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본 연구는 프로젝트 관리, 건축공학, 경영학 및 정보통신기술을 융합하여 건설 프로젝트 관리기술 의 향상을 그 목적으로 한다. 기존의 데이터베이스 활용 프로젝트 관리기술의 한계와 초고층 건물과 같은 초대형 건설공사의 다양한 리스크를 극복하고, 건축 프로젝트 등의 특수성을 감안한 전략적 관 리기술의 개발의 필요성에 부합하기 위하여 본 연구는 주제중심 프로젝트 관리라는 개념을 제안하고, 이를 뒷받침하는 활용 모델을 개발하여 주제지수(Subject Index)라는 개념을 통한 건설 프로젝트 관리 의 효율성 제고 방안을 제시한다. 본 연구를 통하여 제안된 SPM 모델은 초고층 건축 프로젝트 관리기술에서 데이터/정보/지식관리 의 개념을 넘어서는 새로운 관리의 패러다임이 되고, 본 모델의 핵심개념인 주제지수는 실제 현장에 서 활용되어 우리나라의 건설기술과 경영기술의 발전 및 현재 정부가 추진하고 있는 창조경제 정책 실현에도 도움이 되는 중요한 도구가 될 것으로 기대된다.

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene which encodes dystrophin protein. Dystrophin defect affects cardiac muscle as well as skeletal muscle. Cardiac dysfunction is observed in all patients with DMD over 18 years of age, but there is no curative treatment for DMD cardiomyopathy. To establish novel experimental platforms which reproduce the cardiac phenotype of DMD patients, here we established iPS cell lines from T lymphocytes donated from two DMD patients, with a protocol using Sendai virus vectors. We successfully conducted the differentiation of the DMD patient-specific iPS cells into beating cardiomyocytes. DMD patient-specific iPS cells and iPS cell-derived cardiomyocytes would be a useful in vitro experimental system with which to investigate DMD cardiomyopathy.

Hydroxyapatite (HA) is widely used as a bioactive ceramics as it forms a chemical bond with bone. However, the drawback to using this material is its inferior mechanical properties. In this research, surface corrosion and disintegration of nanoscaled HA in a dog were studied, and the mechanism by which phase-pure HA dissolved In Vivo was investigated. Biological properties of HA In Vivo are affected by the grain-boundary dissolution followed by a surface corrosion and microstructural disintegration. This kind of dissolution process, apparently evidenced at the grain boundary, causes particle generation, which indicates that both long-term bone in-growth and mechanical properties can dramatically deteriorate. Implant dissolution by osteoclasts In Vivo is also observed on the surface of hydroxyapatite. Implant surface showed an aggressive corrosion by an osteoclast resorption. Severe and deeper dissolution underwent close to osteoclast resulting in formation of smaller and more round particle shape.

Surface modification with a biphasic composition of hydroxyapatite (HA) and tricalcium phosphate (TCP) was performed on a zirconia substrate using a sol-gel method. An initial calcium phosphate sol was prepared by mixing a solution of Ca(NO3)2 · 4H20 and (C2H5O)3P(O), while both porous and dense zirconia were used as substrates. The sol-gel coating was performed using a spin coater. The coated porous zirconia substrate was re-sintered at 1350 °C 2 h, while coated dense zirconia substrate was heat-treated at 750 °C 1 h. The microstructure of the resultant HA/TCP coatings was found to be dependent on the type of zirconia substrate used. With porous zirconia as a starting substrate, numerous isolated calcium phosphate particles (TCP and HA) were uniformly dispersed on the surface, and the particle size and covered area were dependent on the viscosity of the calcium phosphate sol. Conversely, when dense zirconia was used as a starting substrate, a thick film of nano-sized HA particles was obtained after heat treatment, however, substantial agglomeration and cracking was also observed.

A throat plug is a device in a shock tunnel to prevent fragments, produced by the bursting of the primary diaphragm, from entering the nozzle and damaging the model. In the present study, a series of experimental and numerical studies has been carried out to investigate the flows around stationary throat plugs in a shock tunnel. For this purpose, conical, circular, and double circular stationary throat plugs that have a 19.4% areal blockage were used as the test models. The primary shock velocity was set at 1.19 km/s, and the shock generated a tailored condition when helium and air were used as the driver and driven gases at room temperature. In the experiment, the nozzle reservoir pressure and the pitot pressure at the nozzle exit were measured to examine the influence of the throat plug. It was found that, from both the experiment and the calculation, all types of the plugs generate a pressure bump in the nozzle reservoir during the transient period of interaction between the reflected shock and the pl...

In a reflected shock tunnel, stagnation conditions of a nozzle are determined by the flow behind a reflected shock. When calculating the flow behind the reflected shock, unlike a shock tube, the flow leakage through the nozzle is to be considered. The analytical studies were done to find out the characteristics of the stagnation conditions of the nozzle with various nozzle throat size. Experiments and numerical simulations were also carried out for further understanding of the flow leakage effects. It was found that the nozzle stagnation pressure was diminished by the increase of the size of the nozzle throat. It was also found that the steady pressure in the stagnation were maintained well at the area ratio of the driven tube to the nozzle throat is 4.5.

