2,583 research outputs found
Arthritis Is Developed in Borrelia-Primed And -Infected Mice Deficient of Interleukin-17
Interleukin-17 (IL-17) has been shown to participate in the development of Lyme arthritis in experimental mice. For example, neutralization of IL-17 with antibodies inhibits induction of arthritis in Borrelia-primed and -infected C57BL/6 wild-type mice. We hypothesized that mice lacking IL-17 would fail to develop Borrelia-induced arthritis. IL-17-deficient and wild-type C57BL/6 mice were primed with heat-inactivated Borrelia and then infected with viable spirochetes 3 weeks later. No swelling or major histopathological changes of the hind paws were detected in IL-17-deficient or wild-type mice that were primed with Borrelia or infected with viable spirochetes. By contrast, IL-17-deficient and wild-type mice that were primed and subsequently infected with heterologous Borrelia developed severe swelling and histopathological changes of the hind paws. In addition, Borrelia-primed and -infected IL-17-deficient mice exhibited elevated gamma-interferon (IFN-γ) levels in sera and increased frequencies of IFN-γ-expressing lymphocytes in popliteal lymph nodes compared to Borrelia-primed and -infected wild-type mice. These results demonstrate that IL-17 is not required for development of severe pathology in response to infection with Borrelia burgdorferi, but may contribute to disease through an interaction with IFN-γ
Wear and Friction Modeling on Lifeboat Launch Systems
The RNLI provides search and rescue cover along the UK and RoI coast using a variety of lifeboats
and launch techniques. In locations where there is no natural harbour it is necessary to use a slipway
to launch the lifeboat into the sea. Lifeboat slipway stations consist of an initial section where the
boat is held on rollers followed by an inclined keelway lined with low friction composite materials,
the lifeboat is released from the top of the slipway and proceeds under its own weight into the water.
The lifeboat is later recovered using a winch line. It is common to manually apply grease to the
composite slipway lining before each launch and recovery in order to ensure sufficiently low friction
for successful operation. With the introduction of the Tamar class lifeboat it is necessary to upgrade
existing boathouses and standardise slipway operational procedures to ensure consistent operation.
The higher contact pressures associated with the new lifeboat have led to issues of high friction and
wear on the composite slipway linings and the manual application of grease to reduce friction is to be
restricted due to environmental impact and cost factors. This paper presents a multidisciplinary
approach to modelling slipway panel wear and friction using tribometer testing in conjunction with
finite element analysis and slipway condition surveys to incorporate common real-world effects such
as panel misalignments. Finally, it is shown that a freshwater lubrication system is effective,
reducing cost and environmental impacts while maintaining good friction and wear performance
HST Fine Guidance Sensor Astrometric Parallaxes for Three Dwarf Novae: SS Aurigae, SS Cygni, and U Geminorum
We report astrometric parallaxes for three well known dwarf novae obtained
using the Fine Guidance Sensors on the Hubble Space Telescope. We found a
parallax for SS Aurigae of Pi = 5.00 +/- 0.64 mas, for SS Cygni we found Pi =
6.02 +/- 0.46 mas, and for U Geminorum we obtained Pi = 10.37 +/- 0.50 mas.
