bluuebunny/crossref_metadata_2025 huggingface dataset:
Neue taxonomische Erkenntnisse zu den Charakterarten der Schwermetallvegetation und mögliche Konsequenzen für den Schutz von Schwermetallstandorten
Authors: Baumbach H. , Schubert R.
Published: October 2008

Schwermetallstandorte gehören zu den in ökologischer Hinsicht besonders interessanten Lebensräumen Mitteleuropas. Sie sind deshalb nach der FFH‐Richtlinie, Anhang I, geschützt (Lebensraumtyp 6130) und gehören zu den nach § 30 BNatSchG besonders geschützten Biotoptypen. Neue wissenschaftliche Erkenntnisse zur genetischen Differenzierung der Charakterarten der Schwermetallvegetation (z. B.Minuartia verna,Silene vulgaris,Armeria maritimas. l.,Viola calaminaria,Cardaminopsis halleri,Thlaspi caerulescens) haben gezeigt, dass taxonomische Neubewertungen erforderlich sind, die auch Änderungen der Syntaxonomie der Schwermetallpflanzengesellschaften nach sich ziehen werden. Wie die auf botanische Aspekte fokussierte (behördliche) Naturschutzpraxis zeigt, können sich daraus nicht unerhebliche Probleme für die Definition des Lebensraumtyps ergeben. Der Beitrag thematisiert diese Problematik und möchte mögliche Konsequenzen für den Schutz der Schwermetalllebensräume diskutieren. Trotz des gesetzlichen Schutzes und vielfältiger Schutzbemühungen ist in mehreren Regionen nach wie vor ein Rückgang der Schwermetalllebensräume festzustellen, dessen Ursachen exemplarisch für die Standorte im östlichen und südöstlichen Harzvorland (Sachsen‐Anhalt) aufgezeigt werden. Die erörterten grundsätzlichen Probleme betreffen jedoch alle Gebiete in Mitteleuropa, in denen Lebensgemeinschaften auf metallhaltigen Böden vorkommen. Ziel des Beitrages ist es, eine regionale Schutzkonzeption für die mitteldeutschen sowie eine überregionale Schutzkonzeption für die mitteleuropäischen Schwermetalllebensräume anzuregen und deren wichtigste Aspekte aufzuzeigen. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rock and scree plant communities in the Serra de Monchique (SW Portugal)
Authors: Deil U. , de Mera A. Galán , Orellana J. A. Vicente
Published: October 2008

The vegetation of rock and scree habitats in the Serra de Monchique, a mountain range of mid altitude in the hinterland of the Algarve has been studied to see which plant communities grow in relation to substrate, altitude, aspect and micro‐relief. The associations are discussed in a West Mediterranean context.

The Serra is a humid outpost in Southern Portugal. Rock habitats exist in the central part on syenite, a bedrock material with high base saturation. Weathering results in rock outcrops, poor in fissures, and in consolidated boulders and sandy soils. The central part is surrounded by schist, graywakes and sandstones, offering rock and scree habitats. New associations described are the rock heathland Halimio calycini‐Ericetum australis, the Sileno melliferae‐Ranunculetum bupleuroides on boulders, a Margotia gummifera ‐Iris xiphium ‐rock pasture and the Mucizonio hispidae‐Cheilanthetum tinaei in shaded fissures. The following associations are first documented for the area: Anogrammo‐Umbilicetum rupestris (on humid terrace walls), the Sedo hirsuti‐Polypodietum cambrici (humid rock surfaces in higher regions), the Asplenio ceterach‐Cheilanthetum acrostichae (rock fissures) and the Phagnalo saxatilis‐Rumicetum indurati (on screes). Rumex induratus occurs together with Dittrichia revoluta as an apophyte on road embankments and colonizes, with Scrophularia frutescens, riverine gravel.

In contrast to rock communities on limestone and dolomite in the Algarve lowland and the hotspot of endemism at Cabo São Vicente, no endemic rock species occur in the Serra de Monchique. The vegetation mosaic on the syenite outcrops however is unique and deserves high priority in nature conservation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling and forecasting time series sampled at different frequencies
Authors: Casals José , Jerez Miguel , Sotoca Sonia
Published: October 2008

This paper discusses how to specify an observable high‐frequency model for a vector of time series sampled at high and low frequencies. To this end we first study how aggregation over time affects both the dynamic components of a time series and their observability, in a multivariate linear framework. We find that the basic dynamic components remain unchanged but some of them, mainly those related to the seasonal structure, become unobservable. Building on these results, we propose a structured specification method built on the idea that the models relating the variables in high and low sampling frequencies should be mutually consistent. After specifying a consistent and observable high‐frequency model, standard state‐space techniques provide an adequate framework for estimation, diagnostic checking, data interpolation and forecasting. An example using national accounting data illustrates the practical application of this method. Copyright © 2008 John Wiley & Sons, Ltd.
Activation of Src and Src‐associated signaling pathways in relation to hypoxia in human cancer xenograft models
Authors: Pham Nhu‐An , Magalhaes Joao M.M.M. , Do Trevor , Schwock Joerg , Dhani Neesha , Cao Ping‐Jiang , Hill Richard P. , Hedley David W.
Published: October 2008

