1,018 research outputs found
Measurement of Holmium Rydberg series through MOT depletion spectroscopy
We report measurements of the absolute excitation frequencies of Ho
and odd-parity Rydberg series. The states are
detected through depletion of a magneto-optical trap via a two-photon
excitation scheme. Measurements of 162 Rydberg levels in the range
yield quantum defects well described by the Rydberg-Ritz formula. We observe a
strong perturbation in the series around due to an unidentified
interloper at 48515.47(4) cm. From the series convergence, we determine
the first ionization potential cm, which is
three orders of magnitude more accurate than previous work. This work
represents the first time such spectroscopy has been done in Holmium and is an
important step towards using Ho atoms for collective encoding of a quantum
register.Comment: 6 figure
Comparative Gamma Delta T Cell Immunology: A Focus on Mycobacterial Disease in Cattle
A theme among many pathogenic mycobacterial species affecting both humans and animals is a prolonged asymptomatic or latent period that can last years to decades. The mechanisms that favor progression to active disease are not well understood. Pathogen containment is often associated with an effective cell-mediated or T-helper 1 immune profile. With certain pathogenic mycobacteria, such as Mycobacterium avium subspecies paratuberculosis, a shift to active clinical disease is associated with loss of T-helper 1 immunity and development of an ineffective humoral or T-helper 2 immune response. Recently γδ T cells have been shown to play a role early in mycobacterial infections and have been hypothesized to influence disease outcome. The purpose of this paper is to compare recent advancements in our understanding of γδ T cells in humans, cattle, and mice and to discuss roles of γδ T cells in host response to mycobacterial infection
Use Of Micro-Void Content Growth Rates To Validate And Add Value To Electrical Insulation Tan-Delta Aging Testing
Our research as well as others has shown that micro-void content in electric insulation
polymers grows in a way that can be correlated to the degree of aging. Specific results of our
experiments combined with research by others have led us to conclude that a promising technique
for predicting remaining life in electric cable insulation, based on micro-void content and proximity
to void limiting parameters, can be developed.
This approach involves use of acoustic or optical microscopy to establish an estimate of void
content in polymers by determining micro-void sizes and density. Separate research is used to
establish limiting values for percent void content correlating to material failure. The mode of
failure varies depending on the applied voltage regime. For example, at medium and high voltage
levels, partial discharge detection can be considered indicative of pending end of life. Whereas for
low voltage regimes, brittleness to the point of cracking susceptibility would allow the potential for
moisture ingress and shorting and can be considered end of life. It has been separately shown that
void growth rate is a function of temperature and radiation dose rate both during normal and nuclear
accident conditions and is predictable based on the known polymer chemical degradation equations,
which produce gaseous products in the form of oxygen, water vapor, carbon dioxide, and carbon
monoxide.
Thus if end of life void content is known, the degree of void content growth occurring during
a design basis accident is properly accounted for, and void content growth rates during normal
temperature and radiation conditions are considered, then remaining life in electrical insulation can
be accurately predicted. In recent years, several techniques have been proposed to assess electrical
insulation aging. One of the more promising approaches for use with medium voltage cable is the
tan-delta technique. This paper will demonstrate how the mirco-void content approach can be used
to validate other techniques such as tan-delta and add additional meaning and value not otherwise
available from tan-delta alone
Disseminated \u3ci\u3eLeishmania infantum\u3c/i\u3e infection in two sibling foxhounds due to possible vertical transmission
Two sibling foxhounds born to a Leishmania seropositive bitch were presented after testing seropositive for Leishmania. Leishmania infantum infection was detected via histopathology, culture, and quantitative polymerase chain reaction (q-PCR). This is the first report of natural infection with Leishmania infantum with the possibility for vertical transmission in North America.
Infection disséminée à Leishmania infantum chez deux chiots Fox hound d’une même portée reliée possiblement à une transmission verticale. Deux chiots Fox hound d’une même portée nés d’une mère séropositive à Leishmania ont été présentés après un contrôle sérologique positif. Une infection à Leishmania infantum a été détectée par histopathologie, culture et amplification en chaîne par polymérase quantitative (ACP-q). Il s’agit du premier rapport d’infection naturelle par Leishmania infantum possiblement relié à une transmission verticale en Amérique du Nord
Effect of dietary protein on the renin-angiotensin system in subtotally nephrectomized rats
Effect of dietary protein on the renin-angiotensin system in subtotally nephrectomized rats. Dietary protein restriction improves the course of renal disease in the remnant kidney model. Dietary protein restriction can also reduce plasma renin activity in several circumstances. We examined the interaction between dietary protein and the renin-angiotensin system in subtotally nephrectomized rats (1-2/3 nephrectomy). No difference was seen in tissue renin activity in rats ingesting a high (30%) versus a low (6%) protein diet. To determine the pathophysiological role of angiotensin II in subtotally nephrectomized rats, we examined the acute renal response to an intrarenal infusion of the angiotensin II antagonist Sar1 Gly8-angiotensin II (10 µg/kg/min). Only those subtotally nephrectomized animals ingesting a high protein diet exhibited a consistent improvement in glomerular permselectivity, as manifested by a 24% fall in the fractional clearance of albumin (basal 16.19 ± 3.65 × 10-4 vs. Sar1 Gly8-AII 12.26 ± 3.21 × 10-4; P < 0.02) and a 19% fall in the fractional clearance of IgG (basal 3.75 ± 0.67 × 10-4 vs. Sar1 Gly8-AII 3.03 ± 0.48 × 10-4; P < 0.02). No consistent change occurred in glomerular permselectivity in the rats on the low protein diet or rats infused with vehicle only. No change in mean arterial pressure or whole-kidney hemodynamics were seen with angiotensin II blockade. Decrements in SNGFR and glomerular capillary pressure occurred with angiotensin blockade in the animals ingesting the high protein diet, suggesting hemodynamic factors as a mechanism for the improvement in permselective defects. In conclusion, dietary protein intake determines the glomerular response to angiotensin II blockade, implicating local angiotensin II as an injurious factor with high protein feeding in subtotally nephrectomized rats
Comparison of Sheep, Goats, and Calves as Infection Models for Mycobacterium avium subsp. paratuberculosis
Animal infection models to study Mycobacterium avium subsp. paratuberculosis (MAP) infection are useful for evaluating the efficacy of vaccines and other therapeutics for the prevention or treatment of infection. The goal of the present study was to compare smaller ruminants, sheep and goats, with calves as infection models. Neonatal sheep, goats, and calves (n = 4) received 109 cfu of a cattle isolate of MAP in milk replacer on days 0, 3 and 6 in a 12-month study and sampled monthly thereafter. Results demonstrated a robust antigen-specific IFN-γ response at 90 days post-inoculation for sheep and goats, with lower responses noted for calves. By 360 days, IFN-γ responses were 50 and 82% higher for calves than for goats and sheep, respectively. Although MAP- specific antibody responses were first observed in sheep at 90 days, calves had higher antibody responses throughout the remainder of the study. Following pass-through shedding on day 7, fecal shedding was fairly negligible across treatments but remained higher for calves throughout the study. Colonization of tissues was variable within treatment group and was higher for calves and sheep for the majority of tissues. Upon antigen stimulation of PBMCs, higher populations of CD4 + T cells cells and lower populations of γδ TCR + and NK cells were observed for goats and calves compared to sheep. Relative gene expression of IL-4, IL-12, and IL-17 in PBMCs was higher in goats, corresponding to lower tissue colonization with MAP. These data suggest that ruminant species are fairly comparable as infection models for MAP, but discrete differences in host responses to MAP infection exist between species
- …