bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 1,3‐ and 1,2‐Diphosphatidylglycerol
Authors: Ahmad Moghis U. , Krishna U. Murali , Ali Shoukath M. , Choudhury Sreeti , Ahmad Imran
Published: February 2007

A novel phosphonium salt methodology was utilized for the first time to synthesize 1,3‐, and 1,2‐diphosphatidylglycerol. Optically active 1,2‐di‐O‐acyl‐sn‐glyceryl phosphate was coupled with unprotected glycerol in the presence of pyridiniumbromide perbromide and triethylamine to yield, after final removal of phosphate protecting group, the title compounds. The 1,2‐diphosphatidylglycerol (1,2‐isomer of cardiolipin) may be a member of a new class of phospholipids for industrial applications similar to other phosphocholines.
Differential trafficking of carboxyl isoforms of Ca2+‐gated (Slo1) potassium channels
Authors: Ma Donghui , Nakata Takahiro , Zhang Guangping , Hoshi Toshinori , Li Min , Shikano Sojin
Published: February 2007

The pore‐forming subunit of the large‐conductance Ca2+‐dependent K+ (Slo1) channel is encoded by one gene. However, the functional properties of Slo1 channels are diverse in part because of their numerous regulatory mechanisms including posttranslational modification and alternative splicing. In particular, multiple splice variants of the pore‐forming subunit have been reported but their significance is only beginning to be elucidated. Here we examined the cell biological properties of the three common C‐terminal isoforms that differ in the last 8 (Slo1_ERL and Slo1_VYR) or 61 residues (Slo1_DEC). We found that Slo1_DEC, the longest isoform, shows dramatically reduced surface expression compared to that of Slo1_ERL or Slo1_VYR. Immunocytochemistry revealed that a large fraction of Slo1_DEC remains localized in endoplasmic reticulum (ER). Using a GST fusion protein containing the Slo1_DEC‐specific sequence, affinity purification was carried out to isolate interacting proteins. The identified proteins include protein phosphatase 2A (PP2A‐A), actin, and tubulin. The PP2A‐A interaction is specific to Slo1_DEC and causes a significant reduction of phosphorylation in Slo1_DEC but not Slo1_ERL or Slo1_VYR. The results together support the notion that Slo1_DEC nucleates isoform‐specific protein complexes and possesses a cis element(s) for regulating trafficking of the Slo1 channels.
Carnosine and its constituents inhibit glycation of low‐density lipoproteins that promotes foam cell formation in vitro
Authors: Rashid Imran , van Reyk David M. , Davies Michael J.
Published: February 2007

Glycation of low‐density lipoprotein (LDL) by reactive aldehydes, such as glycolaldehyde, can result in the cellular accumulation of cholesterol in macrophages. In this study, it is shown that carnosine, or its constituent amino acids β‐alanine andl‐histidine, can inhibit the modification of LDL by glycolaldehyde when present at equimolar concentrations to the modifying agent. This protective effect was accompanied by inhibition of cholesterol and cholesteryl ester accumulation in human monocyte‐derived macrophages incubated with the glycated LDL. Thus, carnosine and its constituent amino acids may have therapeutic potential in preventing diabetes‐induced atherosclerosis.
CONGENITAL UNILATERAL UPPER LIMB MUSCULAR HYPERTROPHY ASSOCIATED WITH CONTRACTURE OF AN EXTRINSIC EXTENSOR TENDON
Authors: IMAI S. , ISOYA E. , KUBO M. , KODAMA N. , MATSUSUE Y.
Published: February 2007

We report a case of congenital unilateral upper limb muscular hypertrophy which presented with loss of extensor tendon excursion of a single digit in late adolescence. The reason for the problem arising is not clear and is not clearly explained by the underlying congenital pathology.
Embattled executives: Prime ministerial weakness in East Central Europe
Authors: Baylis Thomas A.
Published: February 2007

In a period in which ‘‘strong’’ and even ‘‘presidential’’ prime ministers have arguably become more the rule than the exception in the major states of Western Europe, most prime ministers in the new democracies of East Central Europe appear to have been relatively weak figures. This article investigates the reasons for that relative weakness in the ten East Central European countries, which together have had 87 prime ministers in the 16 years since the fall of Communism. It evaluates several possible explanations: party system weakness, the institutional structure, elite recruitment patterns, and policy constraints. It then seeks to explain several notable exceptions to the prime ministerial weakness rule.
A dinoflagellate cyst record of Holocene climate and hydrological changes along the southeastern Swedish Baltic coast
Authors: Yu Shi-Yong , Berglund Björn E.
Published: February 2007

