bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic measurements of surface gravity wave spectra in Monterey Bay using mode travel-time fluctuations
Authors: Miller James H. , Lynch James F. , Chiu Ching-Sang , Westreich Eric L. , Gerber James S. , Hippenstiel Ralph , Chaulk Edwin
Published: October 2005

Earlier work by Miller et al. [J. Acoust. Soc. Am. 86, 326–345 (1989)] suggested that the surface gravity wave frequency-direction spectrum could be measured using acoustic tomography signals. An experiment was performed in Monterey Bay, California, from 12–16 December 1988 to validate this earlier work. During that period, an acoustic tomography source with a center frequency of 224 Hz and bandwidth of 16 Hz was deployed, continuously repeating its coded transmissions every 1.9375 s. The transmissions were received on a number of modified sonobuoys placed on the continental shelf at a range of approximately 55 km. Although the acoustic propagation was complicated by the presence of the Monterey Submarine Canyon, a hybrid ray and mode interpretation explains the observations. The main effect of the surface waves on the acoustic signals is determined to occur in the shallow continental shelf portion of the path. On the shelf, it is shown that the resolved acoustic normal modes exhibit the fluctuations in travel time described in our earlier work. The acoustic measurements of the surface wave spectrum compared well with measurements made by a pitch-roll wave buoy maintained in the area by the National Data Buoy Center (NDBC). The acoustic and buoy spectra agreed well on the location of the peak swell frequency; the root-mean-square (rms) wave amplitudes from the two measures agreed to within 7%.
A model of auditory pattern analysis based on component-relative-entropy
Authors: Lutfi Robert A.
Published: October 2005

Recently results from detection and information theory have been used to predict performance of human observers in experiments involving the discriminability of changes in individual components of unfamiliar or uncertain tone patterns [R. A. Lutfi, J. Acoust. Soc. Am. 91, 3391–3401 (1992)]. In this paper, the theoretical analysis is expanded to yield a general rule of pattern analysis that accounts for nearly all of the major results of such experiments conducted over the last 18 years. The rule can be stated as follows: Component discriminability in an unfamiliar tone pattern (profile or sequence) is a linearly increasing function of the component’s relative entropy (CoRE) in the pattern. Ancillary: The threshold for detection of a change decreases by one order of magnitude (factor of 10) for each one bit increase in CoRE. This precise relation of threshold to CoRE is demonstrated repeatedly in a review of past studies, and is shown to account for the relative effects of a variety of important variables and their interactions. Such variables include the total duration of the pattern; the number of tones in the pattern; the number of tones subject to change; the relative level and duration of individual tones in the pattern; the relative variability and the physical dimension of the tones’ parameters that are subject to change; the number and position of targets in the pattern; the psychophysical procedure used (method of adjustment versus same-different), the type of discrimination task (frequency versus intensity discrimination), and the manner of presentation of the tones (simultaneous or sequential). The CoRE rule seems to reflect a general property of auditory analysis wherein the perception of patterns in an ensemble is dominated by those features that dominate the variance of the ensemble.
Detection and identification of a single modulated carrier in a complex sound
Authors: Moore Brian C. J. , Bacon Sid P.
Published: October 2005

Hall and Grose [J. Acoust. Soc. Am. 90, 3028–3035 (1991)] reported that subjects had difficulty in deciding which carrier in a two-carrier complex sound was modulated. The present experiments examined how the ability to identify a single modulated carrier was affected by the number of carriers in the complex and by harmonicity. Initially, thresholds were measured for detecting amplitude modulation of a single carrier in a complex sound. Thresholds were higher when that carrier was one of the inner carriers in a six-carrier harmonic or inharmonic complex than when it formed part of a two-carrier complex. Thresholds were only slightly, if at all, higher when the modulated carrier was varied randomly from trial to trial than when its frequency was fixed within a block of trials. Next, subjects were required to decide whether the frequency of a single modulated carrier (with a suprathreshold modulation depth) in a complex sound was the same as or different from the frequency of a probe composed of a single modulated carrier. They generally performed well above chance. Performance was not greatly affected by whether the probe was presented before or after the complex, but was generally slightly better for a modulation depth of 100% than for a depth of 50%. Randomly varying the level of each carrier in the complexes from one stimulus to the next produced only a slight impairment of performance, indicating that short-term across-frequency differences in level were not used to identify the modulated carrier in experiment 2. Overall, performance was best for the six-carrier harmonic complex, less good for the six-carrier inharmonic complex, and worst for the two-carrier complex. The results are interpreted in terms of perceptual grouping.
A model to predict the ultrasonic echo responses of small targets in solids
Authors: Weight John P.
Published: October 2005

A novel model is developed to predict the echo response of a small target at arbitrary position in the field of a circular transducer directly coupled to a solid. The waves incident on the target are calculated using an earlier model, which describes the field radiated into solids in terms of plane and edge waves and allows for the existence of both compression and shear waves. The new model treats the target as a point-like radiator with motion given by the normal component of the incident particle velocity. An expression for the overall echo impulse response is developed by invoking the principle of reciprocity, assuming a single transducer is used as both emitter and receiver. Simplifications inherent in the model keep computational times very short but allow predictions to be made with an accuracy adequate to show all of the major features of the responses. Comparisons of the predictions of the model with experimental measurements of echo responses from 2-mm-diam round-bottomed holes in steel show good agreement. The complicated multipulse structure of the echo response from even a point-like target is explained in terms of the scattering, mode conversion, and reception of plane and edgewaves. The implications of the results for quantitative nondestructive evaluation using ultrasound are discussed.
Source localization in an uncertain acoustic scattering environment
Authors: Haralabus G. , Premus V. , Alexandrou D. , Nolte L. W. , Richardson A. M.
Published: October 2005

