bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acaricide toxicity and resistance in larvae of different strains of Tetranychus urticae and Panonychus ulmi (Acari: Tetranychidae)
Authors: Nauen Ralf , Stumpf Natascha , Elbert Alfred , Zebitz Claus P W , Kraus Wolfgang 
Published: August 2002

AbstractThe toxicities of eight structurally different acaricidal compounds to six‐legged larvae (first motile stage) of three laboratory strains of the two‐spotted spider mite, Tetranychus urticae, and the European red mite, Panonychus ulmi, were evaluated following spray application. The larvae of five field‐derived strains of T urticae originating from France, Italy, Brazil, California and Florida were also tested for their susceptibilities to discriminating concentrations of several acaricides resulting in 95% mortality when applied to the organophosphate‐resistant laboratory reference strain WI. The spray bioassay used was robust and gave repeatable results with a wide range of acaricidal compounds, irrespective of their mode of action (ovo‐larvicides or primarily acting on motile life stages). Compounds tested were abamectin, azocyclotin, chlorpyrifos, clofentezine, deltamethrin, fenpyroximate, hexythiazox and pyridaben. Larvae of one of the laboratory strains of T urticae, AK, originally collected in Japan in 1996 and maintained without further selection pressure, exhibited 2000‐ and >4000‐fold resistance to the mitochondrial electron transport inhibitors pyridaben and fenpyroximate, respectively. Another strain of T urticae, AU, obtained from Australia and maintained in the laboratory under selection with hexythiazox and clofentezine since 1987 showed >770‐ and >1000‐fold resistance to clofentezine and hexythiazox, respectively. The same resistance pattern was observed against larvae of a laboratory strain of P ulmi, CE, also selected with hexythiazox. Larvae of one of the field‐derived strains of T urticae, BR, showed a lower susceptibility to a number of compounds, whilst the others were susceptible to all compounds except the organophosphates.© 2001 Society of Chemical Industry
The role of glutathione S‐transferases in the detoxification of some organophosphorus insecticides in larvae and pupae of the yellow mealworm, Tenebrio molitor (Coleoptera: Tenebrionidae)
Authors: Kostaropoulos Iason , Papadopoulos Athanasios I , Metaxakis Athanasios , Boukouvala Evridiki , Papadopoulou‐Mourkidou Euphemia 
Published: August 2002

AbstractThe correlation between the natural levels of glutathione S‐transferase (GST) and the tolerance to the organophosphorus insecticides parathion‐methyl and paraoxon‐methyl, as well as the interaction of affinity‐purified enzyme and the insecticides were investigated in order to collect further information on the role of the glutathione S‐transferase system as a mechanism of defence against insecticides in insects. The studies were carried out on the larvae and pupae of the coleopteran Tenebrio molitor L, which exhibit varying natural levels of GST activity.Stage‐dependent susceptibility of the insect against insecticides was observed during the first 24 h. However, 48 h after treatment, the KD50 value increased significantly due to the recovery of some individuals. Simultaneous injection of insecticide with compounds which inhibit GST activity in vitro caused an alteration in susceptibility of insects 24 or 48 h post‐treatment, depending on stage and insecticide used. Inhibition studies combined with competitive fluorescence spectroscopy revealed that the insecticides probably bind to the active site of the enzyme, thus inhibiting its activity towards 1‐chloro‐2,4‐dinitrobenzene in a competitive manner. High‐performance liquid chromatography and gas chromatography revealed that T molitor GST catalyses the conjugation of the insecticides studied to a reduced form of glutathione (GSH). From the above experimental results, it is considered that GST offers a protection against the organophosphorus insecticides studied by active site binding and subsequent conjugation with GSH.© 2001 Society of Chemical Industry
Natural products as insecticides: the biology, biochemistry and quantitative structure–activity relationships of spinosyns and spinosoids
Authors: Sparks Thomas C , Crouse Gary D , Durst Gregory 
Published: August 2002

