Guleray , Baris Ozlem , Karadayi Mehmet , Orhan Furkan , Sahin Fikrettin
Published: December 2009

Medical plants and their various extracts have been occasionally used in the treatment of many diseases. Astragalus is one of those medical plants and it has several biological activities. In the present study, the hexane extracts of six Astragalus species, which are grown in the eastern Anatolia region of Turkey, were isolated, and their mutagenic and antimutagenic properties were investigated by using Salmonella typhimurium TA1535, TA1537 and Escherichia coli WP2uvrA tester strains at 0.05, 0.5 and 5 μg/plate concentrations. Known mutagens sodium azide (NaN3), 9‐Aminoacridine (9‐AA) and N‐Methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG) were used to determine antimutagenic properties of hexane extracts.
The results showed that all hexane extracts, investigated in the present study, can be considered genotoxically safe because they do not have mutagenic activity at the tested concentrations. But, a great many of them have antimutagenic activity against 9‐Aminoacridine known as a model intercalator agent. The inhibition rates obtained from the antimutagenicity assays ranged from 27.51% (A. macrocephalus – 0.05 μg/plate) to 54.39% (A. galegiformis – 5 μg/plate). These activities are valuable toward an extension of the employ of these drugs as new phytotherapeutic or preservative ingredients. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamics of nonlinear error growth and season‐dependent predictability of El Niño events in the Zebiak–Cane model
Authors: Yu Yanshan , Duan Wansuo , Xu Hui , Mu Mu
Published: December 2009

With the intermediate‐complexity Zebiak–Cane model, we investigate the ‘spring predictability barrier’ (SPB) problem for El Niño events by tracing the evolution of conditional nonlinear optimal perturbation (CNOP), where CNOP is superimposed on the El Niño events and acts as the initial error with the biggest negative effect on the El Niño prediction. We show that the evolution of CNOP‐type errors has obvious seasonal dependence and yields a significant SPB, with the most severe occurring in predictions made before the boreal spring in the growth phase of El Niño. The CNOP‐type errors can be classified into two types: one possessing a sea‐surface‐temperature anomaly pattern with negative anomalies in the equatorial central‐western Pacific, positive anomalies in the equatorial eastern Pacific, and a thermocline depth anomaly pattern with positive anomalies along the Equator, and another with patterns almost opposite to those of the former type. In predictions through the spring in the growth phase of El Niño, the initial error with the worst effect on the prediction tends to be the latter type of CNOP error, whereas in predictions through the spring in the decaying phase, the initial error with the biggest negative effect on the prediction is inclined to be the former type of CNOP error. Although the linear singular vector (LSV)‐type errors also have patterns similar to the CNOP‐type errors, they cover a more localized area than the CNOP‐type errors and cause a much smaller prediction error, yielding a less significant SPB. Random errors in the initial conditions are also superimposed on El Niño events to investigate the SPB. We find that, whenever the predictions start, the random errors neither exhibit an obvious season‐dependent evolution nor yield a large prediction error, and thus may not be responsible for the SPB phenomenon for El Niño events. These results suggest that the occurrence of the SPB is closely related to particular initial error patterns. The two kinds of CNOP‐type error are most likely to cause a significant SPB. They have opposite signs and, consequently, opposite growth behaviours, a result which may demonstrate two dynamical mechanisms of error growth related to SPB: in one case, the errors grow in a manner similar to El Niño; in the other, the errors develop with a tendency opposite to El Niño. The two types of CNOP error may be most likely to provide the information regarding the ‘sensitive area’ of El Niño–Southern Oscillation (ENSO) predictions. If these types of initial error exist in realistic ENSO predictions and if a target method or a data assimilation approach can filter them, the ENSO forecast skill may be improved. Copyright © 2009 Royal Meteorological Society
Evolution of transcriptional regulatory networks in yeast populations
Authors: Cavalieri Duccio
Published: December 2009

Saccharomyces cerevisiae is the most thoroughly studied eukaryote at the cellular, molecular, and genetic level. Recent boost in whole‐genome sequencing, array‐based allelic variation mapping, and genome‐wide transcriptional profiling have unprecedentedly advanced knowledge on cell biology and evolution of this organism. It is now possible to investigate how evolution shapes the functional architecture of yeast genomes and how this architecture relates to the evolution of the regulatory networks controlling the expression of genes that make up an organism. A survey of the information on genetic and whole‐genome expression variations in yeast populations shows that a significant score of gene expression variation is dependent on genotype‐by‐environment interaction. In some cases, large trans effects are the result of mutations in the promoters of key master regulator genes. Yet trans‐variation in environmental sensor proteins appears to explain the majority of the expression patterns differentiating strains in natural populations. The challenge is now to use this information to model how individual genetic polymorphisms interact in a condition‐dependent fashion to produce phenotypic change. In this study, we show how fruitful application of systems biology to the progress of science and medicine requires the use of evolution as a lens to reconstruct the hierarchical structure of regulation of biological systems. The lessons learned in yeast can be of paramount importance in advancing the application of genomics and systems biology to emerging fields including personalized medicine. Copyright © 2009 John Wiley & Sons, Inc.

