Failure mechanisms of thermal barrier coatings exposed to elevated temperatures

The failure of a ZrO2-8%Y2O3/Ni-14% Al-0.1% Zr coating system on Rene 41 in Mach 0.3 burner rig tests was characterized. High flame and metal temperatures were employed in order to accelerate coating failure. Failure by delamination was shown to precede surface cracking or spalling. This type of failure could be duplicated by cooling down the specimen after a single long duration isothermal high temperature cycle in a burner rig or a furnace, but only if the atmosphere was oxidizing. Stresses due to thermal expansion mismatch on cooling coupled with the effects of plastic deformation of the bond coat and oxidation of the irregular bond coat are the probable life limiting factors. Heat up stresses alone could not fail the coating in the burner rig tests. Spalling eventually occurs on heat up but only after the coating has already failed through delamination

IMMUNOCONTRACEPTION AND POSSIBLE APPLICATION IN WILDLIFE DAMAGE MANAGEMENT

lmmunocontraception technology appears to have viable application in wildlife damage management. However, administration of these vaccines is presently performed by syringe injection or remote delivery by darts or bio-bullets. In order for immunocontraception to be successful for broad scale application to free-roaming animals, the vaccine must be delivered in an oral form. Recent advances in molecular biology, immunology, and pathology of mucosal infection gives us tools to develop effective oral vaccines. Oral immunocontraceptive vaccine encapsulated in adhesive liposomes or non-virulent live vectors holds promise as a practical approach for immunocontraception of free-roaming wildlife. Issues of safety, species specificity, regulatory constraints, and field application of the vaccine will need to be addressed

Delivery of lmmunocontraceptive Vaccines for Wildlife Management

Immunocontraceptive technology appears to be a viable approach for population control of nuisance species of wildlife. The administration of immunocontraceptive vaccines is presently performed by syringe injection or by remote delivery via darts or biobullets. In order for immunocontraception to be successful in free-roaming animals, the vaccine must be delivered in an oral form. Recent advances in molecular biology, immunology, and pathology of mucosal infections give us tools to develop effective oral vaccines. Oral vaccines encapsulated in either biodegradable microspheres, synthetic adhesive liposomes, or nonvirulent live vectors hold promise as a practical approach for immunocontraception of free-roaming wildlife. Issues of safety, species specificity, and field application of the vaccine will need to be addressed

IMMUNOCONTRACEPTION AND POSSIBLE APPLICATION IN WILDLIFE DAMAGE MANAGEMENT

lmmunocontraception technology appears to have viable application in wildlife damage management. However, administration of these vaccines is presently performed by syringe injection or remote delivery by darts or bio-bullets. In order for immunocontraception to be successful for broad scale application to free-roaming animals, the vaccine must be delivered in an oral form. Recent advances in molecular biology, immunology, and pathology of mucosal infection gives us tools to develop effective oral vaccines. Oral immunocontraceptive vaccine encapsulated in adhesive liposomes or non-virulent live vectors holds promise as a practical approach for immunocontraception of free-roaming wildlife. Issues of safety, species specificity, regulatory constraints, and field application of the vaccine will need to be addressed

WILDLIFE CONTRACEPTION: TARGETING THE OOCYTE

The USDA’s National Wildlife Research Center (NWRC) has successfully researched and developed a number of chemical and immunologically-based wildlife contraceptives. Diazacon™ interferes with cholesterol metabolism and disrupts steroidogenesis, while nicarbazin (registered as OvoControl-P® and OvoControl-G®) disrupts the structure of the vitelline membrane of bird eggs. Immunologically-based agents act to stimulate targeted antibody production. GonaCon™ causes the host’s immune system to bind gonadotropin releasing hormone, preventing ovulation, while SpayVac™ prevents fertilization of the postovulatory oocyte. This kind of target specificity can be highly advantageous. A number of oocyte-only control contraceptive strategies are currently being researched at the NWRC. 4-Vinylcyclohexene diepoxide (VCD) is an industrial chemical which is specifically ovotoxic, depleting the ovarian oocyte pool with repeated exposure. Research into VCD efficacy as well as the comparability of a similar diepoxide, ERL 4221, in rats and pigs is in progress. Immunological inhibition of recently discovered oocyte-secreted proteins which regulate follicular development in mammals is also of interest. Two such proteins, growth differentiation factor 9 (GDF9) and bone morphogenic protein 15 (BMP15), are highly specific targets for the suppression or elimination of folliculogenesis. These oocyte-specific strategies may offer new, effective alternatives for wildlife contraception

Seven Years of White-Tailed Deer Immunocontraceptive Research at Penn State University: A Comparison of Two Vaccines

