bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of total antioxidant capacity from diet and supplements in US adults
Authors: Yang Meng , Chung Sang-Jin , Chung Chin Eun , Kim Dae-Ok , Song Won O. , Koo Sung I. , Chun Ock K.
Published: February 2011

Given the importance of dietary antioxidants in reducing the risks of chronic diseases, the present study aimed to estimate the intake of total antioxidant capacity (TAC) from diet and dietary supplements of US adults. We utilised the US Department of Agriculture flavonoid and proanthocyanidin databases, dietary supplement data and food consumption data of 4391 US adults aged 19+ years in the National Health and Nutrition Examination Survey 2001–2. In order to convert the intake data of individual antioxidant compounds to TAC values, the vitamin C equivalent (VCE) of forty-three antioxidant nutrients measured previously was also applied. Daily TAC averaged 503·3 mg VCE/d (approximately 75 % from diet and 25 % from supplements). The energy-adjusted daily TAC level from diet and supplements was higher in women (except for carotenoids), older adults, Caucasian (except for carotenoids), non-alcohol consumers (for vitamin E and proanthocyanidins), subjects with higher income (except for carotenoids) and higher exercise levels than their counterparts (P < 0·05). TAC was positively associated with daily consumption of fruits and fruit juices, vegetables and vegetable products, beverages, wines and teas (P < 0·001). Teas, dietary supplements, and fruits and fruit juices were the major sources of dietary TAC of the US population (28, 25 and 17 %, respectively), while the contribution of vegetables and vegetable products to TAC was minimal ( < 2 %). The present study indicates that antioxidant intake from various diet and supplements contributes to TAC status. TAC levels are different in sociodemographic subgroups of the US population. The relationship between TAC intake and risks of chronic disease warrants further investigation.
Insecticide use and competition shape the genetic diversity of the aphid Aphis gossypii in a cotton-growing landscape
Authors: Brévault T. , Carletto J. , Tribot J. , Vanlerberghe-Masutti F.
Published: February 2011

Field populations of the cotton aphid, Aphis gossypii Glover, are structured into geographically widespread host races. In the cotton-producing regions of West and Central Africa (WCA), two genotypes have been repeatedly detected within the cotton host race, one of which (Burk1) is prevalent (>90%) and resistant to several insecticides, as opposed to the second one (Ivo). Here, we conducted whole plant and field cage experiments to test hypotheses for such low genetic diversity, including selection from insecticide treatments, interclonal competition and adaptation to host plant, or climatic conditions. To assess the genetic diversity of immigrant aphids, alatae were trapped and collected on cotton and relay host plants (okra and roselle) in the early cropping season. Individuals were genotyped at eight specific microsatellite loci and characterized by a multilocus genotype (MLG). When independently transferred from cotton (Gossypium hirustum L.) leaf discs to whole plants (G. hirsutum and G. arboreum, roselle and okra), Ivo and Burk1 performed equally well. When concurrently transferred from cotton leaf discs to the same plant species, Ivo performed better than Burk1, indicating that competition favoured Ivo. This was also the case on G. hirsutum growing outdoors. Conversely, Burk1 prevailed when cotton plants were sprayed with insecticides. In experiments where aphids were allowed to move to neighbouring plants, Burk1 was better represented than Ivo on low-populated plants, suggesting that dispersal may be a way to avoid competition on crowded plants. Most cotton aphids collected on cotton or relay host plants in the early cropping season were Burk1 (>90%), indicating high dispersal ability and, probably reflecting high frequency on host plants from which they dispersed. In the agricultural landscape of WCA, the use of broad-range insecticides on both cotton and relay host plants has led to the prevalence of one genotype of A. gossypii resistant to different classes of insecticides. Deployment of widespread and integrated pest management strategies are needed to restore cotton aphid control.
Investigation of the genetic diversity of an invasive whitefly (Bemisia tabaci) in China using both mitochondrial and nuclear DNA markers
Authors: Chu D. , Gao C.S. , De Barro P. , Wan F.H. , Zhang Y.J.
Published: February 2011

It is often considered that reduced genetic variation due to bottlenecks and founder effects limits the capacity for species to establish in new environments and subsequently spread. The recent invasion (during the past five years) of an alien whitefly, one member ofBemisia tabacicryptic species complex, referred to as Mediterranean (herein referred to as Q-type) in Shandong Province, China, provides an ideal opportunity to study the changes in genetic variation between its home range in the Mediterranean region and its invasion range. Using both the mitochondrial cytochrome oxidase I (mtCOI) and nuclear (microsatellite) DNA, we show that Q in Shandong likely originated in the western Mediterranean. We also found that the haplotype diversity was low compared with its presumed geographic origin, whereas microsatellite allele diversity showed no such decline. A key factor in invasions is the establishment of females and so bottleneck and founder events can lead to a very rapid and considerable loss of mitochondrial diversity. The lack of haplotype diversity in Shandong supports the interpretation that, at one or more points between the western Mediterranean and China, the invading Q lost haplotype diversity, most probably through the serial process of establishment and redistribution through trade in ornamental plants. However, the loss in haplotype diversity does not necessarily mean that nuclear allelic diversity should also decline. Provided females can mate freely with whichever males are available, allelic diversity can be maintained or even increased relative to the origin of the invader. Our findings may offer some explanation to the apparent paradox between the concept of reduced genetic variation limiting adaptation to new environments and the observed low diversity in successful invaders.
Analysts’ Incentives to Produce Industry-Level versus Firm-Specific Information
Authors: Liu Mark H.
Published: February 2011

