bluuebunny/crossref_metadata_2025_split huggingface dataset:
The efficiency of methanol for the extraction of some herbicide residues from soil
Authors: Cotterill Edward G. 
Published: November 2006

AbstractMethanol was more efficient than solvent systems based on acetonitrile or chloroform for the extraction of a number of weathered herbicide residues from soil. The presence of water in the soil improved recovery. Methanolic extracts, on examination by gas‐liquid chromatography, also gave lower background levels than the extracts with other solvents.
Further studies on amitraz as a veterinary acaricide
Authors: Harrison Ian R. , Palmer Bryan H. 
Published: November 2006

AbstractRecent research on the control of animal ectoparasites with amitraz is summarised and reference made to its expellent action. Tickicides are an essential requirement for the rearing of cattle in tropical and sub‐tropical regions. The use of amitraz in these areas is well documented. More recently advantage has been taken of its broad acaricidal and insecticidal spectrum to develop the compound for use against lice, keds and, in particular, mites parasitic on farm animals. The outstanding miticidal activity of amitraz has been shown to extend to demodectic mange on dogs. Field trials in Central Europe and the Mediterranean region are used to illustrate the problem of animal pest control within the limits imposed by established farm practices. Finally, mention is made of some attempts to utilise the pesticidal properties of amitraz in less conventional ways, including pasture spraying for the control of ticks.
Kinetics of chemical degradation of organophosphorus pesticides; hydrolysis of chlorpyrifos and chlorpyrifos‐methyl in the presence of copper(II)
Authors: Blanchet Pierre‐F. , St‐George Augustin 
Published: November 2006

AbstractThe kinetics of the hydrolysis reactions of chlorpyrifos‐methyl and chlorpyrifos, in the presence of copper(II), have been measured in buffered aqueous solutions. For each reaction, a rate law of the type ‐d[pesticides]/dt= k2[pesticides][Cu2+] was observed. As the concentration of copper(II) increased, a corresponding increase in the rate of hydrolysis was observed until the concentration of copper(II) reached about 1.0 × 10−2M. At this point, the rate of hydrolysis became independent of the concentration of copper(II) in both reactions. Using the experimental data, a mechanism for each reaction is proposed, in which the copper(II) ion forms a six‐membered ring complex with the nitrogen in the ring structure and the sulphur of the phosphorothioate moiety. The rate of hydrolysis increased with increasing pH. At higher pH values, precipitation of Cu2+ was observed and general base‐hydrolysis reactions became more and more important. The differences in the rate constant observed is explained using the inductive effect theory of the alkyl group.
The mode of action of S‐benzyl O, O‐di‐isoproyl phosphorothiaote and of dicloran on aspergillus nidulans
Authors: Craig Gordon D. , Peberdy John F. 
Published: November 2006

AbstractS‐Benzyl O, O‐di‐isopropyl phosphorothoiate (IBP) and dicloran inhibit spore germination and mycelial growth in Aspergillus nidulans. The physiological and biochemical effects of both fungicides were studied at their Ec50 values (EC50 is the concentration that inhibits mycelial growth by 50%). IBP inhibited chitin synthase activity in vivo and in vitro and this appeared to be the primary mode of action, although it also caused a slight decrease in total lipid synthesis. Dicloran caused an increase in nucleic acid synthesis, particularly RNA synthesis, but a decrease in total lipid biosynthesis.
Herbicide residues in waste waters from ricefields
Authors: Cabras Paolo , Diana Paolo , Meloni Marco , Pirisi Filippo M. , Pirisi Renzo 
Published: November 2006

AbstractThe herbicides bentazone, 2,4‐D, MCPA, propanil, molinate, and tiocarbazil, and the insecticide phenthoate, were applied to ricefields in Sardinia at rates equivalent to maximum aqueous concentrations of 0.4‐2.8 mg kg−1, assuming the water to be 20 cm deep. Their concentrations in water were measured by high‐performance liquid chromatography. Residues in 162 water samples, collected from 16 ricefields 1, 4, 7, 10, 12, 18, 21 and 120 days after the last spraying, were all below the limit of determination (0.03 mg kg−1). Residues in 40 water samples taken from five drainage canals were also less than 0.03 mg kg−1.
Fungicidal activity of substituted quinoxalines
Authors: Carter Geoffrey A. , Clark Terence , James Carolyn S. , Loeffler R. S. Thomas 
Published: November 2006