A high-resolution, well-dated dinoflagellate cyst record from a lagoon of the southeastern Swedish Baltic Sea reveals climate and hydrological changes during the Holocene. Marine dinoflagellate cysts occurred initially at about 8600 cal yr BP, indicating the onset of the Littorina transgression in the southeastern Swedish lowland associated with global sea level rise, and thus the opening of the Danish straits. Both the species diversity and the total accumulation rates of dinoflagellate cysts continued to increase by 7000 cal yr BP and then decreased progressively. This pattern reveals the first-order change in local sea level as a function of ice-volume-equivalent sea level rise versus isostatic land uplift. Superimposed upon this local sea level trend, well-defined fluctuations of the total accumulation rates of dinoflagellate cysts occurred on quasi-1000- and 500-yr frequency bands particularly between 7500 and 4000 cal yr BP, when the connection between the Baltic basin and the North Atlantic was broader. A close correlation of the total accumulation rates of dinoflagellate cysts with GISP2 ice core sea-salt ions suggests that fluctuations of Baltic surface conditions during the middle Holocene might have been regulated by quasi-periodic variations of the prevailing southwesterly winds, most likely through a system similar to the dipole oscillation of the modern North Atlantic atmosphere.
Intellectual conformism depends on institutional incentives, not on socialized culture
Authors: Bennich-Björkman Li
Published: February 2007

The study by Ceci et al. shows that academic behavior associated with the core principles of intellectual freedom is more shaped by institutional incentives than by organizational culture. From an organizational theoretical point of view, this is quite an unexpected finding, not least because we do believe universities to be fairly strong and explicit cultures that should be successful in socialization.
Scientific psychology and tenure
Authors: Clark James M.
Published: February 2007

Ceci et al. draw conclusions that are inaccurate, analyze and report results inappropriately, fail to translate their scale into policy-relevant terms, and draw overly strong conclusions from their single study. They also attribute all the ills of academic appointments to tenure, and ignore problems with other aspects of the system. Their conclusion that tenure is not supported is at best premature.
American ambivalence toward academic freedom
Authors: Fuller Steve
Published: February 2007

Why are U.S. academics, even after tenure and promotion, so timid in their exercise of academic freedom? Part of the problem is institutional – academics are subject to a long probationary period under tight collegial control – but part of the problem is ideological. A hybrid of seventeenth-century British and nineteenth-century German ideals, U.S. academia – and the nation more generally – remains ambivalent toward the value of academic freedom, ultimately inhibiting an unequivocal endorsement.
Tenure and the political autonomy of faculty inquiry
Authors: Jacobson Anne Jaap
Published: February 2007

This commentary discusses several problems with the target article by Ceci et al. First, the results admit of an alternative interpretation that undercuts the conclusion drawn. In addition, at a number of points, the research should be supplemented by examining situations in which there is no tenure-granting policy. Finally, 60% of the questions are concerned with whistle-blowing, but the issues involved in such cases make them much less relevant to the assessment of tenure than the authors suppose.
Put tenure in today's social context
Authors: Wettersten John
Published: February 2007

Tenure should not be judged on its ability to promote whistle-blowing. Because the process of getting tenure may weed out those who might later need it, reform is called for. Reform of tenure must take into account not only the Salieri-effect, but also Thomas Kuhn's popular philosophical attack on independent thought and the tendency towards the use of minimal standards, resulting from the professionalization of research, to block work which is more than minimal. Reform of various institutions to encourage autonomy is needed so that those who receive tenure use it for its intended purpose.
Critical developmental periods of increased plasticity program ritualized behavior
Authors: Swain James E.
Published: February 2007

The consideration of humans going through sensitive periods of life, such as childhood and the early postpartum, may be helpful in understanding the cognitive and evolutionary puzzle of human rituals. During such periods, certain brain systems may mediate an increased susceptibility to learn new behaviors, rational or irrational.
Uncertainty and rituals
Authors: Woody Erik Z. , Szechtman Henry
Published: February 2007

Boyer & Lienard (B&L) elegantly elaborate the links between normal motivational systems and psychopathology and address the evolutionary and cultural context of ritualized behaviors. However, their model omits a key property of the security-motivation (hazard-precaution) system, and this property suggests that ritualized behavior may generate an alternate satiety signal by substituting, in place of uncertainty, a problem that is verifiably solvable.
School-based Internet-tailored fruit and vegetable education combined with brief counselling increases children's awareness of intake levels
Authors: Mangunkusumo Resiti T , Brug Johannes , de Koning Harry J , van der Lei Johan , Raat Hein
Published: February 2007

Objective

Children's fruit/vegetable intake is still below recommended levels. This study applied Internet-tailored advice for schoolchildren and Internet-supported brief dietary counselling (with child and parent) within preventive health care to promote fruit/vegetable intake.

Setting/subjects

The study involved 30 seventh-grade classes (16 in the intervention group and 14 in the control group) with a total of 675 children aged 9–12 years, of whom 495 were allowed to participate.

Design

A cluster-randomised baseline–post-test experimental design was applied. During school hours, all children completed Internet-administered questionnaires on fruit/vegetable intake and related determinants. Children in the intervention group received immediate online individually tailored nutrition feedback. For each child in the intervention group, a nurse received information concerning the assessment of fruit/vegetable intake via the Internet to support a 5 min counselling protocol to promote fruit/vegetable intake. Children completed a similar post-test questionnaire 3 months after the first assessment. Intention-to-treat analyses were conducted using multilevel regression analyses.

