Upgrades and redesign of the National Ignition Facility's soft x-ray opacity spectrometer (OpSpec).

The soft x-ray Opacity Spectrometer (OpSpec) used on the National Ignition Facility (NIF) has recently incorporated an elliptically shaped crystal. The original OpSpec used two convex cylindrical crystals for time-integrated measurements of point-projection spectra from 540 to 2100 eV. However, with the convex geometry, the low-energy portion of the spectrum suffered from high backgrounds due to scattered x-rays as well as reflections from alternate crystal planes. An elliptically shaped crystal allows an acceptance aperture at the crossover focus between the crystal and the detector, which reduces background and eliminates nearly all reflections from alternate crystal planes. The current elliptical design is an improvement from the convex cylindrical design but has a usable energy range from 900 to 2100 eV. In addition, OpSpec is currently used on 18 NIF shots/year, in which both crystals are typically damaged beyond reuse, so efficient production of 36 crystals/year is required. Design efforts to improve the existing system focus on mounting reliability, reducing crystal strain to increase survivability between mounting and shot time, and extending the energy range of the instrument down to 520 eV. The elliptical design, results, and future options are presented.

Implementation of a 1-2 keV point-projection x-ray spectrometer on the National Ignition Facility.

A point-projection soft X-ray Opacity Spectrometer (OpSpec) has been implemented to measure X-ray spectra from ∼1 to 2 keV on the National Ignition Facility (NIF). Measurement of such soft X-rays with open-aperture point-projection detectors is challenging because only very thin filters may be used to shield the detector from the hostile environment. OpSpec diffracts X-rays from 540 to 2100 eV off a potassium (or rubidium) acid phthalate (KAP or RbAP) crystal onto either image plates or, most recently, X-ray films. A "sacrificial front filter" strategy is used to prevent crystal damage, while 2 or 3 rear filters protect the data. Since May 2017, OpSpec has been recording X-ray transmission data for iron-magnesium plasmas on the NIF, at "Anchor 1" plasma conditions (temperature ∼150 eV, density ∼7 × 1021 e -/cm3). Upgrades improved OpSpec's performance on 6 NIF shots in August and December 2017, with reduced backgrounds and 100% data return using filter stacks as thin as 2.9 µm (total). Photometric noise is beginning to meet requirements, and further work will reduce systematic errors.

Structured photocathodes for improved high-energy x-ray efficiency in streak cameras.

We have designed and fabricated a structured streak camera photocathode to provide enhanced efficiency for high energy X-rays (1-12 keV). This gold coated photocathode was tested in a streak camera and compared side by side against a conventional flat thin film photocathode. Results show that the measured electron yield enhancement at energies ranging from 1 to 10 keV scales well with predictions, and that the total enhancement can be more than 3×. The spatial resolution of the streak camera does not show degradation in the structured region. We predict that the temporal resolution of the detector will also not be affected as it is currently dominated by the slit width. This demonstration with Au motivates exploration of comparable enhancements with CsI and may revolutionize X-ray streak camera photocathode design.

Design of the opacity spectrometer for opacity measurements at the National Ignition Facility.

Recent experiments at the Sandia National Laboratory Z facility have called into question models used in calculating opacity, of importance for modeling stellar interiors. An effort is being made to reproduce these results at the National Ignition Facility (NIF). These experiments require a new X-ray opacity spectrometer (OpSpec) spanning 540 eV-2100 eV with a resolving power E/ΔE > 700. The design of the OpSpec is presented. Photometric calculations based on expected opacity data are also presented. First use on NIF is expected in September 2016.

A multi-wavelength, high-contrast contact radiography system for the study of low-density aerogel foams.

A multi-wavelength, high contrast contact radiography system has been developed to characterize density variations in ultra-low density aerogel foams. These foams are used to generate a ramped pressure drive in materials strength experiments at the National Ignition Facility and require precision characterization in order to reduce errors in measurements. The system was used to characterize density variations in carbon and silicon based aerogels to ∼10.3% accuracy with ∼30 µm spatial resolution. The system description, performance, and measurement results collected using a 17.8 mg/cc carbon based JX-6 (C20H30) aerogel are discussed in this manuscript.

High quantum efficiency photocathode simulation for the investigation of novel structured designs.

