A new cutting method for bone based on its crack propagation characteristics

The goal of the paper is to develop a machining process for biomaterials. Efficiency, mechanical stress, and precision are crucial parameters in the machining of living tissues, such as bone. The authors observed and analyzed the fracture of and crack propagation in bone, since crack generation cannot be avoided in bone machining, due to the brittle nature of the workpiece. A new cutting method is proposed based on the determined crack propagation characteristics. Through the use of this method, the required machining energy was decreased by utilizing the new insights concerning crack propagation and the surface roughness was improved, owing to the small finishing depth of cut.     

Investigation of TiC–C Eutectic and WC–C Peritectic High-Temperature Fixed Points

TiC–C eutectic (2,761°C) and WC–C peritectic (2,749°C) fixed points were investigated to compare their potential as high-temperature thermometric reference points. Two TiC–C and three WC–C fixed-point cells were constructed, and the melting and freezing plateaux were evaluated by means of radiation thermometry. The repeatability of the TiC–C eutectic within a day was 60 mK with a melting range roughly 200 mK. The repeatability of the melting temperature of the WC–C peritectic within 1 day was 17 mK with a melting range of ∼70 mK. The repeatability of the freezing temperature of the WC–C peritectic was 21 mK with a freezing range less than 20 mK. One of the TiC–C cells was constructed from a TiC and graphite powder mixture. The filling showed the reaction with the graphite crucible was suppressed and the ingot contained less voids, although the lack of high-purity TiC powder poses a problem. The WC–C cells were easily constructed, like metal–carbon eutectic cells, without any evident reaction with the crucible. From these results, it is concluded that the WC–C peritectic has more potential than the TiC–C eutectic as a high-temperature reference point. The investigation of the purification of the TiC–C cell during filling and the plateau observation are also reported.     

Improvement in long-term stability of dye-sensitized solar cell for outdoor use

To improve the intrinsic stability of the component of dye-sensitized solar cells (DSCs), we have fabricated the unit cell using solvent-free ionic liquid electrolyte. The degradation in the continuous 1 sun light soaking test at 60 °C over 15,000 h was effectively suppressed, compared with the cell using γ-butyrolactone electrolyte. The lifetime for outdoor use was estimated over 15 years from acceleration factor based on the outdoor exposure test. To confirm the stability of the DSC under practical outdoor use, we fabricated the solar light using the DSC modules, rechargeable batteries and bright light emitting diode (LED). The solar lights have been emitting a bright white light at night using the electricity from batteries charged by the DSC modules during the daytime in any weather condition for a half year.     

ECK, a human EPH-related gene, maps to 1p36.1, a common region of alteration in human cancers

Mouse eck, a member of the EPH gene family, has been mapped to mouse chromosome 4. The syntenic relationship between this chromosome and human chromosome 1 suggests that the human ECK gene maps to the distal short arm of human chromosome 1 (1p). Since this region is frequently deleted or altered in certain tumors of neuroectodermal origin, it is important to define the specific chromosomal localization of the human ECK gene. PCR screening of a rodent-human somatic cell hybrid panel by ECK-specific primers showed that ECK is indeed localized to human chromosome 1. Additional PCR screening of a regional screening panel for chromosome 1p indicated that ECK is localized to 1p36, distal to FUCA1. Furthermore, fluorescence in situ hybridization analysis with an ECK-specific P1 clone showed that ECK maps proximal to genetic marker D1S228. Taken together, the data suggest that ECK maps to 1p36.1, a region that is frequently deleted in neuroblastoma, melanoma, and other neuroectodermal tumors.     

Morphology of polystyrene/polystyrene-block-poly(methyl methacrylate)/poly(methyl methacrylate) composite particles

Polystyrene/polystyrene-block-poly(methyl methacrylate)/poly(methyl methacrylate) (PS/PS-b-PMMA/PMMA) composite particles were prepared by releasing toluene from PS/PS-b-PMMA/PMMA/toluene droplets dispersed in a sodium dodecyl sulfate aqueous solution. The morphology of the composite particles was affected by release rate of toluene, the molecular weight of PS-b-PMMA, droplet size, and polymer composition. ‘Onion-like’ multilayered composite particles were prepared from toluene droplets of PS-b-PMMA and of PS/PS-b-PMMA/PMMA, in which the weights of PS and PMMA were the same. The layer thicknesses of the latter multilayered composite particles increased with an increase in the amount of the homopolymers. PS-b-PMMA/PS composite particles had a sea-islands structure, in which PMMA domains were dispersed in a PS matrix. On the other hand, PS-b-PMMA/PMMA composite particles had a cylinder-like structure consisting of a PMMA matrix and PS domains.     

Product design for strong cover glass

Strength is one of the most important properties of cover glass. In this study, fracture analysis is used to classify the breakage mode of cover glass into four typical modes. Moreover, the mechanism and evaluation method of each mode are investigated. Consequently, a chemical strengthening design with high compressive stress (CS) and low center tension (CT) is obtained. In addition, processing design is determined to be an important factor. Fining of edge processing and surface polishing after chemical strengthening are shown to enhance the edge and surface strength, respectively.     

FORCE ANALYSIS OF ORTHOGONAL CUTTING OF BOVINE CORTICAL BONE

In orthopedic operations, no sound solutions exist to avoid conditions like tool breakage, bone fracture/cracks and thermal necrosis for lacking understanding of the mechanics of the bone cutting process. In this work, analysis of variance (ANOVA) and regression analysis were performed to investigate effects of cutting conditions on cutting and thrust forces based on a full factorial design. Then applicability of Merchant's analysis for calculating cutting force with respect to rake angle and feed was evaluated by comparison with experiments. Finally, the friction coefficient was evaluated by calculation. ANOVA shows that forces are much more sensitive to feed, cutting direction and rake angle than to cutting speed. Regression equations including all four factors were obtained by introduction of dummy variables. Cutting forces from experiments and from Merchant's analysis are partially comparable (maximum relative error = 34%) when feed and rake angle are changed. Friction coefficient was affected by rake angle and cutting direction. Cutting speed had little effect on the coefficient. These results can deepen the understanding of the mechanics of the bone-cutting process and assist the development of innovative cutting devices and selection of favorable cutting conditions for the procedure.     

Domain wall observation and dielectric anisotropy in PZN–PT by SPM

The voltage drops on the surfaces in PZN–20% PT and PZN–30% PT were investigated using the electrostatic force microscopy (EFM). It was found that the voltage drop per unit length in the a-domain is larger than the one in the c-domains on the sample surface with the ferroelastic domain wall structure, implying that the dielectric constant perpendicular to the spontaneous polarization is larger than the one parallel to the spontaneous polarization in the vicinity of the morphotropic phase boundary (MPB). Dielectric anisotropy in the vicinity of the MPB was discussed.