AbstractTwenty substituted quinoxalines based on the structure of 6 (or 7)‐methyl‐3‐phenyl‐1, 2‐dihydroquinoxalin‐2‐one, a fungicidally active photodegradation product of quinomethionate, were synthesised. Eleven of these compounds had ED50 values, as protectant sprays against Podosphaera leucotricha, of 0.1 mmol or less; these compounds had an aromatic substituent at the 3‐position of the quinoxaline ring. They were less active as protectant leaf dips against Erysiphe graminis f. sp. hordei than against Podosphaera leucotricha; none showed any systemic activity as a soil‐applied treatment against Podosphaera leucotricha. One compound was more active than quinomethionate as an eradicant spray. In spore germination tests on fungi from different taxonomic groups, the quinoxaline derivatives were active against only one basidiomycete (Uromyces fabae), whereas quinomethionate showed a broad spectrum of activity. The possible significance of this difference in spectrum of activity with respect to the mode of action is discussed.
Action of bioresmethrin on the corpus cardiacum of Locusta migratoria
Authors: Singh Gur Jai Pal , Orchard Ian 
Published: November 2006

AbstractThe action of the pyrethroid insecticide bioresmethrin on the corpus cardiacum (CC) has been studied in Locusta migratoria. Bioresmethrin increased the spontaneous electrical activity recorded from both the glandular and storage lobes, and induced repetitive discharge in these lobes in response to single electrical stimulation of the nervus corpus cardiacum II (NCC II) and NCC I, respectively. Incubation of the isolated CC in low concentrations of bioresmethrin (0.1‐1.0 μmol) induced the release of bioassayable hyperlipaemic hormone. Injection of bioresmethrin into locusts was found to induce an elevation in the haemolymph lipid at a stage when there was no overt symptom of poisoning. It is concluded that bioresmethrin may act directly on the CC of locusts to modulate electrical activity and induce the release of hormones. The effects may precede overt symptoms of poisoning.
Pyridazinones as bioregulators in crop protection
Authors: Rittig Falk R. , Becker Rainer , Bleiholder Hermann , Feichtmayr Franz , Haedicke Erich , John Judith B. St. 
Published: November 2006

AbstractSubstituted pyridazinones induced specific decreases in the linolenic acid content accompanied by increases in the linoleic acid content of plant membranes. The ratio of linoleic acid to linolenic acid was used to establish structure‐activity correlations for a series of about 50 different substituted pyridazinones. The most active compound found was 4‐chloro‐5‐dimethylamino‐2‐phenylpyridazin‐3‐one. X‐ray structural analysis of this compound yielded three types of crystals differing in their molecular parameters. Application of computerised cluster analysis confirmed the specific biological activity of selected groups of compounds. Electron‐density calculations yielded substituents with specific activity on the linoleic acid/linolenic acid ratio. Correlation of this ratio, produced by different substituted pyridazinones, can be used to search for potentially more active compounds. Treatment of plants, moulds and insects with pyridazinones led to interesting results of importance to agriculture, and confirmed the bioregulator activity of some of these compounds.
Insect hormones and growth regulators
Authors: Jennings Richard C. 
Published: November 2006

AbstractThe endocrine system that controls development and reproduction in insects has many unique features that could provide targets for insecticides with novel modes of action. Such insecticides, which act by disrupting the growth and development, are often called insect growth regulators. Three components of the endocrine system are discussed in this context, and an example of the specific chemical disruption of one of them, which could form the basis for the development of such insecticides, is described.
The relationship of metabolism studies to the modes of action of herbicides
Authors: Kirkwood Ralph C. 
Published: November 2006

AbstractMetabolism studies are necessary in the understanding of the mode of action of herbicides, their loss of activity and their selectivity. Molecular change of a herbicide may involve photochemical degradation, and non‐enzymic or enzymic reactions that normally inactivate, but in some cases activate, a compound. Molecular change resulting in activation is discussed with regard to the (2,4‐dichlorophenoxy)‐alkanoic acids, the pyridines paraquat and diquat, the anilides benzoylprop‐ethyl and flamprop‐methyl, and the thiocarbamates. Inactivation due to metabolism is reviewed with regard to herbicides applied to soil and foliage. Of the soil‐applied herbicides, the 1,3,5‐triazines and the nitrile dichlobenil are exemplified as cases in which selectivity may be due largely to interspecific differences in metabolism. Of the foliage‐applied translocated compounds, the metabolism of the phenoxyalkanoic acid herbicides has been extensively investigated and may involve conjugation, side‐chain degradation or extension, ring hydroxylation and protein binding. The mode of action of glyphosate, asulam, dalapon and aminotriazole in perennial weeds is discussed with particular reference to their metabolism.
Synthesis and juvenile hormone activities of some new ether derivatives of hydroquinone
Authors: Massardo Pietro , Bettarini Franco , Piccardi Paolo , Longoni Angelo 
Published: November 2006

