bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparison of the songs of the tufted and black-crested titmice.
Authors: Coldren Cade L.
Published: October 2005

The songs of the Eastern tufted titmouse (Parus B. bicolor) and the black-crested titmouse (Parus B. sennetti) were examined as a possible systematic tool. From nine sites, 65 song types were identified, falling into four categories: one-note phrase, two-note long-short phrase, two-note short-long phrase, and three-note phrase songs. Canonical discriminant analysis on morphometric parameters revealed greater variation in song between sites than within sites. Black-crested titmice typically sing at higher dominant frequencies, shorter phrase durations, a higher number of phrases per song, and a smaller repertoire than tufted titmice. Black-crested repertoires were composed mostly of one-note phrase songs and a few two-note phrase songs. Tufted titmice repertoires had approximately equal proportions of one-note and two-note phrase songs with one three-note phrase song at each site. Differences in body size and habitat density may explain the higher dominant frequencies found at black-crested sites. The possible occurrence of dialects and the role of learning may account for all differences in song. However, their impacts on titmice songs must be determined before song can be used as a reliable systematic tool for the tufted titmouse complex.
The acoustics of snapping shrimp in Kaneohe Bay.
Authors: Au Whitlow W. L. , Banks Kiara
Published: October 2005

Snapping shrimp are among the major contributors of biological noise in shallow bays, harbors, and inlets located in temperate and tropical waters. Snapping shrimp sounds can severely limit the use of underwater acoustics by humans and other animals such as dolphins, whales, and pinnepeds. They produce sounds by rapidly closing their frontal chela, or claws, snapping the two ends together to generate a loud click. The acoustics of the species Synalpheus paraneomeris was studied by measuring the sound produced by individual shrimp housed in a small cage located 1 m from an H-52 broadband hydrophone. Ten clicks from 40 specimens were digitized at a 1-MHz sample rate and the data stored on disk. Various acoustic parameters such as source level, spectral content, and center frequency were correlated with claw size and body length. Peak-top-peak source levels varied from 183 to 189 dB re: 1 μPa. A typical spectrum had a low-frequency peak between 2 and 5 kHz and energy extending out to 200 kHz.
Mode control of ultrasonic guided waves in thick cylinders for crack detection.
Authors: Li Zongbao , Berthelot Yves H.
Published: October 2005

Experiments on ultrasonic propagation in thick annular structures show that one can simplify the modal structure of the received signals by carefully controlling the wedge angles of the generation and detection transducers. This is important if one is to detect cracks along the path between source and receiver. In particular, one should excite and detect only those modes whose energy is concentrated where the cracks are expected to form. To do so, the following methodology is used: First, experimental signals are obtained for various source–receiver configurations with a standard pulser/receiver; a wavelet transform is then applied to the signals to localize precisely in time the arrival of a given mode packet at a given frequency and to determine the corresponding group velocity. These modes are then identified by comparing the results with predictions from theoretical dispersion curves. One can then predict the energy distribution within the structure by using the method of normal mode expansion for transients. [Work supported by the ONR, Code 332.]
Modification of two methods for determining acoustic impedance.
Authors: Jones Michael G. , Stiede Patricia E.
Published: October 2005

Results of an investigation to modify two impedance measurement methods (two-microphone method, TMM; and multipoint method, MPM) to improve efficiency and convenience are presented. The TMM is modified by eliminating the need for one of the microphones in situations where only one microphone can be placed into the test environment. The MPM modification uses pseudorandom noise to significantly reduce the time necessary to complete acoustic impedance measurements. These modifications are the results of on-going technology development at NASA Langley Research Center to simplify and increase accuracy of measurements in harsh environments. Evaluations of efficiency and accuracy requirements of each of the normal incidence acoustic impedance measurement techniques in use at NASA Langley Research Center are provided to determine which method should be used for a given problem. The single-tone source implementation of the MPM is found to be the most accurate, but the most time-consuming technique currently in use. A pseudorandom noise source implementation of the MPM requires significantly less time, with minimal loss of accuracy. The single-microphone method (SMM) is shown to be accurate with a single discrete frequency source, but degrades in accuracy with a random noise source.
Comparisons of approximate and exact techniques for convected acoustics.
Authors: Leep Laurine , Dowling David R.
Published: October 2005

In many aero- and environmental-acoustic problems, convection of sound waves is handled by appropriately increasing or decreasing the local speed of sound and then solving the resulting Helmholtz equation. Such solutions are typically obtained via integral transforms or geometrical acoustics. An exact solution technique that properly incorporates the vector character of mean-flow convection has been found [L. Nijs and C. P. A. Wapenaar, J. Acoust. Soc. Am. 87, 1987–1998 (1987)]. Unfortunately, the formal and numerical complexity of these techniques has prevented detailed comparisons of the acoustic field variables with and without the standard approximation. Results and comparisons for approximate and exact treatment of convection will be presented from a series of simple computations made directly from the linearized time- and space-dependent equations of inviscid fluid motion. Specifically, the propagation of initially plane acoustic waves in a simple shear flow has been addressed to determine how: (i) wavefront orientation and location, (ii) acoustic-particle-velocity vector direction, and (iii) acoustic wave strength compare when mean flow convection is handled approximately and exactly. [Work supported by Ford Motor Company.]
Dynamic shear modulus measurement technique for very soft materials.
Authors: Donskoy Dimitri M. , Bang Gyoo-Cheol
Published: October 2005

