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Following indirect-drive experiments which demonstrated promising performance for low convergence ratios (below 17), previous direct-drive simulations identified a fusion-relevant regime which is expected to be robust to hydrodynamic instability growth. This paper expands these results with simulated implosions at lower energies of 100 and 270 kJ, and ‘hydrodynamic equivalent’ capsules which demonstrate comparable convergence ratio, implosion velocity and in-flight aspect ratio without the need for cryogenic cooling, which would allow the assumptions of one-dimensional-like performance to be tested on current facilities. A range of techniques to improve performance within this regime are then investigated, including the use of two-colour and deep ultraviolet laser pulses. Finally, further simulations demonstrate that the deposition of electron energy into the hotspot of a low convergence ratio implosion through auxiliary heating also leads to significant increases in yield. Results include break even for 1.1 MJ of total energy input (including an estimated 370 kJ of short-pulse laser energy to produce electron beams for the auxiliary heating), but are found to be highly dependent upon the efficiency with which electron beams can be created and transported to the hotspot to drive the heating mechanism.

As part of the development of the beam imaging system at the European Spallation Source, luminescent screens have been fabricated by the flame spraying of scintillating materials onto stainless steel backings. A total of seven screens were produced, three of chromia alumina (Al2O3:Cr), two of YAG (Y3Al5O12:Ce) and two of a 50/50 mix of these. The properties of these screens under proton irradiation were evaluated using a 2.55 MeV proton beam at currents of up to 10 A. Irradiation times were up to 25 h per sample, during which luminescence-, spectrographic-, thermal- and current-data was sampled at a rate of 1 Hz. Preliminary results of these measurements are reported here; with a quantitative analysis presented for one of the chromia alumina screens and a qualitative comparison of all three material types. The luminescent yield for chromia alumina was determined to be around 2000 photons/MeV for a virgin screen, and was found to drop to 1.5% after 167 mC of proton irradiation. A recovery of the luminescence of chromia alumina to >60% was observed after beam current was reduced for an 8 h period. Observations indicate that the YAG and mixed composition screens retain higher luminescence than the chromia alumina even at temperatures of over 200 °C. It is indicated that the luminescence from YAG feeds the R-lines of chromia alumina in the mixed composition screens.

The yield and fuel compression trends for the NIF indirect-drive cryogenically-layered DT implosions is empirically examined across all ablators (CH, C and Be) and design in-flight adiabats between 1.5 and 3. Higher compression is observed for a lower design adiabat. Within a design adiabat, compression increases for shorter coast implosions but only if have optimized shock timing. The sensitivity of compression to coast time appears less for higher adiabat designs. Across all designs and ablators, the best DT neutron yields follow the same 1D theoretical curve versus peak velocity, but only if normalize by capsule scale rather than fuel mass and thickness. Shots with reduced yields can be explained by having long coast time, high hot spot mix or know capsule imperfections. Repeat “Standard Candle” shock timing and gas implosions, and DT layered implosions normalized for scale and velocity, reveal adequate reproducibility in shock timing, implosion drive symmetry, compression and yield for the majority of shots. The level of reproducibility is also consistent with known uncertainties and imperfections in initial laser and capsule parameters and outputs. We thus conclude there is no evidence of a significant random unknown variable in these NIF implosions. The scaled yield reproducibility is such that the effect of design improvements increasing yield on any given shot by at least 40% can be deemed statistically significant.

