bluuebunny/crossref_metadata_2025 huggingface dataset:
Noise estimation in voice signals using short-term cepstral analysis
Authors: Murphy Peter J. , Akande Olatunji O.
Published: March 2007

Cepstral-based estimation is used to provide a baseline estimate of the noise level in the logarithmic spectrum for voiced speech. A theoretical description of cepstral processing of voiced speech containing aspiration noise, together with supporting empirical data, is provided in order to illustrate the nature of the noise baseline estimation process. Taking the Fourier transform of the liftered (filtered in the cepstral domain) cepstrum produces a noise baseline estimate. It is shown that Fourier transforming the low-pass liftered cepstrum is comparable to applying a moving average (MA) filter to the logarithmic spectrum and hence the baseline receives contributions from the glottal source excited vocal tract and the noise excited vocal tract. Because the estimation process resembles the action of a MA filter, the resulting noise baseline is determined by the harmonic resolution (as determined by the temporal analysis window length) and the glottal source spectral tilt. On selecting an appropriate temporal analysis window length the estimated baseline is shown to lie halfway between the glottal excited vocal tract and the noise excited vocal tract. This information is employed in a new harmonics-to-noise (HNR) estimation technique, which is shown to provide accurate HNR estimates when tested on synthetically generated voice signals.
Bottlenose dolphin (Tursiops truncatus) steady-state evoked responses to multiple simultaneous sinusoidal amplitude modulated tones
Authors: Finneran James J. , Houser Dorian S.
Published: March 2007

Auditory steady-state evoked potentials were measured in a bottlenose dolphin (Tursiops truncatus) in response to single and multiple sinusoidal amplitude modulated (SAM) tones. Tests were conducted in air using a “jawphone” sound projector. Evoked potentials were recorded noninvasively using surface electrodes embedded in suction cups. Sound stimuli consisted of SAM tones with 1, 2, 3, or 4 carrier frequencies (10, 20, 30, 40kHz), each with a unique modulation frequency. Stimulus sound pressure levels were varied in 5-dB steps from approximately 120 to 60–75dB re 1μPa, depending on frequency. Evoked potentials followed the temporal envelope of each stimulus, resulting in spectral components at each unique modulation frequency. Spectral analysis was used to evaluate the response amplitude for each carrier as a function of stimulus level. There were no significant differences between thresholds obtained with single and multiple stimuli at 10, 30, and 40kHz. At 20kHz, thresholds obtained with three components were higher than those obtained with four components, possibly revealing interactions between stimuli with less than one octave frequency separation. The use of multiple SAM stimuli may offer substantial advantages for studies of marine mammal hearing, where testing time and access to subjects are typically limited.
Modeling binaural loudness
Authors: Moore Brian C. J. , Glasberg Brian R.
Published: March 2007

A survey of data on the perception of binaurally presented sounds indicates that loudness summation across ears is less than perfect; a diotic sound is less than twice as loud as the same sound presented monaurally. The loudness model proposed by Moore et al. [J. Audio Eng. Soc. 45, 224–240 (1997)] determines the loudness of binaural stimuli by a simple summation of loudness across ears. It is described here how the model can be modified so as to give more accurate predictions of the loudness of binaurally presented sounds, including cases where the sounds at the two ears differ in level, frequency or both. The modification is based on the idea that there are inhibitory interactions between the internal representations of the signals at the two ears, such that a signal at the left ear inhibits (reduces) the loudness evoked by a signal at the right ear, and vice versa. The inhibition is assumed to spread across frequency channels. The modified model gives reasonably accurate predictions of a variety of data on the loudness of binaural stimuli, including data obtained using loudness scaling and loudness matching procedures.
Acoustic power calibration of high-intensity focused ultrasound transducers using a radiation force technique
Authors: Maruvada Subha , Harris Gerald R. , Herman Bruce A. , King Randy L.
Published: March 2007

To address the challenges associated with measuring the ultrasonic power from high-intensity focused ultrasound transducers via radiation force, a technique based on pulsed measurements was developed and analyzed. Two focused ultrasound transducers were characterized in terms of an effective duty factor, which was then used to calculate the power during the pulse at high applied power levels. Two absorbing target designs were used, and both gave comparable results and displayed no damage and minimal temperature rise if placed near the transducer and away from the focus. The method yielded reproducible results up to the maximum pulse power generated of approximately 230W, thus allowing the radiated power to be calibrated in terms of the peak-to-peak voltage applied to the transducer.
Across-frequency pitch discrimination interference between complex tones containing resolved harmonics
Authors: Micheyl Christophe , Oxenham Andrew J.
Published: March 2007

Pitch discrimination interference (PDI) refers to an impairment in the ability to discriminate changes in the fundamental frequency (F0) of a target harmonic complex, caused by another harmonic complex (the interferer) presented simultaneously in a remote spectral region. So far, PDI has been demonstrated for target complexes filtered into a higher spectral region than the interferer and containing no peripherally resolved harmonics in their passband. Here, it is shown that PDI also occurs when the target harmonic complex contains resolved harmonics in its passband (experiment 1). PDI was also observed when the target was filtered into a lower spectral region than that of the interferer (experiment 2), revealing that differences in relative harmonic dominance and pitch salience between the simultaneous target and the interferer, as confirmed using pitch matches (experiment 3), do not entirely explain PDI. When the target was in the higher spectral region, and the F0 separation between the target and the interferer was around 7% or 10%, dramatic PDI effects were observed despite the relatively large F0 separation between the two sequential targets (14%–20%). Overall, the results suggest that PDI is more general than previously thought, and is not limited to targets consisting only of unresolved harmonics.
Echo-intensity compensation in echolocating bats (Pipistrellus abramus) during flight measured by a telemetry microphone
Authors: Hiryu Shizuko , Hagino Tomotaka , Riquimaroux Hiroshi , Watanabe Yoshiaki
Published: March 2007

