bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity and nicotinic acetylcholine receptor interaction of imidacloprid and its metabolites in Apis mellifera (Hymenoptera: Apidae)
Authors: Nauen Ralf , Ebbinghaus‐Kintscher Ulrich , Schmuck Richard 
Published: January 2005

AbstractAcute oral and contact toxicity tests of imidacloprid, an insecticide acting agonistically on nicotinic acetylcholine receptors (nAChR), to adult honeybees, Apis mellifera L var carnica, were carried out by seven different European research facilities. Results indicated that the 48‐h oral LD50 of imidacloprid is between 41 and >81 ng per bee, and the contact LD50 between 49 and 102 ng per bee. The ingested amount of imidacloprid‐containing sucrose solution decreased with increasing imidacloprid concentrations and may be attributed to dose‐related sub‐lethal intoxication symptoms or to antifeedant responses. Some previously reported imidacloprid metabolites occuring at low levels in planta after seed dressing, ie olefine‐, 5‐OH‐ and 4,5‐OH‐imidacloprid, showed lower oral LD50 values (>36, >49 and 159 ng per bee, respectively) compared with the concurrently tested parent molecule (41 ng per bee). The urea metabolite and 6‐chloronicotinic acid (6‐CNA) exhibited LD50 values of >99 500 and >121 500 ng per bee, respectively.The pharmacological profile of the [3H]imidacloprid binding site in honeybee head membrane preparations is consistent with that anticipated for a nAChR. IC50 values for the displacement of [3H]imidacloprid by several metabolites such as olefine, 5‐OH‐, 4,5‐OH‐imidacloprid, urea and 6‐CNA were 0.45, 24, 6600, >100 000, and >100 000 nM, respectively. Displacement of [3H]imidacloprid by imidacloprid revealed an IC50 value of 2.9 nM, thus correlating well with the observed acute oral toxicity of the compounds in honeybees.Neurons isolated from the antennal lobe of A mellifera and subjected to whole‐cell voltage clamp electrophysiology responded to the application of 100 µM acetylcholine with a fast inward current of between 30 and 1600 pA at −70 mV clamp potential. Imidacloprid and two of the metabolites (olefine‐ and 5‐OH‐imidacloprid) acted agonistically on these neurons, whereas the others did not induce currents at test conencentrations up to 3 mM. The electrophysiological data revealed Hill coefficients of approximately 1, indicating a single binding site responsible for an activation of the receptor and no direct cooperativity or allosteric interaction with a second binding site.© 2001 Society of Chemical Industry
Evaluation of endosulfan residues in vegetables grown in greenhouses
Authors: Arrebola Francisco J , Egea‐González Francisco J , Moreno Mercedes , Fernández‐Gutiérrez Alberto , Hernández‐Torres Maria E , Martínez‐Vidal José L 
Published: January 2005

AbstractThe reduction in residue levels of endosulfan with time after treatment of tomatoes, green beans, peppers and cucumbers grown in different types of commercial greenhouses (flat‐ and asymmetric‐roof greenhouses) in Almería (Spain) was investigated. A study of the major and minor degradation products of endosulfan in peppers and cucumbers (endosulfan‐sulfate, ‐ether and ‐lactone) was carried out using gas chromatography–tandem mass spectrometry (GC–MS/MS). To establish the influence of environmental conditions on the degradation of endosulfan, several field trials have been carried out in which crops were sprayed at different rates (full, half‐ and quarter‐ of those rates recommended) during two seasons (spring and winter). For statistical purposes, the disappearance of endosulfan with time was considered to follow a pseudo‐first‐order reaction. Analysis of variance (ANOVA) has been applied to the results obtained. Half‐lives of residue disappearance were 4.03–4.68 days in green beans, 4.03–4.20 days in tomatoes, 8.22 days in peppers and 7.97 days in cucumbers. Half‐lives in spring were shorter than in the winter season. The application rate and the type of greenhouse did not influence the half‐lives.© 2001 Society of Chemical Industry
Toxicity of synthetic piperonyl compounds to leaf‐cutting ants and their symbiotic fungus
Authors: Victor Sandra R , Crisóstomo Fernando R , Bueno Fabiana C , Pagnocca Fernando C , Fernandes João B , Correa Arlene G , Bueno Odair C , Hebling M José A , Bacci Maurício , Vieira Paulo C , da Silva M Fátima G F 
Published: January 2005

