bluuebunny/crossref_metadata_2025 huggingface dataset:
Whirling of a base-excited cantilever beam
Authors: Hyer Michael W.
Published: October 2005

The paper describes the response of a thin elastic cantilever beam excited by a known harmonic displacement at its base. The principal moments of the beam cross-sectional area are equal and the base excitation is in one of the principal directions. If the excitation frequency is slightly less than the resonant frequency of one of the bending modes, planar motions of the beam are unstable and an out-of-plane component of displacement develops. With this motion, the free end of the beam moves in an ellipse while the base motion is planar. Increasing the frequency to a value just above resonance causes the motion to become planar again. This whirling is a result of nonlinear coupling between the in-plane and out-of-plane displacements through the axial inertia. The paper presents the governing equations, develops the frequency–amplitude relations for the whirling response and examines the stability of the response. It is shown all whirling motions are stable and the frequency range for which whirling occurs increases with the level of excitation. Also it is shown for a given level of excitation, the frequency range broadens with increasing mode number.
Performance estimates for the Hunt transit detector
Authors: Curry Thomas J. , Tufts Donald W.
Published: October 2005

We present principles for the design of a transit detector first proposed by F. V. Hunt. These principles permit the designer to specify the parameters of the transit detector, and to predict its performance without resorting to experimentation with time scaled models. It is shown that making simple approximations to the transit signal shape, constraining the observation time of the system to the effective duration of the transit, and applying a Gaussian approximation to the output of the system, leads to the specification of filter averaging times and accurate prediction of performance. Some variations of the scheme proposed by Hunt are briefly compared.
Acoustical and perceptual characteristics of speech produced with an electronic artificial larynx
Authors: Weiss Michael S. , Yeni-Komshian Grace H. , Heinz John M.
Published: October 2005

Five normal-speaking adult males were taught to produce speech using an electrolarynx. Speech phoneme intelligibility was measured in a closed-set word discrimination test and through phonetic transcriptions of the spoken materials. Mean percentages of correct identification for the five talkers were 90% and 57% for the word-identification test and phonetic transcription, respectively. An analysis of perceptual confusions revealed that errors were most frequently associated with the voicing feature and that few manner or place of articulation errors occurred. Over the range of variables observed, the intensity of both the speech and the noise radiating directly from the electrolarynx, the spectrum of the radiated noise and speaking rate were not found to be determinants of intelligibility.
Ultrasonic absorption in liver tissue
Authors: Frizzell Leon A. , Carstensen Edwin L. , Davis Jeffrey D.
Published: October 2005

Ultrasonic attenuation coefficients were measured in mammalian liver for frequencies ranging from 0.5 to 10 MHz and for a range of sample preparations. Certain preparative procedures were found to greatly increase the low-frequency attenuation coefficient due to the introduction of bubbles into the sample. The low-frequency attenuation was reduced by storage at low temperatures or by pressurization, each caused the bubbles to go into solution, resulting in an attenuation coefficient that was a simple power function of frequency. Absorption coefficients of in vitro and in vivo samples were found to be similar and to show much less dependence on sample preparation than the attenuation measurements. These studies suggest that properties of carefully prepared in vitro samples are indicative of the in vivo properties.
The application of capacitive transducers to sound velocity measurements in TTF-TCNQ
Authors: Tiedje T. , Haering R. R. , Hardy W. N.
Published: October 2005

A capacitive technique is described for measuring the elastic properties of small samples. Acoustic resonance modes of the sample are excited electrostatically and detected with a detector capacitor which is biased with a uhf carrier signal. The sensitivity of the detection scheme is investigated theoretically. An application of the technique to the measurement of three elastic constants (Ea, Eb, and c66) of single crystals of TTF-TCNQ is described.
Reflection coefficient for a lossy liquid–lossless isotropic solid interface
Authors: Atalar Abdullah
Published: October 2005

A theoretical treatment of the reflection problem at a lossy liquid–lossless isotropic solid is given. The calculation results indicate that the reflection coefficient has a peak greater than unity. A physical explanation is proposed which also leads to the prediction that at some critical liquid attenuation a Rayleigh wave propagating on the solid surface will not leak into the liquid.
Causality correlation analysis of flow noise with fluid dilatation as source fluctuation
Authors: Rackl R. , Siddon T. E.
Published: October 2005

A recently developed diagnostic technique for aerodynamic noise involves cross correlation between various types of source quantities and the radiated sound [T. E. Siddon, 7th ICA (1971)]. The technique is applied to a circular jet where—following H. S. Ribner’s dilatation model—the turbulent pressure is viewed as the basic source fluctuation (the ’’cause’’), and is cross correlated with the radiated acoustic pressure (the ’’effect’’). The cause–effect principle is applied in real time. This led to the adoption of the term ’’causality’’ correlation. Information on the volume distribution of source strength, the spectrum from unit volume, and the local correlation volume can, in principle, be obtained by moving a specially designed pressure sensor around the jet. The pressure sensor is of an airfoil type, designed to minimize the projected area in the direction of radiation, and thereby the additional noise from the interaction of the turbulence with the sensor. Also, pressure measurement errors due to turbulent interference are reduced substantially with respect to those for classical cylindrical pressure probes. By integrating the radial distribution of source strength a ’’slice-wise’’ axial distribution is obtained; it is in qualitative agreement with results of other researchers. However, on integrating the axial distribution along the entire jet, the resulting total sound level was found to be substantially larger than that obtained by direct measurement. This paradox is explained as a consequence of spurious drag dipole radiation from the stem of the probe.
Subjective loudness of simulated quarry blast waves, with implications for the transition from impulsive to continuous sound
Authors: Niedzwiecki A. , Ribner H. S.
Published: October 2005