An onboard microphone (Telemike) was developed to examine changes in the basic characteristics of echolocation sounds of small frequency-modulated echolocating bats, Pipistrellus abramus. Using a dual high-speed video camera system, spatiotemporal observations of echolocation characteristics were conducted on bats during a landing flight task in the laboratory. The Telemike allowed us to observe emitted pulses and returning echoes to which the flying bats listened during flight, and the acoustic parameters could be precisely measured without traditional problems such as the directional properties of the recording microphone and the emitted pulse, or traveling loss of the sound in the air. Pulse intensity in bats intending to land exhibited a marked decrease by 30dB within 2m of the target wall, and the reduction rate was approximately 6.5dB per halving of distance. The intensity of echoes returning from the target wall indicated a nearly constant intensity (−42.6±5.5dB weaker than the pulse emitted in search phase) within a target distance of 2m. These findings provide direct evidence that bats adjust pulse intensity to compensate for changes in echo intensity to maintain a constant intensity of the echo returned from the approaching target at an optimal range.
Characteristics of penalty mode scattering by rigid splices in lined ducts
Authors: Bi WenPing , Pagneux Vincent , Lafarge Denis , Aurégan Yves
Published: March 2007

In lined ducts, incident modes are scattered by axially and circumferentially nonuniform impedance. Experiments and numerical calculations have proved that this mode scattering can reduce the liner performance in some cases. This paper is devoted to the characterization of the penalty mode scattering excited by hard-walled splices which often exist in lined ducts. It is shown that, in the range of small splice angles, the transmission loss may decrease sharply with increasing splice angle when one mode, which is near cut-off or has high azimuthal order, is incident. When the incident sound field is composed of several acoustical modes, the phase interferences of incident modes are important for the penalty mode scattering. The effects of other parameters, e.g., liner length, mode quasiresonance on the penalty mode scattering are also presented.
Imaging with unfocused regions of focused ultrasound beams
Authors: Zemp Roger , Insana Michael F.
Published: March 2007

This article gives an analytical, computational, and experimental treatment of the spatial resolution encoded in unfocused regions of focused ultrasound beams. This topic is important in diagnostic ultrasound since ultrasound array systems are limited to a single transmit focal point per acoustic transmission, hence there is a loss of spatial resolution away from the transmit focus, even with the use of dynamic receive focusing. It is demonstrated that the spatial bandwidth of a Gaussian-apodized beam is approximately constant with depth, which means that there is just as much encoded spatial resolution away from the transmit focus as there is in the focal region. The practical application of this principle is discussed, an algorithm for retrospectively focusing signals from unfocused regions of fixed-focus beams is presented, and a quantitative comparison between the authors' methods and dynamic-receive beamforming is provided.
Examination of bone-conducted transmission from sound field excitation measured by thresholds, ear-canal sound pressure, and skull vibrations
Authors: Reinfeldt Sabine , Stenfelt Stefan , Good Tobias , Håkansson Bo
Published: March 2007

Bone conduction (BC) relative to air conduction (AC) sound field sensitivity is here defined as the perceived difference between a sound field transmitted to the ear by BC and by AC. Previous investigations of BC-AC sound field sensitivity have used different estimation methods and report estimates that vary by up to 20dB at some frequencies. In this study, the BC-AC sound field sensitivity was investigated by hearing threshold shifts, ear canal sound pressure measurements, and skull bone vibrations measured with an accelerometer. The vibration measurement produced valid estimates at 400Hz and below, the threshold shifts produced valid estimates at 500Hz and above, while the ear canal sound pressure measurements were found erroneous for estimating the BC-AC sound field sensitivity. The BC-AC sound field sensitivity is proposed, by combining the present result with others, as frequency independent at 50 to 60dB at frequencies up to 900Hz. At higher frequencies, it is frequency dependent with minima of 40 to 50dB at 2 and 8kHz, and a maximum of 50 to 60dB at 4kHz. The BC-AC sound field sensitivity is the theoretical limit of maximum attenuation achievable with ordinary hearing protection devices.
Comment on “The directionality of acoustic T-phase signals from small magnitude submarine earthquakes” [J. Acoust. Soc. Am. 119, 3669–3675 (2006)]
Authors: Bohnenstiehl Delwayne R.
Published: March 2007

In a recent paper, Chapman and Marrett [J. Acoust. Soc. Am. 119, 3669–3675 (2006)] examined the tertiary (T-) waves associated with three subduction-related earthquakes within the South Fiji Basin. In that paper it is argued that acoustic energy is radiated into the sound channel by downslope propagation along abyssal seamounts and ridges that lie distant to the epicenter. A reexamination of the travel-time constraints indicates that this interpretation is not well supported. Rather, the propagation model that is described would require the high-amplitude T-wave components to be sourced well to the east of the region identified, along a relatively flat-lying seafloor.
Sound pressure level and spectral balance linearity and symmetry in the messa di voce of female classical singers
Authors: Collyer Sally , Davis Pamela J. , Thorpe C. William , Callaghan Jean
Published: March 2007