Existing methods of dynamic viscoelastic properties measurements have some limitation with respect to softness of material, its spatial anisotropy, and frequency range. Specifically, there are very limited capabilities to measure dynamic shear moduli of very soft (real shear modulus value is below 104 Pa) and anisotropic materials such as biological tissue and some polymers. The proposed technique is intended to fill this niche. The method utilizes the resonance approach, in which the specimen with certain orientation is treated as a massless spring attached to a massive rigid plate. The plate is excited with a one-dimensional forced vibration in such a way that the specimen has only shear deformation. The resonance oscillation of the plate is analyzed with an impedance head and a spectral analyzer. Once the resonance frequency and the quality factor of the resonance are obtained, the complex shear modulus of the specimen can be calculated. An experimental setup utilizing the proposed approach was built and the complex shear moduli of soft biological tissue with respect to different orientations of the fibers were measured.
Relation between total power output and input phase of underwater transducer array elements made of piezo-rubber.
Authors: Mikami Daiji , Hasegawa Akio , Kikuchi Toshiaki
Published: October 2005

The mutual interaction of underwater acoustic transducer array elements is one of the most important factors for its transmission performance. The power output from each array element is characterized by mutual radiation impedance between array elements. Recently numerical simulations are often applied to solve this kind of problem. Generally PZT transducer array is used in experiments but mechanical Q of PZT transducer is high and the range of measuring frequency is limited in narrow band. So many sizes of transducer array models are required to evaluate in different frequencies. Composite material piezo-rubber has unique properties. Its flexibility and broadband resonance character by low mechanical Q allow experiments in various frequencies utilizing one array apparatus. Consequently a flexible method of model experiment using piezo-rubber sheet transducer array is introduced. The total power output versus input phase of 3 × 3 piezo-rubber transducer array provides the effects of interaction between array elements in various frequencies and input amplitudes. Also near field 3-D mapping of real power and imaginal power shows radiation performance of this transducer array visually. A clear power reduction was observed in the case of a −180-deg phase shift pattern.
Second harmonic generation in a sound beam incident on a liquid–solid interface near the Rayleigh angle.
Authors: Landsberger B. J. , Hamilton M. F. , Il’inskii Yu. A. , Zabolotskaya E. A.
Published: October 2005

When a beam of sound is incident on an elastic half-space at the Rayleigh angle, the rapid variation of the phase of the reflection coefficient produces the classical effect known as beam displacement. Considered here is the corresponding effect on the second harmonic component generated nonlinearly in the fluid. Experiments were performed in water with a 1-MHz beam radiated from a circular source of radius 1.2 cm. The beam was incident on an aluminum block at several angles near and at the Rayleigh angle. A quasilinear theory was developed in which the primary beam is decomposed into its angular spectrum. Analytic solutions were derived for second harmonic generation by pairs of angular spectrum components in the incident and reflected fields. The analytic solutions are superposed, and the second harmonic field is constructed from the resulting angular spectrum. There are no restrictions on source geometry or angle of incidence. Theory is in excellent agreement with experiment. Calculations reveal that in the reflected field, second harmonic components generated separately in the incident and reflected beams combine constructively in regions associated with specular reflection, and destructively in regions associated with radiation by the Rayleigh wave. [Work supported by ONR and the Schlumberger Foundation.]
Detection of change without regard to its valence.
Authors: Hafter Ervin R. , Bonnel Anne-Marie , Gallun Erick J.
Published: October 2005

When an increment (S+) or a decrement (S−) is added to an ongoing pedestal in a detection task, performance is far better than when all trials have a signal and the task is to identify its valence. This is the opposite of predictions from a standard detection theoretical analysis. It has been suggested that the detection task reflects sensitivity to transients associated with stimulus change while identification task reflects analysis of the sustained level, i.e., the energy. To be complete, this must argue that detection is of absolute change, regardless of its sign. To test this, detectability was measured with bidirectional signals (S+) and (S−) was compared that with only a single signal type, either (S+) or (S−). This was done in paradigms: (1) with the pedestal constant and (2) with gaps in the pedestal on either side of the signal that prevented the use change per se. Results show the hypothesis, showing that monodirectional signals were equally detectable as bidirectional signals when there were no gaps but with gaps, they were better.
Variance and invariants in room acoustics: A random walk through reverberant fields.
Authors: Lubman David
Published: October 2005

The understanding of room reverberation has advanced notably in recent decades owing to the merging of statistical communication theory with room acoustics. New invariants expressed as simple and robust statistical laws govern steady-state variation of reverberant sound pressure over time, frequency, and space. Much of statistical room acoustics (SRA) theory can be developed by applying random walk theory to classical room acoustics. Reverberation time (T60) controls the variance of reverberant pressure with frequency at each room location. The ‘‘reverberation time-bandwidth’’ (BT60) product controls spatial variance. SRA contradicts the conventional wisdom that ‘‘hot spots’’ and ‘‘dead spots’’ indicate poor diffusion, implying instead that spatial variations are inevitable even in a perfectly diffuse field. SRA facilitated new measurement standards for estimating pure tone sound power in reverberation rooms by providing objective guidance for optimization of spatial averaging and estimation of error bounds. SRA points to fundamental uncertainties in low-frequency room behavior and connects room acoustics to the kinetic theory of gases. Using statistical theory to solve deterministic problems of room reverberation may seem paradoxical if not heretical. Yet SRA continues to provide unexpected insights and discoveries impacting room acoustic thinking and practice. This paper recounts developments from a research participant’s perspective.
Surveillance for isocyanate asthma: a model based cost effectiveness analysis
Authors: Wild D M , Redlich C A , Paltiel A D
Published: October 2005

