Progressive evolution model using a hardware evolution system

A progressive evolution model is proposed in which evolution takes place stepwise to match environmental changes. This model was designed to accelerate evolution. Environmental complexity is defined, and the problem environment progresses in environmental complexity gradually from easy to difficult. A verification system for the model is constructed on a hardware evolution system called AdAM (adaptive architecture methodology) in which each individual circuit takes parallel input sequences and operates on this input. A measure that is suitable for such parallel simultaneous operations schemes is designed to express environmental complexity. Simulations using an artificial ant problem (a modified John Muir trail) show that in the progressive evolution model, circuits can easily evolve complex behaviors. This work was presented, in part, at the Second International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20, 1997     

New functionalities in abundant element oxides: ubiquitous element strategy

While most ceramics are composed of ubiquitous elements (the ten most abundant elements within the Earth''s crust), many advanced materials are based on rare elements. A ‘rare-element crisis’ is approaching owing to the imbalance between the limited supply of rare elements and the increasing demand. Therefore, we propose a ‘ubiquitous element strategy’ for materials research, which aims to apply abundant elements in a variety of innovative applications. Creation of innovative oxide materials and devices based on conventional ceramics is one specific challenge. This review describes the concept of ubiquitous element strategy and gives some highlights of our recent research on the synthesis of electronic, thermionic and structural materials using ubiquitous elements.     

Shunt current and excess temperature sensitivity of Ith and ?ex in 1.3 ?m InGaAsP DH lasers

Shunt current flowing through p-n-p-n current blocking layers is examined as a possible cause of excess temperature sensitivity of Ith and ?ex which is often observed in InGaAsP BC and BH lasers. Under certain conditions, the shunt current reduces the T0 value of Ith from 65 K to 45 K and that of ?ex from 130 K to 40 K.     

A photoinduced electron-transfer reagent for peroxyacetic acid, 4-ethylthioacetylamino-7-phenylsulfonyl-2,1,3-benzoxadiazole,based on the method for predicting the fluorescence quantum yields

To develop new photoinduced electron-transfer (PET) reagents, we established a method for predicting the fluorescence quantum yields (phi) of the benzofurazan compounds bearing an aliphatic substituent group having an n-electron. The PET process occurred sufficiently to reduce the phi values in the benzofurazan compounds bearing an aliphatic moiety, which had a high quenching ability. The quenching ability was estimated by the molecular orbital calculation and Stern-Volmer plotting. The phi values of the benzofurazan compounds could be controlled by changing the quenching ability of a substituent group. We succeeded in designing a PET reagent for peroxyacetic acid (PAA), 4-ethylthioacetylamino-7-phenylsulfonyl-2,1,3-benzoxadiazole (EPB), using the established method for predicting the phi values. EPB and its oxidized derivative were separated by reversed-phase HPLC and fluorometrically detected at 479 nm with excitation at 362 nm. The attained detection limit for PAA was 105 fmol (S/N = 3) and the cross-reactivity toward hydrogen peroxide was very low, indicating EPB is a highly sensitive and selective reagent for PAA.     

Ten-thousand-hour operation of crank transverse-junction-stripe lasers grown by metal-organic chemical vapor deposition

For over 10 000 h, crank transverse-junction-stripe (TJS) laser diodes, grown by metal-organic chemical vapor deposition (MOCVD) maintain low and quite stable operating currents in the automatic-power-control aging with output power of 5 mW/facet at 55°C and 70°C. These MO-CVD lasers have excellent initial characteristics and small distributions of the characteristics. The reason for this excellent result is discussed in relation to the crystalline quality and the uniform growth of MO-CVD wafers.     

Robust estimation of BRDF model parameters

The effect of the Bidirectional Reflectance Distribution Function (BRDF) is one of the most important factors in correcting the reflectance obtained from remotely sensed data. Estimation of BRDF model parameters can be deteriorated by various factors; contamination of the observations by undetected subresolution clouds or snow patches, inconsistent atmospheric correction in multiangular time series due to uncertainties in the atmospheric parameters, slight variations of the surface condition during a period of observation, for example due to soil moisture changes, diurnal effects on vegetation structure, and geolocation errors [Lucht and Roujean, 2000]. In the present paper, parameter estimation robustness is examined using Bidirectional Reflectance Factor (BRF) data measured for paddy fields in Japan. We compare both the M-estimator and the least median of squares (LMedS) methods for robust parameter estimation to the ordinary least squares method (LSM). In experiments, simulated data that were produced by adding noises to the data measured on the ground surface were used. Experimental results demonstrate that if a robust estimation is sought, the LMedS method can be adopted for the robust estimation of a BRDF model parameter.     