The messa di voce, in its pure form a crescendo and decrescendo on one note, has been revered for centuries in classical singing, but the pedagogical assumptions of linearity and symmetry have received little critical assessment, especially across a wide fundamental frequency (F0) range. Five trained female classical singers performed a total of 318 messe di voce across their musical F0 range to identify its acoustical characteristics and the influence of F0. Sound pressure level (SPL) range was generally greater during crescendo at higher F0’s and during decrescendo at lower F0’s. Change in SPL during the messa di voce was predominantly nonlinear, and the shape of the SPL traces differed greatly between crescendo and decrescendo. Nonlinearity in SPL change was not related to SPL range but did show a F0 influence in decrescendo. Change in spectral balance (0–2 vs 2–4kHz) with respect to SPL change showed markedly more symmetry than linearity, so that changes in the mode of phonation during the messa di voce were dependent upon SPL regardless of whether the singer was in crescendo or decrescendo. Perceptual and physiological implications are discussed.
The perception of complex tones by a false killer whale (Pseudorca crassidens)
Authors: Yuen Michelle M. L. , Nachtigall Paul E. , Breese Marlee , Vlachos Stephanie A.
Published: March 2007

Complex tonal whistles are frequently produced by some odontocete species. However, no experimental evidence exists regarding the detection of complex tones or the discrimination of harmonic frequencies by a marine mammal. The objectives of this investigation were to examine the ability of a false killer whale to discriminate pure tones from complex tones and to determine the minimum intensity level of a harmonic tone required for the whale to make the discrimination. The study was conducted with a go∕no-go modified staircase procedure. The different stimuli were complex tones with a fundamental frequency of 5kHz with one to five harmonic frequencies. The results from this complex tone discrimination task demonstrated: (1) that the false killer whale was able to discriminate a 5kHz pure tone from a complex tone with up to five harmonics, and (2) that discrimination thresholds or minimum intensity levels exist for each harmonic combination measured. These results indicate that both frequency level and harmonic content may have contributed to the false killer whale’s discrimination of complex tones.
Gray whale target strength measurements and the analysis of the backscattered response
Authors: Lucifredi Irena , Stein Peter J.
Published: March 2007

One of the current Integrated Marine Mammal Monitoring and Protection System (IMPAS) directions is concentrated on the design and development of the active sonar modality representing just one component of the global system. The active sonar was designed, built, and tested during the Marine Mammal Active Sonar Test (MAST 04), producing whale detections and whale tracks. The experiment was conducted in January 2004 off the coast of California. One of the objectives of the current work is to distinguish whale backscattered responses from the ones generated by the environmental clutter in a waveguide. Furthermore, the work aims to identify and analyze the target signature features that are necessary for enhanced active sonar detection and classification of marine mammals. Over the years there have been very few documented attempts to capture and analyze the backscattering response of whales using an active sonar system. Nevertheless, whales, mostly owing to their size, their motion, and the aspect dependence of their backscattered field, possess desirable properties that help distinguish their scattered response from clutter and other environment related false alarms. As an initial step, data collected during the MAST 04 experiment are presented, and gray whale target strength measurements are obtained. Results are compared to the previously published whale target strengths. Additionally, an investigation is conducted in an effort to provide whale feature identification points suitable for automated detection and classification, as means of relating gray whale active acoustic signatures to their inherent characteristics and their motion.
Noncontact transportation in water using ultrasonic traveling waves
Authors: Nomura Shinfuku , Matula Thomas J. , Satonobu Jun , Crum Lawrence A.
Published: March 2007

A noncontact transport experiment in water using ultrasonic traveling waves was investigated. Acrylic, aluminum, and brass discs were used as test objects. Traveling waves were generated using two ultrasonic transducers attached at the ends of a vibrating plate. One side was used as the wave-source side and the other side was used as the wave-receiving side. Acrylic plates cemented to the sides of the vibrating plate formed a tank to hold water. Object transportation was accomplished by adding a small amount of water to the vibrating structure. The transport velocity of floating objects in water is faster than for floating transport in air because of buoyancy. The transport velocity of an object depends on water height. The minimum value of the velocity occurs when the disc thickness is equal to the water height. The transport velocity increases as the height of water increases. For very shallow depths, the largest velocity is obtained when cavitation-induced streaming occurs.
Acoustic micro-Doppler radar for human gait imaging
Authors: Zhang Zhaonian , Pouliquen Philippe O. , Waxman Allen , Andreou Andreas G.
Published: March 2007

A portable acoustic micro-Doppler radar system for the acquisition of human gait signatures in indoor and outdoor environments is reported. Signals from an accelerometer attached to the leg support the identification of the components in the measured micro-Doppler signature. The acoustic micro-Doppler system described in this paper is simpler and offers advantages over the widely used electromagnetic wave micro-Doppler radars.
Ultrasonic wave generation due to human footsteps on the ground
Authors: Ekimov Alexander , Sabatier James M.
Published: March 2007

Human footsteps generate broadband frequency vibrations in the ground/floor and sound in the air from a few Hertz up to ultrasonic frequencies due to striking and sliding contacts between a foot and the ground/floor. The high-frequency (above 1kHz) vibrations from footsteps were detected on a building floor, but were not detected on the outdoor ground, even at 1m from a walker. This paper presents results of ultrasound registration from footsteps on the ground at greater distances. Results are based on sound measurements in air, since the sound absorption in air is less than vibration absorption in the ground.
Modulation of Gamma Interferon Receptor 1 byMycobacterium tuberculosis: a Potential Immune Response Evasive Mechanism
Authors: Singhal Amit , Jaiswal Anand , Arora Virendra K. , Prasad Hanumanthappa K.
Published: March 2007