The tradeoff between amplitude and duration for equal loudness was explored for idealized quarry blast waves. An extended low-frequency response loudspeaker-driven simulation booth was employed with computer-generated input test signals. In place of actual irregular blast waves, the simulated signatures were composed of sequences of identical shock-decay impulses of 25 ms duration and 0.2 ms rise time. Sequences of 1–16 impulses yielded overall durations of 25–400 ms. At the short durations the loudness was found to increase 2 dB for each doubling of duration; above 100 ms the increase was progressively lower, approaching as an asymptote the level for continuous sound. The results were compared with theoretical predictions: for this purpose the spectral method of Johnson and Robinson, well verified in our earlier studies of sonic boom impulses, was used. The shorter quarry blast judgments (T?100 ms) were found to be in very good agreement in terms of relative loudness levels. With an ad hoc—but physically plausible—modification (including adjustment of the critical integration time of the ear) the predictive method was extended to encompass the long duration signals as well. Thus the applicability of the method has been demonstrated for other types of transient sounds than the N wave; and the extension of the method tentatively appears to bridge the range between impulsive and continuous sounds of similar spectral content.
Selective adaptation to frequency-modulated tones: Evidence for an information-processing channel selectively sensitive to frequency changes
Authors: Regan D. , Tansley B. W.
Published: October 2005

Exposure to an FM tone elevates FM threshold but not AM threshold. This holds for a wide range of frequency deviations (ΔF=±0.4 Hz–±30 Hz at least) provided that modulation frequency is low (fm=2 Hz), but if fm is somewhat higher (e.g., 8 Hz) the finding only holds for small frequency deviations. FM threshold can rise with time up to an adapting duration of at least 1200 s, though this buildup depends on frequency deviation. Exposure to an AM tone elevates AM threshold, but not FM threshold, over a wide range of modulation depths (at least m=5%–50%). Quasi-FM (QFM) adapting tones resemble FM adapting tones in their effects upon FM and AM sensitivities, even though QFM and AM adapting tones have identical power spectra. Exposure to a pure tone produces no difference between FM and AM threshold elevations. These data can be explained if the human auditory pathway contains separate information-processing channels for AM and FM signals whose sensitivities do not overlap even with suprathreshold stimuli. We suppose that the FM channel (but not the AM channel) is sensitive to changing differences (or ratios) between signals from different sites along the basilar membrane.
A means for computing the Kirchhoff surface integral for a disk radiator as a single integral with fixed limits
Authors: Archer-Hall J. A. , Bashter A. I. , Hazelwood A. J.
Published: October 2005

The evaluation of the Kirchhoff integral giving the acoustic field due to one surface of an unbaffled disk radiator has been carried out using cylindrical polar coordinates with a moveable origin. This system makes it possible to covert a fairly complicated surface double integral to a single integral with fixed limits for the purpose of computation.
Maximum sound pressure from a displacement limited circular piston
Authors: Butler John L.
Published: October 2005

The criterion for the maximum farfield pressure at a beam angle ϑ0 for a displacement limited circular piston transducer is developed. It is shown that for this case the wavelength to piston diameter ratio is 1.3064 sin ϑ0. This leads to the result that maximum pressure will occur in a hemispherical region if the piston diameter is slightly greater than three-fourths of a wavelength. The suggestion of such a possibility was made by Frank Massa, which led the author to the mathematical proof presented in this letter.
Determination of the radii of gas cavitation nuclei by filtering gelatin
Authors: Yount David E. , Yeung Chick M. , Ingle Frank W.
Published: October 2005

We report an experiment in which the size distributions of the entities which initiate bubble formation in supersaturated gelatin are systematically altered by passing test samples through Nuclepore filters with nominal pore diameters of 0.4, 0.6, 0.8, 1.0, and 3.0 μm. The actual diameters range from +0% to −20% of the nominal values. The data are compared with a new model, described in the previous article, in which gas cavitation nuclei are stabilized by surface-active skins of varying gas permeability. Within the measurement resolution, the initial cutoff radii for bubble formation are the same as the respective filter-pore radii. This implies that the calculated radii are those of actual physical structures capable of initiating bubble formation in gelatin.
Knock-induced cavity resonances in open chamber diesel engines
Authors: Hickling R. , Feldmaier D. A. , Sung S. H.
Published: October 2005

Knock is known to cause acoustical cavity resonances in the combustion chambers of engines. Understanding this phenomenon is important for control of engine noise and optimization of knock-detection systems. Cavity resonances were investigated in detail for six open-chamber diesel engines of different sizes. Spectral data were obtained from cylinder pressure-time traces and compared with predictions from finite-element calculations of the cavity resonances. Good agreement was found.
A Volterra functional expansion for the logarithm of the likelihood ratio for detection of a memoryless nonlinear functional of a random process in Gaussian white noise
Authors: Kenefic R. , Nuttall A. , Weiner D.
Published: October 2005

