bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Cyanobacterial Lipopolysaccharides from Microcystis on Glutathione-Based Detoxification Pathways in the Zebrafish (Danio rerio) Embryo
Authors: Jaja-Chimedza Asha , Gantar Miroslav , Mayer Gregory D. , Gibbs Patrick D. L. , Berry John P.
Published: May 2012

Cyanobacteria (“blue-green algae”) are recognized producers of a diverse array of toxic secondary metabolites. Of these, the lipopolysaccharides (LPS), produced by all cyanobacteria, remain to be well investigated. In the current study, we specifically employed the zebrafish (Danio rerio) embryo to investigate the effects of LPS from geographically diverse strains of the widespread cyanobacterial genus, Microcystis, on several detoxifying enzymes/pathways, including glutathione-S-transferase (GST), glutathione peroxidase (GPx)/glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT), and compared observed effects to those of heterotrophic bacterial (i.e., E. coli) LPS. In agreement with previous studies, cyanobacterial LPS significantly reduced GST in embryos exposed to LPS in all treatments. In contrast, GPx moderately increased in embryos exposed to LPS, with no effect on reciprocal GR activity. Interestingly, total glutathione levels were elevated in embryos exposed to Microcystis LPS, but the relative levels of reduced and oxidized glutathione (i.e., GSH/GSSG) were, likewise, elevated suggesting that oxidative stress is not involved in the observed effects as typical of heterotrophic bacterial LPS in mammalian systems. In further support of this, no effect was observed with respect to CAT or SOD activity. These findings demonstrate that Microcystis LPS affects glutathione-based detoxification pathways in the zebrafish embryo, and more generally, that this model is well suited for investigating the apparent toxicophore of cyanobacterial LPS, including possible differences in structure-activity relationships between heterotrophic and cyanobacterial LPS, and teleost fish versus mammalian systems.
BICKEL–ROSENBLATT TEST FOR WEAKLY DEPENDENT DATA
Authors: Valeinis Janis , Locmelis Audris
Published: May 2012

The aim of this paper is to analyze the Bickel–Rosenblatt test for simple hypothesis in case of weakly dependent data. Although the test has nice theoretical properties, it is not clear how to implement it in practice. Choosing different band-width sequences first we analyze percentage rejections of the test statistic under H0 by some empirical simulation analysis. This can serve as an approximate rule for choosing the bandwidth in case of simple hypothesis for practical implementation of the test. In the recent paper [12] a version of Neyman goodness-of-fit test was established for weakly dependent data in the case of simple hypotheses. In this paper we also aim to compare and discuss the applicability of these tests for both independent and dependent observations.
SOLVABILITY OF BOUNDARY VALUE PROBLEMS FOR SINGULAR QUASI-LAPLACIAN DIFFERENTIAL EQUATIONS ON THE WHOLE LINE
Authors: Liu Yuji
Published: May 2012

This paper is concerned with some integral type boundary value problems associated to second order singular differential equations with quasi-Laplacian on the whole line. The emphasis is put on the one-dimensional p-Laplacian term involving a nonnegative function ρ that may be singular at t = 0 and such that . A Banach space and a nonlinear completely continuous operator are defined in this paper. By using the Schauder's fixed point theorem, sufficient conditions to guarantee the existence of at least one solution are established. An example is presented to illustrate the main theorem.
ALGORITHMS FOR NUMERICAL SOLVING OF 2D ANOMALOUS DIFFUSION PROBLEMS
Authors: Abrashina-Zhadaeva Natalia , Romanova Natalie
Published: May 2012

Fractional analog of the reaction diffusion equation is used to model the subdiffusion process. Diffusion equation with fractional Riemann–Liouville operator is analyzed in this paper. We offer finite-difference methods that can be used to solve the initial-boundary value problems for some time-fractional order differential equations. Stability and convergence theorems are proved.
Commerce à distance et voyage d'affaires. Les missions a Gênes et à Cadix de Jean-Joseph Leydet, un commis qui voyage (1803-1804)
Authors: Bartolomei Arnaud
Published: May 2012

Résumé Au XVIII e siècle parmi les différentes manières d’accroître leurs ventes, les négociants lyonnais de la soierie et de la mode privilégient le système des commis voyageurs auxquels ils donnent des directives très précises concernant les itinéraires, les logements, les moyens de transport à utiliser et le temps à passer dans les différentes villes. Leurs préparatifs effectués, les commis doivent ajuster le moment de leur départ pour lutter contre la concurrence. Sur place, leurs déplacements permanents leur permettent de s’informer, de régler de multiples problèmes et de développer la clientèle tout en rendant compte régulièrement de leurs démarches à leurs mandants. Ce travail incessant presque sans temps de repos use les commis. Les négociants n’en ont cependant guère cure : leurs voyages doivent être rentables ou ne pas exister.
« Au service de mercure » : réflexions sur une histoire économique et culturelle des commis voyageurs en Suisse, de 1890 a 1980
Authors: Rossfeld Roman
Published: May 2012

