937 research outputs found
Isolation of microsatellite markers for Bletilla striata and cross-amplification in other related species
Bletilla is a temperate, terrestrial genus of orchids containing 6 species. For the species whose whole genome is unknown, we used magnetic bead hybridization method to develop microsatellite Simple Repeat Polymorphoresis (SSR) for Bletilla striata and 9 primer sets were characterized in two wild populations of B. striata and one wild population of Bletilla ochracea. The number of alleles per locus ranged from 1 to 12. The expected and observed heterozygosities ranged from 0 to 0.7646 and 0 to 0.950 in B. striata, respectively. In B. ochracea, the expected and observed heterozygosities ranged from 0.296 to 0.871 and 0.05 to 1, respectively. The 9 pairs of primers we designed can be used to distinguish different ecotypes and species, and might be used for other subspecies or species in genera Bletilla.Keywords: Bletilla striata, cross-species amplification, simple repeat polymorphoresis (SSR)
Modeling and simulation of sintering process across scales
Sintering, as a thermal process at elevated temperature below the melting
point, is widely used to bond contacting particles into engineering products
such as ceramics, metals, polymers, and cemented carbides. Modelling and
simulation as important complement to experiments are essential for
understanding the sintering mechanisms and for the optimization and design of
sintering process. We share in this article a state-to-the-art review on the
major methods and models for the simulation of sintering process at various
length scales. It starts with molecular dynamics simulations deciphering
atomistic diffusion process, and then moves to microstructure-level approaches
such as discrete element method, Monte--Carlo method, and phase-field models,
which can reveal subtle mechanisms like grain coalescence, grain rotation,
densification, grain coarsening, etc. Phenomenological/empirical models on the
macroscopic scales for estimating densification, porosity and average grain
size are also summarized. The features, merits, drawbacks, and applicability of
these models and simulation technologies are expounded. In particular, the
latest progress on the modelling and simulation of selective and direct-metal
laser sintering based additive manufacturing is also reviewed. Finally, a
summary and concluding remarks on the challenges and opportunities are given
for the modelling and simulations of sintering process.Comment: 45 pages, 38 figure
Three-dimensional structure and cytokine distribution of platelet-rich fibrin
OBJECTIVES: Previous reports have revealed that several cytokines (including platelet-derived growth factor-BB, transforming growth factors-β1 and insulin-like growth factor-1) can enhance the rate of bone formation and synthesis of extracellular matrix in orthopaedics or periodontology. This study aimed to determine the concentration of cytokines within platelet-rich fibrin microstructures and investigate whether there are differences in the different portions of platelet-rich fibrin, which has implications for proper clinical use of platelet-rich fibrin gel. METHODS: Whole blood was obtained from six New Zealand rabbits (male, 7 to 39 weeks old, weight 2.7-4 kg); it was then centrifuged for preparation of platelet-rich fibrin gels and harvest of plasma. The resultant platelet-rich fibrin gels were used for cytokine determination, histological analyses and scanning electron microscopy. All plasmas obtained were subject to the same cytokine determination assays for the purpose of comparison. RESULTS: Cytokines platelet-derived growth factor-BB and transforming growth factor-β1 formed concentration gradients from high at the red blood cell end of the platelet-rich fibrin gel (p=1.88×10-5) to low at the plasma end (p=0.19). Insulin-like growth factor-1 concentrations were similar at the red blood cell and plasma ends. The porosities of the platelet-rich fibrin samples taken in sequence from the red blood cell end to the plasma end were 6.5% ± 4.9%, 24.8% ± 7.5%, 30.3% ± 8.5%, 41.4% ± 12.3%, and 40.3% ± 11.7%, respectively, showing a gradual decrease in the compactness of the platelet-rich fibrin network. CONCLUSION: Cytokine concentrations are positively associated with platelet-rich fibrin microstructure and portion in a rabbit model. As platelet-rich fibrin is the main entity currently used in regenerative medicine, assessing cytokine concentration and the most valuable portion of PRF gels is essential and recommended to all physicians
Spectroscopy of broad absorption line quasars at -- I: evidence for quasar winds shaping broad/narrow emission line regions
We present an observational study of 22 broad absorption line quasars (BAL
QSOs) at based on optical/near-IR spectroscopy, aiming
to investigate quasar winds and their effects. The near-IR spectroscopy covers
the \hb\ and/or \mgii\ broad emission lines (BELs) for these quasars, allowing
us to estimate their central black hole (BH) masses in a robust way. We found
that our BAL QSOs on average do not have a higher Eddington ratio than that
from non-BAL QSOs matched in redshift and/or luminosity. In a subset consisting
of seven strong BAL QSOs possessing sub-relativistic BAL outflows, we see the
prevalence of large \civ-BEL blueshift (3100 km s) and weak \oiii\
emission (particularly the narrow \oiii5007 component), indicative of
nuclear outflows affecting the narrow emission-line (NEL) regions. In another
subset consisting of thirteen BAL QSOs having simultaneous observations of
\mgii\ and \hb, we found a strong correlation between 3000~\AA\ and 5000~\AA\