Aims:Because logistical and financial obstacles impede using large prospective cohort studies, surveillance decisions in occupational settings must often be made without evidence of relative benefits and costs. Using the example of isocyanate induced asthma, the most commonly reported immune mediated occupational asthma, the authors developed a model based approach to evaluate the costs and benefits of surveillance from both an employer and a societal perspective.

Methods:The authors used a mathematical simulation model of isocyanate asthma to compare annual surveillance to passive case finding. Outcome measures included symptom free days (SFD), quality adjusted life years (QALY), direct costs, productivity losses, and incremental cost effectiveness ratio (CER), measured from the employer and the societal perspectives. Input data were obtained from a variety of published sources.

Results:For 100 000 exposed workers, surveillance resulted in 683 fewer cases of disability over 10 years. Surveillance conferred benefits at an incremental cost of $24,000/QALY (employer perspective; $13.33/SFD) and was cost saving from the societal perspective. Results were sensitive to assumptions about sensitisation rate, removal rates, and time to diagnosis, but not to assumptions about therapy costs and disability rates.

Conclusions:Baseline results placed the CER for surveillance for isocyanate asthma within the acceptable range. Costs from the societal and employer perspective differed substantially with a more attractive CER from the societal perspective, suggesting opportunities for employer/societal cost sharing. The analysis demonstrates the value of a model based approach to evaluate the cost effectiveness of surveillance programmes for isocyanate asthma, and to inform shared decision making among clinicians, patients, employers, and society. Such a modeling approach may be applicable to surveillance programmes for other work related conditions.
Incidence of allergy and allergy symptoms among workers exposed to laboratory animals
Authors: Elliott L , Heederik D , Marshall S , Peden D , Loomis D
Published: October 2005

Background and Aims:Few studies have described relations between exposure to laboratory animals and the incidence of laboratory animal allergy (LAA). Studies that have found exposure-response relations have been cross sectional in design or have focused on exposure to rats and mice. This study used longitudinal data collected over a 12 year period to describe the relations between indices of exposure to laboratory animals and the development of LAA and LAA symptoms.

Methods:Data were obtained from questionnaires and serological laboratory results from a dynamic cohort of workers exposed to a variety of laboratory animals in a pharmaceutical manufacturing company. Poisson regression was used to model the incidence rate ratios of species specific and general LAA and LAA symptoms at different levels of exposure.

Results:The 12 year incidence rates of LAA symptoms and LAA for all workers were 2.26 (95% CI 1.61 to 2.91) and 1.32 (95% CI 0.76 to 1.87) per 100 person-years, respectively. Higher rate ratios were seen with increasing reported hours of exposure to tasks that required working with animal cages or with many animals at one time. The most common symptoms were related to rhinitis rather than to asthma.

Conclusions:This study suggests that the risk of LAA increases with duration of exposure to animals and work in animal related tasks. Incidence might be reduced by limiting hours per week of exposure to laboratory animals.
Single-fiber isolation and maintenance of satellite cell quiescence
Authors: Wozniak Ashley C , Anderson Judy E
Published: October 2005

The activity of satellite cells during myogenesis, development, or skeletal muscle regeneration is strongly modelled using cultures of single muscle fibers. However, there are variations in reported features of gene or protein expression as examined with single-fiber cultures. Here, we examined the potential differences in activation of satellite cells on normal mouse muscle fibers produced during a standard isolation protocol, with or without agitation during collagenase digestion. Activation was detected in satellite cells on fibers after 24 and 48 h of culture in basal growth medium using immunodetection of the incorporation of bromodeoxyuridine (BrdU) into DNA and quantification of the number of BrdU-positive cells per fiber. After 24 and 48 h in culture under nonactivating conditions, the number of activated (BrdU+) satellite cells was greater on fibers that had received gentle agitation during collagenase digestion than on those that were subject to digestion without agitation during isolation. The findings are interpreted to mean that at least some of the variation among published reports may derive from the application of various methods of fiber isolation. The information should be useful for maintaining satellite cell quiescence during studies of the regulatory steps that lead to satellite cell activation.Key words: activation, skeletal muscle, proliferation, single-fiber culture, myogenesis.
Hypoxia inducible factor-1: regulation by nitric oxide in posthypoxic microvascular endothelium
Authors: Natarajan Ramesh , Jones Drew G , Fisher Bernard J , Wallace Timothy J , Ghosh Shobha , Fowler, III Alpha A
Published: October 2005

