Inertial Weldment of Rhenium and Inconel 718

Inertia welding has been found to be a successful method for joining pure rhenium to Inconel 718, and with additional experimentation, this process may have great potential for rocket nozzle applications. Refractory metals are ideally suited to this application, where high temperatures and oxidizing environment survivability is required, but not all of the thruster must be made of these materials, only the areas that require them. A bolted joint between the two metals is not ideal, especially for small thrusters where the mess of a bolted join will come at a steep price. A welded joint would be preferred for flight thrusters

Prevention of Mycobacterium avium Subspecies paratuberculosis (MAP) Infection in Balb/c mice by Feeding Lactobacillus acidophilus Strain NP-51®

The immune responses of 390 BALB/c mice fed the probiotic Lactobacillus acidophilus strain NP51 ® and infected with Mycobacterium avium subspecies paratuberculosis (MAP) were evaluated in a 6-month trial. Mice were randomized to nine treatment groups that fed either viable- or heat-killed NP51 and inoculated with either viable- or heatkilled MAP or sterile phosphate-buffered saline. Feeding the NP51 resulted in higher numbers of T lymphocytes in the spleen including the CD8 + cytotoxic T lymphocytes. In addition, feeding the NP51 lowered the number of immune suppressive T regulatory cells CD4 + CD25 + and CD8 + CD25 + cells in the spleen. Additionally, feeding the NP51 resulted in higher concentration of interferon-gamma in the supernatant of splenocytes cultured in vitro. These results suggest that feeding the NP51 to BALB/c mice might prevent the progression of MAP infection in mice

Therapeutic use of a receptor mimic probiotic reduces intestinal Shiga toxin levels in a piglet model of hemolytic uremic syndrome

BACKGROUND: Hemolytic uremic syndrome (HUS) is a systemic and potentially fatal complication of gastroenteritis secondary to Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) infection characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal damage. Shiga toxin (Stx), the toxin principle in HUS, is produced locally within the gut following EHEC colonization and is disseminated via the vasculature. Clinical development of HUS currently has no effective treatment and is a leading cause of renal failure in children. Novel post-exposure therapies are currently needed for HUS; therefore, the purpose of this study was to investigate the efficacy of a Stx receptor mimic probiotic in a porcine model of HUS. Edema disease, an infection of swine caused by host adapted Shiga toxin-producing Escherichia coli (STEC) and mediated by Shiga toxin 2e (Stx2e), shares many pathogenic similarities to HUS. In this study, three-week old piglets were inoculated with STEC and 24 hours later treated twice daily with a probiotic expressing an oligosaccharide receptor mimic for Stx2e to determine if the probiotic could reduce intestinal toxin levels. METHODS: Piglets were orally inoculated with 10(10) CFU of STEC strain S1191 eight days after weaning. Beginning day 1 post-inoculation, piglets were treated orally twice daily with 5 × 10(11) CFU of either the receptor mimic probiotic or a sham probiotic for 10 days. Intestinal Stx2e levels were assessed daily via Vero cell assay. The efficacy of the probiotic at reducing intestinal Stx2e, vascular lesions, and clinical disease was evaluated with repeated measures ANOVA and Fisher's exact test as appropriate. RESULTS: The probiotic significantly reduced intestinal Stx2e, as reflected by decreased fecal toxin titers on days 3-8 post-inoculation (p < 0.01). Despite this reduction in intestinal toxin levels, however, the probiotic failed to reduce the incidence of vascular necrosis in target organs and had no effect on clinical disease. CONCLUSIONS: The data suggest that post-exposure treatment with a Stx-binding probiotic is effective in reducing intestinal toxin burden. Future studies could target this approach for possible development of post-exposure interventions.Shannon J Hostetter, Amy F Helgerson, James C Paton, Adrienne W Paton, and Nancy A Cornic

Temporal Dynamics of Chronic Inflammation on the Cecal Microbiota in IL-10-/- Mice

The intestinal microbiota is a critical component of mucosal health as evidenced by the fact that alterations in the taxonomic composition of the gastrointestinal microbiota are associated with inflammatory bowel diseases. To better understand how the progression of inflammation impacts the composition of the gastrointestinal microbiota, we used culture independent taxonomic profiling to identify temporal changes in the cecal microbiota of C3Bir IL-10-/- mice concomitantly with the onset and progression of colitis. This analysis revealed that IL-10-/- mice displayed a biphasic progression in disease severity, as evidenced by histopathological scores and cytokine production. Beginning at 4 weeks of age, pro-inflammatory cytokines including TNF-a, IFN-g, IL-6, G- CSF, and IL-1a as well as chemokines including RANTES and MIP-1a were elevated in the serum of IL-10-/- mice. By 19 weeks of age, the mice developed clinical signs of disease as evidenced by weight loss, which was accompanied by a significant increase in serum levels of KC and IL-17. While the overall diversity of the microbiota of both wild type and IL-10-/- were similar in young mice, the latter failed to increase in complexity as the mice matured and experienced changes in abundance of specific bacterial taxa that are associated with inflammatory bowel disease in humans. Collectively, these results reveal that there is a critical time in young mice between four to six weeks of age when inflammation and the associated immune responses adversely affect maturation of the microbiota

