589 research outputs found
A compilation, tabulation and analysis of spelling errors in grade six
Thesis (Ed.M.)--Boston Universit
Immunization with DNA vaccines in early life: Advantages and limitations as compared to conventional vaccines
Conclusion: DNA vaccines favorably compare to conventional vaccines in their unique capacity to induce, in murine models, adult-like antibody, Th1 and CTL responses at a time of yet significant immune immaturity. Immune responses to DNA vaccines are, however, significantly slower than the one induced by adjuvanted subunit or live vaccines. Although they persist for life in mice, preliminary data in non-human adult primates suggest that this could not be the case in higher mammals. The issue of potential tolerance induction will likely not emerge as a critical feature of human neonatal DNA immunization. However, DNA vaccines are unlikely to prove superior to conventional vaccines in their capacity to circumvent the inhibitory influence of maternal antibodies. Thus, the greater perspectives for neonatal DNA immunization could be found in models where the induction of Th1 and CTL responses are of utmost importance. These are essentially infections with intracellular agents responsible for severe/persistent infections upon early exposure and for which no current efficient and safe conventional vaccine exists. Evaluating neonatal DNA immunization strategies against RSV or herpes viruses, tuberculosis or Chlamydiae therefore emerge as sound prioritie
Single shot ultrafast all optical magnetization switching of ferromagnetic Co/Pt multilayers
In a number of recent experiments, it has been shown that femtosecond laser
pulses can control magnetization on picosecond timescales, which is at least an
order of magnitude faster compared to conventional magnetization dynamics.
Among these demonstrations, one material system (GdFeCo ferromagnetic films) is
particularly interesting, as deterministic toggle-switching of the magnetic
order has been achieved without the need of any symmetry breaking magnetic
field. This phenomenon is often referred to as all optical switching (AOS).
However, so far, GdFeCo remains the only material system where such
deterministic switching has been observed. When extended to ferromagnetic
systems, which are of greater interest in many technological applications, only
a partial effect can be achieved, which in turn requires repeated laser pulses
for full switching. However, such repeated pulsing is not only energy hungry,
it also negates the speed advantage of AOS. Motivated by this problem, we have
developed a general method for single-shot, picosecond timescale, complete all
optical switching of ferromagnetic materials. We demonstrate that in
exchange-coupled layers of Co/Pt and GdFeCo, single shot, switching of the
ferromagnetic Co/Pt layer is achieved within 7 picoseconds after irradiation by
a femtosecond laser pulse. We believe that this approach will greatly expand
the range of materials and applications for ultrafast magnetic switching.Comment: 11 pages, 3 figures, supplementary material
COMPARISON OF THE IMMUNE RESPONSIVENESS OF NZB AND NZB x NZW F1 HYBRID MICE WITH THAT OF OTHER STRAINS OF MICE
The immune responsiveness of (NZB x NZW) F1 hybrid mice (NZB/W) has been compared with that of three other strains of mice, A/J, BALB/c, and CBA/J. The antigens used included sheep red blood cells (SRBC), keyhole limpet hemocyanin (KLH), bovine serum albumin (BSA), and human γ-globulin (HGG). It was found that important strain differences existed in the amount of antibody produced, but the relative immune responsiveness depended very much upon the nature of antigen. By comparison with the other strains tested, NZB/W mice had a higher antibody production to some antigens (SRBC and BSA) but were low responders to others (KLH). Induction of unresponsiveness to HGG by treatment with ultracentrifuged HGG was studied in the strains cited above. NZB/W mice became tolerant after injection of HGG ultracentrifuged at 100,000 g for 2 hr. Similar experiments carried out with another preparation of HGG (centrifuged at 20,000 g for 30 min) failed to reveal any abnormal behavior of NZB/W mice as compared to BALB/c or A/J mice. These results do not support the concept that NZB/W mice possess a general immune hyperreactivity or a relative inability to be made tolerant to protein antigens. However, they do not rule out the possibility that these mice have a genetically determined hyperresponsiveness to some antigens, in particular to nuclear antigens
Structure of the nucleus of 1928+738
Modeling of the trajectories of VLBI components ejected by the nucleus of
1928+738 shows the VLBI jet contains three families of trajectories, i.e. VLBI
components are ejected from three different origins. The fit of components C1,
C6 and C8 indicates that the nucleus of 1928+738 contains two binary black hole
systems. The first binary black hole system is associated with the stationary
components Cg and CS and is characterized by a radius
mas; both black holes ejected VLBI components quasi regularly between 1990 and
2010. The second binary black hole system is not associated with stationary
components and is characterized by a radius mas; it
ejected only three VLBI components between 1994 and 1999. The two black hole
sytems are separated by mas. We briefly discuss the consequences
of the existence of binary black holes systems in radio quasars to make the
link between radio quasars and GAIA.Comment: 18 pages, 24 figures, submitted to Astronomy & Astrophysics. arXiv
admin note: text overlap with arXiv:1307.370
Complement-Mediated Opsonic Activity in Normal and Infected Human Cerebrospinal Fluid: Early Response During Bacterial Meningitis
A local defense mechanism in bacterial meningitis was evaluated in humans by measuring complement-mediated opsonic activity (CMOA) in normal and infected cerebrospinal fluid (CSF) with a complement-dependent phagocytic bactericidal assay. CMOA was absent in normal untreated CSF and remained undetectable in 20 samples of CSF from patients with viral meningitis and five samples from patients with acute meningococcemia. In contrast, 15 of 27 samples of CSF from patients with acute bacterial meningitis had a measurable CMOA, which was correlated with protein concentrations (P < 0.01) and C4 hemolytic activity (P < 0.001) in the CSF. A favorable outcome of bacterial meningitis was associated with the presence of CMOA in CSF (P < 0.005). Recovery was also correlated with higher levels of C4 (P < 0.01) and C3 (P < 0.05) in CSF and with lower concentrations of microorganisms in the sample of CSF collected at the time of admission (P < 0.01). Thus, CMOA, although absent in normal CSF, can appear in CSF during acute bacterial meningitis, particularly in patients who recover completel
- …