PZP and GnRH immunocontraceptive vaccines were each tested in white-tailed deer (Odocoileus virginianus) . Vaccination with PZP produced reversible infertility lasting 1 to 4 years. The first two years of active immunization resulted in an 89% reduction in fawning. Reduction in fawning for the 7-year study containing 4 years of no boosting was 72%. PZP immunization resulted in multi-estrus behavior, with contracepted deer returning to estrus up to 7 times. A five year study of GnRH immunization was conducted in both male and female deer. Treatment of does led to reduced fawning rates, reduced estrus behavior and reduced concentrations of progesterone. During active immunization GnRH does bred to untreated bucks had an 88% reduction in fawning caused by either immunocontraception or immunocontragestion. Reduction in fawning for the 5 year study containing 2 years of no boosting was 74%. The vaccine effect was reversible and directly related to the antibody titer. Infertility lasted up to two years without boosting. GnRH immunized bucks had no interest in sexual activity when paired with control females. Depending on the immunization schedule, antlers either dropped early or remained in velvet

Physiological effects of gonadotropin-releasing hormone immunocontraception on white-tailed deer

Before immunocontraceptives can be considered safe to use on wildlife species, potential health risks should be assessed. Gonadotropin-releasing hormone (GnRH) immunocontraceptive has successfully reduced fertility of white-tailed deer (Odocoileus virginianus); however, associated deer physiology has rarely been examined. We conducted gross necropsy examinations, histology, and blood chemistry comparisons on euthanized deer previously vaccinated with immunogenic GnRH (n = 18 females and n = 4 males), or left as untreated controls (n = 7 females and n = 6 males). Granulomas were found at injection sites of most deer, even 3 years post-treatment. There were no significant differences in ovary (F2,22= 0.31, P = 0.73), or pituitary weights (F2,22 = 0.30, P = 0.75) between treatment groups. Ovaries from control females had significantly more secondary follicles (F2,21 = 20.56, P ≤ 0.001), but not Graafi an follicles (F2,22= 2.22, P = 0.13). Immunized males had significantly lower mean testes weights, a number of morphologic abnormalities, and varying degrees of aspermatogenesis with fewer mature spermatozoa. We do not recommend treating male deer with anti-GnRH immunocontraceptive vaccines

Physiological effects of gonadotropin-releasing hormone immunocontraception on white-tailed deer

Before immunocontraceptives can be considered safe to use on wildlife species, potential health risks should be assessed. Gonadotropin-releasing hormone (GnRH) immunocontraceptive has successfully reduced fertility of white-tailed deer (Odocoileus virginianus); however, associated deer physiology has rarely been examined. We conducted gross necropsy examinations, histology, and blood chemistry comparisons on euthanized deer previously vaccinated with immunogenic GnRH (n = 18 females and n = 4 males), or left as untreated controls (n = 7 females and n = 6 males). Granulomas were found at injection sites of most deer, even 3 years post-treatment. There were no significant differences in ovary (F2,22= 0.31, P = 0.73), or pituitary weights (F2,22 = 0.30, P = 0.75) between treatment groups. Ovaries from control females had significantly more secondary follicles (F2,21 = 20.56, P ≤ 0.001), but not Graafi an follicles (F2,22= 2.22, P = 0.13). Immunized males had significantly lower mean testes weights, a number of morphologic abnormalities, and varying degrees of aspermatogenesis with fewer mature spermatozoa. We do not recommend treating male deer with anti-GnRH immunocontraceptive vaccines

Library Discussion Panel Part I

Interview 1. The Library Interview Series is a set of interviews with a variety of personnel involved with the planning and building of the new Jerry Falwell Library building. The building’s history and planning are discussed as well as the history of the library in general. The recordings were made just before the opening of the new building in early 2014. Lowell Walters; Carl Merat; Abigail Sattler; Greg Smit

Determination of DiazaCon in Quail Feed and Quail Serum by Ion Pair Reversed-Phase Chromatography

Liquid chromatographic (LC) methods were developed for quantitating the potential avian contraceptive DiazaCon in quail feed and serum. DiazaCon was extracted from ground quail feed with basic n-butyl chloride. The n-butyl chloride extract was evaporated to dryness. The DiazaCon residues were dissolved in an aqueous methanolic ion pairing solution and quantitated by LC at 206 nm. Avian sera was combined with an equal volume of a pH 4 aqueous solution of ion pairing reagent and filtered to remove interfering proteins. DiazaCon was quantitated by LC. Mean recoveries for 500 and 2000 ppm fortified feed were 89.1 and 91.0%, respectively. The mean recovery for sera fortified at 5 levels ranging from 35 to 2000 ppm was 84.9%. Method limits of detection were approximately 14 and 13 ppm for feed and sera, respectively