Search

In three separate studies, the efficacy of a single treatment with a 12.5% pyriprole spot-on solution was investigated against induced infestation with Ixodes ricinus, Dermacentor reticulatus and Rhipicephalus sanguineus on dogs (both sexes; Beagles in Studies 1 and 2, mixed-breed in Study 3). For each tick species, one group of 8 dogs left untreated (Studies 1 and 2) or treated with a placebo solution (Study 3) was compared with another group treated once with the spot-on solution at a dose rate of at least 12.5 mg/kg. The dogs were infested with 50 unfed adult ticks of the respective species at various time-points before and after treatment and the surviving attached and unattached ticks were recorded 48 h after re-infestation. For each tick species, efficacy was assessed for each time-point and cumulatively for the whole evaluation period. The dogs were submitted to general health observations and clinical assessments during the study. Efficacy against I. ricinus and R. sanguineus was 100% during the whole evaluation period of 30 days. For D. reticulatus cumulative efficacy for the 30 days after treatment was 98.9%. The product was well tolerated by all the animals.

The efficacy of a single treatment with a 12.5% pyriprole spot-on formulation against induced infestations with R. sanguineus ticks and cat fleas (C. felis) as well as its persistence after repeated washing and shampooing was investigated in four separate studies. In a first study on R. sanguineus involving 32 beagle dogs, the efficacy at various time-points during the 30 days that followed treatment assessed 48 h after re-infestation ranged from 100% to 99.3%. No engorged ticks, alive or dead, were found in the treated animals. Shampooing 2 days after treatment and weekly washings did not affect the efficacy. In a second study on R. sanguineus involving 32 beagle dogs, the efficacy at various time-points during the 30 days that followed treatment assessed 48 h after re-infestation ranged from 100% to 96.8%. Single washing 8 h after treatment and single shampooing 24 h after treatment had no negative impact on the efficacy of the product. In a third study on C. felis involving 28 beagle dogs, the efficacy at various time-points during the 30 days that followed treatment assessed 48 h after re-infestation was always 100% and weekly washings did not diminish the efficacy. In a last study on C. felis involving 24 beagle dogs, the efficacy at various time-points during the 5 weeks that followed treatment assessed 48 h after re-infestation ranged from 100% to 99.8%, and shampooing 24 h after treatment did not reduce the efficacy. The product was well tolerated by the dogs.

The inhibitory activities of fipronil (10% (w/v) solution), (S)-methoprene (9% (w/v) solution), and fipronil/(S)-methoprene (10 and 9% (w/v) solution, respectively) combination against eggs and emerging adult cat fleas (Ctenocephalides felis) and adulticidal activity were tested on experimentally infested dogs. Thirty-two Beagle dogs were selected for this study and eight replicates of four animals were formed based on body weight within sex. One dog in each replicate was randomly allocated to treatment with: (1) untreated control; (2) fipronil 10% (w/v) solution, (3) (S)-methoprene 9% (w/v) solution, and (4) fipronil 10% (w/v) and (S)-methoprene 9% (w/v) combination solution. Treatments were applied once topically on Day 0 at the rate of 0.067 ml/kg. On Days -12, -1, 21, and weekly to Day 84 each dog was infested with approximately 200 fleas and comb counted approximately 24h later, or 2 days (our 48 h) after in the case of Day -1 infestation. On Days -11, 1, 22, and weekly to Day 85 each dog was again infested with approximately 200 fleas. Flea eggs were collected over approximately 24 h beginning 3 days after infestation. Fleas were combed off of the dogs and counted at the end of the egg collection period (approximately 96 h count). One aliquot of up to about 100 eggs, if available, from each animal at each infestation time was incubated for approximately 72 h to determine larval hatch and the other for 35 days to determine the number of adults that developed. The 10% (w/v) fipronil spot-on provided excellent control (>95%) of adult fleas on dogs for 5 weeks. Similarly, the combination spot-on of 10% (w/v) fipronil and 9% (w/v) (S)-methoprene provided excellent control of adult fleas, i.e., >95% for 5 weeks. From week 6 post-treatment onward, the relatively low inhibition of adult flea emergence substantiated the lack of significant ovicidal/larvicidal activity in the fipronil (10%, w/v) treatment group. However, the combination product provided excellent (>90%) ovicidal activity for 8 weeks and high (91.4%) inhibition of adult flea emergence for 12 weeks. In addition, a synergistic effect of the two compounds in combination was demonstrated with fipronil enhancing the ovicidal and inhibition of adult flea emergence activity of (S)-methoprene against cat flea eggs. When all stages of the life cycle of the cat flea are considered, the combination spot-on product provided a high level of total flea control yielding a curative effect against adult fleas and inhibition of flea development stages with little to no potential reinfestation pressure on the animal or in the environment for 12 weeks.