The hypoxic response in vitro involves alterations in signaling proteins, including Src, STAT3 and AKT that are considered to be broadly pro‐survival. The involvement of these signaling proteins in the hypoxic microenviroments that occur in solid tumors was investigated by the use of multicolor fluorescence image analysis to colocalize signaling proteins and regions of hypoxia in 4 human tumor xenografts, pancreatic carcinoma BxPC3 and PANC1 and cervical squamous cell carcinoma ME180 and SiHa. Expression levels of total Src protein (mean intensity × labeled region fraction) were higher in hypoxic regions, identified using the nitroimidazole probe EF5, relative to non‐EF5 regions in all 4 tumor models. This was associated with higher levels of phosphorylated (p‐) Y419p‐Src and its substrate Y861p‐FAK in EF5 positive regions of BxPC3 tumors. This effect was also seen in tumor‐bearing mice continuously breathing 7% oxygen for 3 hr which markedly increased the extent of EF5 positive labeling. In contrast, the hypoxia treatment resulted in a significant decrease in S727p‐STAT3 in BxPC3 xenografts and suggested that STAT3 activity is responsive to acute hypoxia, whereas Src‐FAK signaling is associated with predominantly chronically hypoxic EF5 positive regions. Src activity in both hypoxic and nonhypoxic BxPC3 tumor regions was suppressed when mice were treated with the Src inhibitor AZD0530 (25 mg/kg/day, 5 days), suggesting that both hypoxic and normoxic tumor regions are accessible to pharmacological Src inhibition. These results show that signaling pathways are responsive to tumor hypoxia in vivo, although the effects appear to differ between individual tumor types. © 2008 Wiley‐Liss, Inc.
How Views about Flow Adaptations of Benthic Stream Invertebrates Changed over the Last Century
Authors: Statzner Bernhard
Published: October 2008

Throughout the last century, stream ecologists tried to answer the question: how do benthic invertebrates cope with the flows prevailing in streams? Whereas the pioneers frequently sought answers using imagination and speculation in a hefty debate, subsequent research on flow adaptations of stream invertebrates relied increasingly on the transfer of concepts (from fluid mechanics to stream ecology) and technological innovations. Correspondingly, views about flow adaptations of stream invertebrates changed considerably over the last century. However, stream ecologists are still far from understanding how stream invertebrates are adapted to the many different flow conditions they face during their life, because the near‐bottom flows they experience are extremely complex and create so diverse constraints that adaptation to all of them is physically impossible.

This instance shows how ignorant we are of the physical factors in the environment which ultimately shape the organisms, and how difficult it is to understand the utility of a structure without knowing the requirements for which it is produced

Sunder Lal Hora, 1930 (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aquatic Microbial Ecology: Water Desert, Microcosm, Ecosystem. What's Next?
Authors: Psenner Roland , Alfreider Albin , Schwarz Astrid
Published: October 2008

Aquatic microbial ecology aims at nothing less than explaining the world from “ecological scratch”. It develops theories, concepts and models about the small and invisible living world that is at the bottom of every macroscopic aquatic system. In this paper we propose to look at the development of Aquatic Microbial Ecology as a reiteration of classical (eukaryotic) limnology and oceanography. This was conceptualized moving historically from the so‐called water desert to microcosm to ecosystem. Each of these concepts characterizes a particular historical field of knowledge that embraces also practices and theories about living beings in aquatic environments. Concerning the question of “who is there”, however, Aquatic Microbial Ecology historically developed in reverse order. Repetition, reiteration and replication notwithstanding, Aquatic Microbial Ecology has contributed new ideas, theories and methods to the whole field of ecology as well as to microbiology. The disciplining of Aquatic Microbial Ecology happened in the larger field of plankton biology, and it is still attached to this biological domain, even conceiving of itself very self‐consciously as a discipline of its own. Today, Aquatic Microbial Ecology as a discipline is much broader than plankton ecology ever was, for it includes not only oceans and freshwaters but also benthic, interstitial and groundwater systems. The success of Aquatic Microbial Ecology is expressed by its influence on other fields in ecology. The challenge is to further develop its theoretical and methodological features while at the same time contributing to current pressing problems such as climate change or the management of global water resources.

And then it may not be fanciful to suppose that even in the year nineteen hundred and nineteen a great number of minds are still only partially lit up by the cold light of knowledge. It is the most capricious illuminant. They are still apt to ruminate, without an overpowering bias to the truth, whether a kingfisher's body shows which way the wind blows; whether an ostrich digests iron; whether owls and ravens herald ill‐fortune; and the spilling of salt bad luck; what the tingling of ears forebodes, and even to toy pleasantly with more curious speculations as to the joints of elephants and the politics of storks, which came within the province of the more fertile and better‐informed brain of the author (1919)

Virginia Woolf from the essay “Reading”, In: Leonard Woolf (ed.), 1950: The Captain's Death Bed and Other Essays, – London: Hogarth Press, p. 157. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Changing Paradigms in Groundwater Ecology – from the ‘Living Fossils' Tradition to the ‘New Groundwater Ecology’
Authors: Danielopol Dan Luca , Griebler Christian
Published: October 2008

Groundwater ecology merged during the second part of the 20th century with modern ecological practice after having adopted the ‘ecosystem concept’. The latter was first applied to karstic systems and separately for alluvial non‐consolidated aquifers along surface running waters. Today groundwater ecosystems are studied within a multi‐ and transdisciplinary framework at various spatial and temporal scales by experts dealing with microbiology, the ecology and systematics of meio‐ and macro‐fauna, geochemistry, hydrogeology and mathematical modelling. A further paradigmatic change occured with the recognition that subterranean assemblages of organisms are formed by both hypogean and epigean taxa. The biological diversity in subterranean ecosystems can be much higher than earlier thought and may even exceed surface diversity in some taxa. This largely unrecognized biodiversity in many cases deserves environmental protection. A third phase in the development of groundwater ecology has occured over the last 15 years with the incorporation of socio‐economic research topics within groundwater ecology (Gibert et al., 1994a) and in this sense today we have the “New Groundwater Ecology”.