This article is categorized under:

Models of Systems Properties and Processes > Cellular Models
An Observational Trial for Papillary Thyroid Microcarcinoma in Japanese Patients
Authors: Ito Yasuhiro , Miyauchi Akira , Inoue Hiroyuki , Fukushima Mitsuhiro , Kihara Minoru , Higashiyama Takuya , Tomoda Chisato , Takamura Yuuki , Kobayashi Kaoru , Miya Akihiro
Published: November 2009

Background

The recent development and spread of ultrasonography and ultrasonography‐guided fine needle aspiration biopsy (FNAB) has facilitated the detection of small papillary microcarcinomas of the thyroid measuring 1 cm or less (PMC). The marked difference in prevalence between clinical thyroid carcinoma and PMC detected on mass screening prompted us to observe PMC unless the lesion shows unfavorable features, such as location adjacent to the trachea or on the dorsal surface of the thyroid possibly invading the recurrent laryngeal nerve, clinically apparent nodal metastasis, or high‐grade malignancy on FNAB findings. In the present study we report comparison of the outcomes of 340 patients with PMC who underwent observation and the prognosis of 1,055 patients who underwent immediate surgery without observation.

Methods

Between 1993 and 2004, 340 patients underwent observation and 1,055 underwent surgical treatment without observation. These 1,395 patients were enrolled in the present study. Observation periods ranged from 18 to 187 months (average 74 months).

Results

The proportions of patients whose PMC showed enlargement by 3 mm or more were 6.4 and 15.9% on 5‐year and 10‐year follow‐up, respectively. Novel nodal metastasis was detected in 1.4% at 5 years and 3.4% at 10 years. There were no factors related to patient background or clinical features linked to either tumor enlargement or the novel appearance of nodal metastasis. After observation 109 of the 340 patients underwent surgical treatment for various reasons, and none of those patients showed carcinoma recurrence. In patients who underwent immediate surgical treatment, clinically apparent lateral node metastasis (N1b) and male gender were recognized as independent prognostic factors of disease‐free survival.

Conclusions

Papillary microcarcinomas that are not associated with unfavorable features can be candidates for observation regardless of patient background and clinical features. If there are subsequent signs of progression, such as tumor enlargement and novel nodal metastasis, it would not be too late to perform surgical treatment. Even though the primary tumor is small, careful surgical treatment including therapeutic modified neck dissection is necessary for N1b PMC patients.
Reduction of commercial aircraft noise emission around airports. A new environmental challenge
Authors: Khardi Salah
Published: December 2009

Noise abatement procedures (NAPs) are considered as a necessary measure for a balanced approach of noise control around airports. Their correct implementation depends upon many factors, which vary in operation and influence the efficiency of the NAPs. Any system, which defines the correct features of the NAPs for particular aircraft in specific conditions, would be useful for noise control. Thus, implementation of noise level monitoring systems, currently used around airports, gives a noise map in residential areas but cannot identify source frequencies and their impact on the environment. Consequently, this paper has been produced particularly to characterize the frequential aspect of aircraft noise emission. Its main objective is the analysis of the dominant frequencies emitted during approaches to the Lyon Saint-Exupéry International Airport (France) having a negative impact on the population living around this airport. Thus, the results obtained make it possible to show, through an empirical model of aircraft noise, the effectiveness of this experimental work.
Change in Hemoglobin Levels due to Anesthesia in Mice: An Important Confounder in Studies on Hematopoietic Drugs
Authors: Gothelf Anita , Hojman Pernille , Gehl Julie
Published: December 2009