Using stock returns around recommendation changes to measure the information produced by analysts, I find that analysts produce more firm-specific than industry-level information. Analysts produce more firm-specific information on stocks with higher idiosyncratic return volatilities. The amount of industry information produced by analysts increases with the absolute value of the stock’s industry beta and decreases with the stock’s idiosyncratic volatility. Other stocks in the industry also respond to the recommendation change, and the magnitude of the response increases with the absolute value of the industry beta of the recommended stock and that of other stocks in the industry. I also offer results on how investors may use analyst research more effectively and potentially improve their investment performance.
Liquidity and Arbitrage in the Market for Credit Risk
Authors: Nashikkar Amrut , Subrahmanyam Marti G. , Mahanti Sriketan
Published: February 2011

The recent credit crisis has highlighted the importance of market liquidity and its interaction with the price of credit risk. We investigate this interaction by relating the liquidity of corporate bonds to the basis between the credit default swap (CDS) spread of the issuer and the par-equivalent bond yield spread. The liquidity of a bond is measured using a recently developed measure called latent liquidity, which is defined as the weighted average turnover of funds holding the bond, where the weights are their fractional holdings of the bond. We find that bonds with higher latent liquidity are more expensive relative to their CDS contracts after controlling for other realized measures of liquidity. Analysis of interaction effects shows that highly illiquid bonds of firms with a greater degree of uncertainty are also expensive, consistent with limits to arbitrage between CDS and bond markets, due to the higher costs of “shorting” illiquid bonds. Additionally, we document the positive effects of liquidity in the CDS market on the CDS-bond basis. We also find that several firm- and bond-level variables related to credit risk affect the basis, indicating that the CDS spread does not fully capture the credit risk of the bond.
Introduction: Interviews vs. ‘natural’ contexts: A false dilemma
Authors: De Fina Anna , Perrino Sabina
Published: February 2011

The popularity of interviewing as a method of data collection in the social sciences is a recognized fact. In their survey of qualitative research paradigms and methods, Denzin and Lincoln (2004:353) declare that “the interview is the favorite methodological tool of the qualitative researcher.” And, describing data-collection techniques in sociolinguistics and dialectology, Fuller (2000:388) argues that “much of the data in the field comes from interviews.” These assertions are hardly surprising given the central role that interviews have assumed as an essential part of the toolkit of the qualitative researcher since the early decades of the twentieth century (Fontana & Frei 2004). Interviews are the most common cross-disciplinary research instruments since they are widely used by investigators in fields as diverse as education, anthropology, sociology, social psychology, and social history, where they serve as vital research methods alone or in combination with other techniques such as participant observation. Given the centrality of interpretive and qualitative research paradigms in sociolinguistics, ethnography, linguistic anthropology, and narrative studies, the interview has acquired an even more prominent place for investigation in these disciplines. However, this research method and tool for collecting data has been the object of extremes of confidence and criticism. On one side there are those who try to erase the interactional context of the interview, believing that it is both possible and desirable to make participants forget about the event so that interviewers can access their “natural” behavior. On the opposite side there are those who argue that interviews are “inauthentic” and “artificial” contexts for data collection and therefore it is best to avoid them completely. In both extremes, the interview ends up being a problem to overcome. One unfortunate result of these attitudes has been that the interview as a real communicative event has been understudied. Our objective with this special issue is to contribute to redressing this tendency by drawing attention to the need for, and advantages of, the research interview as a legitimate interactional encounter, and taking narrative as our focus. In doing this we build on a small but significant cross-disciplinary body of mostly recent scholarship that has analyzed a variety of issues related to the use of semi-structured and open-ended interviews in qualitative research, and that has recognized the crucial importance of placing interview data in context.
Stance, positioning, and alignment in narratives of professional experience
Authors: Baynham Mike
Published: February 2011

This article examines narratives of professional experience in a corpus of forty interviews in which English to Speakers of Other Languages (ESOL) teachers reflect on their professional life histories as well as their current teaching. The notion of “stance” emerged as a major theme: the teachers positioned themselves in relation to the policy environment, to learners, teaching and learning, and their sense of control in their working lives. Narrative was an important discursive resource for doing so and a range of narrative types (personal, generic/iterative, hypothetical, exemplum, and ‘negated’) are identified, each demonstrating performance features. Using Dubois's (2007) definition of stance, I examine the dynamic relationship between stance taking and discursive positioning, discussing the role of performance in these processes. Shifts into performance are shown to depend on participant roles and alignments in the interviews rather than on particular narrative types. Thus, the data contradicts some of Wolfson's (1976) observations on narratives in the research interview. The analysis contributes to our understanding of the research interview as a dynamically co-constructed speech genre rather than as a neutral locus for gathering data. (Professional narrative, performance, stance, alignment, positioning)
Hospital-acquired infections in Belgian acute-care hospitals: an estimation of their global impact on mortality, length of stay and healthcare costs
Authors: VRIJENS F. , HULSTAERT F. , DEVRIESE S. , VAN DE SANDE S.
Published: February 2011