We should cling to our traditions and do what we can to keep the understanding of the world in which we live as a resource for all humankind

Colin S. Reynolds, 2001: Limnology in the New Century: 21 Topics for Research. – Limnology 1, p. 17 (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Daphnia Paleogenetics and Environmental Change: Deconstructing the Evolution of Plasticity
Authors: Hairston Nelson G. , Meester Luc De
Published: October 2008

It is only recently that ecologists, including limnologists, have begun to appreciate the potential for organisms to evolve rapidly in response to environmental change. The resulting changes in the mean characteristics of the evolving populations have the potential to alter population, community and ecosystem responses to environmental changes – while those changes are still taking place. Viable diapausing eggs of zooplankton buried annually in lake sediments represent an historical record of the genotypes present at a series of time points in the past, typically dating back several decades. Because these eggs can be extracted from sediment layers of known age and hatched, the phenotypes of past populations can be reconstructed and evolutionary responses to recent environmental change revealed. This is especially valuable for investigating the nature of evolution of phenotypically plastic traits for which trait expression in different environmental conditions must be measured using living animals. When animals, hatched from sediments deposited at different times during a period of rapid change in the lake environment, are reared under a range of laboratory conditions, the nature of plasticity evolution can be discovered. Here, we use the results of two previously published studies of Daphnia evolutionary response to anthropogenic environmental change to deconstruct the patterns and rates of genetic changes in phenotypic plasticity. We find for the populations studied that (1) in three of four instances, plasticity evolved primarily by changes in the trait expressed in the environmental condition for which selection acted most strongly, rather than purely as a change in slope, and (2) the rates of evolution of plasticity were comparable to those for constitutive traits reported in the literature suggesting that plasticity does not necessarily retard the rate of evolution. Because Daphnia is a critical species in many limnetic ecosystems, and because in both of our study systems the characteristics of the Daphnia populations that evolved are known to influence community and ecosystem processes, this rapid adaptive evolution may be a critical component of population, community and ecosystem response to the accelerating pace of environmental change.

Plus ça change, plus c'est la même chose

Jean‐Baptists Alphonse Karr, Les Guêpes, January 1849 (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modulation of host cell mechanics by Trypanosoma cruzi
Authors: Mott Adam , Lenormand Guillaume , Costales Jaime , Fredberg Jeffrey J. , Burleigh Barbara A.
Published: October 2008

To investigate the effects of Trypanosoma cruzi on the mechanical properties of infected host cells, cytoskeletal stiffness and remodeling dynamics were measured in parasite‐infected fibroblasts. We find that cell stiffness decreases in a time‐dependent fashion in T. cruzi‐infected human foreskin fibroblasts without a significant change in the dynamics of cytoskeletal remodeling. In contrast, cells exposed to T. cruzi secreted/released components become significantly stiffer within 2 h of exposure and exhibit increased remodeling dynamics. These findings represent the first direct mechanical data to suggest a physical picture in which an intact, stiff, and rapidly remodeling cytoskeleton facilitates early stages of T. cruzi invasion and parasite retention, followed by subsequent softening and disassembly of the cytoskeleton to accommodate intracellular replication of parasites. We further suggest that these changes occur through protein kinase A and inhibition of the Rho/Rho kinase signaling pathway. In the context of tissue infection, changes in host cell mechanics could adversely affect the function of the infected organs, and may play an important role on the pathophysiology of Chagas' disease. J. Cell. Physiol. 218: 315–322, 2009. © 2008 Wiley‐Liss, Inc.
Effects of apple and pear varieties and pH on patulin accumulation by Penicillium expansum
Authors: Morales Hèctor , Barros Germán , Marín Sonia , Chulze Sofía , Ramos Antonio J , Sanchis Vicente
Published: October 2008

BACKGROUND: Accumulation of patulin in apples and pears and subsequently in their by‐products is caused mostly by Penicillium expansum which causes blue mould. Fruit pH and other parameters are sometimes characteristic of a certain variety and thus the use of particular varieties might affect patulin content in the final products. The aim of this study was to evaluate the influence of fruit variety and pH on patulin accumulation. Patulin accumulation in both apple and pear juices at different pH and also in different apple varieties (Golden, Gala and Fuji) and pear varieties (Blanquilla and Conference) was assessed.

RESULTS: The pH of juices significantly influenced patulin accumulation, especially in apple juice in which the highest amounts of patulin were detected at pH 3.5. In fruits, the pH values of the substrate were determinant only under cold storage. Thus, Golden apples, which presented a lower pH, accumulated more patulin at 1 °C. However, this trend was not observed at other temperatures in which varieties with higher amounts of organic acids (Golden and Fuji apples) accumulated most patulin. In the pear varieties, significant differences in pH did not lead to significant differences in patulin accumulation.