The sensitivity of conventional matched-field processing algorithms to uncertainty in ocean acoustic environmental parameters has prompted the design of more robust methods for source localization. In a recent study, Richardson and Nolte [J. Acoust. Soc. Am. 89, 2280–2284 (1991)] reported on the development of a new algorithm which incorporates prior knowledge of the environmental uncertainty into the design of the matched-field processing algorithm. The result was the optimum uncertain field processor (OUFP). The present study addresses the problem of source localization in an imperfectly known acoustic scattering environment. The propagation scenario of interest, the surface duct, is characterized by the property that the received pressure field consists primarily of rays which are scattered from the sea surface. The surface roughness statistics are presumed to be axisymmetric, parametrized by rms height and correlation length. Two approaches to modeling the scattered field will be considered (1) the Eckart reflection coefficient and (2) numerical evaluation of the Helmholtz–Kirchhoff integral for the quadrature components in the specular direction. In each case, simulation results demonstrate that the OUFP outperforms a conventional matched-field processor when surface statistics are imperfectly known. It is also noted that, in the context of source localization, the Eckart method is only suitable for modeling scatter from slightly rough surfaces. For rougher surfaces, it is seen that combining the Kirchhoff model with the OUFP algorithm results in robust localization performance for a propagation channel that is dominated by acoustic interaction with a nondeterministic boundary.
Ultrasonic fields of a convex semispherical transducer
Authors: Gibson William G. R. , Cobbold Richard S. C. , Foster F. Stuart
Published: October 2005

A simple theoretical model is developed to predict the transmit pressure field of a convex semispherical transducer and the results are verified experimentally. The impulse velocity potential and the velocity/voltage response are calculated, and from these the pressure response for a given excitation waveform are obtained. A polyvinylidene fluoride (PVDF) transducer was constructed with a radiation angle of 60° and a radius of 6.35 mm, operating at 8 MHz. Measured pressure fields compared well with those predicted by the model. The acoustic intensity across the full width, half-maximum angle of 60° when using a six-cycle burst of 8 MHz, had a maximum variation of 3 dB.
Ocean surface processes affecting high-frequency acoustics
Authors: Melville W. Kendall
Published: October 2005

Ocean surface processes affecting high-frequency acoustics are reviewed. The generation, propagation, and attenuation of high-frequency sound at and near the ocean surface is of interest for many current problems in acoustics and its applications in oceanography. While models of surface scattering by short surface gravity waves and even shorter gravity-capillary waves can be formulated, the scatterers are not homogeneously distributed on the surface. Nonlinear interactions with longer waves and swell, and direct forcing by the wind lead to modulations of the scatterers that are poorly understood. Nonlinear effects may not be weak, with the surface slope becoming infinite in breaking waves. Breaking waves also generate sound as the entrained air breaks up into smaller bubbles that radiate as they relax towards their equilibrium shape. The bubble plumes and clouds scatter and attenuate sound but field measurements of the acoustic properties of the bubble layer near the surface vary significantly. Bubble clouds may align with coherent Langmuir circulations. The surface layers may also be regions of strong temperature gradients (with concomitant sound-speed gradients), which are broken up by thermal convection and breaking waves. Natural and man-made surface slicks can suppress the waves and thereby modify both active and passive acoustics. These and other upper ocean processes will be reviewed.
The preliminary application of Gabor spectrogram analysis in speech samples
Authors: Jiang Jack J. , Qian Shie , Hanson David G. , Cuasay Eric , Logemann Jerilyn
Published: October 2005

It has been widely recognized that the FFT-based spectrogram does not provide good simultaneous resolution in both time and frequency domains. A new method of spectral analysis has been developed based upon the Gabor expansion and the Wigner–Ville distribution. The resolution of the Gabor spectrogram is twice as high as that of a FFT-based spectrogram. In this report, FFT-based spectrograms and Gabor spectrograms are compared for 5 English vowels, 6 stops consonants, 4 fricatives, and vowels format transitions in a CVD contents on 6 normal subjects. Results demonstrate that the Gabor spectrogram is a promising alternative for FFT-based spectrogram in speech analysis because of its higher temporal and frequency resolution.
Effect of microphone placement on adaptive noise cancellation methods with machine ball bearing measurements to detect bearing flaws in reverberant environments
Authors: Carney Matthew S. , Mann J. Adin
Published: October 2005

Sound measurements on operating machinery in reverberant environments are difficult to analyze. Adaptive noise algorithms [C. C. Tan, IECON, 703–708 (1985)] are available to reduce the amount of background noise in the measured data. Due to the reverberation of the environment, proper placement of the microphones is important to achieve the greatest noise cancellation from the algorithm. Measurements were taken on bearings with known flaws under different loads and speeds. Results of these measurements will show the effectiveness of sound pressure measurements, and sound intensity measurements, to detect bearing flaws with the help of the adaptive noise cancellation algorithm when the microphones are properly placed.
Three-dimensional modeling of low-frequency active source arrays
Authors: Cox Donald L. , Chapman Robert T.
Published: October 2005