A Volterra functional expansion for the logarithm of the likelihood ratio, for detection of a memoryless nonlinear functional of a random process in Gaussian white noise, is presented. For the special case of detection of a zero-mean Gaussian process in Gaussian white noise, it is shown that the Volterra expansion reduces to well-known results. An approximation to the Volterra expansion is suggested for some problems with periodic nonlinearities.
A standing-wave tube as an absolutely known source of sound power
Authors: Cook Richard K. , Proctor Thomas M.
Published: October 2005

An open ended standing-wave tube has been examined as an absolute sound power (ASP) source, having an absolutely known radiated sound power. The ASP source can serve as an acoustical instrument, principally in reverberation chambers, for three purposes. The first is for calibration of the presently used arrays of microphones for measurement of total radiated sound power by steady sources. The second is for measurement of the influence of acoustical diffusion devices, such as moving vanes, on the radiated power of a source. A third application is to the steady-state measurement of the total cross section for sound absorption. The power measurement scheme makes use of concurrent measurements of sound pressure, both amplitude and phase, at two separate points inside the tube and on its axis. From these, the time-averaged product (Umov vector) of the particle velocity and pressure can be obtained. The product gives accurately both the sound intensity within the tube and the radiated power from the open end. Optimum accuracy for measurement of intensity is achieved by large microphone separations (one-quarter wavelength). Comparison of indicated sound power radiated from the tube with the usual sound power measurements done in both an anechoic and a reverberant environment are made.
An onionskin composite as a transducer backing material
Authors: Behrens John A. , Blankenship George W. , Stokes Robert H.
Published: October 2005

This paper describes the use of an onionskin composite for the backing material of piezoceramic elements in a high-frequency transducer array. It is the purpose of this paper to cite certain advantages of using this particular composite over a more rigid type material. Measurements on experimental test arrays consisted of single-stave directivity patterns and receiving sensitivity versus hydrostatic pressure. In order to show that a sonar array performance can be affected by the piezoceramic backing material, calculated array pattern data, based upon measured and calculated single-stave patterns, are presented in tabular form. The fabrication technique of putting the onionskin on a curved-face housing is presented. In the process, the composite is precompressed such that after being potted in polyurethane, the array will withstand high hydrostatic pressures without an extreme degradation in the sound isolating, tuning, and reflecting properties of the array.
A statistical theory for sound radiation and reflection from a duct
Authors: Cho Y. C.
Published: October 2005

A new analytical method is introduced for the study of the sound radiation and reflection from the open end of a duct. The sound is thought of as an aggregation of the quasiparticles—phonons. The motion of the latter is described in terms of the statistical distribution, which is derived from the classical wave theory. The results are in good agreement with the solutions obtained using the Wiener–Hopf technique when the latter is applicable, but the new method is simple and provides straightforward physical interpretation of the problem. Furthermore, it is applicable to a problem involving a duct in which modes are difficult to determine or cannot be defined at all, whereas the Wiener–Hopf technique is not.
Theory of the effect of stress on ultrasonic plane-wave reflectivity from a water–metal interface
Authors: Martin B. G.
Published: October 2005

Ultrasonic reflectivity from a solid is a function of longitudinal- and shear-wave velocities and attenuations, as well as the density. Using stress-dependent acoustic velocities obtained from second-order elasticity theory, we have calculated the plane-wave reflectivity at and near the Rayleigh critical angle for uniaxial stress. Reflectivity amplitude and phase results were obtained for both tensile and compressive stress. From the reflectivity amplitude data, values of Raleigh-wave velocity versus stress were obtained. The results exhibit the expected behavior and a comparison with such experimental data as are available shows fair agreement.
Scattering in an anisotropic random medium: Numerical calculations
Authors: Schwartz Nira , Beran Mark J.
Published: October 2005

The formulation of scattering of low-frequency acoustic radiation in an anisotropic random medium, like the ocean, results in an integro-differential equation for the coherence function. It was argued, however, that for horizontal scattering a more simplified differential equation is adequate. In this paper we demonstrate, by direct numerical calculation, that for a realistic case, this simplification is indeed appropriate and that the errors introduced are only of the order of a few percent. For vertical scattering in the absence of refraction, it is pointed out that a quasiasymptotic angular distribution results for large propagation distances in contrast to the exact asymptotic state that is predicted by the differential equation.
Acoustic scattering cross section predicted from an accurate model of the spectrum of temperature fluctuations
Authors: Hill R. J.
Published: October 2005

Recent theoretical and experimental advances have produced an accurate model of the power spectrum of temperature fluctuations in turbulent air. This model temperature spectrum and a semiempirical energy spectrum are used to predict the shape of the acoustic scattering cross section as a function of wavenumber and scattering angle. Experiments have shown that the temperature spectrum in air has a ’’bump’’ at high wavenumbers, and the model temperature spectrum shows that this feature is expected theoretically. A corresponding bump is predicted to appear in the acoustic scattering cross section. The bump in the cross section is reduced if velocity fluctuations dominate the scattering, because the energy spectrum has no bump. For typical energy dissipation rates in the atmospheric boundary layer, a 2-kHz acoustic sounder senses scattering attributable to the bump in the cross section. The amount of scattering attributable to the bump depends on the acoustic wavenumber and the microscale, and can be as much as 50% greater than the scattering predicted by the usual theoretical interpretation.
Multipole resonances in sound scattering from gas bubbles in a liquid
Authors: Sage K. A. , George Jacob , Überall H.
Published: October 2005