Assessing the overall burden of disease which can be attributed to hospital-acquired infections (HAIs) remains a challenge. A matched cohort study was performed to estimate excess mortality, length of stay and costs attributable to HAIs in Belgian acute-care hospitals, using six matching factors (hospital, diagnosis-related group, age, ward, Charlson score, estimated length of stay prior to infection). Information was combined from different sources on the epidemiology and burden of HAIs to estimate the impact at national level. The total number of patients affected by a HAI each year was 125 000 (per 10·9 million inhabitants). The excess mortality was 2·8% and excess length of stay was 7·3 days, corresponding to a public healthcare cost of €290 million. A large burden was observed outside the intensive-care unit setting (87% of patients infected and extra costs, 73% of excess deaths).
Associations between dairy consumption and body weight: a review of the evidence and underlying mechanisms
Authors: Dougkas Anestis , Reynolds Christopher K. , Givens Ian D. , Elwood Peter C. , Minihane Anne M.
Published: February 2011

As the incidence of obesity is reaching ‘epidemic’ proportions, there is currently widespread interest in the impact of dietary components on body-weight and food intake regulation. The majority of data available from both epidemiological and intervention studies provide evidence of a negative but modest association between milk and dairy product consumption and BMI and other measures of adiposity, with indications that higher intakes result in increased weight loss and lean tissue maintenance during energy restriction. The purported physiological and molecular mechanisms underlying the impact of dairy constituents on adiposity are incompletely understood but may include effects on lipolysis, lipogeneis and fatty acid absorption. Furthermore, accumulating evidence indicates an impact of dairy constituents, in particular whey protein derivatives, on appetite regulation and food intake. The present review summarises available data and provides an insight into the likely contribution of dairy foods to strategies aimed at appetite regulation, weight loss or the prevention of weight gain.
Ruminant and industrial sources of trans-fat and cardiovascular and diabetic diseases
Authors: Tardy Anne-Laure , Morio Béatrice , Chardigny Jean-Michel , Malpuech-Brugère Corinne
Published: February 2011

The various positional isomers of oleic acid (18 : 1Δ9c or 9c-18 : 1) may have distinct biological effects. Detrimental effects of consumption of industrial trans-fatty acids (TFA) (elaidic acid; 18 : 1Δ9t) from partially hydrogenated vegetable oils on CVD risk factors are well documented. In addition, epidemiological data suggest that chronic consumption of industrial sources of TFA could alter insulin sensitivity and predispose for type 2 diabetes. However, intervention studies on this issue have remained inconclusive. Moreover, very little information is available on the effect of natural sources of TFA (vaccenic acid; 18 : 1Δ11t) coming from dairy products and ruminant meat on the development of CVD and type 2 diabetes. The review focuses on the impact of the consumption of ruminant TFA in relation to cardiovascular risk factors, inflammation and type 2 diabetes.
Spatial Bias and Right Hemisphere Function: Sex-Specific Changes with Aging
Authors: Chen Peii , Goedert Kelly M. , Murray Elizabeth , Kelly Karen , Ahmeti Shpresa , Barrett Anna M.
Published: February 2011

Patterns of cerebral asymmetry related to visuospatial functions may change with age. The typical leftward bias on a line bisection task may reflect cerebral asymmetry. With age, such leftward bias decreases. This study demonstrated that the age-related decrease of leftward bias may actually be sex-specific. In addition, previous research suggests that young adults’ deviation in line bisection may reflect asymmetric hemispheric activation of perceptual–attentional “where” spatial systems, rather than motor-intentional “aiming” spatial systems; thus, we specifically fractionated “where” and “aiming” bias of men and women ranging in age from 22 to 93 years old. We observed that older men produced greater rightward line bisection errors, of primarily “where” spatial character. However, women's errors remained leftward biased, and did not significantly change with age. “Where” spatial systems may be linked to cortico-cortical processing networks involving the posterior part of the dorsal visuospatial processing stream. Thus, the current results are consistent with the conclusion that reduced right dorsal spatial activity in aging may occur in the male, but not female, adult spatial system development. (JINS, 2011, 17, 455–462)
Profiling alternative food system supporters: The personal and social basis of local and organic food support
Authors: Bean Molly , Sharp Jeff S.
Published: February 2011

Consumers appear increasingly interested in how to engage in consumptive practices that lead to a more sustainable food and agricultural system. In this paper, we examine two possible consumptive pathways for achieving sustainability: the purchase of organic foods and/or the purchase of local foods. While there is some debate regarding the integrity and sustainability of organic versus locally produced foods, there is limited information examining the similarities or differences among consumers variably interested in one or the other attribute. Using data from a statewide survey of Ohio, USA, respondents and members of a food cooperative and an environmental and social responsibility organization, a typology is proposed and comparisons are made among different types of local and organic food consumers regarding their attitudes about food, agriculture and the environment. While a large proportion of the survey respondents expressed little or only modest interest in either local or organic foods, distinct groups of respondents interested in primarily the local attribute, primarily the organic attribute, and both attributes are identified. The results reveal similarities and differences across types with the profiles of each type of consumer contributing to a more nuanced view of supporters of these foods that can assist in production decisions, as well as purchasing and marketing decisions among retailers.
A Model of Values-Based Shared Leadership and Sustainable Performance
Authors: Manz Charles C. , Manz Karen P. , Adams Stephen B. , Shipper Frank
Published: February 2011

