Change in bacterial community during biodegradation of aniline

A modification of the standard electrodiagnostic test was developed in an effort to provide a more sensitive electrodiagnostic evaluation in radial tunnel syndrome. Radial motor nerve latency recordings were obtained in 3 different forearm positions: neutral, passive supination, and passive pronation. The maximal difference in these recordings, the differential latency, in 25 patients with radial tunnel syndrome of greater than 6 months duration (test group) was compared with those in 25 asymptomatic volunteers (control group). Differential latency recordings were obtained in all patients in the test group before and after surgery. Radial nerves that were compressed demonstrated a significantly greater differential latency (0.44+/-0.12 ms) versus controls (0.12+/-0.008 ms). Following radial nerve decompression, differential motor latencies in the test group decreased below control values, demonstrating a resolution of the provoked electrical response with a postoperative differential latency of 0.07+/-0.05 ms. Our results demonstrate the differential motor latency of the radial nerve to be a sensitive electrodiagnostic tool in patients with radial tunnel syndrome. A differential latency of > or =0.30 ms was considered indicative of radial tunnel syndrome.     

High-temperature oxidation of pure titanium in CO2 and Ar-10%CO2 atmospheres

The oxidation behavior of pure titanium has been investigated in the temperature range of 1000 K to 1300 K in CO₂ or Ar-10%CO₂. Optical microscopy, electron probe microanalyses, and X-ray measurements on the oxide scales formed during oxidation indicate that their structures are nearly independent of temperature and the corrosion atmosphere. The scales consisted of two layers, an external one and an internal one, having a rutile (TiO₂) structure. The parabolic rate law was confirmed for growth of the external scale and the permeation depth of oxygen in titanium with apparent activation energies of 266 and 226 kJ/mol, respectively. The rate-determining diffusion species in the oxidation processes are discussed.     

Autonomic load balancing of flow monitors

In monitoring flows at routers for flow analysis or deep packet inspection, the monitor calculates hash values from the flow ID of each packet arriving at the input port of the router. Therefore, the monitors must update the flow table at the transmission line rate, so high-speed and high-cost memory, such as SRAM, is used for the flow table. This requires the monitors to limit the monitoring target to just some of the flows. However, if the monitors randomly select the monitoring targets, multiple routers on the route will sometimes monitor the same flow, or no monitors will monitor a flow. To maximize the number of monitored flows in the entire network, the monitors must select the monitoring targets while maintaining a balanced load among them. We propose an autonomous load-balancing method where monitors exchange information on monitor load only with adjacent monitors. Numerical evaluations using the actual traffic matrix of Internet2 show that the proposed method improves the total monitored flow count by about 50% compared with that of independent sampling. Moreover, we evaluate the load-balancing effect on 36 backbone networks of commercial ISPs.     

Analysis of PD-generated SF/sub 6/ decomposition gases adsorbed on carbon nanotubes

Chemical byproducts analysis has been recognized as a powerful diagnosis method for SF₆ gas-insulated switchgear (GIS). The authors have previously demonstrated that a carbon nanotube (CNT) gas sensor could detect partial discharge (PD) generated in SF₆ gas. However, PD-generated decomposition gas species, which were responsible for the CNT gas sensor response, have not been identified yet. In this paper, two kinds of experiments were conducted in order to identify the responsible decomposition gas species. At first, the decomposition gas molecules adsorbed on CNTs were analyzed by Fourier transformation infrared (FTIR) spectroscopy. FTIR absorbance was observed around 735 cm^-1 after CNTs were exposed to PD generated in SF₆. In the second experiment, the CNT gas sensor responses to typical SF₆ decomposition products (HF and SF₄) were examined. The CNT gas sensor responded to these gases in the same way as to PD generated in SF₆. SF₄ response was larger than HF response. Based on these results, SF ₄ and SOF₂ emerged as candidates for the responsible decomposition gases. Electrochemical interactions between adsorbed gas molecules and CNT were discussed based on theoretical predictions of molecular orbital calculations. The calculation results suggested that both of SOF₂ and SF₄ could increase the CNT gas sensor conductance     

Effect of gravity on InGaSb crystal growth

The effect of gravity on dissolution of GaSb in InSb melt and growth of InGaSb was experimentally investigated. Experiments were carried out in a GaSb(seed)/InSb/GaSb(feed) sandwich system under an imposed temperature gradient. In the experiments, the GaSb feed crystal dissolved into the InSb melt to supply the required GaSb component for the growth of In_0.1Ga_0.9Sb crystal. Two parameters were considered: (1) the inclination angle (θ) of the sample for gravity as 0° and 53°, and (2) the sample diameter (D) as 9 mm and 5mm. When θ was 0°, the interface was almost flat, indicating that convection was axisymmetric and stable. Whereas the interface was distorted towards gravitational direction when θ was 53°, indicating that solutal convection was dominant. The decrease of growth temperature and sample diameter reduced the distortion of interface and the dissolution amount of GaSb feed. The homogeneous crystals were grown at the initial growth stage by supplying the GaSb component during growth.     

