14,898 research outputs found
Characteristics of Alveolar Bone Marrow Cells from Patients Undergoing Dental Extractions or Dental Implant Therapy
Alveolar bone marrow stromal cells (aBMSCs) play important roles in craniofacial wound healing. To establish an easy, efficient and reliable method to harvest aBMSCs, we compared three different methods: extraction socket aspiration, osteotomy aspiration and bone core digestion. Samples of aBMSC were collected from two groups of subjects. Group 1 (dental extraction): after dental extraction, 22.5-gauge needles were used to collect 0.5-1cc marrow aspirate. Group 2 (dental implant): during implant surgeries, bone core and 0.5-1cc marrow aspirate were obtained from the osteotomy. Samples were cultured in petri dishes and attached cells were expanded. The population doubling time (PDT), surface markers, and osteogenic differentiation potential of these cells were studied. In total 12 subjects were enrolled in the study. The success rates of generating aBMSCs from extraction socket aspiration, osteotomy aspiration and bone core digestion were 42.8% (3/7), 40% (2/5) and 80% (4/5), respectively. Cells from extraction socket aspiration had the fastest proliferation rate among the three sample types, followed by bone core and osteotomy aspiration, as shown in PDTs and DNA fold changes. After isolation and expansion, all the aBMSCs expressed high levels of CD 73, CD90, and CD105, however, the expression of CD146 varied among the cells. Cells derived from bone core had the highest ALP activity after osteogenic induction, followed by cells from osteotomy aspiration, and then extraction aspiration. Taken together, bone core samples obtained during implant surgery is a more reliable source for generating aBMSCs and aBMSCs harvested from different methods may have different characteristics
Momentum-space electronic structures and charge orders of high-temperature superconductors Ca2-xNaxCuO2Cl2 and Bi2Sr2CaCu2O8+delta
We study the electronic structure of Ca2-xNaxCuO2Cl2 and Bi2Sr2CaCu2O8+d
samples in a wide range of doping, using angle-resolved photoemission
spectroscopy, with emphasis on on the Fermi surface (FS) in the near anti-nodal
region. The "nesting wave vector", i.e., the wave vector that connects two
nearly flat pieces of the Fermi surface in the anti-nodal region, reveals a
universal monotonic decrease in magnitude as a function of doping. Comparing
our results to the charge order recently observed by scanning tunneling
spectroscopy (STS), we conclude that the FS nesting and the charge order
pattern seen in STS do not have a direct relationship. Therefore,the charge
order likely arises due to strong correlation physics rather than FS nesting
physics.Comment: 6 pages, 4 figure
Magic numbers for superheavy nuclei in relativistic continuum Hartree-Bogoliubov theory
The magic proton and neutron numbers are searched in the superheavy region
with proton number =100 - 140 and neutron number = (+30) - (2+32)
by the relativistic continuum Hartree-Bogoliubov (RCHB) theory with
interactions NL1, NL3, NLSH, TM1, TW99, DD-ME1, PK1, and PK1R. Based on the
two-nucleon separation energies and , the two-nucleon gaps
and , the shell correction energies
and , the pairing energies and ,
and the pairing gaps and , =120, 132, and 138 and
=172, 184, 198, 228, 238, and 258 are suggested to be the magic numbers
within the present approach. The -decay half-lives are also discussed.