The acoustic scattering properties of spherical gas bubbles in a liquid differ from those of a pressure-release sphere by the well-known ’’giant’’ monopole resonance at very low frequencies, which is due to the compressibility of the gas contained in the bubble. We show here that, in addition to this monopole resonance, a large number of higher-frequency resonances exist which are either overtones of the monopole, or which correspond to both fundamental and overtones of bubble vibrations of higher multipolarity. Although much smaller in size than the giant monopole, these resonances may nevertheless constitute features of some importance in sound scattering from gas bubbles.
Comparison of fatalities from work related motor vehicle traffic incidents in Australia, New Zealand, and the United States
Authors: Driscoll T , Marsh S , McNoe B , Langley J , Stout N , Feyer A-M , Williamson A
Published: October 2005

Objective:To compare the extent and characteristics of motor vehicle traffic incidents on public roads resulting in fatal occupational injuries in Australia, New Zealand (NZ), and the United States (US).

Design and setting:Information came from separate data sources in Australia (1989–92), NZ (1985–98), and the US (1989–92).

Methods:Using data systems based on vital records, distributions and rates of fatal injuries resulting from motor vehicle traffic incidents were compared for the three countries. Common inclusion criteria and occupation and industry classifications were used to maximize comparability.

Results:Motor vehicle traffic incident related deaths accounted for 16% (NZ), 22% (US), and 31% (Australia) of all work related deaths during the years covered by the studies. Australia had a considerably higher crude rate (1.69 deaths/100 000 person years; 95% confidence interval (95% CI) 1.54 to 1.83) compared with both NZ (0.99; 95% CI 0.85 to 1.12) and the US (0.92; 95% CI 0.89 to 0.94). Industry distribution differences accounted for only a small proportion of this variation in rates. Case selection issues may have accounted for some of the remainder, particularly in NZ. In all three countries, male workers, older workers, and truck drivers were at higher risk.

Conclusions:Motor vehicle traffic incidents are an important cause of work related death of workers in Australia, NZ, and the US. The absolute rates appear to differ between the three countries, but most of the incident characteristics were similar. Lack of detailed data and inconsistencies between the data sets limit the extent to which more in-depth comparisons could be made.
Roller coaster related fatalities, United States, 1994–2004
Authors: Pelletier A R , Gilchrist J
Published: October 2005

Objective:To determine the number of fatalities related to roller coasters and examine factors common to multiple incidents.

Methods:A case was defined as the death of a person, which was associated with a roller coaster in the United States between 15 May 1994 and 14 May 2004. Cases were identified from four data sources: (1) Consumer Product Safety Commission, (2) Lexis-Nexis, (3) Medline, and (4) Saferparks.

Results:Forty people, ranging in age from 7 to 77 years, were killed in 39 separate incidents. Twenty nine (73%) deaths occurred among roller coaster patrons. Eleven fatalities resulted from external causes related to injuries from falls or collisions. Eighteen people died from medical conditions that might have been caused or exacerbated by riding a roller coaster; 15 were the result of intracranial hemorrhages or cardiac problems. Eleven (28%) deaths involved employees; all were caused by injuries.

Conclusions:Approximately four deaths annually in the United States are associated with roller coasters. Prevention of roller coaster fatalities is dependent on establishing an effective surveillance system for amusement ride injuries, engineering rides to better protect both patrons and employees, improving training and supervision of employees regarding safety precautions, and posting cautionary notices near roller coasters for people with specified medical conditions. Further research is needed on roller coaster related deaths resulting from intracranial hemorrhages and cardiac problems.
“Banned from the streets I have paid to use”: an analysis of Australian print media coverage of proposals for passenger and night driving restrictions for young drivers
Authors: Blows S , Ivers R Q , Chapman S
Published: October 2005

Objective:To catalogue arguments that can be anticipated in public debate when passenger and night driving restrictions are being advocated.

Design and setting:Frame analysis of all relevant coverage of these topics in Australian print media during the three month period between June and September 2004 when intensive debate on the topic occurred.

Main outcome measures:Debating frames used in reports and commentary on passenger and night driving restrictions.

Results:There were 52 relevant articles published containing seven distinct frames supporting the restrictions and six opposing them. Overall, more instances of frames supporting the restrictions were published; these mostly focused on the potential for saving lives. Opposition to the restrictions focused largely on their inappropriateness as a road safety measure as well as on the importance of young people’s autonomy and freedom.

Conclusions:Advocates of passenger and night driving restrictions have a number of arguments available to advance their case; however, it is important to anticipate and address possible counter arguments. Future research should address the saliency of different arguments to the public and key decision makers in government.
RECENT RESULTS FROM LATTICE CALCULATIONS
Authors: HASHIMOTO SHOJI
Published: October 2005

Recent results from lattice QCD calculations relevant to particle physics phenomenology are reviewed. They include the calculations of strong coupling constant, quark masses, kaon matrix elements, and D and B meson matrix elements. Special emphasis is on the recent progress in the simulations including dynamical quarks.
EXPERIMENTAL REVIEW OF NEW RESULTS ON HADRON SPECTROSCOPY
Authors: JIN SHAN
Published: October 2005