A computer model in CST Studio Suite has been developed to evaluate several novel geometrically enhanced photocathode designs. This work was aimed at identifying a structure that would increase the total electron yield by a factor of two or greater in the 1-30 keV range. The modeling software was used to simulate the electric field and generate particle tracking for several potential structures. The final photocathode structure has been tailored to meet a set of detector performance requirements, namely, a spatial resolution of <40 µm and a temporal spread of 1-10 ps. We present the details of the geometrically enhanced photocathode model and resulting static field and electron emission characteristics.

A geophysical shock and air blast simulator at the National Ignition Facility.

The energy partitioning energy coupling experiments at the National Ignition Facility (NIF) have been designed to measure simultaneously the coupling of energy from a laser-driven target into both ground shock and air blast overpressure to nearby media. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from the NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of full-scale seismic and air blast phenomena. This report summarizes the development of the platform, the simulations, and calculations that underpin the physics measurements that are being made, and finally the data that were measured. Agreement between the data and simulation of the order of a factor of two to three is seen for air blast quantities such as peak overpressure. Historical underground test data for seismic phenomena measured sensor displacements; we measure the stresses generated in our ground-surrogate medium. We find factors-of-a-few agreement between our measured peak stresses and predictions with modern geophysical computer codes.

Gamma-delta T-cell responses during subcutaneous Mycobacterium avium subspecies paratuberculosis challenge in sensitized or naive calves using matrix biopolymers.

We have developed a model to explore the early immune response against Mycobacterium avium subspecies paratuberculosis (Map) infection in the bovine calf using subcutaneously placed liquid gel matrix biopolymer (matrigel) containing live Map. Matrigel rapidly polymerizes in vivo, retains recruited cellular infiltrates and soluble immune mediators, and can be rapidly removed 48 hours later and depolymerized for analysis. In this study, we examined early host immune events at matrigel/Map sites; recruited cells were evaluated by histopathology and flow cytometry, and cytokines were measured by flow cytometry, enzyme-linked immunosorbent assay, and Luminex bead immunoassay. Our results demonstrate earlier recruitment of gamma-delta (γδ) T cells to matrigel/Map challenge sites compared to CD4+ T cells. We also show that significantly more γδ T cells were recruited to matrigel/Map sites postinfection day 7 compared to postinfection day 30 and that these cells produced significant amounts of the cytokine interferon gamma. We also provide evidence that peripheral blood-derived γδ T-cell subsets in cattle differentially generate interferon gamma, suggesting distinct roles for these cells. These data provide unique insight into initial antimycobacterial host cellular immune responses following Map infection in calves.

Direct inoculation of Mycobacterium avium subspecies Paratuberculosis into ileocecal Peyer's patches results in colonization of the intestine in a calf model.

The objective of this study was to develop an intestinal model of Mycobacterium avium subspecies paratuberculosis (Map) infection in the calf for evaluation of mucosal pathology and local and systemic immunologic responses. Map was inoculated into Peyer's patches of young calves using a right flank surgical approach in standing calves to exteriorize the ileocecal junction. Inoculum doses ranging from 10(3) to 10(9) colony-forming units of strain K10 Map were injected through the serosal surface into Peyer's patches of the distal ileum near the ileocecal valve. Fecal samples were collected for culture from each calf weekly until termination of the study. Calves were necropsied at 7, 30, 60, and 90 days after infection, when inoculation sites, lymph nodes, spleen, and peripheral blood were collected for evaluation. Ileocecal lymph nodes were consistently colonized by Map in the 10(5) to 10(9) groups. The ileocecal valve was also colonized in 10(7) and 10(9) groups. This correlated with fecal culture results as infected calves intermittently shed Map in their feces throughout the study. Granulomatous lesions with giant cells and acid-fast bacilli at the ileocecal junction, ileocecal lymph nodes, and lamina propria of high-dose animals (10(7) and 10(9)) were identified from each time point. Flow cytometry was used to detect antigen-specific production of interferon-γ and interleukin-4 locally (ileocecal lymph node) and systemically (peripheral blood mononuclear cells), which defined distinct immunologic profiles in low-dose and high-dose calves. This study demonstrates intestinal Map infection via Peyer's patch inoculation, a novel model with many shared features of natural Map infection.

