Photoinduced bidirectional phase transitions in single crystals of polydiacetylenes

Photoinduced phase transitions have been observed between the two phases in single crystals of polydiacetylenes with side-groups of alkylurethanes. The threshold of the excitation intensity for the photochromism is extremely low, one absorbed photon per 140 repeated backbone units, indicating a collective nature of the photoconversion. The excitation spectra for the converted fraction clearly show that the photoinduced phase transition is mediated by photogeneration of polaronic species and not of singlet excitons.     

A Tuning Circuit with Two Half-Wave Distributed Junctions for All-NbN SIS Mixers

A novel broadband tuning circuit composed of two low-current-density half-wave NbN/MgO/NbN tunnel junctions connected by a half-wave NbN/MgO/NbN microstrip line has been successfully tested in a quasi-optical mixer at frequencies above 700 GHz. The circuit had a designed center frequency of 870 GHz, was integrated in a center-fed twin-slot antenna, and was fed via a quarter-wave impedance transformer. Heterodyne measurments showed double-side-band receiver noise temperatures equivalent to 6-9 quanta from 675 to 810 GHz for a mixer with a current density of 6.7 kA/cm². The RF bandwidth was broader than that of a conventional mixer using a full-wave junction with the same current density.     

The cause of the uneven carbonization process in wet coal charging in coke oven chamber

In the case of the wet coal charging process in coke oven chamber, it is known that the coking process is uneven and a local carbonization delay occurs. The reason was investigated through a laboratory-scale experiment and a quantitative estimation. A partial carbonization test in a test coke oven replicated the uneven plastic layer and local carbonization delay. It was revealed that most of the gas generated in the uncarbonized coal layer results from the evaporation of condensed water and that steam can break through the plastic layer in a test coke oven. Moreover, the order estimation implied that steam that generates in the uncarbonized coal layer and breaks through the plastic layer has sufficient heat capacity to cool the heating wall and delay the carbonization. It was also shown that the steam pressure peak measured in a commercial coke oven is much lower than the estimated steam pressure in this study assuming steam not breaking through the plastic layer. The above-mentioned results and quantitative investigation strongly support the ‘steam breaking through the plastic layer’ theory proposed by Dr. Rohde that an uneven carbonization process is caused by vaporized coal moisture breaking through the plastic layer at definite, unforeseeable points, which results in cooling of the wall by the steam flow.     

2D artificial life system using network-type assembly-like language: influence of change in environment with costs of instructions

To unlock the full potential of evolution in digital media, a Tierra-like system using network-type assembly-like language has been constructed. In the system, like Avida, digital creatures, self-replicating programs, live in a discrete 2D torus space and an interaction between creatures is restricted locally. Bearing a genetic network in mind, network structure is introduced. In the previous works, it is shown that the possibility that the network-type model has more potential of evolution than a linear-type model like Avida in a simple environment. In this paper, to study the potential of evolution more precisely, we model the effects of environment other than creatures. As one of the simplest models of such environment, the cost of execution, i.e. executing time, is introduced. The difficult environment to live in costs high to execute instructions, the easy environment does low. In computer experiments, we have investigated the influence of change in environment by analyzing the process of evolution and diversity of the system. Experimental results show that the network-type system keeps more stable diversity than the linear-type system does, even when the environment changes drastically. This indicates the possibility that the network-type system has more potential of evolution than the linear-type system has. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Ideal crosslinked-polymers and their characterization in free-radical monovinyl-divinyl copolymerizations

The critical conditions in which the classical Flory-Stockmayer gelation theory (F-S theory) is applicable to monovinyl-divinyl copolymerizations were pursued in detail. The resulting prepolymers or precursors of ideal crosslinked-polymers were characterized as standard polymers for the discussion of network formation in free-radical monovinyl-divinyl copolymerizations. Methyl methacrylate was copolymerized with a small amount of ethylene dimethacrylate, butylene dimethacrylate or nonapropyleneglycol dimethacrylate in the presence of lauryl mercaptan, a chain transfer agent to reduce the occurrence of a thermodynamic excluded volume effect and intramolecular crosslinking as the primary and secondary factors, respectively, for the greatly delayed gelation in the free-radical monovinyl-divinyl copolymerizations and, moreover, to keep the primary chain length constant by inhibiting a gel effect. The ratio of the actual gel point to the theoretical one reached 1.1, supporting the validity of F-S theory. The resulting prepolymers were subjected to SEC-MALLS analysis to determine the molecular weights, the molecular-weight distributions and the radii of gyration; the correlations of molecular weight vs. elution volume and radius of gyration vs. molecular weight were useful for the characterization of the precursors of ideal network-polymers.     

