1,945 research outputs found
The centrosome and spindle as a ribonucleoprotein complex
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Chromosome Research 19 (2011): 367-376, doi:10.1007/s10577-011-9186-7.The presence of nucleic acids in centrosomes and the spindle have been proposed,
observed, and reported since the 1950s. Why did the subject remain, perhaps even until
today, such a controversial issue? The explanation is manifold, and includes legitimate
concern over contamination from other cellular compartments in biochemical
preparations. With a typically high background of cytoplasmic ribosomes, even
microscopic images of stained intact cells could be difficult to interpret. Also, evidence
for RNA and DNA in centrosomes accumulated for approximately 40 years but was
interspersed with contradictory studies, primarily regarding the presence of DNA
(reviewed in Johnson and Rosenbaum, 1991; Marshall and Rosenbaum, 2000). Perhaps
less tangible but still a likely cause for lingering controversy is that the presence of
nucleic acids in the spindle or centrosomes will require us to look differently at these
structures from a functional, and more to the point, evolutionary standpoint.This work was supported by grants from the NIH (GM088503) and NSF (MCB0843092)
to MCA
A phase I trial to assess the pharmacology of the new oestrogen receptor antagonist fulvestrant on the endometrium in healthy postmenopausal volunteers
While tamoxifen use is associated with clear benefits in the treatment of hormone-sensitive breast cancer, it also exhibits partial oestrogen agonist activity that is associated with adverse events, including endometrial cancer. Fulvestrant (‘Faslodex’) is a new oestrogen receptor antagonist that downregulates the oestrogen receptor and has no known agonist effect. This single-centre, double-blind, randomised, parallel-group trial was conducted to determine the direct effects of fulvestrant on the female endometrium when given alone and in combination with the oestrogen, ethinyloestradiol. Following a 14-day, pretrial screening period, 30 eligible postmenopausal volunteers were randomised to receive fulvestrant 250 mg, fulvestrant 125 mg or matched placebo administered as a single intramuscular injection. Two weeks postinjection, volunteers received 2-weeks concurrent exposure to ethinyloestradiol 20 μg day−1. Endometrial thickness was measured before and after the 14-day screening period with further measurements predose (to confirm a return to baseline) and on days 14, 28 and 42 post-treatment with fulvestrant. Pharmacokinetic and safety assessments were performed throughout the trial. Fulvestrant at a dose of 250 mg significantly (P=0.0001) inhibited the oestrogen-stimulated thickening of the endometrium compared with placebo. Neither the 125 mg nor 250 mg doses of fulvestrant demonstrated oestrogenic effects on the endometrium over the initial 14-day assessment period. Fulvestrant was well tolerated and reduced the incidence of ethinyloestradiol-related side effects. At the same dose level that is being evaluated in clinical trials of postmenopausal women with advanced breast cancer, fulvestrant (250 mg) is an antioestrogen with no evidence of agonist activity in the endometrium of healthy postmenopausal women
A Modified Coupled Enzyme Method for O-linked GlcNAc Transferase Activity Assay
In order to determine the activity of O-linked GlcNAc transferase (OGT), a modified coupled enzyme method was proposed. This method was based on the measurement of uridine 5'-(trihydrogen diphosphate) (UDP), a product generated in transglycosylation reaction. In the assay, UDP was coupled to the conversion of phosphoenolpyruvate to pyruvate using pyruvate kinase. Using a commercial pyruvate assay kit, the pyruvate was converted to a red terminal product, which could be photometrically measured at 570 nm or fluorometrically measured at 587 nm (Em = 535 nm) on a microplate reader. Kinetic study of a truncated recombinant mOGT and quantitative analysis of OGT in two biological samples indicated that this method was practical and competitive for quantitative analysis of OGT
CMB Telescopes and Optical Systems
The cosmic microwave background radiation (CMB) is now firmly established as
a fundamental and essential probe of the geometry, constituents, and birth of
the Universe. The CMB is a potent observable because it can be measured with
precision and accuracy. Just as importantly, theoretical models of the Universe
can predict the characteristics of the CMB to high accuracy, and those
predictions can be directly compared to observations. There are multiple
aspects associated with making a precise measurement. In this review, we focus
on optical components for the instrumentation used to measure the CMB
polarization and temperature anisotropy. We begin with an overview of general
considerations for CMB observations and discuss common concepts used in the
community. We next consider a variety of alternatives available for a designer
of a CMB telescope. Our discussion is guided by the ground and balloon-based
instruments that have been implemented over the years. In the same vein, we
compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the
South Pole Telescope (SPT). CMB interferometers are presented briefly. We
conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and
Planck, to demonstrate a remarkable evolution in design, sensitivity,
resolution, and complexity over the past thirty years.Comment: To appear in: Planets, Stars and Stellar Systems (PSSS), Volume 1:
Telescopes and Instrumentatio
Depth cues and perceived audiovisual synchrony of biological motion
Due to their different propagation times, visual and auditory signals from external events arrive at the human sensory receptors with a disparate delay. This delay consistently varies with distance, but, despite such variability, most events are perceived as synchronic. There is, however, contradictory data and claims regarding the existence of compensatory mechanisms for distance in simultaneity judgments.