Results

A total of 486 children (98% of 495) participated (263 in the intervention group, 223 in the control group); 240 child–parent couples in the intervention group attended the counselling. Awareness of inadequate fruit intake (odds ratio (OR) = 3.0; 95% confidence interval (CI) = 1.8–5.3) and knowledge of recommended vegetable intake levels (OR = 2.7; 95% CI = 1.8–4.1) were significantly more likely at post-test in the intervention group than in the control group. No significant effects were found on intake or other determinants.

Conclusions

A compact, integrated two-component intervention can induce positive changes in knowledge and awareness of intake levels of fruit/vegetables among schoolchildren. To induce changes in intake levels, more comprehensive interventions may be needed.
Which food-related behaviours are associated with healthier intakes of fruits and vegetables among women?
Authors: Crawford David , Ball Kylie , Mishra Gita , Salmon Jo , Timperio Anna
Published: February 2007

Objective

To examine associations between shopping, food preparation, meal and eating behaviours and fruit and vegetable intake among women.

Design

Cross-sectional survey.

Setting

Community-based sample from metropolitan Melbourne, Australia.

Subjects

A sample of 1136 women aged 18–65 years, randomly selected from the electoral roll.

Results

Food-related behaviours reflecting organisation and forward-planning, as well as enjoyment of and high perceived value of meal shopping, preparation and consumption were associated with healthier intakes of fruits and vegetables. For example, women who more frequently planned meals before they went shopping, wrote a shopping list, enjoyed food shopping, planned in the morning what they will eat for dinner that night, planned what they will eat for lunch, reported they enjoy cooking, liked trying new recipes and who reported they sometimes prepare dishes ahead of time were more likely to consume two or more servings of vegetables daily. Conversely, women who frequently found cooking a chore, spent less than 15 minutes preparing dinner, decided on the night what they will eat for dinner, ate in a fast-food restaurant, ate takeaway meals from a fast-food restaurant, ate dinner and snacks while watching television and who frequently ate on the run were less likely to eat two or more servings of vegetables daily.

Conclusions

Practical strategies based on these behavioural characteristics could be trialled in interventions aimed at promoting fruit and vegetable consumption among women.
Parent outcome expectancies for purchasing fruit and vegetables: a validation
Authors: Baranowski Tom , Watson Kathy , Missaghian Mariam , Broadfoot Alison , Baranowski Janice , Cullen Karen , Nicklas Theresa , Fisher Jennifer , O'Donnell Sharon
Published: February 2007

Objective

To validate four scales – outcome expectancies for purchasing fruit and for purchasing vegetables, and comparative outcome expectancies for purchasing fresh fruit and for purchasing fresh vegetables versus other forms of fruit and vegetables (F&V).

Design

Survey instruments were administered twice, separated by 6 weeks.

Setting

Recruited in front of supermarkets and grocery stores; interviews conducted by telephone.

Subjects

One hundred and sixty-one food shoppers with children (18 years or younger).

Results

Single dimension scales were specified for fruit and for vegetable purchasing outcome expectancies, and for comparative (fresh vs. other) fruit and vegetable purchasing outcome expectancies. Item Response Theory parameter estimates revealed easily interpreted patterns in the sequence of items by difficulty of response. Fruit and vegetable purchasing and fresh fruit comparative purchasing outcome expectancy scales were significantly correlated with home F&V availability, after controlling for social desirability of response. Comparative fresh vegetable outcome expectancy scale was significantly bivariately correlated with home vegetable availability, but not after controlling for social desirability.

Conclusion

These scales are available to help better understand family F&V purchasing decisions.
Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems
Authors: Barrett J. E. , Virginia R. A. , Lyons W. B. , McKnight D. M. , Priscu J. C. , Doran P. T. , Fountain A. G. , Wall D. H. , Moorhead D. L.
Published: February 2007

Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10–106 years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.
Ice core evidence for a very tight link between North Atlantic and east Asian glacial climate
Authors: Ruth Urs , Bigler Matthias , Röthlisberger Regine , Siggaard‐Andersen Marie‐Louise , Kipfstuhl Sepp , Goto‐Azuma Kumiko , Hansson Margareta E. , Johnsen Sigfus J. , Lu Huayu , Steffensen Jørgen P.
Published: February 2007

Corresponding millennial‐scale climate changes have been reported from the North Atlantic region and from east Asia for the last glacial period on independent timescales only. To assess their degree of synchrony we suggest interpreting Greenland ice core dust parameters as proxies for the east Asian monsoon systems. This allows comparing North Atlantic and east Asian climate on the same timescale in high resolution ice core data without relative dating uncertainties. We find that during Dansgaard‐Oeschger events North Atlantic region temperature and east Asian storminess were tightly coupled and changed synchronously within 5–10 years with no systematic lead or lag, thus providing instantaneous climatic feedback. The tight link between North Atlantic and east Asian glacial climate could have amplified changes in the northern polar cell to larger scales. We further find evidence for an early onset of a Younger Dryas‐like event in continental Asia, which gives evidence for heterogeneous climate change within east Asia during the last deglaciation.
Migration characteristics of seismic tremors in the northern Cascadia margin
Authors: Kao Honn , Shan Shao‐Ju , Rogers Garry , Dragert Herb
Published: February 2007

