Bifurcation diagrams in estimated parameter space using a pruned extreme learning machine.

We propose an algorithm to estimate parameter spaces by using a pruned extreme learning machine, but without using principal component analysis, and we plot bifurcation diagrams in the estimated parameter spaces to visualize changes in system patterns. The estimation of parameter spaces can predict changes in the behavior of a system when its parameters are changed. It can be very helpful to adjust the optimal parameters of unknown systems. In this paper, we estimate the dimension of parameter spaces using the singular values of trained synaptic weights and the parameter spaces based on the method proposed by Bagarinao et al., using a pruned extreme learning machine. We motivate this use of a pruned extreme learning machine through numerical experiments, with the estimation of the dimension of parameter spaces for various systems, and we show that the proposed method can successfully plot bifurcation diagrams in the estimated parameter spaces. In addition, we show the results of a bifurcation diagram in the estimated parameter space for maps that are nonlinear-in-parameters, since Bagarinao et al. limited their method to linear-in-parameters maps. In particular, we estimate the parameter spaces for a mathematical model of induction motor drives and for a model of vegetation biomass in ecosystems, which are both nonlinear-in-parameter maps corresponding to real-world systems.

Development of a superconducting bulk magnet for NMR and MRI.

A superconducting bulk magnet composed of six vertically stacked annular single-domain c-axis-oriented Eu-Ba-Cu-O crystals was energized to 4.74 T using a conventional superconducting magnet for high-resolution NMR spectroscopy. Shim coils, gradient coils, and radio frequency coils for high resolution NMR and MRI were installed in the 23 mm-diameter room-temperature bore of the bulk magnet. A 6.9 ppm peak-to-peak homogeneous region suitable for MRI was achieved in the central cylindrical region (6.2 mm diameter, 9.1 mm length) of the bulk magnet by using a single layer shim coil. A 21 Hz spectral resolution that can be used for high resolution NMR spectroscopy was obtained in the central cylindrical region (1.3 mm diameter, 4 mm length) of the bulk magnet by using a multichannel shim coil. A clear 3D MR image dataset of a chemically fixed mouse fetus with (50 µm)(3) voxel resolution was obtained in 5.5 h. We therefore concluded that the cryogen-free superconducting bulk magnet developed in this study is useful for high-resolution desktop NMR, MRI and mobile NMR device.

Simultaneously disrupting AtPrx2, AtPrx25 and AtPrx71 alters lignin content and structure in Arabidopsis stem.

Plant class III heme peroxidases catalyze lignin polymerization. Previous reports have shown that at least three Arabidopsis thaliana peroxidases, AtPrx2, AtPrx25 and AtPrx71, are involved in stem lignification using T-DNA insertion mutants, atprx2, atprx25, and atprx71. Here, we generated three double mutants, atprx2/atprx25, atprx2/atprx71, and atprx25/atprx71, and investigated the impact of the simultaneous deficiency of these peroxidases on lignins and plant growth. Stem tissue analysis using the acetyl bromide method and derivatization followed by reductive cleavage revealed improved lignin characteristics, such as lowered lignin content and increased arylglycerol-ß-aryl (ß-O-4) linkage type, especially ß-O-4 linked syringyl units, in lignin, supporting the roles of these genes in lignin polymerization. In addition, none of the double mutants exhibited severe growth defects, such as shorter plant stature, dwarfing, or sterility, and their stems had improved cell wall degradability. This study will contribute to progress in lignin bioengineering to improve lignocellulosic biomass.

Identification of Tyr74 and Tyr177 as substrate oxidation sites in cationic cell wall-bound peroxidase from Populus alba L.

Cationic cell wall-bound peroxidase (CWPO-C) has the capability to oxidize sinapyl alcohol, ferrocytochrome c, and synthetic lignin polymers, unlike most peroxidases that have been characterized in flowering plants, such as horseradish peroxidase and Arabidopsis thaliana peroxidase A2. It has been suggested that the oxidation site is located on the CWPO-C surface, and homology modeling and chemically modified CWPO-C studies suggest that Tyr74 and/or Tyr177 are possible participants in the catalytic site. The present study clarifies the importance of these Tyr residues for substrate oxidation, using recombinant CWPO-C and recombinant mutant CWPO-C with phenylalanine substitution(s) for tyrosine. Such recombinant proteins, produced in Escherichia coli as inclusion bodies, were successfully refolded to yield the active form, and purified recombinant protein solutions exhibited typical spectra of high-spin ferric protein and displayed H(2) O(2) -dependent oxidation of guaiacol, 2,6-dimethoxyphenol, and syringaldazine. Measurement of peroxidase activity with these guaiacyl and syringyl compounds as reducing substrates indicated that a single mutation, Y74F or Y177F, resulted in substantial loss of oxidation activity (∼ 40-60% and 82%, respectively). Also, over 95% of the oxidation activity was lost with a double mutation, Y74F/Y177F. These results indicated that Tyr74 and Tyr177, rather than the heme pocket, play a central role in the oxidation of these substrates. This is the first report of active residues on an enzyme surface being identified in a plant peroxidase. This study also suggests that sinapyl alcohol incorporation into lignin is performed by a peroxidase that generates Tyr radicals on its surface.

Evaluation of sleeve segmentectomy for early hilar lung cancer.

Roentgenographically occult lung cancers (ROLCs) are rare but are usually curable if they are properly diagnosed and treated. Between 1977 and 2000, we treated 51 patients with early hilar lung cancer (as defined by the Japan Lung Cancer Society) of ROLC form. If the occurrence of cancer is confined to segmental bronchi, we preserve the lung tissue as far as possible by using a sleeve segmentectomy. Eight of the 51 patients underwent sleeve segmentectomy. All 8 of these patients were men who were heavy smokers and had a mean age of 64.9 years (range, 59-74 years). The cancerous locations were R-B6 in 4 patients, L-B(1+2+3) in 2 patients, L-B(4+5) in 1 patient, and L-B6 in 1 patient. Two patients had double cancers (synchronous in one case and metachronous in the other). All 8 of the patients had squamous cell carcinoma, 3 of whose lesions were carcinoma in situ. The segments resected were R-S(6) in 3 patients, L-S(1+2+3) in 2 patients, L-S(4+5) in 1 patient, L-S(6) in 1 patient, and R-S6 combined with the middle lobe in 1 patient. There were no cases of morbidity or mortality. However, 1 patient who had undergone a left lower lobectomy for synchronous advanced squamous cell carcinoma 4 months before R-S(6) sleeve segmentectomy for contralateral early hilar lung cancer died of recurrence in the mediastinal lymph nodes 63 months after the first operation. Two patients died of other causes: one of pneumonia 61 months after L-S(4+5) sleeve segmentectomy and the other of myelopathy 36 months after L-S(1+2+3) sleeve segmentectomy. The remaining 5 patients are alive and well 178, 121, 109, 94, and 14 months after surgery. Sleeve segmentectomy is a curative operation for early stage squamous cell carcinoma of the segmental bronchus that preserves pulmonary function and should be used to treat patients carefully selected for the correct indications.