These represent the first true trigonometric parallaxes of any dwarf novae. We
briefly compare these results with previous distance estimates. This program
demonstrates that with a very modest amount of HST observing time, the Fine
Guidance Sensors can deliver parallaxes of unrivaled precision.Comment: 15 pages, 2 Table
Quantification of hepatic steatosis with 3-T MR imaging: Validation in ob/ob mice
Purpose: To validate quantitative imaging techniques used to detect and measure steatosis with magnetic resonance (MR) imaging in an ob/ob mouse model of hepatic steatosis. Materials and Methods: The internal research animal and resource center approved this study. Twenty-eight male ob/ob mice in progressively increasing age groups underwent imaging and were subsequently sacrificed. Six ob /+ mice served as control animals. Fat fraction imaging was performed with a chemical shift-based water-fat separation method. The following three methods of conventional fat quantification were compared with imaging: lipid extraction and qualitative and quantitative histologic analysis. Fat fraction images were reconstructed with single- and multiple-peak spectral models of fat and with and without correction for T2* effects. Fat fraction measurements obtained with the different reconstruction methods were compared with the three methods of fat quantification, and linear regression analysis and two-sided and two-sample t tests were performed. Results:Lipid extraction and qualitative and quantitative histologic analysis were highly correlated with the results of fat fraction imaging (r2 = 0.92, 0.87, 0.82, respectively). No significant differences were found between imaging measurements and lipid extraction (P = .06) or quantitative histologic (P = .07) measurements when multiple peaks of fat and T2* correction were included in image reconstruction. Reconstructions in which T2* correction, accurate spectral modeling, or both were excluded yielded lower agreement when compared with the results yielded by other techniques. Imaging measurements correlated particularly well with histologic grades in mice with low fat fractions (intercept, -1.0% ± 1.2 [standard deviation ]). Conclusion: MR imaging can be used to accurately quantify fat in vivo in an animal model of hepatic steatosis and may serve as a quantitative biomarker of hepatic steatosis. © RSNA, 2010
Fluctuating Nematic Elastomer Membranes: a New Universality Class
We study the flat phase of nematic elastomer membranes with rotational
symmetry spontaneously broken by in-plane nematic order. Such state is
characterized by a vanishing elastic modulus for simple shear and soft
transverse phonons. At harmonic level, in-plane orientational (nematic) order
is stable to thermal fluctuations, that lead to short-range in-plane
translational (phonon) correlations. To treat thermal fluctuations and relevant
elastic nonlinearities, we introduce two generalizations of two-dimensional
membranes in a three dimensional space to arbitrary D-dimensional membranes
embedded in a d-dimensional space, and analyze their anomalous elasticities in
an expansion about D=4. We find a new stable fixed point, that controls
long-scale properties of nematic elastomer membranes. It is characterized by
singular in-plane elastic moduli that vanish as a power-law eta_lambda=4-D of a
relevant inverse length scale (e.g., wavevector) and a finite bending rigidity.
Our predictions are asymptotically exact near 4 dimensions.Comment: 18 pages, 4 eps figures. submitted to PR
Automated Control Systems and Methods for Underground Crop Harvesters
Methods and devices for automated adjustment of a digging implement during harvest of underground crops are described. Utilizing the devices, a digging implement, e.g., a blade, can be located and maintained at a desired depth as a harvester travels across a field. During use, the digging implement depth controls can be varied as the harvester travels within a single field under different operating conditions, e.g., different soil friability, consistency, etc., thereby preventing crop loss and improving crop yield
Sensitivity and specificity of the ECAS in Parkinson’s disease and Progressive Supranuclear Palsy
Disentangling Parkinson’s disease (PD) and progressive supranuclear palsy (PSP) may be a diagnostic challenge. Cognitive signs may be useful, but existing screens are often insufficiently sensitive or unsuitable for assessing people with motor disorders. We investigated whether the newly developed ECAS, designed to be used with people with even severe motor disability, was sensitive to the cognitive impairment seen in PD and PSP and able to distinguish between these two disorders. Thirty patients with PD, 11 patients with PSP, and 40 healthy controls were assessed using the ECAS, as well as an extensive neuropsychological assessment. The ECAS detected cognitive impairment in 30% of the PD patients, all of whom fulfilled the diagnostic criteria for mild cognitive impairment. The ECAS was also able to detect cognitive impairment in PSP patients, with 81.8% of patients performing in the impaired range. The ECAS total score distinguished between the patients with PSP and healthy controls with high sensitivity (91.0) and specificity (86.8). Importantly, the ECAS was also able to distinguish between the two syndromes, with the measures of verbal fluency offering high sensitivity (82.0) and specificity (80.0). In sum, the ECAS is a quick, simple, and inexpensive test that can be used to support the differential diagnosis of PSP
Tumor necrosis factor alpha, citrullination, and peptidylarginine deiminase 4 in lung and joint inflammation
BACKGROUND: The relationship between lung and joint inflammation in rheumatoid arthritis is poorly understood. Lung inflammation with resultant protein citrullination may trigger anti-citrullinated protein antibodies, inflammation, and arthritis. Alternatively, lung and joint inflammation may be two manifestations of a single underlying pathology. The lung has increased citrullination and TNF-alpha levels are high in rheumatoid arthritis; however, it is unknown if TNF-alpha can induce lung protein citrullination. The citrullinating enzyme peptidylarginine deiminase 4 (PAD4) exacerbates TNF-alpha-induced arthritis, but a role for PAD4 in lung citrullination and TNF-alpha-induced lung inflammation has not been explored. Our aim was to use TNF-alpha-overexpressing mice to clarify the intersection of TNF-alpha, citrullination, PAD4, arthritis, and lung inflammation.