AbstractThe spinosyns, a novel family of insecticidal macrocyclic lactones, are active on a wide variety of insect pests, especially lepidopterans and dipterans. The biological activity of a mixture (spinosad; Tracer®, Spin‐Tor®, Success®) of the two most abundant spinosyns (spinosyns A and D) against pest insects is on a par with that of many pyrethroid insecticides. The spinosyns also exhibit a very favorable environmental and toxicological profile, and possess a mode of action that appears unique, with studies to date suggesting that both nicotinic and gamma‐aminobutryic acid receptor functions are altered in a novel manner. Compared to pyrethroids such as cypermethrin, spinosyn A is slow to penetrate into insect larvae such as tobacco budworm larvae (Heliothis virescens); however, once inside the insect, spinosyn A is not readily metabolized. To date, more than 20 spinosyns and more than 800 spinosoids (semi‐synthetic analogs) have been isolated or synthesized, respectively. Artificial neural network‐based quantitative structure activity relationship (QSAR) studies for the spinosyns suggested that modification of the 2′,3′,4′‐tri‐O‐methylrhamnosyl moiety could improve activity and several spinosoids incorporating these modifications exhibited markedly improved lepidopteran activity compared to spinosad. Multiple linear regression‐based QSAR studies also suggest that whole molecule properties such as CLogP and MOPAC dipole moment can explain much of the biological activity observed for the spinosyns and closely related spinosoids.© 2001 Society of Chemical Industry
New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two‐spotted spider mite (Tetranychus urticae) in the UK
Authors: Gorman Kevin , Hewitt Fiona , Denholm Ian , Devine Gregor J 
Published: August 2002

AbstractA recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10 000 mg litre−1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross‐resisted by buprofezin‐resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.© 2001 Society of Chemical Industry
Probing the shape of a hydrophobic pocket in the active site of δ‐opioid antagonists
Authors: Santagada Vincenzo , Caliendo Giuseppe , Severino Beatrice , Perissutti Elisa , Ceccarelli Francesca , Giusti Laura , Mazzoni Maria Rosaria , Salvadori Severo , Temussi Piero Andrea 
Published: August 2002

AbstractThe change of selectivity and the induction of antagonism by the insertion of 1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylic acid (Tic) in the second position of several opioid peptides have led to the interpretation of Tyr‐Tic as a specific message domain for δ‐opioid antagonists and to the discovery of dipeptides with substantial opioid activity. Selectivity and activity increase enormously when Tyr is substituted by 2′,6′‐dimethyl tyrosine (Dmt), hinting that the side chain of Dmt fits a hydrophobic cavity of the receptor very tightly and precisely. We have investigated the specificity of this fit by systematic changes of the substituents on the aromatic ring of Tyr. Mono‐ and disubstitutions different from 2′,6′‐ invariably lead to catastrophic decreases of activity. The only substitution compatible with retention of substantial antagonism is 2′‐methyl. An analysis of the conformational properties of all analogues reveals that substitutions do not affect the global shape of the molecule significantly. Accordingly, it is possible to use the shape of the different side chains to map the hydrophobic cavity of the receptor. The resulting complementary image is funnel shaped. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Chloride‐induced corrosion of steel in concrete
Authors: Glass G K , Buenfeld N R 
Published: August 2002

AbstractThe corrosion of steel reinforcement in concrete structures induced by chloride ion contamination is a major problem. Deterioration starts with the loss of protection provided by the concrete cover as the result of chloride ingress. This is followed by corrosion initiation and then propagation. Recent advances in models of chloride penetration into concrete, based on mathematical models of the physical transport processes and an analysis of empirical data, have been made. Inhibitive and aggressive properties of solid phases present at the steel which affect corrosion initiation have been identified. Improved methods have been developed to monitor corrosion rates as well as chloride ingress into the concrete cover. An improved understanding of the deterioration processes has led to new developments in repair techniques.
Protective role of Bacopa monniera on morphine induced hepatotoxicity in rats
Authors: Sumathy T. , Subramanian S. , Govindasamy S. , Balakrishna K. , Veluchamy G. 
Published: August 2002