In this talk, I will review the most important progress in the field of hadron spectroscopy in recent one year, especially on multi-quark candidates, including pentaquarks, X(3872), D s (2632) and resonant structures near [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and ωJ/ψ mass thresholds. I will also review the new results on scalar mesons, including σ, κ, f 0(980), f 0(1370), f 0(1500) and possible f 0(1790). This talk will also cover some other interesting results from BES and CLEO-c experiments.
HADRON SPECTROSCOPY (THEORY): DIQUARKS, TETRAQUARKS, PENTAQUARKS AND NO QUARKS
Authors: CLOSE F. E.
Published: October 2005

States beyond those expected in the simple constituent quark model are now emerging. I focus on the scalar glueball and its mixing with states in the [Formula: see text] nonet, and also on correlations in Strong QCD that may form diquarks and seed [Formula: see text] states. Some models of the pentaquark candidate Θ(1540) are critically discussed.
PARTICLE ASTROPHYSICS AND COSMOLOGY
Authors: BINÉTRUY P.
Published: October 2005

Recent developments in particle astrophysics and cosmology are described, with an emphasis on new observations and their impacts on the way we formulate the main open questions in the field.
R&D FOR FUTURE DETECTORS
Authors: BRAU JAMES E.
Published: October 2005

Research and development of detector technology are critical to the future particle physics program. The goals of the International Linear Collider, in particular, require advances that are challenging, despite the progress driven in recent years by the needs of the Large Hadron Collider. The ILC detector goals and challenges are described and the program to address them is summarized.
LINEAR COLLIDER PHYSICS
Authors: MILLER DAVID J.
Published: October 2005

The International Linear Collider has a rich physics programme, whatever lies beyond the standard model. Accurate measurement of the top quark mass is needed to constrain the model or its extensions. If there is a light Higgs boson the LHC should see it, but the ILC will pin down its characteristics and test them against model predictions. If Supersymmetric particles appear the ILC will measure a complementary set of them to those seen at the LHC, and may allow extrapolation to the Grand Unified scale. And if a strong electroweak sector is indicated the ILC will be sensitive to the presence of new structures in difermion and diboson systems up to higher masses than the direct search range of the LHC. Beyond the LHC and ILC there could be need for a multi TeV lepton collider.
On absolute matrix summability methods
Authors: Özarslan H. S. , Öğdük H. N.
Published: October 2005

We have proved a theorem on summability methods.
This theorem includes a known theorem.
On a continuous majority rule
Authors: Kim Won Kyu , Lee Kyoung Hee
Published: October 2005

A seminal paper by May characterizes the majority rule in terms of
anonymity, neutrality, and positive responsiveness. Since
then, there have been many characterizations of the majority rule
using different axioms by several authors. In this paper, we will
introduce the concept of a continuous majority rule which
generalizes the previous social welfare functions beyond the
discrete values, and using new axioms, we will give a
characterization of the continuous majority rule.
Expansion of α‐open sets and decomposition of α‐continuous mappings
Authors: Rajamani M. , Bagyalakshmi K.
Published: October 2005

We introduce the notions of expansion 𝒜α of α‐open sets and 𝒜α‐expansion
α‐continuous mappings in topological spaces. The
main result of this paper is that a map f is α‐continuous
if and only if it is 𝒜α‐expansion
α‐continuous and ℬα‐expansion
α‐continuous, where 𝒜α, ℬα are two mutually dual expansions.
Matrix transformations and Walsh′s equiconvergence theorem
Authors: Selvaraj Chikkanna R. , Selvaraj Suguna
Published: October 2005

In 1977, Jacob defines Gα, for any 0 ≤ α < ∞, as the set of all complex sequences x such that . In this paper, we apply Gu − Gv matrix transformation on the sequences of operators given in the
famous Walsh′s equiconvergence theorem, where we have that the
difference of two sequences of operators converges to zero in a
disk. We show that the Gu − Gv matrix transformation of the
difference converges to zero in an arbitrarily large disk. Also,
we give examples of such matrices.
Metabolic Mapping of MCF10A Human Breast Cells via Multiphoton Fluorescence Lifetime Imaging of the Coenzyme NADH
Authors: Bird Damian K. , Yan Long , Vrotsos Kristin M. , Eliceiri Kevin W. , Vaughan Emily M. , Keely Patricia J. , White John G. , Ramanujam Nirmala
Published: October 2005

Biochemical estimation of NADH concentration is a useful method for monitoring cellular metabolism, because the NADH/NAD+ reduction-oxidation pair is crucial for electron transfer in the mitochondrial electron chain. In this article, we present a novel method for deriving functional maps of intracellular reduction-oxidation ratio in vivo via measurement of the fluorescence lifetimes and the ratio of free and protein-bound NADH using two-photon fluorescence lifetime imaging (FLIM). Through systematic analysis of FLIM data from the control cells, it was observed that there is a statistically significant decrease in the fluorescence lifetime of both free and protein-bound NADH and the contribution of protein-bound NADH as cells progress from an early to logarithmic to confluent phase. Potassium cyanide (KCN) treatment and serum starvation of cells yielded similar changes. There was a statistically significant decrease in the fluorescence lifetime of protein-bound and free NADH at the early and logarithmic phase of the growth curve and a statistically significant decrease in the contribution of protein-bound NADH relative to that observed in the control cells at all three phases of the growth curve. The imposed perturbations (confluence, serum starvation, and KCN treatment) are all expected to result in an increase in the ratio of NADH/NAD+. Our studies suggest that the fluorescence lifetime of both the free and the protein-bound components of NADH and the ratio of free to protein-bound NADH is related to changes in the NADH/NAD+ ratio.
Caspase-1α Is Down-regulated in Human Ovarian Cancer Cells and the Overexpression of Caspase-1α Induces Apoptosis
Authors: Feng Qiang , Li Peixiang , Salamanca Clara , Huntsman David , Leung Peter C.K. , Auersperg Nelly
Published: October 2005