Résumé Dès la seconde moitié du XIX e siècle, les voyageurs de commerce jouèrent un rôle croissant dans les interactions entre l’entreprise et le marché ainsi que dans la genèse des marchés. Mais en tant que représentants d’un monde nouveau, encore inhabituel, ils ne furent pas forcément bien vus partout d’un bon œil - au même titre que la présence croissante de la publicité d’ailleurs. Le présent article analyse d’abord, sur la base du cas suisse, l’évolution totale du nombre des commis voyageurs et notamment les deux questions essentielles de la chronologie de leur apparition et des secteurs dans lesquels ils ont eu une fonction importante pour la vente et la commercialisation des produits. À partir de l’exemple de la Société Suisse des Voyageurs de Commerce (SSVC), fondée en 1878, l’étude porte également sur leur organi­sation en tant que corps de métier, leur professionnalisation progressive ainsi que sur leur mauvaise image initiale – en dehors des entreprises – et sur le processus différenciation qui amena à les distinguer peu à peu des marchands ambulants et des colporteurs.
2-Methoxyestradiol-bis-sulphamate disrupts microtubule network, arrests cell cycle and induces apoptosis in an esophageal carcinoma cell line
Authors: Mqoco T.V. , Marais Sumari , Joubert Annie M.
Published: May 2012

Future in vitro studies into the mechanism of this potentially anticancer drug are warranted.
Using non-negative matrix factorization for the identification of daily patterns of particulate air pollution in Beijing during 2004–2008
Authors: Thiem A. , Schlink U. , Pan X.-C. , Hu M. , Peters A. , Wiedensohler A. , Breitner S. , Cyrys J. , Wehner B. , Rösch C. , Franck U.
Published: May 2012

Abstract. Increasing traffic density and a changing car fleet on the one hand as well as various reduction measures on the other hand may influence the composition of the particle population and, hence, the health risks for residents of megacities like Beijing. A suitable tool for identification and quantification of source group-related particle exposure compositions is desirable in order to derive optimal adaptation and reduction strategies and therefore, is presented in this paper. Particle number concentrations have been measured in high time- and space-resolution at an urban background monitoring site in Beijing, China, during 2004–2008. In this study a new pattern recognition procedure based on non-negative matrix factorization (NMF) was introduced to extract characteristic diurnal air pollution patterns of particle number and volume size distributions for the study period. Initialization and weighting strategies for NMF applications were carefully considered and a scaling procedure for ranking of obtained patterns was implemented. In order to account for varying particle sizes in the full diameter range [3 nm; 10 μm] two separate NMF applications (a) for diurnal particle number concentration data (NMF-N) and (b) volume concentration data (NMF-V) have been performed. Five particle number concentration-related NMF-N factors were assigned to patterns mainly describing the development of ultrafine (particle diameter Dp < 100 nm instead of DP) as well as fine particles (Dp < 2.5 μm), since absolute number concentrations are highest in these diameter ranges. The factors are classified into primary and secondary sources. Primary sources mostly involved anthropogenic emission sources such as traffic emissions or emissions of nearby industrial plants, whereas secondary sources involved new particle formation and accumulation (particle growth) processes. For the NMF-V application the five extracted factors mainly described coarse particle (2.5 μm < Dp < 10 μm) variations, generated by processes like dust storm events. Because particle volume depends on particle diameter in a cubic manner, larger particles are emphasized in the latter application. In order to gain insight in the day-by-day varying source-associated composition of the particle burden non-negative linear combinations of individual source-associated pollution patterns were used to approximate the original particle data. Consequently, this NMF-based procedure provides a reasonable numerical-statistical tool for the description of daily patterns of particle pollution, source identification and reconstruction of daily patterns by summarizing weighted factors.
Application of tomographic algorithms to Polar Mesospheric Cloud observations by Odin/OSIRIS
Authors: Hultgren K. , Gumbel J. , Degenstein D. A. , Bourassa A. E. , Lloyd N. D.
Published: May 2012

Abstract. Limb-scanning satellites can provide global information about the vertical structure of Polar Mesospheric Clouds. However, information about horizontal structures usually remains limited. This is due to both a long line of sight and a long scan duration. On eighteen days during the Northern Hemisphere summers 2010–2011 and the Southern Hemisphere summer 2011/2012, the Swedish-led Odin satellite was operated in a special mesospheric mode with short limb scans limited to the altitude range of Polar Mesospheric Clouds. For Odin's Optical Spectrograph and InfraRed Imager System (OSIRIS) this provides multiple views through a given cloud volume and, thus, a basis for tomographic analysis of the vertical/horizontal cloud structure. Here we present algorithms for tomographic analysis of mesospheric clouds based on maximum probability techniques. We also present results of simulating OSIRIS tomography and retrieved cloud structures from the special tomographic periods.
Primary Productivity and heterotrophic activity in an enclosed marine area of central Patagonia (Puyuhuapi channel; 44° S, 73° W)
Authors: Daneri G. , Montero P. , Lizárraga L. , Torres R. , Iriarte J. L. , Jacob B. , González H. E. , Tapia F. J.
Published: May 2012

Abstract. We assessed temporal variability in phytoplankton biomass, Chlorophyll a, nutrient availability, Gross Primary Production (GPP), community respiration (CR), and bacterial secondary production (BSP) over a year of monthly observations (October 2007 to October 2008) at a fixed station in the Puyuhuapi fjord, Chilean Patagonia (44° S, 73° W). A set of in situ observations gathered over two consecutive spring-summer seasons, and one autumn-winter season in the middle, has made it possible to connect the two-phase (i.e. productive season/non-productive season) pattern of Chlorophyll a (Chl a) variability shown by satellite data with a two-phase cycle in GPP, CR, and the composition of phytoplankton assemblages. Estimates of annual GPP and CR, integrated over the top 20 meters of the water column, were 533 and 537 g C m−2 yr−1, respectively. Low values of pCO2 were measured in mixed layer autotrophic waters (GPP/CR > 1) while high pCO2 levels were measured in mixed layer heterotrophic waters (GPP/CR < 1). Bacterial Secondary Production (BSP) was significantly and positively correlated with GPP (r = 0.6, p < 0.05, n = 24) and Chl a (r = 0.4, p < 0.05, n = 24) on an annual cycle basis. The winter drop in bacterioplankton (both bacteria and archea) activity (from 0.9 ± 0.6 g C m−2 d−1 to 0.6 ± 0.3 g C m−2 d−1) was not as pronounced as the winter drop in phytoplankton activity (from 1.1 ± 1.12 g C m−2 d−1 to 0.1 ± 0.09 g C m−2 d−1). It is hypothesized that dissolved organic matter (DOM) of terrestrial origin plays an important role (especially in winter) supporting bacterial activity in the Puyuhuapi fjord.
Adaptive stabilization of a class of high‐order uncertain nonholonomic systems with unknown control coefficients
Authors: Zhang Jian , Liu Yungang
Published: May 2012