A series of experimental study has been conducted to investigate the flow associated with a moving throat plug in a shock tunnel testing. Bird et al [1] employed the moving throat plug to prevent upstream diaphragm fragments from entering the nozzle and blasting the model in the shock tunnel testing.

Active nanoscale powders of cubic phase zirconia stabilized with yttria, gadolinia, and scandia were successfully prepared by urea hydrolysis. Synthetic cubic zirconia powders had homogeneous, nanoscale, and less-agglomeration characteristics. Dense pellets of grain size about 0.4 μm exhibited grain boundary blocking resistance compared to the high frequency bulk resistance. Gadolinium doped system exhibited highest ionic resistivity. Yttria stabilized zirconia by urea hydrolysis in this work showed smaller ionic resistivity than the sample prepared from the commercial powder.

Microfluidics technology has been exploited in single cell study because of its ability to manipulate particles and control over culture conditions. Two drawbacks of the existing studies are that (1) they require large supporting equipment like an incubator and a syringe pump; which involves more culture media volume, and that (2) the trapped cells are isolated from one another that cell interaction is obstructed or not considered. These limit the applications and advantages of microfluidics compared to conventional petri dish method. In this study, centrifugal microfluidics is utilized to trap single cells of primary cultures of neonatal rat cardiomyocyte with controlled separation distance. Cell growth, coupling, and beating are successfully observed and monitored in the fabricated microfluidic device without large supporting equipment. Coupling and decoupling dynamics, that is a first to be observed in cardiomyocyte cell microfluidics, can be proven useful in the headway of controlled cell growth and orientation research. Furthermore, these findings can be applied to future chip design and operation for cardiomyocyte studies and high-throughput lab on-a-chip devices.

Hydroxyapatite coatings were fabricated by a room temperature spray method on zirconia substratesand the influence of heat-treatment on their microstructure was also investigated. Phase composition of coatedhydroxyapatite films was similar to the starting powder, but the grain size of hydroxyapatite particles was reducedto the size of nano-scale about 100 nm. Grain size, particle compactness, and adhesiveness to zirconia ofhydroxyapatite coatings were increased with heat-treatment temperature, but some of cracks by heat-treatmentabove 1100 o C were initiated between hydroxyapatite coatings and zirconia substrate. Heat-treated hydroxyapa-tite layers show the dissolution in SBF solution for 5 days. Hydroxyapatite-coated specimen heat-treated at1100 o C for 1 h has a good biocompatibility, which specimen induced the nanocrystalline hydroxyapatite precipi-tates on the coating surface by the immersion in SBF solution for 5 days. (Received December 26, 2014; Revised December 31, 2014; Accepted January 6, 2015)Key words : Hydroxyapatite coating, Room temperature spray, Zirconia, Heat-treatment

Nano size ZrO2 dispersed in Al2O3/ ZrO2 composite ceramics have been fabricated by chemical routes for the improvement of mechanical properties. In case of mechanical mixing of Al2O3 with ZrO2 powder homogeneous dispersion and controlling the ZrO2 size were relatively difficult during sintering. So hydrolysis method for preparing zirconium hydroxide from ZrOCl2· 8H2O and Y(NO3)3 6H2O directly with commercial sub-micron sized α-alumina (Sumitomo:AES-11(0.5μm)) was adapted, and by this method ZrO2 distribution was more uniform than mechanical mixing. But because of the relatively high sintering temperature of Al2O3 ceramics, dispersed ZrO2 particles grown up to 200 to 500nm at sintering temperature of 1500∼1600°C. So in order to decrease the sintering temperature of Al2O3/ZrO2 ceramics, high purity α-alumina (Taimei Chemical (0.22μm)) was used and dispersed ZrO2 particle size could be controlled below 200nm at sintering temperature of 1400∼1500°C.

This study was performed to investigate the water repellent effectiveness of natural oil-applied soil when it is used as a building material. Natural oil types such as olive oil, bean oil, perilla oil and linseed oil, which are being used for producing water repellent timber, are selected for the experiments. It is expected that perilla oil and in seed oil, which are drying oil types will have better water repellent effectiveness than the other types. For the evaluation of water repellence of natural oil-applied soil, a contact angle test was performed. A contact angle of water drop on various surface conditions were tested, and large differences were seen between the natural oil-applied soil and untreated soil. As a result, it is showed that all natural oil types have water repellent effectiveness. However, linseed oil, which is a drying oil type, shows an outstanding water repellent effectiveness value, while perila oil, which is also a drying oil type, shows the lowest value. Additionally, results show that there is no link between water repellent effectiveness and the number of applications of natural oil. Nevertheless, existing commercial water repellents show better performance than natural oil, and it is anticipated that the results of this study will provide essential information for further research to enhance the water repellent effectiveness of soil as a building material.