Caspase-1 plays a key role in the processing of cytokines and in the apoptosis of neurons and macrophages. Whether it also causes apoptosis of cancer cells has been unclear. In this study, we screened an array of apoptosis-related proteins in ovarian carcinoma cell lines and their tissue of origin, ovarian surface epithelium (OSE). Caspase-1α protein was abundant in OSE and in nontumorigenic OSE with extended but limited life spans (immortalized OSE), but was reduced in the cancer lines A2780 and OVCAR10. By Western blot and immunofluorescence, caspase-1α levels were greatly reduced in six of eight ovarian carcinoma lines compared with OSE. By real-time reverse transcription-PCR, steady-state transcripts of the CASP1 gene were proportional to protein levels. Caspase-1α overexpression caused significant apoptosis, but overexpression of a caspase-1α mutant without catalytic activity did not, confirming that the effect was caspase-1α–specific. Immunofluorescence of caspase-1α and terminal nucleotidyl transferase–mediated dUTP-X nick end labeling colocalization clearly established a link between apoptosis and caspase-1α expression. Caspase-9 and caspase-3 were activated in caspase-1α overexpressing A2780 cells, suggesting involvement of an intrinsic apoptotic pathway. Caspase-1α overexpression did not change the apoptotic effect of cisplatin in A2780 and OVCAR10 cells, suggesting that this agent activates a different pathway. Immunohistochemically, caspase-1 was lower in ovarian serous carcinomas than in OSE. Our study indicates, for the first time, that caspase-1α is proapoptotic in ovarian cancer cells, and raises the possibility that its down-regulation is one of the mechanisms which increase resistance to apoptosis in cancer cells.
Suppression of Progression and Metastasis of Established Colon Tumors in Mice by Intravenous Delivery of Short Interfering RNA Targeting KITENIN, a Metastasis-Enhancing Protein
Authors: Lee Ji Hee , Cho Eun Song , Kim Mi-Young , Seo Young-Woo , Kho Dhong Hyo , Chung Ik Joo , Kook Hyun , Kim Nack Sung , Ahn Kyu Youn , Kim Kyung Keun
Published: October 2005

KITENIN promotes invasion of mouse colon adenocarcinoma (CT-26) cells in vivo. Here, we studied the effects of in vivo KITENIN ablation on established tumors by using pSUPER vectors (pSUPER-KITENIN) producing short interfering RNA (siRNA). When pSUPER-KITENIN was given weekly or semiweekly for 1 month into tail vein of syngeneic mice that have established colon tumors, tumor size regressed markedly and metastases were inhibited. In mice injected with pSUPER-KITENIN, serum interleukin-2 (IL-2) and IFN-γ increased and CD4+ and CD8+ T cells infiltrated in the regressed tumor tissues. These effects, observed beginning 2 days after i.v. injection, imply that immune response is involved in the antitumor action of pSUPER-KITENIN. Using a yeast two-hybrid assay, we identified two KITENIN-interacting proteins for the possible mediators of these actions: 90K protein, a known immune modulatory glycoprotein, and protein kinase C inhibitor (PKCI). 90K was increased in the culture medium from CT-26/antisense KITENIN/90K cells. Double culture of accessory cells with CT-26/antisense KITENIN/90K cells revealed increased secretion of IL-1 and IL-6. Overexpression of 90K in CT-26/antisense KITENIN cells further delayed tumor growth compared with that of CT-26/antisense KITENIN cells. Actin arrangement was distorted in CT-26/antisense KITENIN and CT-26/antisense PKCI cells, whereas overexpression of PKCI resulted in increased invasiveness to fibronectin. Thus, antitumor effects of KITENIN siRNA derives from both the generation of a tumor-specific immune response in vivo through increased 90K secretion from tumor cells and the suppression of tumor invasion in which PKCI is related to increased invasiveness. Moreover, siRNA targeting of KITENIN can function as a chemotherapeutic strategy against colon cancer.
Genomewide Single Nucleotide Polymorphism Microarray Mapping in Basal Cell Carcinomas Unveils Uniparental Disomy as a Key Somatic Event
Authors: Teh Muy-Teck , Blaydon Diana , Chaplin Tracy , Foot Nicola J. , Skoulakis Spyros , Raghavan Manoj , Harwood Catherine A. , Proby Charlotte M. , Philpott Michael P. , Young Bryan D. , Kelsell David P.
Published: October 2005