Inducible nitric oxide synthase immunoreactivity in the granulomatous intestinal lesions of naturally occurring bovine Johne's disease.

Inducible nitric oxide synthase (iNOS) is important in the control of a number of intracellular pathogens, including mycobacteria, and is a marker of classic macrophage activation. In human granulomatous diseases such as leprosy, a spectrum of granulomatous lesions is described, ranging from the tuberculoid to lepromatous types. Tuberculoid granulomas are associated with enhanced iNOS production and improved clinical outcomes over the lepromatous types. The aim of this study is to determine whether an association exists between morphology of bovine Johne's disease granulomas and lesion macrophage effector functions. To accomplish this, we retrospectively evaluated 24 cases of bovine Johne's disease. In each case, we recorded the predominant granuloma morphology and evaluated iNOS immunoreactivity and bacterial burden by acid-fast stains and mycobacterial immunolabeling. The results of this study demonstrate that all cases had granulomas with features most similar to the lepromatous type. This morphology correlated with heavy bacterial burdens demonstrated by acid-fast staining and mycobacterial immunoreactivity. None of the cases had high expression of iNOS in mycobacterial-positive granulomas. When iNOS immunoreactivity was identified, it was usually located near the crypts and was distinct from the granulomatous foci.

Cellular distribution of anionic antimicrobial peptide in normal lung and during acute pulmonary inflammation.

Anionic peptides (APs) are small antimicrobial peptides present in human and ovine lung. In this study APs were also detected in bovine lung, and production of APs in lungs with acute inflammation induced by various stimuli was determined. The distribution and intensity of APs were determined by immunohistochemistry in lungs of 1) neonatal calves (1-3 days of age) inoculated with Mannheimia (Pasteurella) haemolytica, a known inducer of the bovine beta-defensin lingual antimicrobial peptide (LAP) or pyrogen-free saline (PFS), and 2) growing calves (3 months of age) similarly inoculated with M. haemolytica, a lipopolysaccharide (LPS) from M. haemolytica, an LPS-associated protein from M. haemolytica, or PFS. APs were also detected by western blots with the same antibody in lungs of the calves above, as well as in calves inoculated with Pseudomonas aeruginosa, and an adult cow. Anionic peptide (AP) immunoreactivity was detected in bands (approximate weights) in the western blots of lung at 28-30 (strongest signal), 31, 45, and 52-60 kd regardless of inoculum. The adult cow lacked bands at 45 kd, but it had additional bands at 64 (inconsistently) and 35-38 kd. All these band sizes are consistent with those of the western blots of human and ovine lung. The cellular distribution of APs in lung of neonatal and growing cattle was similar to that in lung of human and sheep. In lungs with acute inflammation induced by live bacteria, LPS, or protein, AP distribution and intensity were similar to those in control (PFS-inoculated) lungs and slightly decreased in bronchioles. This work demonstrates that AP is present in lung of cattle and is thereby conserved among two ruminant species and man. Distribution and intensity of AP production are not enhanced by infection or acute inflammation and are decreased in bronchioles, which suggests that AP is not induced like beta-defensins such as LAP, but, instead, is produced constitutively.

Using simulation and budget models to scale-up nitrogen leaching from field to region in Canada.

Efforts are underway at Agriculture and Agri-Food Canada (AAFC) to develop an integrated, nationally applicable, socioeconomic/biophysical modeling capability in order to predict the environmental impacts of policy and program scenarios. This paper outlines our Decision Support System (DSS), which integrates the IROWCN (Indicator of the Risk of Water Contamination by Nitrogen) index with the agricultural policy model CRAM (Canadian Regional Agricultural Model) and presents an outline of our methodology to provide independent assessments of the IROWCN results through the use of nitrogen (N) simulation models in select, data-rich areas. Three field-level models--DSSAT, N_ABLE, and EPIC--were evaluated using local measured data. The results show that all three dynamic models can be used to simulate biomass, grain yield, and soil N dynamics at the field level; but the accuracy of the models differ, suggesting that models need to be calibrated using local measured data before they are used in Canada. Further simulation of IROWCN in a maize field using N_ABLE showed that soil-mineral N levels are highly affected by the amount of fertilizer N applied and the time of year, meaning that fertilizer and manure N applications and weather data are crucial for improving IROWCN. Methods of scaling-up simulated IROWCN from field-level to soil-landscape polygons and CRAM regions are discussed.