Microvascular endothelial cells provide a critical regulatory interface between blood constituents and tissue. Hypoxia inducible factor-1 (HIF-1) is a key transcription factor required for expression of hypoxia-dependent genes. We employed a model of hypoxia and reoxygenation (H/R) using the dermal microvascular endothelial cell line HMEC-1 to examine the effects of altered oxygen concentrations on microvascular HIF-1 expression and nitric oxide (NO) formation. Hypoxia increased inducible NO synthase (iNOS) mRNA in a time-dependent manner in HMEC-1. However, endothelial NO synthase mRNA progressively declined during hypoxia. H/R promoted significant increases in cellular nitrite levels that were significantly abrogated by the specific iNOS inhibitor N6-(1-iminoethyl)-L-lysine, di hy drochloride. Exogenous NO promoted stabilization of the alpha subunit of HIF-1 and produced functional DNA binding. Exposure of HMEC-1 to H/R resulted in previously unrecognized biphasic HIF-1α stabilization during reoxygenation. When the iNOS gene was silenced through the use of iNOS-specific small interfering RNA, HIF-1α stabilization and HIF-1 activation were dramatically diminished, suggesting that inducible NOS-derived NO is a key factor sustaining HIF-1 activation during both hypoxia and reoxygenation.Key words: hypoxia, nitric oxide, reoxygenation, microvascular endothelium, HIF-1.
Characterization of murine monoclonal antibodies againstHelicobacter pylorilipopolysaccharide specific for Lexand Leyblood group determinants
Authors: Altman Eleonora , Harrison Blair A , Hirama Tomoko , Chandan Vandana , To Rebecca , MacKenzie Roger
Published: October 2005

The cell envelope of Helicobacter pylori contains lipopolysaccharide (LPS), the O-chain of which expresses type 2 Lexand Leyblood group antigens, which mimic human gastric mucosal cell-surface glycoconjugates and may contribute to the survival of H. pylori in gastric mucosa. Here we describe the generation of monoclonal antibodies specific for Lexand Leyblood group determinants and the characterization of their binding properties using purified, structurally defined H. pylori LPS, synthetic glycoconjugates, and H. pylori cells. Analysis of oligosaccharide binding by SPR provided a rapid and reliable means for characterization of antibody affinities. One of the antibodies, anti-Lex, was of IgG3 subclass and had superior binding characteristics as compared with the commercially available anti-LexIgM. These antibodies could have potential in the immunodiagnosis of certain types of cancer, in serotyping of H. pylori isolates, and in structure–function studies.Key words: Helicobacter pylori, lipopolysaccharide, monoclonal antibodies, Lewis determinants, immunodiagnosis.
Lymphoid signal transduction mechanisms linked to cellular prion protein
Authors: Mazzoni I E , Ledebur, Jr. H C , Paramithiotis E , Cashman N
Published: October 2005

The normal cellular isoform of the prion protein (PrPC) is a glycosylphosphatidylinositol-anchored cell surface protein that is expressed widely, including in lymphoid cells. We compared lectin-induced mitogenesis and selected cell signaling pathways in splenocytes from wild-type BALB/c mice and Zrch Prnp0/0(PrP0/0) mice bred on a BALB/c background for more than 10 generations.3H-thymidine incorporation induced by concanavalin A (Con A) or phytohemagglutinin (PHA) was significantly reduced in PrP0/0splenocytes, most prominently early in activation (24 and 48 h). Con A activation in PrP0/0splenocytes was associated with differences in the phosphorylation (P) patterns of protein kinase C (PKC α/β, but not δ) and the PKC downstream effectors p44/42MAPK (mitogen-activated protein kinase). P-PKC and P-MAPK profiles were similar in wild-type and PrP0/0splenocytes following PMA treatment, indicating that the ability of these 2 enzymes to be phosphorylated is not impaired in the absence of PrPC. Con A-induced calcium fluxes, monitored by indo-1 fluorescence, were equivalent in PrP0/0and PrP+/+splenocytes, suggesting that calcium-dependent mechanisms are not directly implicated in the differential phosphorylation patterns or mitotic responses. Our data indicate that PrP0/0splenocytes display defects in upstream or downstream mechanism(s) that modulate PKCα/β phosphorylation, which in turn affects its capacity to regulate splenocyte mitosis, consistent with a role for PrPCin immune function.Key words: PKC, MAPK, mitosis, bovine spongiform encephalopathy, Creutzfeldt-Jacob disease.
Blueberry flavonoids inhibit matrix metalloproteinase activity in DU145 human prostate cancer cells
Authors: Matchett Michael D , MacKinnon Shawna L , Sweeney Marva I , Gottschall-Pass Katherine T , Hurta Robert A.R
Published: October 2005

Regulation of the matrix metalloproteinases (MMPs), the major mediators of extracellular matrix (ECM) degradation, is crucial to regulate ECM proteolysis, which is important in metastasis. This study examined the effects of 3 flavonoid-enriched fractions (a crude fraction, an anthocyanin-enriched fraction, and a proanthocyanidin-enriched fraction), which were prepared from lowbush blueberries (Vaccinium angustifolium), on MMP activity in DU145 human prostate cancer cells in vitro. Using gelatin gel electrophoresis, MMP activity was evaluated from cells after 24-hr exposure to blueberry fractions. All fractions elicited an ability to decrease the activity of MMP-2 and MMP-9. Of the fractions tested, the proanthocyanidin-enriched fraction was found to be the most effective at inhibiting MMP activity in these cells. No induction of either necrotic or apoptotic cell death was noted in these cells in response to treatment with the blueberry fractions. These findings indicate that flavonoids from blueberry possess the ability to effectively decrease MMP activity, which may decrease overall ECM degradation. This ability may be important in controlling tumor metastasis formation.Key words: blueberry flavonoids, MMP activity, prostate cancer cells.
The roles of the human lipid-binding proteins ORP9S and ORP10S in vesicular transport
Authors: Fairn Gregory D , McMaster Christopher R
Published: October 2005