Analgesic and anesthetic drugs may have an impact on the results achieved from animal experiments. In the study presented here, we try to enlighten whether anesthesia with fentanyl/fluniasone and midazolam (Hypnorm and Dormicum) has an influence on measurements of hemoglobin in mice. In a cross-over study, we have compared hemoglobin levels in two groups of mice: anesthetized versus non-anesthetized and found significant decrease in hemoglobin levels in the anesthetized group (p < 0.05) unrelated to which group received the anesthesia. The mean hemoglobin levels after intraperitoneal administration of Hypnorm and Dormicum was 8.7 mmol/L compared to mean hemoglobin 9.9 mmol/L before anesthesia (p < 0.001), and the decrease lasted for more than 30 min. These results show that anesthesia can be an important confounder in studies involving measurements of hemoglobin, and this should be taken into account when planning studies and analyzing data.
Is physical functioning influenced by activity‐related pain prediction and fear of movement in patients with subacute low back pain?
Authors: Huijnen Ivan P.J. , Verbunt Jeanine A. , Peters Madelon L. , Seelen Henk A.M.
Published: November 2009

In patients with low back pain (LBP), physical functioning may be negatively influenced by both expectations on pain and pain‐related fear. It is unclear whether these factors influence both physical functioning in the laboratory as well as in daily life. The aim of this study was to test if a combination of persistent overprediction of pain and fear of movement predicts lab‐based performance and whether these factors are relevant for predicting daily‐life functioning.

One hundred and twenty four patients with subacute LBP performed a laboratory‐based performance test twice. Maximum voluntary contraction, pre‐test pain expectations, perceived pain during testing and fear of movement were measured. Patients were classified as correct or incorrect predictors, based on differences between expected and perceived pain on the second attempt. Next, physical activity in daily life was measured with an accelerometer.

In explaining physical functioning in the laboratory and in daily life an interaction effect between fear and pain prediction was observed. In overpredictors, fear was negatively associated with lab‐based performance (β = −0.48, p < 0.01), and positively associated with daily‐life functioning (β = 0.50, p < 0.05). No significant association between fear and performance or daily‐life functioning were found in correct predictors.

In contrast to correct predictors, in overpredictors lab‐based performance and daily‐life functioning was additionally explained by fear of movement. Thus it appears that fear of movement is only predictive of performance in patients with LBP who simultaneously overpredict the consequences of movements in terms of painfulness.
Behaviour of an air-assisted jet submitted to a transverse high-frequency acoustic field
Authors: BAILLOT F. , BLAISOT J.-B. , BOISDRON G. , DUMOUCHEL C.
Published: December 2009

Acoustic instabilities with frequencies roughly higher than 1 kHz remain among the most harmful instabilities, able to drastically affect the operation of engines and even leading to the destruction of the combustion chamber. By coupling with resonant transverse modes of the chamber, these pressure fluctuations can lead to a large increase of heat transfer fluctuations, as soon as fluctuations are in phase. To control engine stability, the mechanisms leading to the modulation of the local instantaneous rate of heat release must be understood. The commonly developed global approaches cannot identify the dominant mechanism(s) through which the acoustic oscillation modulates the local instantaneous rate of heat release. Local approaches are being developed based on processes that could be affected by acoustic perturbations. Liquid atomization is one of these processes. In the present paper, the effect of transverse acoustic perturbations on a coaxial air-assisted jet is studied experimentally. Here, five breakup regimes have been identified according to the flow conditions, in the absence of acoustics. The liquid jet is placed either at a pressure anti-node or at a velocity anti-node of an acoustic field. Acoustic levels up to 165 dB are produced. At a pressure anti-node, breakup of the liquid jet is affected by acoustics only if it is assisted by the coaxial gas flow. Effects on the liquid core are mainly due to the unsteady modulation of the annular gas flow induced by the acoustic waves when the mean dynamic pressure of the gas flow is lower than the acoustic pressure amplitude. At a velocity anti-node, local nonlinear radiation pressure effects lead to the flattening of the jet into a liquid sheet. A new criterion, based on an acoustic radiation Bond number, is proposed to predict jet flattening. Once the sheet is formed, it is rapidly atomized by three main phenomena: intrinsic sheet instabilities, Faraday instability and membrane breakup. Globally, this process promotes atomization. The spray is also spatially organized under these conditions: large liquid clusters and droplets with a low ejection velocity can be brought back to the velocity anti-node plane, under the action of the resulting radiation force. These results suggest that in rocket engines, because of the large number of injectors, a spatial redistribution of the spray could occur and lead to inhomogeneous combustion producing high-frequency combustion instabilities.
Experimental investigation into localized instabilities of mixed Rayleigh–Bénard–Poiseuille convection
Authors: GRANDJEAN EMERIC , MONKEWITZ PETER A.
Published: December 2009