The efficacy of selamectin against adult ascarids was evaluated in eight controlled and masked studies in dogs. Three laboratory studies evaluated selamectin against experimentally induced infections of Toxocara canis ; three laboratory studies evaluated selamectin against naturally acquired infections of T. canis ; one laboratory study evaluated selamectin against naturally acquired infections of both T. canis and Toxascaris leonina ; one field study evaluated selamectin against naturally acquired infections of ascarids ( T. canis and/or T. leonina ) in dogs presented as veterinary patients. Selamectin was administered topically to the skin of dogs in unit doses designed to deliver a minimum of 6 mg kg −1 (range, 6–12 mg kg −1 ). In all studies, dogs were allocated randomly to treatment assignments (selamectin or vehicle control in laboratory studies: selamectin or reference product in the field study) on the basis of pretreatment fecal egg counts. For induced infections, there were significant reductions in geometric mean numbers of adult T. canis after a single application of selamectin (93.9–98.1%, P =0.0001), after two monthly applications (≥88.3%, P ≤0.0001), and after three monthly applications (100%, P ≤0.0002). In the natural infection laboratory studies, when selamectin was administered twice at an interval of 30 days, the percentage reductions in geometric mean numbers of adult T. canis at necropsy were 84.6, 91.3, and 97.9%, and when selamectin was administered on days 0, 14, and 30, the percentage reductions were 91.1 and 97.6%. Geometric mean fecal T. canis egg counts were reduced by ≥92.9% ( P ≤0.0067) at the end of the studies. In the field study, geometric mean fecal ascarid egg counts were reduced by 89.5 and 95.5% ( P =0.0001) for 14 and 30 days, respectively, after a single treatment with selamectin, and by 94.0% ( P =0.0001) 30 days after the second treatment with selamectin. These reductions compared favorably with the egg count reductions from dogs treated with a reference product containing praziquantel, pyrantel embonate, and febantel. There were no adverse drug experiences or treatment-related mortalities during any of the studies. Selamectin, when administered topically in a unit dose providing a minimum dosage of 6 mg kg −1 , was safe and effective against adult T. canis and T. leonina and in reducing the fecal excretion of T. canis eggs in dogs.

Seven controlled studies were conducted to investigate the efficacy of selamectin against weekly infestations of dogs with Rhipicephalus sanguineus and Dermacentor variabilis. Treatments (selamectin or vehicle alone) were applied topically at weekly, 2-week, or monthly intervals or in a "Monthly Plus" regimen (monthly treatment with an additional treatment at 14 days after the first treatment). Selamectin was supplied in unit dose tubes designed to deliver a minimum dosage of 6mgkg(-1). The studies ranged in duration from 37 to 90 days. Fifty adult ticks (+/-2) were applied approximately weekly, and tick counts were performed 3, 4, and 5 days after each infestation. The efficacy of selamectin was expressed as the percentage reduction in geometric mean tick counts on selamectin-treated dogs compared with those for dogs treated with the vehicle alone (negative-control). In one study, the engorgement of Dermacentor variabilis was assessed by weighing ticks after removal on the fifth day after each infestation. Weekly and 2-week interval treatments with selamectin provided efficacies against R. sanguineus of >89% across the entire study periods, with 100% efficacy being achieved from 21 days after the first dose and thereafter (study duration, 37 days for the weekly regimen and 44 days for the 2-week interval regimen). D. variabilis also was well controlled by the 2-week interval treatment regimen, with >96% efficacy being achieved from 21 days after the first treatment and thereafter until the end of the study (study duration: 90 days). In five of six studies incorporating three treatments at monthly intervals, the percentage reduction in R. sanguineus and D. variabilis counts 5 days after infestation ranged from 90 to 100% in the second and third months after treatment began. In the sixth study, reductions of > or =95% in D. variabilis counts 5 days after infestation were achieved for 2 weeks after each treatment in the second and third months. For the Monthly Plus regimen, from the second treatment (day 14) onwards, selamectin achieved 83-100% reductions in R. sanguineus and D. variabilis counts 3 days after infestation, and 94-100% reductions 5 days after infestation in three of the four studies. In the fourth study, selamectin demonstrated good efficacy against D. variabilis for 2 weeks after each treatment. In all seven studies, the counts from the selamectin-treated dogs were significantly (P< or =0.018) lower than those from the vehicle-treated dogs on 77 of the 80 assessments made 5 days after infestation. Selamectin also significantly (P< or =0.0105) reduced engorgement of female D. variabilis. These studies demonstrated that selamectin, administered topically to the skin in a single spot at a minimum dosage of 6mgkg(-1) at monthly intervals, was effective in the control of experimentally induced R. sanguineus and D. variabilis infestations on dogs.