AbstractA new class of compounds, derived from hydroquinones, has been synthesised and bioassayed for juvenile hormone activity on yellow mealworm (Tenebrio molitor), confused flour beetle (Tribolium confusum), and mediterranean flour moth (Anagasta kuehniella). Structure‐biological activity relationships of the most significant products are tabulated and discussed. Two of the new compounds, 1, 4‐bis(5‐chloropent‐4‐ynyloxy) benzene (I) and 1‐(5‐chloropent‐4‐ynyloxy)‐4‐phenoxybenzene (II), showed outstanding activity in morphogenetic assay with T. molitor, and good field persistence. Product II is of particular interest for the control of various Homopteran species, mosquitoes, stored product pests and fire ants.
The use of small enclosures to assess the toxic effects of cypermethrin on fish under field conditions
Authors: Shires Stephen W. 
Published: November 2006

AbstractAn emulsion concentrate formulation of cypermethrin (‘Ripcord’) was applied at seven different dose rates (between 5 and 500 g a. i. ha−1) to the water surface of 1‐m3 stainless steel enclosures, located in a small outdoor pond, to which were introduced small rainbow trout and common carp. A range of water quality parameters were monitored frequently in all of the enclosures and in the open pond. At daily intervals, the concentration of cypermethrin was determined in water samples, collected from the enclosures treated with 5, 50 and 500 g a. i. ha‐−1. Two further water samples were collected from these enclosures, and their toxicity was assessed by bioassay, using Gammarus pulex as the test organism. The experiment was terminated 96 h after application, when all the fish were removed and examined for mortality or adverse toxic effects. Throughout the study, the water quality parameters in all the enclosures remained similar to those recorded in the open pond. Cypermethrin residues, in the enclosures treated with 5 and 50 g a. i. ha−1, attained peak concentrations 24 h after application, and thereafter declined to about 50% of this level. Maximum cypermethrin concentrations were not attained until about 72 h after application in the enclosure treated with 500 g a. i. ha−1. Highly consistent responses, closely correlated with the applied dose rates, were obtained with G. pulex and both species of fish. Rainbow trout appeared to be about three times more susceptible to cyper‐methrin than common carp, with calculated LD50 values of 92 and 300 g a. i. ha−1, respectively. It is therefore most unlikely that fish mortality would result from the use of cypermethrin in normal agricultural practice.
Development of resistance and cross‐resistance in fenvalerate and deltamethrin selected strains of Spodoptera littoralis (Boisd.)
Authors: Riskallah Medhat R. , Abd‐Elghafar Samir F. , Abo‐Elghar Mohamed R. , Nassar Moustafa E. 
Published: November 2006

AbstractResistances of 33‐ and 27‐fold to the pyrethroids fenvalerate and deltamethrin, respectively, have been induced in larvae of the Egyptian cotton leafworm Spodoptera littoralis (Boisd.) by selection of two subcolonies of a field population in the laboratory. Selected strains showed relatively high levels of resistance (11‐ to 36‐fold) to all the tested pyrethroids, moderate levels of cross‐resistance (3‐ to 13‐fold) to DDT and the carbamate aminocarb, and a slight increase in tolerance levels to endrin and lindane. The pyrethroid‐resistant strains, by contrast, manifested no cross‐resistance to the organophosphorus compounds that were tested. Moreover, a negative crossresistance was observed in the pyrethroid‐resistant strains to dicrotophos, methamidophos and the carbamate methomyl.
The use of dimensional analysis in a study of drop retention on barley
Authors: Lake John R. , Marchant John A. 
Published: November 2006

AbstractDimensional analysis was used to simplify an experimental investigation of the relationship between the variables thought to be involved in the retention process. Equipment was developed for applying drops of known size at a range of velocities to glasshouse‐grown barley leaves. This enabled experiments to be carried out to determine the velocity at which drops of a given size were retained on a leaf. Expressions were developed relating the groups of variables thought to affect retention. From these expressions, a graph was produced which can be used to predict the retention behaviour over the experimental range investigated. For example, if drops (100‐400 μm diameter) of water containing a surfactant are applied at their terminal velocitres to the leaves, it is predicted that (a) smaller drops will be retained better than larger drops, and (b) larger drops will be retained if the surface tension of the spray liquid is reduced.
Studies of plant cuticle and spray droplet interactions: A fresh approach
Authors: Baker Edward A. , Hunt Grace M. , Stevens Peter J. G. 
Published: November 2006

