bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying the Relative Importance of Leaf versus Shredder Species Loss on Litter Decomposition in Streams
Authors: Swan Christopher M. , Brown Bryan L. , DePalma Carrie A. 
Published: August 2009

AbstractUnderstanding how species loss influences ecosystem function is a contemporary issue in ecology. However, most research has focused on species loss at one trophic‐level. We explored the relationship between functional diversity (FD) and species richness separately for trees and aquatic leaf‐shredding detritivores. For trees, we collected information on species‐specific leaf tissue chemistry and species co‐occurrences in the mid‐Atlantic region (USA). For shredders, we used a published trait database with information on communities from 38 streams in the same region. We used a clustering algorithm to estimate FD for each community and for randomly assembled communities. If FD was high, we concluded that species loss was important to change in function; if low, species were functionally redundant and insensitive to species loss. We found tree FD to be significantly different than expected, but shredders exhibited FD levels similar to patterns based on random assembly. Furthermore, there were more leaf species exclusively associated with very high or very low levels of functional diversity compared to shredders. This approach revealed greater implications for leaf than shredder species loss for litter breakdown. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nutrient Uptake and Mineralization during Leaf Decay in Streams – a Model Simulation
Authors: Webster J. R. , Newbold J. D. , Thomas S. A. , Valett H. M. , Mulholland P. J. 
Published: August 2009

AbstractWe developed a stoichiometrically explicit computer model to examine how heterotrophic uptake of nutrients and microbial mineralization occurring during the decay of leaves in streams may be important in modifying nutrient concentrations. The simulations showed that microbial uptake can substantially decrease stream nutrient concentrations during the initial phases of decomposition, while mineralization may produce increases in concentrations during later stages of decomposition. The simulations also showed that initial nutrient content of the leaves can affect the stream nutrient concentration dynamics and determine whether nitrogen or phosphorus is the limiting nutrient. Finally, the simulations suggest a net retention (uptake > mineralization) of nutrients in headwater streams, which is balanced by export of particulate organic nutrients to downstream reaches. Published studies support the conclusion that uptake can substantially change stream nutrient concentrations. On the other hand, there is little published evidence that mineralization also affects nutrient concentrations. Also, there is little information on direct microbial utilization of nutrients contained in the decaying leaves themselves. Our results suggest several directions for research that will improve our understanding of the complex relationship between leaf decay and nutrient dynamics in streams. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leaf‐Litter Mixtures Affect Breakdown and Macroinvertebrate Colonization Rates in a Stream Ecosystem
Authors: Abelho Manuela 
Published: August 2009

AbstractPrevious work in terrestrial and aquatic ecosystems has suggested that the relationship between breakdown rates of leaf litter and plant species richness may change unpredictability due to non‐additive effects mediated by the presence of key‐species. By using single‐ and mixed‐species leaf bags (7 possible combinations of three litter species differing in toughness; common alder [Alnus glutinosa ], sweet chestnut [Castanea sativa ], and Spanish oak [Quercus ilex ilex ]), I tested whether leaf species diversity, measured as richness and composition, affects breakdown dynamics and macroinvertebrate colonization (abundance, richness and composition) during 90 days incubation in a stream. Decomposition rates were additive, i.e., observed decomposition rates were not different from expected ones. However, decomposition rates of individual leaf species were affected by the mixture, i.e., there were species‐specific responses to mixing litter. The invertebrate communities colonizing the mixtures were not richer and more diverse in mixtures than in single‐species leaf bags. On the opposite, mixing leaf species had a negative, non‐additive effect on rates of shredder and taxa colonization and on macroinvertebrate diversity. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leaf Litter Dynamics and Its Use by Invertebrates in a High‐Altitude Tropical Andean Stream
Authors: Touma Blanca Rios , Encalada Andrea C. , Fornells Narcís Prat 
Published: August 2009

