Comparison of Risk Calculation Methods for a Culvert

A comparative study of eight different risk calculation methods has been performed on the occurrence probability of inadequate capacity of a culvert to pass floods. The five basic risk calculation methods used in this study are the mean-value first-order second-moment method, advanced first-order second-moment method, point estimate method, Latin hypercube sampling method, and Monte Carlo simulation. Two options each for the point estimation and Monte Carlo methods are also investigated. Building upon the first four basic calculation methods, three additional methods are suggested. They are the first-order second-moment mixed mode method, generalized mixed mode method, and significant component method. Within each of the first four basic methods risks are calculated, whenever possible, using two definitions of failure parameter, i.e., (1) the performance function Z directly as a function of all the contributing variables; and (2) separate calculations of loading and resistance (capacity). Logic trees are presented to illustrate possible causes of culvert failure, the ways to account for component factors such as those from hydraulics and hydrology and to combine the component risks for total risk. Risk of inadequate flow capacity for a five-foot diameter culvert is evaluated as an example. Three sets of uncertainty data for the random variables are used; the first set data is adopted from a study in the literature, in which uncertainties from loading dominate. The second set of data is hypothetical with resistance uncertainties as the major contribution to failure; whereas in the third set, loading and resistance have about equal contributions of uncertainties. The relative errors of computed risks with respect to Monte Carlo simulation results are compared. The results show that for conditions similar to those tested, most of the methods are computationally simpler than the Monte Carlo simulation, and can be used for risk calculation. Cautions to some of the methods are remarked.     

Changes in the specificity of antibodies by site-specific mutagenesis followed by random mutagenesis

The specificity for 11-deoxycortisol (11-DOC) of a monoclonalantibody (mAb), designated SCET, was changed to specificityfor cortisol (CS) by site-specific mutagenesis followed by randommutagenesis. The Fab form of SCET was expressed on the surfaceof a phage. During the first step, mutations were introducedat 14 amino acid positions in three complementarity-determiningregions (CDRs) of the V_H domain that seemed likely to form thesteroid-binding pocket. A clone, DcC16, was isolated from theresultant library with multiple mutations and this clone wasshown to have CS-binding activity but also to retain high 11-DOC-bindingactivity. During the second step, mutations were introducedrandomly into the entire V_H-coding region of the DcC16 cloneby an error-prone polymerase chain reaction, and CS-specificmutant antibodies were selected in the presence of 11-DOC asa competitor. Three representative clones were analyzed withthe BIAcore instrument, and each revealed a large increase inthe binding constant for CS and a decrease in that for 11-DOC.Structural models, constructed by computer simulation, indicatedthe probable molecular basis for these changes in specificity.     

Preparation of 200 nm BaTiO3 Particles with their Tetragonality 1.010 Via a Solid-State Reaction Preceded by Agglomeration-Free Mechanical Activation

Well-dispersed barium titanate (BaTiO₃; BT) with an average primary particle size <200 nm and lattice tetragonality 1.010, being very close to that of a BT single crystal, was obtained via a solid-state route with the aid of preliminary dry mechanical processing. The latter treatment not only activates the starting mixture but also decreases the particle sizes of individual ingredients and increases the homogeneity. All these favor to suppress grain growth of the product BT due to increasing nucleation site density, easing the nucleation at the given nucleation site, and decreasing the diffusion paths. These were confirmed by (i) microscopy and particle size analysis to observe downsizing of individual particulates without causing agglomeration; (ii) electron probe microanalysis to reveal increase in the homogeneity in a few micrometer regime; and (iii) X-ray photoelectron spectroscopy to reveal mechanochemical effects across the solid–solid boundary of dissimilar particles.     

Development of a universal ellipsoidal mirror device for fluorescence detected circular dichroism: elimination of polarization artifacts

We have developed an ellipsoidal mirror fluorescence detected circular dichroism (FDCD) device with enhanced detection sensitivity that eliminates the polarization artifact; this is applicable to samples with strongly polarized fluorescence. The device, JASCO FDCD465, has an ellipsoidal mirror structure with a framework consisting of three mirrors (one elliptical and two plane mirrors) that maximally collects light in the FDCD. All assemblies on the device including the ellipsoidal mirror, cylindrical cell, and photomultiplier tube (PMT) are aligned on the chamber-fitting sample mount as an attachment compatible with a standard CD spectropolarimeter. The new FDCD465 device eliminates the polarization artifact caused by anisotropic distribution of the emitted light. It represents a convenient, reliable, and sensitive FDCD attachment to the JASCO J-800 CD spectrometer series that can be used under both isotropic and photoselected conditions.     

Determining the lifetime of CD‐RWs using efficient sampling on a production line

This work derives the intermittent batch size and sample size for product life testing on a production line. The sequential probability ratio test was adopted to determine the sample size, , and the expected number of samples (ENS). An inverse chi‐square approximation was used to determine the relationship between the degree of freedom, , and the estimated range of at various levels of confidence. Consequently, ENS and were used to determine the intermittent batch size, . Finally, rewritable compact disks (CD‐RWs) underwent testing to demonstrate the feasibility and effectiveness of the proposed efficient sampling approach. Copyright © 2003 John Wiley & Sons, Ltd.     

