Determination of pyridonecarboxylic acids in plasma by reverse-phase high-performance liquid chromatography

A simple qualitative and quantitative determination for pyridonecarboxylic acids including nalidixic acid (NA), oxolinic acid (OA) and pipemidic acid (PPA) in chicken plasma was carried out by microbiological, spectrophotometric, thin-layer chromatographic (TLC) and reverse-phase high-performance liquid chromatographic (HPLC) methods. As a test organism for bacteriological bioassay, Bacillus subtilis ATCC-6633 was the most sensitive of seven organisms investigated. Using the cup and the disc methods, a standard curve was obtained by determining the relationship between various drug concentrations and the diameter of the inhibition zone. The three drugs had two strong UV absorbance wavelengths (257 and 330 nm) on spectrophotometry. TLC analysis using a silica gel 60 F254 plate was investigated, and a solution of methanol:chloroform:acetic acid (3:1:1, v/v/v) was found to be the most suitable solvent for separation. The minimum concentration of drug detectable by this method was 0.5 microgram/ml for NA, 0.075 microgram/ml for OA and 0.39 microgram/ml for PPA. For HPLC analysis, a solution of acetonitrile:0.2 M phosphoric acid (1:1, v/v) was superior, and simultaneous determination of all three drugs was possible under the HPLC conditions used. The lowest measurable amount of drug in chicken plasma was 0.01 microgram/g. Recovery from extracts spiked with each drug at a known concentration was close to 100% for NA and OA, but only about 50% for PPA.     

Cryogenic capacitive transimpedance amplifier for astronomical infrared detectors

We have developed a new capacitive transimpedance amplifier (CTIA) that can be operated at 2 K, and have good performance as readout circuits of astronomical far-infrared array detectors. The circuit design of the present CTIA consists of silicon p-MOSFETs and other passive elements. The process is a standard Bi-CMOS process with 0.5 /spl mu/m design rule. The open-loop gain of the CTIA is more than 300, resulting in good integration performance. The output voltage swing of the CTIA was 270 mV. The power consumption for each CTIA is less than 10 /spl mu/W. The noise at the output showed a 1/f noise spectrum of 4 /spl mu/V//spl radic/Hz at 1 Hz. The performance of this CTIA nearly fulfills the requirements for the far-infrared array detectors onboard ASTRO-F, Japanese infrared astronomical satellite to be launched in 2005.     

Activation of G1 progression, JNK mitogen-activated protein kinase, and actin filament assembly by the exchange factor FGD1

Cdc42 has been shown to control bifurcating pathways leading to filopodia formation/G1 cell cycle progression and to JNK mitogen-activated protein kinase activation. To dissect these pathways further, the cellular effects induced by a Cdc42 guanine nucleotide exchange factor, FGD1, have been examined. All exchange factors acting on the Rho GTPase family have juxtaposed Dbl homology (DH) and pleckstrin homology (PH) domains. We report here that FGD1 triggers G1 cell cycle progression and filopodia formation in Swiss 3T3 fibroblasts as well as JNK mitogen-activated protein kinase activation in COS cell transfection assays. FGD1-induced filopodia formation is Cdc42-dependent, and both the DH and PH domains are essential. Although expression of the FGD1 DH domain alone does not activate Cdc42 and induce filopodia, it does trigger both the JNK cascade in COS cells and G1 progression in quiescent Swiss 3T3 cells. We conclude that FGD1 can trigger G1 progression independently of actin polymerization or integrin adhesion complex assembly. Furthermore, since FGD1 activates JNK and G1 progression in a Cdc42-independent manner, it must have additional, as yet unidentified, targets.     

AKP energy levels by a simple shooting scheme for a periodic orbit

We revisit the periodic orbit theory for the anisotropic Kepler problem, which is an important playground for quantum chaos. In order to explore the periodic orbit, Gutzwiller devised an iteration scheme which computes the Fourier coefficients of the orbit iteratively. Here we note, in a nutshell, that all one needs is the primary periodic orbit. We propose an alternative scheme taking into account the symmetry of the target trajectory and the scaling property of the AKP equation of motion. We show that a simple shooting scheme gives the final periodic orbit almost immediately.     

Responsibility of electric resistance of polyethyleneimine-grafted carbon black against alcohol vapor and humidity

Crystalline polyethyleneimine (PEI(C)) was successfully grafted onto carbon black surface by direct condensation of imino groups of PEI with carboxyl groups on the surface using N,N′-dicyclohexylcarbodiimide as a condensing agent. The electric resistance of a composite prepared from PEI(C) and PEI(C)-grafted carbon black drastically increased to 10³ – 10⁴ times of initial resistance in methanol, ethanol, and water vapor. But the change of electric resistance of the composite hardly observed in hexane and toluene vapor. These results suggest the possibility of detection of a slight change of crystalline structure of PEI by the absorption of solvent as a large increase of electric resistance of the composite. Received: 11 April 1997/Revised: 16 June 1997/Accepted: 23 June 1997     