monochromatic luminosity, consistent with that from non-BAL QSOs matched in
redshift and luminosity; however, there is no correlation between \mgii\ and
\hb\ in FWHM, likely due to nuclear outflows influencing the BEL regions. Our
spectroscopic investigations offer strong evidence that the presence of nuclear
outflows plays an important role in shaping the BEL/NEL regions of these
quasars and possibly, regulating the growth of central supermassive black holes
(SMBHs). We propose that BEL blueshift and BAL could be different
manifestations of the same outflow system viewed at different sightlines and/or
phases.Comment: 13 pages, 10 figures. Accepted for publication in Ap
Discovery of gamma-ray emission from a strongly lobe-dominated quasar 3C 275.1
We systematically analyze the 6-year {\it Fermi}/LAT data of the
lobe-dominated quasars (LDQs) in the complete LDQ sample from 3CRR survey and
report the discovery of high-energy -ray emission from 3C 275.1. The
-ray emission of 3C 207 is confirmed and significant variability of the
lightcurve is identified. We do not find statistically significant -ray
emission from other LDQs. 3C 275.1 is the known -ray quasar with the
lowest core dominance parameter (i.e., ). We also show that both the
northern radio hotspot and parsec jet models can reasonably reproduce the
-ray data. The parsec jet model, however, is favored by the potential
-ray variability at the timescale of months. We suggest that some
dimmer -ray LDQs will be detected in the future and LDQs could
contribute non-negligibly to the extragalactic -ray background.Comment: 26 pages, 10 figures, 3 tables; ApJ in pres
Interference of Two-Dimensional Bose-Einstein Condensates in Micro-Gravity
We investigate the interference of two-dimensional Bose-Einstein condensates
in micro-gravity, which influenced by the interaction strength, initial
momentum, gravitational potential and phase difference. We demonstrate that the
gravitational potential from the Earth can change the density distribution and
phase distribution of the condensate's wave function. As time evolves, a
portion of the gravitational potential energy of the microscopic particles can
be converted into kinetic energy, which changes the motion of the microscopic
particles, and leads to the varying of the density and phase distribution of
the wave function. Nevertheless, the influences of the Earth's gravity on the
wave function can be eliminated by the micro-gravity environment, which
confirmed by many micro-gravity cold atom experiments. Our results present the
influences of gravity and other parameters on interference of Bose-Einstein
condensates, which help us to reveal the intrinsic natures of the related
theoretical predictions and experimental phenomena. Furthermore, our work
builds a bridge between the related physical phenomena and our physical
intuition about the Bose-Einstein condensates in micro-gravity environment
Statistical Origin of Constituent-Quark Scaling in the QGP hadronization
Nonextensive statistics in a Blast-Wave model (TBW) is implemented to
describe the identified hadron production in relativistic p+p and
nucleus-nucleus collisions. Incorporating the core and corona components within
the TBW formalism allows us to describe simultaneously some of the major
observations in hadronic observables at the Relativistic Heavy-Ion Collider
(RHIC): the Number of Constituent Quark Scaling (NCQ), the large radial and
elliptic flow, the effect of gluon saturation and the suppression of hadron
production at high transverse momentum (pT) due to jet quenching. In this
formalism, the NCQ scaling at RHIC appears as a consequence of non-equilibrium
process. Our study also provides concise reference distributions with a least
chi2 fit of the available experimental data for future experiments and models.Comment: 4 pages, 3 figures; added two tables, explained a little bit more on
TBW_p
Effect of Xinyue capsules on patients with coronary heart disease after percutaneous coronary intervention: study protocol for a randomized controlled trial
Case report form 2014.3.4R2. (PDF 1119 kb
Quasar winds caught on acceleration and deceleration
We present an observational study of wind acceleration based on four
low-ionization broad absorption line (LoBAL) quasars (J0136, J1238, J1259,
J1344). J0136 and J1344 (group-1) are radio quiet and show large BAL-velocity
shifts as opposed to stable line-locking associated absorption lines (AALs).
Notably, J1344 displays a linear relation between BAL-velocity shift and time
interval over three consecutive epochs, characteristic of compelling evidence
for BAL acceleration. J1238 and J1259 (group 2) exhibit small BAL-velocity
shifts along with steep-spectrum, weak radio emission at 3.0 and 1.4 GHz. All
four quasars have spectral energy distributions (SEDs) with a peak at
m, suggesting a link between the BAL
acceleration and hot dust emission. The group-2 quasars are redder than group-1
quasars and have a steeper rise at m in their
SEDs. All but J1238 exhibit a steep rise followed by a plateau-like time
evolution in BAL-velocity shift. Our investigations, combined with previous
studies of BAL acceleration, indicate that (1) the BAL-ISM coupling process is
one of the major avenues for the origin of quasar reddening and patchy
obscuration, (2) AAL outflows are ubiquitous and likely signify large-scale
remnants of BAL winds coupled to interstellar medium (ISM), and (3) wind
deceleration that is closely linked to the BAL-ISM coupling process may produce
weak radio emission in otherwise radio-quiet quasars.Comment: 19 pages, 9 figures, accepted for publication in ApJ
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