CONCLUSION: Although pH influences patulin accumulation, other factors such as organic acid content may play an important role. Concerning the apple and pear varieties we studied, it seems that rather than variety, other parameters like pH or acidic content may be more important. These parameters vary significantly depending on the degree of ripeness of the fruit. Gala apple, which is used in Spanish juice production, was the only variety that accumulated dramatically higher amounts of patulin. Copyright © 2008 Society of Chemical Industry
Flows into tourist areas: an econometric approach
Authors: Torraleja Félix‐Angel Grande , Vázquez Agustín Muñoz , Franco María José Botella
Published: October 2008

The globalisation of the tourism industry has led to a horizontal and vertical penetration of firms, leading to strong competition in all tourist centres. In light of these circumstances there is a need to develop strategies that encourage entrepreneurial actions and help firms to design the most competitive tourism offer possible. For the development of these strategies, the current work attempts to identify the degree of interrelation existing between the different tourist markets. Specifically, the study is based on an analysis of the evolution in the relations between the main tourist‐receiving centres in Spain. It identifies the short‐ and long‐term dynamic relations existing between them, and determines their degree of interdependence and any potential leadership relations between them. The methodology used is the one underlying Cointegration theory and vector autoregressive theory, together with forecast error variance decomposition and the impulse‐response function. Copyright © 2008 John Wiley & Sons, Ltd.
Supply chain in tourism destinations: the case of Levi Resort in Finnish Lapland
Authors: Rusko Rauno Tapio , Kylänen Mika , Saari Rükka
Published: October 2008

Tourism destinations in Finnish Lapland provide a suitable base for supply chain management (SCM). Often, the investments in these destinations are directed to wilderness areas without significant initial infrastructure. Thus, the surroundings provide better possibilities to build and direct the experiences of tourists in contrast to city tourism where the surroundings are not especially designed for tourism. In this paper we apply an SCM framework to the Levi Fell resort in northern Finland. By identifying some special characteristics of tourism destinations and region‐based tourism production, we further develop the traditional SCM framework in the context of tourism. Copyright © 2008 John Wiley & Sons, Ltd.
Online and off‐line travel packages preferences: a conjoint analysis
Authors: Chiam Michael , Soutar Geoffrey , Yeo Alvin
Published: October 2008

Past research has suggested that a number of travel package attributes impact on people's choices. In the present study the impacts of a number of these elements (price, package characteristics, travel agents and a seal of approval) in online and off‐line environments were examined using conjoint analysis. It was found that price had the biggest impact, although travel agent and airline reputation and trustworthiness also impacted on people's preferences. Interestingly, there were no significant differences in the attributes' impacts in the online and off‐line environments. Copyright © 2008 John Wiley & Sons, Ltd.
An economic impact analysis of the Korean exhibition industry
Authors: Kim Samuel Seongseop , Chon Kaye
Published: October 2008

This study estimates the multiplier effect of the exhibition industry. In order to calculate the exhibition industry's total expenditure, consideration is made of three major sources of expenditure including hosts, exhibitors and foreign attendees. According to the summary of the economic impact analysis, the total exhibition receipts of US$645.7 million produced US$1.2 billion in output; 21 692 full‐time equivalent jobs, US$260 million in personal income for residents, US$577.4 million in value‐added, US$54.2 million in indirect tax and US$104.3 million in imports. Copyright © 2008 John Wiley & Sons, Ltd.
Tourism and national identity in Uganda
Authors: Lepp Andrew , Harris John
Published: October 2008

Over the last decade, international tourism has grown rapidly in Uganda. This has been planned by a small consortium of tourism officials working with the central government. Through data obtained from interviews with Ugandan tourism officials, this paper critically assesses their understandings of tourism's role in Uganda's development. Officials conceptualise tourism as a means of constructing a positive national identity for foreign consumption, and hope that a positive national identity abroad will increase foreign investment and spark development. This research considers (re)presentations of the nation and the way(s) in which Uganda is being developed as a tourist destination. Copyright © 2008 John Wiley & Sons, Ltd.
The destination‐management organisation and the integrative destination‐marketing process
Authors: Elbe Jörgen , Hallén Lars , Axelsson Björn
Published: October 2008

A main function of destination‐management organisations (DMOs) is that of being responsible for marketing their destinations. Many destinations involve stakeholders of different kinds. DMOs often have modest resources, and this creates a challenge: how should the DMO manage their marketing activities and achieve an outcome that benefits both the individual stakeholder and the destination? This study describes how DMOs can mobilise resources among the stakeholders and identifies the processes leading to integrated destination marketing. Basing our conclusions on a case study, we find that DMOs need to develop both pragmatic and moral legitimacy in order to develop integrated destination marketing. Copyright © 2008 John Wiley & Sons, Ltd.
Layer‐by‐Layer Buildup of Poly(L‐glutamic acid)/Chitosan Film for Biologically Active Coating
Authors: Song Zhijiang , Yin Jingbo , Luo Kun , Zheng Yanzhen , Yang Yan , Li Qiong , Yan Shifeng , Chen Xuesi
Published: October 2008

A new biocompatible film based on chitosan and poly(L‐glutamic acid) (CS/PGA), created by alternate deposition of CS and PGA, was investigated. FT‐IR spectroscopy, UV‐vis spectroscopy and QCM were used to analyze the build‐up process. The growth of CS and PGA deposition are both exponential to the deposition steps at first. After about 9 (CS/PGA) depositions, the exponential to linear transition takes place. QCM measurements combined with UV‐vis spectra revealed the increase in the multilayer film growth at different pH (4.4, 5.0 and 5.5). The build‐up of the multilayer stops after a few depositions at pH = 6.5. A muscle myoblast cell (C2C12) assay showed that (CS/PGA)n multilayer films obviously promote C2C12 attachment and growth.