A three-dimensional analysis of two closely spaced class IV flextensional transducers is presented. The analysis was performed using a finite-element program, nomad, developed to solve extremely large three-dimensional problems. The program nomad (NO Matrix Decomposition) uses the conjugate gradient iterative solution technique with element by element (EBE) storage and preconditioning and enhanced Cray vector processing. In order to demonstrate the modeling capabilities of the code, no symmetry downsizing of the two transducer model was invoked. Stress and flux density information are provided for the transducer response. For the acoustic media, both pressure and intensity information is presented. [Work supported by the NUWC IR/IED program.]
Observations of acoustic scattering associated with ocean microstructure in the Arctic
Authors: Plueddemann Albert J. , Padman Laurie , Stanton Timothy P. , Sherman Jeffrey T. , Pinkel Robert
Published: October 2005

Observations from an Arctic ice camp on the Northwest flank of the Yermak Plateau indicate that under some conditions ocean microstructure may be detectable with ‘‘standard’’ acoustic instrumentation (i.e., acoustic Doppler current profilers) of moderately high frequency (150–300 kHz). The data set, collected during the Cooperative Eastern Arctic Experiment (CEAREX), includes simultaneous observations of kinetic energy dissipation rate, temperature dissipation rate, and acoustic backscatter from both 160- and 300-kHz Doppler profilers. The turbulence levels observed during CEAREX were particularly strong (ε≳10−7 W kg−1) and occurred in well-defined patches. Patches in the mixed layer were not associated with backscattered intensity anomalies. However, intensity anomalies of 2 to 6 dB were found to be coincident in time and space with the patches of strong turbulence in the thermocline. The acoustic intensity anomalies were intermittent, presumably because they were detectable only above a threshold that represented the background particulate scattering level. Theoretical predictions of the acoustic intensity level based on the microstructure measurements are used to support the hypothesis that the enhanced scattering levels are due to temperature microstructure rather than variations in particulate scattering.
Analysis of rough voice from a nonlinear dynamics point of view
Authors: Berry David A. , Titze Ingo R. , Herzel Hanspeter
Published: October 2005

Because the vocal folds are nonlinear systems with many degrees of freedom, bifurcations and chaos should be expected for certain parameter configurations. Indeed, bifurcations and chaos appear in some of the simplest models of vocal fold vibration. They are also seen in more complex models, in models that incorporate left–right asymmetries, and in biomechanical simulations of vocal fold oscillations. Furthermore, an acoustical analysis of many types of rough voice (e.g., creaky voice, vocal fry, and newborn infant cries) reveals an intimate relationship between voice mechanics and bifurcations and chaos. Likely physiological mechanisms of the observed nonlinear phenomena are presented. Basic concepts and analysis techniques from nonlinear dynamics are reviewed and compared with traditional voice analysis schemes. Finally, it is shown how much of the terminology in the literature describing rough voice can be unified within the framework of nonlinear dynamics. [This research was supported by Grant. No. P60 DC00976 from the National Institute on Deafness and Other Communication Disorders.]
Experimental evaluation of the accuracy of the Sabine and Eyring theories in the case of non-low surface absorption
Authors: Hodgson Murray
Published: October 2005

The Sabine and Eyring diffuse-field theories are often used to predict the sound decay/reverberation time and steady-state sound-pressure levels in rooms. The Sabine theory can be considered to be an approximate version, valid for low surface absorption, of the Eyring theory, in principle valid for any surface absorption values. However, some practitioners believe that the Sabine theory is accurate for any absorption value. Further, there is some debate as to whether or not a 1−α factor should be included in the reverberant sound-pressure term of these theories. Experiments were done, in a 1:2.5 scale model reverberation room with surfaces of varying absorption. The results were compared with predictions by various versions of the Sabine and Eyring theories in order to evaluate their accuracies in the case of non-low surface absorption. It is concluded that the 1−α factor must be included to obtain accuracy. Eyring, but not Sabine, predictions were found to agree well with experiment, suggesting that only the Eyring theory can be accurate in the case of non-low absorption.
Identification and Functional Characterization of Brainstem Cannabinoid CB2Receptors
Authors: Van Sickle Marja D. , Duncan Marnie , Kingsley Philip J. , Mouihate Abdeslam , Urbani Paolo , Mackie Ken , Stella Nephi , Makriyannis Alexandros , Piomelli Daniele , Davison Joseph S. , Marnett Lawrence J. , Di Marzo Vincenzo , Pittman Quentin J. , Patel Kamala D. , Sharkey Keith A.
Published: October 2005

The presence and function of CB2receptors in central nervous system (CNS) neurons are controversial. We report the expression of CB2receptor messenger RNA and protein localization on brainstem neurons. These functional CB2receptors in the brainstem were activated by a CB2receptor agonist, 2-arachidonoylglycerol, and by elevated endogenous levels of endocannabinoids, which also act at CB1receptors. CB2receptors represent an alternative site of action of endocannabinoids that opens the possibility of nonpsychotropic therapeutic interventions using enhanced endocannabinoid levels in localized brain areas.
ON ONE-MEMBRANE P SYSTEMS OPERATING IN SEQUENTIAL MODE
Authors: DANG ZHE , IBARRA OSCAR H.
Published: October 2005

In the standard definition of a P system, a computation step consists of a parallel application of a "maximal" set of nondeterministically chosen rules. Referring to this system as a parallel P system, we consider in this paper a sequential P system, in which each step consists of an application of a single nondeterministically chosen rule. We show the following:

1. For 1-membrane purely catalytic systems (pure CS's), the sequential version is strictly weaker than the parallel version in that the former defines (i.e., generates) exactly the semilinear sets, whereas the latter is known to define nonrecursive sets.