This paper is concerned with the globally stabilizing control design for a class of high‐order nonholonomic systems. Compared with the existing literature, the high‐order nonholonomic systems under investigations have more uncertainties and unknowns, such as neither lower nor upper bound is known for each control coefficient of the systems. This renders the existing control methods highly difficult to the control problems of the systems or even inapplicable. In this paper, by defining two new unknown parameters whose dynamic updating laws are properly chosen and also by using the discontinuous coordinates transformation and the method of adding a power integrator, a new design approach is given to the adaptive stabilizing controllers for the systems. A numerical simulation is provided to demonstrate the effectiveness of the theoretical results. Copyright © 2012 John Wiley & Sons, Ltd.
Germline mosacism in Shprintzen–Goldberg syndrome
Authors: Shanske Alan L. , Goodrich James T. , Ala‐Kokko Leena , Baker Stuart , Frederick Barbara , Levy Brynn
Published: May 2012

We report on maternal half‐sibs born to unaffected, non‐consanguineous parents with classical Shprintzen–Goldberg syndrome (SGS) who had in addition intestinal malrotation and an aberrant subclavian artery. In one other SGS family germline mosaicism has been described. SGS is molecularly heterogeneous and has been linked to mutations in three genomic loci. This suggests there may be multiple other genetic factors that result in a common clinical phenotype and a number of investigators have implicated a fourth region (15q25‐qter) in the etiology of SGS. © 2012 Wiley Periodicals, Inc.
Relation of neuropathology to cognition in persons without cognitive impairment
Authors: Bennett David A. , Wilson Robert S. , Boyle Patricia A. , Buchman Aron S. , Schneider Julie A.
Published: May 2012

Objective:

A study was undertaken to examine the relation of Alzheimer disease (AD) pathology, cerebral infarcts, and Lewy body (LB) pathology to cognition in persons without cognitive impairment.

Methods:

Persons without dementia from 2 cohort studies of aging, the Religious Orders Study and the Memory and Aging Project, agreed to annual clinical evaluation and brain donation. The studies had 19 neuropsychological performance tests in common that assessed 5 cognitive domains. For 296 persons without cognitive impairment who died and underwent postmortem assessment, we quantified AD pathology as a global pathology score, and as amyloid load, paired helical filament tau‐positive (PHFtau) tangle density, cerebral infarcts, and LB pathology. Linear regression was used to examine the relation of neuropathology to cognitive abilities, controlling for demographics.

Results:

Nearly all persons had AD pathology with >¾ exhibiting amyloid; 22% had macroscopic and 24% had microscopic infarctions, and 13% had LB pathology. The global measure of AD pathology was related to global cognition (p = 0.008), whereas infarcts and Lewy bodies were not. Amyloid load was related to global cognition (p < 0.05), with only a trend for tangles (p = 0.08). In analyses of cognitive domains, AD pathology (p = 0.006), PHFtau tangles (p = 0.03), and macroscopic infarctions (p = 0.02) were related to episodic memory, with a trend for amyloid load (p = 0.06); AD pathology (p = 0.02) and amyloid load (p = 0.03) were related to working memory. Findings for global cognition and episodic memory were stronger in additional analyses with neocortical amyloid and mesial temporal tangles.

Interpretation:

AD pathology and macroscopic infarctions are common in older persons without cognitive impairment and are related to episodic and working memory. ANN NEUROL 2012;72:599–609
Biomineralization as an Inspiration for Materials Chemistry
Authors: Nudelman Fabio , Sommerdijk Nico A. J. M.
Published: May 2012

Living organisms are well known for building a wide range of specially designed organic–inorganic hybrid materials such as bone, teeth, and shells, which are highly sophisticated in terms of their adaptation to function. This has inspired physicists, chemists, and materials scientists to mimic such structures and their properties. In this Review we describe how strategies used by nature to build and tune the properties of biominerals have been applied to the synthesis of materials for biomedical, industrial, and technological purposes. Bio‐inspired approaches such as molecular templating, supramolecular templating, organized surfaces, and phage display as well as methods to replicate the structure and function of biominerals are discussed. We also show that the application of in situ techniques to study and visualize the bio‐inspired materials is of paramount importance to understand, control, and optimize their preparation. Biominerals are synthesized in aqueous media under ambient conditions, and these approaches can lead to materials with a reduced ecological footprint than can traditional methods.
Sensitive Detection of Small Molecule–Protein Interactions on a Metal–Insulator–Metal Label‐Free Biosensing Platform
Authors: Syahir Amir , Kajikawa Kotaro , Mihara Hisakazu
Published: May 2012