Background The sympathetic nervous system is critical in maintaining the normal physiological function of the heart. Its dysfunction in pathological states may exacerbate the substrate for arrhythmias. Obviously, knowledge of its three-dimensional (3D) structure is important, however, it has been revealed by conventional methods only to a limited extent. In this study, a new method of tissue clearance in combination with immunostaining unravels the 3D structure of the sympathetic cardiac network as well as its changes after myocardial infarction. Methods and results Hearts isolated from adult male mice were optically cleared using the CUBIC-perfusion protocol. After making the hearts transparent, sympathetic nerves and coronary vessels were immunofluorescently labeled, and then images were acquired. The spatial distribution of sympathetic nerves was visualized not only along the epicardial surface, but also transmurally. They were distributed over the epicardial surface and penetrated into the myocardium to twist around coronary vessels, but also independent from the coronary vasculature. At 2 weeks after myocardial infarction, we were able to quantify both denervation distal from the site of infarction and nerve sprouting (hyperinnervation) at the ischemic border zone of the hearts in a 3D manner. The nerve density at the ischemic border zone was more than doubled in hearts with myocardial infarction compared to intact mice hearts (3D analyses; n = 5, p

The DNA damage response (DDR) plays a pivotal role in maintaining genome integrity. DNA damage and DDR activation are observed in the failing heart, however, the type of DNA damage and its role in the pathogenesis of heart failure remain elusive. Here we show the critical role of DNA single-strand break (SSB) in the pathogenesis of pressure overload-induced heart failure. Accumulation of unrepaired SSB is observed in cardiomyocytes of the failing heart. Unrepaired SSB activates DDR and increases the expression of inflammatory cytokines through NF-κB signalling. Pressure overload-induced heart failure is more severe in the mice lacking XRCC1, an essential protein for SSB repair, which is rescued by blocking DDR activation through genetic deletion of ATM, suggesting the causative role of SSB accumulation and DDR activation in the pathogenesis of heart failure. Prevention of SSB accumulation or persistent DDR activation may become a new therapeutic strategy against heart failure., DNA damage response (DDR) is activated in cardiomyocytes of the failing heart, but the type of DNA damage leading to DDR is unclear. Higo et al. show that in mice heart failure is caused in part by unrepaired DNA single-strand breaks in cardiomyocytes, which activate persistent DDR and trigger an NF-κB-dependent cardiac inflammation.

Engineering of three-dimensional (3D) cardiac tissues using decellularized extracellular matrix could be a new technique to create an "organ-like" structure of the heart. To engineer artificial hearts functionally comparable to native hearts, however, much remain to be solved including stable excitation-propagation. To elucidate the points, we examined conduction properties of engineered tissues. We repopulated the decellularized hearts with neonatal rat cardiac cells and then, we observed excitation-propagation of spontaneous beatings using high resolution cameras. We also conducted immunofluorescence staining to examine morphological aspects. Live tissue imaging revealed that GFP-labeled-isolated cardiac cells were migrated into interstitial spaces through extravasation from coronary arteries. Engineered hearts repopulated with Ca(2+)-indicating protein (GCaMP2)-expressing cardiac cells were subjected to optical imaging experiments. Although the engineered hearts generally showed well-organized stable excitation-propagation, the hearts also demonstrated arrhythmogenic propensity such as disorganized propagation. Immunofluorescence study revealed randomly-mixed alignment of cardiomyocytes, endothelial cells and smooth muscle cells. The recellularized hearts also showed disarray of cardiomyocytes and markedly decreased expression of connexin43. In conclusion, we successfully demonstrated that the recellularized hearts showed dynamic excitation-propagation as a "whole organ". Our strategy could provide prerequisite information to construct a 3D-engineered heart, functionally comparable to the native heart.

This study consists of the development and presentation of example of seismic isolation system analysis and design for a continuous, 3-span, cast-in-place concrete box girder bridge. It is expected that example is developed for all Lead-Rubber Bearing (LRB) seismic isolation system on piers and abutments which placed in between super-structure and sub-structure. Design forces, displacements, and drifts are given distinctive consideration in accordance with Caltrans Seismic Design Criteria (2004). Most of all, total displacement on design for all LRBs case is reduced comparing with combined lead-rubber and elastomeric bearing system . Therefore, this represents substantial reduction in cost because of reduction of expansion joint. This presents a summary of analysis and design of seismic isolation system by energy mitigation with LRB on bridges.

Notch signaling is involved in an intercellular communication mechanism that is essential for coordinated cell fate determination and tissue morphogenesis. The biological effects of Notch signaling are context-dependent. We investigated the functional and hierarchical relationship between angiotensin (Ang) II receptor signaling and Notch signaling in vascular smooth muscle cells (VSMCs). A fluorogenic substrate assay revealed directly that the enzymatic activity of γ-secretase was enhanced after 10 min of Ang II stimulation in HEK293 cells expressing Ang II type 1 receptor. Notch cleavage by γ-secretase was consistently induced and peaked at 10 min after Ang II stimulation, and the Ang II-stimulated increase in Notch intracellular domain production was significantly suppressed by treatment with the γ-secretase inhibitor DAPT. Treatment with DAPT also significantly reduced the Ang II-stimulated proliferation and migration of human aortic VSMCs, as revealed by BrdU incorporation and the Boyden chamber assay, respectively. Systemic administration of the γ-secretase inhibitor dibenzazepine reduced Ang II-induced medial thickening and perivascular fibrosis in the aortas of wild-type mice. These findings suggest that the hierarchical Ang II receptor-Notch signaling pathway promotes the proliferation and migration of VSMCs, and thereby contributes to the progression of vascular remodeling.

