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Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide). Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc.) to implement a viable component for in-line fluidic sensor systems. [ABSTRACT FROM AUTHOR]

It has recently been determined that generating an explanatory hypothesis to explain a discrepant event is important for students’ conceptual change. The purpose of this study is to investigate how students generate new explanatory hypotheses. To achieve this goal, questions are used to identify students’ prior ideas related to electromagnetic induction. After showing conflicting phenomena, six college students are asked to suggest explanatory hypotheses to explain the phenomena. Using interviews, the processes of generating explanatory hypotheses are analyzed and three types of hypotheses suggested by students are subsequently identified: theoretical, experiential, and auxiliary hypotheses. In addition, models of generating each type of explanatory hypothesis are also suggested. It is concluded that subjects use similarity-based reasoning to relate their background knowledge or experiences with the conflicting phenomena to be explained. Background knowledge plays a very important role in generating new theoretical explanatory hypotheses. An example of a scientific inquiry activity for improving the skill of “generating scientific hypotheses” is also presented in this paper. [ABSTRACT FROM AUTHOR]

The relative preference for a target product over a competitor can be increased by providing a third alternative (a"decoy") that is clearly inferior to the target but is not necessarily inferior to the competitor. In 3 experiments, we examined the conditions in which these decoy effects occur. When participants reported their preferences immediately after being exposed to the information about them, the influence of decoys on preferences was attributable to the justification they provided for choosing the target over the competitor. (That is, a decoy had an impact if and only if the target was superior to the decoy but the competitor was not.) When participants evaluated each product individually before making their choices, however, they based their preferences on these evaluations. In this case, decoys exerted their influence through their impact on the values that participants assigned to the attributes on which the evaluations were based. This influence was evident even when the decoy was clearly inferior to both the target and competitor. Moreover, it occurred under conditions in which the target and competitor were in different product categories and also when the decoy was in a totally different product domain than the target and competitor. [ABSTRACT FROM AUTHOR]

Using a numerical hydrodynamics code, we perform various idealized galaxy merger simulations to study the star formation (SF) of two merging disk galaxies. Our simulations include gas accretion onto supermassive black holes and active galactic nucleus (AGN) feedback. By comparing AGN simulations with those without AGNs, we attempt to understand when the AGN feedback effect is significant. Using ∼70 simulations, we investigate SF with the AGN effect in mergers with a variety of mass ratios, inclinations, orbits, galaxy structures, and morphologies. Using these merger simulations with AGN feedback, we measure merger-driven SF using the burst efficiency parameter introduced by Cox et al. We confirm previous studies which demonstrated that, in galaxy mergers, AGN suppresses SF more efficiently than in isolated galaxies. However, we also find that the effect of AGNs on SF is larger in major than in minor mergers. In minor merger simulations with different primary bulge-to-total ratios, the effect of bulge fraction on the merger-driven SF decreases due to AGN feedback. We create models of Sa-, Sb-, and Sc-type galaxies and compare their SF properties while undergoing mergers. With the current AGN prescriptions, the difference in merger-driven SF is not as pronounced as in the recent observational study of Kaviraj. We discuss the implications of this discrepancy. [ABSTRACT FROM AUTHOR]

A novel design of a biped robot inspired by domestic cats for fast running is introduced. The skeletomuscular system of a cat is analysed and applied to determine the link parameters and the linkage structure of the proposed mechanism. The linkage design of the leg mechanism is explained and a kinematic analysis based on vector loop equations is performed. The effectiveness of the proposed mechanism is verified experimentally. The biped robot runs at an average speed of 2 m/s at a step frequency of 4 Hz. This leg mechanism can facilitate the development of fast running robot systems. [ABSTRACT FROM AUTHOR]

Van Dokkum and Conroy revisited the unexpectedly strong Na i lines at 8200 Å found in some giant elliptical galaxies and interpreted them as evidence for an unusually bottom-heavy initial mass function. Jeong et al. later found a large population of galaxies showing equally extraordinary Na D doublet absorption lines at 5900 Å (Na D excess objects: NEOs) and showed that their origins can be different for different types of galaxies. While a Na D excess seems to be related to the interstellar medium (ISM) in late-type galaxies, smooth-looking early-type NEOs show little or no dust extinction and hence no compelling signs of ISM contributions. To further test this finding, we measured the Doppler components in the Na D lines. We hypothesized that the ISM would have a better (albeit not definite) chance of showing a blueshift Doppler departure from the bulk of the stellar population due to outflow caused by either star formation or AGN activities. Many of the late-type NEOs clearly show blueshift in their Na D lines, which is consistent with the former interpretation that the Na D excess found in them is related to gas outflow caused by star formation. On the contrary, smooth-looking early-type NEOs do not show any notable Doppler components, which is also consistent with the interpretation of Jeong et al. that the Na D excess in early-type NEOs is likely not related to ISM activities but is purely stellar in origin. [ABSTRACT FROM AUTHOR]

The presence of glucose degradation products (GDPs) in peritoneal dialysis (PD) fluids has many adverse effects, namely clinically significant abdominal pain or discomfort during infusion, inhibition of cell proliferation, impairment of inflammatory cell function, cytotoxicity, and the induction of vascular endothelial growth factor (VEGF). In a prospective, randomized, controlled trial comparing a low GDP PD solution (pH 7.0, two compartment bag: low GDP) to conventional PD solution (pH 5.5: high GDP), the overnight dialysate levels of the markers of inflammation/wound healing (hyaluronic acid (HA)), mesothelial cell mass/membrane integrity (cancer antigen 125 (CA125)), and angiogenesis (VEGF) were assessed over a 12-month period. Twenty-six newly commencing continuous ambulatory peritoneal dialysis (CAPD) patients were randomly assigned to either the Low GDP group ( n = 16) or the High GDP group ( n = 10). Standard peritoneal permeability analysis for membrane transport characteristics and dialysis adequacy with nutritional status (serum albumin, nPCR) were evaluated at 1, 6, and 12 months. In patients treated with high GDP solution, there was significant increase in VEGF with time (time = 1 month, 67.2 ± 10.8; time = 6 months, 189.8 ± 90.2; and time = 12 months, 169.3 ± 83.1 pg/mg of protein; P < 0.05). There was no significant change of VEGF with time in the low GDP group. Significantly higher concentrations of CA125 (65.5 ± 10.4 vs. 19.7 ± 2.6 at 1 month, P < 0.0001; 66.6 ± 9.8 vs. 29.7 ± 5.0 at 6 months, P < 0.01; 68.7 ± 10.5 vs. 30.7 ± 10.0 U/mL at 12 months, P < 0.01) and lower concentrations of HA (114.6 ± 18.8 vs. 254.3 ± 69.2 at 1 month, P < 0.05; 417.5 ± 57.2 vs. 1277.5 ± 367.9 ng/mg of protein at 12 month, P < 0.05) were observed in the low GDP group compared with the high GDP group. In conclusion, continuous therapy with the low GDP solution modulates the levels of surrogate markers of peritoneal inflammation, integrity and angiogenesis. The results strongly suggest that the use of a low GDP solution would be beneficial to maintain the function and structural integrity of the peritoneal membrane. [ABSTRACT FROM AUTHOR]