bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymatic direct synthesis of acrylic acid esters of mono‐ and disaccharides
Authors: Tsukamoto Junko , Haebel Sophie , Valença Gustavo P. , Peter Martin G. , Franco Telma T.
Published: June 2008

BACKGROUND: There is an increased need to replace materials derived from fossil sources by renewables. Sugar‐cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the preparation of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous preparation of protected sugar derivatives, such as glycosides, or activated acrylates, such as vinyl acrylate.

RESULTS: Lipase catalyzed esterification of three mono‐ and two disaccharides with acrylic acid, in the presence or absence of molecular sieves was investigated. The reactions were monitored by high‐performance liquid chromatography (HPLC) and the products were analyzed by matrix‐assisted laser desorption ionization–time of flight (MALDI‐TOF) mass spectrometry. The main products are mono‐ and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was observed for the D‐glucose and D‐fructose, followed by D‐xylose and D‐maltose. Molecular sieves had no pronounced effect on the conversion

CONCLUSIONS: A feasible method is described to produce and to characterize sugar acrylates, including those containing more than two acrylate groups. The process for production of these higher esters could potentially be optimized further to produce molecules for cross‐linking in acrylate polymerization and other applications. The direct enzymatic esterification of free carbohydrates with acrylic acid is unprecedented. Copyright © 2008 Society of Chemical Industry
Fourier multipliers on power‐weighted Hardy spaces
Authors: Quek T. S.
Published: June 2008

Using Herz spaces, we obtain a sufficient condition for a bounded measurable function on ℝn to be a Fourier multiplier on Hpα (ℝn ) for 0 < p < 1 and –n < α ≤ 0. Our result is sharp in a certain sense and generalizes a recent result obtained by Baernstein and Sawyer. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure, dynamics, and binding thermodynamics of the v‐Src SH2 domain: Implications for drug design
Authors: Taylor Jonathan D. , Ababou Abdessamad , Fawaz Radwan R. , Hobbs Christopher J. , Williams Mark A. , Ladbury John E.
Published: June 2008

SH2 domains provide fundamental recognition sites in tyrosine kinase‐mediated signaling pathways which, when aberrant, give rise to disease states such as cancer, diabetes, and immune deficiency. Designing specific inhibitors that target the SH2 domain‐binding site, however, have presented a major challenge. Despite well over a decade of intensive research, clinically useful SH2 domain inhibitors have yet to become available. A better understanding of the structural, dynamic, and thermodynamic contributions to ligand binding of individual SH2 domains will provide some insight as to whether inhibitor development is possible. We report the first high resolution solution structure of the apo‐v‐Src SH2 domain. This is accompanied by the analysis of backbone dynamics and pKa values within the apo‐ and peptide‐bound states. Our results indicate that the phosphotyrosine (pY) pocket is tightly structured and hence not adaptable to exogenous ligands. On the other hand, the pocket which accommodates residues proximal and C‐terminal of the pY (pY + 3) or so‐called specificity determining region, is a large dynamic‐binding surface. This appears to allow a high level of promiscuity in binding. Binding of a series of synthetic, phosphotyrosyl, peptidomimetic compounds designed to explore interactions in the pY + 3 pocket further demonstrates the ability of the SH2 domain to accommodate diverse ligands. The thermodynamic parameters of these interactions show dramatic enthalpy/entropy compensation. These data suggest that the v‐Src SH2 domain does not have a highly specific secondary‐binding site, which clearly presents a major hurdle to design selective inhibitors. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Guiding conformation space search with an all‐atom energy potential
Authors: Brunette TJ , Brock Oliver
Published: June 2008

The most significant impediment for protein structure prediction is the inadequacy of conformation space search. Conformation space is too large and the energy landscape too rugged for existing search methods to consistently find near‐optimal minima. To alleviate this problem, we present model‐based search, a novel conformation space search method. Model‐based search uses highly accurate information obtained during search to build an approximate, partial model of the energy landscape. Model‐based search aggregates information in the model as it progresses, and in turn uses this information to guide exploration toward regions most likely to contain a near‐optimal minimum. We validate our method by predicting the structure of 32 proteins, ranging in length from 49 to 213 amino acids. Our results demonstrate that model‐based search is more effective at finding low‐energy conformations in high‐dimensional conformation spaces than existing search methods. The reduction in energy translates into structure predictions of increased accuracy. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Study of cross‐sections of magnetite thin films by means of electron backscatter diffraction (EBSD)
Authors: Koblischka‐Veneva A. , Koblischka M. R. , Mücklich F. , Hartmann U.
Published: June 2008

By means of electron backscatter diffraction (EBSD), we studied the grain orientation of cross‐sections of magnetite (Fe3O4) thin films grown on (001) oriented MgO substrates. Earlier studies showed that the magnetic properties of the magnetite films are dominated by the presence of so‐called anti‐phase boundaries (APBs). The use of cross‐sections of thin‐films enables to study the growth mechanism in a more direct way. The EBSD maps reveal that the first magnetite layer on the MgO substrate is comprised of many small, misoriented magnetite grains. Subsequent layers show the desired (001) orientation with a ±5° misorientation. The misorientations found in the cross‐section of the film resemble those obtained in EBSD measurements at the sample surface. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase transition in sodium bismuth tungstate NaBi(WO4)2 – acoustic studies
Authors: Khusravbekov L. , Charnaya E. V. , Tien Cheng , Rakhimov I. K. , Borisov B. F. , Salakhutdinov M. I. , Ulfatshoev M. M.
Published: June 2008