A significant step transition between seasonally stratified and destratified hydrographic conditions occurred during an October 2008 cruise to the Florida Panhandle Shelf along a cross-shelf transect that was sampled before and after a cold front passed through the area. Meteorological measurements from nearby ocean and land-based stations characterized the event. Cross-shelf continuous Acrobat profiles and discrete CTD stations characterized water column hydrographic patterns, while mid-shelf multicorer and box corer samples characterized sediment texture and nutrients. Water samples collected from selected depths biased toward the sediment interface were analyzed for nutrient content and phytoplankton community composition. Pre-front, the cross-shelf water column exhibited vertical stratification with complex temperature and salinity patterns. A prominent near-bottom chlorophyll a maximum of ∼1.5 μg L −1 between the 25–35 m isobaths occurred with the 1% light level at ∼18 m depth and a near-bottom nitrate+nitrite ( NO 3 − +NO 2 − ) maximum >3 μM between the 30–40 m isobaths. HPLC-determined phytoplankton community composition in the near-bottom chlorophyll a maximum consisted of gyroxanthin-containing dinoflagellates ( Karenia brevis ) and less abundant diatoms, both verified by FlowCAM analysis, mixed with detectable cryptophytes and chlorophytes. Sediment trends based on limited core replicates suggested the sediments were a potential source of nutrients to near-bottom populations of K. brevis and that shell hash could provide abundant pore space for K. brevis incursions. Between the 40–50 m isobaths, diatoms, cryptophytes and chlorophytes dominated near-bottom, gyroxanthin-containing dinoflagellates and prasinophytes occurred throughout the water column, and cyanophytes dominated near-surface. Post-front, the cross-shelf water column exhibited destratification with temperature and salinity increasing offshore. A chlorophyll a maximum of ∼0.75 μg Chl a L −1 left the sediment between 25–35 m isobaths and extended offshore especially in the lower water column with the 1% light level at ∼15 m depth and NO 3 − +NO 2 − concentrations ∼2 μM to the 60 m isobath. HPLC-determined phytoplankton community composition of the offshore plume retained the signature of gyroxanthin-containing dinoflagellates and chlorophytes. Between the 30–50 m isobaths, prasinophytes increased in the lower water column, while cyanophytes increased at all depths across the shelf. The observed step transition from stratification to destratification on the Florida Panhandle Shelf contributed to altered phytoplankton community patterns in response to predominant downwelling favorable winds. Pre-front, K. brevis cells were broadly distributed cross-shelf, but concentrated near-bottom between the 25–35 m isobaths and staged for prolific bloom seeding in response to the upwelling favorable west winds more typical of spring-summer. Post-front, K. brevis cells were mixed throughout the mid-shelf water column and were staged for diffuse bloom seeding in response to either the downwelling or upwelling favorable winds occurring fall-winter. Cyanophytes located predominantly near-surface offshore pre-front, were ubiquitous cross-shelf and more closely associated with K. brevis post-front.

Measurement of the fill pattern of synchrotron storage rings is important for several reasons, including checking the quality of the injection system and the generation of special fill patterns for time-resolved experiments. For the new national X-ray facility based on the Diamond 3 GeV electron storage ring, it is planned to measure the beam quality in a short time of several minutes by using a time-correlated single photon counting method. The method has very good time resolution (50 ps) and high dynamic range (more than six orders of magnitude). In this paper, we describe our experimental setup, a series of tests to evaluate the system limitations using short pulse lasers on laboratory test benches, the existing SRS national X-ray facility, and the third-generation synchrotron radiation facility SLS. Taking all these results together, we are able to predict the system performance for Diamond.

Dilution of semen to low cell numbers/dose can result in a bull-dependent reduction in the post-thaw viability of cryopreserved bovine spermatozoa. It is possible that essential seminal plasma components are lacking at the greater dilution rates, thereby contributing to the deleterious effects of semen dilution. Ejaculates of 6 Holstein bulls were diluted to 120 x 10(6) sperm/mL in an egg yolk citrate extender (EYC). Split samples were further diluted to 80, 40, 20 and 4 x 10(6) sperm/mL in EYC extender with (+SP) and without (-SP) the addition of frozen/thawed seminal plasma previously obtained from a vasectomized bull. Serial dilutions for the +SP treatments were calculated and performed such that each dilution contained a volume of seminal plasma equal to the original 120 x 10(6) sperm/mL dilution. Samples were then loaded into 0.5-mL French straws yielding final sperm concentrations of 30, 20, 10, 5 and 1 x 10(6)/dose. Straws from each dilution were analyzed using 2 stain combinations: the sperm viability stain, SYBR-14 and propidium iodide (PI); or the mitochondrial-specific, membrane potential-dependent stain JC-1 along with PI. Split-plot analysis of variance indicated that within bulls, there were greater proportions of viable spermatozoa in aliquots containing added seminal plasma than in aliquots without added seminal plasma (P0.05). Contrast analyses showed that sperm viability significantly decreased as sperm concentration decreased in the -SP samples. Although the dilution effect was also observed in the +SP samples, the magnitude of the effect was less than in the -SP samples. At most sperm concentrations, the proportions of spermatozoa that stained with JC-1 were correlated (r0.84; P0.05) with the percentages of SYBR- 14 stained spermatozoa. Furthermore, the proportions of JC-1-stained spermatozoa were greater in the +SP aliquots than in the -SP samples at a concentration of 10 x 10(6) sperm/0.5 mL. These results suggest that the addition of seminal plasma can be beneficial to sperm viability when semen is diluted to low cell numbers/dose.

