Na+ channel block prevents the ischemia-induced release of norepinephrine from spinal cord slices

To assess the role of beta-phenylethylamine in aspects of dopamine release, we measured the level of beta-phenylethylamine in the rat striatum after killing the rats by microwave irradiation. We then investigated the effect of beta-phenylethylamine on electrically evoked dopamine release from rat striatal slices in vitro. The striatal beta-phenylethylamine level was 46.5 +/- 3.5 ng/g wet tissue, equivalent to 0.3 micromol/l. Superfusion with low concentrations of beta-phenylethylamine up to 1 micromol/l had no effect on spontaneous or electrically evoked dopamine release from striatal slices. Quinpirole reduced the evoked dopamine release from slices in a concentration-dependent manner. The quinpirole-induced reduction of evoked dopamine release was attenuated 30% by superfusion with 0.3 micromol/l beta-phenylethylamine. Moreover, the (-)-sulpiride (0.1 micromol/l)-induced increase in evoked dopamine release was also attenuated by superfusion with 0.3 micromol/l beta-phenylethylamine. These data indicate that submicromolar levels of beta-phenylethylamine could modify the dopamine autoreceptor mediated changes in evoked dopamine release from rat striatal slices.     

A case of polyorchidism with embryonal carcinoma

OBJECTIVE: To compare the intraurethral application of liposomal prostaglandin-E1 (PGE1) with intracavernosal injection of PGE1 in patients with organic or psychogenic erectile dysfunction (ED). PATIENTS AND METHODS: Penile tumescence and rigidity were classified by palpation in 25 patients (10 with psychogenic and 15 with organic ED: median age 45 years, range 23-67). All patients were undergoing primary treatment for ED, the median (range) duration of which was 2 3 (2-44) months. After administering PGE1 by each route (1 mg intraurethral and 0.02 or 0.01 mg intracavernosal), the degree of erection was assessed and duplex ultrasonography of the deep penile artery was performed. RESULTS: After the intraurethral application of liposomal PGE1, there was mild penile tumescence in 12 patients with organic ED, the others having no response. In contrast, intracavernosal injection produced sufficient rigidity in 13 patients with organic ED, while two only had a slight increase in tumescence. In patients with psychogenic ED, intraurethral application gave adequate rigidity in six, with four having little or no tumescence, and intracavernosal injection induced sufficient rigidity for intercourse in all. Duplex ultrasonography of the deep penile artery of the penis showed that intraurethral application induced lower flow rates than intracavernosal injection. No patient reported pain after intraurethral application but two of 25 reported severe pain after intracavernosal injection. CONCLUSIONS: The intraurethral application of liposomal PGE1 did not produce sufficient rigidity and was not effective in patients with organic ED. However, it did produce sufficient rigidity in six of 10 patients with psychogenic ED and may thus provide a therapeutic alternative in selected patients.     

New type of Nb3Sn fiber-reinforced superconductors for high-field pulsed magnet and effect of thermal stress

A new type of superconductor with high elastic modulus fibers is being developed for the application of high-field pulsed superconducting magnets called Fiber-Reinforced Superconductors (FRS). FRSs have great potential for the construction of a 15-T class pulses magnet with its size kept equal to ITER because stainless steels of cable-in-conduit-conductors could be reduced considerably. This paper presents a technique of preparing FRS and measuring its superconducting characteristics including strain-Ic relation. FRS has a critical current density of 600 (A/mm²/initial niobium) at 15 T, which is almost equal to one of the commercial bronze-processed wires. The intrinsic strain vs. I_c characteristics are similar to that of bronze-processed wire. Thermal strain on FRS also is discussed because materials with high elastic modulus tend to have low thermal contraction which leads to degradation of the superconducting characteristics of the Nb₃Sn layer. Possibilities of overcoming the degradation while maintaining very high elastic modulus of tungsten fiber for reinforcement are shown.     

Preparation of superabsorbent hydrogels from poly(aspartic acid) by chemical crosslinking

Modified poly(aspartic acid)s containing pendant allyl groups were synthesized by the reaction of poly(succinimide) with an allyl amine in dimethylformamide. The contents of the allyl groups in the poly(aspartic acid) ranged from 2 to 17.4% confirmed by ¹H NMR. Hydrogels were prepared using modified poly(aspartic acid) by chemical crosslinking using redox radical initiators including ammonium persulfate and potassium peroxodisulfate. The morphologies of the poly(aspartic acid)-based hydrogels were investigated by scanning electron microscopy (SEM). The water-absorbent experiments were carried out, and revealed that lightly cross-linked hydrogels resulted in effective water-absorbent properties. These results suggested that allyl group-modified poly(aspartic acid)s are useful in providing biodegradable hydrogels.     