Amphotericin B (AmB) has been widely used against fungal infections throughout almost the entire body, including the skin, nails, oral cavity, respiratory tract, and urinary tract. However, the development of AmB-loaded nanoparticles demands a novel technique that reduces its toxicity and other associated problems. Here, we developed a pH-responsive and redox-sensitive polymer-based AmB-delivery carrier system. In particular, this system was functionalized by conjugation with the antifungal peptide histatin 5, which acts both as a targeting ligand and a synergistic antifungal molecule against Candida albicans, a major systemic fungal pathogen of humans. Our results in vitro and in vivo suggest that this drug-delivery system may serve as a novel tool to facilitate the use of antimicrobial peptides as targeting ligands to pathogenic microbes, which would open new avenues of investigation in the field of drug delivery.

Hypersonic flow field around a flight vehicle has density fluctuating elements such as shock wave and boundary layer. Since refractive index of light is related to density of medium, light propagation path changes while passing through the flow field. Influence of flow field property on optical characteristics is called aero-optics. As in Fig. 1, aero-optics distorts the image obtained by an optical instrument on the flight vehicle and degrades light intensity, displaces the position of an object, blurs the image, etc. To avoid these effects, various studies were conducted to relate optical characteristics with flow characteristics and to measure aero-optical aberration.

Usually, the forepart of an optical-guided missile generally composes of the body with a cone or hood shape and the optical window to seek a target. Additionally, a cooling system is necessary to reduce the surface temperature of the optical window when a missile system is flying in hypersonic flow fields, because the aero-optical window of a missile can undergo severe aerodynamic heating problems causing high heat and cracks to optical windows which eventually lead to failure of optical windows.

Densification and mechanical properties of dental zirconia ceramics were evaluated by different sintering methods. Y-TZP zirconia block was used in this study. Sintering were performed in electric heating furnace and microwave sintering furnace, and then experimented and analyzed on a change in densification according to the sintering time, a change in densification according to thickness, flexural strength and micro-structure of zirconia specimens. Microwave sintering was very effective in considerable mechanical properties such as flexural strength and bulk density was drastically increased than conventional electric heating method. It is also shown that microwave sintering was faster and more economical than common method to be present in qualities which equal or exceed. It will be important to seek the accurate sintering condition of dental zirconia by microwave sintering method and the continuous research is necessary for the study of relationship between sintering methods and mechanical properties.

In this study, we investigated the crack nucleation and growth and propagation on the surface of Y-TZP during isothermal phase transformation by low temperature ageing. Crack initiation and growth on the surface of Y-TZP specimen was dependent on the sintered microstructure, i.e, sintered density, grain size, pore structure, residual stress etc.. In the case of Y-TZP with 2mol % yttria content, phase transformation of tetragonal to monoclinic began on the surface and induced a crack nucleation of specimen at the initial stage of low temperature ageing. Most of cracks in 2Y-TZP by low temperature ageing were firstly formed on the surface of specimens (free surface, weak bonding grains, etc.) where the change of strain free energy for a tetragonal to monoclinic transformation was small, and surface cracks grew into the bulk interior through the grain boundaries.

Magnesium ion substituted biphasic calcium phosphate (Mg-BCP) bioceramic microscaffolds with spherical and porous morphology were successfully prepared usingin situcoprecipitation and rotary spray drying atomization process for application of tissue engineering combined with human adipose tissue-derived mesenchymal stem cells (hAT-MSCs). After 4 weeks of immersion in Hanks’ balanced salt solution (HBSS), Mg-BCP micro-scaffolds showed the enhanced biodegradation and bioactivity due to the substituted Mg2+ion present in the BCP structure. In this study, it was observed that hAT-MSCs have clearly attached on the surface of Mg-BCP micro-scaffolds. In addition, Mg-BCP micro-scaffolds exhibited the improved biocompatibility and osteoconductivity viain vitroandin vivobiological tests with hAT-MSCs. Therefore, these bioceramic micro-scaffolds had potential to be used as hAT-MSCs microcarriers for biomedical applications.

We present herein a first proof of concept demonstrating the potential of a protein nanopore-based technique for real-time detection of selected Gram-negative bacteria (Pseudomonas aeruginosa or Escherichia coli) at a concentration of 1.2 × 108 cfu/mL. The anionic charge on the bacterial outer membrane promotes the electrophoretically driven migration of bacteria towards a single α-hemolysin nanopore isolated in a lipid bilayer, clamped at a negative electric potential, and followed by capture at the nanopore’s mouth, which we found to be described according to the classical Kramers’ theory. By using a specific antimicrobial peptide as a putative molecular biorecognition element for the bacteria used herein, we suggest that the detection system can combine the natural sensitivity of the nanopore-based sensing techniques with selective biological recognition, in aqueous samples, and highlight the feasibility of the nanopore-based platform to provide portable, sensitive analysis and monitoring of bacterial pathogens. Electronic supplementary material The online version of this article (doi:10.1186/s11671-016-1715-z) contains supplementary material, which is available to authorized users.

