14,898 research outputs found

    Characteristics of Alveolar Bone Marrow Cells from Patients Undergoing Dental Extractions or Dental Implant Therapy

    Get PDF
    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

    Full text link
    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

    Full text link
    The magic proton and neutron numbers are searched in the superheavy region with proton number ZZ=100 - 140 and neutron number NN= (ZZ+30) - (2ZZ+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 S2pS_{2p} and S2nS_{2n}, the two-nucleon gaps δ2p\delta_{2p} and δ2n\delta_{2n}, the shell correction energies EshellpE_{shell}^{p} and EshellnE_{shell}^{n}, the pairing energies EpairpE_{pair}^{p} and EpairnE_{pair}^{n}, and the pairing gaps Δp\Delta_{p} and Δn\Delta_{n}, ZZ=120, 132, and 138 and NN=172, 184, 198, 228, 238, and 258 are suggested to be the magic numbers within the present approach. The α\alpha-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 172292^{292}_{172}120 and 184304^{304}_{184}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

    Get PDF
    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

    Get PDF
    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

    Full text link
    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

    Full text link
    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

    Full text link
    Using the tadpole improved clover Wilson quark action on small, coarse and anisotropic lattices, KNKN 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
    corecore