The stability of the Rayleigh–Bénard–Poiseuille flow in a channel with large transverse aspect ratio (ratio of width to vertical channel height) is studied experimentally. The onset of thermal convection in the form of ‘transverse rolls’ (rolls with axes perpendicular to the Poiseuille flow direction) is determined in the Reynolds–Rayleigh number plane for two different working fluids: water and mineral oil with Prandtl numbers of approximately 6.5 and 450, respectively. By analysing experimental realizations of the system impulse response it is demonstrated that the observed onset of transverse rolls corresponds to their transition from convective to absolute instability. Finally, the system response to localized patches of supercriticality (in practice local ‘hot spots’) is observed and compared with analytical and numerical results of Martinand, Carrière & Monkewitz (J. Fluid Mech., vol. 502, 2004, p. 175 and vol. 551, 2006, p. 275). The experimentally observed two-dimensional saturated global modes associated with these patches appear to be of the ‘steep’ variety, analogous to the one-dimensional steep nonlinear modes of Pier, Huerre & Chomaz (PhysicaD, vol. 148, 2001, p. 49).
A coupled time-reversal/complex differentiation method for aeroacoustic sensitivity analysis: towards a source detection procedure
Authors: DENEUVE ARIANE , DRUAULT PHILIPPE , MARCHIANO RÉGIS , SAGAUT PIERRE
Published: December 2009

Defining and identifying the aeroacoustic sources in a turbulent flow is a great challenge especially for noise control strategy. The purpose of the present study consists in proposing a new methodology to localize regions associated with sound generation. These regions are associated, in the present work, with those of high sensitivity of the acoustic field, using the heuristic argument that modifying the flow in these regions would lead to a very significant change in the radiated noise. The proposed method relies on the efficient coupling between the time-reversal theory applied to the Euler equations and the complex differentiation method to compute the sensitivity variable. To the knowledge of the authors, this is the first time that the time-reversal technique is applied to vectorial hydrodynamic equations, in place of the classical scalar wave equation. Subsequently, regions associated with sound generation are related to spatiotemporal events which exhibit the maximum of sensitivity to acoustical disturbances measured in far field. The proposed methodology is then successively tested on three cases for which the nature of the source is different: injection of mass, vibrating surfaces and flow instabilities arising in a plane mixing layer flow. For each test case, the two-dimensional Euler equations are solved using a numerical solver based on a pseudo-characteristics formulation. During these computations flow, variables are stored only at the computational boundaries. These variables are time reversed and relevant information concerning the acoustical disturbances is tagged using complex differentiation in order to lead the sensitivity analysis. The same numerical solver is used to access the evolution of the time-reversed variables. In each test case, the proposed methodology allows to localize successfully zones associated with noise generation.
The Claim of John 7.15 and the Memory of Jesus' Literacy
Authors: Keith Chris
Published: December 2009

This article argues that John 7.15 claims neither literacy nor illiteracy for Jesus, but rather that Jesus was able to confuse his opponents with regards to his scribal literacy. According to the Johannine narrator, Jesus' opponents assumed he did not ‘know letters’, but also acknowledged that he taught as if he did. This article also suggests that the claim of John 7.15 is historically plausible in light of first-century Christianity's corporate memory(ies) of Jesus' literacy.
Temple Concerns and High-Priestly Prosecutions from Peter to James: Between Narrative and History
Authors: Regev Eyal
Published: December 2009

This article demonstrates that according to the Acts of the Apostles, the major charges brought against Peter, Stephen, and Paul—as well as, in later Christian texts, against James—are violations of the Temple's sacredness, both by means of statements about and actions within it. On the narrative level, in their portrayal of the conflicts and trials of these early Christian leaders, the ancient Christian sources argued that because the early Christian community in Jerusalem sought to partake in the Temple worship in its own way, Jesus' followers were falsely accused of violating the Temple's sacredness. On the historical level, it may be concluded that these events were authentic, and that they were affected by two factors: (a) The assumption, on the part of the Jewish community, that Jesus represented an anti-Temple stance. This assumption was based on Jesus' ‘cleansing’ action at the Temple, and the saying attributed to him regarding the destruction of the Temple and the erection of a new one ‘not made with [human] hands’. As such, Jesus' followers were viewed as posing a threat to the Temple as well. (b) The meticulous approach to Temple rituals held by the Sadducean high priests in charge of the prosecutions. According to their approach, any deviance from the proscribed procedure desecrated the sacrificial cult and was to be avoided at any cost.
Evaluation of Clostridium difficile in dogs and the household environment
Authors: WEESE J. S. , FINLEY R. , REID-SMITH R. R. , JANECKO N. , ROUSSEAU J.
Published: December 2009