Mycobacterium tuberculosisinhibits gamma interferon (IFN-γ)-mediated antimycobacterial action by adopting diverse mechanisms. IFN-γ binds to its receptor, IFN-γR, in order to initiate proper signaling. We have observed reduced surface expression levels of IFN-γ receptor 1 (IFN-γR1) in untreated pulmonary tuberculosis patients compared to those in healthy individuals (P< 0.01). Following antitubercular therapy, the expression of IFN-γR1 was restored in these patients. To delineate the mechanism by whichM. tuberculosismodulates IFN-γR1, in vitro experiments were designed, wherein the down modulation of IFN-γR1 surface expression was observed for CD14+cells in peripheral blood mononuclear cells (PBMCs) cocultured with liveM. tuberculosiscompared to that for uninfected cells (P< 0.01). No modulation of IFN-γR1 expression was observed for CD14+cells in PBMCs infected withMycobacterium smegmatis. A time-dependent decrease in IFN-γR1 mRNA expression was observed for PBMCs infected withM. tuberculosis. Similar down modulation of IFN-γR1 protein and mRNA expression in phorbol myristate acetate-differentiated THP-1 cells (pdTHP-1) byM. tuberculosiswas observed (P< 0.01). Using reporter gene analysis of 5′ deletion constructs of the IFN-γR1 gene (IFNGR1) promoter, the decrease in IFN-γR1 mRNA inM. tuberculosis-infected pdTHP-1 cells was shown to be due to the decreased transcription ofIFNGR1. By immunoblotting and electrophoretic mobility shift assays, the down regulation of stimulating protein 1 (Sp1) expression and its recruitment on the phorbol ester-responsive element of theIFNGR1promoter inM. tuberculosis-infected pdTHP-1 cells was observed. This down regulation of Sp1 in pdTHP-1 cells cocultured withM. tuberculosismay be responsible for the down regulation of IFN-γR1 expression, thereby potentially altering its receptivity to IFN-γ.
Anthrax Edema Toxin Sensitizes DBA/2J Mice to Lethal Toxin
Authors: Firoved Aaron M. , Moayeri Mahtab , Wiggins Jason F. , Shen Yuequan , Tang Wei-Jen , Leppla Stephen H.
Published: March 2007

Anthrax toxin is made up of three separate protein components: the receptor-binding protective antigen (PA), the adenylyl cyclase edema factor (EF), and the metalloproteinase lethal factor (LF). EF and PA constitute edema toxin (ET), which causes edema when injected subcutaneously. At higher doses, ET causes severe pathologies and death in BALB/cJ mice (A. M. Firoved et al., Am. J. Pathol. 167:1309-1320, 2005). A striking effect of ET at lethal doses is adrenal necrosis. Here we show that low doses of ET (10 μg) that produce no overt signs of illness in mice still cause substantial adrenal lesions. These lesions are not associated with reduced corticosterone production; instead, ET-treated mice have increased corticosterone production. Because the resistance of mice to the other component of anthrax toxin, lethal toxin (LT; LF plus PA), has been shown to be overcome by the perturbation of the endocrine system, we hypothesized that sublethal doses of ET might sensitize LT-resistant DBA/2J mice to LT-mediated lethality. We report that a low dose of ET (5 μg) is sufficient to sensitize DBA/2J mice when given concurrently with LT. Higher doses of ET (e.g., 15 μg) given to male and female DBA/2J mice 18 h prior to LT challenge also sensitize them to LT. This study using highly purified ET and LT demonstrates how the components of anthrax toxin can work together to increase lethality.
An In Vitro Model System Used To Study Adherence and Invasion of
Francisella tularensis
Live Vaccine Strain in Nonphagocytic Cells
Authors: Lindemann Stephen R. , McLendon Molly K. , Apicella Michael A. , Jones Bradley D.
Published: March 2007

In observing
Francisella tularensis
interactions with nonphagocytic cell lines in vitro, we noted significant adherence, invasion, and intracellular growth of the bacteria within these cells.
F. tularensis
live vaccine strain invasion of nonprofessional phagocytic cells is inhibited by cytochalasin D and nocodazole, suggesting that both the actin and microtubule cytoskeletons are important for invasion.
Shigella flexneri
Inhibits Staurosporine-Induced Apoptosis in Epithelial Cells
Authors: Clark Christina S. , Maurelli Anthony T.
Published: March 2007

Shigella flexneri
is a facultative intracellular organism that causes bacillary dysentery. The
Shigella
IpaB protein activates caspase 1 in macrophages, which eventually leads to apoptosis. In contrast, epithelial cells infected with
Shigella
undergo a stress response but do not die. Therefore, the objective of this study was to determine if
Shigella
has the ability to inhibit apoptosis in epithelial cells. A modified gentamicin protection assay was used to investigate if HeLa cells infected with
S. flexneri
are able to resist the induction of apoptosis following treatment with 4 μM of staurosporine. Nuclear staining and immunofluorescence revealed that infected cells remained healthy while uninfected cells appeared apoptotic. Only uninfected cells had detectable levels of activated caspase 3 upon immunofluorescence, and this was verified by Western blot analysis. Despite interfering with caspase 3 activation,
Shigella
-infected cells treated with staurosporine did have cytochrome
c
release and caspase 9 activation, indicating that
Shigella
protects epithelial cells from apoptosis by inhibiting caspase 3 activation. Analysis of
S. flexneri
mutants showed that invasion and a functional type III secretion system were required to block apoptosis. In addition, a mutant with a deletion in
mxiE
, which encodes a transcriptional activator for genes induced intracellularly, failed to inhibit apoptosis. Therefore, protection of epithelial cells from apoptosis by
S. flexneri
is regulated by one or more of the bacterial genes under the control of
mxiE
. We believe that
S. flexneri
, like other pathogens, inhibits apoptosis in epithelial cells but causes apoptosis in macrophages to ensure survival inside the host.
Flow Cytometric Analysis of Adherence of
Porphyromonas gingivalis
to Oral Epithelial Cells
Authors: Pathirana Rishi D. , O'Brien-Simpson Neil M. , Visvanathan Kumar , Hamilton John A. , Reynolds Eric C.
Published: March 2007

