1,090 research outputs found
Further investigations of the effects of anti-β2GP1 antibodies on collagen-induced platelet aggregation
Anti-beta-2-glycoprotein 1 (anti-β2GP1) antibodies are associated with increased thrombotic risk in patients with autoimmune disease. There is conflicting evidence on the effects of anti-β2GP1 antibodies on platelets, with both enhanced and inhibited aggregation previously reported. However, previous studies did not include isotype antibodies to ensure the observed effects were due to anti-β2GP1 antibodies. The aims of this study were to (1) investigate the effects of anti-β2GP1 antibodies on collagen-induced platelet aggregation in parallel with negative control (buffer normal saline) and isotype control antibodies and (2) determine the lupus anticoagulant (LA) activity of anti-β2GP1 antibodies used. Three animal-derived anti-human-β2GP1 antibodies (1.25, 2.5, and 5 μg/mL) incubated with healthy platelet-rich plasma were activated by collagen (2.5 μg/mL). Each anti-β2GP1 antibody demonstrated the inhibition of aggregation compared to negative control, but not to isotype control. No anti-β2GP1 antibody demonstrated LA activity, suggesting they were probably nonpathological. This study highlights both negative and isotype control markers are important to validate the effects of anti-β2GP1 antibodies. Assays to measure anti-domain I-β2GP1 antibodies are recommended to be used in conjunction with functional measures to further investigate the effects of anti-β2GP1 antibodies
Ground State and Quasiparticle Spectrum of a Two Component Bose-Einstein Condensate
We consider a dilute atomic Bose-Einstein condensate with two non-degenerate
internal energy levels. The presence of an external radiation field can result
in new ground states for the condensate which result from the lowering of the
condensate energy due to the interaction energy with the field. In this
approach there are no instabilities in the quasiparticle spectrum as was
previously found by Goldstein and Meystre (Phys. Rev. A \QTR{bf}{55}, 2935
(1997)).Comment: 20 pages, 2 figures RevTex. Submitted to Phys. Rev. A; Revised
versio
Some effects of earthquakes at North Sumatra to the total electron content in the Ionosphere
Total Electron Content (TEC) is an important ionospheric and space weather param-
eter used for characterizing the state and dynamics of plasma in the ionosphere. As
a result, this study was carried out to examine the possible relationship between the
variations of the TEC in the ionosphere and the earthquakes and to identify the ef-
fects of earthquakes to the TEC in the ionosphere. The analysis of ionospheric TEC
variations were made using the Global Positioning System (GPS) station installed at
Wireless and Radio Science Centre (WARAS), Kolej Universiti Teknologi Tun Hus-
sein Onn (KUiTTHO), Johor (Latitude 1 ̊52 ́ N, longitude 103 ̊48 ́ E). Five cases of
strong earthquakes at Indonesia in 2005 with M
>
6.0 were selected as case studies.
The TEC variations analysis of the GPS TEC collected by the GPS receiver in the
year of 2005 were made to identify any TEC variations associated with earthquakes.
Pronounced TEC variations around the time of earthquakes were analyzed with re-
spect to the TEC variations during non-earthquake period. From the analysis, it was
found that there appears to be rapid changes in TEC within 0 to 6 days before the
earthquakes. Besides that, the TEC variations for all the cases show that the TEC
gradually recovered to normal within 1 to 3 days after earthquakes. As a conclusion,
strong earthquakes are reported to have caused disturbances in the ionosphere that
can be measured with GPS as short-period changes in the TEC. The ionospheric TEC
variations with average
∆
TEC = 10 TECU can be considered as a possible earthquake
precursory
Bandgap properties of two-dimensional low-index photonic crystals
We study the bandgap properties of two-dimensional photonic crystals created
by a lattice of rods or holes conformed in a symmetric or asymmetric triangular
structure. Using the plane-wave analysis, we calculate a minimum value of the
refractive index contrast for opening both partial and full two-dimensional
spectral gaps for both TM and TE polarized waves. We also analyze the effect of
ellipticity of rods and holes and their orientation on the threshold value and
the relative size of the bandgap.Comment: 5 pages, 6 figures, App. Phys. B. styl
Mitochondria transfer can enhance the murine embryo development
Purpose To evaluate the effect of mitochondrial transfer on embryonic development. Materials and methods Mitochondria concentrates were collected from murine hepatocytes and fertilized murine zygotes from young and older mice in the 2PN stage were subjected to mitochondrial transfer and cultured in vitro to evaluate the embryonic development. Results After extended in vitro culture, 37.65% and 20.91% embryos from the young mice developed to the blastocyst stage in the injected and control groups respectively, which is statistically significant. There was no difference in terms of hatching rates (1.76% and 1.82% respectively). Zygotes from the older mice (> 20 weeks old) that received mitochondrial transfer also had a better developmental outcome than the control group (54.35% and 18.92% developed to morula stage, 43.48% and 8.11% developed to the blastocyst stage respectively), which is statistically significant. Conclusions Our results for the murine model provide direct scientific evidence that mitochondrial transfer improves embryonic development. However, potential risks such as mitochondrial heteroplasmy, nuclear-mitochondrial interaction and epigenetic aspects all deserve further evaluation before mitochondrial transfer is applied clinically