Acoustic studies of sodium bismuth tungstate, NaBi(WO4)2, single crystal were carried out in the temperature range from 290 K to 340 K. Strong anomalies in ultrasound velocity and attenuation were observed above room temperature for both longitudinal and transverse waves. The results obtained suggested a phase transition at 319.2 K. The order parameter responsible for the phase transition was found to be coupled linearly with strains in transverse acoustic waves and nonlinearly with those in longitudinal waves. It was suggested that the phase transition is related with substitutional ordering of the Na+ and Bi3+ ions at the cation sites. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Competitive intensity and collaboration: impact on firm growth across technological environments
Authors: Ang Siah Hwee
Published: June 2008

This article investigates the impact of competitive intensity and collaboration on firm growth across technological environments. I propose that competitive intensity determines the likelihood of firm collaboration, and that the interaction of competitive intensity and collaboration influences firm growth. These relationships are, in turn, moderated by industry‐level technological intensity. Analyzing 1,004 firms and 378 collaborations from the manufacturing sector in Singapore, I find that firms facing high or low levels of competitive intensity collaborate less often than those facing moderate levels of competitive intensity. Industry technology intensity moderates this relationship, with a stronger inverted‐U‐shaped association between competitive intensity and collaboration in more technology intensive industries. Collaboration leads to higher growth for firms facing lower levels of competitive intensity than for firms facing higher levels of competitive intensity only in more technology intensive industries. In technologically less intensive industries, collaboration leads to higher growth for firms facing higher levels of competitive intensity as compared to those facing lower levels of competitive intensity. These findings have important implications for competitive and collaborative dynamics for firm growth in different technological environments. Copyright © 2008 John Wiley & Sons, Ltd.
Performance effects of imitative entry
Authors: Ethiraj Sendil K. , Zhu David H.
Published: June 2008

This article examines how waiting to imitate a product affects the performance of the imitator compared to the innovator. Specifically, we address two research questions. Under what conditions does imitation erode the advantage of the innovator? What strategies of imitators help overcome the innovator's advantage? Our main argument is that the increasing availability of information on the innovator's product increases the imitator's returns to waiting. With this increasing availability of information, imitators' products transition from those that are horizontally differentiated (products are similar in quality but differ in their attributes) to those that are vertically differentiated (products differ in quality). Thus, we hypothesize that shifts in the nature of competition over time from horizontal differentiation to vertical differentiation account for why the innovator's advantage is not preserved. Imitation timing simply reflects the uncertainty inherent in imitation efforts. One such uncertainty is the extent of product differentiation that the imitator can achieve. We develop several hypotheses that elaborate this basic intuition. We obtained detailed data on innovator‐imitator competition in the branded drug industry to test the hypotheses. All our hypotheses are supported. The main contribution of the article is in showing that the nature of product differentiation in product categories is endogenous to the imitative entry decisions of firms. Copyright © 2008 John Wiley & Sons, Ltd.
Microfluidic Synthesis of Nanomaterials
Authors: Song Yujun , Hormes Josef , Kumar Challa S. S. R.
Published: June 2008

An overview of the current information and analyses on the microfluidic synthesis of different types of nanomaterial, including metallic and silica nanoparticles and quantum dots, is presented. Control of particle size, size distribution, and crystal structure of nanomaterials are examined in terms of the special features of microfluidic reactors.

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Using purposeful messages to educate and reassure parents
Authors: Price Jerry
Published: June 2008

As parents and other family members get more involved with their student's life, student affairs professionals must develop and deliver coherent, purposeful messages about the student experience.
Comparison of gas chromatographic methods for volatile lipid oxidation compounds in soybean oil
Authors: Snyder J. M. , Frankel E. N. , Selke E. , Warner K.
Published: June 2008

To develop new knowledge on undesirable flavors affecting the quality of foods containing polyunsaturated lipids, we investigated the volatiles in soybean oil oxidized at different conditions by three capillary gas chromatographic methods: (a) direct injection (5 min heating at 180 C); (b) static headspace (20 min heating at 180 C, pressurizing for one min), and (c) dynamic headspace (purging 15 min at 180 C onto a porous polymer trap, desorbing from trap for five min). A fused silica column was used with bonded polymethyl and phenyl siloxane phase. At peroxide values between 2 and 10, the major volatile products found in soybean oil by the three methods were pentane, hexanal, 2‐heptenal, 2,4‐heptadienal and 2,4‐decadienal. The intensities of each volatile compound varied with the analytical methods used.
Headspace gas analysis as a measure of rancidity in corn chips
Authors: Robards Kevin , Kerr Amanda F. , Patsalides Emilios , Korth John
Published: June 2008

Headspace analysis by gas chromatography (GC) and gas chromatography‐mass spectrometry (GC‐MS) has been used to identify and quantify volatiles formed in the oxidative deterioration of corn chips. The effect of light and temperature on the formation of propanal, pentanal and hexanal in stored chips was examined and the data correlated with the results of sensory evaluation. The procedure is suitable for determining concentrations of pentanal and hexanal below, one ppm, which is below the level where rancidity based on sensory evaluation is detected. Problems associated with solute partitioning and sample decomposition in the analysis also were investigated.
Fractionation of anhydrous milk fat by short‐path distillation
Authors: Arul Joseph , Boudreau Armand , Makhlouf Joseph , Tardi Rene , Bellavia Tony
Published: June 2008