This short note presents a theoretical model of the relationship between performance and values-based shared leadership. Preliminary support for the model is provided in the form of critical incident examples that were derived from an ethnographic inductive model building study of Herman Miller Inc., a leading business furniture innovator and manufacturer. The model adds to the shared leadership literature by examining the relationship of shared leadership with sustainable performance as moderated by two primary values: (1) commitment to an ongoing creative process and (2) the recognition of every organization stakeholder as a valuable resource.
Shared Leadership and Team Performance in a Business Strategy Simulation
Authors: Boies Kathleen , Lvina Elena , Martens Martin L.
Published: February 2011

This study examined the relations between shared leadership in teams, team trust, potency, and performance. Forty-nine teams participating in a business simulation game rated their team potency, trust, and team leadership styles. Team potency and trust were positively related to shared transformational leadership and negatively related to passive avoidant leadership, but only the latter was significantly negatively related to team performance in the business strategy simulation. These results suggest that teams might not always benefit from transformational leadership qualities, but that “negative” leadership styles might be detrimental to performance and to the trust and confidence in the team.
Promoting Work Motivation in Organizations
Authors: Wegge Jürgen , Jeppesen Hans Jeppe , Weber Wolfgang G. , Pearce Craig L. , Silva Silvia A. , Pundt Alexander , Jonsson Thomas , Wolf Sandra , Wassenaar Christina L. , Unterrainer Christine , Piecha Annika
Published: February 2011

What are the best interventions that Work and Organizational Psychology offers today for promoting high work motivation in organizations? This paper seeks to answer this question in two steps. First, we briefly summarize the main findings from 26 meta-analyses concerned with traditional practices such as goal setting, feedback, work design, financial incentives, or training. These practices can improve both organizational performance and the well-being of organizational members. Second, we examine in more depth a new, increasingly important high performance work practice: Employee involvement in organizational leadership (EIOL). This approach is built on theories focusing on organizational participation, shared leadership, and organizational democracy. We also illustrate recently constructed measurement instruments for assessing these constructs. This synopsis leads us to the development of a new integrative, multilevel model of EIOL. The model includes several mediator (e.g., knowledge exchange) and moderator variables (e.g., self-leadership competencies of actors) that explain why and when this approach is effective. We conclude that future research should focus on cross-level interactions of different forms of organizational participation, shared leadership, and organizational democracy, and seek to identify the processes mediating their interplay.
Hyporheic flow path response to hydraulic jumps at river steps: Hydrostatic model simulations
Authors: Endreny T. , Lautz L. , Siegel D.
Published: February 2011

This research examined hydrostatic groundwater model (MODFLOW) predictive adequacy and sensitivity in simulating hyporheic flow paths across a river step with a hydraulic jump. In a companion paper, we used flume and hydrodynamic model analysis to develop a refined conceptual model depicting these flow paths with zones of downwelling and upstream‐directed flux below the step. The previous coarse conceptual model predicted uniform downstream‐directed upwelling below the step. The hydrostatic model accurately predicted the downwelling and upstream‐directed fluxes beneath the wave and jump but failed to predict the plunge pool downwelling, which is driven by dynamic pressures. Sensitivity tests varied riverbed topography and water surface profile geometry for a river with 1% slopes, 10 cm flow depths, and 50–150 cm long jets and jumps. The flow paths below the jet‐jump region were driven by hydrostatic pressures and were highly sensitive to water surface profile and riverbed topography parameters. Failure to simulate the hydraulic jump caused errors in hyporheic flow path predictions beneath the jump region (∼1 m long by ∼0.5 m deep). If the jump was poorly parameterized, several meters of riverbed flow paths could be erroneously modeled as pointing upstream. The hyporheic zone may contain a spatial mosaic of aerobic and anaerobic waters regulating nutrient transformations and biologic productivity. Accurate parameterization of hydraulic jumps in hyporheic simulation has the potential to improve predictions and explain heterogeneous subsurface flow paths and associated nutrient patterns and ecosystem functions.
Dynamics of fluid mixtures in nanospaces
Authors: Marconi Umberto Marini Bettolo , Melchionna Simone
Published: February 2011

A multicomponent extension of our recent theory of simple fluids [U. M. B. Marconi and S. Melchionna, J. Chem. Phys. 131, 014105 (2009)] is proposed to describe miscible and immiscible liquid mixtures under inhomogeneous, nonsteady conditions typical of confined fluid flows. We first derive from a microscopic level the evolution equations of the phase space distribution function of each component in terms of a set of self-consistent fields, representing both body forces and viscous forces (forces dependent on the density distributions in the fluid and on the velocity distributions). Second, we numerically solve the resulting governing equations by means of the lattice Boltzmann method, whose implementation contains novel features with respect to existing approaches. Our model incorporates hydrodynamic flow, diffusion, surface tension, and the possibility for global and local viscosity variations. We validate our model by studying the bulk viscosity dependence of the mixture on concentration, packing fraction, and size ratio. Finally, we consider inhomogeneous systems and study the dynamics of mixtures in slits of molecular thickness and relate structural and flow properties.
Escape of polymer chains from an attractive channel under electrical force
Authors: Wang Chao , Chen Ying-Cai , Zhou Yan-Li , Luo Meng-Bo
Published: February 2011