Anisotropic conduction in the triangle of Koch of mammalian hearts: electrophysiologic and anatomic correlations
AbstractObjectives. The purpose of this study was to characterize anisotropy in the triangle of Koch by relating electrophysiology with anatomy.Background. Atrioventricular (AV) node fast and slow pathway characteristics have been suggested to be due to nonuniform anisotropy in the triangle of Koch.Methods. During atrial pacing, we determined the electrical activity within the triangle of Koch by multichannel mapping in 11 isolated hearts from pigs and dogs. Orientation of fibers was determined in nine hearts.Results. Fibers were parallel to the tricuspid valve annulus (TVA) in the posterior part of the triangle of Koch. In the midjunctional area, the direction of the fibers changed to an orientation perpendicular to the TVA. During stimulation from posterior and anterior sites, activation proceeded parallel to the TVA at a high conduction velocity (0.5 to 0.6 m/s). During stimulation from sites near the coronary sinus, a narrowzone of slow conduction occurred in the posterior part of the triangle of Koch where activation proceeded perpendicular to the fiber orientation. Above and below this zone, conduction was fast and parallel to the annulus. After premature stimulation, conduction delay in the triangle of Koch increased by 4 to 21 ms; in contrast, the AH interval increased by 80 to 210 ms.Conclusions. Data support the concept of anisotropic conduction in the triangle of Koch. Activation maps correlated well with the arrangement of superficial atrial fibers. Comparison of conduction delay in the triangle of Koch and AH delay after premature stimulation disproves that anisotropy in the superficial layers plays an important role in slow AV conduction
The Acoustic Peak in the Lyman Alpha Forest
We present the first simulation of the signature of baryonic acoustic
oscillations (BAO) in Lyman alpha forest data containing 180,000 mock quasar
sight-lines. We use eight large dark-matter only simulations onto which we
paint the Lyman alpha field using the fluctuating Gunn-Peterson approximation.
We argue that this approach should be sufficient for the mean signature on the
scales of interest. Our results indicate that Lyman alpha flux provides a good
tracer of the underlying dark matter field on large scales and that redshift
space distortions are well described by a simple linear theory prescription. We
compare Fourier and configuration space approaches to describing the signal and
argue that configuration space statistics provide useful data compression. We
also investigate the effect of a fluctuating photo-ionizing background using a
simplified model and find that such fluctuations do add smooth power on large
scales. The acoustic peak position is, however, unaffected for small amplitude
fluctuations (<10%). Larger amplitude fluctuations make the recovery of the BAO
signal more difficult and may degrade the achievable significance of the
measurement.Comment: 10 pages, 8 figures; v2: minor revision matching version accepted by
JCAP (new references, better figures, clarifications
Ensembles of probability estimation trees for customer churn prediction
Customer churn prediction is one of the most, important elements tents of a company's Customer Relationship Management, (CRM) strategy In tins study, two strategies are investigated to increase the lift. performance of ensemble classification models, i.e (1) using probability estimation trees (PETs) instead of standard decision trees as base classifiers; and (n) implementing alternative fusion rules based on lift weights lot the combination of ensemble member's outputs Experiments ale conducted lot font popular ensemble strategics on five real-life chin n data sets In general, the results demonstrate how lift performance can be substantially improved by using alternative base classifiers and fusion tides However: the effect vanes lot the (Idol cut ensemble strategies lit particular, the results indicate an increase of lift performance of (1) Bagging by implementing C4 4 base classifiets. (n) the Random Subspace Method (RSM) by using lift-weighted fusion rules, and (in) AdaBoost, by implementing both
Unparticles and Holographic Renormalization Group
We revisit the unparticle interactions and propagators from the AdS-CFT point
of view, and we show how the contact terms and their renormalization group flow
appear in the context of the holographic renormalization. We study both vector
unparticles and unfermions, uncovering the relevant boundary conditions and
renormalization group flows.Comment: 12 pages, version to appear in JHE
Higher order parametric X-ray spectra in mosaic graphite and single silicon crystals
We have observed up to eight orders (n) in the spectra of parametric x-radiation, in the range 5-40
keV, produced by the interaction of a 90 Mev electron beam with mosaic graphite and 90 and 35 Mev beams with single silicon crystals. The measured yields and intensity ratios, I(2)/I(n= I), in graphite
are not in agreement with the theory of PXR for mosaic crystals. In comparison, the yield and
ratios of intensities in silicon are close to the predictions of PXR theory for perfect crystals.
The bandwidths of spectral lines measured in both silicon and graphite are in good agreement with
theoretical predictions, and are determined by the angular field of view of the detector.U.S. Department of EnergyDNANaval Postgraduate SchoolContract No. DE-FG03-91ER8109
- …