2. For 1-membrane communicating P systems (CPS's), the sequential version can only define a proper subclass of the semilinear sets, whereas the parallel version is known to define nonrecursive sets.

3. Adding a new type of rule of the form: ab → axbyccomedcometo the CPS (a natural generalization of the rule ab → axbyccomein the original model), where x, y ∈ {here, out}, to the sequential 1-membrane CPS makes it equivalent to a vector addition system.

4. Sequential 1-membrane symport/antiport systems (SA's) are equivalent to vector addition systems, contrasting the known result that the parallel versions can define nonrecursive sets.

5. Sequential 1-membrane SA's whose rules have radius 1, (1,1), (1,2) (i.e., of the form (a, out), (a, in), (a, out; b, in), (a, out; bc, in)) generate exactly the semilinear sets. However, if the rules have radius 1, (1,1), (2,1) (i.e., of the form (ab, out; c, in)), the SA's can only generate a proper subclass of the semilinear sets.
DESCRIPTIONAL COMPLEXITY OF NFA OF DIFFERENT AMBIGUITY
Authors: LEUNG HING
Published: October 2005

In this paper, we study the tradeoffs in descriptional complexity of NFA (nondeterministic finite automata) of various amounts of ambiguity. We say that two classes of NFA are separated if one class can be exponentially more succinct in descriptional sizes than the other. New results are given for separating DFA (deterministic finite automata) from UFA (unambiguous finite automata), UFA from MDFA (DFA with multiple initial states) and UFA from FNA (finitely ambiguous NFA). We present a family of regular languages that we conjecture to be a good candidate for separating FNA from LNA (linearly ambiguous NFA).
A CHARACTERIZATION OF THE ARITHMETICAL HIERARCHY BY LANGUAGE EQUATIONS
Authors: OKHOTIN ALEXANDER
Published: October 2005

Language equations with all Boolean operations and concatenation and a particular order on the set of solutions are proved to be equal in expressive power to the first-order Peano arithmetic. In particular, it is shown that the class of sets representable using k variables (for every k ≥ 2) is exactly the k-th level of the arithmetical hierarchy, i.e., the sets definable by recursive predicates with k alternating quantifiers. The property of having an extremal solution is shown to be nonrepresentable in first-order arithmetic.
MINIMALIZATIONS OF NFA USING THE UNIVERSAL AUTOMATON
Authors: POLÁK LIBOR
Published: October 2005

As is well known, each minimal NFA for a regular language L is isomorphic to a subautomaton of the so-called universal automaton [Formula: see text] for L. We explore and compare various conditions on sets of states of [Formula: see text] which are related to the fact that induced subautomata of [Formula: see text] accept the whole language L. The methods of several previous works on minimalizations of NFA can be modified so that they fit in our approach. We also propose a new algorithm which is easy to implement.
MAGIC NUMBERS FOR SYMMETRIC DIFFERENCE NFAS
Authors: VAN ZIJL LYNETTE
Published: October 2005

Iwama et al. showed that there exists an n-state binary nondeterministic finite automaton such that its equivalent minimal deterministic finite automaton has exactly 2n - α states, for all n ≥ 7 and 5 ≤ α ≤ 2n-2, subject to certain coprimality conditions. We investigate the same question for both unary and binary symmetric difference nondeterministic finite automata. In the binary case, we show that for any n ≥ 4, there is an n-state symmetric difference nondeterministic finite automaton for which the equivalent minimal deterministic finite automaton has 2n - 1 + 2k - 1 - 1 states, for 2 < k ≤ n - 1. In the unary case, we consider a large practical subclass of unary symmetric difference nondeterministic finite automata: for all n ≥ 2, we argue that there are many values of α such that there is no n-state unary symmetric difference nondeterministic finite automaton with an equivalent minimal deterministic finite automaton with 2n - α states, where 0 < α < 2n - 1. For each n ≥ 2, we quantify such values of α precisely.
BOND-FREE LANGUAGES: FORMALIZATIONS, MAXIMALITY AND CONSTRUCTION METHODS
Authors: KARI LILA , KONSTANTINIDIS STAVROS , SOSÍK PETR
Published: October 2005

The problem of negative design of DNA languages is addressed, that is, properties and construction methods of large sets of words that prevent undesired bonds when used in DNA computations. We recall a few existing formalizations of the problem and then define the property of sim-bond-freedom, where sim is a similarity relation between words. We show that this property is decidable for context-free languages and polynomial-time decidable for regular languages. The maximality of this property also turns out to be decidable for regular languages and polynomial-time decidable for an important case of the Hamming similarity. Then we consider various construction methods for Hamming bond-free languages, including the recently introduced method of templates, and obtain a complete structural characterization of all maximal Hamming bond-free languages. This result is applicable to the θ-k-code property introduced by Jonoska and Mahalingam.
KV-COHOMOLOGY OF KOSZUL–VINBERG ALGEBROIDS AND POISSON MANIFOLDS
Authors: BOYOM MICHEL NGUIFFO
Published: October 2005

