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American Society for Testing and Materials

I. Introduction A FUNCTIONAL relationship between cell growth and the initiation and progression of events associated with differentiation has been a fundamental question challenging developmental biologists for more than a century. In the case of bone, as observed with other cells and tissue, the relationship of growth and differentiation must be maintained and stringently regulated, both during development and throughout the life of the organism, to support tissue remodeling. For many years, bone was defined anatomically and examined largely in a descriptive manner by ultrastructural analysis and by biochemical and histochemical methods. These studies provided the basis for our understanding of bone tissue organization and orchestration of the progressive recruitment, proliferation, and differentiation of the various cellular components of bone tissue. Now, complemented by an increased knowledge of molecular mechanisms that are associated with and regulate expression of genes encoding phenotypic compone...

Molecular mechanism mediating proliferation, defferentiation interralationships during progressie development of the osteoblast phenotype

Surface integrity in material removal processes: Recent advances

Manufacturing and measurement of freeform optics

Calcium phosphate coatings on magnesium alloys for biomedical applications: a review.

Single crystalline silicon was plunge-cut using diamond tools at a low speed. Cross-sectional transmission electron microscopy and laser micro-Raman spectroscopy were used to examine the subsurface structure of the machined sample. The results showed that the thickness of the machining-induced amorphous layer strongly depends on the tool rake angle and depth of cut, and fluctuates synchronously with surface waviness. Dislocation activity was observed below the amorphous layers in all instances, where the dislocation density depended on the cutting conditions. The machining pressure was estimated from the micro-cutting forces, and a subsurface damage model was proposed by considering the phase transformation and dislocation behavior of silicon under high-pressure conditions.

/pdf/fundamental-investigation-of-subsurface-damage-in-single-2ox111bp0s.pdf

Fundamental investigation of subsurface damage in single crystalline silicon caused by diamond machining

Octacalcium phosphate (OCP) has been advocated to be a precursor of biological apatite crystals in bones and teeth Our previous studies showed that synthetic OCP stimulates bone regeneration, followed by the progressive conversion of OCP into hydroxyapatite (HA), when implanted in bone defects However, the precise mechanism to induce the osteogenic phenotype in osteoblasts by OCP has not been identified The present study was designed to investigate whether the physicochemical aspect, specific to and derived from the structural properties of OCP, influences the function of an osteoblastic cell line, mouse bone marrow stromal ST-2 cells Different amounts of synthetic OCP and synthetic sintered ceramic HA were coated onto 48-well tissue culture plates The amounts of OCP and HA were controlled to strengthen their intrinsic physicochemical properties, in which the milieu around the crystals will be modified during the culture The roughness of the OCP coatings was independent of the amount of coating Chemical analyses of the supernatants of the OCP coatings revealed that the concentration of Ca2+ decreased with increasing amounts of OCP, while the concentration of inorganic phosphate increased markedly, most probably through OCP--apatite conversion ST-2 cells were cultured on the OCP or HA coatings up to day 21 The OCP coating caused a significant decrease in cell attachment and in the initial stage of proliferation, dependent upon the amount of coating On the other hand, OCP enhanced the expression of osteogenic markers, including type I collagen, alkaline phosphatase, and osterix However, HA did not alter the expression of these markers in ST-2 cells cultured on different amounts of HA coating These results demonstrated that OCP is capable of inducing the differentiation of stromal cells into osteoblastic cells, especially differentiation into early stage osteoblastic cells, prior to reaching the stage of mature osteoblastic cell lineage

Dose-dependent osteogenic effect of octacalcium phosphate on mouse bone marrow stromal cells.

https://www.yan.mech.keio.ac.jp/wp-site/wp-content/uploads/2Ductile-regime-turning-at-large-tool-feed.pdf

Ductile regime turning at large tool feed

Reaction-bonded silicon carbide (RB-SiC) is a new ceramic material that has extremely high strength and hardness. Diamond turning experiments were performed on RB-SiC to investigate the microscopic material removal mechanism. Diamond tools with large nose radii of 10 mm were used for machining. It was found that the surface roughness was not significantly affected by the tool feed rate, but was strongly dependent on the tool rake angle. The mechanism for material removal involved plastic deformation, microfracture and dislodgement of 6H-SiC grains. Raman spectroscopy revealed that the silicon bond component underwent amorphization, while no phase transformation of 6H-SiC grains was observed. Tool wear was also investigated and two types of wear patterns were identified. Under the experimental conditions used, a surface finish of 23 nm Ra was obtained even at an extremely high tool feed rate of 72 μm/rev. This study demonstrates the feasibility of precision machining of RB-SiC by diamond turning at a very high material removal rate.

Mechanism for material removal in diamond turning of reaction-bonded silicon carbide

http://www.yan.mech.keio.ac.jp/wp-site/wp-content/uploads/5Precision-machining-of-microstructures-on-electroless-plated-NiP-surface-for-molding-glass-components.pdf

Tsunemoto Kuriyagawa

Papers

Fundamental investigation of subsurface damage in single crystalline silicon caused by diamond machining

Dose-dependent osteogenic effect of octacalcium phosphate on mouse bone marrow stromal cells.

Ductile regime turning at large tool feed

Mechanism for material removal in diamond turning of reaction-bonded silicon carbide

Precision machining of microstructures on electroless-plated NiP surface for molding glass components