Temporal and morphologic characterization of the distribution of porcine reproductive and respiratory syndrome virus (PRRSV) by in situ hybridization in pigs infected with isolates of PRRSV that differ in virulence.

Three groups of 5-week-old cesarian-derived, colostrum-deprived pigs were inoculated intranasally with either a high-virulence isolate (VR2385) or a low-virulence isolate (VR2431) of porcine reproductive and respiratory syndrome virus (PRRSV) or with uninfected cell culture and media. Formalin-fixed, paraffin-embedded tissues from pigs euthanatized at 10, 21, and 28 days post-inoculation were examined by in situ hybridization for PRRSV nucleic acid using a digoxigenin-labeled antisense RNA probe approximately 1,000 nucleotides in length. Alveolar macrophages were positive in the lungs of 9/9, 2/2, and 0/2 VR2385-inoculated pigs and 7/9, 1/2, and 2/3 VR2431-inoculated pigs at 10, 21, and 28 days post-inoculation, respectively. More positive cells were detected in lungs from VR2385-inoculated pigs compared to VR2431-inoculated pigs at 10 and 21 days post-inoculation. Positive cells within lymph nodes were tingible body macrophages in germinal centers and macrophages or interdigitating dendritic cells within the paracortical area. VR2385 was detected in the tracheobronchial lymph node (TBLN) and mediastinal lymph node (MLN) of 7/9 and 9/9 pigs at 10 days post-inoculation, but was only detected in the TBLN of 1/2 and 0/2 pigs and in the MLN of 0/2 and 1/2 pigs at 21 and 28 days post-inoculation, respectively. In contrast, VR2431 was detected in teh TBLN and MLN of 5/9 and 2/9 pigs at 10 days post-inoculation and in the TBLN of 0/2 and 1/3 pigs and in the MLN of 0/2 and 0/3 pigs at 21 and 28 days post-inoculation, respectively. There were more positive cells in TBLN and MLN in pigs inoculated with VR2385 at 10 days post-inoculation. Macrophages located at the epithelial-lymphoid interface of tonsilar crypts and within the paracortical areas were positive in tonsils of 9/9, 2/2, and 1/2 VR2385-inoculated pigs and 7/9, 1/2, and 1/3 VR2431-inoculated pigs at 10, 21, and 28 days post-inoculation, respectively. Positive cells in the thymic medulla were multinucleate and were only detected at 10 days post-inoculation in 2/9 VR2385-inoculated pigs and 4/9 VR2431-inoculated pigs. Positive cells within the spleen were few, spindle-shaped, located within smooth muscle trabecula, and only present at 10 days post-inoculation in 3/9 VR2385-inoculated pigs. We conclude that the tissue tropism and distribution of positive cells within tissues is similar for VR2385 and VR2431. However, tissues from more pigs and more cells within tissues were positive in pigs inoculated with VR2385 than VR2431 at 10 and 21 days post-inoculation. These findings indicate that the more virulent isolate VR2385 may replicate better in vivo than the less virulent isolate VR2431. This supports the hypothesis that an increased ability to replicate in vivo contributes to increased virulence of PRRSV.

Rebound responding following a single dose of drug using an amphetamine-vehicle-haloperidol drug discrimination.

The purpose of this research was to characterize drug-induced rebound cue states using a three-choice, agonist-vehicle-antagonist drug-discrimination procedure. Rats were trained to discriminate among 0.50 mg/kg amphetamine (AM), distilled water (DW), and 0.03 mg/kg haloperidol (HA) in a three-lever drug discrimination task. Time-dependent changes in cue state were assessed following single doses of AM (5 and 10 mg/kg), HA (1 mg/kg), and cocaine (30 and 40 mg/kg). Consistent with expectations derived from the results of a study that used a two-lever AM-HA discrimination task, single doses of AM produced rebound responding on the HA-appropriate lever that was dose-dependent and peaked at 24 h following administration. In addition, cocaine substituted for AM at 0.5-2 h post-injection and then produced HA-like rebound responding that peaked at 24-36 h post-administration. Contrary to expectations, however, rebound AM-like responding did not occur following HA administration. Perhaps two- and three-choice discrimination tasks differ in their ability to characterize qualitative aspects of the post-haloperidol cue state. Knowledge of the time course of drug-induced adaptive processes, measured as withdrawal in the present research, is necessary for a complete description of a drug's effects and is important in understanding the effects of repeated drug administration.