Phased array of AlGaAs multistripe index-guided lasers

The fabrication and characteristics of a novel index-guided phase-locked array are described. A single-lobe far-field pattern was obtained up to the CW output of 100 mW in the 3-element diode laser.     

On mixed-level real-time hardware evolutionary systems

A new hardware model is proposed to allow synchronous sequential circuits to evolve their behavior systematically for a prespecified objective. The proposed model is highly modularized, so that a subcircuit of a selected circuit can serve as a building block for superior circuits. The model has generality in the sense that any circuit of this class can be emulated using this model. In addition, the implementation of the model has a regular structure, so that circuits can be reconfigured very quickly through a genetic operation. This work was presented, in part, at the Third International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–21, 1998     

Complexation of cobalt ion with copolypeptide containing tryptophan treated with nitric acid

Summary Tryptophan within copoly(N-hydroxyethyl L-glutamine-co-L-tryptophan) treated with nitric acid (EGT-N) dissociates negatively above pH 10.5 by the electron-attractive effect of nitro groups introduced into the indole ring. The interaction between EGT-N and various metal ions was investigated using UV/VIS, ESCA, and ICP measurement. EGT-N was found to selectively form a complex with cobalt ions above pH 10.5. The formation of the cobalt ion complex of EGT-N was confirmed to be caused by the cooperative coordination of the tryptophan-introduced nitro groups and the OH groups of hydroxyethyl L-glutamine. Received: 12 January 1998/Revised version: 6 March 1998/Accepted: 9 March 1998     

Antiandrogenic Effects of a Polyphenol in Carex kobomugi through Inhibition of Androgen Synthetic Pathway and Downregulation of Androgen Receptor in Prostate Cancer Cell Lines

Prostate cancer (PC) represents the most common cancer disease in men. Since high levels of androgens increase the risk of PC, androgen deprivation therapy is the primary treatment; however this leads to castration-resistant PC (CRPC) with a poor prognosis. The progression to CRPC involves ectopic androgen production in the adrenal glands and abnormal activation of androgen signaling due to mutations and/or amplification of the androgen receptor (AR) as well as activation of androgen-independent proliferative pathways. Recent studies have shown that adrenal-derived 11-oxygenated androgens (11-ketotestosterone and 11-ketodihydrotestosterone) with potencies equivalent to those of traditional androgens (testosterone and dihydrotestosterone) are biomarkers of CRPC. Additionally, dehydrogenase/reductase SDR family member 11 (DHRS11) has been reported to be a 17β-hydroxysteroid dehydrogenase that catalyzes the production of the 11-oxygenated and traditional androgens. This study was conducted to evaluate the pathophysiological roles of DHRS11 in PC using three LNCaP, C4-2 and 22Rv1 cell lines. DHRS11 silencing and inhibition resulted in suppression of the androgen-induced expression of AR downstream genes and decreases in the expression of nuclear AR and the proliferation marker Ki67, suggesting that DHRS11 is involved in androgen-dependent PC cell proliferation. We found that 5,7-dihydroxy-8-methyl-2-[2-(4-hydroxyphenyl)ethenyl]-4H-1-benzopyran-4-one (Kobochromone A, KC-A), an ingredient in the flowers of Carex kobomugi, is a novel potent DHRS11 inhibitor (IC₅₀ = 0.35 μM). Additionally, KC-A itself decreased the AR expression in PC cells. Therefore, KC-A suppresses the androgen signaling in PC cells through both DHRS11 inhibition and AR downregulation. Furthermore, KC-A enhanced the anticancer activity of abiraterone, a CRPC drug, suggesting that it may be a potential candidate for the development of drugs for the prevention and treatment of CRPC.