Anhydrous milk fat was fractionated by short‐path distillation into four fractions at temperatures of 245 and 265 C and pressures of 220 and 100 μm Hg. Two fractions (LF1 and LF2) were liquid, one fraction (IF) was semi‐solid and one fraction (SF) was solid at room temperature. The fractions were characterized by melting temperature profile, solid fat index and triglyceride and fatty acid compositions. The peak melting temperature progressively increased (8.8 to 38.7 C) from liquid to solid fractions. The solid fat content ranged from 0 to 27.5% at 20 C, while native milk fat was 15.4%. The short chain (C24–C34) triglycerides were enriched in the LF1 fraction, long chain (C42–C54) triglycerides were concentrated in the SF fraction, and medium chain (C36–C40) triglycerides in the IF fraction; in the LF2 fraction, though, both short and medium chain triglycerides were enriched. Short chain (C4–C8) fatty acids gradually decreased from liquid to solid fractions and the trend was reverse for long chain (C14–C18) fatty acids, both saturated and unsaturated. The weight average molecular weights and geometric mean‐carbon number of milk fat fractions were in the range of 590.7–782.8 and 31.9–46.3, respectively, compared to 729.3 and 41.0, respectively, for native milk fat, suggesting short‐path distillation effects a very high degree of molecular weight separation.
Phase behavior of some sucrose surfactants with water and n‐decane
Authors: Herrington Thelma M. , Sahi Sarabjit S.
Published: June 2008

The phase behavior of some sucrose esters in water and n‐decane is reported. The type of liquid crystal formed and the extent of a particular phase region are correlated with the hydrocarbon chain length of the fatty acid.
Pnas4 is a novel regulator for convergence and extension during vertebrate gastrulation
Authors: Yao Shaohua , Xie Lifang , Qian Meilin , Yang Hanshuo , Zhou Lang , Zhou Qian , Yan Fei , Gou Lantu , Wei Yuquan , Zhao Xia , Mo Xianming
Published: June 2008

Recent studies show that human Pnas4 might be tumor associated, while its function remains unknown. Here, we investigate the developmental function of Pnas4 using zebrafish as a model system. Knocking down Pnas4 causes gastrulation defects with a shorter and broader axis, as well as a posteriorly mis‐positioned prechordal plate, due to the defective convergence and extension movement. Conversely, over‐expression of Pnas4 mRNA leads to an elongated body axis. We further demonstrate that Pnas4 is required cell‐autonomously for dorsal convergence but not for anterior migration. In addition, genetic interaction assays indicate that Pnas4 might act in parallel with non‐canonical Wnt signal in the regulation of cell movement. Our data suggest that Pnas4 is a key regulator of cell movement during gastrulation.
Snacking patterns among adolescents: a comparison of type, frequency and portion size between Britain in 1997 and Northern Ireland in 2005
Authors: Kerr Maeve A. , Rennie Kirsten L. , McCaffrey Tracy A. , Wallace Julie M. W. , Hannon-Fletcher Mary P. , Livingstone M. Barbara E.
Published: June 2008

Despite the potential link between snack food intake and obesity and the reportedly high prevalence of snacking among adolescents, adolescent snack food patterns (types of foods consumed, frequency and portion size) have not been extensively examined. This study examines these issues using data on the snacking patterns of adolescents aged 13–16 years who took part in the 1997 National Diet and Nutrition Survey (NDNS) and that from a Northern Irish (NI) cohort of adolescents collected 8 years later, in 2005. Overall energy intake was significantly higher in the NI adolescents in 2005 compared with the NDNS adolescents in 1997 (P < 0·01). Consequently, energy intake from snacks was significantly higher in the NI cohort (P < 0·01) and a trend for a higher % energy intake from snacks compared with the NDNS group was observed (median 32·5 % v. 29·8 %, respectively). Sugar-sweetened carbonated and soft drinks remained the most popular choice of snack over this 8-year period; however, both the portion size consumed and frequency of consumption were significantly higher among the adolescents in 2005 compared with those in 1997 (P = 0·022 and P = 0·014, respectively). Despite the lower popularity, and correspondingly lower frequency of milks and beverages, the portion size of both food groups was significantly higher among the adolescents in 2005 compared with those in 1997 (P < 0·001 and P = 0·007, respectively). These findings may provide scope for policy interventions to place particular emphasis on reducing typical portion sizes consumed of popular snack choices, in particular high-energy carbonated and soft drinks, among UK adolescents.
PRUSSIA'S RELATIONS WITH THE HOLY ROMAN EMPIRE, 1740–1786
Authors: WILSON PETER H.
Published: June 2008

Most writers have taken Frederick II at his word and interpreted his sparse and generally derogatory comments about the Holy Roman Empire as indications of its low priority in Prussian policy after 1740. This article offers a reappraisal, based on a re-examination of his writings and his policy towards the Empire and its principal dynasties. Despite his distaste for the imperial constitution, Frederick swiftly appreciated its significance to his goals of security and international recognition. Certainly, relations with the imperial Estates remained secondary to diplomatic and military engagement with Austria and the other major European powers. Nonetheless, the Empire remained more than an arena in which Austro-Prussian rivalry was played out. The imperial constitution offered a means to neutralize threats to Prussia's more vulnerable provinces and a framework to constrain Habsburg ambitions, while ties to minor German dynasties offered avenues to maintain or improve relations with Europe's leading monarchies that were likewise bound within the elite kinship of the Christian old world. For this to be effective, however, Frederick had to engage in all aspects of imperial politics and not just representation in formal institutions.
CULTURE AND COMBAT IN THE WESTERN WORLD, 1900–1945
Authors: WATSON ALEXANDER
Published: June 2008