The main concern of this paper is the study of the relationships between the KV-cohomology of Koszul–Vinberg algebras and some properties of various geometrical objects. In particular we show how the scalar KV-cohomology of real or holomorphic Koszul–Vinberg algebroids is closely related to real or holomorphic Poisson manifolds. In the appendix we point out strong relationships between the pioneer work of Nijenhuis [42] and the KV-cohomology.
PROTON CONDUCTIVITY AND THERMODYNAMIC FEATURES IN THE HYDROGEN-BONDED MOLECULAR SYSTEMS
Authors: PANG XIAO-FENG , ZHANG HUAI-WU , ZN JUN
Published: October 2005

The proton conductivity and thermodynamic features, arising from motions of the ionic and bonded defects, in hydrogen-bonded molecular systems have been investigated by the quantum-mechanical method and the transfer integral way in our model, in which the collective effect and the mutual correlation between the protonic and heavy ionic sublattices are specially considered. We first derived the equations of motion and its soliton solutions from the model Hamiltonian. The results obtained show that this model can simultaneously support motions of the ionic and bonded defects which are due to competition of the double-well potential and non-linearly coupled interaction between the protons and heavy ions. Thus we find out the mobility of the kink-antikink pair and electrical-conductivity of the proton transfer in the hydrogen-bonded systems exposed in an externally applied electrical-field through the dynamic equation of the kink-antikink pair and its solution in this model. For ice, the mobility and electrical conductivity of the proton transfer obtained are about (6.5 - 6.9)×10-6 m 2/ V · s and (7.6 - 8.1)×10-3(Ω · m )-1, respectively, which are in the domain of semiconductors and are basically consistent with experimental values for the crystal. Finally we calculate the free energy and specific heat of the systems with finite temperature by the model Hamiltonian and transfer integral way. The specific heat is also consistent with experimental data. This is a very interesting result.
IT'S SO CLEAR: HYFLUX AND THE SUCCESS STORY OF A SINGAPORE FEMALE ENTREPRENEUR
Authors: LIM GHEE SOON
Published: October 2005

The present case documents the success story of water treatment specialist Hyflux, a young and growing technology company based in Singapore. Founded by female entrepreneur Olivia Lum in June 1989 on a shoestring budget of S$20,000 (US$1 = about S$1.70), Hyflux gradually and painstakingly built its clientele from scratch over a period of more than a decade. On January 17, 2001, Hyflux was listed on Singapore's SESDAQ, the country's stock market for smaller firms. Within three years after the listing, Hyflux chalked up impressive growth results: Revenues quadrupled from the prelisting level of S$20.8 million in 2000 to S$81 million in 2003; profit before tax shot up by more than 100%, from S$8.6 million in 2000 to S$20 million in 2003; and profit attributable to shareholders grew from S$6.4 million in 2000 to S$12.3 million in 2003. These results were accompanied by the firm's upgrading its listing to the Singapore Exchange main board on April 14, 2003. What factors have contributed to Hyflux's success? What is Hyflux's strategic competency and to what extent is the competency inimitable? How fast and in what ways is the competitive landscape changing? Does Hyflux need a strategic reorientation? These are some of the critical questions that a successful company should consider preemptively before the market or the competitive landscape turns against it. Students will gain a great deal of insight from this case of a successful female entrepreneur from Singapore.
Actin-dependent regulation of the cardiac Na+/Ca2+ exchanger
Authors: Condrescu Madalina , Reeves John P.
Published: October 2005

In the present study, the bovine cardiac Na+/Ca2+ exchanger (NCX1.1) was expressed in Chinese hamster ovary cells. The surface distribution of the exchanger protein, externally tagged with the hemagglutinin (HA) epitope, was associated with underlying actin filaments in regions of cell-to-cell contact and also along stress fibers. After we treated cells with cytochalasin D, NCX1.1 protein colocalized with patches of fragmented filamentous actin (F-actin). In contrast, an HA-tagged deletion mutant of NCX1.1 that was missing much of the exchanger's central hydrophilic domain Δ(241–680) did not associate with F-actin. In cells expressing the wild-type exchanger, cytochalasin D inhibited allosteric Ca2+ activation of NCX activity as shown by prolongation of the lag phase of low Ca2+ uptake after initiation of the reverse (i.e., Ca2+ influx) mode of NCX activity. Other agents that perturbed F-actin structure (methyl-β-cyclodextrin, latrunculin B, and jasplakinolide) also increased the duration of the lag phase. In contrast, when reverse-mode activity was initiated after allosteric Ca2+ activation, both cytochalasin D and methyl-β-cyclodextrin (Me-β-CD) stimulated NCX activity by ∼70%. The activity of the Δ(241–680) mutant, which does not require allosteric Ca2+ activation, was also stimulated by cytochalasin D and Me-β-CD. The increased activity after these treatments appeared to reflect an increased amount of exchanger protein at the cell surface. We conclude that wild-type NCX1.1 associates with the F-actin cytoskeleton, probably through interactions involving the exchanger's central hydrophilic domain, and that this association interferes with allosteric Ca2+ activation.
Osteoblast Ca2+ permeability and voltage-sensitive Ca2+ channel expression is temporally regulated by 1,25-dihydroxyvitamin D3
Authors: Bergh Joel J. , Shao Ying , Puente Erwin , Duncan Randall L. , Farach-Carson Mary C.
Published: October 2005