AbstractThe protective effect of Bacopa monniera on morphine induced liver antioxidant levels was studied in rats. Oral administration of alcohol extracts of Bacopa monniera induced a significant hepatoprotective effect. In the morphine treated group, a significant increase of lipid peroxidation and a significant decrease in liver antioxidant enzyme levels were observed. Simultaneous administration of morphine and Bacopa extract prevented these alterations. The results of this study showed that Bacopa monniera alcohol extract exerted a hepatoprotective effect against morphine induced liver toxicity. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of Mucuna urens (horse eye bean) on the gonads of male guinea‐pigs
Authors: Udoh Paul , Ekpenyong Joseph 
Published: August 2002

AbstractThe effect of Mucuna urens (seeds) on the gonads and sex accessory glands of male guinea‐pigs was investigated. Sexually mature guinea‐pigs of proven fertility were administered orally with 70 mg/kg and 140 mg/kg body weight of crude extract daily for 8 weeks respectively. Phytochemical screening of the seeds revealed the presence of alkaloids. No death or weight loss were observed during the duration of treatment. No pregnancy occurred in females mated with the treated males.Histological observations at high dose (140 mg/kg) showed complete degeneration of sperm in the testicular tubules. In some tubules, the acrosomal cap of the sperm cells was separated from the nuclei which underwent colour changes. In some tubules only the tails were left in the lumen. The spermatids, primary and secondary spermatocytes showed pycnosis while the morphology of spermatogonia and germinal epithelium appeared normal.Some epididymides were devoid of sperm while others contained degenerated spermatozoa and cell debris. In the prostate gland there was collapse of the villi and reduction of secretion in both the prostate and seminal vesicles. At low doses (70 mg/kg), there was spermatogenic arrest at spermatid stage. These observations have shown that M. urens is a potential male antifertility agent. Copyright © 2001 John Wiley & Sons, Ltd.
Qualitative and quantitative olfactometric evaluation of different concentrations of ethanol peppermint oil solutions
Authors: Krone D. , Mannel M. , Pauli E. , Hummel T. 
Published: August 2002

AbstractSelection of an adequate placebo is a major problem in clinical trials of Euminz® (10% peppermint oil/ethanol) which is used topically for the treatment of tension‐type headache. This randomized, controlled, double‐blind, cross‐over study was performed to investigate whether there are qualitative differences between 10%, 1%, 0.5%, 0.1%, and 0% peppermint oil. Forty‐one healthy subjects participated (age range 21–28 years); they rated both intensity, and hedonic tone of the stimuli. Verbal descriptions were combined to multiple response sets (MRS). In addition, the trigeminal impact of odorants was determined. Intensity ratings and MRS ‘menthol like’ and ‘alcohol/solvent’ changed with stimulus concentration. However, intensity had no significant effect on hedonics, trigeminal impact, or the number of descriptive items used. When MRS ‘menthol like’ and ‘alcohol/solvent’ were analysed after being weighted with intensity ratings, changes in relation to stimulus concentration were lost. Thus, the differences between the five concentrations of peppermint oil were—to their largest part—due to changes in stimulus intensity. Considering the large day‐to‐day variability of olfactory sensitivity the present data support the hypothesis that the odour quality of 10% peppermint oil cannot be discriminated from the odour of 0.1%, 0.5%, or 1% peppermint oil when tested on separate days. Copyright © 2001 John Wiley & Sons, Ltd.
In vitroantiprotozoal activity of extract and compounds from the stem bark ofCombretum molle
Authors: Asres K. , Bucar F. , Knauder E. , Yardley V. , Kendrick H. , Croft S. L. 
Published: August 2002