This article reviews recent research investigating the impact of societal culture on combat performance in the western world during the first half of the twentieth century. It identifies two main strands of historiography. One group of studies has focused on societal culture's influence in shaping the form and functioning of military institutions. A second approach adopted by current scholarship has been to examine societal culture's effect on individual soldiers' resilience and motivation. The article compares and evaluates the results of this research. It concludes that, while sometimes overstressed at other factors' expense, especially combatants' common humanity and the complexity of militaries' own cultures, societal culture has proved to be a subtle yet important influence on martial performance.
Voluntary Unemployment Insurance and Trade Union Membership: Investigating the Connections in Denmark and Sweden
Authors: CLASEN JOCHEN , VIEBROCK ELKE
Published: June 2008

The high rate of trade union membership in Nordic countries is often attributed to the way in which unemployment insurance is organised: that is, as a voluntary scheme which is administered by trade union-linked funds (the so-called Ghent system). However, since trade unions and unemployment insurance funds are formally independent from each other, and alternatives to traditional trade union-linked unemployment funds are available, it is far from clear why the more expensive option of a dual membership in trade union and unemployment insurance is generally favoured. Comparing current characteristics and the operation of the Ghent system in Denmark and Sweden, the article identifies incentives for joining an unemployment insurance fundper seand, secondly, factors which make such a dual membership appealing. It shows that some of these apply to both countries, such as the strong identification with trade unions or the lack of a transparent institutional separation, while others are country-specific, such as job search support in Denmark and access to improved benefit provision in Sweden.
A predictive model for satellite‐derived phytoplankton absorption over the Louisiana shelf hypoxic zone: Effects of nutrients and physical forcing
Authors: Green Rebecca E. , Gould Richard W.
Published: June 2008

We investigated environmental forcing mechanisms of phytoplankton absorption near the Mississippi River delta using multiyear satellite data. An algorithm for the phytoplankton absorption coefficient (aph) was developed from in situ measurements and applied to ocean color imagery. We employed a suite of chemical and physical forcing variables, including surface currents. For satellite‐derived aph time series (2002–2004), correlation and stepwise regression analyses revealed the most important forcing variables of aph on the Louisiana shelf. Areally, Mississippi River discharge and nitrate concentration ([NO3]) were the two most important predictors of aph over the hypoxic zone (defined by its maximum extent). River discharge was important in a band stretching from the Mississippi River delta to the Louisiana‐Texas border. Riverine [NO3] and wind magnitude best predicted aph in nearshore waters, and solar radiation and SST were most important farther offshore over the hypoxic zone, indicating upwelled nutrient sources to phytoplankton. A multiple linear regression model performed well in resolving seasonal and interannual aph variability in model development years (2002–2004) (mean error of 18%, over all pixels and months) and in predicting shelf‐wide aph patterns in 2005 (mean error of 32%). Our results strongly suggest that in recent years, stratification and vertical mixing, in addition to riverine [NO3], play a primary role in regulating phytoplankton biomass over the hypoxic zone. As well, a springtime model experiment showed that aph over the hypoxic zone can differ by an average absolute 37% from its average scenario owing to changes solely in environmental variables other than NO3 flux.
Regional modeling of organic aerosols over China in summertime
Authors: Han Zhiwei , Zhang Renjian , Wang Qin'geng , Wang Wei , Cao Junji , Xu Jun
Published: June 2008