Selective enumeration of viable Enterobacteriaceae and Pseudomonas spp. in milk within 7 h by multicolor fluorescence in situ hybridization following microcolony formation

Rapid and simultaneous enumeration of viable Enterobacteriaceae and viable Pseudomonas spp. in milk was achieved by using multicolor fluorescence in situ hybridization (FISH) with oligonucleotide probes based on 16S ribosomal RNA (rRNA) sequences in combination with a microcolony growth method (multicolor microcolony-FISH; MMC-FISH). The procedure of MMC-FISH method is rather simple; that is milk clearing, filtration of cells, incubation, hybridization and enumeration. Enumeration of targeted bacteria in logarithmic growth phase, stationary phase, or in a starved state in milk by MMC-FISH required 5-7 h, while it took 1-3 days to test for Escherichia coli and Pseudomonas putida by the conventional culture method. The numbers of E. coli and P. putida in each phase or in a starved state in milk determined by MMC-FISH were almost the same or greater than the number of colony forming units determined by the plate counting method. The MMC-FISH allows rapid examination of contamination in milk by viable Enterobacteriaceae and Pseudomonas spp. with growth potential.     

Mean–variance relationship of the number of flows in traffic aggregation and its application to traffic management

We consider the mean–variance relationship of the number of flows in traffic aggregation, where flows are divided into several groups randomly, based on a predefined flow aggregation index, such as source IP address. We first derive a quadratic relationship between the mean and the variance of the number of flows belonging to a randomly chosen traffic aggregation group. Note here that the result is applicable to sampled flows obtained through packet sampling. We then show that our analytically derived mean–variance relationship fits well those in actual packet trace data sets. Next, we present two applications of the mean–variance relationship to traffic management. One is an application to detecting network anomalies through monitoring a time series of traffic. Using the mean–variance relationship, we determine the traffic aggregation level in traffic monitoring so that it meets two predefined requirements on false positive and false negative ratios simultaneously. The other is an application to load balancing among network equipments that require per-flow management. We utilize the mean–variance relationship for estimating the processing capability required in each network equipment.     

An Examination of Qubit Neural Network in Controlling an Inverted Pendulum

The Qubit neuron model is a new non-standard computing scheme that has been found by simulations to have efficient processing abilities. In this paper we investigate the usefulness of the model for a non linear kinetic control application of an inverted pendulum on a cart. Simulations show that a neural network based on Qubit neurons would swing up and stabilize the pendulum, yet it also requires a shorter range over which the cart moves as compared to a conventional neural network model.     

Debye Temperature and Electrical Conduction of Fe2O3-CaO-SiO2 Glasses

The electrical conductivity of iron-containing silica glasses was measured from 80 to 350 K. The conductivity data were analyzed based on the hopping conduction theory. The hopping binding energy (W_p) and disorder energy W_D) were calculated from the activation energy at high and low temperatures. The disorder energy obtained was much lower than reported for FeO-P₂O₅ glasses, but similar to that for vandium-containing glasses.     

Alteration of substrate specificity of cholesterol oxidase from Streptomyces sp. by site-directed mutagenesis

Despite the structural similarities between cholesterol oxidasefrom Streptomyces and that from Brevibacterium, both enzymesexhibit different characteristics, such as catalytic activity,optimum pH and temperature. In attempts to define the molecularbasis of differences in catalytic activity or stability, substitutionsat six amino acid residues were introduced into cholesteroloxidase using site-directed mutagenesis of its gene. The aminoacid substitutions chosen were based on structural comparisonsof cholesterol oxidases from Streptomyces and Brevibacterium.Seven mutant enzymes were constructed with the following aminoacid substitutions: L117P, L119A, L119F, V145Q, Q286R, P357Nand S379T. All the mutant enzymes exhibited activity with theexception of that with the L117P mutation. The resulting V145Qmutant enzyme has low activities for all substrates examinedand the S379T mutant enzyme showed markedly altered substratespecificity compared with the wild-type enzyme. To evaluatethe role of V145 and S379 residues in the reaction, mutantswith two additional substitutions in V145 and four in S379 wereconstructed. The mutant enzymes created by the replacement ofV145 by Asp and Glu had much lower catalytic efficiency forcholesterol and pregnenolone as substrates than the wild-typeenzyme. From previous studies and this study, the V145 residueseems to be important for the stability and substrate bindingof the cholesterol oxidase. In contrast, the catalytic efficiencies(k_cat/K_m) of the S379T mutant enzyme for cholesterol and pregnenolonewere 1.8- and 6.0-fold higher, respectively, than those of thewild-type enzyme. The enhanced catalytic efficiency of the S379Tmutant enzyme for pregnenolone was due to a slightly high k_catvalue and a low K_m value. These findings will provide severalideas for the design of more powerful enzymes that can be appliedto clinical determination of serum cholesterol levels and assterol probes.