Principal Findings:
In this paper we have used familiar audiovisual events – a visual walker and footstep sounds – and manipulated the number of depth cues. In a simultaneity judgment task we presented a large range of stimulus onset asynchronies corresponding to distances of up to 35 meters. We found an effect of distance over the simultaneity estimates, with greater distances requiring larger stimulus onset asynchronies, and vision always leading. This effect was stronger when both visual and auditory cues were present but was interestingly not found when depth cues were impoverished.
Significance:
These findings reveal that there should be an internal mechanism to compensate for audiovisual delays, which critically depends on the depth information available.FEDERFundação para a Ciência e a Tecnologia (FCT
Azimuthal anisotropy and correlations at large transverse momenta in and Au+Au collisions at = 200 GeV
Results on high transverse momentum charged particle emission with respect to
the reaction plane are presented for Au+Au collisions at =
200 GeV. Two- and four-particle correlations results are presented as well as a
comparison of azimuthal correlations in Au+Au collisions to those in at
the same energy. Elliptic anisotropy, , is found to reach its maximum at
GeV/c, then decrease slowly and remain significant up to
-- 10 GeV/c. Stronger suppression is found in the back-to-back
high- particle correlations for particles emitted out-of-plane compared to
those emitted in-plane. The centrality dependence of at intermediate
is compared to simple models based on jet quenching.Comment: 4 figures. Published version as PRL 93, 252301 (2004
Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV
The results from the STAR Collaboration on directed flow (v_1), elliptic flow
(v_2), and the fourth harmonic (v_4) in the anisotropic azimuthal distribution
of particles from Au+Au collisions at sqrtsNN = 200 GeV are summarized and
compared with results from other experiments and theoretical models. Results
for identified particles are presented and fit with a Blast Wave model.
Different anisotropic flow analysis methods are compared and nonflow effects
are extracted from the data. For v_2, scaling with the number of constituent
quarks and parton coalescence is discussed. For v_4, scaling with v_2^2 and
quark coalescence is discussed.Comment: 26 pages. As accepted by Phys. Rev. C. Text rearranged, figures
modified, but data the same. However, in Fig. 35 the hydro calculations are
corrected in this version. The data tables are available at
http://www.star.bnl.gov/central/publications/ by searching for "flow" and
then this pape
Borrelia Burgdorferi Induces a Type I Interferon Response During Early Stages of Disseminated Infection in Mice
BACKGROUND: Lyme borrelia genotypes differ in their capacity to cause disseminated disease. Gene array analysis was employed to profile the host transcriptome induced by Borrelia burgdorferi strains with different capacities for causing disseminated disease in the blood of C3H/HeJ mice during early infection.
RESULTS: B. burgdorferi B515, a clinical isolate that causes disseminated infection in mice, differentially regulated 236 transcripts (P \u3c 0.05 by ANOVA, with fold change of at least 2). The 216 significantly induced transcripts included interferon (IFN)-responsive genes and genes involved in immunity and inflammation. In contrast, B. burgdorferi B331, a clinical isolate that causes transient skin infection but does not disseminate in C3H/HeJ mice, stimulated changes in only a few genes (1 induced, 4 repressed). Transcriptional regulation of type I IFN and IFN-related genes was measured by quantitative RT-PCR in mouse skin biopsies collected from the site of infection 24 h after inoculation with B. burgdorferi. The mean values for transcripts of Ifnb, Cxcl10, Gbp1, Ifit1, Ifit3, Irf7, Mx1, and Stat2 were found to be significantly increased in B. burgdorferi strain B515-infected mice relative to the control group. In contrast, transcription of these genes was not significantly changed in response to B. burgdorferi strain B331 or B31-4, a mutant that is unable to disseminate.
CONCLUSIONS: These results establish a positive association between the disseminating capacity of B. burgdorferi and early type I IFN induction in a murine model of Lyme disease
Rapidity and Centrality Dependence of Proton and Anti-proton Production from Au+Au Collisions at sqrt(sNN) = 130GeV
We report on the rapidity and centrality dependence of proton and anti-proton
transverse mass distributions from Au+Au collisions at sqrt(sNN) = 130GeV as
measured by the STAR experiment at RHIC. Our results are from the rapidity and
transverse momentum range of |y|<0.5 and 0.35 <p_t<1.00GeV/c. For both protons
and anti-protons, transverse mass distributions become more convex from
peripheral to central collisions demonstrating characteristics of collective
expansion. The measured rapidity distributions and the mean transverse momenta
versus rapidity are flat within |y|<0.5. Comparisons of our data with results
from model calculations indicate that in order to obtain a consistent picture
of the proton(anti-proton) yields and transverse mass distributions the
possibility of pre-hadronic collective expansion may have to be taken into
account.Comment: 4 pages, 3 figures, 1 table, submitted to PR
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