Clostridium difficile may be an emerging community-associated pathogen but little is known about its sources of exposure. This study evaluated C. difficile contamination in households and colonization of pets. C. difficile was isolated from 44/836 (5·3%) sites in 26/84 (31%) households. Ribotype 027 was the most common (25%) environmental strain. C. difficile was isolated from 14/139 (10%) dogs. Living with an immunocompromised individual was associated with C. difficile colonization in dogs. All toxigenic strains identified in pets have been isolated from humans in Ontario. C. difficile was isolated concurrently from dogs and the environment in four households, but in all cases canine and environmental ribotypes were different. C. difficile was relatively common in households, suggesting that exposure to this pathogen may be a regular event. There was no evidence that dogs are a significant source of household C. difficile contamination.
Strong Alpine glacier melt in the 1940s due to enhanced solar radiation
Authors: Huss M. , Funk M. , Ohmura A.
Published: December 2009

A 94‐year time series of annual glacier melt at four high elevation sites in the European Alps is used to investigate the effect of global dimming and brightening of solar radiation on glacier mass balance. Snow and ice melt was stronger in the 1940s than in recent years, in spite of significantly higher air temperatures in the present decade. An inner Alpine radiation record shows that in the 1940s global shortwave radiation over the summer months was 8% above the long‐term average and significantly higher than today, favoring rapid glacier mass loss. Dimming of solar radiation from the 1950s until the 1980s is in line with reduced melt rates and advancing glaciers.
High resolution seismic imaging of the ocean structure using a small volume airgun source array in the Gulf of Cadiz
Authors: Geli L. , Cosquer E. , Hobbs R. W. , Klaeschen D. , Papenberg C. , Thomas Y. , Menesguen C. , Hua B. L.
Published: December 2009

A small volume (117 cu‐inch) seismic source producing signal predominantly in the 150–200 Hz frequency window was used during the GO calibration experiment in the Gulf of Cadiz (April–May 2007). The data show the small scale (<10 m in the z direction) internal structure of the ocean. High‐resolution images display seismic reflectors that often appear as distinct, horizontal, short (∼a few hundred meters to a few km long) segments, lying at different depths, while low‐resolution (∼20 to 30 Hz) display long, horizontal reflectors (∼a few tens of km), sometimes linked by short, apparently “dipping” segments. The present data suggest that this apparent dipping effect is due to the insufficient separation power (∼λ/4) of the low resolution data. Improving high resolution acquisition systems hence appears to be a critical challenge to understand the seismic response of the ocean.
Interannual CO2 exchange of a sparse Mediterranean shrubland on a carbonaceous substrate
Authors: Serrano‐Ortiz P. , Domingo F. , Cazorla A. , Were A. , Cuezva S. , Villagarcía L. , Alados‐Arboledas L. , Kowalski A. S.
Published: December 2009

This study presents the interannual CO2 exchange of a semiarid shrubland overlying a carbonaceous substrate where abiotic processes may interact with biological processes in the ecosystem carbon cycle. Estimated by the eddy covariance technique and two different gap‐filling models (RBF neural network and MDS “Marginal Distribution Sampling”), the mean annual net ecosystem exchange (NEE) of CO2 varied from −63 to 29 g C m−2, averaging −2 ± 23 g C m−2 from May 2004 to December 2007. In addition, CO2 exchange was divided into periods likely dominated by clear signals of biological activity (high daytime uptake, low Bowen ratio) and periods of apparent plant senescence (dry conditions) to better understand the relative contributions of “biological versus abiotic processes” to the annual NEE and the interannual variability of these processes. During biological periods, CO2 exchange appears to be related to changes in the ecosystem leaf area index, whereas abiotic fluxes are most closely related to evapotranspiration. The timing of rainfall events seems to be a main determinant of both activation and duration of biological processes. During apparent abiotic periods, CO2 exchange is characterized by daytime emissions averaging 1.5 μmol m−2 s−1, whereas biological periods are characterized by daytime CO2 uptake with mean values of around 1.4 μmol m−2 s−1. As a preliminary result, the abiotic period characterized from 19% of 2004 to 45% of 2007 with a mean duration of approximately 2 months. However, future research is needed in order to achieve a more reliable division between determinant processes involved in CO2 exchange over carbonaceous substrates.
Features of the transport of quasi-one-dimensional surface electrons in dense gaseous helium
Authors: Smorodin A. V. , Nikolaenko V. A. , Sokolov S. S.
Published: December 2009