Cardiac fibrosis is a pathological feature of myocardium of failing heart and plays causative roles in arrhythmia and cardiac dysfunction, but its regulatory mechanisms remain largely elusive. In this study, we investigated the effects of the novel EP4 receptor agonist ONO-0260164 on cardiac fibrosis in hypertrophied heart and explored the regulatory mechanisms in cardiac fibroblasts.In a mouse model of cardiac hypertrophy generated by transverse aortic constriction (TAC), ONO-0260164 treatment significantly prevented systolic dysfunction and progression of myocardial fibrosis at 5 weeks after TAC. In cultured neonatal rat cardiac fibroblasts, transforming growth factor-β1 (TGF-β1) induced upregulation of collagen type 1, alpha 1 (Col1a1) and type 3, alpha 1 (Col3a1), which was inhibited by ONO-0260164 treatment. ONO-0260164 activated protein kinase A (PKA) in the presence of TGF-β1 in the cardiac fibroblasts. PKA activation suppressed an increase in collagen expression induced by TGF-β1, indicating the important inhibitory roles of PKA activation in TGF-β1mediated collagen induction.We have demonstrated for the first time the antifibrotic effects of the novel EP4 agonist ONO-0260164 in vivo and in vitro, and the important role of PKA activation in the effects.

Activation of β-catenin-dependent canonical Wnt signaling in endothelial cells plays a key role in angiogenesis during development and ischemic diseases, however, other roles of Wnt/β-catenin signaling in endothelial cells remain poorly understood. Here, we report that sustained activation of β-catenin signaling in endothelial cells causes cardiac dysfunction through suppressing neuregulin-ErbB pathway in the heart. Conditional gain-of-function mutation of β-catenin, which activates Wnt/β-catenin signaling in Bmx-positive arterial endothelial cells (Bmx/CA mice) led to progressive cardiac dysfunction and 100% mortality at 40 weeks after tamoxifen treatment. Electron microscopic analysis revealed dilatation of T-tubules and degeneration of mitochondria in cardiomyocytes of Bmx/CA mice, which are similar to the changes observed in mice with decreased neuregulin-ErbB signaling. Endothelial expression of Nrg1 and cardiac ErbB signaling were suppressed in Bmx/CA mice. The cardiac dysfunction of Bmx/CA mice was ameliorated by administration of recombinant neuregulin protein. These results collectively suggest that sustained activation of Wnt/β-catenin signaling in endothelial cells might be a cause of heart failure through suppressing neuregulin-ErbB signaling and that the Wnt/β-catenin/NRG axis in cardiac endothelial cells might become a therapeutic target for heart failure.

For the past few years, the video surveillance market has shown a rapid growth due to the increasing demand for Closed Circuit Television(CCTV) by the public sector and the private security industry. While the overall utilization of CCTV in the public and private sectors is expanding, its usage in the field of disaster management is less than sufficient. Therefore, the authors of this study, in an effort to revisit the role of CCTV in disaster situations, have carried out a case analysis in the vicinity of the Gangnam Station which has been designated as a natural disaster-prone area. First, the CCTV images around the target location are collected and the time and depth of inundation are measured through field surveys and image analyses. Next, a rainfall analysis was conducted using the Automatic Weather Station(AWS) data and the past inundation records. Lastly, the authors provide an estimate of rainfall for the areas around the station and suggest viable warning systems and countermeasures. The results from this study are expected to make positive contributions towards a significant reduction of the damages caused by the floods around the Gangnam Station.

Removed due to double publication

Refractory castables containing calcium aluminate cement (CAC) are widely used in a range of furnace lining applications in the iron and steel, cement, glass, ceramic, and petrochemical industries. However, magnesia-phosphate cement (MPC) based material could be a new types of cement material, with many advantages such as rapid hydration, high early strength and circumstance suitability, which has very important value and wide application. In this study, MPC was used at Chromia/Alumina castable as binder addition instead of conventional calcium aluminate cement. Meanwhile, it also explains the relationship between the micro-mechanism and performance by micro methods such as SEM. The results shows that MPC based castables have good corrosion resistance, interface adhesiveness and abrasion resistance.

Biphasic calcium phosphate bioceramics were fabricated from the recycling of bone ash which is mostly used as raw materials of bone china. Precursor calcium phosphate powders were prepared by soaking the commercial bone ash in 0.1 M of NaOH solution at 80°C for 4 h. Calcium phosphate powders was obtained by calcination at 800°C for 1 h to completely remove residual organics. Biphasic calcium phosphate bioceramics which is composed of hydroxyapatite and tricalcium phosphate was fabricated by the sintering of pressed compacts at 1200°C for 1 h under moisture protection. The bone ash derived-biphasic calcium phosphate ceramics consists of mostly HA and small amounts of α-tricalcium phosphate, magnesium oxide and calcium oxide. After polishing the HA ceramics, they were immersed in buffered water at 37°C for 3 and 7 days. The bone ash derived- biphasic calcium phosphate ceramics show high biostability in liquid environment with immersion time compared with commercial calcium phosphate ceramics.