The cardiac subtype of the L-type voltage-sensitive Ca2+ channel (VSCC) Cav1.2 (α1C) is the primary voltage-sensitive channel responsible for Ca2+ influx into actively proliferating osteoblasts. This channel also serves as the major transducer of Ca2+ signals in growth-phase osteoblasts in response to hormone treatment. In this study, we have demonstrated that 24-h treatment of MC3T3-E1 preosteoblasts with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], a coupling factor for bone resorption, coordinately downregulates Cav1.2 (α1C) and uniquely upregulates T-type channel Cav3.2 (α1H). No other voltage-sensitive channel α-subunit of the 10 that were surveyed was upregulated by 1,25(OH)2D3. The shift from predominantly L-type to T-type channel expression has been demonstrated to occur at both mRNA and protein levels detected using quantitative PCR and immunohistochemistry with antibodies specific for each channel type. Functional and pharmacological studies using specific inhibitors have revealed that treatment with 1,25(OH)2D3 also alters the Ca2+ permeability properties of the osteoblast membrane from a state of primarily L-current sensitivity to T-current sensitivity. We conclude that the L-type channel is likely to support proliferation of osteoblast cells, whereas T-type channels are more likely to be involved in supporting differentiated functions after 1,25(OH)2D3-mediated reversal of remodeling has occurred. This latter observation is consistent with the unique expression of the T-type VSCC Cav3.2 (α1H) in terminally differentiated osteocytes as we recently reported.
Impaired hemorrhage tolerance in the obese Zucker rat model of metabolic syndrome
Authors: Frisbee Jefferson C.
Published: October 2005

As obese Zucker rats (OZR) manifesting the metabolic syndrome exhibit enhanced vascular adrenergic constriction and potentially an enhanced adrenergic activity vs. lean Zucker rats (LZR), this study tested the hypothesis that OZR exhibit an improved tolerance to progressive hemorrhage. Preliminary experiments indicated that, corrected for body mass, total blood volume was reduced in OZR vs. LZR. Anesthetized LZR and OZR had a cremaster muscle prepared for in situ videomicroscopy and had renal, splanchnic, hindlimb, and skeletal muscle perfusion monitored with flow probes. Arterial pressure, arteriolar reactivity to norepinephrine, and tissue/organ perfusion were monitored after either infusion of phentolamine or successive withdrawals of 10% total blood volume. Phentolamine infusion indicated that regional adrenergic tone under control conditions differs substantially between LZR and OZR, whereas with hemorrhage OZR exhibit decompensation in arterial pressure before LZR. Renal, distal hindlimb, and skeletal muscle perfusion decreased more rapidly and to a greater extent in OZR vs. LZR after hemorrhage. In contrast, hemorrhage-induced reductions in splanchnic perfusion in OZR lagged behind those in LZR, although a similar maximum reduction was ultimately attained. With increasing hemorrhage, cremasteric arteriolar tone increased more in OZR than LZR, and this increase in active tone was entirely due to an elevated adrenergic contribution. Norepinephrine-induced arteriolar constriction was greater in OZR vs. LZR under control conditions and during hemorrhage, with arterioles from OZR demonstrating early closure vs. LZR. These results suggest that a combination of reduced blood volume and elevated peripheral adrenergic constriction contribute to impaired hemorrhage tolerance in OZR.
Value of APACHE II, SOFA and CPIS Scores in Predicting Prognosis in Patients with Ventilator-Associated Pneumonia
Authors: Gursel Gul , Demirtas Senay
Published: October 2005

Background: Ventilator-associated pneumonia (VAP) is the most frequent infection with high mortality rates in intensive care units (ICUs) and the prediction of outcome is important in the decision-making process. Objective: To assess the value of the Acute Physiology and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA) and Clinical Pulmonary Infection Score (CPIS) in the prediction of mortality during VAP episodes in pulmonary patients. Methods: This study was a prospective observational cohort study. Sixty-three patients who were admitted to the ICU and developed VAP were included in the study consecutively. Clinical and laboratory data conforming to the APACHE II and SOFA scores were recorded on admission and APACHE II, SOFA and CPIS scores on the day of the diagnosis of VAP. The outcome measure was the ICU mortality. Logistic regression and receiver operating characteristic (ROC) curve analyses and the area under the curve (AUC) were used to estimate the predictive ability of the scoring systems. Results: Mortality rate was 54%. The mean APACHE II (21 ± 6, 14 ± 5; p = 0.001), SOFA (7 ± 3, 4 ± 2; p = 0.002) and CPIS (8 ± 2, 7 ± 3; p = 0.025) scores determined at the time of VAP diagnosis were significantly higher in nonsurvivors than in survivors. Discrimination was excellent for APACHE II (ROC AUC: 0.81; p = 0.001) and acceptable for SOFA (ROC AUC: 0.71; p = 0.005) scores. Of the three scores only APACHE II >16 was an independent predictor of the mortality (OR: 5; 95% CI: 1.3–18; p = 0.019) in the logistic regression analysis. Conclusion: These results suggest that APACHE II determined at the time of VAP diagnosis may be useful in predicting mortality in the pulmonary ICU patient population who develops VAP.
T.I.M.S: TaqMan Information Management System, tools to organize data flow in a genotyping laboratory
Authors: Monnier Stéphanie , Cox David G , Albion Tim , Canzian Federico
Published: October 2005

Background

Single Nucleotide Polymorphism (SNP) genotyping is a major activity in biomedical research. The Taqman technology is one of the most commonly used approaches. It produces large amounts of data that are difficult to process by hand. Laboratories not equipped with a Laboratory Information Management System (LIMS) need tools to organize the data flow.