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Self‐Assembling Diblock Copolymers of Poly[N‐(2‐hydroxypropyl)methacrylamide] and a β‐Sheet Peptide
Authors: Radu Larisa Cristina , Yang Jiyuan , Kopeček Jindřich
Published: October 2008

The self‐assembly of hybrid diblock copolymers composed of poly(HPMA) and β‐sheet peptide P11 (CH3CO‐QQRFQWQFEQQ‐NH2) blocks was investigated. Copolymers were synthesized via thiol‐maleimide coupling reaction, by conjugation of semitelechelic poly(HPMA)‐SH with maleimide‐modified β‐sheet peptide. As expected, CD and CR binding studies showed that the peptide block imposed its β‐sheet structural arrangement on the structure of diblock copolymers. TEM and AFM proved that peptide and these copolymers had the ability to self‐assemble into fibrils.

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Macromol. Chem. Phys. 20/2008
Authors: Gaborieau Marianne , Graf Robert , Spiess Hans Wolfgang
Published: October 2008

Cover: Local nanophase separation in melts of polymers with side chains was determined using recently developed NMR techniques. Poly(n‐alkyl methacrylates) exhibit a higher local anisotropy of the main chain motions and a more pronouced nanophase separation than poly(n‐alkyl acrylates). Further details can be found in the article by M. Gaborieau,* R. Graf, and H. W. Spiess* on page 2078.
Hybrid Compound Block Copolymer Micelles Encapsulating Gold Nanoparticles
Authors: Mantzaridis Christos , Pispas Stergios
Published: October 2008

We report here on the formation of hybrid compound block copolymer micelles encapsulating gold nanoparticles, utilizing a direct and general preparation method. The giant hybrid compound micelles are structured with micelles of PS‐b‐P2VP with gold nanoparticles in their P2VP core and PI‐b‐PS chains as the outer part of the compound micelles. The gold nanoparticles were produced using gold ion‐loaded PS‐b‐P2VP micelles as a nanoreactor, in a PS selective solvent (toluene), by the subsequent reduction of gold ions. The synthesis of the gold nanoparticles was monitored by UV‐vis spectroscopy. The gold containing micelles were then encapsulated in larger micelles of PI‐b‐PS copolymer, by successive utilization of toluene and heptane with the intermediate evaporation of toluene. The nanoassembly of the compound materials comprised a PI corona and a PS compound core, with P2VP/Au0 domains, and was characterized using UV‐vis spectroscopy, dynamic light scattering and transmission electron microscopy.

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Sensitivity of the LHN scheme to non‐rain echoes
Authors: Rossa Andrea , Leuenberger Daniel
Published: October 2008

Radar‐derived quantitative precipitation estimates (QPE) are becoming an increasingly important element in high‐resolution numerical weather prediction (NWP). As such they complement conventional data like surface or upper‐air observations. Unlike the latter, radar data exhibit a highly variable quality, in that they are affected by a number of factors that limit their accuracy in estimating precipitation at the surface. In the context of assimilating radar‐derived QPE in high‐resolution NWP models this poses two salient questions, i.e. how is a specific assimilation scheme affected by errors in the observations, and how can such variable quality be accounted for?

This paper addresses the first question and presents a sensitivity study of the Latent Heat Nudging (LHN) scheme in a meso‐gamma scale NWP model to gross errors in the radar data, notably non‐rain echoes. It was found that non‐rain, or clutter, echoes as small as one model pixel can trigger the release of convective instabilities when forced by the LHN scheme, producing model precipitation that is large compared to the original non‐rain signal. Enhancement factors from 3 up to 50 have been found for moderate to high values of CAPE and low to medium intensity clutter signals. Furthermore, the response of the model atmosphere to the forcing was found to be very quick, i.e. on the time scale of convection (less than 10 min for strong forcing to a couple of hours for moderate forcing). Large coherent areas of non‐rain echoes were found to be more likely to initiate such erroneous precipitation enhancement than scattered gridbox‐sized signals. Finally, non‐rain echoes resulting from anomalous propagation of the radar beam, by virtue of the usually very stable conditions with which they are associated, are not very conducive to rainfall amplification. However, a strong spurious vertical circulation, along with undesired mixing, may be induced and adversely impact the local structure of the simulation. Copyright © 2008 Royal Meteorological Society
Conformational properties of the macrocyclic trichothecene mycotoxin verrucarin A in solution
Authors: Fragaki Georgia , Stefanaki Irine , Dais Photis , Mikros Emmanuel
Published: October 2008

Phase‐sensitive nuclear Overhauser enhancement spectroscopy (NOESY) experiments, 3J couplings and computational molecular modeling (MM2* and MMFF force fields) were employed to examine the conformational properties of verrucarin A in chloroform solutions. The MMFF force field calculations resulted in a family of 12 low‐energy structures along with their populations, the latter being determined by the NMR analysis of molecular flexibility in solution(NAMFIS) deconvolution analysis. The concluded model was capable of reproducing successfully the experimental NOESY cross‐peak volumes and the proton‐coupling constants. Among the 12 conformers, the one which was similar to the structure of verrucarin A in the solid state was the predominant accounting for 75% of the total relative population, although other low‐energy conformations contributed to a lesser degree in order to explain the experimental data. Copyright © 2008 John Wiley & Sons, Ltd.
Structural elucidation of propargylated products of 3‐substituted‐1,2,4‐triazole‐5‐thiols by NMR techniques
Authors: Chaudhary Preeti M. , Chavan Sayalee R. , Kavitha M. , Maybhate Shailaja P. , Deshpande Sunita R. , Likhite Anjali P. , Rajamohanan P. R.
Published: October 2008