In addition, the potential energy surfaces of possible doubly magic nuclei are
obtained by the deformation-constrained relativistic mean field (RMF) theory,
and the shell effects stabilizing the nuclei are investigated. Furthermore, the
formation cross sections of 120 and 120 at the
optimal excitation energy are estimated by a phenomenological cold fusion
reactions model with the structure information extracted from the constrained
RMF calculation.Comment: 37 pages, 14 figure
Robot competence development by constructive learning
This paper presents a constructive learning approach for developing sensor-motor mapping in autonomous systems. The system's adaptation to environment changes is discussed and three methods are proposed to deal with long term and short term changes. The proposed constructive learning allows autonomous systems to develop network topology and adjust network parameters. The approach is supported by findings from psychology and neuroscience especially during infants cognitive development at early stages. A growing radial basis function network is introduced as a computational substrate for sensory-motor mapping learning. Experiments are conducted on a robot eye/hand coordination testbed and results show the incremental development of sensory-motor mapping and its adaptation to changes such as in tool-use
Diarrhoea scores and weight changes in response to artificial milk supplementation or use of solulyte-neomycin solution in preweaning piglets
The objective of this study was to determine the effects of supplemental milk replacer and solulyte-neomix solution in preweaning piglets. A total of 199 five-day-old piglets from 22litters were available for this three-week study. 12 litters (110 piglets) were allocated into the milk replacer supplemented group (MILK), five litters (47 piglets) were allocated into the ELEC group which was given an antibiotic-fortified electrolyte solution for pigs, and five litters (45 piglets) remained as untreated control (CTRL). However, after matching for litter size and total litter weights among treatment groups, only 44 piglets (5litters) in the MILK group, 47 piglets (5 litters) in the ELEC group and 45 piglets from 5 litters in the CTRL group were considered in this report. All sows were fed the same diet (18 % protein, 3,952 kcal of ME/kg). Body weights of piglets were measured at days 5 and 25 of age. Fresh liquid commercial milk replacer and solulyte-neomix solution were prepared daily. The fluids were offered thrice daily at 100mL per litter for 5-day-old piglets. Supplementation was increased to 5 times daily at 200mL per litter when piglets were 9 days or older, till the end of the trial. Average litter weight gain was higher in the ELEC piglets given solulyte-neomix
solution and creep feed (P<0.05). Milk replacer supplemented group (MILK) generally had lower average litter
weight gains at 3.72 kg. However, the diarrhea scores were affected by the types of supplementation fluids given. The
overall diarrhoea scores were higher in the MILK and CTRL piglets compared to the ELEC piglets. In conclusion, milk replacer supplementation offered no obvious benefit in terms of weight gain, final weight, and overall diarrhoea
scores in piglets compared to solulyte-neomix supplemented piglets
Robust 6D Object Pose Estimation by Learning RGB-D Features
Accurate 6D object pose estimation is fundamental to robotic manipulation and
grasping. Previous methods follow a local optimization approach which minimizes
the distance between closest point pairs to handle the rotation ambiguity of
symmetric objects. In this work, we propose a novel discrete-continuous
formulation for rotation regression to resolve this local-optimum problem. We
uniformly sample rotation anchors in SO(3), and predict a constrained deviation
from each anchor to the target, as well as uncertainty scores for selecting the
best prediction. Additionally, the object location is detected by aggregating
point-wise vectors pointing to the 3D center. Experiments on two benchmarks:
LINEMOD and YCB-Video, show that the proposed method outperforms
state-of-the-art approaches. Our code is available at
https://github.com/mentian/object-posenet.Comment: Accepted at ICRA 202
Codimension Two Branes in Einstein-Gauss-Bonnet Gravity
Codimension two branes play an interesting role in attacking the cosmological
constant problem. Recently, in order to handle some problems in codimension two
branes in Einstein gravity, Bostock {\it et al.} have proposed using
six-dimensional Einstein-Gauss-Bonnet (EGB) gravity instead of six-dimensional
Einstein gravity. In this paper, we present the solutions of codimension two
branes in six-dimensional EGB gravity. We show that Einstein's equations take a
"factorizable" form for a factorized metric tensor ansatz even in the presence
of the higher-derivative Gauss-Bonnet term. Especially, a new feature of the
solution is that the deficit angle depends on the brane geometry. We discuss
the implication of the solution to the cosmological constant problem. We also
comment on a possible problem of inflation model building on codimension two
branes.Comment: 16 pages, no figures. v2: References added; v3: Reference added,
Sec.4 and 5 combined into one; v4: References added, minor corrections, to
appear in Physical Review
Lattice study on kaon nucleon scattering length in the I=1 channel
Using the tadpole improved clover Wilson quark action on small, coarse and
anisotropic lattices, scattering length in the I=1 channel is calculated
within quenched approximation. The results are extrapolated towards the chiral
and physical kaon mass region. Finite volume and finite lattice spacing errors
are also analyzed and a result in the infinite volume and continuum limit is
obtained which is compatible with the experiment and the results from Chiral
Perturbation Theory.Comment: 15 pages, 4 figures, typeset by latex using elsart.cls,minor change
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