The need to develop label‐free biosensing devices that enable rapid analyses of interactions between small molecules/peptides and proteins for post‐genomic studies has increased significantly. We report a simple metal–insulator–metal (MIM) geometry for fabricating a highly sensitive detection platform for biosensing. MIM substrates consisting of an Au–PMMA–Ag nanolayer were extensively studied using both theoretical and experimental approaches. By monitoring reflectivity changes at the normal incidence angle, we observed molecular interactions as the thickness of the biolayer increased on the substrate surface. These interactions included the adsorption of various proteins (Mw=6–150 kD) and interactions between small molecules (Mw≤2 kD) and the immobilized proteins. The interaction of designed monosaccharide‐modified designed peptides with various lectins was also clearly detected. These interactions could not be detected by the conventional Au‐only substrate. Thus, the MIM approach affords a powerful label‐free biosensing device that will aid our understanding of protein interactions and recognition.
Cover Picture: Naphthalene and Anthracene Complexes Sandwiched by Two {(Cp*)FeI} Fragments: Strong Electronic Coupling between the FeI Centers (Chem. Asian J. 6/2012)
Authors: Hatanaka Tsubasa , Ohki Yasuhiro , Kamachi Takashi , Nakayama Tomonori , Yoshizawa Kazunari , Katada Motomi , Tatsumi Kazuyuki
Published: May 2012

No Abstract
Improving extreme precipitation forecasts in Rio de Janeiro, Brazil: are synoptic patterns efficient for distinguishing ordinary from heavy rainfall episodes?
Authors: Dolif Giovanni , Nobre Carlos
Published: May 2012

This work analysed heavy rainfall events and their predictability on Rio de Janeiro, Brazil, using rain gauge data from 2000 to 2010, atmospheric model outputs, and an artificial neural network based on adaptive resonance theory. The latter was applied on top of atmospheric simulations for 2009 and 2010, and we were able to predict 55% of the heavy rainfall events using a combination of relative humidity at 900 hPa and meridional winds at 10 m for a domain covering central and southern Brazil, which represents a relative gain of 67% on predictability when compared to the model predicted rainfall. Copyright © 2012 Royal Meteorological Society
Randomized clinical trial of ultrasound-guided foam sclerotherapy versus surgery for the incompetent great saphenous vein
Authors: Shadid N , Ceulen R , Nelemans P , Dirksen C , Veraart J , Schurink G W , van Neer P , vd Kley J , de Haan E , Sommer A
Published: May 2012

Background

New minimally invasive treatment modalities, such as ultrasound-guided foam sclerotherapy (UGFS), are becoming more popular. In a multicentre randomized controlled non-inferiority trial, the effectiveness and costs of UGFS and surgery for treatment of the incompetent great saphenous vein (GSV) were compared.

Methods

Patients with primary great saphenous varicose veins were assigned randomly to either UGFS or surgical stripping with high ligation. Recurrence, defined as reflux combined with venous symptoms, was determined on colour duplex scans at baseline, 3 months, 1 year and 2 years after initial treatment. Secondary outcomes were presence of recurrent reflux (irrespective of symptoms), reduction of symptoms, health-related quality of life (EQ-5D™), adverse events and direct hospital costs.

Results

Two hundred and thirty patients were treated by UGFS and 200 underwent GSV stripping. The 2-year probability of recurrence was similar in the UGFS and surgery groups: 11·3 per cent (24 of 213) and 9·0 per cent (16 of 177) respectively (P = 0·407). At 2 years, reflux irrespective of venous symptoms was significantly more frequent in the UGFS group (35·0 per cent) than in the surgery group (21·0 per cent) (P = 0·003). Mean(s.d.) hospital costs per patient over 2 years were €774(344) per patient for UGFS and €1824(141) for stripping.

Conclusion

At 2-year follow-up, UGFS was not inferior to surgery when reflux associated with venous symptoms was the clinical outcome of interest. UGFS has the potential to be a cost-effective approach to a common health problem. Registration numbers: NCT01103258 (http://www.clinicaltrials.gov) and NTR654 (http://www.trialregister.nl).
Photorealistic cloth in real‐time applications
Authors: Kang Young‐Min , Cho Chang‐Sik
Published: May 2012

In this paper, we propose an efficient and stable animation and rendering method for complex mass‐spring‐based cloth model for interactive applications. Although the mass‐spring model can be easily constructed and simulated, it is well known that the model suffers from the instability problem. The method proposed in this paper employs the harmonic oscillation model and analytically integrates the force for better stability and accuracy while keeping the integration scheme still explicit. As the integration scheme is explicit, the method can be easily parallelized, and the performance improvement can be easily obtained by exploiting the parallelism in the graphics processing unit. For the realistic representation of virtual clothes, we also proposed an efficient and effective rendering method for woven surfaces on the basis of alternating anisotropic reflectance and microfacet distribution function rotation. Copyright © 2012 John Wiley & Sons, Ltd.
ChemInform Abstract: Basic Magnetic Nanoparticles as Efficient Catalysts for the Preparation of Naphthopyran Derivatives.
Authors: Yarahmadi Hossein , Shaterian Hamid Reza
Published: May 2012

The amino‐coated magnetic nanoparticles can be easily recovered by magnetic decantation and reused four times without significant loss of their catalytic activity.
ChemInform Abstract: Highly Effective Synthesis of C‐5‐Substituted 2′‐Deoxyuridine Using Suzuki—Miyaura Cross‐Coupling in Water.
Authors: Sartori Guillaume , Enderlin Gerald , Herve Gwenaelle , Len Christophe
Published: May 2012

Target compounds bearing various aryl groups at the 5‐position are prepared under very low catalyst loadings.
ChemInform Abstract: Emergent Magnetic Monopoles, Disorder, and Avalanches in Artificial Kagome Spin Ice (Invited)
Authors: Huegli R. V. , Duff G. , O'Conchuir B. , Mengotti E. , Heyderman L. J. , Rodriguez A. Fraile , Nolting F. , Braun H. B.
Published: May 2012

