Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (10^{9.3 ± 0.2} colony-forming units mL⁻¹) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 10^8.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 10^6.8 TBT molecules is adsorbed by a single cell.     

A 63-mW H.264/MPEG-4 audio/visual codec LSI with module-wise dynamic Voltage/frequency scaling

A single-chip H.264 and MPEG-4 audio-visual LSI for mobile applications including terrestrial digital broadcasting system (ISDB-T / DVB-H) with a module-wise, dynamic voltage/frequency scaling architecture is presented for the first time. This LSI can keep operating even during the voltage/frequency transition, so there is no performance overhead. It is realized through a dynamic deskewing system and an on-chip voltage regulator with slew rate control. By the combination with traditional low power techniques such as embedded DRAM and clock gating, it consumes only 63 mW in decoding QVGA H.264 video at 15 frames/sec and MPEG-4 AAC LC audio simultaneously.     

Entirely VPE-grown 1-5?m DFB lasers with low threshold currents

Entirely hydride VPE-grown 1.5?m DFB lasers have been obtained by means of high controllability in film thickness and alloy composition for the GalnAsP/InP system. A low threshold current of 13 mA was achieved by improving the growth method for the layer burying the grating. High uniformity in threshold current and lasing wavelength (Ith = 27.3 ± 9.7 mA, ? = 15571 ± 12?) was obtained.     

Submilliampere lasing of Zn-diffused mesa buried-hetero AlxGa1-xAs/GaAs multi-quantum-well lasers at 77 K

Extremely low-threshold semiconductor lasers were fabricated by forming Zn-diffused mesa buried-hetero (DMB) structures from low-pressure MOCVD-grown AlxGa1-xAs/GaAs multi-quantum-well, separate-confinement heterostructure wafers. CW threshold currents as low as 880 ?A at 77 K and 2.4 mA at room temperature were obtained for a 100 ?m-long device.     

Balanced polarisation diversity receiver with built-in local laser diode

A new heterodyne receiver is demonstrated. The local laser diode (LD) was built-in and no fibre was used between the parts. The number of optical parts and assembly processes was reduced, and a better performance was achieved because there was no polarisation fluctuation of the local light. The effect of a mismatch in the beam profile is discussed.<>     

Differences in thermal salivation between the FOK rat (a model of genotypic heat adaptation) and three other rat strains

Rats secrete saliva in response to heat. In the present study, details of thermal salivation were investigated using the FOK rat in comparison with Sprague-Dawley (SD), Donryu, and ACI rats. The FOK rat is a strain inbred for genotypic heat adaptation and endures heat for long periods. Conscious rats of all four strains were exposed to 42.5 degrees C. The order of heat endurance times at this temperature was FOK > SD > Donryu = ACI. FOK rats spread their saliva over their entire ventral surface, their faces, and their outside legs. This saliva area was wider than those made by the other three strains. SD rats spread in an area wider than those of the Donryu and ACI rats. Saliva spreading in the FOK rats continued for 4.0-4.5 h, far longer than in the other strains. Under ketamine anesthesia and exposure to 40 degrees C, the FOK rats secreted saliva at 1390+/-235 microL/100 g of body weight during a 60-min observation period. This was the highest rate among the four rat strains (p < 0.0001). The body temperature increase rate in anesthetized FOK and SD rats was lower than in the other two strains, suggesting a minor contribution of unknown factors. Ligation of the submandibular gland ducts abolished the thermal salivation of the FOK rats, whereas ligation of the parotid duct had no effect. The submandibular, sublingual, and lachrymal glands in the FOK rats were 1.3-1.5, 1.25-1.4, and 1.3-1.5 times heavier, respectively, than those in the other three strains, whereas the parotid gland of the FOK rats was not enlarged. These findings indicate that the rats' saliva spreading and ET values are significantly correlated. A potentiated and long-lasting salivation from the submandibular gland was acquired during development of genotypic heat adaptation. This salivation is actuated in response to heat. The pronounced thermal salivation is probably attributable to adaptive changes in the superior salivatory nucleus-chorda tympani-submandibular gland pathway.     

Expression of copper trafficking genes in the mouse brain

Copper homeostasis in the brain must be strictly maintained, since copper is an essential trace element and is potentially toxic. To understand the mechanism of copper homeostasis in the brain, we cloned several mouse homologues of copper trafficking genes and performed in situ hybridization histochemistry. mCTR1, mATX1, and mATP7a were highly expressed in the choroid plexus, indicating that the choroid plexus uses the trafficking pathway from uptake to efflux to transport copper to the cerebrospinal fluids. We suggest that these genes may regulate copper concentration in the brain through the choroid plexus.     

Effects of well number, cavity length, and facet reflectivity onthe reduction of threshold current of GaAs/AlGaAs multiquantum welllasers

The optimum design for reducing the threshold current of GaAs/AlGaAs multiquantum well lasers is determined experimentally. The lowest threshold current density is realized by using single and multiquantum wells at long and short cavity lengths, respectively. The threshold current has a minimum at the optimum cavity length: the minimum threshold current is smaller for a larger number of quantum wells, and the optimum cavity length is inversely proportional to the number of wells. Experiments are compared to the theory developed by P.W.A. McIlroy, et al. (ibid., vol.21, no.12, p.1958-63, 1985) and limiting performances of quantum well lasers with various numbers of wells are presented. The reduction of the threshold current by high reflectivity coatings is also demonstrated, and a threshold current as low as 1.86 mA at 15°C is reported     

An experimental 2-bit/cell storage DRAM for macrocell ormemory-on-logic application

A multiple-level 2-bit/cell storage technique for DRAMs (dynamic random-access memories) has been developed. The total RAM area is reduced and the cell array is cut in half. Since the memory cell area is especially defect-sensitive, this technique is highly effective for process yield improvement. Reasonable access time has been realized with this technique: 170 ns is still fast enough for many ASIC (application-specific integrated circuit) memory applications. This technique meets the requirement of high density and moderate speed. It was found that the 2-bit/cell storage technique is suitable for macrocell or memory-on-logic type application