By using fluorescence microscopy, fluorescently labeled
Porphyromonas gingivalis
W50 was shown to adhere to oral epithelial (KB) cells as discrete cells or small cell aggregates, whereas
P. gingivalis
ATCC 33277 bound as large cell aggregates. Flow cytometric analysis showed that for
P. gingivalis
W50 there was a logarithmic relationship between the bacterial cell ratio (BCR), that is the number of bacterial cells to KB cells, and the percentage of KB cells with W50 cells attached. This percentage of KB cells with W50 attached reached a plateau of ∼84% cells at a BCR of 500:1. In contrast, a quadratic relationship was observed between BCR and the percentage of KB cells with
P. gingivalis
ATCC 33277 attached, reaching a maximum of 47% at a BCR of 100:1 but decreasing to 7% at a BCR of 1,000:1. The lower binding of ATCC 33277 at high cell concentrations was attributed to autoaggregation.
P. gingivalis
W50 cells treated with an inhibitor (
N
α-
p
-tosyl-
l
-lysine chloromethyl ketone [TLCK]) of its RgpA-Kgp proteinase-adhesin complex exhibited significantly reduced binding to KB cells than to untreated cells, suggesting a role for proteinase activity in binding to KB cells. Competitive inhibition with purified proteinase-active and TLCK-inactivated RgpA-Kgp complex significantly decreased the adherence of
P. gingivalis
W50 cells to KB cells. Furthermore, isogenic mutants of
P. gingivalis
W50 lacking the
kgp
gene product, but not the
rgpA
or
rgpB
gene products, exhibited significantly decreased adherence to KB cells compared to the wild type.
C-LOOPS: EXTENSIONS AND CONSTRUCTIONS
Authors: KINYON MICHAEL K. , PHILLIPS J. D. , VOJTĚCHOVSKÝ PETR
Published: March 2007

C-loops are loops satisfying the identity x(y · yz) = (xy · y)z. We develop the theory of extensions of C-loops, and characterize all nuclear extensions provided the nucleus is an abelian group. C-loops with central squares have very transparent extensions; they can be built from small blocks arising from the underlying Steiner triple system. Using these extensions, we decide for which abelian groups K and Steiner loops Q there is a nonflexible C-loop C with center K such that C/K is isomorphic to Q. We discuss possible orders of associators in C-loops. Finally, we show that the loops of signed basis elements in the standard real Cayley–Dickson algebras are C-loops.
FREE AUGMENTED LD-SYSTEMS
Authors: DEHORNOY PATRICK
Published: March 2007

Define an augmented LD-system, or ALD-system, to be a set equipped with two binary operations, one satisfying the left self-distributivity law x * (y * z) = (x * y) * (x * z) and the other satisfying the mixed laws (x ◦ y) * z = x * (y * z) and x * (y ◦ z) = (x * y) ◦ (x * z). We solve the word problem of the ALD laws, and prove that every element in the parenthesized braid group B• of [2, 3, 5, 6] generates a free ALD-system of rank 1, i.e., that B• is a torsion-free ALD-system.
THE CHRONO-GEOMETRICAL STRUCTURE OF SPECIAL AND GENERAL RELATIVITY: A RE-VISITATION OF CANONICAL GEOMETRODYNAMICS
Authors: LUSANNA LUCA
Published: March 2007

A modern re-visitation of the consequences of the lack of an intrinsic notion of instantaneous 3-space in relativistic theories leads to a reformulation of their kinematical basis emphasizing the role of non-inertial frames centered on an arbitrary accelerated observer. In special relativity the exigence of predictability implies the adoption of the 3 + 1 point of view, which leads to a well posed initial value problem for field equations in a framework where the change of the convention of synchronization of distant clocks is realized by means of a gauge transformation. This point of view is also at the heart of the canonical approach to metric and tetrad gravity in globally hyperbolic asymptotically flat space-times, where the use of Shanmugadhasan canonical transformations allows the separation of the physical degrees of freedom of the gravitational field (the tidal effects) from the arbitrary gauge variables. Since a global vision of the equivalence principle implies that only global non-inertial frames can exist in general relativity, the gauge variables are naturally interpreted as generalized relativistic inertial effects, which have to be fixed to get a deterministic evolution in a given non-inertial frame. As a consequence, in each Einstein's space-time in this class the whole chrono-geometrical structure, including also the clock synchronization convention, is dynamically determined and a new approach to the Hole Argument leads to the conclusion that "gravitational field" and "space-time" are two faces of the same entity. This view allows to get a classical scenario for the unification of the four interactions in a scheme suited to the description of the solar system or our galaxy with a deparametrization to special relativity and the subsequent possibility to take the non-relativistic limit.
DARK ENERGY MODELS TOWARD OBSERVATIONAL TESTS AND DATA
Authors: CAPOZZIELLO SALVATORE
Published: March 2007

A huge amount of good quality astrophysical data converges towards the picture of a spatially flat universe undergoing the today observed phase of accelerated expansion. This new observational trend is commonly addressed as Precision Cosmology. Despite of the quality of astrophysical surveys, the nature of dark energy dominating the matter-energy content of the universe is still unknown and a lot of different scenarios are viable candidates to explain cosmic acceleration. Methods to test these cosmological models are based on distance measurements and lookback time toward astronomical objects used as standard candles. I discuss the characterizing parameters and constraints of three different classes of dark energy models pointing out the related degeneracy problem which is the signal that more data at low (z ~ 0 ÷ 1), medium (1 < z < 10) and high (10 < z < 1000) redshift are needed to definitively select realistic models.
DARK MATTER AND DARK ENERGY AS EFFECTS OF MODIFIED GRAVITY
Authors: BOROWIEC ANDRZEJ , GODŁOWSKI WŁODZIMIERZ , SZYDŁOWSKI MAREK
Published: March 2007

