3,894 research outputs found
A modified porous titanium sheet prepared by plasma activated sintering for biomedical applications
This study aimed to develop a contamination free porous titanium scaffold by
a plasma activated sintering within an originally developed TiN coated graphite
mold. The surface of porous titanium sheet with or without a coated graphite
mold was characterized. The cell adhesion property of porous titanium sheet was
also evaluated in this study. The peak of TiC was detected on the titanium
sheet processed with the graphite mold without a TiN coating. Since the
titanium fiber elements were directly in contact with the carbon graphite mold
during processing, surface contamination was unavoidable event in this
condition. The TiC peak was not detectable on the titanium sheet processed
within the TiN coated carbon graphite mold. This modified plasma activated
sintering with the TiN coated graphite mold would be useful to fabricate a
contamination free titanium sheet. The number of adherent cells on the modified
titanium sheet was greater than that of the bare titanium plate. Stress fiber
formation and the extension of the cells were observed on the titanium sheets.
This modified titanium sheet is expected to be a new tissue engineering
material in orthopedic bone repair.Comment: 5 pages, 4 figure
Whole body counter surveys of Miharu-town school children for four consecutive years after the Fukushima NPP accident
Comprehensive whole-body counter surveys of Miharu town school children have
been conducted for four consecutive years, in 2011-2014. This represents the
only long-term sampling-bias-free study of its type conducted after the
Fukushima Dai-ichi accident. For the first time in 2014, a new device called
the Babyscan, which has a low Cs MDA of Bq/body, was used to
screen the children shorter than 130 cm. No child in this group was found to
have detectable level of radiocesium. Using the MDAs, upper limits of daily
intake of radiocesium were estimated for each child. For those screened with
the Babyscan, the upper intake limits were found to be <1 Bq/day for
Cs. Analysis of a questionnaire filled out by the children's parents
regarding their food and water consumption shows that the majority of Miharu
children regularly consume local and/or home-grown rice and vegetables. This
however does not increase the body burden.Comment: 11 pages, 10 figure
Maximally Satisfying Lower Quotas in the Hospitals/Residents Problem with Ties
Motivated by the serious problem that hospitals in rural areas suffer from a shortage of residents, we study the Hospitals/Residents model in which hospitals are associated with lower quotas and the objective is to satisfy them as much as possible. When preference lists are strict, the number of residents assigned to each hospital is the same in any stable matching because of the well-known rural hospitals theorem; thus there is no room for algorithmic interventions. However, when ties are introduced to preference lists, this will no longer apply because the number of residents may vary over stable matchings.
In this paper, we formulate an optimization problem to find a stable matching with the maximum total satisfaction ratio for lower quotas. We first investigate how the total satisfaction ratio varies over choices of stable matchings in four natural scenarios and provide the exact values of these maximum gaps. Subsequently, we propose a strategy-proof approximation algorithm for our problem; in one scenario it solves the problem optimally, and in the other three scenarios, which are NP-hard, it yields a better approximation factor than that of a naive tie-breaking method. Finally, we show inapproximability results for the above-mentioned three NP-hard scenarios
Moisture-triggered physically transient electronics
Physically transient electronics, a form of electronics that can physically disappear in a controllable manner, is very promising for emerging applications. Most of the transient processes reported so far only occur in aqueous solutions or biofluids, offering limited control over the triggering and degradation processes. We report novel moisture-triggered physically transient electronics, which exempt the needs of resorption solutions and can completely disappear within well-controlled time frames. The triggered transient process starts with the hydrolysis of the polyanhydride substrate in the presence of trace amounts of moisture in the air, a process that can generate products of corrosive organic acids to digest various inorganic electronic materials and components. Polyanhydride is the only example of polymer that undergoes surface erosion, a distinct feature that enables stable operation of the functional devices over a predefined time frame. Clear advantages of this novel triggered transience mode include that the lifetime of the devices can be precisely controlled by varying the moisture levels and changing the composition of the polymer substrate. The transience time scale can be tuned from days to weeks. Various transient devices, ranging from passive electronics (such as antenna, resistor, and capacitor) to active electronics ( such as transistor, diodes, optoelectronics, and memories), and an integrated system as a platform demonstration have been developed to illustrate the concept and verify the feasibility of this design strategy
Electron transport properties in magnetic tunnel junctions with epitaxial NiFe (111) ferromagnetic bottom electrodes
科研費報告書収録論文(課題番号:13305001・基盤研究(A)(2) ・H13~H15/研究代表者:宮崎, 照宣/高品位微小トンネル接合へのスピン注入
Effect of Ti seed layer on the magnetization reversal process of Co/NiFe/Al-oxide/NiFe junction films
科研費報告書収録論文(課題番号:13305001・基盤研究(A)(2) ・H13~H15/研究代表者:宮崎, 照宣/高品位微小トンネル接合へのスピン注入
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