Seismic waveforms from a dense regional array were analyzed to study episodic tremor‐and‐slip (ETS) events in northern Cascadia. The April 2005 episode occurred mostly in northern Vancouver Island (VI) where the Explorer plate subducts beneath the North America plate, while the May 2005 episode was mainly in middle VI. All tremor occurrences are positively correlated with the presence of subducted slabs. Besides the “steady” along‐strike migration and “halting” behavior found in previous ETS events, a new pattern (“jumping”) is found this time. Visual inspection of previous seismic records suggests that the jumping behavior is probably common to ETS tremors in all regions of VI. The majority of tremors occurred between 25 and 45 km depth in places where local seismicity is sparse or absent. Our observations are compatible with the interpretation that fluids released from dehydration of subducted materials are involved in tremor generation.
Simulations of solar wind charge exchange X‐ray emissions at Venus
Authors: Gunell H. , Kallio E. , Jarvinen R. , Janhunen P. , Holmström M. , Dennerl K.
Published: February 2007

A hybrid simulation of the solar wind‐Venus interaction and a test particle simulation of heavy ion trajectories near Venus are used to compute the contribution from solar wind charge exchange processes to the X‐ray emission from Venus. It is found that the X‐ray halo caused by the solar wind charge exchange process at Venus is confined to lower altitudes than at Mars, and that the structure on the ion gyro radius scale that is seen in X‐ray images of Mars is absent at Venus.
Role of suction dynamics in evolution of intertidal sandy flats: Field evidence, experiments, and theoretical model
Authors: Sassa Shinji , Watabe Yoichi
Published: February 2007

In this paper we present and discuss the role of the dynamics of suction, that is, negative pore water pressure relative to atmospheric air pressure, in the evolution of intertidal sandy flats. This is done through the combined use of field evidence, laboratory experiments, and a theoretical model. Field observations were performed in the estuary of Obitsu River located in the east coast of Tokyo Bay, Japan. Laboratory experiments were performed in a calibration chamber as well as in a laterally scaled model flat subjected to water/groundwater level variations. The present study demonstrates that the suction dynamics associated with the tide‐induced groundwater level variations play a substantial role in the temporospatial evolutions of voids, stiffness, and surface shear strength in cyclically exposed and submerged soil. The suction‐induced void state changes are a consequence of cyclic elastoplastic contraction of the soil and are accompanied by distinct morphological changes, despite the lack of significant surface shear stresses acting on the soil. Such soil behavior occurs in regions where suction develops above the groundwater level during low tides and strongly depends on the way in which such suction develops. Discussions are made on how these suction dynamics effects could contribute, via feedback involved in surface transport processes, to the overall morphological evolution of cross‐shore intertidal flat soils.
A finite difference time domain model for the Titan ionosphere Schumann resonances
Authors: Navarro E. A. , Soriano A. , Morente J. A. , Portí J. A.
Published: February 2007

This paper presents a numerical approach to model the electrical properties of Titan's atmosphere. The finite difference time domain technique is applied to model the atmosphere of Saturn's satellite in order to determine Schumann resonant frequencies and electromagnetic field distributions at the extremely low frequency range. Spherical coordinates are employed, and periodic boundary conditions are implemented in order to exploit the symmetry in rotation of the celestial body. Results are compared with a previous model using the transmission line matrix method up to 180 km altitude. For the first time a numerical FDTD model up to 800 km altitude is carried out, and we report lower frequencies than other previous models. The Schumann resonances of Titan were measured by the NASA–European Space Agency Cassini‐Huygens mission in January 2005. Our mathematical model can be modified to change the conductivity profiles to explain the observed experimental data.
Analgesic actions of N‐arachidonoyl‐serotonin, a fatty acid amide hydrolase inhibitor with antagonistic activity at vanilloid TRPV1 receptors
Authors: Maione S , De Petrocellis L , de Novellis V , Moriello A Schiano , Petrosino S , Palazzo E , Rossi F Sca , Woodward D F , Di Marzo V
Published: February 2007

Background and purpose:

N‐arachidonoyl‐serotonin (AA‐5‐HT) is an inhibitor of fatty acid amide hydrolase (FAAH)‐catalysed hydrolysis of the endocannabinoid/ endovanilloid compound, anandamide (AEA). We investigated if AA‐5‐HT antagonizes the transient receptor potential vanilloid‐1 (TRPV1) channel and, as FAAH and TRPV1 are targets for analgesic compounds, if it exerts analgesia in rodent models of hyperalgesia.

Experimental approach:

AA‐5‐HT was tested in vitro, on HEK‐293 cells overexpressing the human or the rat recombinant TRPV1 receptor, and in vivo, in rats and mice treated with formalin and in rats with chronic constriction injury of the sciatic nerve. The levels of the endocannabinoids, AEA and 2‐arachidonoylglycerol, in supraspinal (periaqueductal grey, rostral ventromedial medulla), spinal or peripheral (skin) tissues were measured.