Propargylation of 3‐substituted‐1,2,4‐triazole‐5‐thiols, which predominantly exist as their thione tautomers, was carried out with the view to synthesize different heterocycles and study their biological activity. Three different products namely, a mono S‐propargyl and two S,N‐dipropargyl regioisomers, arising from N1/N2 substitution, were isolated and characterized. Unambiguous structural elucidation of the regioisomers of S,N‐dipropargyl derivatives was achieved by means of 13C1H HMBC technique. The proportion of the regioisomers was found to vary with the substituent on the 1,2,4‐triazole thiols. No product corresponding to N4 substitution was isolated from any of the reactions carried out. Copyright © 2008 John Wiley & Sons, Ltd.
Complete 1H and 13C NMR spectral assignment of benzo[d]isothiazole derivatives and of an isoindole isoster
Authors: Incerti Matteo , Acquotti Domenico , Vicini Paola
Published: October 2008

The complete 1H and 13C NMR assignments of the novel compound methyl 2‐amino‐3‐(benzo[d]isothiazol‐3‐yl)propanoate (1), of 3‐amino‐5‐methylbenzo[d]isothiazole (2) and N‐(t‐butyloxycarbonyl)‐2‐aminobenzo[d]isothiazol‐3(2H)‐one (3) and of the desulfurated isostere of 3, N‐(t‐butyloxycarbonyl)‐2‐aminoisoindolin‐1‐one (4), using 1D and 2D NMR techniques, including COSY, INADEQUATE, HSQC, and HMBC experiments are reported. Copyright © 2008 John Wiley & Sons, Ltd.
Real time HR–MAS NMR: application in reaction optimization, mechanism elucidation and kinetic analysis for heterogeneous reagent catalyzed small molecule chemistry
Authors: Roy Abhijeet Deb , Jayalakshmi K. , Dasgupta Somnath , Roy Raja , Mukhopadhyay Balaram
Published: October 2008

A novel application of in situ 1H high‐resolution magic angle spinning (HR–MAS) NMR technique for real‐time monitoring of H2SO4‐silica promoted formation of 2, 2‐disubstituted quinozolin‐4(3H)‐ones is reported. The detailed NMR spectroscopic data led to elucidation of the mechanism, reaction optimization, kinetics and quantitative analysis of the product accurately and efficiently. The translation of the optimized parameters obtained by 1H HR–MAS NMR in the wet laboratory provided similar results. It is proposed that 1H HR‐MAS has a potential utility for optimization of various organic transformations in solid supported catalyzed reactions. Copyright © 2008 John Wiley & Sons, Ltd.
The efficacy of the bioadhesive patches containing licorice extract in the management of recurrent aphthous stomatitis
Authors: Moghadamnia A. A. , Motallebnejad M. , Khanian M.
Published: October 2008

This study evaluated the efficacy of licorice bioadhesive hydrogel patches to control the pain and reduce the healing time of recurrent aphthous ulcer.

This study was carried out in three episodes of ulcers: in the first episode of ulcer, all 15 patients were asked to record their baseline individual pain level by a visual analog scale. In the second and third episodes, comparative and consecutive subjective and objective evaluations of the bioadhesive were done. The effects of the following variables were investigated: (1) VAS pain score for 5 consecutive days, (2) profile of aphthous ulcers on days 3 and 5, (3) time to complete relief of pain and healing of the ulcers, (4) diameter of the lesions and necrotic zone.

A significant reduction in VAS was recorded following application of the licorice patches on days 2, 3, 4 and 5 compared with the no‐treatment group (p < 0.001). Licorice patches caused a significant reduction in the diameter of the inflammatory halo and necrotic center compared with the placebo group (p = 0.03).

According to the results of this study, licorice bioadhesive can be effective in the reduction of pain and of the inflammatory halo and necrotic center of aphthous ulcers. Copyright © 2008 John Wiley & Sons, Ltd.
Impact of initial condition uncertainties on the predictability of heavy rainfall in the Mediterranean: a case study
Authors: Argence Sébastien , Lambert Dominique , Richard Evelyne , Chaboureau Jean‐Pierre , Söhne Nathalie
Published: October 2008

This study explores the predictability of a heavy rainfall event that struck North Africa on 9 and 10 November 2001. This case is a paradigm of Mediterranean extreme events characterized by the presence of a deep upper‐level trough associated with an intense cyclone which developed over the Western Mediterranean basin. Using the French non‐hydrostatic mesoscale model MESO‐NH, numerical experiments starting from various initial atmospheric states were conducted to assess the impact of initial condition uncertainties on the precipitation and cloud cover forecast. To generate a set of perturbed atmospheric states, a simple date‐shifting initialization method was used. Two sets of simulations were run, using lateral boundaries and initial conditions derived from both the French operational global assimilation system Action de Recherche Petite Echelle Grande Echelle (ARPEGE) and the European Centre for Medium‐Range Weather Forecasts (ECMWF) system. Initial perturbations applied to the upper‐level trough propagated and intensified throughout the simulation, leading to some discrepancy in the forecast of the low‐level cyclone. While it was found that the upper‐level trough and the surface cyclone controlled the location of the overall precipitation pattern, the predictability of smaller‐scale features such as localized heavy rainfall was directly related to specific mesoscale structures. The low‐level jet associated with the surface cyclone and the location and the intensity of the surface‐low both impact upon the triggering and the sustainment of the convective cells. In consequence, small‐scale perturbations of these mesoscale features led to large errors in the precipitation forecast, especially in the Algiers area. Copyright © 2008 Royal Meteorological Society
Degradation of the insecticides thiamethoxam and imidacloprid by zero‐valent metals exposed to ultrasonic irradiation in water medium: electrospray ionization mass spectrometry monitoring
Authors: Lopes Renata P. , de Urzedo Ana P. F. M. , Nascentes Clésia C. , Augusti Rodinei
Published: October 2008