The escape of polymer chains from an attractive channel under external electrical field is studied using dynamical Monte Carlo method. Though the escaping process is nonequilibrium in nature, results show that the one-dimensional diffusion theoretical model based on the equilibrium assumption can describe the dependence of the average escaping time (τ0) on the polymer–channel interaction (ɛ), the electrical field (E), the chain length (n), and the channel length (L), qualitatively. Results indicate that both ɛ and E play very important roles in the escaping dynamics. For small ɛ, the polymer chain moves out of the channel continuously and quickly. While for large ɛ, the polymer chain is difficult to move out of long channels as it is trapped for a long time (τtrap) when the end segment is near the critical point xC. These results are consistent with the theoretical results for the free energy profiles at small ɛ and large ɛ, respectively. The dependence of xC and τtrap on ɛ and E are discussed, and specific relations are obtained. The configurational properties of polymer chain are also investigated during the escaping process.
Evaporative self-assembly of nanowires on superhydrophobic surfaces of nanotip latching structures
Authors: Xu Wei , Leeladhar Rajesh , Tsai Yao-Tsan , Yang Eui-Hyeok , Choi Chang-Hwan
Published: February 2011

In this letter, we report a site-specific self-assembly of nanowires during the evaporation of a colloid droplet of nanowires on nanoengineered superhydrophobic surfaces. The self-assembly of nanowires is achieved by the interactions between nanowires and the superhydrophobic surface engineered with sharp-tip latching nanostructures of micropillars, provided by the convective hydrodynamic flow and the receding three-phase contact line of the evaporating droplet. The experimental results show that the spatial density of surface structures, the relative dimension of surface patterns to nanowires, and the morphology of tip surface influence the self-assembly and alignment of nanowires on the evaporative superhydrophobic surface.
LaVO
4
:
Eu
Phosphor films with enhanced Eu solubility
Authors: Higuchi T. , Hotta Y. , Hikita Y. , Maruyama S. , Hayamizu Y. , Akiyama H. , Wadati H. , Hawthorn D. G. , Regier T. Z. , Blyth R. I. R. , Sawatzky G. A. , Hwang H. Y.
Published: February 2011

Eu doped rare-earth orthovanadates are known to be good red phosphor materials. In particular, LaVO4:Eu is a promising candidate due to the low Eu-site point symmetry, and thus high dipole transition probability within Judd–Ofelt theory. However, the low solubility limit (<3 mol %) of Eu in LaVO4 prevents its efficient use as a phosphor. We present optical evidence of enhanced Eu solubility as high as 10 mol % in LaVO4:Eu thin films grown by pulsed laser deposition and postannealing. The photoluminescent intensity exceeded that of YVO4:Eu thin films when excited below the host bandgap, indicating stronger direct emission of Eu in LaVO4.
Subwavelength imaging in a cylindrical hyperlens based on S-string resonators
Authors: Zhang Weibin , Chen Hongsheng , Moser Herbert O.
Published: February 2011

Previous cylindrical hyperlenses were realized with metamaterial with only one component of the constitutive parameters negative. In this letter, we show that metamaterials with different combinations of negative and positive constitutive parameters can also be used to realize hyperlenses. The metamaterial forming the cylindrical hyperlens is based on the S-string architecture, which shows two components of the constitutive parameters negative, i.e., μϕ<0 and εz<0. Both simulation and experimental studies of the cylindrical hyperlens show that a spatial resolution of about 1/10 of the vacuum wavelength can be obtained.
Spectroscopic investigation of confinement effects on optical properties of graphene oxide
Authors: Shukla Shobha , Saxena Sumit
Published: February 2011

The effect of electron confinement due to the formation of graphitic islands in graphene oxide has been studied using optical techniques. Photoluminescence studies indicate a strong ultraviolet (UV) emission at ∼356 nm along with a broadened feature in the green region of the visible electromagnetic spectrum. Strong UV emission suggests probable application of graphene oxide in photodynamic therapy and nanophotonic devices.
Ab initio potential energy surface and intermolecular vibrations of the naphthalene-argon van der Waals complex
Authors: Makarewicz Jan
Published: February 2011