Key results:

AA‐5‐HT behaved as an antagonist at both rat and human TRPV1 receptors (IC50=37‐40 nM against 100 nM capsaicin). It exerted strong analgesic activity in all pain models used here. This activity was partly due to FAAH inhibition, elevation of AEA tissue levels and indirect activation of cannabinoid CB1 receptors, as it was reversed by AM251, a CB1 antagonist. AA‐5‐HT also appeared to act either via activation/desensitization of TRPV1, following elevation of AEA, or as a direct TRPV1 antagonist, as suggested by the fact that its effects were either reversed by capsazepine and 5′‐iodo‐resiniferatoxin, two TRPV1 antagonists, or mimicked by these compounds administered alone.

Conclusions and implications:

Possibly due to its dual activity as a FAAH inhibitor and TRPV1 antagonist, AA‐5‐HT was highly effective against both acute and chronic peripheral pain.

British Journal of Pharmacology (2007) 150, 766–781. doi:10.1038/sj.bjp.0707145
Thickness dependence of the high-frequency magnetic permeability in amorphous Fe73.5Cu1Nb3Si13.5B9 thin films
Authors: Viegas A. D. C. , Corrêa M. A. , Santi L. , da Silva R. B. , Bohn F. , Carara M. , Sommer R. L.
Published: February 2007

Field-dependent transverse permeability characterization of amorphous thin films with nominal composition Fe73.5Cu1Nb3Si13.5B9 was performed for frequencies in the range of 100kHz–1.8GHz. Dynamic and static magnetic properties were investigated in films with thickness in the range from 21to5000nm. Samples with thicknesses below 85nm exhibit a well-defined in-plane uniaxial anisotropy and uniform ferromagnetic resonance modes. Samples thicker than 85nm were found to be magnetically isotropic in the plane, with complex magnetic dynamics depicted by several ferromagnetic resonance modes detected at relatively low fields. The results are discussed in terms of the stress contribution to the magnetic anisotropy of the samples.
First principles study of the HfO2∕SiO2 interface: Application to high-k gate structures
Authors: Ha Jeong-Hee , McIntyre Paul C. , (KJ) Cho Kyeongjae
Published: February 2007

Density functional theory simulations of HfO2∕SiO2 interfaces predict the presence of midgap states associated with nonbonding Hf d electrons which result from the reduced oxygen coordination of near-interface Hf ions. These states are expected to be unoccupied in actual device structures, producing a high density of positive fixed charge during the operation of Si field effect devices containing high permittivity HfO2 dielectrics. Our results further demonstrate how the segregation of electronegative species to the HfO2∕SiO2 interface can remove gap states by accepting the nonbonding electrons.
Cross-plane Seebeck coefficient of ErAs:InGaAs∕InGaAlAs superlattices
Authors: Zeng Gehong , Zide Joshua M. O. , Kim Woochul , Bowers John E. , Gossard Arthur C. , Bian Zhixi , Zhang Yan , Shakouri Ali , Singer Suzanne L. , Majumdar Arun
Published: February 2007

We characterize cross-plane and in-plane Seebeck coefficients for ErAs:InGaAs∕InGaAlAs superlattices with different carrier concentrations using test patterns integrated with microheaters. The microheater creates a local temperature difference, and the cross-plane Seebeck coefficients of the superlattices are determined by a combination of experimental measurements and finite element simulations. The cross-plane Seebeck coefficients are compared to the in-plane Seebeck coefficients and a significant increase in the cross-plane Seebeck coefficient over the in-plane Seebeck coefficient is observed. Differences between cross-plane and in-plane Seebeck coefficients decrease as the carrier concentration increases, which is indicative of heterostructure thermionic emission in the cross-plane direction.
On the heat capacity of adsorbed phases using molecular simulation
Authors: Birkett G. R. , Do D. D.
Published: February 2007

The heat capacities of argon, ammonia, and methanol on carbon black at 87.3, 240, and 300K, respectively, have been investigated. The carbon black surface has been modeled with and without carbonyl groups. Part of this investigation is a decomposition of the heat capacity into its contributions from the different interaction potentials of an adsorption system. All systems show a spectrum of heat capacity versus loading, and this behavior depends on the carbonyl configuration present on the surface. For methanol and ammonia the variation of the heat capacity between the two for the same carbonyl configurations is greater than the variation in the heat of adsorption. Heat capacities of methanol and ammonia are generally dominated by fluid-fluid interactions due to the strong association of fluid particles through hydrogen bonding. The difference in the heat capacity behavior of the two fluids is an indicator of their different clustering behaviors on the carbon black surface. The presence of carbonyl groups reduces the fluid-fluid contributions to the heat capacity. This is due to the compensation of fluid-fluid interactions with fluid-functional group interactions. At 87.3K a first layer transition to a solidlike state is present for argon and results in a large peak in the heat capacity on a bare surface. The presence of functional groups greatly reduces this peak in the heat capacity by disrupting the packing of argon on the surface and preventing a transition to a solidlike state.
Theoretical study of quantum well infrared photodetectors with asymmetric well and barrier structures for broadband photodetection
Authors: Liu W. , Zhang D. H. , Huang Z. M. , Fan W. J.
Published: February 2007