The present approach for thermal management in metallic railgun armatures relies on using the thermal capacity of the armature material to limit the adiabatic temperature rise during launch. In this, the armature is designed so that, as the accelerating current passes through it, the armature heats up to a maximum temperature that is close to the melting point of the armature material. Careful attention to design has to be exercised in regard to local inhomogeneities where current concentrations and associated temperature excursions may occur. Alternatives to this approach are discussed in this paper. These include the possibilities of conductive gaseous cooling and utilization of the latent heat of evaporation of materials contained within the armature. Further work on these concepts is recommended.

A series of randomized, controlled and masked field studies was conducted in veterinary patients to evaluate the efficacy of selamectin, a novel avermectin, in the treatment of naturally occurring Sarcoptes scabiei infestations on dogs and Otodectes cynotis infestations on dogs and cats. A total of 342 dogs and 237 cats participated in these studies, which were conducted at 40 veterinary practices in the USA and Europe. Animals were randomly assigned to treatment with selamectin or a positive-control product (existing approved products). Selamectin was administered as a unit dose providing a minimum of 6mgkg(-1) (range: 6-12mgkg(-1)) in a topical preparation applied to the skin in a single spot on day 0 (O. cynotis in cats, n=144), or on days 0 and 30 (O. cynotis and S. scabiei in dogs, n=83 and n=122, respectively). The presence of parasites was assessed before treatment and at 30 days (for all studies) and 60 days (for O. cynotis and S. scabiei dog studies) after first treatment. The animals were also evaluated clinically at each assessment period. Based on skin scrapings, the efficacy of selamectin against S. scabiei infestations on dogs was >95% by day 30, and 100% by day 60. Against O. cynotis, selamectin eliminated mites in 94-100% of cats by day 30, and in 90% of dogs by day 60. The positive-control products achieved similar results. Thus, selamectin was safe and effective against ear mites in dogs and cats and sarcoptic mange in dogs when used in field (veterinary patient) studies in dogs and cats of a wide variety of ages and breeds.

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.

In a series of six controlled studies (four in dogs, two in cats), heartworm-free dogs and cats were inoculated with Dirofilaria immitis larvae (L(3)) prior to topical treatment with the novel avermectin selamectin or a negative control containing inert formulation ingredients (vehicle). Selamectin and negative-control treatments were administered topically to the skin at the base of the neck in front of the scapulae. In dogs, selamectin was applied topically at dosages of 3 or 6mgkg(-1) at 30 days post-inoculation (PI), or of 3 or 6mgkg(-1) at 45 days PI, or of 6mgkg(-1) at 60 days PI. Cats were treated topically with unit doses providing a minimum dosage of 6mgkg(-1) selamectin at 30 days PI. Of the animals that were treated 30 days PI, some dogs were bathed with water or shampoo between 2 and 96h after treatment, and some cats were bathed with shampoo at 24h after treatment. Between 140 and 199 days PI, the animals were euthanized and examined for adult D. immitis. Adult heartworms developed in all control dogs (geometric mean count, 18.7 worms) and in 88% of control cats (geometric mean count, 2.1 worms). Selamectin was 100% effective in preventing heartworm development in dogs when administered as a single topical dose of 3 or 6mgkg(-1) at 30 days after infection, 3 or 6mgkg(-1) at 45 days after infection, or 6mgkg(-1) at 60 days after infection. Selamectin was 100% effective against heartworm infections in cats when administered as a single topical unit dose of 6mgkg(-1). Bathing with water or shampoo between 2 and 96h after treatment did not reduce the efficacy of selamectin as a heartworm prophylactic in dogs. Likewise, bathing with shampoo at 24h after treatment did not reduce the efficacy of selamectin in cats. These studies demonstrated that, at the recommended dosage and treatment interval, a single topical administration of selamectin was 100% effective in preventing the development of D. immitis in dogs and cats.