Review: 38 refs.
ChemInform Abstract: Efficient H—D Exchange Reactions Using Heterogeneous Platinum‐Group Metal on Carbon—H2—D2O System
Authors: Sawama Yoshinari , Monguchi Yasunari , Sajiki Hironao
Published: May 2012

Review: ca. 100 refs.
ChemInform Abstract: Transition Metal Catalyzed Element—Boryl Additions to Unsaturated Organic Compounds
Authors: Suginome Michinori , Ohmura Toshimichi
Published: May 2012

Review: 143 refs.
Enantioselective sensing of chiral amino alcohols with a stereodynamic arylacetylene‐based probe
Authors: Iwaniuk Daniel P. , Bentley Keith W. , Wolf Christian
Published: May 2012

Enantioselective induced circular dichroism analysis of amino alcohols has been accomplished using a conformationally flexible arylacetylene‐based probe exhibiting two terminal aldehyde groups. The chirality of the amino alcohol substrates is imprinted on the stereodynamic receptor upon [1 + 2] condensation, which ultimately generates a strong chiroptical response. The distinct induced circular dichroism effects of the diimines obtained can be used for enantioselective sensing and enantiomeric excess determination of a wide range of substrates. Chirality 24:584–589, 2012. © 2012 Wiley Periodicals, Inc.
Selectively Guanidinylated Aminoglycosides as Antibiotics
Authors: Fair Richard J. , Hensler Mary E. , Thienphrapa Wdee , Dam Quang N. , Nizet Victor , Tor Yitzhak
Published: May 2012

The emergence of virulent, drug‐resistant bacterial strains coupled with a minimal output of new pharmaceutical agents to combat them makes this a critical time for antibacterial research. Aminoglycosides are a well‐studied, highly potent class of naturally occurring antibiotics with scaffolds amenable to modification, and therefore, they provide an excellent starting point for the development of semisynthetic, next‐generation compounds. To explore the potential of this approach, we synthesized a small library of aminoglycoside derivatives selectively and minimally modified at one or two positions with a guanidine group replacing the corresponding amine or hydroxy functionality. Most guanidino‐aminoglycosides showed increased affinity for the ribosomal decoding rRNA site, the cognate biological target of the natural products, when compared with their parent antibiotics, as measured by an in vitro fluorescence resonance energy transfer (FRET) A‐site binding assay. Additionally, certain analogues showed improved minimum inhibitory concentration (MIC) values against resistant bacterial strains, including methicillin‐resistant Staphylococcus aureus (MRSA). An amikacin derivative holds particular promise with activity greater than or equal to the parent antibiotic in the majority of bacterial strains tested.
Design, Synthesis, and in vitro Antibacterial Activity of Fluoroquinolone Derivatives Containing a Chiral 3‐(Alkoxyimino)‐2‐(aminomethyl)azetidine Moiety
Authors: Lv Kai , Sun Yexin , Sun Lanyin , Wei Zengquan , Guo Huiyuan , Wu Jinwei , Liu Mingliang
Published: May 2012

A series of novel (R)/(S)‐7‐(3‐alkoxyimino‐2‐aminomethyl‐1‐azetidinyl)fluoroquinolone derivatives were synthesized and evaluated for their in vitro antibacterial activity against representative strains. Our results reveal that 12 of the target compounds generally show better activity (MIC: <0.008–0.5 μg mL−1) against the tested Gram‐positive strains including MRSA and MRSE than levofloxacin (LVFX, MIC: 0.125–8 μg mL−1). Their activity is similar to that of gemifloxacin (GMFX, MIC: <0.008–4 μg mL−1). However, they are generally less active than the two reference drugs against Gram‐negative strains. Moreover, against clinical strains of S. aureus including MRSA and S. epidermidis including MRSE, the MIC50 values (0.06–16 μg mL−1) and MIC90 values (0.5–32 μg mL−1) of compounds 16 w, y, and z are 2–8‐ and 2–16‐fold less than LVFX, respectively, and 16 w (MIC90 range: 0.5–4 μg mL−1) was also found to be more active than GMFX (MIC90 range: 1–8 μg mL−1).
The stress birefringence images of low angle grain boundaries in 6H‐SiC single crystals
Authors: Xu Huayong , Gao Yuqiang , Peng Yan , Jiang Kai , Song Sheng , Hu Xiaobo , Xu Xiangang
Published: May 2012

Low angle grain boundaries, also referred to as domain walls, is one of the major structural defects in c‐axis physical vapor transport (PVT) grown hexagonal Silicon Carbide. To investigate the nature of the low angle boundaries, polarized optical microscope was used. The low angle boundary gives bright stress birefringence images under polarizing optical microscope. Periodic extinction of the stress birefringence images occurs when the (0001)‐face SiC is rotated under polarizing optical microscope. The micro‐structure of the low angle boundary is proposed. Using dislocation elastic theory, it is theoretically confirmed that the domains consist of uniform pure edge dislocations with Burgers vectors perpendicular to the dislocation arrays. The simulation results coincide with the experimental observations.
Outbreeding and lack of temporal genetic structure in a drone congregation of the neotropical stingless beeScaptotrigona mexicana
Authors: Mueller Matthias Y. , Moritz Robin F.A. , Kraus F. Bernhard
Published: May 2012