AbstractThe development of Leucoagaricus gongylophorus, the fungus cultured by the leaf‐cutting ant Atta sexdens was inhibited in vitro by synthetic compounds containing the piperonyl group. In addition, worker ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls. The inhibition of the fungal growth increased with the size of the carbon side chain ranging from C1 through C8 and decreasing thereafter. 1‐(3,4‐Methylenedioxybenzyloxy)octane (compound 5) was the most active compound and inhibited the fungal development by 80% at a concentration of 15 µg ml−1. With worker ants the toxic effects started with compound 5 and increased with the number of carbons in the side chain. Thus, for the same concentration (100 µg ml−1) the mortality rates observed after 8 days of diet ingestion were 82%, 66% and 42%, for 1‐(3,4‐methylenedioxybenzyloxy)decane, 1‐(3,4‐methylenedioxybenzyloxy)dodecane and compound 5, respectively, whereas with commercial piperonyl butoxide the mortality was 68%. The latter compound, which is known as a synergist insecticide, was as inhibitory to the symbiotic fungus as the synthetic compound 5. The possibility of controlling these insects in the future using compounds that can target simultaneously both organisms is discussed.© 2001 Society of Chemical Industry
Dicofol resistance in Tetranychus cinnabarinus: resistance and stability of resistance in populations from Antalya, Turkey
Authors: Dağlı Fatih , Tunç Írfan 
Published: January 2005

AbstractResistance against dicofol was investigated in the carmine spider mite, Tetranychus cinnabarinus. Higher resistance levels were detected by leaf residual bioassays than by topical bioassays, both done using a Potter spray tower, in almost all populations of T cinnabarinus examined from Antalya, Turkey. For instance, the resistance level at LC95 was 17.5‐fold in topical bioassays but 58.9‐fold in leaf residual bioassays for the population collected from greenhouses in the Topçular district. There were differences of resistance levels at LC95, ranging between 2.6‐ and 23.9‐fold using topical bioassays and between 5.0‐ and 58.9‐fold in residual bioassays, in populations collected from greenhouses from various districts. Populations from cotton showed lower resistance levels against dicofol than populations from greenhouses.Resistance to dicofol at LC50 as indicated by topical and residual bioassays increased 19.7‐ and 100.7‐fold, respectively, in a colony from the laboratory strain of T cinnabarinus selected with dicofol alone for 16 cycles. However, the dicofol resistance at LC50 increased 19.4‐ and 52.0‐fold in another colony selected in rotation with dicofol and tetradifon for six and eight cycles, respectively. The changes in resistance to dicofol 5 months after the selection ceased were as follows: in the colony selected for dicofol alone, using topical and residual bioassays, the resistance levels at LC50 decreased to 11.7‐ and 99.1‐fold, respectively, and in the colony selected in rotation with dicofol and tetradifon to 10.8‐ and 15.8‐fold, respectively.© 2001 Society of Chemical Industry
The concentration of pesticides in sediments from Kolleru Lake in India
Authors: Sreenivasa Rao Amaraneni , Pillala Ramamohana R 
Published: January 2005

AbstractKolleru Lake is the largest natural freshwater lake in India. Sediment samples were collected at different locations from Kolleru Lake at different seasons in a year over a period of three years and analyzed for eight selected pesticides. In general, pesticides were present at all locations. The selected pesticides α‐BHC, γ‐BHC, malathion, chlorpyrifos and endosulfan were present at higher concentrations than isodrin, dieldrin and p,p′‐DDT.The concentrations of α‐BHC, γ‐BHC malathion, chlorpyrifos, isodrin, endosulfan, dieldrin and p,p′‐DDT in sediments were 1.2–388, 1.4–212, from below the minimum detection limit (BDL)–186, 1.1–292, BDL–38.6, BDL–206, BDL–128 and BDL–191 µg kg−1 dry weight, respectively. The aim of this study is to evaluate baseline data, to try to account for the concentration of pesticides in sediments and to discuss their potential to affect human beings and aquatic organisms.© 2001 Society of Chemical Industry
Synthesis and in vitro antifungal activity of 1‐amino‐3,4‐dialkylnaphthalene‐2‐carbonitriles and their analogues
Authors: Wilamowski Jarosław , Kulig Ewa , Sepioł Janusz J , Burgieł Zbigniew J 
Published: January 2005