Polymerase chain reaction assay for detection of Escherichia coli O157: H7 and Escherichia coli O157: H-.

The DNA band patterns generated by polymerase chain reaction (PCR) using the du2 primer and template DNAs from various strains of Escherichia coli and non-E. coli bacteria were compared. Among three to five prominent bands produced, the three bands at about 1.8, 2.7, and 5.0 kb were detected in all of the E. coli O157 strains tested. Some nonpathogenic E. coli and all pathogenic E. coli except E. coli O157 showed bands at 1.8 and 5.0 kb. It seems that the band at 2.7 kb is specific to E. coli O157. Sequence analysis of the 2.7-kb PCR product revealed the presence of a DNA sequence specific to E. coli O157:H- and E. coli O157:H7. Since the DNA sequence from base 15 to base 1,008 of the PCR product seems to be specific to E. coli O157, a PCR assay was carried out with various bacterial genomic DNAs and O157-FHC1 and O157-FHC2 primers that amplified the region between base 23 and base 994 of the 2.7-kb PCR product. A single band at 970 bp was clearly detected in all of the strains of E. coli O157:H- and E. coli O157:H7 tested. However, no band was amplified from template DNAs from other bacteria, including both nonpathogenic and pathogenic E. coli except E. coli O157. All raw meats inoculated with E. coli O157:H7 at 3 x 10(0) to 3.5 x 10(2) CFU/25 g were positive both for our PCR assay after cultivation in mEC-N broth at 42 degrees C for 18 h and for the conventional cultural method.     

Multichannel Implantable Stimulator for Control of Paralyzed Muscle

An implantable stimulator has been developed for excitation of paralyzed muscle. The stimulator is radio frequency powered and controlled, and has four output channels; there are three sequentially fired and the fourth is independently controlled. The width of each stimulus pulse and the group stimulus frequency are controlled independently by the absence of the 25 MHz powering carrier. The stimulator has been implemented in a thick film hybrid circuit. The circuitry is encapsulated in a ceramic (Macor?) , which has hermetically sealed feed throughs for electrode lead wires.     

Sample tilting technique for preventing electrostatic discharge during high-current FIB gas-assisted etching with XeF2

FIB-induced electrostatic discharge (ESD) is a major limiting factor for achieving successful and efficient circuit modifications of LSI. We have discovered a novel antistatic technique applicable to high-current (nanoampere-order) FIB gas-assisted etching with XeF₂. The method simply utilizes inclined incidence of FIB by sample tilting. The effect of the sample tilting technique on preventing ESD was investigated using a logic LSI device fabricated by 0.13 μm technology and eight-layer copper metallization. The result demonstrated that inclined incidence of 60° prevents ESD even for high-current (12.5 nA) FIB gas-assisted etching with XeF₂. The mechanism of ESD suppression by the sample tilting technique was proposed by taking account of the presence of processing gas molecules and the tilting-angle dependences of ion range, back-scattering yield, secondary-electron yield and etching rate. In the case of FIB irradiation at inclined incidence with XeF₂ gas flow, more secondary-electrons and sputtered particles are ejected with higher energies than those for the case of normal incidence. This leads the ionization probabilities of neutral gases and the sputtered particles to be increased, and results in producing increased low-energy electrons around the FIB processing area. These low-energy electrons suppress the FIB-induced positive charging.     

The Functional Diversity of Nitric Oxide Synthase Isoforms in Human Nose and Paranasal Sinuses: Contrasting Pathophysiological Aspects in Nasal Allergy and Chronic Rhinosinusitis

The human paranasal sinuses are the major source of intrinsic nitric oxide (NO) production in the human airway. NO plays several roles in the maintenance of physiological homeostasis and the regulation of airway inflammation through the expression of three NO synthase (NOS) isoforms. Measuring NO levels can contribute to the diagnosis and assessment of allergic rhinitis (AR) and chronic rhinosinusitis (CRS). In symptomatic AR patients, pro-inflammatory cytokines upregulate the expression of inducible NOS (iNOS) in the inferior turbinate. Excessive amounts of NO cause oxidative damage to cellular components, leading to the deposition of cytotoxic substances. CRS phenotype and endotype classifications have provided insights into modern treatment strategies. Analyses of the production of sinus NO and its metabolites revealed pathobiological diversity that can be exploited for useful biomarkers. Measuring nasal NO based on different NOS activities is a potent tool for specific interventions targeting molecular pathways underlying CRS endotype-specific inflammation. We provide a comprehensive review of the functional diversity of NOS isoforms in the human sinonasal system in relation to these two major nasal disorders’ pathologies. The regulatory mechanisms of NOS expression associated with the substrate bioavailability indicate the involvement of both type 1 and type 2 immune responses.