This work describes dissolution and related mechanical weakening of phase-pure and dense hydroxyapatite (HA) in distilled water of pH 7.4. Phase-pure HA powder has been synthesized by a wet precipitation method. After uniaxial and cold isostatic pressing, and sintering at 1200°C, dense HA with 98% above of the theoretical density has been obtained. The results show that HA powder has stoichiometric composition with a Ca/P ratio 1.67 ± 0.02. Even after extended exposure for 10 h, no second phases, such as tricalcium phosphate (TCP) and calcium oxide can be observed. Although the HA is supposed to be stable in liquid environment, surface dissolution appears specifically at material’s grain boundaries after immersion for 7 days. Following further immersion to 14 days, grain boundary dissolution progresses interior to the bulk following these paths. This dissolving behavior generates HA particles, disintegrates dense microstructure and at least forms micron-scale cavity. Mechanical property of the HA has been also affected. Fracture toughness (KIc) of the HA sintered body is approximately 1.0 MPa•m1/2. It drastically decreases to almost half of the initial value due to the severe surface dissolution

In situ preparation of magnesium (Mg) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/β-tricalcium phosphate (β-TCP) were carried out through aqueous co-precipitation method. The concentrations of added magnesium were varied with the calcium in order to obtain constant (Ca + Mg)/P ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized magnesium substituted BCP powders. The results have shown that substitution of magnesium in the calcium deficient apatites revealed the formation of biphasic mixtures of different HAp/β-TCP ratios after heating at 1000 °C. The ratios of the formation of phase mixtures were dependent on the content of magnesium. After immersing in Hanks’ balanced salt solution (HBSS) for 1 week, 1 wt% magnesium substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. On the other hand, in the case of pure BCP powders, the formation of new precipitates was detected after immersion in HBSS for 2 weeks. On the basis of these results, magnesium substituted BCP could be able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. In addition, the retention time to produce the new apatite phase in implantation operation for the BCP powder could be controlled by the amount of magnesium substitution.

Natural hydroxyapatite powder was obtained from the calcination of bovine bones and its porous compacts were fabricated by pressureless sintering at 1100 and for 1h. To evaluate and compare their biocompatibility with porosity, we investigated the support of osteoblast cells growth and cytotoxicity using the MG-63 cell line model in vitro. Sintered hydroxyapatite ceramics have a porous microstructure with a relative density of 65 % at and 82 % at . Cells adherence to the surface of hydroxyapatite ceramics was observed in a day after the cell culture, and the spreading of cytoplasm around the nucleus was shown after 3 day cell culture. Most of cells were extended to the surface of hydroxyapatite through the wide area. Cell viability was nearly the same till 3 days culturing. But the rate of cell growth is higher in the specimen sintered at than that of . It indicates that the porosity is an important factor to enhance the cell viability in the porous hydroxyapatite ceramics derived from bovine bones.

SummaryWnt signaling plays critical roles in development of various organs and pathogenesis of many diseases, and augmented Wnt signaling has recently been implicated in mammalian aging and aging-related phenotypes. We here report that complement C1q activates canonical Wnt signaling and promotes aging-associated decline in tissue regeneration. Serum C1q concentration is increased with aging, and Wnt signaling activity is augmented during aging in the serum and in multiple tissues of wild-type mice, but not in those of C1qa-deficient mice. C1q activates canonical Wnt signaling by binding to Frizzled receptors and subsequently inducing C1s-dependent cleavage of the ectodomain of Wnt coreceptor low-density lipoprotein receptor-related protein 6. Skeletal muscle regeneration in young mice is inhibited by exogenous C1q treatment, whereas aging-associated impairment of muscle regeneration is restored by C1s inhibition or C1qa gene disruption. Our findings therefore suggest the unexpected role of complement C1q in Wnt signal transduction and modulation of mammalian aging.

A throat plug is a device to prevent fragments produced by the bursting of the primary diaphragm of a shock tunnel from entering the nozzle and damaging the model. An experimental study has been carried out to investigate the flow in the KAIST shock tunnel with two stationary throat plugs at primary shock velocities of 1.19 and 1.28 km/s. These shocks generate tailored conditions when helium and air are used as the driver and driven gases, respectively, at room temperature. Nozzle reservoir pressures and Pitot pressures at the nozzle exit are measured to examine the influence of the stationary throat plug on these properties. The throat plug that has an areal blockage of 6.2 % is found to have negligible effects on shock tunnel flow. However, the throat plug of 19.4 % blockage shows an appreciable influence by generating a pressure bump. Although it retards the establishment time of the nozzle flow, after the transient period, it does not cause deviation of the pressure from that for the clean nozzle configuration. It is found that the reduction of the cross-sectional area, which results from the presence of the throat plug, causes the pressure bump. By increasing the diameter of the driven tube in the region where the throat plug is located appropriately, the magnitude of the pressure bump is reduced significantly.

