Skeletal muscle pathology in systemic sclerosis

OBJECTIVE: Systemic sclerosis (SSc) is characterized by abnormal deposition of collagen in the skin and by visceral involvement. Muscle weakness is a relatively frequent complication of SSc, although severity varies. We studied muscle pathology in patients with SSc with progressive muscle involvement. METHODS: We performed histochemical and immunohistochemical investigations to detect neural cell adhesion molecule (NCAM). RESULTS: Five of the 6 cases of SSc expressed NCAM in atrophic angulated fibers (some fibers stained heavily with oxidative enzymes). CONCLUSION: Neurogenic involvement in SSc is more frequent than reported.     

Imaging of large early and early advanced hepatocellular carcinomas of more than 5 cm in diameter: report of two cases

In an attempt to clarify the imaging characteristics of large early and early advanced hepatocellular carcinoma (HCC), we present two such cases which were greater than 5 cm in diameter. One case had four early HCCs and the other had early advanced HCC which was followed for five years and nine months. Multiphasic CT, CT arteriography (CTA), CT arterial portography (CTAP), and MR imaging were performed. Early HCC was shown as a low density mass by multiphasic contrast CT, CTAP and as a hyperintense mass on a T1-weighted image (WI) and isointense on T2WI. Early advanced HCC was demonstrated as a hypodense mass with hyperenhancing interior nodules on CTA, and isodense with hypodense internal foci on CTAP. One follow-up case showed a multi-step progression from early to early advanced HCC, and finally to overtly advanced HCC. Despite the unusually large size of these two tumors, the findings of multiphasic CT, CTA, CTAP, and MR imaging were consistent with those seen in common-sized (less than 2 cm) early and early advanced HCCs. Multi-step progression of hepatocarcinogenesis was observed in one case.     

Potent preventive action of alpha-carotene against carcinogenesis: spontaneous liver carcinogenesis and promoting stage of lung and skin carcinogenesis in mice are suppressed more effectively by alpha-carotene than by beta-carotene

Although beta-carotene has been considered to be a key cancer preventive agent in green and yellow vegetables, other types of carotenoids, such as alpha-carotene, may also contribute to anticarcinogenic action, since these carotenoids usually coexist with beta-carotene and are detectable in human blood and tissues. In this study, we compared the inhibitory effect of natural alpha-carotene, obtained from palm oil, with that of beta-carotene on spontaneous liver carcinogenesis in C3H/He male mice. The mean number of hepatomas per mouse was significantly decreased by alpha-carotene supplementation (per os administration in drinking water at a concentration of 0.05%, ad libitum) as compared with that in the control group (P < 0.001, Student's t test). On the other hand, beta-carotene, at the same dose as alpha-carotene, did not show any such significant difference from the control group. Furthermore, we also compared the antitumor-promoting activity of alpha-carotene with that of beta-carotene against two-stage mouse lung carcinogenesis (initiator, 4-nitroquinoline 1-oxide; promoter, glycerol). alpha-Carotene, but not beta-carotene, reduced the number of lung tumors per mouse to about 30% of that in the control group (P < 0.001, Student's t test). The higher potency of the antitumor-promoting action of alpha-carotene compared to beta-carotene was confirmed in other experimental systems; e.g., alpha-carotene was also found to have a stronger effect than beta-carotene in suppressing the promoting activity of 12-O-tetradecanoylphorbol-13-acetate on skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated mice. These results suggest that not only beta-carotene, but also other types of carotenoids, such as alpha-carotene, may play an important role in cancer prevention.     

Contacts and Coordination Numbers in a Compact of Polyhedral Particles

Model experiments were carried out with plastic polyhedra (cuboctahedra, in particular) contained in a beaker. The packing structures of these polyhedra were characterized in terms of three different types of contacts-point, line, and face contacts-along with the coordination numbers, n _c. The present data indicate that the numerical distribution of n _c shifted to larger values of n _c with increasing distance from the beaker wall. On the other hand, the fractional values with respect to each specific type of contact, n _p/( n _p+ n _I+ n _f), n _I/( n _p+ n _I+ n _f), and n _f/( n _p+ n _I+ n _f), changed little with location, except at the beaker wall. The small changes of these fractional values were explained with ignorance of the numerical distribution of contact angles and also of the contact areas in counting the three kinds of contacts. The measured percentages of point, line, and face contacts in the central region ranged from 17% to 20%, 60% to 65%, and 15% to 23%, respectively. The larger percentage of line contacts is attributable to the cooperation of two tendencies inducing opposite orders, namely (1) the stability of a contact between polyhedra free from the array of polyhedra around it, which gives n _p < n _I < n _f and (2) the adaptability of a contact to an array of polyhedra around it, which gives n _f < n _I < n _p. The number of contacts with small contact angles was substantial in the case of the point and line contacts.     