Drone aggregations are a widespread phenomenon in many stingless bee species (Meliponini), but the ultimate and proximate causes for their formation are still not well understood. One adaptive explanation for this phenomenon is the avoidance of inbreeding, which is especially detrimental for stingless bees due to the combined effects of the complementary sex‐determining system and the small effective population size caused by eusociality and monandry. We analyzed the temporal genetic dynamics of a drone aggregation of the stingless beeScaptotrigona mexicanawith microsatellite markers over a time window of four weeks. We estimated the drones of the aggregation to originate from a total of 55 colonies using sibship re‐construction. There was no detectable temporal genetic differentiation or sub‐structuring in the aggregation. Most important, we could exclude all colonies in close proximity of the aggregation as origin of the drones in the aggregation, implicating that they originate from more distant colonies. We conclude that the diverse genetic composition and the distant origin of the drones of theS. mexicanadrone congregation provides an effective mechanism to avoid mating among close relatives.
Design and Synthesis of a Functional Derivative of the Triazinium Cation and Its Rhodium Complex that Shows Photoinduced DNA Cleavage Activity and Photocytotoxicity
Authors: Ghosh Pradip , Sinan Mominul , Lahiri Debojyoti , Roy Sovan , Goswami Sreebrata
Published: May 2012

The design and synthesis of an intensely blue rhodium(III) complex [3]+ of a new N,N‐donor ligand, 8‐(quinolin‐8‐ylamino)pyrido[2,1‐c][1,2,4]benzotriazin‐11‐ium, [2]+, which contains a planar pendant triazinium arm, is described. Structural characterization for [3]+ was carried out by using various spectroscopic techniques and single‐crystal X‐ray crystallography. The organometallic rhodium(III) compound shows a ligand‐based reversible reduction at –0.65 V. The electrochemically reduced compound displays a single‐line EPR spectrum that signifies the formation of ligand‐based free radicals. Compound [3]+ shows a binding propensity to calf thymus DNA to give a Kapp value of 6.05 × 105 M–1. The parent triazinium salt, pyrido[2,1‐c][1,2,4]benzotriazin‐11‐ium [1]+ and the ligand salt [2]+ exhibit photoinduced cleavage of DNA in UV‐A light, whereas the reference Rh complex [3]+ photocleaves DNA with red light (647.1 nm). The compounds show photonuclease activities under both aerobic and anaerobic conditions. Mechanistic investigations under aerobic conditions with several inhibitors indicate the formation of hydroxyl radicals by means of a photoredox pathway. Under anaerobic conditions, it is believed that a photoinduced oxidation of DNA mechanism is operative. Compound [3]+ exhibits photocytotoxicity in HeLa cervical cancer cells to give IC50 values of (12 ± 0.9) μM in UV‐A light at 365 nm and (31.4 ± 1.1) μM in the dark.
Statistical methods for estimating the environmental burden of disease in Canada, with applications to mortality from fine particulate matter
Authors: Almaskut Ahmed , Farrell Patrick J. , Krewski Daniel
Published: May 2012

In this paper, we describe statistical approaches for estimating the burden of disease. Specifically, we present life‐table methods that can be used to determine years of life lost (YLL) due to the disease of interest. In addition, we propose a new variance estimator for the life table based estimator of YLL and demonstrate its accuracy through computer simulation. We also indicate how the population attributable fraction (PAF) of the disease can be calculated in relation to a known risk factor for the disease. The PAF effectively represents the fraction of the disease burden that would be eliminated in the absence of the risk factor of interest. Finally, we illustrate the use of these methods in assessing the PAF for all cause, lung cancer and cardiopulmonary mortality associated with ambient concentrations of fine particulate matter present in ambient air in Canada. Copyright © 2012 John Wiley & Sons, Ltd.
Bedrock versus superficial deposits in the Swiss Jura Mountains: what is the legitimate soil parent material?
Authors: Martignier Loraine , Adatte Thierry , Verrecchia Eric P.
Published: May 2012

Soils are generally considered to be the result of in situ weathered products of geological substrata. Nevertheless, the Earth's surface is mainly composed of superficial deposits made of sediments reworked during periods of climate instability (glaciation, aridification, flooding, etc.). But to what extent do these deposits influence present‐day soil development and/or lessen the contribution of the geological substratum? In the Swiss Jura Mountains, characterization and distribution of superficial deposits along a toposequence are used in order to decipher the polygenic sources of soil parent materials and question the importance of lithodependence in soil development. The in situ weathering material and the allochtonous deposits are discriminated through analysis of mineralogical composition, grain size distribution of the soil mineral fraction, and multivariate statistical treatment. As expected, calcite is dominant in the autochonous mineral phase, leading to high pH values in deep soil layers. However, the mineralogical composition of the surficial deposits is made of local mineral components mixed with allochtonous aeolian deposits. This exogenous material is dominated by quartz and phyllosilicates, and is reflected by low pH values in soil surficial horizons. The grain size distribution curves of the insoluble residue from bedrocks are unimodal and dominated by fine loam and clays. In contrast, surficial deposits display polymodal curves, demonstrating the contribution of various aeolian episodes and/or sources. Analysis of the surface texture of quartz sand grains shows glacial marks intersected by aeolian shock marks, indicating the posteriority of wind transportation. Loess material originates from Alpine moraines of the Swiss Plateau and is mixed with deposits originating from more proximal Jura moraines, diluting the Alpine signature. Consequently, the soil development does not follow the expected and conventional decalcification process, but is directly influenced by the origin of the primary sediments (even when present only in small amounts) and their evolution. Copyright © 2012 John Wiley & Sons, Ltd.
Measuring bioconcentration factors in fish using exposure to multiple chemicals and internal benchmarking to correct for growth dilution
Authors: Adolfsson-Erici Margaretha , Åkerman Gun , McLachlan Michael S.
Published: May 2012