Results

We propose a package of Visual Basic programs focused on sample management and on the parsing of input and output TaqMan files. The code is written in Visual Basic, embedded in the Microsoft Office package, and it allows anyone to have access to those tools, without any programming skills and with basic computer requirements.

Conclusion

We have created useful tools focused on management of TaqMan genotyping data, a critical issue in genotyping laboratories whithout a more sophisticated and expensive system, such as a LIMS.
Phydbac "Gene Function Predictor" : a gene annotation tool based on genomic context analysis
Authors: Enault François , Suhre Karsten , Claverie Jean-Michel
Published: October 2005

Background

The large amount of completely sequenced genomes allows genomic context analysis to predict reliable functional associations between prokaryotic proteins. Major methods rely on the fact that genes encoding physically interacting partners or members of shared metabolic pathways tend to be proximate on the genome, to evolve in a correlated manner and to be fused as a single sequence in another organism.

Results

The new "Gene Function Predictor", linked to the web server Phydbac proposes putative associations between Escherichia coli K-12 proteins derived from a combination of these methods. We show that associations made by this tool are more accurate than linkages found in the other established databases. Predicted assignments to GO categories, based on pre-existing functional annotations of associated proteins are also available. This new database currently holds 9,379 pairwise links at an expected success rate of at least 80%, the 6,466 functional predictions to GO terms derived from these links having a level of accuracy higher than 70%.

Conclusion

The "Gene Function Predictor" is an automatic tool that aims to help biologists by providing them hypothetical functional predictions out of genomic context characteristics. The "Gene Function predictor" is available at http://www.igs.cnrs-mrs.fr/phydbac/indexPS.html.
Prosthetic valve endocarditis caused by Pseudomonas luteola
Authors: Casalta Jean-Paul , Fournier Pierre-Edouard , Habib Gilbert , Riberi Alberto , Raoult Didier
Published: October 2005

Background

Pseudomonas luteola has been recognized as an uncommon cause of bacteremia and of infections in patients with underlying medical disorders

Case presentation

We isolated P. luteola from blood cutures in a patient with prosthetic valve endocarditis developed 16 months after cardiac surgery.

Conclusion

P. luteola is a rare opportunistic agent, with a propensity of infecting valvular prostheses.
Clinico-morphological patterns of breast cancer including family history in a New Delhi hospital, India-A cross-sectional study
Authors: Saxena Sunita , Rekhi Bharat , Bansal Anju , Bagga Ashok , Chintamani  , Murthy Nandagudi S
Published: October 2005

Background

Breast cancer is the second most common malignancy among women, next to cervix cancer. Understanding its pathogenesis, morphological features and various risk-factors, including family history holds a great promise for the treatment, early detection and prevention of this cancer.

Patients and methods

In an attempt to evaluate the clinico-morphological patterns of breast cancer patients, including their family history of breast and/or other cancers, a detailed analysis of 569 breast cancer cases diagnosed during the years 1989–2003 was carried out. Mean and standard deviation and Odds ratios along with 95% confidence intervals were estimated. χ2/Fisher's exact test were employed to test for proportions.

Results

Mean age of the patient at presentation was 47.8 years, ranging from 13–82 years. Among the various histo-morphological types, Infiltrating duct carcinoma (IDC) was found to be commonest type i.e. in 502 cases (88.2%), followed by infiltrating lobular carcinoma (ILC) in 21 cases (3.7%) and other types forming 9(1%). Out of 369 cases where TNM staging was available, stage IIIB (35.2%) was the commonest. Lymph node positivity was observed in 296 cases (80.2%). Out of 226 cases evaluated for presence of family history, 47 cases (20.7%) revealed positive family history of cancer, among which breast or ovarian cancer were the commonest type (72.0%). Patients below 45 years of age had more frequent occurrence of family history as compared to above 45 years. Amongst familial cases, Infiltrating duct carcinoma was the commonest form accounting for 68.8% cases while ILC was found to be in a higher proportion (12.5%) as compared to non- familial cases (5.4%).

Conclusion

Among the various determining factors for development of breast cancer and for its early detection, family history of cancer forms one of the major risk factor. It is important to take an appropriate history for eliciting information pertaining to occurrence of cancers amongst the patients' relatives there by identifying the high risk group. Educating the population about the risk factors would be helpful in early detection of breast cancer.
Association between anti-nucleophosmin and anti-cardiolipin antibodies in (NZW × BXSB)F1mice and human systemic lupus erythematosus
Authors: Lartigue Aurelia , Drouot Laurent , Jouen Fabienne , Charlionet Roland , Tron François , Gilbert Danièle
Published: October 2005

We showed previously that nucleophosmin (NPM), a nucleolar phosphoprotein, is recognized by sera from (NZW × BXSB)F1 (WB) mice, a model of systemic lupus erythematosus (SLE) and anti-phospholipid syndrome. In the present study we analysed the prevalence and kinetics of anti-NPM autoantibodies in WB mice by a solid-phase ELISA with recombinant human (rh) NPM as the antigen and showed that most male WB mouse sera had anti-NPM antibodies that were responsible for their indirect immunofluorescence staining pattern on Hep-2 cells. Anti-NPM antibodies were significantly associated with anti-cardiolipin (aCL) antibodies. This antibody profile mirrored that observed in certain human SLE sera because anti-NPM antibodies were detected in 28% of the sera from patients with SLE and were similarly associated with aCL antibodies. The demonstration that rhNPM bound to cardiolipin (CL) in vitro and increased the CL-binding activity of a WB-derived aCL monoclonal antibody indicates that NPM can interact with CL to form SLE-related immunogenic particles that might be responsible for the concomitant production of anti-NPM and aCL antibodies.
A Model of the Ingroup as a Social Resource
Authors: Correll Joshua , Park Bernadette
Published: October 2005