AbstractThis study evaluates litter dynamics and its relation to macroinvertebrate communities (assemblages and feeding habits) at Piburja stream (3300 m, Ecuador). Annual litterfall (216 g AFDM/m2) was not related to rainfall, but differed significantly between months. Transport of Coarse Particulate Organic Matter (CPOM) did not differ between seasons, but retention was higher during the dry season. Thus, CPOM standing stock was higher in the dry (125.28 g AFDM/m2) compared to the wet season (12.27 g AFDM/m2). Macroinvertebrate richness and diversity were positively related to Coarse Benthic Organic Matter (CBOM) especially during the wet season. Gut content analysis revealed that, regardless of season, CPOM and Fine Particulate Organic Matter (FPOM) were the most important food items in the diet of most invertebrate taxa, including those that are not considered shredders or gathering collectors in the literature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Responses of Aquatic Fungal Communities on Leaf Litter to Temperature‐Change Events
Authors: Fernandes Isabel , Uzun Begüm , Pascoal Cláudia , Cássio Fernanda 
Published: August 2009

AbstractIncreases of extreme weather events are predicted to occur with ongoing climate change, but impacts to freshwaters have rarely been examined. We assessed the effects of temperature on leaf‐litter associated fungi by exposing leaves colonized in a stream to 18 °C (control), 25 °C, or 18 °C after freezing. Treatments altered fungal dominance on leaves; Lunulospora curvula sporulation was stimulated by increased temperature and stopped by the freeze‐thaw treatment. Fungal biomass and diversity decreased at 18 °C after freezing, but not at 25 °C. Leaf decomposition was retarded by the freeze‐thaw treatment (k = –0.024 day–1) and stimulated at 25 °C (k = –0.069 day–1). Results suggest that occasional freezing may constrain fungal diversity and their ecological functions, while warming appears to accelerate plant‐litter decomposition in streams. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Potential Contribution of Microfungi to the Decomposition of Reed Leaf Detritus in a Coastal Lagoon: A Laboratory and Field Experiment
Authors: Mancinelli Giorgio , Vignes Fabio , Sangiorgio Franca , Mastrolia Annunziata , Basset Alberto 
Published: August 2009

AbstractThe potential contribution of microfungi to reed decomposition in a coastal habitat (Le Cesine Lagoon, Italy) was investigated under laboratory and field conditions. Leaf pack mass and surface loss, ergosterol content and O2 uptake were used to construct carbon budgets and an empirical ergosterol‐to‐O2 uptake relationship based on literature data was used to estimate the contribution of microfungi. Under laboratory conditions, reed carbon loss was entirely due to leaching and microbial respiration. In contrast, C losses observed in the field were accounted for by microbial respiration and macroinvertebrate shredding almost equally. Microfungi were estimated to account for 98% and 69% of microbially‐respired carbon under laboratory and field conditions, respectively. Our results provide a preliminary, quantitative assessment of microfungal contribution to reed decomposition in brackish habitats. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure‐kinetic relationship analysis of the therapeutic complement inhibitor compstatin
Authors: Magotti Paola , Ricklin Daniel , Qu Hongchang , Wu You‐Qiang , Kaznessis Yiannis N. , Lambris John D. 
Published: August 2009

AbstractCompstatin is a 13‐residue peptide that inhibits activation of the complement system by binding to the central component C3 and its fragments C3b and C3c. A combination of theoretical and experimental approaches has previously allowed us to develop analogs of the original compstatin peptide with up to 264‐fold higher activity; one of these analogs is now in clinical trials for the treatment of age‐related macular degeneration (AMD). Here we used functional assays, surface plasmon resonance (SPR), and isothermal titration calorimetry (ITC) to assess the effect of modifications at three key residues (Trp‐4, Asp‐6, Ala‐9) on the affinity and activity of compstatin and its analogs, and we correlated our findings to the recently reported co‐crystal structure of compstatin and C3c. The KD values for the panel of tested analogs ranged from 10−6 to 10−8 M. These differences in binding affinity could be attributed mainly to differences in dissociation rather than association rates, with a >4‐fold range in kon values (2–10 × 105 M−1 s−1) and a koff variation of >35‐fold (1–37 × 10−2 s−1) being observed. The stability of the C3b‐compstatin complex seemed to be highly dependent on hydrophobic effects at position 4, and even small changes at position 6 resulted in a loss of complex formation. Induction of a β‐turn shift by an A9P modification resulted in a more favorable entropy but a loss of binding specificity and stability. The results obtained by the three methods utilized here were highly correlated with regard to the activity/affinity of the analogs. Thus, our analyses have identified essential structural features of compstatin and provided important information to support the development of analogs with improved efficacy. Copyright © 2009 John Wiley & Sons, Ltd.
Surface application of calcium‐containing gels to improve quality of late maturing peach cultivars
Authors: Fernández Victoria , Díaz Azahara , Blanco Álvaro , Val Jesús 
Published: August 2009