The degradation of thiamethoxam (1) and imidacloprid (2), prototype neonicotinoid insecticides bearing a characteristic N‐NO2 moiety in their structures, promoted by a number of zero‐valent metals (Fe, Sn, Zn) upon ultrasonic irradiation in acidic aqueous solution (pH 2) was investigated. It was verified that thiamethoxam (1) and imidacloprid (2) are quickly and almost completely consumed under these experimental conditions (degradation >90% after a reaction time of 30 min) and that ultrasonic irradiation strongly enhances the degradation rate for both insecticides, especially when zinc and tin are employed. Based on the results from electrospray ionization mass (and tandem mass) spectrometry in the positive ion mode, degradation routes for both insecticides, comprising an initial NO2 → NH2 reduction, were proposed. In addition, products from the dehydrochlorination of imidacloprid were also found to be formed under these conditions. Copyright © 2008 John Wiley & Sons, Ltd.
Binding studies of nNOS‐active amphibian peptides and Ca2+ calmodulin, using negative ion electrospray ionisation mass spectrometry
Authors: Pukala Tara L. , Urathamakul Thitima , Watt Stephen J. , Beck Jennifer L. , Jackway Rebecca J. , Bowie John H.
Published: October 2008

Amphibian peptides which inhibit the formation of nitric oxide by neuronal nitric oxide synthase (nNOS) do so by binding to the protein cofactor, Ca2+calmodulin (Ca2+CaM). Complex formation between active peptides and Ca2+CaM has been demonstrated by negative ion electrospray ionisation mass spectrometry using an aqueous ammonium acetate buffer system. In all cases studied, the assemblies are formed with a 1:1:4 calmodulin/peptide/Ca2+ stoichiometry. In contrast, the complex involving the 20‐residue binding domain of the plasma Ca2+ pump C20W (LRRGQILWFRGLNRIQTQIK‐OH) with CaM has been shown by previous two‐dimensional nuclear magnetic resonance (2D NMR) studies to involve complexation of the C‐terminal end of CaM. Under identical conditions to those used for the amphibian peptide study, the ESI complex between C20W and CaM shows specific 1:1:2 stoichiometry. Since complex formation with the studied amphibian peptides requires Ca2+CaM to contain its full complement of four Ca2+ ions, this indicates that the amphibian peptides require both ends of the CaM to effect complex formation. Charge‐state analysis and an H/D exchange experiment (with caerin 1.8) suggest that complexation involves Ca2+CaM undergoing a conformational change to a more compact structure. Copyright © 2008 John Wiley & Sons, Ltd.
Fractional mass filtering as a means to assess circulating metabolites in early human clinical studies
Authors: Tiller Philip R. , Yu Sean , Bateman Kevin P. , Castro‐Perez Jose , Mcintosh Ian S. , Kuo Yushin , Baillie Thomas A.
Published: October 2008

Recent changes in the regulatory environment have led to a need for new methods to assess circulating human drug metabolites in early clinical studies with respect to their potential toxicological impact. The specific goals of such studies are to determine if the metabolites present in human plasma following administration of a drug candidate also are observed in plasma from the animal studies employed for preclinical toxicological evaluation, and to estimate corresponding exposure margins (animal:human) for the major metabolites. Until recently, the accepted best practice for the characterization of circulating drug metabolites utilized liquid chromatography/tandem mass spectrometry (LC/MS/MS)‐based methodologies, in conjunction with authentic chemical standards, for the detection and quantitative analyses of metabolites predicted from both animal studies and experiments with human liver preparations in vitro. While this approach is satisfactory for anticipated biotransformation products, metabolites that were not expected to circulate in human plasma frequently escape detection. Current accurate mass instruments enable the use of the technique of fractional mass filtering to detect both expected and unexpected metabolites in a rapid, less resource‐intensive and more robust manner. Application of this technology to several clinical development programs at Merck Research Laboratories has demonstrated the value of fractional mass filtering in the assessment of circulating drug metabolites in early clinical trials. Copyright © 2008 John Wiley & Sons, Ltd.
Mass spectrometry for the characterization of unsulfated chondroitin oligosaccharides from 2‐mers to 16‐mers. Comparison with hyaluronic acid oligomers
Authors: Volpi Nicola , Zhang Zhenqing , Linhardt Robert J.
Published: October 2008