The n-type InGaAs∕AlxGa1−xAs quantum well infrared photodetector (QWIP) with asymmetric graded barriers for broadband detection has been investigated theoretically based on the eight-band k∙p model. It is found that the intersubband transitions from the ground state to all bound and continuum excited states contribute to the overall absorption and the bound-to-continuum (B-to-C) transitions dominate. The superposition of the bound-to-bound and B-to-C transitions results in a broad detection bandwidth, and both the detected wavelength and bandwidth can be tuned by the applied voltage. The analysis method is also applicable to the GaAs∕InxGa1−xAs∕InyGa1−yAs QWIP with step quantum wells. The calculated results are consistent with the reported experimental observations.
On the strong and narrow absorption signature in lactose at 0.53THz
Authors: Brown E. R. , Bjarnason J. E. , Fedor A. M. , Korter T. M.
Published: February 2007

The authors report on the room-temperature characterization of a narrow absorption signature in an organic molecular solid (α-lactose monohydrate) centered around 530GHz and having a full width at half maximum as small as 23GHz. Three different spectrometric techniques were applied, two of them (tunable photomixing and tunable frequency multiplication) having a high enough resolution (⪡100MHz) to accurately curve fit the signature and determine that it is much better described by a Lorentzian than a Gaussian function. The Lorentzian model provides an estimate of 14ps for the damping time associated with this signature.
Nonlinear real-life signal detection with a supervised principal components analysis
Authors: Zhou C. T. , Cai T. X. , Cai T. F.
Published: February 2007

A novel strategy named supervised principal components analysis for the detection of a target signal of interest embedded in an unknown noisy environment has been investigated. There are two channels in our detection scheme. Each channel consists of a nonlinear phase-space reconstructor (for embedding a data matrix using the received time series) and a principal components analyzer (for feature extraction), respectively. The output error time series, which results from the difference of both eigenvectors of the correlation data matrices from these two channels, is then analyzed using time-frequency tools, for example, frequency spectrum or Wigner-Ville distribution. Experimental results based on real-life electromagnetic data are presented to demonstrate the detection performance of our algorithm. It is found that weak signals hidden beneath the noise floor can be detected. Furthermore, the robustness of the detection performance clearly illustrated that signal frequencies can be extracted when the signal power is not too low.
Vortex dynamics in Permalloy disks with artificial defects: Suppression of the gyrotropic mode
Authors: Kuepper K. , Bischoff L. , Akhmadaliev Ch. , Fassbender J. , Stoll H. , Chou K. W. , Puzic A. , Fauth K. , Dolgos D. , Schütz G. , Van Waeyenberge B. , Tyliszczak T. , Neudecker I. , Woltersdorf G. , Back C. H.
Published: February 2007

The dynamics of magnetic vortices in thin Permalloy disks having artificial defects in the form of small holes at different locations within the disk has been investigated by means of frequency-domain spatially resolved ferromagnetic resonance. It is found that the vortex can be effectively captured by such a defect. Consequently the commonly observed gyrotropic vortex motion in an applied microwave field of 1mT is suppressed. However, if in addition a static magnetic field of at least 4.3mT is applied, the vortex core is nucleated from the artificial defect and a modified gyrotropic motion starts again.
Pentacene-based thin film transistors with titanium oxide-polystyrene/polystyrene insulator blends: High mobility on high K dielectric films
Authors: Jung Cecile , Maliakal Ashok , Sidorenko Alexander , Siegrist Theo
Published: February 2007

High K titanium oxide-polystyrene TiO2-PS nanocomposite has been blended with PS to generate gate dielectric films with permittivities ranging from 2.5 to 8 in order to investigate permittivity effects on pentacene thin film transistor performance. An order of magnitude increase in saturation mobility is observed for TiO2-PS (K=8) as compared to PS devices (K=2.5). Morphological differences for pentacene grown on TiO2-PS∕PS dielectrics are thought to be responsible for the observed mobility enhancements. The high performance of pentacene on TiO2-PS devices suggests that high permittivity films are compatible with high mobility devices.
Crystalline Pr2O3 monolayers on Si(111)
Authors: Jeutter N. M. , Moritz W. , Sidorenko A. , Stierle A.
Published: February 2007

In this study the authors present an x-ray analysis of the structure and of the interface of 1 ML Pr2O3 on Si(111). The x-ray analysis shows that the interface is formed of a Si–O–Pr bond with Pr above the T4 adsorption site of silicon (111). The layer exhibits a thickness of 0.6nm corresponding to one bulk unit cell from the hexagonal phase of Pr2O3. The layer is well ordered with Pr–O bond lengths close to the bulk values and a Si–O distance of 0.18nm.
Miniaturized diamond field-effect transistors for application in biosensors in electrolyte solution
Authors: Song Kwang-Soup , Hiraki Takahiro , Umezawa Hitoshi , Kawarada Hiroshi
Published: February 2007

The authors fabricated diamond solution-gate field-effect transistors (SGFETs) with miniaturization of the channel length to 5μm by photolithography. The channel surface was directly functionalized with amine by ultraviolet irradiation in an ammonia gas for 4h and aminated diamond SGFETs were sensitive to pH by 40mV∕pH. Urease was immobilized on the amine-modified channel surface, which was sensitive to urea by 27μA/decade from 10−5M to 10−2M. The authors fabricated submicron-sized (500nm) diamond SGFETs using electron-beam lithography. The transconductance (gm) was 56mS∕mm, which was 930-fold greater than that of the 500μm channel length.
Origin of the red luminescence band in photoluminescence spectra of ZnSe nanowires
Authors: Philipose U. , Yang S. , Xu T. , Ruda Harry E.
Published: February 2007