We explain the effect of dark matter (flat rotation curve) using modified gravitational dynamics. We investigate in this context a low energy limit of generalized general relativity with a nonlinear Lagrangian [Formula: see text], where R is the (generalized) Ricci scalar and n is parameter estimated from SNIa data. We estimate parameter β in modified gravitational potential [Formula: see text]. Then we compare value of β obtained from SNIa data with β parameter evaluated from the best fitted rotation curve. We find β ≃ 0.7 which becomes in good agreement with an observation of spiral galaxies rotation curve. We also find preferred value of Ωm,0 from the combined analysis of supernovae data and baryon oscillation peak. We argue that although amount of "dark energy" (of non-substantial origin) is consistent with SNIa data and flat curves of spiral galaxies are reproduces in the framework of modified Einstein's equation we still need substantial dark matter. For comparison predictions of the model with predictions of the ΛCDM concordance model we apply the Akaike and Bayesian information criteria of model selection.
Surfactant dysfunction and lung injury due to theE. colivirulence factor hemolysin in a rat pneumonia model
Authors: Russo Thomas A. , Wang Zhengdong , Davidson Bruce A. , Genagon Stacy A. , Beanan Janet M. , Olson Ruth , Holm Bruce A. , Knight Paul R. , Chess Patricia R. , Notter Robert H.
Published: March 2007

This study tests the hypothesis that the virulence factor hemolysin (Hly) expressed by extraintestinal pathogenic Escherichia coli contributes to surfactant dysfunction and lung injury in a rat model of gram-negative pneumonia. Rats were instilled intratracheally with CP9 (wild type, Hly-positive), CP9 hlyA (Hly-minus), CP9 /pEK50 (supraphysiological Hly), or purified LPS. At 6 h postinfection, rats given CP9 had a decreased percentage content of large surfactant aggregates in cell-free bronchoalveolar lavage (BAL), decreased large aggregate surface activity, decreased PaO2/FiO2ratio, increased BAL albumin/protein levels, and increased histological evidence of lung injury compared with rats given CP9 hlyA or LPS. In addition, rats given CP9/ pEK50 or CP9 had decreased large aggregate surface activity, decreased PaO2/FiO2ratios, and increased BAL albumin/protein levels at 2 h postinfection compared with rats given CP9 hlyA. The severity of permeability lung injury based on albumin/protein levels in BAL at 2 h was ordered as CP9 /pEK50 > CP9 > CP9 hlyA > normal saline controls. Total lung titers of bacteria were increased at 6 h in rats given CP9 vs. CP9 hlyA, but bacterial titers were not significantly different at 2 h, indicating that increased surfactant dysfunction and lung injury were associated with Hly as opposed to bacterial numbers per se. Further studies in vitro showed that CP9 could directly lyse transformed pulmonary epithelial cells (H441 cells) but that indirect lysis of H441 cells secondary to Hly-induced neutrophil lysis did not occur. Together, these data demonstrate that Hly is an important direct mediator of surfactant dysfunction and lung injury in gram-negative pneumonia.
Adenosine enhances cytosolic phosphorylation potential and ventricular contractility in stunned guinea pig heart: receptor-mediated and metabolic protection
Authors: Schulze Karsten , Duschek Conrad , Lasley Robert D. , Bünger Rolf
Published: March 2007

Mechanisms of adenosine (ADO) protection of reperfused myocardium are not fully understood. We tested the hypothesis that ADO (0.1 mM) alleviates ventricular stunning by ADO A1-receptor stimulation combined with purine metabolic enhancements. Langendorff guinea pig hearts were stunned at constant left ventricular end-diastolic pressure by low-flow ischemia. Myocardial phosphate metabolites were measured by31P-NMR, with phosphorylation potential {[ATP]/([ADP]·[Pi]), where brackets indicate concentration} estimated from creatine kinase equilibrium. Creatine and IMP, glycolytic intermediates, were measured enzymatically and glycolytic flux and extracellular spaces were measured by radiotracers. All treatment interventions started after a 10-min normoxic stabilization period. At 30 min reperfusion, ventricular contractility (dP/d t, left ventricular pressure) was reduced 17–26%, ventricular power (rate-pressure product) by 37%, and [ATP]/([ADP]·[Pi]) by 53%. The selective A1agonist 2-chloro- N6-cyclo-pentyladenosine marginally preserved [ATP]/([ADP]·[Pi]) and ventricular contractility but not rate-pressure product. Purine salvage precursor inosine (0.1 mM) substantially raised [ATP]/([ADP]·[Pi]) but weakly affected contractility. The ATP-sensitive potassium channel blocker glibenclamide (50 μM) abolished ADO protection of [ATP]/([ADP]·[Pi]) and contractility. ADO raised myocardial IMP and glucose-6-phosphate, demonstrating increased purine salvage and pentose phosphate pathway flux potential. Coronary hyperemia alone (papaverine) was not cardioprotective. We found that ADO protected energy metabolism and contractility in stunned myocardium more effectively than both the A1-receptor agonist 2-chloro- N6-cyclo-pentyladenosine and the purine salvage precursor inosine. Because ADO failed to stimulate glycolytic flux, the enhancement of reperfusion, [ATP]/([ADP]·[Pi]), indicates protection of mitochondrial function. Reduced ventricular dysfunction at enhanced [ATP]/([ADP]·[Pi]) argues against opening of mitochondrial ATP-sensitive potassium channel. The results establish a multifactorial mechanism of ADO antistunning, which appears to combine ADO A1-receptor signaling with metabolic adenylate and antioxidant enhancements.
A Solution for Universal Classification of Species Based on Genomic DNA
Authors: Kouduka Mariko , Sato Daisuke , Komori Manabu , Kikuchi Motohiro , Miyamoto Kiyoshi , Kosaku Akinori , Naimuddin Mohammed , Matsuoka Atsushi , Nishigaki Koichi
Published: March 2007