Perennial crops are particularly vulnerable to climate given their exposure to fluctuating weather conditions throughout the year. Key climate-influenced vulnerabilities include winter chill fulfillment, springtime freeze risk, pollination, heat stress, and disease and insect pest pressure. Other contributions to vulnerability include changes in consumer demand, competing land uses, and competition with other production regions. Although climate-related risk varies with crop type and location, recent trends observed for a number of perennial crops and locations include earlier dates of phenological stages and a reduction in chilling hours. Changes in fruit quality and the frequency of damaging spring freeze events are less consistent between locations and cultivars. Assessments of the impact of climate on perennial crop production need to move beyond the local–regional scale, and recognize that perennial crops constitute an international market system with multiple production regions that differ in terms of climate vulnerability.

The thermodynamic equilibria and kinetic aspects of gold dissolution in iodide electrolytes have been studied with emphasis on the effect of different oxidants on the system. In conjunction with kinetic measurements, the chemix computer program was used to predict the concentration profiles of the predominant species at equilibrium in different solution conditions for the systems Au-I−-I2-H2O and Au-I−-OCl−-H2O. The thermodynamic study showed that I3− is the predominant oxidants species in both systems. However, if the concentrations of OCl− and I− are equal, solid iodine is formed. In these systems iodide (I−)_is used to form I3− (responsible for the gold oxidation) and more free iodide needed for the gold complexation is destroyed in the I−-OCl− system than the I−-I2 system. The formation of solid AuI also explains the lower rate of gold dissolution determined for certain conditions in the kinetic study. The thermodynamic modelling supports the kinetic measurements which show that, although the I−-OCl− system has a higher oxidation capacity, it does not extract gold as well as the I−-I2 system. In all cases there exist optimum oxidant/iodide ratios for achieving maximum gold extraction rates. A mixture which has the highest I3− and free I− concentration will attain the best gold extraction rate.

The increased amount of telephony and computer data traffic over single optical fiber lines and the desire to reduce redundancy to decrease capital cost have led to an increased need for high reliability components both in terrestrial and submarine markets. The authors describe a multiclad coupler process which has been used to develop ultra-high reliability couplers suitable for undersea applications. A new packaging process using a new low expansion composite wrap and LCP housing was required to achieve the optical and mechanical stability required. Extensive thermal and mechanical tests of the couplers and packaging materials predict excellent performance over the planned 27 year lifetime of these components. >

Abstract As Gulf of Mexico reservoirs are depleted, well abandonments are becoming a greater financial liability to operators in offshore waters. Some of the liability can be offset by developing more efficient abandonment procedures that can utilize well bores for the disposal of NORM (Naturally Occurring Radioactive Material). In the offshore area, well abandonments can be a significant expense due to the cost of workover rigs. Development of abandonment procedures which do not involve a workover rig can reduce the overall cost of the operation. With minor modifications, these cost effective procedures can be designed to include the downhole disposal of NORM. In addition to controlling costs, an equally important issue for well abandonments and NORM disposal is the overall integrity of the operation. If the procedure is improperly designed and develops problems, an operator can be exposed to many long term safety and environmental risks. In many cases, the expense associated with these risks can far outweigh any short-term savings. With proper design, NORM disposal can be included in offshore well abandonments without compromising the integrity of either operation. Introduction Innovative abandonment procedures for many depleted wells in the OCS-Gulf of Mexico can be integrated with NORM disposal to reduce the overall cost. In developing these procedures, specific emphasis was placed on conducting both operations without a workover rig. The procedures presented in this paper were initially designed for offshore well abandonments. Production tubing in each well abandonment was left in the well bore and utilized as a work string to conduct all downhole cementing operations. Once the cementing operations were complete, a crane was used to remove sufficient tubing and production casing to place a cement plug near the surface. Modification of this abandonment operation to include NORM disposal offers a high degree of isolation with limited incremental cost. These modifications include the disposal of NORM waste that can be mixed and pumped downhole as a slurry along with the disposal of solid material that can be encapsulated and placed in the wellbore. P. 419^