Drawing on theories of social comparison, realistic group conflict, and social identity, we present an integrative model designed to describe the psychological utility of social groups. We review diverse motivations that group membership may satisy (e.g., the need for acceptance or ideological consensus) and attempt to link these particular needs to a global concern for self-worth. We then examine several factors hypothesized to influence an ingroup's utility in the eyes of its members. Attempting to unite our understanding of (a) why groups are needed and (b) what kinds of groups are useful in meeting those needs, a proposed model of the ingroup as a social resource (MISR) suggests that the dimensions of perceived value, entitativity, and identification interact to determine the overall psychological utility of an ingroup. We discuss empirical and theoretical support for this model, as well as its implications for intra-and intergroup attitudes.
Temporal requirement ofHoxa2in cranial neural crest skeletal morphogenesis
Authors: Santagati Fabio , Minoux Maryline , Ren Shu-Yue , Rijli Filippo M.
Published: October 2005

Little is known about the spatiotemporal requirement of Hox gene patterning activity in vertebrates. In Hoxa2 mouse mutants, the hyoid skeleton is replaced by a duplicated set of mandibular and middle ear structures. Here,we show that Hoxa2 is selectively required in cranial neural crest cells (NCCs). Moreover, we used a Cre-ERT2 recombinase system to induce a temporally controlled Hoxa2 deletion in the mouse. Hoxa2inactivation after cranial NCC migration into branchial arches resulted in homeotic transformation of hyoid into mandibular arch skeletal derivatives,reproducing the conventional Hoxa2 knockout phenotype, and induced rapid changes in Alx4, Bapx1, Six2 and Msx1 expression patterns. Thus, hyoid NCCs retain a remarkable degree of plasticity even after their migration in the arch, and require Hoxa2 as an integral component of their morphogenetic program. Moreover, subpopulations of postmigratory NCCs required Hoxa2 at discrete time points to pattern distinct derivatives. This study provides the first temporal inactivation of a vertebrate Hox gene and illustrates Hox requirement during late morphogenetic processes.
A Drosophila model of the Niemann-Pick type C lysosome storage disease: dnpc1a is required for molting and sterol homeostasis
Authors: Huang Xun , Suyama Kaye , Buchanan JoAnn , Zhu Alan J. , Scott Matthew P.
Published: October 2005

Niemann-Pick type C (NPC) disease is a fatal autosomal-recessive neurodegenerative disorder characterized by the inappropriate accumulation of unesterified cholesterol in aberrant organelles. The disease is due to mutations in either of two genes, NPC1, which encodes a transmembrane protein related to the Hedgehog receptor Patched, and NPC2, which encodes a secreted cholesterol-binding protein. Npc1 mutant mice can be partially rescued by treatment with specific steroids. We have created a Drosophila NPC model by mutating dnpc1a, one of two Drosophila genes related to mammalian NPC1. Cells throughout the bodies of dnpc1a mutants accumulated sterol in a punctate pattern, as in individuals with NPC1 mutations. The mutants developed only to the first larval stage and were unable to molt. Molting after the normal first instar period was restored to various degrees by feeding the mutants the steroid molting hormone 20-hydroxyecdysone, or the precursors of ecdysone biosynthesis, cholesterol and 7-dehydrocholesterol. dnpc1ais normally highly expressed in the ecdysone-producing ring gland. Ring gland-specific expression of dnpc1a in otherwise mutant flies allowed development to adulthood, suggesting that the lack of ecdysone in the mutants is the cause of death. We propose that dnpc1a mutants have sterols trapped in aberrant organelles, leading to a shortage of sterol in the endoplasmic reticulum and/or mitochondria of ring gland cells, and,consequently, inadequate ecdysone synthesis.
Die quantitative Analyse von Markerproteinen im Urin Quantitative analysis of marker proteins in urine
Authors: Regeniter Axel , Scholer André , Siede Werner H.
Published: October 2005

Die Analyse von spezifischen Proteinen im zweiten Morgenurin, bezogen auf den Kreatiningehalt der Probe, erlaubt heute nicht nur den Nachweis oder den Ausschluss von Nierenerkrankungen, sondern darüber hinaus auch die Differenzierung und Verlaufskontrolle von Nephropathien.

Störungen lassen sich aufgrund ihres Markerproteinprofils in solche mit hauptsächlich glomerulärem oder tubulärem Anteil und zusätzlich in weitere Untergruppen einteilen.

Im Zusammenhang mit den Teststreifenresultaten kann die Quelle einer Blutung mit spezifischen Quotienten näher eingegrenzt und Kontaminationen können von tatsächlichen renalen Proteinurien unterschieden werden.

Eine Plausibilitätsprüfung und Interpretation der erhaltenen Ergebnisse ist unbedingt erforderlich. Da eineVielzahl von Regeln überprüft werden muss, ist eine Berechnung und Darstellung der Ergebnisse nur mit Hilfe von wissensbasierten Systemen in Kombination mit einer grafischen Befunddarstellung sinnvoll.