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Nishi-Tokyo-shi, Japan

Hagiwara K.,Keio University | Nakata M.,Keio University | Koyama Y.,Otsuma Womens University | Sato T.,Keio University
Biomaterials | Year: 2012

pDNA/chitosan complexes have been investigated as promising non-viral vectors for gene delivery. However, an increase in transfection efficiency and enhancement of physicochemical stability are required for their practical use. In this study, chondroitin sulfate (CS) was employed as a coating agent to increase the stability and transfection efficiency of a pDNA/chitosan complex. The pDNA/chitosan/CS ternary complexes formed with six kinds of CSs having different limiting viscosities (0.2-1.6) and sulfation degrees (5.0-7.0%) showed considerable differences in particle size, surface charge, and morphology. Among them, CS having a medium limiting viscosity (0.5-0.6) and a high sulfation degree (6.9%) showed significant enhancements in cell transfection efficiency. Analyses of cellular uptake and intracellular trafficking revealed that increased cellular uptake via macropinocytosis, together with reduced entry into lysosomes, may explain the promotion of transfection efficiency of ternary complexes. © 2012 Elsevier Ltd. Source


Ito T.,Musashino University | Koyama Y.,Otsuma Womens University | Otsuka M.,Musashino University
Journal of Pharmaceutical and Biomedical Analysis | Year: 2010

We have developed a new type of ternary gene transfection system comprising plasmid, polyethyleneimine, and hyaluronic acid (HA). HA recharged the positively charged DNA complexes into negative, and diminished the adverse interactions with bio-components. HA also improved the transcription efficiency, stabilized the dispersion, and protected the particles against lyophilizing induced inactivation. It enabled the preparation of very small complex particles, which showed high in vivo gene expression. In spite of the many attractive properties of the ternary complex systems, their detailed structure is still not clear. In this study, surface structures of the complexes were analyzed by non-confocal laser Raman microscopy. The correlation between the ζ-potential and the Raman spectrum is discussed. The DNA complex that showed the highest gene-expression level was prepared at the mixing ratio of COOH/NH = 0.5. At this ratio, all the amino groups were just protonated, and the surface was completely covered by HA attributed to the reduced nonspecific interaction of the complex in which all the amino groups have already interacted with carboxyls of HA, but not too much HA on the surface taken up by the cells. © 2009 Elsevier B.V. All rights reserved. Source


Kinjo H.,Otsuma Womens University
International Journal of Aging and Human Development | Year: 2010

Although much literature suggests that the age-related decline in episodic memory could be due to difficulties in binding features of information, previous studies focused mainly on memory of paired associations rather than memory of multiple bound features. In reality, however, there are many situations that require binding multiple features together simultaneously. Thus, this three-part experimental study using a working memory task examined two fundamental questions: whether and how well older adults perform a working memory task that requires them to bind three features together (Experiment 1), and whether and how much older adults' memory of units of three bound features could be improved by self-paced encoding and 3 weeks practice (Experiments 2 & 3). The results indicated that although older adults performed as well as young adults in remembering one unit of three features, they showed a deficit in remembering two units, making more severe errors than young adults, and the difference between the two age groups increased when remembering three units. However, older adults improved their memory performance substantially by two means: self-paced encoding and practice. The former primarily shortened reaction times while the latter primarily improved memory accuracy. With self-paced encoding, older adults were also capable of binding at least three units during encoding. Thus, it is possible to assume that under an optimal encoding period, the age-related deficits occur probably not at encoding but at retention and/or retrieval. Source


Yoda Y.,Hyogo College of Medicine | Otani N.,Hyogo College of Medicine | Sakurai S.,Otsuma Womens University | Shima M.,Hyogo College of Medicine
Journal of Epidemiology | Year: 2014

Exposure to air pollution has been reported to be associated with asthma exacerbation. However, little is known about the effects of air pollutant exposure in healthy people. A panel study was conducted to evaluate the acute effects of air pollutants on pulmonary function and airway inflammation in healthy subjects. Exhaled breath condensate (EBC) pH, fractional concentration of exhaled nitric oxide (FeNO), and pulmonary function were measured in 21 healthy young women repeatedly for two weeks in the summer in Tokyo, Japan. The concentrations of air pollutants were obtained from the monitoring stations in the neighborhoods where the subjects lived. Statistical analyses were performed using generalized estimating equations. Results: EBC pH decreased significantly with a 10-ppb increase in the 4-day average ozone (O3) concentration and a 10-μg/m3 increase in the 4-day average suspended particulate matter (SPM) concentration (-0.07 [95% confidence interval {CI} -0.11 to -0.03] and -0.08 [95% CI -0.12 to -0.03], respectively). Subjects with a history of rhinitis showed marked decreases in EBC pH associated with increases in O3 and SPM. The changes in forced expiratory volume in 1 second (FEV1) were also significantly associated with a 10-μg/m3 increase in the 3-day average concentration of SPM (-0.09 L [95% CI -0.17 to -0.01]). FeNO increased significantly in relation to the increase in O3 and SPM among only subjects with a history of asthma. Over the course of the study, EBC became significantly acidic with increases in O3 and SPM concentrations. Furthermore, higher SPM concentrations were associated with decreased FEV1. Subjects with a history of rhinitis or asthma are considered to be more susceptible to air pollutants. © 2014 Yoshiko Yoda et al. Source


Nacher J.C.,Toho University | Nacher J.C.,Future University Hakodate | Ochiai T.,Otsuma Womens University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

Increasingly accessible financial data allow researchers to infer market-dynamics-based laws and to propose models that are able to reproduce them. In recent years, several stylized facts have been uncovered. Here we perform an extensive analysis of foreign exchange data that leads to the unveiling of a statistical financial law. First, our findings show that, on average, volatility increases more when the price exceeds the highest (or lowest) value, i.e., breaks the resistance line. We call this the breaking-acceleration effect. Second, our results show that the probability P(T) to break the resistance line in the past time T follows power law in both real data and theoretically simulated data. However, the probability calculated using real data is rather lower than the one obtained using a traditional Black-Scholes (BS) model. Taken together, the present analysis characterizes a different stylized fact of financial markets and shows that the market exceeds a past (historical) extreme price fewer times than expected by the BS model (the resistance effect). However, when the market does, we predict that the average volatility at that time point will be much higher. These findings indicate that any Markovian model does not faithfully capture the market dynamics. © 2012 American Physical Society. Source

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