Modern chemical legislation requires measuring the bioconcentration factor (BCF) of large numbers of chemicals in fish. The BCF must be corrected for growth dilution, because fish growth rates vary between laboratories. Two hypotheses were tested: (1) that BCFs of multiple chemicals can be measured simultaneously in one experiment, and (2) that internal benchmarking using a conservative test substance in the chemical mixture can be used to correct for growth dilution. Bioconcentration experiments were conducted following major elements of the OECD 305 guideline. Fish were simultaneously exposed to 11 chemicals selected to cover a range of BCFs and susceptibility to biotransformation. A method was developed to calculate the growth-corrected elimination rate constant from the concentration ratio of the analyte and a benchmarking chemical for which growth dilution dominated other elimination mechanisms. This method was applied to the experimental data using hexachlorobenzene as the benchmarking chemical. The growth dilution correction lowered the apparent elimination rate constants by between 5% and a factor of four for eight chemicals, while for two chemicals the growth-corrected elimination rate constant was not significantly different from zero. The benchmarking method reduced the uncertainty in the elimination rate constant compared to the existing method for growth dilution correction. The BCFs from exposing fish to 10 chemicals at once were consistent with BCF values from single-chemical exposures from the literature, supporting hypothesis 1. Environ. Toxicol. Chem. 2012; 31: 1853–1860. © 2012 SETAC
Physiological analysis of silver nanoparticles and AgNO3 toxicity to Spirodela polyrhiza
Authors: Jiang Hong-Sheng , Li Ming , Chang Feng-Yi , Li Wei , Yin Li-Yan
Published: May 2012

Silver nanoparticles (AgNPs) are commonly used in consumer products for their antibacterial activity. Silver nanoparticles may adversely influence organisms when released into the environment. The present study investigated the effect of AgNPs on the growth, morphology, and physiology of the aquatic plant duckweed (Spirodela polyrhiza). The toxicity of AgNPs and AgNO3 was also compared. The results showed that silver content in plant tissue increased significantly with higher concentrations of AgNPs and AgNO3. Silver nanoparticles and AgNO3 significantly decreased plant biomass, caused colonies of S. polyrhiza to disintegrate, and also resulted in root abscission. Physiological analysis showed that AgNPs and AgNO3 significantly decreased plant tissue nitrate–nitrogen content, chlorophyll a (Chl a) content, chlorophyll a/b (Chl a/b), and chlorophyll fluorescence (Fv/Fm). Changes in soluble carbohydrate and proline content were also detected after both AgNO3 and AgNPs treatment. However, after 192 h of recovery, total chlorophyll content increased, and Fv/Fm returned to control level. Median effective concentration (EC50) values for Chl a and phosphate content showed that AgNO3 was more toxic than AgNPs (EC50 values: 16.10 ± 0.75 vs 7.96 ± 0.81 and 17.33 ± 4.47 vs 9.14 ± 2.89 mg Ag L−1, respectively), whereas dry-weight EC50 values showed that AgNPs were more toxic than AgNO3 (13.39 ± 1.06 vs 17.67 ± 1.16 mg Ag L−1). Environ. Toxicol. Chem. 2012; 31: 1880–1886. © 2012 SETAC
Contaminant residues and declines of the Cascades frog (Rana cascadae) in the California Cascades, USA
Authors: Davidson Carlos , Stanley Kerri , Simonich Staci Massey
Published: May 2012

Populations of Cascades frogs (Rana cascadae) have declined precipitously in the Mount Lassen area, but remain abundant in the other half of their California range in the Klamath Mountains. To evaluate the role of contaminants in Cascade frog declines, we sampled sediment and frog tadpole tissue at 31 sites where Cascades frogs had disappeared and sites where Cascades frogs are still present across the Lassen and Klamath regions. Pacific chorus frogs (Pseudacris regilla) were tested and used as surrogates for residue concentrations in Cascades frogs. We analyzed a total of 79 tadpole samples for 73 semivolatile contaminants including pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The most frequently detected residue was endosulfan sulfate, followed by dacthal, chlorpyrifos, PCB 187, endosulfan II, trans-chlordane, and trans-nonachlor. Chorus frogs had similar residue concentrations as Cascades frogs for most but not all chemicals, indicating that chorus frogs can serve as a reasonable proxy for chemical concentrations in Cascades frogs. None of the contaminants in tissue or sediment had significantly higher concentrations at sites where Cascades frogs have disappeared than at sites where Cascades frogs are still present. We found no evidence to support the hypothesis that the contaminants analyzed have contributed to the decline of Cascades frogs in northern California, although we were able to analyze only a handful of the over 300 pesticides currently used in the area. Environ. Toxicol. Chem. 2012; 31: 1895–1902. © 2012 SETAC
Linking HRM and knowledge transfer via individual‐level mechanisms
Authors: Minbaeva Dana B. , Mäkelä Kristiina , Rabbiosi Larissa
Published: May 2012

In response to recent calls for more research on micro‐foundations, we seek to link human resource management (HRM) and knowledge transfer through individual‐level mechanisms, arguing that individual‐level conditions of action influence the extent to which employees engage in knowledge exchange. We examine four such conditions empirically using data from 811 employees in three Danish multinational corporations (MNCs). Our findings suggest that individual‐level perceptions of organizational commitment to knowledge sharing, and extrinsic motivation, directly influence the extent to which employees engage in firm‐internal knowledge exchange. We also find that intrinsic motivation and engagement in social interaction significantly mediate the relationship between perceived organizational commitment and knowledge exchange. Given that HRM can influence such conditions through an overall signaling effect and various practices, an understanding of these micro‐foundations will shed light on how organizations can effectively enhance knowledge transfer through HRM. © 2012 Wiley Periodicals, Inc.
Sleep Quality as a Potential Mediator Between Psychological Distress and Diabetes Quality of Life in Veterans With Type 2 Diabetes
Authors: Seligowski Antonia V. , Pless Kaiser Anica P. , Niles Barbara L. , Mori DeAnna L. , King Lynda A. , King Daniel W.
Published: May 2012

Objective

The goal of this study was to explore sleep quality as a potential mediator between depression symptoms and diabetes quality of life (DQOL), and anxiety symptoms and DQOL.