The intermolecular potential energy surface (PES) of the naphthalene-argon (NpAr) complex is constructed using an ab initio method. The molecule-argon interaction energy is computed at the level of the second-order Møller–Plesset (MP2) theory combined with the augmented correlation consistent polarized valence double-ζ basis set. The analytical PES fitted to a large set of single energy values is further improved with the help of correction functions determined by calculations of the interaction energy at the coupled cluster level including single and double excitations supplemented by triple excitations performed for a limited set of intermolecular configurations. The PES determined is very flat near its four equivalent global minima of –493 cm−1 located from both sides of the Np plane at a distance of 3.435 Å and shifted from the center of Np by ±0.43 Å along its long symmetry axis. The large-amplitude motion of Ar in the complex is investigated, and dynamical consequence of a strong intermode coupling is discovered in the excited vibrational states. The theoretical results obtained allow for the reassignment of the spectral bands observed in the electronic transition S1 ← S0 of the NpAr complex.
Novel Doped Tungstovanadate and Molybdovanadate with Bi-antimony-Capped Keggin Structure
Authors: Han Zhangang , Wu Jingjing , Gao Yuanzhe , Zhai Xueliang
Published: February 2011

Three novel V-centred Keggin-based compounds containing cap-shaped Sb atoms: (HDMF)2[(VO4)W5.65V7.74Sb2.61O36.77]·6H2O (1), [Co(phen)3]2[(VO4)Mo9.58V2.42Sb2O36]·6H2O (2) and [Ni(phen)2(H2O)]2[(VO4)Mo8V4Sb2O36]·2H2O (3) (DMF = dimethylformamide; phen = 1,10-phenanthroline) have been synthesized and characterized. X-ray diffraction analysis revealed that compound 1 consists of an unusually one-dimensional 12-tungstovanadate Keggin-based polymer, in which the reduced tungstovanadate Keggin species are stabilized by introducing capping {VO} and {Sb} groups and then linked into chains via V(Sb)–O–V(Sb) interactions. Both 2 and 3 are built from secondary metal–ligand groups (Co-phen for 2, Ni-phen for 3) and 12-molybdovanadate doped Keggin-type cores with two antimony atoms capping two opposite sites. The anion in 3 represents a bi-capped and bi-supported Keggin-type structure. The electrochemical properties of 2- and 3-modified carbon paste electrodes (2-CPE and 3-CPE) are also studied.
Synthesis, and Acid–Base and DNA-Binding Properties of a Thiophen-Appended Ruthenium Complex
Authors: Luo Hong , Wang Zhi-Ping , Zhang An-Guo , Wang Ke-Zhi
Published: February 2011

2-(5-Phenylthiophen-2-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (Hptip) and its RuII complex [Ru(bpy)2(Hptip)](PF6)2 (where bpy = 2,2′-bipyridine) have been synthesized and characterized by elemental analysis, 1H NMR spectroscopy, and mass spectrometry. The acid–base properties of the complex were studied by UV-visible and luminescence spectrophotometric pH titrations, and ground- and excited-state acidity ionization constants were derived. The DNA-binding properties of [Ru(bpy)2(Hptip)](PF6)2 were also investigated by means of UV-vis and emission spectroscopy, salt effects, steady-state emission quenching by [Fe(CN)6]4–, DNA competitive binding with ethidium bromide, DNA melting experiments, and viscosity measurements. Density functional theoretical calculations were also carried out in order to understand the DNA binding properties.
Photoactive and Electroactive Dendrimers: Future Trends and Applications
Authors: Ceroni Paola , Venturi Margherita
Published: February 2011

The initial interest in dendrimer chemistry was the synthesis of such aesthetically pleasant macromolecules. Nowadays, the field is moving to applications in various multidisciplinary areas, such as medicine, biology, chemistry, physics, and engineering, i.e. at the interface of many disciplines. This short review describes some promising applications of photoactive and electroactive dendrimers as artificial enzymes, molecular batteries, sensors with signal amplification, photoswitchable hosts, systems for energy up-conversion, and light-harvesting antennas. The reported examples clearly show that these applications take advantage of the unique aspects of dendrimer structure: (i) three-dimensional array; (ii) generation-dependent size; (iii) presence of selected functional units in predetermined sites; and (iv) endo- and exo-receptor capabilities.
Pan-genome of the dominant human gut-associated archaeon,
Methanobrevibacter smithii
, studied in twins
Authors: Hansen Elizabeth E. , Lozupone Catherine A. , Rey Federico E. , Wu Meng , Guruge Janaki L. , Narra Aneesha , Goodfellow Jonathan , Zaneveld Jesse R. , McDonald Daniel T. , Goodrich Julia A. , Heath Andrew C. , Knight Rob , Gordon Jeffrey I.
Published: February 2011