METHODS: Lung protein citrullination in wild-type mice, mice that overexpress TNF-alpha systemically (TNF(+)), TNF(+)PAD4(+/+), and TNF(+)PAD4(-/-) mice was quantified by both gel electrophoresis using a citrulline probe and western blot. Hematoxylin and eosin (HandE)-stained lung sections from TNF(+)PAD4(+/+) and TNF(+)PAD4(-/-) mice were scored for lung inflammation. HandE-stained ankle joint sections from mice that overexpress TNF-alpha only in the lungs were assessed for arthritis.
RESULTS: TNF(+) mice have increased lung protein citrullination. TNF(+)PAD4(-/-) mice do not have significantly reduced lung protein citrullination, but do have decreased lung inflammation compared to TNF(+)PAD4(+/+) mice. Mice that overexpress TNF-alpha only in the lungs do not develop arthritis.
CONCLUSIONS: PAD4 exacerbates lung inflammation downstream of TNF-alpha without having a major role in generalized protein citrullination in inflamed lungs. Also, TNF-alpha-induced lung inflammation is not sufficient to drive murine arthritis
Lifetime determination of excited states in Cd-106
Two separate experiments using the Differential Decay Curve Method have been performed to extract mean lifetimes of excited states in 106 Cd. The inedium-spin states of interest were populated by the Mo-98(C-12, 4n) Cd-106 reaction performed at the Wright Nuclear Structure Lab., Yale University. From this experiment, two isomeric state mean lifetimes have been deduced. The low-lying states were populated by the Mo-96(C-13, 3n)Cd-106 reaction performed at the Institut fur Kernphysik, Universitat zu Koln. The mean lifetime of the I-pi = 2(1)(+) state was deduced, tentatively, as 16.4(9) ps. This value differs from the previously accepted literature value from Coulomb excitation of 10.43(9) ps
CV evolution: AM Her binaries and the period gap
AM Her variables -- synchronised magnetic cataclysmic variables (CVs) --
exhibit a different period distribution from other CVs across the period gap.
We show that non-AM Her systems may infiltrate the longer-period end of the
period gap if they are metal-deficient, but that the position and width of the
gap in orbital period is otherwise insensitive to other binary parameters
(excepting the normalisation of the braking rate). In AM Her binaries, magnetic
braking is reduced as the wind from the secondary star may be trapped within
the magnetosphere of the white dwarf primary. This reduced braking fills the
period gap from its short-period end as the dipole magnetic moment of the white
dwarf increases. The consistency of these models with the observed distribution
of CVs, both AM Her and non-AM Her type, provides compelling evidence
supporting magnetic braking as the agent of angular momentum loss among
long-period CVs, and its disruption as the explanation of the 2 - 3 hour period
gap among nonmagnetic CVs.Comment: 10 pages, 11 figures, to be published in MNRA
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