Method

Participants were 83 male and 3 female veterans with type 2 diabetes (Mage = 62.4). Self‐report measures were completed during the baseline assessment of a larger intervention study conducted at the VA Boston Healthcare System.

Results

Depression symptoms, anxiety symptoms, and sleep quality were all associated with DQOL. Additionally, sleep quality had a partial indirect effect on the relationships between depression symptoms and DQOL, and between anxiety symptoms and DQOL.

Conclusions

These findings suggest that sleep quality may have an important role in the way that psychological distress affects diabetes quality of life. © 2012 Wiley Periodicals, Inc. J. Clin. Psychol. 00:1‐11, 2012.
Cytochemical investigation of the digestive gland of two strombidae species (Strombus gigas and Strombus pugilis) in relation to the nutrition
Authors: Volland Jean‐Marie , Gros Olivier
Published: May 2012

Strombus gigas and Strombus pugilis are threatened species and aquaculture represents a good alternative solution to the fishing. In this study, we highlighted the intracellular digestion process in the digestive gland of two Strombidae species, S. gigas and Strombuspugilis, by the cytochemical characterization of two lysosomal enzymes: acid phosphatase and arylsulfatase. In order to check the efficiency of artificial food digestion, we conducted the characterization on freshly collected, starved and artificially fed individuals of S. pugilis. TEM observations of digestive gland sections from freshly collected individuals of both species revealed the presence of acid phosphatase and arylsulfatase activity mostly located in the apical third of digestive cells. Both enzymes were also detected in artificially fed individuals. In response to the starvation, acid phosphatase is not produced anymore by digestive cells, while arylsulfatase is still present. To our knowledge, this is the first cytochemical validation of intracellular digestion of artificial food in Strombidae. This study highlights the intracellular digestion of artificial food developed for Strombidae aquaculture. Moreover, we have shown that the lysosomal activity could be used as a feed index. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.
Clinical factors predicting readmission after orthotopic liver transplantation
Authors: Pereira Arema A. , Bhattacharya Renuka , Carithers Robert , Reyes Jorge , Perkins James
Published: May 2012

Hospitals with the highest readmission rates for high-cost conditions may be targeted for payment penalties. The primary aim of this study was to determine clinical predictors of 30-day readmission after discharge for patients undergoing orthotopic liver transplantation (OLT) at the University of Washington from January 2003 to October 2010. Secondary aims included the determination of predictors of institutional care after OLT and differences in survival between patients requiring 30-day readmission and patients not requiring 30-day readmission. Sixty-five of 766 discharged OLT patients (8.6%) required institutional care on discharge; 318 of the 701 remaining patients (45%) were readmitted within 30 days. The predictors of readmission included hospitalization within the 90 days before OLT [29.6% versus 18.4%, relative risk (RR) = 1.33, P = 0.04], pre-OLT portal vein thrombosis (7.9% versus 4.4%, RR = 1.76, P = 0.01), a creatinine level > 1.9 mg/dL (23.9% versus 11.5%, RR = 2.1, P ≤ 0.01), an albumin level < 2.6 mg/dL (51.9% versus 37.6%, RR = 1.57, P < 0.01), postoperative complications (38.7% versus 30.2%, RR = 1.31, P = 0.04), and a high school education or less (14.5% versus 10%, RR = 1.41, P = 0.04). One year after OLT, decreased survival was found for patients requiring 30-day readmission versus patients not requiring readmission (88.2% versus 95.6%, P < 0.05). In conclusion, this study has identified patients at high risk of readmission who may benefit from medical optimization. Liver Transpl, 2012. © 2012 AASLD.
Differentiation and assignment of vinyl telluride regioisomers by 1H‐125Te gHMBC
Authors: Freitas Juliano C. R. , Palmeira Dayvson J. , Oliveira Roberta A. , Menezes Paulo H. , Silva Ricardo O.
Published: May 2012

Complete 1H, 13C, and 125Te NMR spectral data for some vinyl tellurides are described. The 1H–125Te gHMBC experiment was used for the complete chemical shift assignment and structure elucidation of a mixture of regioisomers. The assignment (125Te NMR) and coupling constants (JH,H) for all regioisomers are described for the first time. Copyright © 2012 John Wiley & Sons, Ltd.
Hyperbranched polyimide application in liquid crystal alignment layers
Authors: Sun Zhen , Wang Yinghan
Published: May 2012

Several hyperbranched polyimides (HBPIs) were applied in liquid crystal (LC) alignment layers and exhibited outstanding performance for LC alignment. The maximum pretilt angle was above 8°, and the minimum pretilt angle was 4.2°. The results of atomic force microscope measurement disclosed that a lot of grooves were aligned parallel to the rubbing direction and found that the grooves were not main factor for LC alignment. The LC alignment and pretilt angles are unambiguously associated with the intrinsic HBPI chemical structures. The results of thermal gravimetric analysis and ultraviolet–visible spectra showed that the HBPIs had good thermal stability and excellent transmittance. T5 and T10 were higher than 360°C and 400°C, respectively. Copyright © 2012 John Wiley & Sons, Ltd.