AbstractBACKGROUND: A strategy to supply Ca directly to fruits as a tool for improving peach quality has been devised and tested under field conditions. Since peaches in the area of study (Calanda, Spain) are routinely bagged shortly after thinning, a method based on the application of Ca gels to the fruit surface was introduced. The effect of surface treatments was assessed in terms of quality, nutrient balance and surface deposition.RESULTS: Application of Ca‐containing formulations increased mesocarp and exocarp Ca concentrations, providing evidence for the penetration of Ca through the peach skin. Surface Ca treatments had a particular mode of deposition and in some instances improved the shelf life of fruits without affecting their quality.CONCLUSION: Surface treatment with Ca‐containing gels appears to be a viable approach to increase fruit Ca, quality and storability of bagged peach cultivars and should be optimised in future studies. Copyright © 2009 Society of Chemical Industry
Differentiation and dating of red ink entries of seals on documents by HPLC and GC/MS
Authors: Yao Ya‐Tong , Song Jia , Yu Jing , Wang Xiang‐Feng , Hou Feier , Zhang Ai‐Lan , Liu Yuan , Han Jie , Xie Meng‐Xia 
Published: August 2009

AbstractA novel approach for differentiation and dating of red ink entries of seals on documents was developed based on ion‐pairing HPLC (IP‐HPLC) and GC/MS. Sixty‐nine red ink pastes of seals were collected and the chromatographic conditions for separation of the dye components by IP‐HPLC and the volatile additives by GC/MS in the ink entries were optimized. According to the dye components and additives, the ink entries were classified by HPLC with a multi‐wavelength UV detector. The volatile components of the inks were identified by GC/MS and the classification of the ink entries was also investigated based on these volatile additives. The results showed that most of the ink entries of the seals can be differentiated by combining HPLC with a multi‐wavelength detector and GC/MS methods. The degradation of the standard dye mixtures and the compositional changes of the ink entries of seals were investigated in light or natural aging conditions. The results indicated that the dye components decomposed in light or natural storage conditions, while the rates of the degradation depended on the structures of the dye components, the aging conditions, even the additives of the ink pastes. The results also showed that there existed good relationships between the compositional changes of the ink entries and the aging time, which can provide scientific evidences and valuable clues for dating of the ink entries.
Ultrasound assisted ionic liquid dispersive liquid phase extraction of lovastatin and simvastatin: A new pretreatment procedure
Authors: Mao Tao , Hao Bo , He Jin , Li Weilin , Li Shengqing , Yu Ziniu 
Published: August 2009

AbstractA fast and novel sample preparation procedure: ultrasound assisted ionic liquid (IL) dispersive liquid extraction for the concentration of lovastatin and simvastatin in aqueous samples was developed. An IL ([C6MIM][PF6]) was used as the extraction solvent, and the factors affecting the extraction efficiency such as initial temperature, the volume of IL, pH of water samples, cooling time, and salt concentration were optimized. In combination with HPLC‐UV, both lovastatin and simvastatin exhibited a good linear range of 1–100 ng/mL. The limits of detection (LODs) of lovastatin and simvastatin were 0.17 and 0.29 ng/mL, respectively. Precisions of the proposed method (RSDs, n = 9) were 4.12 and 4.52%, respectively. This method has been successfully applied for the analysis of target compounds in three real water samples and good spiking recoveries were obtained in the range of 90.0–102.2% for lovastatin and 80.5–112.0% for simvastatin. These results indicated that ultrasound assisted IL dispersive liquid phase extraction would have good application prospect in the pretreatment of environmental samples.
Managing the wildlife tourism experience: The importance of tour leaders
Authors: Curtin Susanna 
Published: August 2009