AbstractThe effects of cuticular properties on the impaction and redistribution of aqueous and oil solutions, emulsions and wettable powders were studied using a microapplicator, which dispensed monosize droplets (50‐400 μm), and a range of techniques including scanning electron microscopy, X‐ray analysis and microautoradiography. Lateral and transcuticular movement of active ingredients was monitored by stripping the outermost wax layers and adhering deposits with cellulose acetate films applied as a spray from an acetone solution. Spread factors, determined using fluorescent markers and a reflectance microscope, varied extensively. Oil formulations spread rapidly through layers of crystalline wax whereas aqueous solutions distributed most readily over smooth surfaces. An X‐ray analyser attachment to the scanning electron microscope proved particularly useful for investigating the complex interactions occurring between plant surfaces and diluted e. c. and w. p. formulations. Kamaps and elemental spectra confirmed that lipophilic materials partitioned preferentially into the organic phase which separated as a zone at the outer edge of the droplet residue, whereas water‐soluble compounds concentrated in the central region.
The persistence of spray droplets above two vegetation canopies
Authors: Symmons Philip M. , Dubs Andreas 
Published: November 2006

AbstractDroplets were released from an ‘instantaneous line source’ perpendicular to the wind at heights of 4 and 7 m above the ground. Droplets were collected by rotating samplers at three heights; sets of samplers were positioned in a line parallel to the wind, downwind of the line source. Trials were carried out in moderately unstable conditions during the day, and under stable conditions shortly after dark, both over short rough stubble and over mature cotton. A substantial proportion of the small droplets were found to travel as far as 500 m over cotton; over grass, few of even the smallest droplets were collected 250 and 500 m downwind of the line source. Collection at the distant samplers was on average slightly, but not significantly, more when the spray was released at the greater height.
Anion‐controlled Syntheses and Crystal Structures of a Pair of Novel Azide‐bridged Copper(II) Complexes Constructed from 4‐Chloro‐2‐[(2‐dimethylaminoethylimino)methyl]phenol
Authors: You Zhong‐Lu , Jiao Qing‐Zhu , Niu Shu‐Yun , Chi Jing‐Yun 
Published: November 2006

AbstractA pair of novel azide‐bridged polynuclear copper(II) complexes, [CuL(μ1,1‐N3)]n (1) and [Cu4L2(CH3COO)2(μ1,1‐N3)4] (2) (L = 4‐chloro‐2‐[(2‐dimethylaminoethylimino)methyl]phenolate), have been obtained from the same Schiff base ligand and an identical synthetic procedure using anions of the metal salts as the only independent variable. Complex 1 was synthesized using copper(II) nitrate, while complex 2 was synthesized using the copper(II) acetate as the salt. Both of the complexes show novel supramolecular structures in their crystals as elucidated by X‐ray analyses. The polynuclear complex 1 contains [CuL(μ1,1‐N3)]n units as the building blocks, crystallizes in the Pbca space group. The tetra‐nuclear complex 2 contains [Cu4L2(CH3COO)2(μ1,1‐N3)4] units as the building blocks, crystallizes in the $P{\bar 1}$ space group.
Syntheses, Characterization and Crystal Structures of Three Structurally Similar Dinuclear Schiff Base Cadmium(II) Complexes with Bridging Azide or Thiocyanate Ligands
Authors: You Zhong‐Lu , Jiao Qing‐Zhu , Niu Shu‐Yun , Chi Jing‐Yun 
Published: November 2006

AbstractThree novel Schiff base cadmium(II) complexes, derived from the end‐on (μ‐1,1‐N3) azide or end‐to‐end (μ‐1,3‐NCS) thio cyanate bridges and similar tridentate Schiff base ligands, have been synthesized under similar synthetic procedures and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Cd2(L1)2(N3)2(μ‐1,1‐N3)2] (1), the dinuclear double end‐on azide‐bridged [Cd2(L2)2(N3)2(μ‐1,1‐N3)2] (2), and the dinuclear double end‐to‐end thiocyanate‐bridged [Cd2(L3)2(NCS)2(μ1,3‐NCS)2] (3), where L1, L2 and L3 are three similar tridentate Schiff bases obtained by condensation of 2‐pyridylaldehyde with N,N‐diethylethane‐1,2‐diamine, of 2‐pyridylaldehyde with N‐isopropylethane‐1,2‐diamine, and of 2‐pyridylaldehyde with N,N‐dimethylpropane‐1,3‐diamine, respectively. Each cadmium(II) centre in the complexes is in a distorted octahedral coordination. There is a crystallographic inversion centre in each of the complexes. The similar small ligands used as the secondary ligands in the preparation of the cadmium(II) complexes with similar Schiff bases can result in similar structures.
Involvement of phospholipid molecular species in controlling structural order of vertebrate brain synaptic membranes during thermal evolution
Authors: Kitajka K. , Buda Cs. , Fodor E. , Halver J. E. , Farkas T. 
Published: November 2006