In this work, the origin of the deep level, defect related photoluminescence emission band in ZnSe is investigated. Using the dependence of the peak energy on excitation intensity, it was shown to originate from donor-acceptor pair recombination. The binding energy of the donor-acceptor pair was estimated to be 18±0.5meV and the shallow impurity Bohr radius was estimated to be 9.1±0.2nm. Using a postgrowth annealing treatment in a Zn atmosphere, the two species involved in the donor-acceptor pair recombination process were attributed to Zn vacancies and Zn interstitials.
Vibrational study of hydrogen bonding to ion irradiated diamond surfaces
Authors: Bertin M. , Lafosse A. , Azria R. , Michaelson Sh. , Ternyak O. , Hoffman A.
Published: February 2007

High resolution electron energy loss spectroscopy has been used to probe hydrogenated diamond film surfaces exposed to 1keV Ar+ ions at a dose of ∼1015cm−2 and thermal annealing. The defects induced on the upper atomic layers were identified with regard to the different hydrogenated species hybridization states as well as their thermal stability. Ion irradiation resulted in the coexistence of a partially hydrogenated disordered near surface region including CH species bonded in sp, sp2, and sp3 bonding configurations and CC dimers. Thermal annealing of the ion beam irradiated hydrogenated surface leads to complete hydrogen desorption at ∼650°C. This temperature is significantly lower compared to a well defined diamond surface for which an annealing temperature above 900°C is needed.
Characteristics of both carriers with polarization in diode-type CdTe x-ray detectors
Authors: Okada Kyoko , Sakurai Yoshiharu , Suematsu Hiroyoshi
Published: February 2007

The authors have measured pulse shapes (pulse height and rise time) in diode- and Ohmic-type CdTe x-ray detectors in order to investigate the polarization phenomena observed in diode-type detectors. Using α particles incident on either cathode or anode side, they can independently focus on electron or hole movement. The authors find that the carrier movements are different between the two types of detectors. This implies that, in the diode-type detectors, electrons are trapped in the vicinity of the In electrode (anode), while holes are trapped and detrapped throughout the CdTe crystal or in the vicinity of the Pt electrode (cathode).
Blue lasing at room temperature in high quality factor GaN∕AlInN microdisks with InGaN quantum wells
Authors: Simeonov D. , Feltin E. , Bühlmann H.-J. , Zhu T. , Castiglia A. , Mosca M. , Carlin J.-F. , Butté R. , Grandjean N.
Published: February 2007

The authors report on the achievement of optically pumped III-V nitride blue microdisk lasers operating at room temperature. Controlled wet chemical etching of an AlInN interlayer lattice matched to GaN allows forming inverted cone pedestals. Whispering gallery modes are observed in the photoluminescence spectra of InGaN∕GaN quantum wells embedded in the GaN microdisks. Typical quality factors of several thousands are found (Q>4000). Laser action at ∼420nm is achieved under pulsed excitation at room temperature for a peak power density of 400kW∕cm2. The lasing emission linewidth is down to 0.033nm.
Plasma etch method for extreme ultraviolet lithography photomask
Authors: Wu Banqiu , Kumar Ajay
Published: February 2007

Studies on extreme ultraviolet mask etch were carried out by using the Gibbs energy minimization method to select plasma etch chemistries and to determine product volatility when etching absorber material to ensure a clean process and chamber operation. A self-mask method and corresponding etch conditions were proposed and experimentally examined using the antireflective portion of an absorber layer as a hard mask for the bulk absorber layer beneath. This approach overcame the intrinsic soft mask disadvantage of large etch critical dimension (CD) bias and low pattern transfer fidelity, producing significantly reduced etch CD bias (2nm) and high pattern transfer fidelity.
Growth and properties of gradient free sol-gel lead zirconate titanate thin films
Authors: Calame F. , Muralt P.
Published: February 2007

Pb ( Zr x , Ti 1 − x ) O 3 thin films of homogeneous composition were synthesized by means of a modified sol-gel route on Pt(111)∕TiOx∕SiO2∕Si substrates. The gradient in B-site composition as obtained by standard routes could be lowered, reducing Zr concentration fluctuations form ±12to±2.5at.%. The 2μm thick, dense and crack-free films exhibited a {100}-texture index of 98.4%. Grain diameters increased by 50%. Dielectric and piezoelectric properties were remarkably improved. The relative dielectric constant ε33,f was obtained as 1620, and the remanent transverse piezoelectric coefficient e31,f was measured as −17.7Cm2.
Reduction of traps and improvement of carrier lifetime in 4H-SiC epilayers by ion implantation
Authors: Storasta Liutauras , Tsuchida Hidekazu
Published: February 2007