AbstractThis paper is based on a small ethnographic study of serious wildlife tourists. It focuses on three important aspects of this type of travel. First, the tangible benefits of the tourist experience; second, the importance of the tour leader as the interface between the product and the tourist; and finally, tourist perceptions of their potential environmental and social impacts. The findings reveal participants' environmental sensibilities and the desire to avoid disturbance, the social benefits of organised tours and how the tour leader is critical to both the success of the holiday and the responsible behaviour of the group. Copyright © 2009 John Wiley & Sons, Ltd.
The geomorphic impact of afforestations on soil erosion in Southeast Spain
Authors: Romero‐Diaz A. , Belmonte‐Serrato F. , Ruiz‐Sinoga J. D. 
Published: August 2009

AbstractSemiarid lands have been affected by intense afforestations since the end of the 20th century. Plantations were developed to control soil and water losses, prevent flooding, reduce check dams silting and, since the 1970s, to fight against desertification. The afforestations in semiarid environments were and are developed by means of aggressive techniques, employing heavy machinery and landform changes. In the Region of Murcia, South eastern Spain, studies have been carried out for the last three decades in afforested areas mainly on marls, conglomerates and schists. Sub‐soiling has been used in order to transform the straight slopes into a terraced man‐made landscape. Geomorphological transects, topographic profiles and erosion plots have been used to quantify the erosion rates on afforested and non‐afforested areas. The results show an increase in water erosion as a consequence of afforestation. Soil erosion rates were 105 Mg ha−1 y−1in marls, 63 Mg ha−1 y−1in conglomerates and 29 Mg ha−1 y−1in schists, where rills and gullies were widespread. Soil erosion rates were lower than 2 Mg ha−1 y−1on the control plots (in all parent materials) due to the scrubland cover. Afforestations contributed in increasing soil losses between 1 and 2 orders of magnitude. However, the regional, national and European governments are planning to invest in new afforestation programmes. Copyright © 2009 John Wiley & Sons, Ltd.
Photochemical Generation of Ferrocene‐Based Redox‐Polymer Networks
Authors: Bunte Christine , Rühe Jürgen 
Published: August 2009

AbstractA photochemical approach toward the generation of enzyme‐containing redox polymer networks, which are the key material in enzymatic sensors and biofuel cells, is described. The approach is based on the incorporation of photo‐reactive benzophenone groups into the redox polymers. The obtained polymers are then deposited on the surface of glassy carbon electrodes and cross‐linked by illumination with UV light at 365 nm. If this step is done in the presence of the enzyme glucose oxidase, functional electrodes are obtained that yield electrical power upon addition of glucose. This work specifically addresses the question of electrode stability in buffer and demonstrates how slight variations in the chemistry of the redox polymer have a dramatic effect on the electrochemical performance of the electrodes. Different ferrocene‐containing redox polymer networks are synthesized and their properties in physiological buffer are studied.magnified image
EGCG inhibits protein synthesis, lipogenesis, and cell cycle progression through activation of AMPK in p53 positive and negative human hepatoma cells
Authors: Huang Chi‐Hung , Tsai Shang‐Jie , Wang Ying‐Jan , Pan Min‐Hsiung , Kao Jung‐Yie , Way Tzong‐Der 
Published: August 2009

AbstractIn the previous studies, (–)‐epigallocatechin‐3‐gallate (EGCG) has been shown to have anticarcinogenic effects via modulation in protein expression of p53. Using p53 positive Hep G2 and p53 negative Hep 3B cells, we found that treatment of EGCG resulted in dose‐dependent inhibition of cellular proliferation, which suggests that the interaction of EGCG with p53 may not fully explain its inhibitory effect on proliferation. Caloric restriction (CR) reduces the incidence and progression of spontaneous and induced tumors in laboratory rodents. EGCG has multiple beneficial activities similar to those associated with CR. One key enzyme thought to be activated during CR is AMP‐activated kinase (AMPK), a sensor of cellular energy levels. Here, we showed that EGCG activated AMPK in both p53 positive and negative human hepatoma cells. The activation of AMPK suppressed downstream substrates, such as mammalian target of rapamycin (mTOR) and eukaryotic initiation factor 4E‐binding protein‐1 (4E‐BP1) and a general decrease in mRNA translation. Moreover, EGCG activated AMPK decreases the activity and/or expression of lipogenic enzymes, such as fatty acid synthase (FASN) and acetyl‐CoA carboxylase (ACC). Interestingly, the decision between apoptosis and growth arrest following AMPK activation is greatly influenced by p53 status. In p53 positive Hep G2 cells, EGCG blocked the progression of cell cycle at G1 phase by inducing p53 expression and further up‐regulating p21 expression. However, EGCG inducted apoptosis in p53 negative Hep 3B cells. Based on these results, we have demonstrated that EGCG has a potential to be a chemoprevention and anti‐lipogenesis agent for human hepatoma cells.
Ankle torque steadiness is related to muscle activation variability and coactivation in children with cerebral palsy
Authors: Bandholm Thomas , Rose Martin H. , SlØk Rikke , Sonne‐Holm Stig , Jensen Bente R. 
Published: August 2009