The progressive osteopenic changes in tibial compact bone in adult male monkeys (Macaca nemestrina) were examined histologically during chronic studies of immobilization. The animals were restrained in a semirecumbent position, which reduces normally occurring stresses in the lower extremities and results in bone mass loss. The longest immobilization studies were of 7 months duration. Losses of haversian bone tended to occur predominantly in the proximal tibia and were characterized by increased activation with excessive depth of penetration of osteoclastic activity. There was no apparent regulation of the size and orientation of resorption cavities. Rapid bone loss seen during 10 weeks of immobilization appeared to be due to unrestrained osteoclastic activity without controls and regulation, which are characteristic of adaptive systems. The general pattern of loss persisted throughout 7 months of immobilization. Clear-cut evidence of a formation phase in haversian bone was seen only after 2 months of reambulation. During this period osteoblasts accumulated within resorption cavities, and there was matrix apposition. Within 6 months of recovery there was increased bone turnover, and resorption cavities with diameters of 500-1500 micron were filled partially with new bone; the mean wall thickness of new bone was 2 to 3 times larger than normal. In addition there were numerous remodeling sites that were of normal size and orientation. Trabecular bone was lost during immobilization, and it is probable that losses of large trabecular plates are not replaced, and consequently original bone volume in the cross section is not recovered. In this immobilization model we observed bone resorption occurring for long periods without apparent interruption.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantification of collagen cross-links of monkey bone (tibia), from various time periods of immobilization (up to 7 months) and their subsequent reambulation (up to 40 months) was determined. Results indicated reducible cross-link concentrations markedly increased and peaked at the seven-month period of immobilization and returned to control values after 40 months of recovery. Chromatographic profiles of the major cross-linked peptides indicated that the increased cross-linking after seven months immobilization occurred between residue Hyl ald -16 c as well as Lys ald -16 c of the α1 chains and residue 87 Hyl of α chains of type I collagen. Mature, stable cross-link concentrations as well as their molecular loci remained constant throughout immobilization and reambulation. These results strongly suggest that rapid new bone collagen synthesis occurred during the osteoporotic state due to immobilization. With long-term recovery, the rate of collagen synthesis apparently returned to match the control bone.

In comparing a control vs. a sewage-affected nearshore site off southern California, the natural relative abundances of 13C, 15N and D in Dover sole and Ridgeback prawn muscle were found to be significantly different. This between-site shift in animal isotope abundance is of the type expected if sewage organic materials were an important food source for animals in the latter site. Use of stable isotope natural abundance to trace the incorporation and movement of sewage-derived organics in marine food webs is suggested.

The effect of high temperature post oxidation annealing on deep and shallow electron traps in thermally grown SiO2 on silicon was studied using the avalanche injection method. N2 or Ar anneal leads to removal of water related traps; some of the 5 × 10−19 cm2 deep centers persist during this treatment and shallow traps with cross sections in the 10−16 and 10−15 cm2 ranges are generated. These same deep and shallow traps are found on samples with poly Si gate which have been subjected to a high temperature post deposition anneal. Upon filling the shallow traps at 100 K part of the charge is being transferred to the 5 × 10−19 cm2 trap at this temperature. The observed behavior suggests that at least a substantial fraction of these traps are levels belonging to the same defect center. A brief O2 anneal at high temperature suffices to considerably reduce the density of the 5 × 10−19 cm2 deep and the shallow centers. It is proposed that the traps are caused by oxygen deficiency of the SiO2 and are O3Si· ·SiO3 and/or single O3Si· centers. Additional centers (O3SiO· ·SiO3; O3SiO· and O3Si·) may result from the split off of water from the oxide.

L'echantillonnage porte sur une large collection d'invertebres, poissons et mammiferes des eaux cotieres du sud de la Californie et des eaux pelagiques entre Costa Rica et l'ile Cocos. Mise en evidence d'un leger mais progressif accroissement du 13 C/ 12 C dans les tissus des animaux (muscle) lorsque croit le niveau trophique. Interet de ces resultats dans l'etude des biocenoses