High-performance FCBGA based on multi-layer thin-substrate packaging technology

We developed a new concept flip-chip ball grid array (FCBGA) based on multi-layer thin-substrate (MLTS) packaging technology in order to meet the strong demand for high-density, high-performance, and low-cost LSI packages. The most important feature of MLTS packaging is that, only a high-density and high-performance MLTS remains by removing the metal plate after mounting an LSI chip. The MLTS packaging offers the advantages of (1) good registration accuracy, which makes higher-density and finer-pitch pattering possible; (2) an ideal multi-layer structure that is highly suitable for high-speed and high-frequency applications; (3) excellent flip-chip mounting reliability, which makes higher-pin-count and finer-pitch area array flip-chip interconnection possible; (4) excellent reliability, supported by use of high T_g (glass transition temperature) resin; and (5) a cost-effective design achieved as a result of fewer layers fabricated with fine-pitch patterning.We successfully produced a high-performance FCBGA prototype based on our MLTS packaging technology. The prototype comprises an LSI chip connected to approximately 2500 bonding pads arranged in 240 μm pitch area array, and 1296 I/O pads for BGA. The prototype FCBGA’s excellent long-term reliability was demonstrated through a series of tests conducted on it.     

Preparation of a fine powder composed of oxide–metal composite by an arc-plasma method

Fine oxide–metal composite powders have been prepared under an H₂–Ar gas environment using an arc-plasma irradiation technique. Initial Cu particles with grain sizes between 10 and 30 μm were mixed with TiO₂ powder of submicron size at different weight ratios to form targets by sintering. Mixtures with varying Cu/TiO₂ weight ratios were prepared, but mostly a mixture with the weight ratio at 95:5 was used. The targets were exposed to arc-plasma irradiation to form a fine composite powder. Particles prepared are Cu-fine core particles each coated with a thin film of TiO₂. The thickness of the oxide film ranges from a few nanometers to some tens of nanometers, and is independent of the ambient gas composition and irradiation. The size distribution of prepared composite particles is broad, and most of them range from 20 to 100 nm. H₂ gas in the chamber plays a significant role in forming the composite powder.     

Microcomputer-aided insulin dose determination in intensifiedconventional insulin therapy

A microcomputer program is presented that gives information when insulin-dependent diabetes mellitus (IDDM) patients need to make decisions regarding the insulin regimen in intensified conventional insulin therapy in conjunction with self-monitoring of blood glucose. This information consists of the optimum insulin dose and timing of its administration that these IDDM patients need. Estimates were made by a statistical approach based on the impulse response of blood glucose to a bolus injection of insulin (insulin sensitivity) calculated from blood glucose profiles, which consisted of nine daily blood glucose level measurements. This information is objective because it is mathematically substantiated, and useful because it can be obtained from insulin sensitivity     

Field emission SEM, conventional TEM and HVTEM study of submandibular gland in prenatal and postnatal aging mouse

The development of acinar and ductal cells of the mouse submandibular gland was studied using field emission SEM, conventional TEM and HVTEM methods. The specimens, at 15 and 18 days of gestation and 1, 3, 7, 14, 21, 30, 90 and 180 postnatal days were fixed in 2.5% glutaraldehyde solution in 0.1 M sodium phosphate buffer (pH 7.3). At 15 and 18 days of gestation, the structure of mouse submandibular gland contains acinar and ductal cells in proliferation. The cytoplasmic organelles such as mitochondria, granular endoplasmic reticulum and Golgi apparatuses are scattered in the cytoplasm. At 18 prenatal days only several acinar cells present immature secretory granules in the apical portion. In this stage the acinar and ductal cells are enveloped by bundles of fine collagen fibrils disposed in several directions. There are also numerous capillaries located closely to the acinar cell membranes. In the aging stages of 1, 3, 7, 14, 21, and 30 postnatal days, the histo-differentiation of acinar, intercalated and ductal cell components are observed. At newborn day one the cytoplasmic organelles start to place themselves around the nucleus. Several immature secretory granules are observed at day one, however, they increase in the aging days. At postnatal day 30, the cytoplasms of acinar and ductal cells are filled with a large number of secretory granules of different sizes. The stacks of granular endoplasmic reticulum and Golgi apparatus and some vesicles and free ribosomes are noted. The intercellular membranes are attached by desmosomes and cytoplasmic interdigitations. The luminal surface shows several small projections of microvilli. An electron-dense line of basement membranes followed by fine collagen fibrils are recognized. Delicate capillaries are found in the outer surface of acinar cells. At postnatal day 90 and 180 the acinar, intercalated and striated ductal cells reveal numerous secretory granules in the apical portion. The acinar cells showed basal nuclei and the parallel arrangement of granular endoplasmic reticulum. The mitochondria are located at the base of ductal cells showing a typical pattern of cristae. In these stages the intercellular digitations of cytoplasmic protrusions and desmosomes are also noted. The cytoplasm of myoepithelial cells are seen along the cell membranes. The spongy-like structures constituting the basement membrane are followed by bundles of fine collagen fibers.     

A 2.5-ns clock access, 250-MHz, 256-Mb SDRAM with synchronousmirror delay

A 256-Mb SDRAM (245.7 mm²) has been developed using (1) a high cell occupation ratio (60.2%) array design for chip size reduction and a high yield, (2) a prefetched pipeline scheme (PPS) using a first-in first-out (FIFO) buffer with parallel serial converter for 250-MHz clock frequency operation, and (3) a synchronous mirror delay (SMD) circuit for 2.5-ns clock access and low standby current