VUV frequency combs from below-threshold harmonics

Recent demonstrations of high-harmonic generation (HHG) at very high repetition frequencies (~100 MHz) may allow for the revolutionary transfer of frequency combs to the vacuum ultraviolet (VUV). This advance necessitates unifying optical frequency comb technology with strong-field atomic physics. While strong-field studies of HHG have often focused on above-threshold harmonic generation (photon energy above the ionization potential), for VUV frequency combs an understanding of below-threshold harmonic orders and their generation process is crucial. Here we present a new and quantitative study of the harmonics 7-13 generated below and near the ionization threshold in xenon gas. We show multiple generation pathways for these harmonics that are manifested as on-axis interference in the harmonic yield. This discovery provides a new understanding of the strong-field, below-threshold dynamics under the influence of an atomic potential and allows us to quantitatively assess the achievable coherence of a VUV frequency comb generated through below threshold harmonics. We find that under reasonable experimental conditions temporal coherence is maintained. As evidence we present the first explicit VUV frequency comb structure beyond the 3rd harmonic.Comment: 16 pages, 4 figures, 1 tabl

Safety Evaluation of Lasalocid Use in Chinese Ring-Necked Pheasants (Phasianus colchicus)

Coccidiosis remains a significant threat to the welfare of game farm–reared pheasants in the United States. Although lasalocid has been demonstrated to be effective against pheasant specific coccidia, information regarding its safety in this species is lacking. The purpose of this study was to gather data on the safety of lasalocid when fed to Chinese ring-necked pheasants at one, two, and three times the recommended high dose of lasalocid used for prevention of coccidiosis in other poultry at three times the normal treatment period. Pheasant chicks (approximately 1 day-old; n  =  160) were randomly blocked by sex into four treatment groups and given their respective diets continuously for 6 wk. No significant differences were observed in overall feed consumption, weight gain, feed conversion rates, clinical pathology measurements, or tissue gross and histopathologic evaluations between controls and treatment groups associated with lasalocid administration. Based on the results of this study it appears that lasalocid fed at the recommended rate of 125 ppm is safe in Chinese ring-necked pheasants

Pavement Markings and Delineation for Older Drives. Volume I: Final Report

DTFH61-90-R-00062The objectives of this project were: (1) to identify the needs of older drivers and to evaluate the situations in which older driver performance might be improved through enhanced pavement markings and delineation; (2) to identify the range of potentially useful enhanced treatments; (3) to determine the effectiveness of those treatments judged to be most useful for the older driver; and (4) to assess the costs and benefits of the treatment shown to be most effective. Following a literature review to identify older driver deficiencies, 25 delineation/pavement marking treatments (including several "control" treatments) were identified for testing. A laboratory simulator study was used as a means to determine the most effective among the group. The treatments shown to produce better recognition distance, along with several control treatments, were then subjected to field testing. The field tests were conducted on a closed test track facility, and recognition distance and visual occlusion time were used as dependent measures. Of the 66 subjects who participated in the field study, half were over 65 years of age and half were 45 years of age or less. All subjects were involved in both types of measures. Following the field test performance assessment, the treatments were subjected to a cost benefit analysis and recommendations were made regarding the treatments that could benefit older drivers

Determination of Driver Needs in Work Zones

DOT-FH-11-9549The objectives of the study were: (a) to determine what information drivers need to travel through work zones safely and efficiently; (b) to determine how this information can best be conveyed to the drivers; and (c) to determine where improvements to the present system of work zone traffic control are needed. The study began with an analysis of driver tasks for eight major work zone types: lane closure, shoulder closure, roadside, lane diversion, crossover, temporary detour, detour to alternate routes, and reduced lane width. From this effort, a set of information content needs was identified for each work zone type. A further analytic effort using the principles of the Positive Guidance Procedure and the concept of Decision Sight Distance, resulted in the identification of recommended information presentation locations for the various types of information. These analytic efforts were combined into information requirements which were then evaluated for applicability by exercising each on a series of actual work zones. The requirements were modified where necessary and were then used as the basis for the development of a procedure for the derivation of work zones signing plans. Another aspect of the project involved the evaluation of individual construction-related signs, in which each device was evaluated with respect to several criteria and problems were identified