Traditionally, organisms have been classified on the basis of their phenotype. Recently, genotype-based classification has become possible through the development of sequencing technology. However, it is still difficult to apply sequencing approaches to the analysis of a large number of species due to the cost and labor. In most biological fields, the analysis of complex systems comprising various species has become an important theme, demanding an effective method for handling a vast number of species. In this paper, we have demonstrated, using plants, fish, and insects, that genome profiling, a compact technology for genome analysis, can classify organisms universally. Surprisingly, in all three of the domains of organisms tested, the phylogenetic trees generated from the phenotype topologically matched completely those generated from the genotype. Furthermore, a single probe was sufficient for the genome profiling, thereby demonstrating that this methodology is universal and compact.
Synthesis, Spectroscopic and Toxicity Studies ofTitanocene Chelates of Isatin‐3‐Thiosemicarbazones
Authors: Vatsa Garima , Pandey O. P. , Sengupta S. K.
Published: March 2007

The reactions of bis(cyclopentadienyl)titanium(IV) dichloride with a new class of thiosemicarbazone
(LH2), derived by condensing isatin with different N(4)‐substituted thiosemicarbazides, have been studied
and products of type [Cp2Ti(L)] have been isolated. On the basis of various physico‐chemical and spectral
studies, five coordinate structures have been assigned to these derivatives. Toxicity studies of titanocene
complexes at tbur different concentrations have been carried out against snail Lymnaea acuminata. The
effect of most potent compounds on the activity of acetylcholinesterase enzyme, which inhibits the activity of
enzyme, possibly by the formation of enzyme‐inhibitor complex, was also studied.
Potentially Biodynamic Tetraaza Macrocycles and theirManganese Complexes: Antiandrogen, Antimicrobialand PDI Studies
Authors: Chaudhary Ashu , Phor Anita , Singh R. V.
Published: March 2007

Fourteen to eighteen membered tetraazamacrocyclic ligands N4TTD1–N4TTD4 have been synthesized by
the condensation of aliphatic diamines. H2N–(CH2)y–NH2 (y = 2 or 3) and dicarboxylic acids, HOOC‐
(CH2)x–COOH (x = 1 or 2) in the presence of condensing reagents dicyclohexylcarbodiimide (DCHC) and 4‐
dimethylaminopyridine (DMAP). On reduction these macrocyclic ligands give N4TTD5‐N4TTD8, which form
complexes with manganese(II) acetate. The new products with octahedral geometry have been characterized
by elemental analyses, molecular weight determinations, magnetic moment and spectral studies viz., infrared,
electronic, mass and X‐ray. On the basis of the spectral studies the binding sites are proposed as the nitrogen
atom of the macrocycles. The formulation of the complexes as [Mn(CH3COO)2(N4TTDn)] (where n = 1 ‐ 8)
has been established on the basis of chemical composition. To assess the growth inhibiting potential of the
ligands and their manganese (II) complexes biological screening have been undertaken. The testicular
morphology, testicular sperm density, sperm motility, density of cauda epididymal spermatozoa and fertility
in mating trials and biochemical parameters of reproductive organs with ligands and their corresponding
complexes, in vivo have also been described in the this communication.
Novel Biologically Potent Diorganosilicon(IV) Complexesof Indole‐2,3‐Dione Derivatives
Authors: Singh R. V. , Nagpal Pooja
Published: March 2007

The aim of the present study is to synthesize some novel ecofriendly fungicides and bactericides of
indole‐2,3‐dione derivatives, having important pharmacodynamic significance. The ligands used in the
present account are derived by the condensation of 1,3‐dihydro‐3‐[2‐(phenyl)‐2‐oxoethylidene]‐2H‐indol‐2‐
one, 1,3‐dihydro‐3‐[2‐(4‐nitrophenyl)‐2‐oxoethylidene]‐2H‐indol‐2‐one and 1,3‐dihydro‐3‐[2‐(4‐nitro‐3‐methylphenyl)‐
2‐oxoethylidene]‐2H‐indol‐2‐one with hydrazinecarboxamide and hydrazinecarbothioamide. These
imines, on interaction with diorganosilicon(IV) chlorides, yield complexes having Si–O or Si–S and Si←N
bonds. The structure of these compounds have been elucidated by elemental microanalyses and spectral
[(UV), (IR), 1H, 13C and 29Si NMR)] studies which unerringly point to a trigonal bipyramidal and octahedral
geometries for unimolar and bimolar reactions, respectively. The potency of the synthesized compounds have
been assessed by growth inhibiting potential of the complexes against variety of fungal and bacterial strains
and male albino rats. The results of these biological studies have been compared with the standard fungicide,
Bavistin. The studies demonstrate that, 1,3‐dihydro‐3‐[2‐(4‐nitrophenyl)‐2‐oxoethylidene]‐2H‐indol‐2‐onehydrazincarbothioamide
and its diphenylsilicon(IV) complexes have comparable antimicrobial activity and
are less toxic to male albino rats than Bavistin.
Synthesis, Spectral and Antimicrobial Studies ofBis(cyclopentadienyl)titanium(IV) Derivativeswith Schiff Bases Derived from 2‐Amino‐5‐phenyl‐1,3,4‐thiadiazole
Authors: Srivastava A. K. , Pandey O. P. , Sengupta S. K.
Published: March 2007