Inactivation of the yeast oxysterol binding protein related protein (ORP) family member Kes1p allows yeast cells to survive in the absence of Sec14p, a phospholipid transfer protein required for cell viability because of the role it plays in transporting vesicles from the Golgi. We expressed human ORP9S and ORP10S in yeast lacking Sec14p and Kes1p function, and found that ORP9S completely complemented Kes1p function, whereas ORP10S possessed only a weak ability to replace Kes1p function. Purified ORP9S protein bound several phosphoinositides, whereas ORP10 bound specifically to phosphatidylinositol 3-phosphate. The combined evidence demonstrates that only a subset of human ORP proteins can function as negative regulators of Golgi-derived vesicular transport.Key words: phospholipid, Saccharomyces cerevisiae, Golgi, vesicular transport, oxysterol binding protein related protein.
The association between RhoB and caspase-2: changes with lovastatin-induced apoptosis
Authors: Kong Jennifer Y , Rabkin Simon W
Published: October 2005

Because cytoskeletal actin is regulated, in part, by Rho, and because Rho and caspases are involved in apoptosis, we sought to determine whether there was an association between RhoB and caspase-2. A RhoB–caspase-2 association was consistently demonstrated in neonatal mouse cardiomyocytes with Western Blotting, either after im mun o precipitation with RhoB followed by immunoblotting with caspase-2, or in reciprocal experiments after immuno precipitation with caspase-2 and immunoblotting with RhoB (n = 14). Although the RhoB–caspase-2 complex was constitutively present, the link between RhoB and caspase-2 may be operative in apoptosis because the HMG-CoA reductase inhibitor lovastatin increased the RhoB–caspase complex, especially in the nuclear fraction of the cell, with a peak occurrence 2 h after treatment. This association was unaffected by the caspase-2 inhibitor zVDVAD. Lovastatin produced apoptosis that was accompanied by an activation of caspase-2, as demonstrated by its immunohistochemistry and by the fact that the caspase-2 inhibitor zVDVAD reduced lovastatin-induced apoptosis. Lovastatin induced dramatic changes in cell morphology and a reduction in F-actin. Immunoblotting for actin suggests that lovastatin does not induce a degradation of the actin molecule, but rather affects filamentous F-actin. Caspase-2 inhibition with zVDVAD reduced lovastatin-induced alteration in cytoskeletal F-actin. The Rho inhibitor, Clostridium difficile toxin B, blunted the ability of lovastatin to induce apoptosis. In summary, these data show a previously unrecognized association between RhoB and caspase-2 in the cytosolic and nuclear fractions, which has ramifications for processes regulated by RhoB and caspase-2, including apoptosis.Key words: actin, apoptosis, caspase-2, cardiomyocyte, heart, lovastatin.
Cold-temperate climate: a factor for selection of ammonia oxidizers in upland soil?
Authors: Avrahami Sharon , Conrad Ralf
Published: October 2005

Ammonia-oxidizing bacteria in various upland soils show a rather large diversity with respect to their amoA genes (coding for a subunit of the ammonium monooxygenase). It is known that the community structure of ammonia-oxidizing bacteria in upland soils is influenced by different selective factors, such as pH, gravimetric water content, fertilizer treatment, and temperature. The question, from an ecological point of view, is whether a particular ecophysiological factor, such as temperature, could select for a particular community structure of ammonia oxidizers in upland soils that would be represented by distinct clusters of the amoA gene (AmoA cluster). Studying the literature, including recent publications and our own unpublished results, we found that AmoA clusters 3a, 3b, and 9–12 apparently exhibited no preference for either subtropical/tropical soils (i.e., warm regions) or temperate cold soils. However, AmoA clusters 1 and 4 (and perhaps cluster 2) seem to occur predominantly in soils from cold-temperate regions. Here we review the evidence for a temperature effect on the global distribution of amoA genes in warm- and cold-temperate soils.Key words: nitrifying bacteria, ammonia-oxidizing bacteria, Nitrosospira, ammonium monooxygenase gene, amoA.
Applying a most probable number method for enumerating planktonic, dissimilatory, ammonium-producing, nitrate-reducing bacteria in oil field waters
Authors: Eckford Ruth E , Fedorak Phillip M
Published: October 2005