This study reports for the first time the complete liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) and tandem mass spectrometry (MS/MS) analyses performed in negative ion mode of saturated unsulfated chondroitin oligosaccharides up to 16‐mers and comparison with hyaluronic acid (HA) oligomers differing only in the nature of the hexosamine residue. MS/MS of the chondroitin disaccharide on the singly charged precursor at m/z 396.1 afforded a glycosidic cleavage C1 product ion at m/z 192.9. In the tetrasaccharide, C2 (m/z 396.0) and C3 (m/z 572.0) product anions were generated by glycosidic cleavage. A C5 [M–2H]2− product ion at m/z 475.1 was generated by the glycosidic cleavage of the hexasaccharide, and a C7 ion (m/z 664.6, charge state of −2) was produced from the octasaccharide. The same fragmentation pattern of deprotonated oligomers was observed for the largest oligosaccharides, from 10‐ to 16‐mers. There has been no previous report of MS/MS spectra for unsulfated chondroitin oligomers of these sizes. Unsulfated saturated chondroitin oligosaccharides with x‐mer units and larger than a tetrasaccharide dissociate to almost exclusively form CX–1‐type ions. Saturated HA oligomers also afforded the same fragmentation pattern as deprotonated oligomers by ESI‐MS and MS/MS analyses. Thus, under the experimental conditions used in the current study, we were unable to distinguish between unsulfated chondroitin and HA. Copyright © 2008 John Wiley & Sons, Ltd.
Thermal formation of mixed‐metal inorganic complexes at atmospheric pressure
Authors: Peng Wen‐Ping , Goodwin Mike P. , Chen Hao , Cooks R. Graham , Wilker Jonathan
Published: October 2008

Atmospheric‐pressure thermal desorption ionization (APTDI), a new variant on older ionization methods, is employed to generate gas‐phase ions from inorganic and organometallic compounds. The method is compared to conventional electrospray ionization (ESI) of these compounds and found in most cases examined to yield simpler mass spectra which are useful in the characterization of the pure compounds. Cluster formation, however, is prominent in these spectra and mixtures of V(IV)O(salen), Ni(II)(salen) and Co(II)(salen) show mixed‐metal cluster ions. This makes APTDI a way to prepare gas‐phase ions which contain multiple selected metal atoms and ligands. Such mixed‐metal complexes can be mass‐selected and structurally characterized by tandem mass spectrometry. Strong contrasts are evident in the dissociation behavior of homonuclear and heteronuclear metal clusters, the latter showing accompanying redox processes. The chemical reactivity accompanying collision‐induced dissociation (CID) of some of the mixed‐metal clusters is typified by the protonated species H+[NiVO(salen)], which undergoes a formal oxidation process (hydrogen atom loss) to give the molecular radical cation of Ni(salen). This ionization method may provide a new route to unique inorganic compounds on surfaces through soft landing of appropriate cluster ions. The contrasting behavior of the ESI and APTDI processes is evident in the salens where ESI shows simple Bronsted acid/base chemistry, no mixed‐metal clusters and no redox chemistry. Copyright © 2008 John Wiley & Sons, Ltd.
A computational approach to characterizing bond linkages of glycan isomers using matrix‐assisted laser desorption/ionization tandem time‐of‐flight mass spectrometry
Authors: Sheng Quanhu , Mechref Yehia , Li Yixue , Novotny Milos V. , Tang Haixu
Published: October 2008

Glycans commonly exhibit variations in their branching structures and glycosidic bond linkages, in addition to their sequence variation. These glycan features are known to be highly correlated with their biological functions. It is relatively straightforward to deduce the composition and sequence of monosaccharides of a glycan from its tandem mass spectra. However, the characterization of the linkage types of each glycosidic bond is still analytically challenging. In this paper, we present a rank‐based discriminative model to differentiate between two types of glycosidic linkages (namely, 1‐4 and 1‐6) based on the cross‐ring fragmentation patterns of the corresponding glycans observed under high‐energy collision‐induced dissociation (CID). To train our models, we acquired tandem mass spectra for three groups of both native and permethylated linear oligoglucoses using a matrix‐assisted laser desorption/ionization tandem time‐of‐flight (MALDI/TOF/TOF) instrument. Based on a 5‐fold cross‐validation, the prediction accuracies of our model for native glycans are determined to be about 88.4% and 92.9% for 1‐6 and 1‐4 linkages, respectively. The accuracies determined for permethylated glycans are slightly lower, but comparable: 85.6% and 89.0% for 1‐6 and 1‐4 linkages, respectively. Our method is implemented as a web‐hosted utility, thus making it readily accessible to the public which can be accessed through http://ggdb.informatics.indiana.edu:8080/glycanview. Copyright © 2008 John Wiley & Sons, Ltd.
A non‐covalent dimer formed in electrospray ionisation mass spectrometry behaving as a precursor for fragmentations
Authors: Pan Hefeng
Published: October 2008

A non‐covalent‐bonded dimer was detected in the positive ion electrospray ionisation (ESI) mass spectra of a synthetic impurity. In tandem mass spectrometry (MS/MS) experiments using collision‐induced dissociation (CID), the ion was found to behave as a [M+H]+‐type precursor ion for fragmentation until MS5. The dimer was probably formed through multi‐hydrogen bonds over a proton bridge. When the fragmentation occurred at the center of the bridge, the dimer was broken apart to give monomer fragments at MS6. However, no corresponding deprotonated dimer [2M–H]− was found in the negative ion ESI spectra. The dimer was extremely stable, and it could still be observed when a fragmentation voltage of up to 50 V was applied in the ionisation source. The formation of the non‐covalent dimer was also found to be instrument‐dependent, but independent of sample concentration. Accurate mass measurements of the [2M+H]+ and [M+H]+ ions, and their MSn product ions, provided the basis for assessing the fragmentation mechanism proposed for [2M+H]+. The fragmentation pathway was also illustrated for the deprotonated molecule [M–H]−. Copyright © 2008 John Wiley & Sons, Ltd.