Contents Eight bull ejaculates were split to evaluate the effects of glycerol on sperm organelle function. Although glycerol protects sperm membranes during cryopreservation, preliminary data suggested that glycerol was detrimental to sperm organelles to varying degrees. To assess the compartmental effects, three organelle-specific fluorophores were used to analyze with (G+) and without glycerol (G–) in spermatozoa stored for 24 h at 5°C in an egg-yolk-based extender. The mitochondrial probe, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl benzimidazolylcarbocyanine iodide (JC-1) was used to examine the level of mitochondrial metabolic function by it’s discrimination between high (J-aggregate staining, red-orange) and low membrane potentials (JC-1 monomeric staining, green); while acosomal reacted spermatozoa were identified using fluorescein-labelled lectin from arachis hypogaea, PNA-FITC. The proportions of living and dead spermatozoa were determined by staining with the combination of SYBR-14 and propidium iodide (PI). Split-plot analysis of variance revealed that within bulls, glycerol altered the proportions of sperm staining with each organelle-specific fluorophore to varying degrees. The proportion of spermatozoa labelled with SYBR-14, indicating intact plasmalemmae, were not affected by the addition of glycerol (p = 0.11). Although the total proportion of JC-1-labeled spermatozoa were similar in G– and G+ samples (p = 0.90), the presence of glycerol decreased the proportion of spermatozoa that exhibited J-aggregate staining (p

The mitochondrial probe 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolyl-carbocyan ine iodide (JC-1) not only identifies mitochondria exhibiting low membrane potentials by the emission of green fluorescence (range, 510-520 nm) but also differentiates these from mitochondria exhibiting relatively high membrane potentials. This discrimination occurs because JC-1 forms aggregates at high membrane potentials. These J-aggregates emit a bright red-orange fluorescence at 590 nm. In this study, JC-1 was combined with the classical dead cell stain, propidium iodide (PI), to identify a spectrum of functional sperm along with degenerate sperm. Flow cytometric analysis of bull sperm showed that the aggregate:monomer ratio differed among bulls before cryopreservation (P 0.05). The effects of stain equilibration time, sperm concentration, and live:dead ratios were examined. The addition of SYBR-14 to the JC-1 and PI combination enhanced the distinction between the red PI-stained and red-orange JC-1-stained populations. This discrimination between J-aggregates and the PI-stained sperm was affected by sperm concentration. These studies show that JC-1 can be useful in monitoring mitochondrial function in bovine sperm.

Summer porewater and spring and summer surficial sediment samples were collected from 26 locations in the intertidal region of the Fraser River estuary. Porewaters were analysed for dissolved iron and manganese (as defined by species 50μm). Concentrations of organic matter declined from the mouth to the foreslope of the estuary. With the exception of RED Fe, temporal variation (May vs July) was insignificant (P>0·05, three-way ANOVA). Concentrations of RED Fe recovered from the surficial sediments were in general greater in the summer vs spring months, although spring and summer values were highly correlated (Pearson Product Moment Correlation Coefficient; PPCC; r=0·89;P

The green fluorescent protein (GFP) of the jellyfish Aequorea victoria offers certain advantages over other bioluminescence systems because no exogenously added substrate or co-factors are necessary, and fluorescence can be elicited by irradiation with blue light without exposing the cells producing GFP to invasive treatments. A mycobacterial shuttle-plasmid vector carrying gfp cDNA was constructed and used to generate transcriptional fusions with promoters of interest and to examine their expression in Mycobacterium smegmatis and Mycobacterium bovis BCG grown in macrophages or on laboratory media. The promoters studied were: (i) ahpC from Mycoosis and Mycobacterium leprae, a gene encoding alkyl hydroperoxide reductase which, along with the divergently transcribed regulator oxyR, are homologues of corresponding stress-response systems in enteric bacteria and play a role in isoniazid sensitivity; (ii) mtrA, an M. tuberculosis response regulator belonging to the superfamily of bacterial two-component signal-transduction systems; (iii) hsp60, a previously characterized heat-shock gene from M. bovis; and (iv) tbprc3, a newly isolated promoter from M. tuberculosis. Expression of these promoters in mycobacteria was analysed using epifluorescence microscopy, laser scanning confocal microscopy, fluorescence spectroscopy, and flow cytometry. These approaches permitted assessment of fluorescence prior to and after macrophage infection, and analyses of promoter expression in individual mycobacteria and its distribution within populations of bacterial cells. Bacteria expressing GFP from a strong promoter could be separated by fluorescence-activated cell sorting from cells harbouring the vector used to construct the fusion. In addition, the stable expression of mtrA-gfp fusion in M. bovis BCG facilitated localization and isolation of phagocytic vesicles containing mycobacteria. The experiments presented here suggest that GFP will be a useful tool for analysis of mycobacterial gene expression and a convenient cell biology marker to study mycobacterial interactions with macrophages.