The results of an experimental investigation of the mobility of surface electrons localized in quasi-two-dimensional conducting channels in liquid helium on a profiled substrate are presented. The electron mobility is measured in a temperature region corresponding to scattering of particles on helium atoms in the vapor phase. It is shown that with increasing temperature the mobility decreases monotonically in proportion to the change in helium vapor density, then suffers a sharp drop that the authors attribute to the possible formation of a surface anion—electron polaron formation in the dense helium vapor. The results are in agreement with the results on the mobility of two-dimensional and three-dimensional electron systems in helium vapor.
Inherent spin transfer torque driven switching current fluctuations in magnetic element with in-plane magnetization and comparison to perpendicular design
Authors: Zhu Xiaochun , Kang Seung H.
Published: December 2009

This paper presents a systematic micromagnetic modeling study on switching current fluctuations in both in-plane and perpendicular spin-transfer-torque (STT) magnetoresistive random access memory devices. For the magnetic tunnel junction (MTJ) with in-plane magnetization, high-order spin wave modes are excited during a STT-driven switching, which leads to an inherently broad switching current distribution. If the MTJ size is not sufficiently small, a stable vortex can be formed over a wide range of current amplitudes. In contrast, the excitation of such high-order spin waves is absent in STT switching of MTJs with perpendicular magnetic anisotropy. Consequently, the fluctuation in switching current amplitude or pulse duration is significantly smaller in comparison.
Thermomigration-induced magnetic degradation of current perpendicular to the plane giant magnetoresistance spin-valve read sensors operating at high current density
Authors: Zeng Ding Gui , Chung Kyung-Won , Bae Seongtae
Published: December 2009

The theoretically analyzed physical mechanism of thermomigration (TM)-induced magnetic degradation that occurred in the current perpendicular to the plane (CPP) Ir20Mn80 exchange biased giant magnetoresistance spin-valve (EBGMR SV) read sensors is presented. The device size was changed from 60×60 to 140×140 nm2 at the fixed aspect ratio of 1(L):1(W), and the operating current density was varied from J=1×108 A/cm2 to J=5×108 A/cm2 in a current control mode. It was numerically confirmed that the Mn atomic interdiffusion through the Ir20Mn80/Co80Fe20 interface due to the thermally induced mass transport and the “Villari magnetic reversal” of the CoFe pinned layer due to the thermally induced stress are mainly responsible for the serious degradation of exchange bias and magnetoresistance. Furthermore, the TM-induced magnetic degradation of CPP EBGMR SV read sensors was found to become severe by increasing the operating current density. However, interestingly, this undesirable magnetic degradation was dramatically diminished by reducing the read sensors below 100(L)×100(W) nm2.
Diffusion approximation of stochastic master equations with jumps
Authors: Pellegrini C. , Petruccione F.
Published: December 2009

In the presence of quantum measurements with direct photon detection, the evolution of open quantum systems is usually described by stochastic master equations with jumps. Heuristically, diffusion models can be obtained from these equations as an approximation. A condition for a general diffusion approximation for jump master equations is presented. This approximation is rigorously proved by using techniques for Markov processes, which are based on the convergence of Markov generators and martingale problems. This result is illustrated by rigorously obtaining the diffusion approximation for homodyne and heterodyne detection.
Microwave dielectric properties of BaTiO3 and Ba0.5Sr0.5TiO3 thin films on (001) MgO
Authors: Alldredge L. M. B. , Chang Wontae , Kirchoefer Steven W. , Pond Jeffrey M.
Published: December 2009

The microwave properties of BaTiO3 and Ba0.5Sr0.5TiO3 films were characterized as a function of in-plane film strain, crystallographic direction, film distortion, and dc bias. The strain dependence of BaTiO3 and Ba0.5Sr0.5TiO3 films showed an opposite pattern at room temperature, going from compression to tension, or vice versa. At zero bias, the dielectric constant and dielectric loss showed little dependence on direction ([100] and [110]). However, the tunability was consistently smaller along the [110] direction than along [100]. These observations agreed well with our previous work on how polarizations (both ionic and spontaneous) form and contribute to the nonlinear dielectric behavior.
Structure, exchange stiffness, and magnetic anisotropy of Co2MnAlxSi1−x Heusler compounds
Authors: Kubota Takahide , Hamrle Jaroslav , Sakuraba Yuya , Gaier Oksana , Oogane Mikihiko , Sakuma Akimasa , Hillebrands Burkard , Takanashi Koki , Ando Yasuo
Published: December 2009

We have investigated the exchange constant A (exchange stiffness D) and the magnetic anisotropy of Co2MnAlxSi1−x (CMAS) Heusler compounds as a function of the film composition. In case of Co2MnSi, A was found to be 23.5 pJ/m (D=5.86 meV nm2). Furthermore, A decreased with an increase in the Al content x. In the case of Co2MnAl, it was found to be 4.8 pJ/m (D=1.90 meV nm2). Finally, the cubic anisotropy constant K1 of CMAS films was found to be small (below 10 kJ/m3) and did not exhibit simple dependence on x.
Dynamics of entrained air bubbles inside a piezodriven inkjet printhead
Authors: Lee Sang Joon , Kwon Dae Hee , Choi Yong Seok
Published: December 2009