Theory of rough surface effects on the anisotropic BCS states

We present a Green's function theory of the rough surface effects on the anisotropic BCS states using the formulation developed in the randomly rippled wall model. It is shown that the randomly rippled wall formulation is general enough to treat rough surface effects from the specular limit to the diffusive limit. We propose a statistical wall configuration such that gives the diffusive limit in the normal state. Within the weak coupling theory, we give a formal solution of the quasi-classical Green's function in a slab geometry and in a semi-infinite geometry with arbitrarily rough surfaces. The formal solution already satisfies the boundary condition. In the diffusive limit, the present theory correctly recovers the linearized gap equation obtained by Kjäldman et al. for the p-wave state in a slab geometry.     

Case report of miliary TB, with mediastinal TB involving the aorta, trachea and esophagus with death due to hemorrhage from perforation of aorta into the esophagus during treatment

A 32-year-old male was diagnosed as having miliary tuberculosis in May 1990. In spite of antituberculosis chemotherapy, he developed tuberculous meningitis and intracranial tuberculoma in September 1990. Miliary shadows on chest X-ray disappeared in December 1990. However, he developed left atelectasis, and bronchofiberscopy revealed soft tumor in the left main bronchus in January 1991. He suddenly vomited large amounts of blood and expired in February 1991. At autopsy, tuberculous lymphadenitis and cavitation were noted in the mediastinum, through which the left main bronchus, esophagus and descending aorta communicated. The patient died of massive bleeding which resulted from the rupture of tuberculous aortitis into the esophagus. This is a very rare case of tuberculous aortic aneurysm rupturing into both the bronchus and esophagus.     

Antitumor activity of 1 M tegafur-0.4 M 5-chloro-2,4-dihydroxypyridine-1 M potassium oxonate (S-1) against human colon carcinoma orthotopically implanted into nude rats

The purpose of this study was to establish a nude rat orthotopic (organ-specific) human colorectal cancer model as an in vivo secondary screen for general evaluation of new anticancer agents against colorectal cancer and to evaluate practically the antitumor activity of 1 M tegafur-0.4 M 5-chloro-2,4-dihydroxypyridine-1 M potassium oxonate (S-1), a new p.o. fluoropyrimidine, in comparison to 1 M tegafur-4 M uracil [(UFT) effective on colorectal tumor in clinical]. After implantation of KM12C, a human colorectal cancer cell line, into the subserosal layer of the colon as a single-cell suspension, extensive local tumor growth and invasion to both the mucosal and the serosal sides were observed in all rats. Metastatic foci were also formed in both lymph nodes and lungs following local tumor growth in all of them. Using this method, an equitoxic dose of S-1 (15 mg/kg/day) and UFT (30 mg/kg/day) was administered p.o. for 14 consecutive days from 7 days after tumor cell implantation. S-1 showed a higher tumor growth inhibition than UFT did [S-1, 57% (significantly different from the tumor weight of the untreated group at P < 0.05) and UFT, 18% (P > 0.05)]. When both drugs were administered to nude rats bearing KM12C injected into the cecal wall for 28 consecutive days at equitoxic doses, the mean survival in the S-1 group was 16 days longer than that in the untreated group (P < 0.01) but that in the UFT group was only 8 days longer (P > 0.05). After the administration of an equitoxic dose of both drugs, S-1 gave the higher levels than UFT in various pharmacokinetic parameters as follows: area under the curve 0-24 h of 5-fluorouracil in plasma (3.5-fold), area under the curve 0-24 h of 5-fluorouracil incorporated into RNA in the tumor (1.3-fold), and thymidylate synthase inhibition rate (percentage) in the tumor (about 20%). Collectively, these findings suggested that this orthotopic human colorectal tumor model in nude rats is useful to evaluate the clinical therapeutic efficacy of drugs or therapies for colorectal cancer, and that S-1 had a higher therapeutic effect on human colorectal tumor than UFT did.