AbstractTwenty‐four 3‐ and/or 4‐alkyl‐substituted 1‐aminonaphthalene‐2‐carbonitriles and their analogues were prepared and evaluated for growth‐inhibiting activity against four phytopathogenic fungi: Fusarium culmorum, Alternaria brassicicola, Botrytis cinerea and Penicillium expansum. The results obtained were compared with the activity of a commercial fungicide. The highest fungistatic activity was revealed by amino nitriles having hydrogen atoms or only one short alkyl group (CH3, C2H5) at the 3‐ or 4‐position of the naphthalene system. The minimum values of calculated EC50 and EC95 indexes were 1.1 and 5.1 mg litre−1, respectively. These values were considerably lower than those for the reference fungicide.© 2001 Society of Chemical Industry
Adsorption–desorption behaviour of flufenacet in five different soils of India
Authors: Gajbhiye Vijay T , Gupta Suman 
Published: January 2005

AbstractAdsorption–desorption of the herbicide flufenacet (FOE 5043) has been studied in five soils from different locations in India (Delhi, Ranchi, Nagpur, Kerala and Assam) varying in their physico‐chemical properties. The organic matter (OM) content varied from 0.072 to 0.864%, clay content from 2.5 to 43.7% and pH from 4.45 to 8.35. The adsorption studies were carried out using a batch equilibration technique. Ten grams of soil were equilibrated with 20 ml of aqueous 0.01 M CaCl2 solution containing different concentrations (0–30 mg litre−1) of flufenacet. After equilibration, an aliquot of supernatant was taken out for analysis. During desorption, the amount withdrawn for analysis was replenished with fresh 0.01 M CaCl2 solution and further equilibrated. Desorption studies were carried out with the 30 mg litre−1 concentration of flufenacet only. The adsorption studies revealed that there was moderate to high adsorption of flufenacet considering the comparatively low organic carbon content in the five test soils. Average Kd values ranged from 0.77 to 4.52 and Freundlich KF values from 0.76 to 4.39. The highest adsorption was observed in Kerala soil (OM 0.786%; clay 25%; pH 4.45) followed by Ranchi, Nagpur and Delhi soils, and the lowest in Assam soil (OM 0.553%; clay 2.5%; pH 6.87). The trend in adsorption could be attributed to the chemical nature of flufenacet and the physico‐chemical properties of the soil such as pH, OM and clay contents. OM and clay contents were positively correlated whereas pH was negatively correlated. Soils having low pH, high OM and high clay contents showed higher adsorption. Desorption studies revealed that there was a hysteresis effect in all the soils. Hysteresis coefficient values (ratio of nad and ndes) varied from 0.09 to 0.45. The study implies that, because of its moderate to high adsorption, flufenacet is likely to persist in soil for some time. However, the possibility of its movement by leaching or surface run off is less.© 2001 Society of Chemical Industry
A personal account of the role of peptide research in drug discovery: the case of hepatitis C1
Authors: Pessi Antonello 
Published: January 2005

AbstractAlthough peptides themselves are not usually the end products of a drug discovery effort, peptide research often plays a key role in many aspects of this process. This will be illustrated by reviewing the experience of peptide research carried out at IRBM in the course of our study of hepatitis C virus (HCV). The target of our work is the NS3/4A protease, which is essential for maturation of the viral polyprotein. After a thorough examination of its substrate specificity we fine‐tuned several substrate‐derived peptides for enzymology studies, high‐throughput screening and as fluorescent probes for secondary binding assays. In the course of these studies we made the key observation: that the protease is inhibited by its own cleavage products. Single analog and combinatorial optimization then derived potent peptide inhibitors. The crucial role of the NS4A cofactor was also addressed. NS4A is a small transmembrane protein, whose central domain is the minimal region sufficient for enzyme activation. Structural studies were performed with a peptide corresponding to the minimal activation domain, with a series of product inhibitors and with both. We found that NS3/4A is an induced fit enzyme, requiring both the cofactor and the substrate to acquire its bioactive conformation; this explained some puzzling results of ‘serine‐trap’ type inhibitors. A more complete study on NS3 activation, however, requires the availability of the full‐length NS4A protein. This was prepared by native chemical ligation, after sequence engineering to enhance its solubility; structural studies are in progress. Current work is focused on the P′ region of the substrate, which, at variance with the P region, is not used for ground state binding to the enzyme and might give rise to inhibitors showing novel interactions with the enzyme.

Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
New conformationally homogeneous β‐turn antagonists of the human B2 kinin receptor
Authors: Monteagudo Edith S. , Calvani Federico , Catrambone Fernando , Fincham Christopher I. , Madami Andrea , Meini Stefania , Terracciano Rosa 
Published: January 2005

AbstractWe have designed and synthesized a conformationally homogeneous series of cyclic pentapeptides of the general structure c[Pro‐aai‐𝒹‐Tic‐Oic‐aai+3] which adopt a type‐II′ β‐turn conformation believed important for high affinity antagonism of the bradykinin (BK) B2 receptor. We incorporated 𝒹‐Tic and octahydroindole‐2‐carboxylic acid (Oic) residues (present in known active antagonists) in a cyclic pentapeptide that would place the 𝒹‐aa in the i+l position of the β‐turn and a proline as a bridge between the C‐ and N‐termini sides of the turn. In positions i and i+3 alkyl, aromatic, polar or charged amino acids could be introduced without dramatically changing the overall structure. Ten analogues were studied using 1H nuclear magnetic resonance (NMR) and evaluated for their binding affinity for the human B2 receptor. The NMR data in dimethylsulfoxide (DMSO) confirmed the structural homogeneity within the class and, on the basis of this, one representative member of the series was chosen for a detailed structure determination using NMR data in sodium dodecylsulphate (SDS) micelles and molecular dynamics calculations. Despite the structural similarity, the binding affinity of the ten analogues was strongly influenced by the nature of the side‐chains in positions i and i+3, with the doubly charged analogue 49 (pKi=6.2) proving best. This compound may serve as the starting point for the discovery of new non‐peptide bradykinin B2 receptor antagonists. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
The amyloid‐β peptide and its role in Alzheimer's disease
Authors: Clippingdale Andrew B. , Wade John D. , Barrow Colin J. 
Published: January 2005

AbstractAmyloid formation plays a central role in the cause and progression of Alzheimer's disease. The major component of this amyloid is the amyloid‐β (Aβ) peptide, which is currently the subject of intense study. This review discusses some recent studies in the area of Aβ synthesis, purification and structural analysis. Also discussed are proposed mechanisms for Aβ‐induced neurotoxicity and some recent advances in the development of Aβ‐related therapeutic strategies. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Solid phase synthesis of partially protected tocinoic acid: Optimization with respect to resin and protecting groups
Authors: Hlaváček Jan , Ragnarsson Ulf 
Published: January 2005

AbstractA few solid phase and solution approaches of good repute were applied in parallel with the aim to provide optimized routes to Boc‐ and Fmoc‐tocinoic acid (3aand3c) and the corresponding Tyr(But) derivatives (3band3d). Boc‐tocinoic acid is known to couple with tripeptide amides to give substituted oxytocin precursors in high yields, requiring only Boc‐cleavage to furnish the corresponding hormone analogs with minimal loss of material. For comparison, two protected linear hexapeptides (2aand2b) were prepared on three polystyrene supports, two with acid‐labile handles and one a conventional chloromethylated resin, in yields of 62–82 and 58–76%, respectively. The intermediate2acould be converted to3awith physical data in agreement with those earlier reported. Similarly, the intermediate2bwas converted to3b. The highest yields for both2aand2bwere obtained with a 2‐chlorotrityl chloride resin, which in addition provided advantages with respect to overall speed and convenience. Additional syntheses of3cand3don this and of3con SASRIN resin, in conjunction with trityl instead of benzyl for side‐chain protection of cysteine, were also elaborated. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
The asymmetry of the lobe contrasts in two‐beam TEM as a test to obtain the Burgers vector of an inclined relaxing dislocation
Authors: Belgacem Chokri Hadj , Ati Abdelaziz , Bonnet Roland 
Published: January 2005

AbstractIt is suggested that, if the elastic relaxation effect of an inclined dislocation at both free surfaces of a thin plate is taken into account, the determination of its Burgers vector b in two‐beam transmission electron microscopy can be obtained with a notable reduction of experimental work. The relaxation effect produces in general an asymmetric aspect of the lobe contrasts, with respect to a medium line perpendicular to the dislocation image segment. Indeed, from a re‐examination of about twenty micrographs of dislocations located in two different materials, it is concluded that a single experimental image is often sufficient to derive b. In no case three experimental images obtained with non‐coplanar diffracting vectors were found necessary to obtain unambiguously b.
The influence of non‐classical electromagnetic fields on persistent currents
Authors: Dajka J. , Szopa M. , Vourdas A. , Zipper E. 
Published: January 2005