Increased free intracellular calcium ([Ca(2+)](i)) in adipocytes blunts the lipolytic response to catecholamines by activating phosphodiesterase 3B - the same enzyme that mediates the antilipolytic effect of insulin - while also compromising the efficiency of insulin-stimulated glucose uptake. Physiological increases in parathyroid hormone (PTH) have been shown to increase [Ca(2+)](i) in adipocytes. These considerations may rationalize recent evidence that high dietary intakes of calcium and/or dairy products may reduce risk for obesity, diabetes, and insulin-resistance syndrome, and they predict that other dietary measures which down-regulate PTH - such as good vitamin D status, and moderation in phosphate and salt intakes - may likewise be beneficial in these respects. Consistent with this position are reports that body weight is elevated in elderly subjects with both primary and secondary hyperparathyroidism; furthermore, insulin resistance is a well-known complication of both forms of hyperparathyroidism. The fact that regular alcohol consumption is associated with decreased PTH secretion may help to explain why moderate drinkers are less prone to insulin resistance, diabetes, and - in women - obesity. Down-regulation of PTH cannot be expected to promote dramatic weight loss, but in the long-term it may lessen risk for significant weight gain and diabetes, and conceivably may potentiate the fat loss achievable with caloric restriction and/or exercise.

The feasibility of generating higher order harmonics from a free electron laser (FEL) amplifier with a tabletop system is investigated. The system is based on a small period undulator able to wiggle femtosecond short electron bunches over several tens of periods. Harmonic generation is obtained using a FEL system as a prebuncher for a 0.1 nC, 10 to 100 MeV electron bunch, which radiates in the second undulator tuned to a higher harmonic of the FEL. Simulations of the process, using the General Particle Tracer code with a new element that takes into account the radiation from particles, are presented.

The efficacy of a novel avermectin, selamectin, was evaluated against naturally acquired aural infestations of Otodectes cynotis on dogs and cats. In four controlled and masked studies conducted in the USA and Europe, animals were allocated randomly to treatment with either selamectin at a minimum dosage of 6mgkg(-1) (range, 6-12. 5mgkg(-1)) or the vehicle only from the commercial formulation of selamectin (negative control). Treatments were administered topically in a single spot to the skin of each animal's back at the base of the neck in front of the scapulae. Cats were treated on day 0 only, and dogs were treated either on day 0 only or on days 0 and 30. The ears of dogs were examined otoscopically on day 14 for the presence of viable mites. Mite counts were conducted on day 30 for animals that had received one dose and on day 60 for animals that had received two doses. Percentage reductions in geometric mean mite counts for selamectin treatment compared with the vehicle were 100% for all animals on all count days. Analysis of variance, confirmed by Savage Scores, showed that ln(mite count+1) values were significantly (P< or =0.0015) lower for selamectin than for the vehicle for all animals on all count days. Thus, selamectin administered topically at a minimum dosage of 6mgkg(-1) was safe and 100% effective against naturally acquired aural infestations of O. cynotis in dogs and cats after a single dose or after two doses administered 1 month apart.

