A Quick Rendering Method Using Basis Functions for Interactive Lighting Design

When designing interior lighting effects, it is desirable to compare a variety of lighting designs involving different lighting devices and directions of light. It is, however, time-consuming to generate images with many different lighting parameters, taking interreflection into account, because all luminances must be calculated and recalculated. This makes it difficult to design lighting effects interactively. To address this problem, this paper proposes a method of quickly generating images of a given scene illustrating an interreflective environment illuminated by sources with arbitrary luminous intensity distributions. In the proposed method, the luminous intensity ditribution is expressed with basis functions. The proposed method uses a series of spherical harmonic functions as basis functions, and calculates in advance each intensity on surfaces lit by the light sources whose luminous intensity distribution are the same as the spherical harmonic functions. The proposed method makes it possible to generate images so quickly that we can change the luminous intensity distribution interactively. Combining the proposed method with an interactive walk-through that employs intensity mapping, an interactive system for lighting design is implemented. The usefulness of the proposed method is demonstrated by its application to interactive lighting design, where many images are generated by altering lighting devices and/or direction of light.     

9H-xanthene-2,7-diols as antioxidants for autoxidation of linoleic acid

The antioxidant activities of 9H-xanthene-2,7-diols and α-tocopherol were studied during the oxidation of linoleic acid in a homogeneous solution and in an aqueous micelle dispersion. The antioxidant activities of 9H-xanthene-2,7-diols for both systems were 1.0–2.4 times greater relative to α-tocopherol. In addition, the 1,3,4,5,6,8-hexamethylxanthene-2,7-diol showed less cytotoxicity toward human fibroblasts than did 2,6-di-t-butyl-4-methylphenol.     

Analysis on hopping mechanism of planetary robotic vehicle by microgravity experiments

For future exploration missions to small planetary bodies, in-situ surface observation by robots would be a promising method to investigate the target body whose surface gravity is very small. The authors have researched the mobility system under the microgravity environment and proposed a new mobile system which drives a robot by hopping. Due to the uncertainty of the escape velocity from the target small body, the hop velocity of the robot has to be controlled on-board. This paper proposes a velocity control method of the hopping mechanism, which was evaluated by microgravity experiments and compared with numerical simulation analyses.     

Analysis of carrier-blocking effect in AlGaAs/GaAs HBT's withinsulating external collector and design criteria for collector-up HBT's

Two-dimensional simulations of cutoff frequencies for AlGaAs/GaAs HBT's with perfectly insulating external collector are made, and the results are compared with those for a case with semi-insulating external collector and for a case with normal n^- external collector. It is found that in the case with perfectly insulating external collector, minority carriers injected into the base from the emitter are partially blocked by the insulating layer and accumulate in the external base region. These carriers increase the effective base delay time, resulting in remarkable degradation of the cutoff frequency. In relation to this effect, a collector-up HBT is also simulated, and the design criteria for it are discussed. It is concluded that the effective emitter width should be made narrower than the collector width     

Plausible guard effect on the active sites of heterogeneous Ziegler–Natta catalyst by coordinating monomers and growing polymer chains in the initial stage of propene polymerization

Investigation of propene polymerization by a modified stopped‐flow technique using TiCl₄/ethylbenzoate(EB)/MgCl₂ Ziegler–Natta catalyst with or without pretreating the catalyst with triethylaluminium (TEA) within an ultra‐short period (ca 1 s) was conducted to gain new understanding of the nature of active sites related to TEA in the early stage of polymerization. When the catalyst was pretreated by a cocatalyst, deactivation behaviour was clearly observed, even within an extremely short pretreatment period. In contrast, without pretreatment, the deactivation of active sites can be neglected within the polymerization period indicating that the activated Ti species might be protected from deactivation by TEA when monomer is present in the system. A plausible guard effect on the active sites by coordinating monomer and growing polymer chains in the initial stage of polymerization is proposed to account for this phenomenon. Copyright © 2004 Society of Chemical Industry     

Role of an extrinsic 33 kilodalton protein of photosystem II in the turnover of the reaction center-binding protein D1 during photoinhibition

The reaction center-binding protein D1 of photosystem II (PS II) undergoes rapid turnover under light stress conditions. In the present study, we investigated the role of the extrinsic 33 kDa protein (OEC33) in the early stages of D1 turnover. D1 degradation was measured after strong illumination (1000-5000 microE m-2 S-1) of spinach manganese-depleted, PSII-enriched membrane and core samples in the presence and absence of the OEC33 under aerobic conditions at room temperature. PSII samples lacking the OEC33 were prepared by standard biochemical treatments with Tris or CaCl2/NH2OH while samples retaining the OEC33 were prepared with NH2OH or NaCl/NH2OH. The degradation of D1, monitored by SDS/urea-polyacrylamide gel electrophoresis and Western blotting using specific antibodies against D1, proceeds to a greater extent in NH2OH-treated samples than in Tris-treated samples over a 60 min illumination period. Under the same conditions, significantly more aggregation of D1 occurs in the Tris-treated samples than in the NH2OH-treated samples. The lower level of D1 degradation in Tris-treated samples is not due to secondary proteolysis, as judged from the time course for degradation at 25 degrees C or the degradation pattern at 4 degrees C. Similarly, for NaCl/NH2OH-treated samples, D1 degradation is greater and D1 aggregation less than in CaCl2/NH2OH-treated samples. The effect of the presence of the OEC33 on D1 degradation and aggregation is confirmed by reconstitution experiments in which the isolated OEC33 is restored back to Tris-treated samples. During very strong illumination, significant loss of CP43 also occurs in Tris-treated but not in NH2OH-treated samples. Structural analysis of PS II core complexes by Fourier transform infrared (FT-IR) spectroscopy revealed very little change in the protein secondary structure after 10 min illumination of NH2OH-treated samples while a large 10% decrease of alpha-helix content occurs in Tris-treated samples. On the basis of these results, we suggest that either (1) the OEC33 stabilizes the structural integrity of PS II such that it prevents the photodamaged D1 protein from aggregating with nearby polypeptides and thereby facilitating degradation or (2) the OEC33 specifically stabilizes CP43, a putative D1-specific protease, which normally promotes the efficient degradation of D1.     

Recovery of cardiac function by long-term left ventricular support in patients with end-stage cardiomyopathy

Effects of long-term left ventricular (LV) support on end-stage cardiomyopathy patients is unclear. We applied our LV assist system (LVAS) to six heart transplant candidates, aged 17 to 49, with dilated cardiomyopathy, including one dilated phase hypertrophied cardiomyopathy. LVAS was installed between the left atrium and the ascending aorta, and the pump was positioned parecorporeally. In all patients, their general condition improved, and their pump flows were kept at 4 to 5 L/min. Exercise was started after stabilization of their general condition under constant pump flow. Natural heart size and function were examined by echocardiography. In the beginning of assist, all patients showed impaired cardiac function and LV dilation. During LV assist, systolic function measured by ejection time improved in all patients. Left ventricular end-diastolic dimension (LVDd), showed a remarkable decrease in two patients, who were weaned from LVAS after 3 months of support. They are doing well more than 1 year and 3 years after removal; peak VO2 levels (ml/min/kg) were 30 at 1.2 years and 27 at 2.7 years after removal. In the other four patients, however, LVDd had no remarkable changes, and three could not be weaned from LVAS. The last was discontinued from LVAS after 5 months of support because of infection and died 2 months after removal. From this experience, long-term LVAS may provide the chance for recovery of the natural heart in patients with end-stage cardiomyopathy. The patients whose hearts showed remodeling were able to be weaned from LVAS, and their heart function maintained in good condition for several years.