AbstractPersistent currents in mesoscopic rings or cylinders are very sensitive to non‐classical properties of the driving magnetic flux. In the paper we investigate the influence of the quantum and classical noise on the properties of currents. We also study the current characteristics in the presence of maximally entangled states (Bell states) of the non‐classical electromagnetic field. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The role of paths in Robinson–Schensted algorithm (RS), and Kerov, Kirillov and Reshetikhin bijection (KKR)
Authors: Jakubczyk D. , Lulek B. 
Published: January 2005

AbstractIn this work we want to amplify the RS algorithm in the language of paths. Thus, it is a continuation of the previous work [Lulek et al., to appear in Mol. Phys.], where the magnetic interpretation of RS algorithm was given. We also want to present the intermediative role of paths in bijection between standard Young tableaux and rigged configurations. We will treat the paths as a “bridge” which allow us to move between this two objects. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Doping induced crossover between site‐centered stripe phase and bond‐centered stripe phase of cuprates
Authors: Macia¸g A. , Wróbel P. 
Published: January 2005

AbstractUsing a combination of the bond formalism with the recursion method of calculating the Green's function of hole moving in the antiferromagnet (AF) spin 1/2 background we evaluate the energy of a single bond‐centered, bond‐ordered stripe and compare with the energy of a site‐centered stripe. By taking into account the width change of AF domains separated by hole‐rich domain walls (DWs) we find that the crossover between the phase of site‐centered stripes and the phase of bond‐centered stripes takes place upon doping the 2D spin 1/2 AF. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron–phonon coupling in photo‐induced phase transitions
Authors: Radosz A. , Ostasiewicz K. , Magnuszewski P. , Radosiński Ł. , Kusmartsev F. V. , Samson J. H. 
Published: January 2005

AbstractCharge transfer and spin conversion compounds are most spectacular examples of systems exhibiting photo‐induced phase transitions. In that class of systems, thermal phase transition might also be light (or pressure) induced. Though the driving mechanism of a photo‐induced phase transition appears to be electron–phonon coupling, an approach incorporating that coupling within a unified model has not yet been formulated. Two types of treatments, regarding electrons as localised and delocalised are generally considered. We briefly present existing approaches and discuss the main result. The problem of searching common features in thermodynamic properties of such a class of compounds is introduced and the methods in case of charge transfer systems are outlined. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Remote Fermi level induced ferromagnetic transition in GdAl2–Ag system
Authors: Matlak M. , Molak A. , Pietruszka M. , Ślebarski A. 
Published: January 2005

AbstractWe utilize an electrical set‐up consisting of GdAl2 ferromagnetic sample connected to a silver contact electrode where the a.c. voltage is applied only to the latter one. By measuring the a.c. resistivity of Ag electrode vs temperature in the vicinity of the Curie point we observe Fermi level induced phase transition in the Ag electron gas in the form of a kink. This measurement confirms the results anticipated earlier theoretically and obtained also experimentally for Cr–Cu, Gd–Ag, Cr–Ag, TiNi–Ag and CuZnSn–Ag systems. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure and magnetism of Fe3–xMnxAl alloys
Authors: Pugaczowa‐Michalska M. , Go A. , Dobrzyński L. 
Published: January 2005

AbstractThe electronic structure of Fe3–xMnxAl and the effect of local environment on formation of local magnetic moments are examined using self‐consistent spin‐polarised TB‐LMTO method. The electronic properties of the Fe3–xMnxAl compound have been calculated for the supercell structure with 32 atoms and in the range 0 ≤ x ≤ 0.5. The values and orientations of magnetic moments of the iron and the manganium atoms are presented. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pattern formation in the Falicov–Kimball model
Authors: Maśka Maciej M. , Czajka Katarzyna 
Published: January 2005

AbstractIt is known that in the ground state of half‐filled Falicov–Kimball model immobile particles form a checkerboard pattern. On the other hand, there is a wide range of model parameters, for which this model is expected to exhibit a phase separation. Using Monte Carlo simulations we demonstrate how the system reaches these states, as the temperature is lowered. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)