A comprehensive aerosol model was developed and incorporated into a regional air quality model system (RAQMS). It was used to study the behavior and the regional characteristics of carbonaceous aerosols over China in summertime with focus on organic carbon aerosols (OC), especially the secondary organic carbon aerosol (SOC). The whole month of July and August 2003 were selected as simulation period when biogenic volatile organic compounds (VOCs) emitted from vegetation reach the annual maximum. A number of measurements for organic and elemental carbon (EC) aerosols were conducted simultaneously over China during this period, which allow for a rigorous evaluation of model performance and an in‐depth investigation of organic aerosols. The comparison of model results with observations indicates that the developed model system is able to represent the atmospheric oxidative capacity and the major evolutionary features of OC and EC reasonably well, but a tendency was found toward underprediction of both OC and EC aerosols. Sensitivity simulations regarding absorbing matter for condensation (AMC) and enthalpy of vaporization (EOV) were conducted to understand the effects of key factors on secondary organic aerosol (SOA) formation and to provide possible ranges of SOA yields in the troposphere of East Asia. It is found that the overall SOA formation tends to increase with increasing EOV and AMC, but the sensitivity of SOA formation to EOV depends on ambient temperature as well. High OC concentrations mainly occurred in the areas along the Yangtze River, in central China and most parts of north China including Beijing and Tianjin districts, with the maximum monthly mean as high as 15 μg m−3. SOC concentration was high in the forest areas of southeastern, southwestern and northeastern China, with maximum concentration exceeding 5.0 μg m−3 to the south of the Yangtze Delta. The contribution of SOC to OC is around 50% in these areas, whereas in the broad areas north of the Yangtze River, primary organic carbon aerosol (POC) accounts for a high fraction of the total OC (>60%). The estimated regional burdens of EC, OC, POC, and SOC for base case are 28.13, 61.16, 46.05, and 15.11 Gg, respectively. Of the SOC burden, contributions from oxidation of anthropogenic aromatics, monoterpene and isoprene are 17% (2.58 Gg), 48% (7.32 Gg) and 35% (5.21 Gg), respectively. The regional SOC burden varies from 15.1 to 40.3 Gg in different scenarios. For the base case, the total burdens of EC, OC, POC and SOC are estimated to be 13.8, 37.3, 25.6, and 11.8 Gg, respectively, while using emissions solely from China (20°N∼50°N and west of 100°E) in model simulation.
Correlation of substorm injections, auroral modulations, and ground Pi2
Authors: Keiling A. , Angelopoulos V. , Larson D. , Lin R. , McFadden J. , Carlson C. , Bonnell J. W. , Mozer F. S. , Glassmeier K.‐H. , Auster H. U. , Magnes W. , Mende S. , Frey H. , Roux A. , LeContel O. , Frey S. , Phan T. , Donovan E. , Russell C. T. , Mann I. , Liu W. , Li X. , Fillingim M. , Parks G. , Shiokawa K. , Raeder J.
Published: June 2008

In this case study we report a substorm, 23 March 2007, which exhibited oscillations with a period of ∼135 s in three substorm phenomena all of which were one‐to‐one correlated. The in‐situ observations are from one THEMIS spacecraft (8.3 RE geocentric distance) and the geosynchronous LANL‐97A spacecraft. The focus here is on the intensification phase during which THEMIS was conjugate to the region of auroral brightening and its foot point was near the high‐latitude ground station Kiana. The following results will be demonstrated: (1) THEMIS and LANL‐97A (time‐delayed) recorded periodic ion injections (>100 keV). (2) Near‐conjugate high‐latitude ground magnetometer data show very large Pi2 (δH∼150 nT) with a 6‐s time delay compared to the THEMIS ion injections. (3) Low‐latitude ground magnetometer data also show Pi2 with the same waveform as the high‐latitude Pi2 but with longer time delays (20–31 s). (4) Auroral luminosity was periodically modulated during the intensification phase. (5) All three signatures (ion injections, ground Pi2, optical modulation) had the same periodicity of ∼135 s but with various time delays with respect to the THEMIS ion injections. These observations demonstrate that the three substorm phenomena had a common source which controlled the periodicity.
Distantly sampled soils carry few species in common
Authors: Fulthorpe Roberta R , Roesch Luiz FW , Riva Alberto , Triplett Eric W
Published: June 2008

The bacterial phylogenetic structure of soils from four distinctly different sites in South and North America was analyzed. One hundred and thirty-nine thousand sequences of the V9 region of the small subunit of the bacterial ribosomal RNA gene generated for a previous study were used for this work. Whereas the previous work estimated levels of species richness, this study details the degree of bacterial community overlap between the four soils. Sequences from the four soils were classified and grouped into different phyla and then assigned to operational taxonomic units (OTUs) as defined by 97 or 100% sequence similarity. Pairwise Jaccard and θ similarity indices averaged over all phyla equalled 6 and 12% respectively at the 97% similarity level, and 15% for both at the 100% similarity level. At 100 and 97% sequence similarity, 1.5 and 4.1% of OTUs were found in all four soils respectively, and 87.9 and 74.4%, respectively were a unique particular soil. These analyses, based on the largest soil bacterial sequence retrieval to date, establish the high degree of community structure difference for randomly sampled dissimilar soils and support the idea that wide sampling is important for bioprospecting. The 10 most abundant cultured genera were determined in each soil. These 10 genera comprised a significant proportion of the reads obtained from each soil (31.3–37.4%). Chitinophaga was the most abundant or the second most abundant genus in all four soils with 7.5–13.8% of the total bacterial sequences in these soils. The striking result is that several culturable genera, whose roles in soil are virtually unknown, were found among these dominant sequences.
A‐FABP—A Biomarker Associated With the Metabolic Syndrome and/or an Indicator of Weight Change?
Authors: Engl Julia , Ciardi Christian , Tatarczyk Tobias , Kaser Susanne , Laimer Markus , Laimer Elisabeth , Weiss Helmut , Aigner Franz , Molnar Clemens , Tilg Herbert , Patsch Josef R. , Ebenbichler Christoph F.
Published: June 2008

Objective: Adipocyte fatty acid‐binding protein (A‐FABP) is a plasma biomarker recently associated with the metabolic syndrome. The aim of these studies was to investigate changes of A‐FABP during profound weight loss induced by laparoscopic adjustable gastric banding (LAGB).

Methods and Procedures: In study one, 29 severely obese female subjects were examined before and 1 year after surgical treatment. A subgroup of 10 patients was investigated in 3‐month intervals. Metabolic parameters were determined using standard methods, and A‐FABP was detected using a commercially available enzyme‐linked immunosorbent assay.