A most probable number (MPN) method was used to enumerate dissimilatory ammonium-producing, nitrate-reducing bacteria (DAP-NRB) in oil field waters and to determine whether they were stimulated by nitrate addition used to control hydrogen sulfide production. An ammonium production medium with 5 carbon and energy sources (acetate, glucose, glycerol, pyruvate, and succinate) and nitrate was used in a 3-tube MPN procedure to enumerate DAP-NRB. These bacteria were detected in 12 of 18 oil field water samples, but they were seldom detected in wellhead samples. Three oil field water samples were amended with nitrate in serum bottles and the numbers of different NRB were determined over a 38-day incubation time. This amendment stimulated increases in the numbers of heterotrophic NRB and autotrophic nitrate-reducing, sulfide-oxidizing bacteria, but DAP-NRB remained a minor portion of these communities. Overall, DAP-NRB were present in many of the oil field waters that were examined but their numbers were low. It appears that DAP-NRB would play a minor role in the consumption of nitrate injected into oil field waters for the control of hydrogen sulfide production.Key words: heterotroph, nitrate-reducing bacteria, dissimilatory nitrate reduction, ammonium, petroleum.
The role of clp-regulated factors in antagonism against Magnaporthe poae and biological control of summer patch disease of Kentucky bluegrass by Lysobacter enzymogenes C3
Authors: Kobayashi Donald Y , Yuen Gary Y
Published: October 2005

A global regulator was previously identified in Lysobacter enzymogenes C3, which when mutated, resulted in strains that were greatly reduced in the expression of traits associated with fungal antagonism and devoid of biocontrol activity towards bipolaris leaf-spot of tall fescue and pythium damping-off of sugarbeet. A clp gene homologue belonging to the crp gene family was found to globally regulate enzyme production, antimicrobial activity, and biological control activity expressed by Lysobacter enzymogenes C3 (Kobayashi et al. 2005). Here, we report on the expansion of the biocontrol range of L. enzymogenes C3 to summer patch disease caused by Magnaporthe poae. The clp– mutant strain 5E4 was reduced in its ability to suppress summer patch disease compared with the wild-type strain C3 and was completely devoid of antifungal activity towards M. poae. Furthermore, cell suspensions of 5E4 were incapable of colonizing M. poae mycelium in a manner that was distinct for C3. Strain C3 demonstrated biosurfactant activity in cell suspensions and culture filtrates that was associated with absorption into the mycelium during the colonization process, whereas 5E4 did not. These results describe a novel interaction between bacteria and fungi that intimates a pathogenic relationship.Key words: lytic enzymes, biosurfactant, turfgrass biocontrol agent, mycopathogenic bacteria.
ESTIMATIONS FOR A SIMPLE STEP-STRESS MODEL WITH PROGRESSIVELY TYPE-II CENSORED DATA
Authors: WU SHUO-JYE , LEE HSIU-MEI , CHEN DAR-HSIN
Published: October 2005

With today's high technology, some life tests result in no or very few failures by the end of test. In such cases, an approach is to do life test at higher-than-usual stress conditions in order to obtain failures quickly. This study discusses the point and interval estimations of parameters on the simple step-stress model in accelerated life testing with progressive type II censoring. An exponential failure time distribution with mean life that is a log-linear function of stress and a cumulative exposure model are considered. We derive the maximum likelihood estimators of the model parameters. Confidence intervals for the model parameters are established by using pivotal quantity and can be applied to any sample size. A numerical example is investigated to illustrate the proposed methods.
TOLERANCE DESIGN THROUGH VARIANCE TRANSMISSION EQUATIONS
Authors: FENG QIANMEI , KAPUR KAILASH C.
Published: October 2005

The quality of a system for any given function is affected by the variability of the output response related to that function. The variation of the output response is typically an aggregate of many variations from components of the system. In order to study how the variation of the components is transmitted to the output response, it is desirable to derive variance transmission equation (VTE) that describes the variance structure between components and the response. Based on the availability of system transfer function (STF) for a given function or application, three approaches are discussed to develop the variance transmission equation: Taylor series approximation, response surface model, and design of experiments methods. The developed variance transmission equation is incorporated in the tolerance design model that is used to find an economic balance between the desired quality and the cost associated with variance. Using a case study for a passive filter network, we illustrate how to improve the quality of a device using tolerance design through variance transmission equation. The results demonstrate the quality improvement of the system using the proposed economic optimization model.
DC-DC CONVERTER RELIABILITY: DESIGN, COMPONENTS AND QUALIFICATION
Authors: TIAN XIJIN
Published: October 2005

This paper provides a comprehensive study on reliability issues related to DC-DC converter design. First of all, some common reliability issues and DC-DC converter design topologies are discussed. Then, a reliability sensitivity study results on an industry standard VRM is presented using a prediction-based design-for-reliability and sensitivity analysis tool created by the author and colleagues at HP. The thermal design issues and component derating in the converter design are discussed. Since electronic component reliability has been a bottleneck in DC-DC converter reliability, the component reliability issues are discussed and some reliability application guidelines are also provided for the DC-DC converters reliability design. In the last part of the paper, an integrated reliability testing, qualification, and quality control procedure is presented using highly accelerated testing methodology. The use of this procedure by HP on DC-DC converter reliability and quality control has shown promising results.
ASYMPTOTIC BEHAVIOR OF STRUCTURES MADE OF PLATES
Authors: GRISO GEORGES
Published: October 2005

The aim of this paper is to study the asymptotic behavior of a structure made of plates of thickness 2δ when δ → 0. This study is carried out within the frame of linear elasticity by using the unfolding method. It is based on several decompositions of displacements of the structure and on the passing to the limit in fixed domains.

We begin by studying the displacements of a plate. We show that any displacement is the sum of an elementary displacement concerning the normal lines on the middle surface of the plate and a warping. An elementary displacement is linear with respect to the variable x3. It is written [Formula: see text] where [Formula: see text] is a displacement of the mid-surface of the plate. We show a priori estimates and convergence results when δ → 0. We characterize the limits of the unfolded displacements of a plate as well as the limits of the unfolded strained tensor.