AbstractThe antiprotozoal activity of the Ethiopian medicinal plantCombretum molle(R. Br. ex G. Don.) Engl & Diels (Combretaceae) was evaluated byin vitrotesting againstPlasmodium falciparum, Trypanosoma brucei rhodesiense, Trypanosoma cruziandLeishmania donovani. The acetone fraction of the stem bark of this plant prepared by soxhlet extraction was inactive against the intracellular amastigotes ofL. donovaniandT. cruziin murine peritoneal macrophages but showed significant activity against extracellularT. b. rhodesienseblood stream form trypomastigotes and trophozoites ofP. falciparumwith IC50values of 2.19 and 8.17 μg/mL, respectively. Phytochemical examination of the bioactive fraction resulted in the isolation of two tannins and two oleanane‐type pentacyclic triterpene glycosides. One of the tannins was identified as the ellagitannin, punicalagin, whilst the structure of the other (CM‐A) has not yet been fully elucidated. The saponins that were characterized as arjunglucoside (also called 4‐epi‐sericoside) and sericoside displayed no activity against any of the four species of protozoa tested. On the other hand, punicalagin and CM‐A had IC50values of 1.75 and 1.50 μM, respectively, againstT. b. rhodesienseand were relatively less toxic to KB cells (cytotoxic/antiprotozoal ratios of 70 and 48, respectively). The tannins also showed intermediate activity againstP. falciparum, although their selectivity against these parasites was less favourable than the above. It appears that our findings are the first report of hydrolysable tannins exhibiting antitrypanosomal and antiplasmodial activities. Copyright © 2001 John Wiley & Sons, Ltd.
Quality and reliability information integration for design evaluation of fixture system reliability
Authors: Jin Jionghua (Judy) , Chen Yong 
Published: August 2002

AbstractQuality and reliability are two important factors in manufacturing‐system design. However, the analysis and optimization of manufacturing‐system reliability and product quality are normally conducted separately in practice. There is no general framework to integrate these two important factors, quantitatively analyze the interactions between them, and further study their integrated effects on the manufacturing‐system performance. In this paper, the QR‐Co‐Effect of product/part quality and manufacturing‐system component reliability is investigated in an assembly fixture system. The concept, model and analysis of QR‐Co‐Effect are addressed in this paper. Copyright © 2001 John Wiley & Sons, Ltd.
A performance study for multivariate location and shape estimators
Authors: Wisnowski James W. , Simpson James R. , Montgomery Douglas C. 
Published: August 2002

AbstractExploratory data‐analysis methods and empirical model‐building techniques often attempt to determine the center and spread of multivariate data in order to determine the relative location of observations. The most common measure of multivariate location is the Mahalanobis distance. This measure uses standard mean and covariance matrix estimators for the center and spread. Outliers tend to influence these standard measures such that the corresponding Mahalanobis distances are inappropriately large for data near the true centroid, and relatively small for true outliers. As such, robust measures of location and spread are needed. Many robust measures have been proposed including the minimum covariance determinant, and the minimum volume ellipsoid. It is not clear how these methods perform under various data settings. We perform a comprehensive evaluation of the most referenced methods from the literature. A Monte Carlo simulation study is used to generate data without outliers and data with outliers dispersed separately and in groups or clouds. The methods are evaluated in terms of their ability to detect outliers and their ability not to signal false alarms for clean data. The findings from the study indicate that, although several methods display consistently solid performance, the method of Rocke and Woodruff performs the overall best. Copyright © 2002 John Wiley & Sons, Ltd.
Ab initio molecular modeling of 13C NMR chemical shifts of polymers. 1. Ethylene–norbornene copolymers
Authors: Ragazzi Massimo , Carbone Paola , Ferro Dino R. 
Published: August 2002

AbstractCycloolefin copolymers (COC) have recently raised much interest because of their excellent thermal and optical properties, largely determined by the chain composition and stereochemistry. Previous force‐field computations allowed us to define the main conformational characteristics of ethylene–norbornene (E–N) copolymers and to contribute to the elucidation of their microstructure on the basis of empirical relationships between conformation and 13C nuclear magnetic resonance (NMR) chemical shifts. A thorough test of ab initio 13C chemical shifts computations [gauge‐invariant atomic orbitals (GIAO)] on known cases shows that the agreement with experimental data is quite good, especially with the MPW1PW91 density functional theory (DFT), using the 6‐311+G(2d,p) basis set on properly energy‐minimized structures. We applied this method on proper model compounds to confirm the signal assignment of the spectra of E–N copolymers in the presence of norbornene microblocks, where strong effects arising from ring distortions are expected to occur. The results nicely confirm the latest assignment of norbornene signals belonging to ENNE sequences. This shows the great potentialities of GIAO/DFT computations with regard to complex spectra interpretation and polymer microstructural investigations. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Wannier‐type atomic functions and chemical bonding in crystals
Authors: Smirnov V. P. , Evarestov R. A. , Usvyat D. E. 
Published: August 2002