In a previous study, an antifungal protein, AFP-J, was purified from tubers of the potato (Solanum tuberosum cv. L Jopung) and by gel filtration and HPLC. In this study, the functional peptide was characterized by partial acid digestion using HCl and HPLC. We obtained three peaks from the AFP-J, the first and third peaks were not active in the tested fungal strain. However, the second peak, which was named Potide-J, was active (MIC; 6.25 mu g/mL) against Candida albicans. The amino acid sequences were analyzed by automated Edman degradation, and the amino acid sequence of Potide-J was determined to be Ala-Val-Cys-Glu-Asn-Asp-Leu-Asn-Cys-Cys. Mass spectrometry showed that its molecular mass was 1083.1 Da. Finally, we confirmed that a disulfide bond was present between Cys(3) and Cys(9) or Cys(10). Using this structure, Potide-J was synthesized via solid-phase methods. In these experiments, only the linear sequence was shown to display strong activity against Candida albicans. These results suggest that Potide-J may be an excellent candidate compound for the development of commercially applicable antibiotic agents.

Effect of grain size on microstructure, transformation characteristics and shape recovery has been studied in Fe-24%Mn-4%Si-5%Cr-5%Co shape memory ribbons fabricated by melt spinning. Mean grain size of the ribbons could be controlled by wheel speed; in case of ribbon manufactured in the wheel speed of 10 m/sec, mean grain size was more or less 20 μm, while the mean grain size in 50 m/sec was about 1 μm. Thermal ε-martensite in the shape of plate could be observed in austenite matrix and the volume fraction of that decreased in smaller grains because of grain constraint. As a grain size decreased, one-way and two-way shape recoveries were increased. A change in shape recovery of ribbons was closely related to deformation mode i.e., transformation-induced plasticity or slip according to grain size; it could be confirmed that reversible ε-martensite was induced in preference to irreversible slip in the ribbon with smaller grains during deformation by X-ray diffractometry. Not like in bulk specimen, ε-martensite being very thin in the width of 10 ~ 20 nm and lots of stacking faults being inferred from streaks of SAD patterns, were revealed in melt-spun ribbons manufactured in the wheel speed of 50 m/sec.

Hydroxyapatite (HA) ceramics were prepared from the bone ash which is mostly used as animal feeds or raw materials. Dissolving behaviors of the HA in buffered water were investigated and compared with commercial HA for further use as biomaterials. HA ceramics were prepared by soaking the bone ash in 0.1 M of NaOH solution at 80°C for 4 h. The ash was calcined at 800°C for 1 h to completely remove organics, and then sintered at 1200°C for 1 h under moisture protection. The bone ash derived-HA consists of mostly HA and small amounts of α-tricalcium phosphate, calcium oxide phosphate, magnesium oxide and calcium oxide. After polishing the HA ceramics, they were immersed in buffered water at 37°C for 3 and 7 days. We previously found that grain boundaries of synthetic HA were intensively dissolved in buffered water. On the other hand, the bone ash derived-HA shows high stability in liquid environment with immersion time compared with commercial HA.

In situ preparation of silicon (Si) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/ β-tricalcium phosphate (β-TCP) were carried out through aqueous co-precipitation method. The concentrations of added silicon were varied with the phosphor in order to obtain constant Ca/(P+Si) ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized silicon substituted BCP powders. The characterization revealed that the formation of biphasic mixtures of different HAp/ β-TCP ratios was dependent on the content of silicon. After immersing in Hanks' balanced salt solution (HBSS) for 1 week, 3 wt% silicon substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. In the case of 1 wt% silicon substituted BCP powders, the degradation behavior was detected after immersion in HBSS for 3 weeks. On the other hand, silicon unsubtituted BCP powders were not degraded even after that duration. On the basis of these results, silicon substituted BCP is able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. This enhanced reactivity resulted in reduction for the stability of the β-TCP structure due to SiO 4 tetrahedral distortion and disorder at the hydroxyl site when silicon incorporates into BCP.

Mechanical degradation of hydroxyapatite ceramics due to the slow crack growth was observed in water. Microstructural crack on the surface of hydroxyapatite initiated by grain boundary dissolution in liquid environment resulting in particle loosening and microstructural-level degradation, followed by a drastic decrease of mechanical properties. In this study, slow crack growth by the dissolution behavior of hydroxyapatite ceramics was investigated based on microstructural observation by field emission microscopy. The crack growth and morphological change of hydroxyapatite surface, especially at the initial stage of dissolution and related surface roughness were observed with immersion time. The surface dissolution occurred from the initial stage of immersion showing increase in surface roughness. Following certain period of immersion time, the surface dissolution initiated at grain boundaries and generated many separated grains.

To replace bottom ash for natural sand completely, the mix proportions of bottom ash in concrete was adjusted according to tab density and replacement ratio of polymeric resin/Potland cement(PC) were established. And then testing for slump, setting time, and compressive strength was conducted. According to test results, the compressive strength of concrete using the bottom ash was lower than that of concrete using natural sand (BA0 concrete). But by adjusting the amount of bottom ash in concrete according tab density so that the fine aggregate proportions change 44% to 38%, the compressive strength of concrete using the bottom ash could even be higher than BA0 concrete. And as the polymeric resin content of bottom ash concrete increased, strength would be increased drastically, but proper dispersant should be cooperated with polymeric resin cement with fine bottom ash powders.