A series of randomized, controlled, masked field studies was conducted to assess the efficacy and safety of selamectin in the treatment of flea infestations on dogs and cats, and in the prevention of heartworm infection in dogs. In addition, observations were made on the beneficial effect of selamectin treatment on dogs and cats showing signs of flea allergy dermatitis (FAD). In all studies selamectin was applied topically, once per month, in unit doses providing a minimum dosage of 6mgkg(-1). Dogs and cats with naturally occurring flea infestations, some of which also had signs associated with FAD, were assigned randomly to receive three months of topical treatment with selamectin (220 dogs, 189 cats) or a positive-control product (dogs: fenthion, n=81; cats: pyrethrins, n=66). Selamectin was administered on days 0, 30, and 60. Day 0 was defined as the day that the animal first received treatment. Flea burdens were assessed by flea comb counts and clinical evaluations of FAD were performed before treatment, and on days 14, 30, 60, and 90. On days 30, 60, and 90, mean flea counts in selamectin-treated dogs were reduced by 92.1, 99.0, and 99.8%, and mean flea counts in fenthion-treated dogs were reduced by 81.5, 86.8, and 86.1%, respectively, compared with day 0 counts. Also, on days 30, 60, and 90, mean flea counts in selamectin-treated cats were reduced by 92.5, 98.3, and 99.3%, and mean flea counts in pyrethrin-treated cats were reduced by 66.4, 73.9, and 81.3%, respectively, compared with day 0 counts. Selamectin also was beneficial in alleviating signs in dogs and cats diagnosed clinically with FAD. A total of 397 dogs free of adult heartworm infection from four heartworm-endemic areas of the USA were allocated randomly to six months of treatment with selamectin (n=298) or ivermectin (n=99). Selamectin achieved a heartworm prevention rate of 100%, with all dogs testing negative for microfilariae and adult heartworm antigen on days 180 and 300. Selamectin was administered to a total of 673 dogs and 347 cats having an age range of 6 weeks to 19 years (3954 doses). The animals included 19 purebred or crossbred Collies (Bearded, Border, and unspecified). There were no serious adverse events. Results of these studies indicated that selamectin was highly effective in the control of flea infestations in dogs and cats without the need for simultaneous treatment of the environment or of in-contact animals and also was beneficial in alleviating signs associated with FAD. Selamectin also was 100% effective in preventing the development of canine heartworms and was safe for topical use in dogs and cats.

A series of randomized, controlled, masked, field (veterinary patient) studies were conducted in the USA and Europe to evaluate the efficacy of selamectin, a novel macrocyclic lactone of the avermectin subclass, in the treatment of naturally acquired gastrointestinal nematode infections in cats. After confirmation of ascarid and/or hookworm infection, 298 cats of various ages and breeds were randomly assigned to treatment with selamectin ( n =202) or an existing commercially approved positive-control product ( n =96). Unit doses of selamectin (providing a minimum dosage of 6 mg kg −1 ) were administered topically to the skin in a single spot at monthly intervals. Quantitative fecal examinations were performed on days 0 (before treatment), 30, and 60. In the selamectin-treated cats, fecal ascarid egg counts were reduced by 99.6 to 100% on day 30, and by 99.9 to 100% on day 60. Fecal hookworm egg counts were reduced by 98.3% on day 30, and by 100% on day 60 in the selamectin-treated cats. The positive-control products achieved reductions in egg counts of 96.5 to 100% (ascarids) and 98.9 to 99.9% (hookworms). These studies have shown that monthly topical administration of selamectin is safe and highly effective in the treatment of naturally acquired ascarid and hookworm infections in cats.

Mobil Exploration and Producing U. S. ("Mobil") currently uses two different types of steam splitter devices to divide the main steam supply among the steam drive injection wells. The steam splitter's job is to take an incoming stream and divide it into several smaller streams of approximately equal steam quality. The performance of a horizontal dead-end tee steam splitter was compared to a horizontal ring steam splitter to determine which type of splitter did the best job of providing equal quality splits. Performance data from both splitters were taken using a portable test separator while each splitter was in service. The test data show that both splitters provide roughly equal splits among their wells and that neither splitter has a performance advantage. Cost and operating data is presented which will aid the decision as to which type of splitter is appropriate for a given steamdrive project.

The objectives of this study are to evaluate the compatibility of the MHD insulating materials boron nitride and silicon nitride in a potassium environment at temperatures of 1000 and 1400{degrees}F (538 and 760{degrees}C, respectively) and to measure the electrical conductivities of the specimens before and after exposure to potassium. Based on the test results, an assessment is to be made of the suitability of these materials for application as insulator materials in an MHD channel.

Seven genotypes of lima bean seeds at three maturity stages were analyzed by HPLC for the monosaccharide, fructose; the disaccharide, sucrose; the oligosaccharides, raffinose, stachyose, and verbascose; and the polysaccharide, starch. As maturity and size of the seeds increased, the concentrations of fructose and sucrose decreased while raffinose, stachyose and verbascose increased. No significant differences were found in the starch concentration. The concentration of the carbohydrates did not correlate with cotyledon color, seed color or growth habit. Sufficient variability existed in the oligosaccharide concentration in the investigated genotypes that reduction of the flatulence promoters (raffinose, stachyose and verbascose) might be possible by breeding.