Basal cell carcinoma is the most common human cancer with increasing incidence reported worldwide. Despite the aberrant signaling role of the Hedgehog pathway, little is known about the genetic mechanisms underlying basal cell carcinomas. Towards a better understanding of global genetic events, we have employed the Affymetrix Mapping 10K single nucleotide polymorphism (SNP) microarray technique for “fingerprinting” genomewide allelic imbalance in 14 basal cell carcinoma–blood pair samples. This rapid high-resolution SNP genotyping technique has revealed a somatic recombination event–uniparental disomy, leading to a loss of heterozygosity (LOH), as a key alternative genetic mechanism to allelic imbalances in basal cell carcinomas. A highly conserved LOH region at 9q21-q31 was found in 13 of 14 (93%) basal cell carcinomas. Further statistical and fluorescence in situ hybridization analyses confirmed that the 9q LOH was a result of uniparental disomy in 5 of 13 (38%) basal cell carcinomas. De novo mutations in the Patched 1 gene (PTCH) were found in 9 of 13 (69%) basal cell carcinomas with 9q LOH. A second important locus, containing LOH at 6q23-q27 was found in 5 of 14 (36%) basal cell carcinomas, suggesting that the presence of an additional putative tumor suppressor gene may be contributing to basal cell carcinoma development. This study shows that the rate of 9q LOH in basal cell carcinomas has been previously underestimated. Furthermore, we provide the first evidence that uniparental disomy due to somatic recombination constitutes one of the mechanisms of LOH in basal cell carcinoma tumorigenesis.
Fusion Protein Vaccine by Domains of Bacterial Exotoxin Linked with a Tumor Antigen Generates Potent Immunologic Responses and Antitumor Effects
Authors: Liao Chao-Wei , Chen Chi-An , Lee Chien-Nan , Su Yi-Ning , Chang Ming-Cheng , Syu Ming-Houg , Hsieh Chang-Yao , Cheng Wen-Fang
Published: October 2005

Antigen-specific immunotherapy represents an attractive approach for cancer treatment because of the capacity to eradicate systemic tumors at multiple sites in the body while retaining the requisite specificity to discriminate between neoplastic and nonneoplastic cells. It has been shown that certain domains of bacterial exotoxins facilitate translocation from extracellular and vesicular compartments into the cytoplasm. This feature provides an opportunity to enhance class I and/or II presentation of exogenous antigen to T lymphocytes. We investigated previously whether the translocation domain (domain II) of Pseudomonas aeruginosa exotoxin A with a model tumor antigen, human papillomavirus type 16 E7, in the context of a DNA vaccine could enhance vaccine potency. We then attempted to determine whether this chimeric molecule could also generate strong antigen-specific immunologic responses and enhance the potency of cancer vaccine in the protein format. Our results show that vaccination with the PE(ΔIII)-E7-KDEL3 fusion protein enhances MHC class I and II presentation of E7, leading to dramatic increases in the number of E7-specific CD8+ and CD4+ T-cell precursors and markedly raised titers of E7-specific antibodies. Furthermore, the PE(ΔIII)-E7-KDEL3 protein generates potent antitumor effects against s.c. E7-expressing tumors and preestablished E7-expressing metastatic lung tumors. Further, mice immunized with PE(ΔIII)-E7-KDEL3 protein vaccine also retained long-term immunologic responses and antitumor effects. Our results indicate that retrograde-fusion protein via the delivery domains of exotoxins with an antigen greatly enhances in vivo antigen-specific immunologic responses and represents a novel strategy to improve cancer vaccine potency.
Activator Protein 2α Status Determines the Chemosensitivity of Cancer Cells: Implications in Cancer Chemotherapy
Authors: Wajapeyee Narendra , Raut Chandrashekhar Ganpat , Somasundaram Kumaravel
Published: October 2005

Cancer chemotherapeutic drugs induce apoptosis by several pathways. Inactivation of proapoptotic genes, or activation of survival signaling, leads to chemoresistance. Activator protein 2α (AP-2α), a developmentally regulated sequence-specific DNA-binding transcription factor, has been shown to function like a tumor suppressor. Here, we show that controlled expression of AP-2α, using tetracycline-inducible system, increased the chemosensitivity of cancer cells by severalfold by sensitizing cells to undergo apoptosis upon chemotherapy. Under these conditions, neither AP-2α expression nor drug treatment resulted in apoptosis induction, whereas in combination the cancer cells underwent massive apoptosis. We found that endogenous AP-2α protein is induced posttranscriptionally by various chemotherapeutic drugs. Blocking the endogenous AP-2α by small interfering RNA in human cancer cells lead to decreased apoptosis, increased colony formation, and chemoresistance irrespective of their p53 status upon chemotherapy. We further show that 5-aza-2′-deoxycytidine induced reexpression of AP-2α in MDA-MB-231 breast cancer cells (wherein AP-2α expression is silenced by hypermethylation), resulted in massive apoptosis induction, increased chemosensitivity, decreased colony formation, and loss of tumorigenesis upon chemotherapy. However, in MDA-MB-231 cells transfected with AP-2α small interfering RNA, 5-aza-2′-deoxycytidine treatment failed to increase apoptosis and chemosensitivity. The treatment also resulted in increased colony formation and efficient tumor formation upon chemotherapy. These results establish an important role for AP-2α in cancer cell chemosensitivity and provide new insights for modifying the chemosensitivity of cancer cells by activating apoptotic pathways.
Destruction Box–Dependent Degradation of Aurora B Is Mediated by the Anaphase-Promoting Complex/Cyclosome and Cdh1
Authors: Stewart Scott , Fang Guowei
Published: October 2005