The reactions of bis(cyclopentadienyl)titanium(IV) dichloride with Schiff bases derived by condensing 2‐
amino‐5‐phenyl‐1,3,4‐thiadiazole with benzaldehyde (SPT), 4‐nitrobenzaldehyde (SNT), 4‐methoxybenzaldehyde (SMT), 2‐hydroxybenzaldehyde (SSTH) or 2‐hydroxyacetophenone (SATH) have
been studied in refluxing tetrahydrofuran and complexes of types [Cp2TiCl(SB)]Cl (SB= SPT, SNT or SMT)
and [Cp2Ti(SB′)]Cl (SB′H= SSTH or SATH) have been isolated. Tentative structural conclusions are drawn
for these reaction products based upon elemental analyses, electrical conductance, magnetic moment and
spectral (UV‐vis, IR and 1H NMR) data. Studies were conducted to assess the growth‐inhibiting potential of
the complexes synthesized, and the ligands, against various fungal and bacterial strains.
Voltammetric Methods in Metallothionein Research
Authors: Šestáková Ivana , Navrátil Tomáš
Published: March 2007

The application of voltammetric methods using different rates of polarisation on HMDE reveal inert or labile behaviour of Cd‐ or Zn‐ complexes in the presence of excessive cadmium or zinc ions in solution. This
phenomenon was demonstrated first on the simplest phytochelatin – complex of peptide (γ‐Glu‐Cys)2Gly with cadmium, later on rabbit liver metallothioneins – Cd7MT in the presence of cadmium and Cd5Zn2MT in the presence of zinc. Voltammetric methods can distinguish between labile and inert complexes present simultaneously and therefore could elucidate their role in reactions of metal ion transfer.

Another method using different rates of polarisation – elimination voltammetry with linear scan – proved that S‐tetracoordinated complexes of Cd(II) or Zn(II) in the above‐mentioned metallothioneins on HMDE are
reduced in the adsorbed state. This implies the possibility of increasing the sensitivity of identification or
determination of the above complexes. On carbon composite electrode, similar behaviour of Cd‐complexes
as on HMDE was observed using differential pulse voltammetry.
Cobalt(II) Coordination Compounds of Ethyl 4‐Methyl‐5‐Imidazolecarboxylate: Chemical and Biochemical Characterization on Photosynthesis and Seed Germination
Authors: King-Díaz Beatriz , Montes-Ayala Josefina , Escartín-Guzmán Concepción , Castillo-Blum Silvia E. , Iglesias-Prieto Roberto , Lotina-Hennsen Blas , Barba-Behrens Norah
Published: March 2007

In this work we present the synthesis, structural and spectroscopic characterization of Co2+ coordination compounds with ethyl 4‐methyl‐5‐imidazolecarboxylate (emizco). The effects of emizco, the metal salts
CoCl2.6H2O, CoBr2, and their metal coordination compounds [Co(emizco)2Cl2], [Co(emizco)2Br2].H2O, were evaluated on photosynthesis in spinach
chloroplasts. Seed germination and seedling growth of the monocotyledonous species Lolium multiflorum and Triticum aestivum and the dicotyledonous species Trifolium alexandrinum and Physalis ixocarpa were also assayed under the effect of the compounds and salts. The results showed that cobalt(II) salts and their emizco coordination compounds inhibit photosynthetic electron flow and ATP‐synthesis, behaving as Hill reaction inhibitors. Coordination compounds are more potent inhibitors than the salts. It was found that the salts target is at the b6f level while the complexes targets are at QB(D1)‐protein and b6f level. The QB inhibition site was confirmed by variable chlorophyll a fluorescence yield. On the other hand, emizco inhibits seed germination, root and shoot development, in both weed and crop species. Cobalt(II) coordination compounds are the most effective photosynthesis inhibitors, but they are less potent than emizco in germination and seedling growth, while the metal salts are the least active of all.
Modulation of cancer cell survival pathways using multivalent liposomal therapeutic antibody constructs
Authors: Chiu Gigi N.C. , Edwards Lincoln A. , Kapanen Anita I. , Malinen Melina M. , Dragowska Wieslawa H. , Warburton Corinna , Chikh Ghania G. , Fang Karen Y.Y. , Tan Sophia , Sy Jonathan , Tucker Catherine , Waterhouse Dawn N. , Klasa Richard , Bally Marcel B.
Published: March 2007

Various methods have been explored to enhance antibody-based cancer therapy. The use of multivalent antibodies or fragments against tumor antigens has generated a great deal of interest, as various cellular signals, including induction of apoptosis, inhibition of cell growth/survival, or internalization of the surface molecules, can be triggered or enhanced on extensive cross-linking of the target/antibody complex by the multivalent form of the antibody. The goal of the studies reported here was to develop multivalent antibody constructs via grafting of antibody molecules onto liposome membranes to enhance antibody activity. Using trastuzumab and rituximab as examples, up to a 25-fold increase in the antibody potency in cell viability assay was observed when the antibodies were presented in the multivalent liposome formulation. Key cell survival signaling molecules, such as phosphorylated Akt and phosphorylated p65 nuclear factor-κB, were down-regulated on treatment with multivalent liposomal trastuzumab and liposomal rituximab, respectively. Potent in vivo antitumor activity was shown for liposomal trastuzumab. The data presented here showed the potential of liposome technology to enhance the therapeutic effect of antibodies via a mechanism that modulates cell survival through clustering of the target/antibody complex. [Mol Cancer Ther 2007;6(3):844–55]