The human gut microbiota harbors three main groups of H
2
-consuming microbes: methanogens including the dominant archaeon,
Methanobrevibacter smithii
, a polyphyletic group of acetogens, and sulfate-reducing bacteria. Defining their roles in the gut is important for understanding how hydrogen metabolism affects the efficiency of fermentation of dietary components. We quantified methanogens in fecal samples from 40 healthy adult female monozygotic (MZ) and 28 dizygotic (DZ) twin pairs, analyzed bacterial 16S rRNA datasets generated from their fecal samples to identify taxa that co-occur with methanogens, sequenced the genomes of 20
M. smithii
strains isolated from families of MZ and DZ twins, and performed RNA-Seq of a subset of strains to identify their responses to varied formate concentrations. The concordance rate for methanogen carriage was significantly higher for MZ versus DZ twin pairs. Co-occurrence analysis revealed 22 bacterial species-level taxa positively correlated with methanogens: all but two were members of the Clostridiales, with several being, or related to, known hydrogen-producing and -consuming bacteria. The
M. smithii
pan-genome contains 987 genes conserved in all strains, and 1,860 variably represented genes. Strains from MZ and DZ twin pairs had a similar degree of shared genes and SNPs, and were significantly more similar than strains isolated from mothers or members of other families. The 101 adhesin-like proteins (ALPs) in the pan-genome (45 ± 6 per strain) exhibit strain-specific differences in expression and responsiveness to formate. We hypothesize that
M. smithii
strains use their different repertoires of ALPs to create diversity in their metabolic niches, by allowing them to establish syntrophic relationships with bacterial partners with differing metabolic capabilities and patterns of co-occurrence.
Identifying organic aerosol sources by comparing functional group composition in chamber and atmospheric particles
Authors: Russell Lynn M. , Bahadur Ranjit , Ziemann Paul J.
Published: February 2011

Measurements of submicron particles by Fourier transform infrared spectroscopy in 14 campaigns in North America, Asia, South America, and Europe were used to identify characteristic organic functional group compositions of fuel combustion, terrestrial vegetation, and ocean bubble bursting sources, each of which often accounts for more than a third of organic mass (OM), and some of which is secondary organic aerosol (SOA) from gas-phase precursors. The majority of the OM consists of alkane, carboxylic acid, hydroxyl, and carbonyl groups. The organic functional groups formed from combustion and vegetation emissions are similar to the secondary products identified in chamber studies. The near absence of carbonyl groups in the observed SOA associated with combustion is consistent with alkane rather than aromatic precursors, and the absence of organonitrate groups can be explained by their hydrolysis in humid ambient conditions. The remote forest observations have ratios of carboxylic acid, organic hydroxyl, and nonacid carbonyl groups similar to those observed for isoprene and monoterpene chamber studies, but in biogenic aerosols transported downwind of urban areas the formation of esters replaces the acid and hydroxyl groups and leaves only nonacid carbonyl groups. The carbonyl groups in SOA associated with vegetation emissions provides striking evidence for the mechanism of esterification as the pathway for possible oligomerization reactions in the atmosphere. Forest fires include biogenic emissions that produce SOA with organic components similar to isoprene and monoterpene chamber studies, also resulting in nonacid carbonyl groups in SOA.
Glass-like dynamics of collective cell migration
Authors: Angelini Thomas E. , Hannezo Edouard , Trepat Xavier , Marquez Manuel , Fredberg Jeffrey J. , Weitz David A.
Published: February 2011

Collective cell migration in tissues occurs throughout embryonic development, during wound healing, and in cancerous tumor invasion, yet most detailed knowledge of cell migration comes from single-cell studies. As single cells migrate, the shape of the cell body fluctuates dramatically through cyclic processes of extension, adhesion, and retraction, accompanied by erratic changes in migration direction. Within confluent cell layers, such subcellular motions must be coupled between neighbors, yet the influence of these subcellular motions on collective migration is not known. Here we study motion within a confluent epithelial cell sheet, simultaneously measuring collective migration and subcellular motions, covering a broad range of length scales, time scales, and cell densities. At large length scales and time scales collective migration slows as cell density rises, yet the fastest cells move in large, multicell groups whose scale grows with increasing cell density. This behavior has an intriguing analogy to dynamic heterogeneities found in particulate systems as they become more crowded and approach a glass transition. In addition we find a diminishing self-diffusivity of short-wavelength motions within the cell layer, and growing peaks in the vibrational density of states associated with cooperative cell-shape fluctuations. Both of these observations are also intriguingly reminiscent of a glass transition. Thus, these results provide a broad and suggestive analogy between cell motion within a confluent layer and the dynamics of supercooled colloidal and molecular fluids approaching a glass transition.
RETRACTED: Activation of the NF-κB pathway by adeno-associated virus (AAV) vectors and its implications in immune response and gene therapy
Authors: Jayandharan Giridhara R. , Aslanidi George , Martino Ashley T. , Jahn Stephan C. , Perrin George Q. , Herzog Roland W. , Srivastava Arun
Published: February 2011

Because our in silico analysis with a human transcription factor database demonstrated the presence of several binding sites for NF-κB, a central regulator of cellular immune and inflammatory responses, in the adeno-associated virus (AAV) genome, we investigated whether AAV uses NF-κB during its life cycle. We used small molecule modulators of NF-κB in HeLa cells transduced with recombinant AAV vectors. VP16, an NF-κB activator, augmented AAV vector-mediated transgene expression up to 25-fold. Of the two NF-κB inhibitors, Bay11, which blocks both the canonical and the alternative NF-κB pathways, totally ablated transgene expression, whereas pyrrolidone dithiocarbamate, which interferes with the classical NF-κB pathway, had no effect. Western blot analyses confirmed the abundance of the nuclear p52 protein component of the alternative NF-κB pathway in the presence of VP16, which was ablated by Bay11, suggesting that AAV transduction activates the alternative NF-κB pathway. In vivo, hepatic AAV gene transfer activated the canonical NF-κB pathway within 2 h, resulting in expression of proinflammatory cytokines and chemokines (likely reflecting the sensing of viral particles by antigen-presenting cells), whereas the alternative pathway was activated by 9 h. Bay11 effectively blocked activation of both pathways without interfering with long-term transgene expression while eliminating proinflammatory cytokine expression. These studies suggest that transient immunosuppression with NF-κB inhibitors before transduction with AAV vectors should lead to a dampened immune response, which has significant implications in the optimal use of AAV vectors in human gene therapy.
Wounding mobilizes hair follicle stem cells to form tumors
Authors: Wong Sunny Y. , Reiter Jeremy F.
Published: February 2011