Entrained air bubbles inside a piezoelectric inkjet printhead cause a malfunction in the droplet formation and deteriorate the reliability of inkjet printing. The dynamic motion of the entrained air bubbles is investigated optically by utilizing a high-speed imaging system. Air bubbles, ingested through the inkjet nozzle, are surrounded by a pulsating pressure field inside the inkjet printhead. The bubbles oscillate and move along the inner wall of the printhead as they are subjected to the Bjerknes force. As the bubbles attract each other, they continuously coalesce and grow due to rectified diffusion until they reach the equilibrium condition.
Effect of hydration layer and surface wettability in enhancing thermal conductivity of nanofluids
Authors: Sachdeva Parveen , Kumar Ranganathan
Published: December 2009

In a molecular dynamics study of water based nanofluids, we show that a hydration layer is formed at the particle-fluid interface, where the attraction or cohesive potential between the liquid molecules is dominant. In the hydration layer, the collision mode rather than the kinetic or potential mode is primarily responsible for the enhancement of thermal transport properties in nanofluids, as it results in more interactions. The thermal conductivity for a wetting particle is found to be higher than for a neutral or a nonwetting particle.
Phylogenetic analysis and functional characterisation of strictosidine synthase-like genes in Arabidopsis thaliana
Authors: Kibble Natalie A. J. , Sohani M. Mehdi , Shirley Neil , Byrt Caitlin , Roessner Ute , Bacic Antony , Schmidt Otto , Schultz Carolyn J.
Published: December 2009

Monoterpenoid indole alkaloids (MIA) are a diverse class of secondary metabolites important for plant protection and are drugs for treating human diseases. Arabidopsis thaliana (L.) is not known to produce MIAs, yet its genome has 15 genes with similarity to the periwinkle (Catharanthus roseus (L.) G. Don) strictosidine synthase (STR) gene. Phylogenetic analysis of strictosidine synthase-like (SSL) proteins reveals four well supported classes of SSLs in Arabidopsis. To determine if Arabidopsis produces active strictosidine synthase, Arabidopsis protein extracts were assayed for enzymatic activity and cDNAs were expressed in Escherichia coli. Arabidopsis protein extracts from leaves and hairy roots do not make strictosidine at levels comparable to C. roseus, but they metabolise one substrate, secologanin, a precursor of strictosidine in other plant species, and produce an ‘unknown’ compound proposed to be a dimer of secologanic acid. Recombinant Arabidopsis proteins expressed in E. coli were not active STRs. Quantitative PCR analysis was performed on class A Ssls and showed they are upregulated by salt, ultraviolet light and salicylic acid treatment. RNAi mutants of Arabidopsis with reduced expression of all four class A Ssls, suggest that class A SSL proteins can modify secologanin. Gene expression and metabolomics data suggests that class A Ssl genes may have a role in plant protection.
Enabling tools for engineering collagenous tissues integrating bioreactors, intravital imaging, and biomechanical modeling
Authors: Niklason Laura E. , Yeh Alvin T. , Calle Elizabeth A. , Bai Yuqiang , Valentín Arturo , Humphrey Jay D.
Published: December 2009

Many investigators have engineered diverse connective tissues having good mechanical properties, yet few tools enable a global understanding of the associated formation of collagen fibers, the primary determinant of connective tissue stiffness. Toward this end, we developed a biomechanical model for collagenous tissues grown on polymer scaffolds that accounts for the kinetics of polymer degradation as well as the synthesis and degradation of multiple families of collagen fibers in response to cyclic strains imparted in a bioreactor. The model predicted well both overall thickness and stress-stretch relationships for tubular engineered vessels cultured for 8 weeks, and suggested that a steady state had not yet been reached. To facilitate future refinements of the model, we also developed bioreactors that enable intravital nonlinear optical microscopic imaging. Using these tools, we found that collagen fiber alignment was driven strongly by nondegraded polymer fibers at early times during culture, with subsequent mechano-stimulated dispersal of fiber orientations as polymer fibers degraded. In summary, mathematical models of growth and remodeling of engineered tissues cultured on polymeric scaffolds can predict evolving tissue morphology and mechanics after long periods of culture, and related empirical observations promise to further our understanding of collagen matrix development in vitro.
Shh signaling regulates adrenocortical development and identifies progenitors of steroidogenic lineages
Authors: King Peter , Paul Alex , Laufer Ed
Published: December 2009