Results: Mean weight loss after 1 year was 24.9 kg (P < 0.001), mainly due to a decrease in fat mass. Metabolic parameters improved substantially. However, serum A‐FABP remained stable. In study two, a subgroup of 10 patients was examined quarterly to determine the time course of A‐FABP changes. Quarterly measurements of serum A‐FABP were significantly higher than baseline levels with the highest A‐FABP value after the first 3 months, where patients had highest weight loss.

Discussion: Our results in study one show that A‐FABP serum levels are positively associated with body weight and fat mass. However, 1 year after pronounced weight loss A‐FABP levels remained unchanged. In study two, time course analyses revealed maximum increase of serum A‐FABP in parallel to highest weight loss, which allows to suppose that A‐FABP is not only a biomarker of the metabolic syndrome in the steady state, but also a marker of weight changes in dynamic situations.
The Association of Pericardial Fat With Calcified Coronary Plaque
Authors: Ding Jingzhong , Kritchevsky Stephen B. , Harris Tamara B. , Burke Gregory L. , Detrano Robert C. , Szklo Moyses , Carr J. Jeffrey ,   Multi‐Ethnic Study of Atherosclerosis
Published: June 2008

Background: Pericardial fat has a higher secretion of inflammatory cytokines than subcutaneous fat. Cytokines released from pericardial fat around coronary arteries may act locally on the adjacent cells.

Objective: We examined the relationship between pericardial fat and calcified coronary plaque.

Methods and Procedures: Participants in the community‐based Multi‐Ethnic Study of Atherosclerosis (MESA) underwent a computed tomography (CT) scan for the assessment of calcified coronary plaque in 2000/2002. We measured the volume of pericardial fat using these scans in 159 whites and blacks without symptomatic coronary heart disease from Forsyth County, NC, aged 55–74 years.

Results: Calcified coronary plaque was observed in 91 participants (57%). After adjusting for height, a 1 s.d. increment in pericardial fat was associated with an increased odds of calcified coronary plaque (odds ratio (95% confidence interval): 1.92 (1.27, 2.90)). With further adjustment of other cardiovascular factors, pericardial fat was still significantly associated with calcified coronary plaque. This relationship did not differ by gender and ethnicity. On the other hand, BMI and height‐adjusted waist circumference were not associated with calcified coronary plaque.

Discussion: Pericardial fat is independently associated with calcified coronary plaque.
Validity of Physical Activity Intensity Predictions by ActiGraph, Actical, and RT3 Accelerometers
Authors: Rothney Megan P. , Schaefer Emily V. , Neumann Megan M. , Choi Leena , Chen Kong Y.
Published: June 2008

Objective: Accelerometers are promising tools for characterizing physical activity (PA) patterns in free‐living persons. To date, validation of energy expenditure (EE) predictions from accelerometers has been restricted to short laboratory or simulated free‐living protocols. This study seeks to determine the capabilities of eight previously published regression equations for three commercially available accelerometers to predict summary measures of daily EE.

Methods and Procedures: Study participants were outfitted with ActiGraph, Actical, and RT3 accelerometers, while measurements were simultaneously made during overnight stays in a room calorimeter, which provided minute‐by‐minute EE measurements, in a diverse subject population (n = 85). Regression equations for each device were used to predict the minute‐by‐minute metabolic equivalents (METs) along with the daily PA level (PAL).

Results: Two RT3 regressions and one ActiGraph regression were not significantly different from calorimeter measured PAL. When data from the entire visit were divided into four intensity categories—sedentary, light, moderate, and vigorous—significant (P < 0.001) over‐ and underpredictions were detected in numerous regression equations and intensity categories.

Discussion: Most EE prediction equations showed differences of <2% in the moderate and vigorous intensity categories. These differences, though small in magnitude, may limit the ability of these regressions to accurately characterize whether specific PA goals have been met in the field setting. New regression equations should be developed if more accurate prediction of the daily PAL or higher precision in determining the time spent in specific PA intensity categories is desired.
Use of an Operant Task to Estimate Food Reinforcement in Adult Humans With and Without BED
Authors: Nasser Jennifer A. , Evans Suzette M. , Geliebter Allan , Pi‐Sunyer F. Xavier , Foltin Richard W.
Published: June 2008

Objective: The purpose of this study was to demonstrate the utility of food‐reinforced operant task performance in modeling binge‐eating disorder (BED). We hypothesized that food reinforcement after a caloric preload would be related to BED status, but not hunger.

Methods and Procedures: We investigated the association between reports of hunger, binge tendency, and food reinforcement in a sample of 18 women (12 non‐BED, 7 lean, 5 obese, and 6 obese BED). Participants completed two sessions of operant task performance after consuming 600 ml of flavored water or 600 ml of a 1 kcal/ml liquid meal.

Results: Under the water condition, food reinforcement did not differ between the non‐BED and BED groups, and was positively correlated with hunger ratings across all participants (r = 0.55, P = 0.023). Under the liquid meal condition, food reinforcement was significantly decreased compared with the water condition in the non‐BED group (t = −2.6, P = 0.026). There was also a significant difference between the non‐BED and BED groups in the fed condition (41 ± 40, 117 ± 60, F = 10.3, P = 0.005, non‐BED vs. BED, respectively, mean ± s.d.). The correlation between food reinforcement and hunger remained significant only in the non‐BED group (r = 0.69, P = 0.011).