A wide variety of human cancers are associated with injury. Although stem cells participate in tissue regeneration after wounding, it is unclear whether these cells also contribute to epithelial tumors. Human basal cell carcinomas (BCCs) are associated with misactivation of Hedgehog (Hh) signaling, commonly through acquisition of mutations in
Smoothened
(
Smo
). We have found that expression of an activated form of Smo by stem cells of the hair-follicle bulge and secondary hair germ does not induce robust Hh signaling or produce BCCs. However, wounding recruits these cells from the follicle to the wound site, where downstream Hh signal transduction is derepressed, giving rise to superficial BCC-like tumors. These findings demonstrate that BCC-like tumors can originate from follicular stem cells and provide an explanation for the association between wounding and tumorigenesis.
Magnetometry with mesospheric sodium
Authors: Higbie James M. , Rochester Simon M. , Patton Brian , Holzlöhner Ronald , Bonaccini Calia Domenico , Budker Dmitry
Published: February 2011

Measurement of magnetic fields on the few 100-km length scale is significant for many geophysical applications including mapping of crustal magnetism and ocean circulation measurements, yet available techniques for such measurements are very expensive or of limited accuracy. We propose a method for remote detection of magnetic fields using the naturally occurring atomic sodium-rich layer in the mesosphere and existing high-power lasers developed for laser guide star applications. The proposed method offers a dramatic reduction in cost and opens the way to large-scale, parallel magnetic mapping and monitoring for atmospheric science, navigation, and geophysics.
Trypanosome REH1 is an RNA helicase involved with the 3′–5′ polarity of multiple gRNA-guided uridine insertion/deletion RNA editing
Authors: Li Feng , Herrera Jeremy , Zhou Sharleen , Maslov Dmitri A. , Simpson Larry
Published: February 2011

Uridine insertion/deletion RNA editing in kinetoplastid mitochondria corrects encoded frameshifts in mRNAs. The genetic information for editing resides in small guide RNAs (gRNAs), which form anchor duplexes just downstream of an editing site and mediate editing within a single editing “block.” Many mRNAs require multiple gRNAs; the observed overall 3′ to 5′ polarity of editing is determined by the formation of upstream mRNA anchors by downstream editing. Hel61, a mitochondrial DEAD-box protein, was previously shown to be involved in RNA editing, but the functional role was not clear. Here we report that down-regulation of Hel61 [renamed REH1 (RNA editing helicase 1)] expression in
Trypanosoma brucei
selectively affects editing mediated by two or more overlapping gRNAs but has no effect on editing within a single block. Down-regulation produces an increased abundance of the gRNA/edited mRNA duplex for the first editing block of the A6 mRNA. Recombinant REH1 has an ATP-dependent double strand RNA unwinding activity in vitro with a model gRNA-mRNA duplex. These data indicate that REH1 is involved in gRNA displacement either directly by unwinding the gRNA/edited mRNA duplex or indirectly, to allow the 5′ adjacent upstream gRNA to form an anchor duplex with the edited mRNA to initiate another block of editing. Purified tagged REH1 is associated with the RNA editing core complex by RNA linkers and a colocalization of REH1, REL1, and two kinetoplast ribosomal proteins with the kinetoplast DNA was observed by immunofluorescence, suggesting that editing, transcription, and translation may be functionally linked.
Transient binding of dynein controls bidirectional long-range motility of early endosomes
Authors: Schuster Martin , Lipowsky Reinhard , Assmann Marcus-Alexander , Lenz Peter , Steinberg Gero
Published: February 2011

In many cell types, bidirectional long-range endosome transport is mediated by the opposing motor proteins dynein and kinesin-3. Here we use a fungal model system to investigate how both motors cooperate in early endosome (EE) motility. It was previously reported that Kin3, a member of the kinesin-3 family, and cytoplasmic dynein mediate bidirectional motility of EEs in the fungus
Ustilago maydis
. We fused the green fluorescent protein to the endogenous dynein heavy chain and the
kin3
gene and visualized both motors and their cargo in the living cells. Whereas kinesin-3 was found on anterograde and retrograde EEs, dynein motors localize only to retrograde organelles. Live cell imaging shows that binding of retrograde moving dynein to anterograde moving endosomes changes the transport direction of the organelles. When dynein is leaving the EEs, the organelles switch back to anterograde kinesin-3–based motility. Quantitative photobleaching and comparison with nuclear pores as an internal calibration standard show that single dynein motors and four to five kinesin-3 motors bind to the organelles. These data suggest that dynein controls kinesin-3 activity on the EEs and thereby determines the long-range motility behavior of the organelles.