To understand the detailed mechanisms of arrhythmia and methods of its treatment, it is necessary to elucidate the mechanisms of formation and breakdown of cardiac beating at a microscopic level by using appropriate in vitro models of cardiac beating. We developed a method for medium-exchange-free culture of rat cardiac myocytes, and carried out long-term recording of the electrical activity of cardiac myocytes from postnatal rats by means of a microelectrode array (MEA) and our new culture method. Figures 6(a) to 6(f) show a series of properties of spontaneous beating (mean beating interval, standard deviation, and coefficient of variation) of cardiac myocytes cultured by a conventional culture method with alternate-day medium exchange [(a) to (c)] and the newly developed “molecular diffusion culture” method [(d) to (f)]. As shown in these figures, the difference in the beating property between individual cultures that is found in conventional cultures [(a) to (c)] is dramatically reduced in the molecular diffusion cultures [(d) to (f)]. These results also indicate that there is a transient period when the mean beating interval, the standard deviation, and the coefficient of variation all increase transiently before the formation of a stable rhythmic fast beat. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(7): 35–42, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10244

Congestive heart failure (CHF) predisposes to ventricular fibrillation (VF) in association with electrical remodeling of the ventricle. However, much remains unknown about the rate-dependent electrophysiological properties in a failing heart. Action potential properties in the left ventricular subepicardial muscles during dynamic pacing were examined with optical mapping in pacing-induced CHF ( n = 18) and control ( n = 17) rabbit hearts perfused in vitro. Action potential durations (APDs) in CHF were significantly longer than those observed for controls at basic cycle lengths (BCLs) >1,000 ms but significantly shorter at BCLs

Rat superior cervical ganglion (SCG) neurons and the ventricular myocytes (VMs) were cocultured in chambers made of polydimethylsiloxane. The chambers were placed on a microelectrode array (MEA) substrate and connected with a pathway. Twenty-four hours after dissemination of the VMs, neurites of the SCG neurons outgrew through the pathway and reached the VMs. Spontaneous electrical activities of the SCG neurons and the VMs were observed several days after the dissemination. Constant-voltage stimulation (1 V, 1 ms, biphasic square pulses) was applied to the SCG neurons at the frequency of 10 Hz using 32 electrodes. Contraction rate of the VMs increased by 153 ± 110% immediately after the stimulation to the SCG neurons was stopped. Then contraction rate gradually decreased and returned to almost the same rate as before the stimulation 5 min after the stimulation. Propranolol (β-adrenergic receptor antagonist) prevented contraction rate of the VMs from increasing after electrical stimulation to the SCG neurons. These results suggest that neuromuscular junctions were formed between the SCG neurons and the VMs and that this coculture system can be utilized in the research of cell–cell interactions between the sympathetic neurons and the cardiomyocytes. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Pseudomonas aeruginosa has eventually developed resistance against flomoxef sodium, isepamicin and cefpiramide. Therefore, in this study, the antibacterial activity and synergistic effects of the amphipathic-derived P5-18mer antimicrobial peptide were tested against pathogens associated with cholelithiasis that have developed resistance against commonly used antibiotics. The results were then compared with the activities of the amphipathic-derived peptide, P5-18mer, melittin and common antibiotics. Growth inhibition of planktonic bacteria was tested using the National Committee for Clinical Laboratory Standards (NCCLS). The bactericidal activity of the antimicrobial peptides was measured using time-kill curves. Synergistic effects were evaluated by testing the effects of P5-18mer alone and in combination with flomoxef sodium, isepamicin or cefpiramide at 0.5xMIC. P5-18mer peptide displayed strong activity against pathogens and flomoxef sodium, isepamicin and cefpiramide-resistant bacteria cell lines obtained from a patient with gallstones; however, it did not exert cytotoxicity against the human keratinocyte HaCat cell line. In addition, the results of time-kill curves indicated that P5-18mer peptide exerted bactericidal activity against four strains of P. aeruginosa. Finally, the use of P5-18mer and antibiotics exerted synergistic effects against cell lines that were resistant to commonly used antibiotics. These results indicate that this class of peptides has a rapid microbicidal effect on flomoxef sodium, isepamicin and cefpiramide-resistant strains of P. aeruginosa. Therefore, these peptides may be used as a lead drug for the treatment of acquired pathogens from patients with cholelithiasis who are affected with antibiotic-resistant bacteria.

Bone ash-derived hydroxyapatite (HA) ceramics were prepared by pressureless sintering and hot pressing, and their dissolution behavior was examined in buffered water. HA powder was obtained by soaking bone ash in a 0.1M NaOH solution at 80 °C, followed by calcination at 1000 °C to completely remove the organic material. The crystal structure of the HA powder with a particle size of approximately 1 μm was mainly hydroxyapatite with a minimal amount of α-tricalcium phosphate. To improve densification, the powder was hot-pressed at 1000 °C for 0.5 h under a pressure of 30 MPa in an Ar atmosphere. The sintered density of the hot-pressed HA was 95 % of the theoretical density, which is much higher than the 70% obtained for the pressureless-sintered compact. In the porous HA ceramics obtained by pressureless sintering, dissolution occurred adjacent to the pores rather than in the dense part, which increased the residual porosity. On the other hand, the hot-pressed HA showed grain boundary dissolution followed by particle loosening.