Discussion: Our results support the hypothesis that food reinforcement measured after a caloric preload is related to BED status but not hunger in those subjects with BED. The data also suggest that operant task performance can be useful in modeling BED criteria such as “eating when not physically hungry.”
Fueling the Obesity Epidemic? Artificially Sweetened Beverage Use and Long‐term Weight Gain
Authors: Fowler Sharon P. , Williams Ken , Resendez Roy G. , Hunt Kelly J. , Hazuda Helen P. , Stern Michael P.
Published: June 2008

We have examined the relationship between artificially sweetened beverage (ASB) consumption and long‐term weight gain in the San Antonio Heart Study. From 1979 to 1988, height, weight, and ASB consumption were measured among 5,158 adult residents of San Antonio, Texas. Seven to eight years later, 3,682 participants (74% of survivors) were re‐examined. Outcome measures were incidence of overweight/obesity (OW/OBinc) and obesity (OBinc) (BMI ≥ 25 and ≥ 30 kg/m2, respectively), and BMI change by follow‐up (ΔBMI, kg/m2). A significant positive dose‐response relationship emerged between baseline ASB consumption and all outcome measures, adjusted for baseline BMI and demographic/behavioral characteristics. Consuming >21 ASBs/week (vs. none) was associated with almost‐doubled risk of OW/OB (odds ratio (OR) = 1.93, P = 0.007) among 1,250 baseline normal‐weight (NW) individuals, and doubled risk of obesity (OR = 2.03, P = 0.0005) among 2,571 individuals with baseline BMIs <30 kg/m2. Compared with nonusers (+1.01 kg/m2), ΔBMIs were significantly higher for ASB quartiles 2–4: +1.46 (P = 0.003), +1.50 (P = 0.002), and +1.78 kg/m2 (P < 0.0001), respectively. Overall, adjusted ΔBMIs were 47% greater among artificial sweetner (AS) users than nonusers (+1.48 kg/m2 vs. +1.01 kg/m2, respectively, P < 0.0001). In separate analyses—stratified by gender; ethnicity; baseline weight category, dieting, or diabetes status; or exercise‐change category—ΔBMIs were consistently greater among AS users. These differences, though not significant among exercise increasers, or those with baseline diabetes or BMI >30 kg/m2 (P = 0.069), were significant in all 13 remaining strata. These findings raise the question whether AS use might be fueling—rather than fighting—our escalating obesity epidemic.
Two spheres in a free stream of a second-order fluid
Authors: Ardekani A. M. , Rangel R. H. , Joseph D. D.
Published: June 2008

The forces acting on two fixed spheres in a second-order uniform flow are investigated. When α1+α2=0, where α1 and α2 are fluid parameters related to the first and second normal stress coefficients, the velocity field for a second-order fluid is the same as the one predicted by the Stokes equations while the pressure is modified. The Stokes solutions given by Stimson and Jeffery [Proc. R. Soc. London, Ser. A 111, 110 (1926)] for the case when the flow direction is along the line of centers and Goldman et al. [Chem. Eng. Sci. 21, 1151 (1966)] for the case when the flow direction is perpendicular to the line of centers are utilized and the stresses and the forces acting on the particles in a second-order fluid are calculated. For flow along the line of centers or perpendicular to it, the net force is in the direction that tends to decrease the particle separation distance. For the case of flow at arbitrary angle, unequal forces are applied to the spheres perpendicularly to the line of centers. These forces result in a change of orientation of the sedimenting spheres until the line of centers aligns with the flow direction. In addition, the potential flow of a second-order fluid past two fixed spheres in a uniform flow is investigated. The normal stress at the surface of each sphere is calculated and the viscoelastic effects on the normal stress for different separation distances are analyzed. The contribution of the potential flow of a second-order fluid to the force applied to the particles is an attractive force. Our explanations of the aggregation of particles in viscoelastic fluids rest on three pillars; the first is a viscoelastic “pressure” generated by normal stresses due to shear. Second, the total time derivative of the pressure is an important factor in the forces applied to moving particles. The third is associated with a change in the normal stress at points of stagnation which is a purely extensional effect unrelated to shearing.
Simultaneous measurement of magnetization and magnetostriction in 50T pulsed high magnetic fields
Authors: Doerr M. , Lorenz W. , Neupert T. , Loewenhaupt M. , Kozlova N. V. , Freudenberger J. , Bartkowiak M. , Kampert E. , Rotter M.
Published: June 2008

To simultaneously perform magnetization and magnetostriction measurements in high magnetic fields, a miniaturized device was developed that combines an inductive magnetometer with a capacitive dilatometer and, therefore, it is called “dilamagmeter.” This combination of magnetic and magnetoelastic investigations is a new step to a complex understanding of solid state properties. The whole system can be mounted in a 12mm clear bore of any cryostat usually used in nondestructive pulsed high field magnets. The sensitivity of both methods is about 10−5Am2 for magnetization and 10−5 relative changes in length for striction measurements. Measurements on a GdSi single crystal, which are corrected by the background signal of the experimental setup, agree well with the results of steady field experiments. All test measurements, which are up until now performed in the temperature range of 4–100K, confirm the perfect usability and high stability in pulsed fields up to 50T with a pulse duration of 10ms.
Atomic assembly during ion-beam assisted growth: Kinetic modeling
Authors: Trushin Yu. V. , Kulikov D. V. , Safonov K. L. , Gerlach J. W. , Höche Th. , Rauschenbach B.
Published: June 2008