AbstractFluorescence anisotropy parameter of [p‐(6‐phenyl)‐1,3,5‐hexatrienyl]phenyl‐propionic acid (DPH‐PA) and 1‐(4‐trimethylammoniumphenyl)‐6‐phenyl‐1,3,5‐hexatriene (TMA‐DPH) embedded in synaptic plasma membranes prepared from brains of cold (5°C) and warm (22°C) adapted fish (Cyprinus carpio L.), rat (Rattus norvegicus) and bird (Branta canadensis), was studied. Fatty acid composition of total lipids as well as molecular species composition of diacyl phosphatidylcholines and phosphatidylethanolamines was also determined. The amount of long‐chain polyunsaturated fatty acids decreased with increasing body temperature. There was a nearcomplete compensation of membrane structural order for environmental/body tempeature over the evolutionary scale as seen by DPH‐PA. Using TMA‐DPH, the compensation was partial with rat and bird. Since DPH‐PA and TMA‐DPH differ in their charges, it is proposed, that the former reported membrane regions rich in cationic or zwitterionic (neutral) phospholipids and the latter, membrane regions rich in negatively charged phospholipids in the synaptic plasma membranes. Many different molecular species (20–25) of diacyl phosphatidylcholines and diacyl phosphatidylethanolamines were identified. The level of 16:0/22:6 phosphatidylcholine decreased while disaturated phosphatidylcholines increased with increase of environmental/body temperature from the fish through the bird. Level of 1‐monoenoic 2‐polyenoic phosphatidylethanolamines also decreased with an increase in environmental/body temperature. Experiments using vesicles made of mixed synthetic phosphatidylcholine vesicles (16:0/16:0, 16:0/18:1, 16:0/22:6 in various proportions) showed that increase in disaturated phosphatidylcholine species does not explain the observed complete adjustment of membrane structural order in synaptic plasma membranes. Change in level of 1‐monoenoic, 2‐polyenoic phosphatidylethanolamines might be one of the factors involved in controlling the biophysical properties of the membrane according to the temperature.
The effects of lidocaine and hypoxia on phospholipid biosynthesis in the isolated hamster heart
Authors: Wong Jason T. , Man Ricky Y. K. , Choy Patrick C. 
Published: November 2006

AbstractIn this study, the effects of lidocaine and hypoxia on the biosynthesis of phospholipids in the hamster heart were examined. hamster hearts were perfused with [1,3‐3H]glycerol under normal and hypoxic conditions, and in the absence or presence of 0.5 mg/mL lidocaine. After perfusion, the radioactivity incorporated into the various phospholipid fractions was determined. With the exception of phosphatidylcholine, the synthesis of phospholipids was generally stimulated by lidocaine perfusion. In contrast, hypoxia caused a general decrease in phospholipid biosynthesis which was partially restored by lidocaine. ATP and CTP levels were severely reduced under hypoxic conditions, but their levels were not restored by lidocaine treatment. The activities of enzymes for phospholipid synthesis were determined under the various perfusion conditions. The activity of phosphatidic acid phosphatase was elevated by lidocaine and decreased by hypoxic treatment. The activity of CTP:phosphatidic acid cytidylyltransferase was increased under hypoxia, with or without lidocaine. Despite the reduction in phosphatidylcholine biosynthesis, no change in the activity of cytidine diphosphocholine (CDPcholine): diacylglycerol cholinephosphotransferase was detected following lidocaine or hypoxic perfusion. However, enzyme activity was inhibited by the presence of lidocaine in the assay mixture. Our results indicate that the reduction in phospholipid biosynthesis under hypoxic conditions was caused mainly by diminishing high‐energy nucleotide levels. The enhancement of phospholipid biosynthesis by lidocaine appeared to be mediated in part by modulation of enzyme activities.