Then, we extend these results to structures made of plates. We show that any displacement of a structure is the sum of an elementary displacement of each plate and of a residual displacement. The elementary displacements of the structure (e.p.s.d.) coincide with elementary rod displacements in the junctions. Any e.p.s.d. is given by two functions belonging to H1( S ; ℝ3) where S is the skeleton of the structure (the set formed by the mid-surfaces of the plates constituting the surface). One of these functions, [Formula: see text], is the skeleton displacement. We show that [Formula: see text] is the sum of an extensional displacement and of an inextensional one. The first one characterizes the membrane displacements and the second one is a rigid displacement in the direction of the plates and it characterizes the flexion of the plates.

Eventually, we pass to the limit as δ → 0 in the linearized elasticity system. On the one hand, we obtain a variational problem that is satisfied by the limit extensional displacement, and on the other hand, a variational problem satisfied by the limit of inextensional displacements.
CO-EVOLVING BUSINESS MODELS: A CASE STUDY WITH THE INTERNET SERVICE PROVIDER (ISP) INDUSTRY
Authors: FENTY IAN , BONABEAU ERIC , BRANKE JUERGEN
Published: October 2005

In this paper, co-evolution is used to examine the long-term evolution of business models in an industry. Two types of co-evolution are used: synchronous, whereby the entire population of business models is replaced with a new population at each generation, and asynchronous, whereby only one individual is replaced.
AN OVERVIEW ON THE CONSTRUCTION OF FUZZY SET THEORIES
Authors: PRADERA ANA , TRILLAS ENRIC , RENEDO ELOY
Published: October 2005

This paper analyzes the main issues involved in the construction of Fuzzy Set Theories. It reviews both standard solutions (based on the well-known triangular norms and conorms) as well as less the conventional proposals that provide alternative views on, for example, the definition of fuzzy connectives or the study of their properties.
INTERPRETING CHANCE FOR COMPUTER SECURITY BY VITERBI ALGORITHM WITH EDIT DISTANCE
Authors: KOO JA-MIN , CHO SUNG-BAE
Published: October 2005

This paper addresses the importance of chance discovery in computer security. There are various methods to discover chances in computer usage, but they have such drawbacks as discovering only anomalies, not interpreting anomalies in conventional approach in the community of computer security. This paper focuses on a role of interpreting the type of anomalies by analyzing the state sequences using Viterbi algorithm and evaluating the distance between the standard model of anomaly type and the state sequence of discovered anomalies. Because the state sequences are not always extracted consistently due to environmental factor, the edit distance is utilized to measure the distance effectively. Experimental results show the possibility of the proposed method in computer security.
Preparation and Characterization of BaTiO3 Thick Films with Li2O-SiO2 Sintering Aid
Authors: Nakaiso Toshiyuki , Kageyama Keisuke , Ando Akira , Sakabe Yukio
Published: October 2005

The effect of adding a Li2SiO3 (LSO) sintering aid for low temperature fabrication of BaTiO3 (BT) thick films was investigated. LSO-added BT thick films were prepared by the screen printing method on Pt-coated ZrO2 substrates. Their sintering properties were significantly improved by the addition of LSO, and the relative density of the BT thick film fired in air at 1200°C was 96%. The secondary phase was not observed. The dielectric, ferroelectric, and piezoelectric properties of the LSO-added BT thick films were examined. A typical ferroelectric hysteresis loop was observed, and the remnant polarization (P
r) was 7.5 µC/cm2. The dielectric constant was 3200, and tan
δ was 2.1%. The maximum piezoelectric constant d
31 calculated from the displacement of the Pt/BT/Pt/ZrO2 monomorph cantilever was -140 pm/V, and d
33 measured with an atomic force microscope was 320 pm/V.
Electrical Properties and Microstructures of Sol-Gel-Deposited Lead Zirconate Titanate Thin Films Crystallized by 28 GHz Microwave Irradiation
Authors: Wang Zhan Jie , Kokawa Hiroyuki , Takizawa Hirotsugu , Ichiki Masaaki , Maeda Ryutaro
Published: October 2005

Pb(Zr
x
Ti1-x
)O3 (PZT) thin films were coated on Pt/Ti/SiO2/Si substrates by a sol-gel method and then crystallized by 28 GHz microwave irradiation. The crystalline phases and microstructures as well as the electrical properties of the microwave-irradiated PZT films were investigated as a function of the elevated temperature generated by microwave irradiation. X-ray diffraction analysis indicated that the PZT films crystallized well into the perovskite phase at an elevated temperature of 480°C by microwave irradiation. Scanning electron microscopy images showed that the films had a granular grain structure and most of the grains were approximately 1.5 µm in size. With increasing elevated temperature from 480°C to 600°C by microwave irradiation, the breadth of grain boundaries of the films became narrow and the remanent polarization of the films increased slightly. It is clear that microwave irradiation is effective for obtaining well-crystallized PZT films with good properties at low temperatures in a short time.
Dielectric Characteristics of Ferroelectric Films Prepared by Aerosol Deposition in THz Range
Authors: Nakada Masafumi , Ohashi Keishi , Akedo Jun
Published: October 2005