AbstractA new method of chemical bonding analysis in crystalline solids is suggested. Wannier functions centered on atoms and related to upper valence and lower conduction bands of a crystal [Wannier‐type atomic orbitals (WTAO)] are proposed to play a part of atom‐like functions in population analysis. A straightforward variational procedure is formulated for generation of WTAO from Bloch functions (crystalline orbitals) calculated on a basis of plane waves (PW), LCAO, or any other set of functions. The advantages of the proposed approach compared to the traditional population analysis of Mulliken or Löwdin type on the basis of atomic orbitals are discussed. The proposed approach is applied to analyze the local properties of the electronic structure of Si and GaAs crystals obtained by Hartree–Fock LCAO method. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Density functional study of the relative reactivity in the concerted 1,3‐dipolar cycloaddition of nitrile ylide to disubstituted ethylenes
Authors: Liao Hsin‐Yi , Su Ming‐Der , Chung Wen‐Sheng , Chu San‐Yan 
Published: August 2002

AbstractDensity functional theory was used to perform a theoretical evaluation of (E)‐1,2‐disubstituted ethylenes as dipolarophiles for the 1,3‐dipolar cycloaddition reaction. The reactivities of electron‐withdrawing and ‐donating substituted ethylenes were examined by estimating their activation energies. The calculated activation energies predicted that the most reactive species is (E)‐1,2‐C2H2(NO)2, whereas the least reactive is (E)‐2‐butene. Namely, it was demonstrated that 16‐electron 1,3‐dipole reactants with more electropositive substituents in terminal positions and ethylenes that possess more strongly electron‐withdrawing substituents facilitate 1,3‐dipolar cycloaddition reactions. All of the theoretical results can be rationalized using the configuration mixing model. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 318–323, 2001
The structures and properties of cis‐ and trans‐MeCl2(NH3)2, Me=Pd and Pt complexes, in ground and excited states*
Authors: Hill Glake , Gora Robert. W. , Roszak Szczepan , Leszczyński Jerzy 
Published: August 2002

AbstractStudies of structures, energetics, and charge distribution were performed for ground and lowest excited electronic states of MeCl2(NH3)2, Me=Pd and Pt complexes. Despite the similarity of the Pd and Pt elements, the differences in isomerization energies, ground‐excited state separation energy, and electronic density distribution are significant. The MeN and MeCl bonds possess a different nature with the Cl accepting and the NH3 group donating electrons to the central metal. The bonds are more polarized in Pt‐based complexes. The electronic excitations involve mostly the metal atom, and although they do not change the structure drastically, the excitations do, however, impact the charge distribution. Interaction energy decomposition for the ground state indicates that ammonia–metal interactions are dominated by the energy delocalization term. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 213–219, 2001
Electron structure of polysilanes. Are these polymers one‐dimensional systems?
Authors: Pelikán P. , Košuth M. , Biskupič S. , Noga J. , Straka M. , Zajac A. , Baňacký P. 
Published: August 2002

AbstractElectron structures of polysilane, 1‐methyl polysilane, 1,1‐dimethyl polysilane, 1‐phenyl polysilane, 1,1‐diphenyl polysilane, and 1‐methyl 1‐phenyl polysilane in solid state were calculated using the cyclic cluster orbital method (CCO), based on a Hartree–Fock approach using a quasirelativistic INDO Hamiltonian applied to cyclic clusters. Effect of the redistribution of electron density on the silicon backbone chains after the substitution of hydrogen by methyl and phenyl groups has been investigated. Going from one‐ to three‐dimensional models, significant changes appear in calculated electron distributions, as well as in the band structure topologies of the corresponding polymers. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 157–168, 2001