AbstractThe aims of this study were to: (1) investigate the significance of muscle activation variability and coactivation for the ability to perform steady submaximal ankle torque (torque steadiness) in healthy children and those with cerebral palsy (CP), and (2) assess ankle function during isometric contractions in those children. Fourteen children with CP who walked with equinus foot deformity and 14 healthy (control) children performed maximal and steady submaximal ankle dorsi‐ and plantarflexions. Dorsiflexion torque steadiness was related to agonist and antagonist muscle activation variability as well as the plantarflexor coactivation level in children with CP (r > 0.624, P < 0.03). Moreover, children with CP displayed reduced maximal torque and submaximal torque steadiness of both dorsi‐ and plantarflexion compared with controls (P < 0.05). Both muscle groups may benefit from strength training, as they exhibit poor submaximal control and weakness in children with CP. Muscle Nerve, 2009
Spatially resolved quantification of agrochemicals on plant surfaces using energy dispersive X‐ray microanalysis
Authors: Hunsche Mauricio , Noga Georg 
Published: August 2009

AbstractBACKGROUND: In the present study the principle of energy dispersive X‐ray microanalysis (EDX), i.e. the detection of elements based on their characteristic X‐rays, was used to localise and quantify organic and inorganic pesticides on enzymatically isolated fruit cuticles. Pesticides could be discriminated from the plant surface because of their distinctive elemental composition.RESULTS: Findings confirm the close relation between net intensity (NI) and area covered by the active ingredient (AI area). Using wide and narrow concentration ranges of glyphosate and glufosinate, respectively, results showed that quantification of AI requires the selection of appropriate regression equations while considering NI, peak‐to‐background (P/B) ratio, and AI area. The use of selected internal standards (ISs) such as Ca(NO3)2 improved the accuracy of the quantification slightly but led to the formation of particular, non‐typical microstructured deposits. The suitability of SEM‐EDX as a general technique to quantify pesticides was evaluated additionally on 14 agrochemicals applied at diluted or regular concentration.CONCLUSION: Among the pesticides tested, spatial localisation and quantification of AI amount could be done for inorganic copper and sulfur as well for the organic agrochemicals glyphosate, glufosinate, bromoxynil and mancozeb. Copyright © 2009 Society of Chemical Industry
Conversion of Methyl Oleate to Branched‐Chain Hydroxy Fatty Acid Derivatives
Authors: Dailey Oliver D. , Prevost Nicolette T. , Strahan Gary D. 
Published: August 2009

AbstractAs part of a project to develop new and expanded uses of oilseed products and by‐products (such as biodiesel, fuel additives, and lubricants), studies were conducted on the synthetic conversion of oleic acid (in the ester form) to branched‐chain fatty acid ester derivatives. In these studies, methyl oleate was epoxidized and subsequently treated with four different organocuprate reagents in the presence of boron trifluoride diethyl etherate to produce novel branched‐chain hydroxy acid derivatives. For each reaction, the two distinct isomeric products (methyl 9‐alkyl‐10‐hydroxyoctadecanoate and methyl 9‐hydroxy‐10‐alkyloctadecanoate) were isolated in the pure forms. Details of the synthesis and characterization (GC–MS, NMR, and differential scanning calorimetry) of these compounds will be discussed.