The transcription of ribosomal genes in a cell line (Kc) derived from female D.melanogaster, has been investigated using hybridization probes prepared from restriction fragments of a cloned rDNA repeat with a 5 kb type I [Wellauer et al. (1978) Cell 14, 269-278] intron. Gels, of nuclear RNA that have been transferred to diazotized paper and hybridized with labelled intron sequences, reveal both large (1-10 kb) transcripts and a discrete 325 base species. Berk-Sharp experiments [(1977) Cell 12, 721-732] reveal large transcripts that are homologous to intron sequences and extend into 28S sequences as well. However, while the abundance of 28S transcripts is about 50,000 copies per nucleus [Clark et al. (1977) Genetics 86, 789-800], these long transcripts are only present at 1-2 copies per nucleus and the 325 base species is only 10 times more abundant. In view of the fact that female cells have about 400 rDNA genes, 49% of which have type I introns, one must conclude either that transcription rarely occurs from the genes containing introns (the majority) or these transcripts are processed unusually rapidly. Transcripts homologous to the "non-transcribed spacer" region have been found, but their abundance is no higher.

The T5 bacteriophage DNA molecule, unlike the molecules from T2, P1, λ and T7 bacteriophage, contains interruptions at specific locations in both of its polynucleotide chains. When the molecule is denatured, it gives rise to polynucleotide chains which sediment in at least four different zones. By contrast, denatured T2, P1, λ and T7 DNA sediment as unimodal zones. The lengths of the polynucleotide chains -which comprise these zones were calculated through use of a relationship established for determining the relative lengths of polynucleotide chains from their rate of sedimentation in alkaline sucrose gradients. The positions of the interruptions along the molecule are under the genetic control of the phage and apparently are not a property of the host. The phenomenon is seen in another phage, PB, which is closely related to T5. The interruptions in the molecule are probably gaps in the polynucleotide chains. This conclusion was reached because the chains are not intact when the molecule is denatured in formamide, a mild organic denaturing agent. A number of models were proposed for ways in which the six polynucleotide chains could be arranged to form the intact duplex molecule. Two reannealing experiments were performed which confirmed some general features which all of the models had in common. The existence of gaps in the T5 DNA molecule helps to explain some earlier observations on the structure of the molecule and suggests interpretations for other results concerning its biological function.

The DNA molecules isolated from mature particles of the temperate bacteriophage P22 are linear and double stranded, with a molecular weight of 26 to 27 million. The linear structure remains unaffected by annealing treatments of the sort that will cyclize the DNA molecules of the λ-related temperate bacteriophages. However, P22 DNA that has been partially degraded by exonuclease III does cyclize on annealing. This indicates a duplex terminal repetition of base sequence in P22 DNA, in contrast to the complementary single-stranded terminals found in λ. The length of the repeated region can be estimated to comprise 2.5 to 5.0% of the P22 DNA molecule. Full-length circular molecules can be produced also by denaturing and then re-annealing P22 DNA. This process is dependent upon complete separation of the two single chains on denaturation, and suggests that the DNA molecules released by individual P22 phage particles are circular permutations of one another. In support of this conclusion, competition-annealing experiments indicate that short fragments derived from the ends of P22 DNA contain all of the seqences present in a complete molecule. Therefore, the number of different cyclic permutations is large, and possibly equal to the number of base pairs in the genome.

The first internode stems of 8-week-old Biggs (resistant) and Nebraska-10 (susceptible) safflowers ( Carthamus tinctorius ) were wound-inoculated with Phytophthora drechsleri and held at 30 °C. Safynol ( trans-trans -3,11-tricecadiene-5,7,9-triyne-1,2-diol), an antifungal polyacetylene, was extracted from infected stems. The concentration of safynol increased rapidly in the stems of Biggs in the first 48 h after inoculation, and was relatively constant during the next 48 h. In the susceptible variety, the concentration of safynol increased rapidly in the first 24 h and decreased in the next 72 h. A concentration of 30 μg ml −1 which completely inhibited the growth of the fungus in vitro was reached at the portal of infection in Biggs stems 48 h after inoculation. The highest concentration at the portal of infection for Nebraska-10 (17μg g −1 fresh weight) wass reached 24 h after inoculation. Loss of water from infected Nebraska-10 stems was much greater than from infected Biggs stems.