The influence of an additional bombardment with low-energy ions during conventional molecular beam epitaxy deposition is studied. A model is proposed describing the initial growth stages during conventional molecular beam epitaxy and ion-beam assisted molecular beam epitaxy. The additional bombardment with low-energy ions leads to a transformation of the growth mode from island growth to layer-by-layer growth. In the first stages of film growth, the hyperthermal ion bombardment causes an increasing detachment of atoms from the tops of the growing islands. Based on the model, using simulation by the kinetic-equation method, the size distribution function of growing clusters is calculated. The theoretical results are in good agreement with experimental results obtained upon the deposition of GaN films.
Signal restoration from atmospheric degradation in terahertz spectroscopy
Authors: Kong Seong G. , Wu Dong H.
Published: June 2008

This paper presents a method of restoring signals in terahertz spectroscopy by removing the distortion from the observed terahertz signals. The distortion is generated by the absorption and scattering of gas molecules and water vapor in the atmosphere during the transmission of terahertz beams through the air from the source to the spectrometer. Such atmospheric degradation causes spurious spectral dips and peaks in the terahertz spectrum, which often obscure the spectral peaks specific to the material of interest. This fact makes it challenging to measure the terahertz spectroscopic signatures of objects in a humid air environment, even at a short distance of approximately 1 m. A terahertz signal restoration filter based on a nonlinear artificial neural network model effectively removes noisy absorption peaks in terahertz spectra caused by atmospheric degradation.
Hydrogen atoms in solid xenon: Trapping site structure, distribution, and stability as revealed by EPR studies in monoisotopic and isotopically enriched xenon matrices
Authors: Feldman Vladimir I. , Sukhov Fedor F. , Orlov Aleksei Yu.
Published: June 2008

Trapping and decay of hydrogen atoms generated by fast electron irradiation of solid xenon doped with small hydrogen-containing molecules (acetylene, water) were studied by EPR using monoisotopic Xe136 matrix (I=0) and highly isotopically enriched Xe129 matrix (I=12). It was found that more than 99% of H atoms observed by EPR are initially trapped in the octahedral interstitial trapping sites, whereas initial population of the substitutional traping sites is very small (less than 1%). The Xe129 hyperfine coupling tensor parameters for major trapping site were determined from direct measurements in a Xe136 matrix doped with small amount of Xe129: A0 (Xe129)=−92.1MHz and B(Xe129)=−22MHz. Final proof for the trapping site structure was obtained from comparison between experiment and simulation for the highly enriched Xe129 matrix. The mean interspin distance of approximately 4nm was estimated from the EPR signal linewidth in a Xe136 matrix, the hydrogen atom loss upon irradiation being negligible at low doses. Decay of trapped H atoms occurring at 38–45K leads to population (or creation) of metastable traps of lower symmetry.
Studies on the growth of pure double-walled carbon nanotube and its phonon spectra
Authors: Murakami Toshiya , Matsumoto Kazuyo , Kisoda Kenji , Naito Ryoji , Nishio Koji , Isshiki Toshiyuki , Harima Hiroshi
Published: June 2008

Double-walled carbon nanotubes (DWCNTs) with a purity higher than 99% were synthesized by chemical vapor deposition, and their Raman spectra were observed at different excitation wavelengths λex. The spectra had a unique feature compared with single-walled carbon nanotubes (SWCNTs): the G-band shape was distinctly different from that of SWCNTs and showed a clear λex dependence. The pure DWCNT samples showed complex radial breathing modes (RBM) spectra. The mode peaks were unambiguously classified into those for the inner and outer tubes by applying a simple analytic model considering the interwall interaction. After isolation treatment of the pure bundled samples, we observed RBM signals of DWCNTs having an identical inner tube with different outer tubes. The peculiar behavior of the G-band shape was interpreted by resonance enhancement of the outer tube.
Invariants from classical field theory
Authors: Díaz Rafael , Leal Lorenzo
Published: June 2008

We introduce a method that generates invariant functions from perturbative classical field theories depending on external parameters. By applying our methods to several field theories such as Abelian BF, Chern–Simons, and two-dimensional Yang–Mills theory, we obtain, respectively, the linking number for embedded submanifolds in compact varieties, the Gauss’ and the second Milnor’s invariant for links in S3, and invariants under area-preserving diffeomorphisms for configurations of immersed planar curves.
Stimulated emission from trap electronic states in oxide of nanocrystal Si
Authors: Huang Wei-Qi , Jin Fen , Wang Hai-Xu , Xu Li , Wu Ke-Yue , Liu Shi-Rong , Qin Cao-Jian
Published: June 2008

We have demonstrated a stimulated photoluminescence (PL) at 694 and 692nm whose emission peak has a Lorentzian shape with a full width at half maximum of 0.5–0.6nm. This stimulated emission comes from the nanostructures on porous silicon oxidized fabricated by irradiation and annealing treatment. Controlling the time of annealing can produce a good coherent emission. A model has been proposed for explaining the stimulated emission in which the trap states of the interface between oxide of silicon and porous nanocrystal play an important role. Calculation shows that trap electronic states appear in the energy gap of the smaller nanocrystal when SiO bonds or Si–O–Si bonds are formed. In the theoretical model, the most important factor in the enhancement and pinning effect of PL emission is the relative position between the level of the trap states and the level of the photoexcitation in the silicon nanocrystal.