Integration of Computer Assisted Learning in Teaching and Learning in Secondary Schools in Kenya

The purpose of this study was to establish factors that lead to poor integration of Information and communication technology （ICT） for teaching and learning in schools in Kenya, despite comprehensive policy, institutional, infrastructural frameworks and capacity building by the Ministry of Education. The subject of this study was administered by use of questionnaires in three categories of public schools： national school, provincial schools and district schools. The respondents were students from each level that is from one, two, three and four and teachers based on the most offered subjects in the secondary schools. The computer assisted learning facilities were classified into computers, internet and content in optical media. In national school Internet based research, optical media content provided by Kenya Institute of Curriculum Development and Cyber School program for science subjects was used in learning. In provincial school, it lacks adequate computers, reliable Internet and content in optical media. In district school, it lacks adequate computer, no internet connection and content in optical media. A learner management system which can be accessed by all learners by use of any internet access devices like mobile phone access will be an ideal tool with over 4,000,000 mobile phone subscribers currently in Kenya.     

Proton conductive inorganic-organic hybrid membranes functionalized with phosphonic acid for polymer electrolyte fuel cell

Proton conductive sol-gel derived hybrid membranes were synthesized from aromatic derivatives of methoxysilanes and ethyl 2-[3-(dihydroxyphosphoryl)-2-oxapropyl]acrylate (EPA). Two aromatic derivatives of methoxysilanes with different number of methoxy groups were used as the starting materials. Hybrid membranes from difunctional (methyldimethoxysilylmethyl)styrene (MDMSMS(D))/EPA revealed a higher chemical stability and mechanical properties than those from monofunctional (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA. The membrane-electrode assembly (MEA) using the hybrid membranes as electrolytes worked as a fuel cell at 100 °C under saturated humidity. The DMMSMS(M)/EPA membrane-based MEA showed a larger current density than that from MDMSMS(D)/EPA. On the other hand, the MDMSMS(D)/EPA membrane-based MEA exhibited higher open circuit voltages than the DMMSMS(M)/EPA-based MEA, and was stable during fuel cell operation at 80 °C at least for 48 h.     

Swelling behavior of crosslinked hydroxypropylcellulose films retaining cholesteric liquid crystalline order,II. Effects of temperature,solvent, and pH

Crosslinked hydroxypropylcellulose (HPC) films were cast from the cholesteric liquid crystalline HPC solution in methanol. The films retained the cholesteric liquid crystalline order. The dependences of swelling behavior of our films in water and propanol on temperature and on pH of the solvent were determined. The response of our films to the changes in water, temperature and in pH was discussed. In water, the equilibrium swelling ratio (B_e) decreased with temperature whereas B_e increased with temperature in propanol. For a given composition of water and propanol, B_e was independent of temperature. B_e in the acidic solvents was higher than in the alkaline solvents. The response data to the stepwise change in temperature revealed that the deswelling behavior was more rapid than the swelling behavior in water, and the swelling-deswelling behavior was reversible. The response to the stepwise change in pH was almost the same as that of the change in temperature, but the surface of the film was attacked by the acid and became fluffy with increasing soaking time.     

Basic experiments on robot-base vibration control of the hot-line work robot system using genetic algorithm

Past studies on hot-line robot systems have focused on the execution of various hot-line works such as the cutout/connection of electric wires and replacement of insulators. Robot-base vibration control methods, however, have seldom been discussed [1–5]. The high-speed operation of the hot-line work robot system, Phase II, in tasks is being worked on with the goal of practical utilization in the near future. Speed increases in boom and manipulator movements are a key part of this. The Phase II system's boom has a natural frequency of 1.0 Hz in commonly used angles. If the boom or the manipulator is rapidly accelerated, the robot base vibrates violently, hampering task execution. This paper proposes a vibration control method, in which control gain and position command acceleration/deceleration time are optimized for the movement of the robot base. In conjunction with the vibration control, we also focus on the optimization for positioning accuracy and preventing overshoot of the manipulator. These three issues are simultaneously solved using the genetic algorithm. The proposed method has been determined for use in a preliminary experiment for the Phase II system development. A simplified test-bed manipulator of the two-axis horizontal scalar type was employed for simulation and experimentation in order to reduce modeling error. The initial effects brought about by the proposed method are verified. © 1998 Scripta Technica, Electr Eng Jpn, 123(2): 40–52, 1998     

Genome Maintenance Mechanisms at the Chromatin Level

Genome integrity is constantly threatened by internal and external stressors, in both animals and plants. As plants are sessile, a variety of environment stressors can damage their DNA. In the nucleus, DNA twines around histone proteins to form the higher-order structure “chromatin”. Unraveling how chromatin transforms on sensing genotoxic stress is, thus, key to understanding plant strategies to cope with fluctuating environments. In recent years, accumulating evidence in plant research has suggested that chromatin plays a crucial role in protecting DNA from genotoxic stress in three ways: (1) changes in chromatin modifications around damaged sites enhance DNA repair by providing a scaffold and/or easy access to DNA repair machinery; (2) DNA damage triggers genome-wide alterations in chromatin modifications, globally modulating gene expression required for DNA damage response, such as stem cell death, cell-cycle arrest, and an early onset of endoreplication; and (3) condensed chromatin functions as a physical barrier against genotoxic stressors to protect DNA. In this review, we highlight the chromatin-level control of genome stability and compare the regulatory systems in plants and animals to find out unique mechanisms maintaining genome integrity under genotoxic stress.