The molecular weight calculated from the variance of the gaussian distribution of DNA molecules at equilibrium in a CsCl density gradient appears to be one-half the best estimates of the true molecular weight. This is true for unbroken DNA molecules from T2, T4, T5, P22 and T7 bacteriophages. It follows that, when this factor is taken into account, the calculated molecular weight is a good measure of actual molecular weight for unbroken genetically uniform molecules. This uniform proportionality between calculated molecular weight and the best estimates of the true molecular weight suggests that there is no detectable density heterogeneity in these unbroken molecules, or that there is a contribution by density heterogeneity which increases precisely as 1/ M for these molecules of different origins. This is a rather special requirement which renders this alternative unlikely. Shear-produced fragments of T2 DNA give broader bands than would be expected on the basis of whole molecules of comparable size. The calculated molecular weights of these fragments are approximately one-fourth the best estimates of the true molecular weights. It turns out that the observations are just what one would expect if some of the fragments were slightly richer in GC than others. The magnitude of this compositional heterogeneity, its dependence on fragment size and its possible significance are discussed. The formaldehyde-stabilized polynucleotide chains produced by denaturing the fragments have band-width molecular weights which are two-thirds those of the fragments from which they were derived. This is exactly what would be expected if the two chains of the duplex had the same density and the molecular weight is halved when the duplex fragment is denatured and separated into polynucleotide chains.

A column has been devised which fractionates duplex DNA segments of about 200,000 molecular weight with respect to their characteristic denaturation temperature and hence composition. This fractionation has been applied to a number of different phage and bacterial DNA's and the degree of compositional heterogeneity measured. The segments show a relatively broad distribution and the composition of segments from one species of DNA overlap those from another. This is in contrast with the compositions of high molecular weight segments which show high species specificity. This fractionation procedure has been applied to λ DNA, and the composition of some genetically deleted segments has been determined.

A study has been made of intracellular P22 DNA under conditions that favor lysogeny. After infection with radioactively labeled phage, a large fraction of the linear parental DNA is converted into a fast-sedimenting form that exhibits the properties of a covalently closed circular duplex or superhelix. These properties include an elevated sedimentation rate in strand-separating solvents and the production of a slower-sedimenting circular molecule after treatment with pancreatic DNase. The closed circular molecules were purified on the basis of their ability to renature spontaneously following alkaline denaturation. The superhelical nature of this DNA was confirmed by subsequent examination in the electron microscope and the screw-sense of the tertiary turns was shown to be right-handed. A second, less abundant form of P22 DNA appeared to consist of two inter-locked superhelical molecules. The kinetics of the incorporation of [3H]thymidine reveal that DNA synthesis precedes the formation of superhelical DNA molecules; most of these molecules are formed after DNA synthesis ceases. Superhelical molecules seem to be efficiently formed from both parental and newly made DNA. The number of phage equivalents of newly synthesized, superhelical DNA was estimated as 10 to 20 per cell under the conditions used.

The intrinsic viscosity (at zero gradient, zero concentration) of osmotically disrupted T4 bacteriophage has been measured. For a variety of reasons it seems likely that there is very little DNA-protein aggregation in dilute solutions and the measurable viscosity is due to the DNA molecules alone. The magnitude of the intrinsic viscosity is unaltered by changing the growth conditions, or exposing the infected bacteria to moderate doses of X-rays or added 32 P β -decay irradiation. This would mean that the DNA molecules are neither stuck together nor broken down by these treatments. Therefore, if these conclusions are correct, the large subunit as seen by autoradiography of the same material is not a consequence of the labelling process.

Electrical activity can be recorded extracellularly from contracting heart cells in vitro with the electrodes of 30-element microelectrode arrays built into the culture chambers. The arrays are fabricated in the laboratory by etching thin metal films deposited on glass coverslips; the fabrication employs techniques developed by the microelectronics industry.

The phenol-extracted DNA from phage was subjected to various procedures which disrupt the hydrogen bonds, but do not break any of the ester linkages. This denatured DNA reacts rapidly with formaldehyde and, once reacted, there is no tendency to “renature” or re-establish the former hydrogen bonded structure. These formaldehyde-reacted polynucleotide chains have been examined by density-gradient centrifugation and the band width and band form are compared with the same quantities measured on the undenatured molecules. The results indicate that the molecular weight of the single polynucleotide chains is very high, and in no case lower than one-half that of the undenatured molecules from which they are derived. If this is correct, it means that the polynucleotide chains which make up the large undenatured molecules of 62 × 10 6 mol. wt. consist of only two continuously-linked polynucleotide chains. This conclusion bears on current ideas of genetic recombination.