The authors report a significant reduction in deep level defects and improvement of carrier lifetime in 4H-SiC material after carrying out carbon or silicon ion implantation into the shallow surface layer of 250nm and subsequent annealing at 1600°C or higher temperature. Reduction of Z1∕2 and EH6∕7 traps from 3×1013cm−3 to below the detection limit (5×1011cm−3) was observed by deep level transient spectroscopy in the material 4μm underneath the implanted layer. Minority carrier lifetime almost doubled in the implanted samples compared to the unimplanted samples. The authors propose that the implanted layer acts as a source of carbon interstitials which indiffuse during annealing and accelerate annealing out of grown-in defects in the layer underneath the implanted region.
Metallic slit waveguide for dispersion-free low-loss terahertz signal transmission
Authors: Wächter Markus , Nagel Michael , Kurz Heinrich
Published: February 2007

Transmission characteristics of a metallic waveguide are presented combining negligible dispersion, very low attenuation, and two-dimensional mode confinement. The waveguide is fabricated by sawing a 270μm wide slit through a 40mm wide and 300μm thick silicon slab and subsequent metalization of all faces. Single-mode terahertz pulses propagating through the slit are excited at one end of the waveguide using a photoconductive antenna array and detected with a freely positionable photoconductive probe tip. Low-loss propagation with negligible group velocity dispersion is observed in the 0.1–1.0THz frequency range. Compared to former approaches considerably stronger mode confinement is achieved.
Contrapuntal Geographies of Threat and Security: The United States, India, and Israel
Authors: Oza Rupal
Published: February 2007

This paper is concerned with discourses of threat and security deployed by the United States and India after September 11. In the context of the United States these discourses have been used to justify war in Afghanistan and in Iraq and have revolved around the subject of the Muslim male as perpetually dangerous. Eager to support the United States in its war against terror, India echoed the construction of the Muslim male as dangerous, which served to fulfill India's own internal and regional supremacy agendas. Bolstered, therefore, by the emerging discourse of Muslim terrorists, in 2002 the Hindu Right was complicit in orchestrating genocide against Muslims in Gujarat where 2000 Muslims were killed and 150000 Muslims were rendered homeless. Examining these and other incidents, I examine the similarity in discourses of threat and security deployed by the United States and India. I argue that the similarity in discourses emerges because of a particular understanding of time and space. I make two interconnected arguments: first, time and the very understanding and construction of history are distorted, collapsed, and twisted such that revenge for past atrocities and the threat of future ones are used to justify preemptive military action. Second, there is a particular geography to this doctrine of threat and security that is being established by demarcating us against them. This new spatial arrangement is being formed contingent on a particular understanding of time and history as a linear singular narrative and on the creation of political alliances between India, the United States, and Israel.
Protection against inflammation- and autoantibody-caused fetal loss by the chemokine decoy receptor D6
Authors: Martinez de la Torre Yeny , Buracchi Chiara , Borroni Elena M. , Dupor Jana , Bonecchi Raffaella , Nebuloni Manuela , Pasqualini Fabio , Doni Andrea , Lauri Eleonora , Agostinis Chiara , Bulla Roberta , Cook Donald N. , Haribabu Bodduluri , Meroni Pierluigi , Rukavina Daniel , Vago Luca , Tedesco Francesco , Vecchi Annunciata , Lira Sergio A. , Locati Massimo , Mantovani Alberto
Published: February 2007

Fetal loss in animals and humans is frequently associated with inflammatory conditions. D6 is a promiscuous chemokine receptor with decoy function, expressed in lymphatic endothelium, that recognizes and targets to degradation most inflammatory CC chemokines. Here, we report that D6 is expressed in placenta on invading extravillous trophoblasts and on the apical side of syncytiotrophoblast cells, at the very interface between maternal blood and fetus. Exposure of D6−/−pregnant mice to LPS or antiphospholipid autoantibodies results in higher levels of inflammatory CC chemokines and increased leukocyte infiltrate in placenta, causing an increased rate of fetal loss, which is prevented by blocking inflammatory chemokines. Thus, the promiscuous decoy receptor for inflammatory CC chemokines D6 plays a nonredundant role in the protection against fetal loss caused by systemic inflammation and antiphospholipid antibodies.
Substrate product equilibrium on a reversible enzyme, triosephosphate isomerase
Authors: Rozovsky Sharon , McDermott Ann E.
Published: February 2007

The highly efficient glycolytic enzyme, triosephosphate isomerase, is expected to differentially stabilize the proposed stable reaction species: ketone, aldehyde, and enediol(ate). The identity and steady-state populations of the chemical entities bound to triosephosphate isomerase have been probed by using solid- and solution-state NMR. The
13
C-enriched ketone substrate, dihydroxyacetone phosphate, was bound to the enzyme and characterized at steady state over a range of sample conditions. The ketone substrate was observed to be the major species over a temperature range from −60°C to 15°C. Thus, there is no suggestion that the enzyme preferentially stabilizes the reactive intermediate or the product. The predominance of dihydroxyacetone phosphate on the enzyme would support a mechanism in which the initial proton abstraction in the reaction from dihydroxyacetone phosphate to
d
-glyceraldehyde 3-phosphate is significantly slower than the subsequent chemical steps.