The adrenal cortex is a critical steroidogenic endocrine tissue, generated at least in part from the coelomic epithelium of the urogenital ridge. Neither the intercellular signals that regulate cortical development and maintenance nor the lineage relationships within the adrenal are well defined. We have explored adrenal
Shh
activity and found that
Shh
is expressed in relatively undifferentiated steroidogenic cells, which signal to the overlying capsule and subjacent nonsteroidogenic mesenchyme cells that we also find are progenitors of steroidogenic lineages.
Shh
-expressing cells also generate all steroidogenic cell types, but not nonsteroidogenic ones.
Shh
mutant adrenals have a thin capsule and small cortex. Our findings both support a novel dual lineage, Shh-independent and Shh-dependent, model of adrenocortical development, and identify distinct populations of adrenocortical progenitor and candidate stem cells.
Increased Awareness and Self-Challenge of Alcohol Expectancies
Authors: Jones Lisa Madsen , Silvia Loretta Young , Richman Charles L.
Published: December 2009

Alcohol expectancies have been reported to influence both decisions to drink and the behavioral effects of alcohol and may play a role in both the prevention and the treatment of problem drinking. Prior studies have indicated that alcohol expectancies may be changed by challenging the expectancy with opposing information. This study investigated the effect of increasing awareness of alcohol expectancies, providing relevant information, and the additional impact of an intervention which encouraged self-challenging of the expectancies. Subjects were 90 college students classified as heavy, moderate, and light drinkers and were assigned to one of three conditions: (a) Expectancy Challenge (EC), (b) Expectancy Challenge with Self-Challenge or Inoculation (ECI), and (c) No-Treatment Control group. All groups participated in two intervention sessions. The ECI subjects significantly decreased their drinking over time. When examining reported drinking, the three different groups were not found to change significantly at a different rate. However, there was a significant trend, with the ECI subjects reducing their drinking the most, followed by the EC subjects, and next the Control subjects, who actually increased their drinking.
Substance Abuse in Freshmen Medical Students over Time
Authors: Sheridan David P. , Johnson N. Peter , Michels Philip J. , Marion Lucy N. , Fuller Sara G.
Published: December 2009

This study assessed the extent of alcohol use among six classes of freshman medical students over an 8-year period to provide actuarial feedback about drinking patterns to these students. A total of 278 freshman medical students was anonymously surveyed in class using the Michigan Alcoholism Screening Test (MAST). Students were given subsequent group feedback about these data with ample time for discussion. Signs of clinical detection and community resources were highlighted. Of all students 11.7% were nondrinkers, 51% were nonproblematic drinkers, 7% were borderline, 23% were 80% likely to be alcoholic, and 7% were 100% likely to be alcoholic based on the MAST score. No time trends were evident in substance use patterns. The 13-item Short MAST (SMAST) compared to the MAST had a sensitivity of 52% and a specificity of 98%. The need for better education, detection, and intervention regarding alcohol abuse among medical students was evident. Fortunately, no time trends are evident in this school's freshmen classes in contrast to national trends in college students. Teaching about problem drinking based on the administration of the MAST and from drinking norms of the class appears to increase awareness, relevance, and concern about alcohol abuse among freshmen medical students.
Prevalence of Substance Abuse and Smoking in a University Family Practice Setting
Authors: Mar David , Johnson Jay , Pistorello Jacqueline , Rigmaiden Richard , Veach Tracy L.
Published: December 2009

This study examined the prevalence and use patterns of alcohol, nicotine, and other drugs in a university ambulatory clinic. A total of 149 patients sampled during a 3-month period was asked to fill out a self-report questionnaire regarding substance use. The questionnaire included the CAGE, the AUDIT, and the T-ACE instruments. Subjects had a mean age of 35 years, were 84% Caucasian, 60% unemployed, and 80% female. Based on CAGE and T-ACE scores, 13 and 25% of the subjects would be screened for possible alcoholism, respectively. The AUDIT revealed a prevalence rate of between 15 and 31% for early problematic drinking. Forty-six percent of the sample reported current use of nicotine. There is a definite overlap between nicotine and other substance use, with smokers representing 60 and 61% of those positively screened by the CAGE and the AUDIT, respectively. Other drug use was highest for marijuana (8.7%), followed by cocaine (4.7%). These prevalence rates validate the need to provide substance abuse training for staff in family practice settings. Primary care physicians may affect both licit and illicit drug use by screening and intervening with gateway drug use such as tobacco and alcohol.