Fabrication of Transparent Yttria Ceramics by the Low-Temperature Synthesis of Yttrium Hydroxide

Thin flakes of yttrium hydroxide agglomerated in a manner resembling houses of cards with aging at 10°C. The agglomerate then dissociated into fine yttria particles with calcination at >800°C. The particle size of the calcined powder increased appreciably as the calcination temperature increased. The shrinkage curve indicated similar densification behavior among undoped yttria powders calcined at 800°–1000°C, despite considerable particle growth as the calcination temperature increased. Increasing the calcination temperature to >1000°C shifted the shrinkage curve appreciably to the high-temperature region. Sulfate-ion-doped yttria particles had round edges, irrespective of calcination temperature, in contrast to the sharp edges of the undoped yttria particles. A calcination temperature of <1000°C resulted in skeleton yttria particles, which exhibited poor sinterability. At a calcination temperature >1000°C, the skeleton particles dissociated into monodispersed particles that densified easily. When the calcination temperature was >1000°C and the average particle sizes were similar, the undoped and sulfate-ion-doped yttria showed similar densification rates. The transparency of the sintered yttria ceramics was dependent on both the calcination temperature and sulfate-ion doping: that is, sulfate-ion doping and calcining at 1100°C were both necessary conditions for the fabrication of a transparent body.     

A proposition of adaptive state space partition in reinforcement learning with Voronoi tessellation

This paper presents a new adaptive segmentation of continuous state space based on vector quantization algorithm such as Linde–Buzo–Gray for high-dimensional continuous state spaces. The objective of adaptive state space partitioning is to develop the efficiency of learning reward values with an accumulation of state transition vector in a single-agent environment. We constructed our single-agent model in continuous state and discrete actions spaces using Q-learning function. Moreover, the study of the resulting state space partition reveals a Voronoi tessellation. In addition, the experimental results show that this proposed method can partition the continuous state space appropriately into Voronoi regions according to not only the number of actions, but also achieve a good performance of reward-based learning tasks compared with other approaches such as square partition lattice on discrete state space.     

Early-stage sintering in a powder compact of polyhedral particles II. Experimental analysis with a highly sinterable Al2O3

A model of early-stage sintering for polyhedral particles is examined with a highly sinterable Al₂O₃ powder. Combining of the initial and intermediate stages based on the model concerned describes quantitatively its sintering data such as power dependence of time and reduction in a specific surface area. Valid estimations of a model and/or mechanisms of sintering necessitate the accurate measurement of both shrinkage versus sintering time and specific surface area versus shrinkage.     

Propagation characteristics of a diffracted M2 beam

The propagation characteristics of a beam diffracted by a circular aperture are investigated. The beam-quality factor M2 defined by an 86.5% power-content radius is given theoretically and experimentally as a function of the truncation ratio. It is found that the theoretical limit of M2 is 2.37 times as great as that of an incident beam as the truncation ratio approaches 0. For a weakly diffracted beam a simple formula giving M2 is derived. Although M2 does not increase much with diffraction, the influence of diffraction should be taken into account in beam brightness.     

Reactive Ceria Nanopowders via Carbonate Precipitation

Nanocrystalline CeO₂ powders have been successfully synthesized via a carbonate precipitation method, using ammonium carbonate (AC) as the precipitant and cerium nitrate hexahydrate as the cerium source. The AC/Ce³⁺ molar ratio ( R ) affects significantly precursor properties, and spherical nanoparticles can be produced only in a narrow range of 2 < R ≤ 3. The precursor, having an approximate composition of Ce(OH)CO₃·2.5H₂O, decomposes to CeO₂ at temperatures ≥300°C. The CeO₂ powder calcined at 700°C exhibits high reactivity and can be densified to >99% of theoretical at 1000°C.     

10-mol%-Gd2O3-Doped CeO2 Solid Solutions via Carbonate Coprecipitation: A Comparative Study

10mol% Gd₂O₃-doped CeO₂ solid solutions (20GDC) have been synthesized via carbonate coprecipitation using ammonium bicarbonate (AHC) and urea as the precipitants. The precursors and the resultant oxide powders were characterized via chemical analysis, X-ray diffractometry (XRD), Brunauer–Emmett–Teller (BET) analysis, and high-resolution scanning electron microscopy (HRSEM). Sinterabilities of the 20GDC oxides in air were studied by constant-rate-of-heating (CRH) sintering and the conventional ramp-and-holding sintering methods. The precursor processed by both methods is hydroxyl carbonate but shows quite different particle morphologies in the two cases. Highly sinterable 20GDC oxides that can be densified to >99% of the theoretical at 1050°C within 4 h have been obtained via the AHC method.