Evidence suggesting a point source exposure in an outbreak of bovine abortion due to neosporosis.

A Holstein dairy farm suffered an abortion outbreak due to neosporosis. Abortion losses were > 18%. Cows with the highest Neospora antibody titers were at the greatest risk of aborting. Mummified fetuses were found after the 43rd day of the outbreak. The epidemic curve was suggestive of a point source exposure, which is consistent with the hypothesis that Neospora can be spread by a definitive host.

D2-specific discriminative stimuli: parameters, blocking, and rebound.

This study characterizes the cue properties of quinpirole (LY 171555), a selective D2 agonist, and the blocking capabilities of spiperone, a selective D2 antagonist. After rats were trained to discriminate 0.025 mg/kg quinpirole from distilled water, a dose-response curve and time course of the quinpirole discriminative stimulus were determined. The effectiveness of three doses of spiperone in blocking the discriminative stimulus produced by 0.02 mg/kg quinpirole was then assessed. Finally, the time course of spiperone's blocking action was determined. Given the putative selective action of these drugs on D2 receptors and the parametric data presented here, it was predicted that following chronic treatment with spiperone, a rebound increase in quinpirole-appropriate responding would occur. Neither chronic treatment with spiperone nor chronic treatment with haloperidol produced the predicted changes. This result, however, may be confined to the specific dose and time parameters used.

Immunohistochemical identification of porcine reproductive and respiratory syndrome virus (PRRSV) antigen in the heart and lymphoid system of three-week-old colostrum-deprived pigs.

Porcine reproductive and respiratory syndrome virus (PRRSV) antigens were detected by a streptavidin-biotin complex technique in tissues of 3-week-old colostrum-deprived pigs that had been inoculated intranasally with PRRSV and had developed moderate respiratory disease. Moderate, multifocal, tan-colored consolidation of the lungs and severe enlargement of the lymph nodes were noted at necropsy. Severe interstitial pneumonia characterized by type 2 pneumocyte proliferation, septal infiltration with mononuclear cells, and accumulation of macrophages and necrotic cells in alveolar spaces was observed at 4 and 9 days postinoculation. Moderate multifocal perivascular lymphohistiocytic myocarditis was observed at 9 days postinoculation. Marked lymphoid follicular hyperplasia and follicular necrosis in the tonsil, spleen, and lymph nodes was observed. A monoclonal antibody that recognizes a conserved epitope of PRRSV nucleocapsid protein was used as primary antibody for immunohistochemistry. Antigen was readily detected in alveolar macrophages in the lung and in endothelial cells and macrophages in the heart. Macrophages and cells resembling dendritic cells in tonsil, lymph nodes, thymus, and spleen also stained intensely positive for viral antigen. PRRSV appears to replicate primarily within macrophages in the respiratory and lymphoid systems of the pig.

Mucosal and systemic humoral immune response to Bordetella avium in experimentally infected turkeys.

Antibody response to Bordetella avium was measured in serum and mucosal secretions of experimentally infected turkeys. Two-day-old turkeys were inoculated with B. avium, and four inoculated turkeys and four uninoculated control birds per trial were euthanatized weekly from 1 through 8 weeks postinoculation (PI). Maternal antibody of the IgG isotype, present in all 2-day-old birds sampled, decreased to background levels by 3 weeks of age. Antibody (IgG, IgM, IgA) was detected in serum, tracheal washings, and lacrimal secretions in response to B. avium infection. Regardless of the sample site and isotype, antibody levels peaked at 4-6 weeks PI and then decreased rapidly from 6 to 8 weeks PI. In general, IgM and IgA levels peaked earlier (4-5 weeks PI) but declined more rapidly than IgG levels. Numbers of B. avium in the trachea peaked at 2-3 weeks PI and then decreased rapidly from 4 to 8 weeks PI. Even though no direct causal relationship could be determined, the results indicate that an increasing level of antibody in serum, tracheal washings, and lacrimal secretions is temporally associated with clearance of B. avium from the trachea.