Cellular heterogeneity of mesenchymal stem cells (MSCs) impedes their use in regenerative medicine. The objective of this research is to identify potential biomarkers for the enrichment of progenitors from heterogeneo...
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Cellular heterogeneity of mesenchymal stem cells (MSCs) impedes their use in regenerative medicine. The objective of this research is to identify potential biomarkers for the enrichment of progenitors from heterogeneous MSC cultures. To this end, the present study examines variation in expression of neuron-glial antigen 2 (NG2) and melanoma cell adhesion molecule (CD146) on the surface of MSCs derived from human bone marrow in response to culture conditions and among cell populations. Multipotent cells isolated from heterogeneous MSC cultures exhibit a greater than three-fold increase in surface expression for NG2 and greater than two-fold increase for CD146 as compared with parental and lineage-committed MSCs. For both antigens, surface expression is downregulated by greater than or equal to six-fold when MSCs become confluent. During serial passage, maximum surface expression of NG2 and CD146 is associated with minimum doubling time. Upregulation of NG2 and CD146 during loss of adipogenic potential at early passage suggests some limits to their utility as potency markers. A potential relationship between proliferation and antigen expression was explored by sorting heterogeneous MSCs into rapidly and slowly dividing groups. Fluorescence-activated cell sorting revealed that rapidly dividing MSCs display lower scatter and 50% higher NG2 surface expression than slowly dividing cells, but CD146 expression is comparable in both groups. Heterogeneous MSCs were sorted based on scatter properties and surface expression of NG2 and CD146 into high (HI) and low (LO) groups. Sc(LO)NG2(HI) and Sc(LO)NG2(HI)CD146(HI) MSCs have the highest proliferative potential of the sorted groups, with colony-forming efficiencies that are 1.5-2.2 times the value for the parental controls. The Sc-LO gate enriches for rapidly dividing cells. Addition of the NG2(HI) gate increases cell survival to 1.5 times the parental control. Further addition of the CD146(HI) gate does not significantly impro
A method for fast measuring and identify the six geometric errors of each rotary axes in Four- axis machining center was invented. The method adopted the ball-bar to measure the X, Y, Z direction deviations of the cen...
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ISBN:
(纸本)9783037855034
A method for fast measuring and identify the six geometric errors of each rotary axes in Four- axis machining center was invented. The method adopted the ball-bar to measure the X, Y, Z direction deviations of the centre block installed on the rotary table in the different rotation angle. And deduced the geometric error identification model in rotary axes based homogeneous transformation, and then identify the axis of the six basic geometric errors. in order to reduce the influence of the inaccuracy of the ball-bar and the reference point position, this paper put forward new method based on the analysis of the sensitivity matrix method, used to guide rational distribution points, so as to improve the error identification accuracy.
Aspernigrin C (Ia) and D (Ib) are isolated as new compounds together with six known compounds from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30.
Aspernigrin C (Ia) and D (Ib) are isolated as new compounds together with six known compounds from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30.
The influence of ZnO substitution by 0-12 wt.% Na2O on the properties of ZnO-Sb2O3-P2O5-Na2O glasses has been investigated. The structure and properties of the glasses with the composition of (13.86-x)ZnO-57.93Sb(2)O(...
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The influence of ZnO substitution by 0-12 wt.% Na2O on the properties of ZnO-Sb2O3-P2O5-Na2O glasses has been investigated. The structure and properties of the glasses with the composition of (13.86-x)ZnO-57.93Sb(2)O(3)-28.21P(2)O(5-x)Na(2)O (x = 0-12 wt.%) were characterized by infrared spectra (IR), X-ray diffraction and differential thermal analysis (DTA). The results of IR indicated an increase in the intensity of symmetric vibrations of P-O-P bond, which was confirmed by the improvement of water durability with the increasing amount of Na2O in the range of 0-10 wt.%. Substitution of 10 wt.% Na2O led to the weight loss of the glass to 5.93 mg/cm(-2) after immersion in deionized water at 50 degrees C for 24 h. The results of XRD showed that the ability of crystallization decreased, indicating the good thermal stability of the glass. The glass containing 8 wt.% Na2O had the best properties in every respect and might be an alternative to lead based glasses for the applications, providing further composition improvement.
There exist several honeycomb networks exhibiting zero Poisson's ratio (ZPR). Applications of these networks can be found in different fields. The ZPR properties of these structures have been mechanically modeled ...
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There exist several honeycomb networks exhibiting zero Poisson's ratio (ZPR). Applications of these networks can be found in different fields. The ZPR properties of these structures have been mechanically modeled and tested. However, the underlying mechanism driving the ZPR behavior has not been paid much attention. The present work focuses on the deformation mechanism of the ZPR networks. Through the discussion and comparison of the deformation process of the ZPR, auxetic and common honeycomb networks, the strain-isolation mechanism is proposed to explain the ZPR behavior. Then, according to this mechanism, the reversed semi-re-entrant (RSRE) honeycomb is created. With experimental measurements and finite-element analysis (FEA), the ZPR properties of the RSRE can be proven. The strain-isolation mechanism can not only explain the ZPR behavior but also be used in the design of new ZPR honeycomb networks. 3D ZPR structures are also derived from the 2D honeycomb networks. Their Poisson's ratios in 3D space are also discussed based on FEA results. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
In allusion to the deficiencies existing in current structural optimization algorithm of excavator boom such as the inefficiency in expressing and handling the constraints, the insufficiency in adopting the task knowl...
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ISBN:
(纸本)9783037853726
In allusion to the deficiencies existing in current structural optimization algorithm of excavator boom such as the inefficiency in expressing and handling the constraints, the insufficiency in adopting the task knowledge to direct constraint handling, and the difficulty in obtaining and adopting the optimal process knowledge, a new method of the constraints expression and handling based on cultural algorithm for excavator boom structural optimization is put forward. The mechanism of hierarchical constraints expression and handing is established to improve the efficiency of the constraint handling in the optimal process with the cultural algorithm as frame and the task knowledge as guide. And the hierarchical topographical knowledge is formed to express tacit knowledge in the population space. Then the process of constraints expressing and handling as well as its interaction with the knowledge base is discussed under the direction of dual evolution in cultural algorithm while the aim of acquisition, expression and handling for tacit constraints knowledge in optimal process is realized. Finally, structural optimization of an excavator boom is taken as an example to demonstrate the effectiveness of this method.
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