Aurora B kinase, a subunit of the chromosomal passenger protein complex, plays essential roles in spindle assembly, chromosome bi-orientation, and cytokinesis. The kinase activity of Aurora B, which peaks in mitosis, is tightly controlled in the cell cycle. Modulation of Aurora B protein levels could partly account for the regulation of its kinase activity in the cell cycle. However, little is known on the molecular mechanism of regulation of Aurora B levels. Here, we examined Aurora B protein levels and confirmed that they fluctuate during the cell cycle, peaking in mitosis and dropping drastically in G1. This profile for Aurora B in the cell cycle is reminiscent of those for substrates of the anaphase-promoting complex/cyclosome (APC/C), a ubiquitin ligase essential for mitotic progression. Indeed, Aurora B is a substrate of APC/C both in vitro and in vivo. Aurora B is efficiently ubiquitinated in an in vitro reconstituted system by APC/C that had been activated by Cdh1. The recognition of Aurora B by APC/C-Cdh1 is specific as it requires the presence of a conserved D-box at the COOH terminus of Aurora B. Furthermore, endogenous Aurora B and Cdh1 form a complex exclusively in mitotic cells. Degradation of Aurora B at the end of mitosis requires Cdh1 in vivo as a reduction of the Cdh1 level by RNA interference stabilizes the Aurora B protein. We conclude that, as a key mitotic regulator, Aurora B is regulated both by its activation during early mitosis and by its destruction by APC/C-Cdh1 in late mitosis and in G1.
Atm Heterozygosity Cooperates with Loss of Brca1 to Increase the Severity of Mammary Gland Cancer and Reduce Ductal Branching
Authors: Bowen T.J. , Yakushiji Hiroyuki , Montagna Cristina , Jain Sonia , Ried Thomas , Wynshaw-Boris Anthony
Published: October 2005

The role of homozygous ataxia telangiectasia mutated (ATM) mutations in familial and sporadic forms of cancer is well established, but the contribution of ATM heterozygosity to mammary gland and other cancers has been controversial. To test the effect of Atm heterozygosity on mammary gland cancer, mice with complete loss of exon 11 of Brca1 specifically in mammary epithelium (Brca1-MG-Δex11) were studied in either Atm heterozygous or Atm wild-type backgrounds. Targeted deletion of Brca1 in mammary epithelium resulted in carcinomas and adenocarcinomas of varying histology with long (>9 months) latency. Latency to tumorigenesis was found to be unchanged in the Brca1-MG-Δex11;Atm heterozygous mice compared with Brca1-MG-Δex11;Atm wild-type mice. However, the mice displayed variable tumor severity and differences in mammary tissue development. Mammary tumors from Brca1-MG-Δex11;Atm heterozygous mice were anaplastic and undifferentiated in all 20 tumors tested, whereas tumors from mice that were Brca1-MG-Δex11 but wild-type for Atm displayed variable histologic profiles, with some anaplastic tumors and other differentiated and less invasive tumor types. Previously reported developmental defects for Brca1-deficient mice were also observed in our model with and without Atm heterozygosity, but Brca1-MG-Δex11;Atm heterozygous mice displayed decreased ductal branching during puberty, a phenotype that was not observed in Brca1-MG-Δex11;Atm wild-type mice. Our results provide evidence that Atm heterozygosity influences severity of mammary gland tumors in the Brca1-MG-Δex11 tumor-prone mouse and suggest that this mutation leads to a newly characterized developmental defect during glandular maturation.
Expression of the EWS/FLI-1 Oncogene in Murine Primary Bone-Derived Cells Results in EWS/FLI-1–Dependent, Ewing Sarcoma–Like Tumors
Authors: Castillero-Trejo Yeny , Eliazer Susan , Xiang Lilin , Richardson James A. , Ilaria Robert L.
Published: October 2005

Ewing sarcoma is the second most common malignant pediatric bone tumor. Over 80% of Ewing sarcoma contain the oncogene EWS/FLI-1, which encodes the EWS/FLI-1 oncoprotein, a hybrid transcription factor comprised of NH2-terminal sequences from the RNA-binding protein EWS and the DNA-binding and COOH-terminal regions of the Ets transcription factor FLI-1. Although numerous genes are dysregulated by EWS/FLI-1, advances in Ewing sarcoma cancer biology have been hindered by the lack of an animal model because of EWS/FLI-1–mediated cytotoxicity. In this study, we have developed conditions for the isolation and propagation of murine primary bone-derived cells (mPBDC) that stably express EWS/FLI-1. Early-passage EWS/FLI-1 mPBDCs were immortalized in culture but inefficient at tumor induction, whereas later-passage cells formed sarcomatous tumors in immunocompetent syngeneic mice. Murine EWS/FLI-1 tumors contained morphologically primitive cells that lacked definitive lineage markers. Molecular characterization of murine EWS/FLI-1 tumors revealed that some but not all had acquired a novel, clonal in-frame p53 mutation associated with a constitutive loss of p21 expression. Despite indications that secondary events facilitated EWS/FLI-1 mPBDC tumorigenesis, cells remained highly dependent on EWS/FLI-1 for efficient transformation in clonogenic assays. This Ewing sarcoma animal model will be a useful tool for dissecting the molecular pathogenesis of Ewing sarcoma and provides rationale for the broader use of organ-specific progenitor cell populations for the study of human sarcoma.