The dielectric properties of lead titanate [PbTiO3] and lanthanum-modified lead zirconate titanate [PLZT, Pb0.91La0.09(Zr0.65Ti0.35)O3] films, prepared by aerosol deposition (AD), were measured in the frequency range from 100 GHz to 10 THz and in the kHz range. THz time-domain spectroscopy was applied for measurement in the wavenumber range from 4 cm-1 to 70 cm-1, and far-infrared Fourier transform measurements from 70 cm-1 to 700 cm-1 was carried out. We observed that the dielectric constants change smoothly from kHz to THz ranges for the as-deposited PbTiO3 film, indicating that the as-deposited PbTiO3 film exhibits no dielectric dispersion due to domain wall motions. The value of the real part of the dielectric constants in the kHz range increased with annealing, suggesting the appearance of Debye relaxation by annealing. We found that the real parts of the dielectric constants of the AD-PLZT films in the kHz range were one order of magnitude smaller than those of bulk PLZT ceramics, while the dielectric responses in the THz range, which were determined by phonon modes, were comparable to those of bulk ceramic PLZT. The structure of AD-PLZT film, which consists of grains of about 20 nm in size, may affect the motion of polar nanoregions, resulting in a low dielectric response in the low frequency range.
Preparation and Photovoltaic Properties of Lead Lanthanum Zirconate Titanate in Design of Multilayers
Authors: Ichiki Masaaki , Maeda Ryutaro , Morikawa Yasushi , Mabune Yousuke , Nakada Takeshi , Nonaka Kazuhiro
Published: October 2005

In this paper, we report on the formation of multilayer structures and the highly improved photovoltaic output current of the lead lanthanum zirconate titanate (PLZT) film employed. The photovoltaic effect of ferroelectrics has the advantage of simple mechanisms of nonbias applications, which are indispensable for semiconductor p-n junctions. However, the output current of PLZT bulk is too low for use as a device current source. The new design is described using an upper transparent indium tin oxide (ITO) electrode. The PLZT film structure exhibits a µA output current upon light illumination. The photovoltaic current of the PLZT film is more than 102times that of the bulk PLZT. These differences are due to the characteristics of the design of multilayers including the configuration of the electrode. The PLZT film also has the advantages of easy output control and suitability for use on a Si substrate. A simple model is used for an illustrative explanation of the improved photovoltaic effect of the PLZT film. Results show that the photovoltaic effect of the ferroelectric multilayer is useful as the current source for a micro-electro-mechanical system (MEMS).
Dependences of Process-Induced Damage on Imprint Characteristics in SrBi2Ta2O9 Capacitors
Authors: Ashikaga Kinya , Takaya Koji , Kanehara Takao , Koiwa Ichiro
Published: October 2005

We investigated hysteresis shifts in SrBi2Ta2O9 capacitors during high-temperature storage in an attempt to understand the mechanism underlying imprint degradation. We found that the activation energy (E
a) of imprint degradation is derived from the temperature dependence of the hysteresis shift, but is almost independent of the size of the capacitors (about 0.2 eV). On the other hand, E
a is strongly dependent on the size of contact areas on the upper electrodes of the capacitors (0.1 to 0.2 eV). This result suggests that imprint degradation is mainly due to the characteristics of ferroelectric-electrode interfaces, and is not due to the edges of the capacitors. We reached this conclusion because the dependence on the contact areas is related to process-induced damage near the upper electrode.
Polarization and Leakage Degradation of Pt/SrBi2Ta2O9/Pt Capacitors and Their Recovery
Authors: Tamai Shin-ichi , Maeda Yoshihito , Kobayashi Hiroyuki
Published: October 2005

Water (H2O) vapor-induced degradation of SrBi2Ta2O9 (SBT) capacitors has been investigated. SBT capacitors with no passivation layer were maintained in the atmosphere at 20°C for one-half year after their preparation. The capacitors showed pronounced degradation of polarization and increased leakage currents. A recovery process based on H2O vaporization from the SBT films was examined. We succeeded in completely recovering the polarization, fatigue and leakage current characteristics using thermal annealing at 300°C in a vacuum.
Synthesis and Properties of Intergrown Bi4Ti3O12-SrBi4Ti4O15 Ferroelectric Thin Films by Chemical Solution Deposition
Authors: Sakamoto Wataru , Imada Keiichi , Shimura Tetsuo , Yogo Toshinobu
Published: October 2005

Ferroelectric Bi4Ti3O12-SrBi4Ti4O15 (BiT-SBTi)-based thin films have been prepared by chemical solution deposition. Homogeneous and stable precursor solutions were prepared by controlling the reaction of starting metalorganic compounds in a solution. BiT-SBTi precursor films crystallized in the desired intergrown BiT-SBTi single phase on Pt/TiOx/SiO2/Si substrates if several processing conditions were optimized. To improve the ferroelectric properties of resultant films, the effect of Nd substitution at Bi sites in BiT-SBTi on the crystallization, the surface morphology and the ferroelectric properties was examined. BiT-SBTi thin films with an optimum amount of Nd substitution exhibited ferroelectric properties and demonstrated a 2Pr value larger than 30 µC/cm2. The surface morphology of synthesized thin films was also improved by controlling the amount of Nd substitution in BiT-SBTi.