bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of the very acid‐sensitive Fmoc‐Cys(Mmt)‐OH and its application in solid‐phase peptide synthesis
Authors: BARLOS KLEOMENIS , GATOS DIMITRIOS , HATZI OLGA , KOCH NICOLE , KOUTSOGIANNI SOFIA
Published: August 2010

S‐4‐methoxytrityl cysteine was synthesized and converted into the corresponding Fmoc‐Cys(Mmt)‐OH by its reaction with Fmoc‐OSu. As compared to the corresponding Fmoc‐Cys(Trt)‐OH, the S‐Mmt‐function was found to be considerably more acid labile. Quantitative S‐Mmt‐removal occurs selectively in the presence of groups of the tert butyl type and S‐Trt by treatment with 0.5–1.0% TFA. The new derivative was successfully utilized in the SPPS of Tyr1‐somatostatin on 2‐chlorotrityl resin. In this synthesis groups of the Trt‐type were exclusively used for amino acid side‐chain protection. Quantitative cleavage from the resin and complete deprotection was performed by treatment with 3% TFA in DCM–TES (95:5) for 30 min at RT. We observed no reduction of tryptophan under these conditions. © Munksgaard 1996.
Influence of zinc (II) binding on the structure of bovine α‐lactalbumin
Authors: TANAKA NAOKI , KUNUGI SHIGERU
Published: August 2010

The effect of Zn(II) binding on the structure of bovine α‐lactalbumin (LA) was investigated. α‐Lactalbumin, a regulatory subunit of lactose synthase, binds Ca(II) and Zn(II) at different sites in a mutually non‐exclusive manner. The structures of the metal‐depleted form of LA (apo‐LA) and Ca(II)‐bound LA (holo‐LA) have been well characterized. Here, the effect of Zn(II) binding on the structure of holo‐LA has been investigated by comparison with the structure of holo‐LA and apo‐LA using CD and NMR spectroscopy. The CD spectrum of Zn(II)‐holo‐LA was similar to that of holo‐LA, but the intensity of the negative peak in near‐UV region was decreased. Zn(II) binding to holo‐LA produced only small changes in NMR chemical shifts, but the integral volumes of the cross‐peaks of NOESY signals in cluster II, which is in the vicinity of Zn(II) binding site, were affected. Zn(II) binding induces a local structural change on the holo‐LA, but it does not induce a large backbone conformational change, © Munksgaard 1996.
Crystallographic characterization of geometry and conformation of TOAC, a nitroxide spin‐labelled Cα,α‐disubstituted glycine, in simple derivatives and model peptides *
Authors: FLIPPEN‐ANDERSON JUDITH L. , GEORGE CLIFFORD , VALLE GIANCARLO , VALENTE EZIO , BIANCO ALBERTO , FORMAGGIO FERNANDO , CRISMA MARCO , TONIOLO CLAUDIO
Published: August 2010

The molecular and crystal structures of one derivative and two oligopeptides of TOAC, a nitroxide spin‐labelled Cαα‐disubstituted glycine, have been determined by X‐ray diffraction. The derivative is the 5(4H)‐oxazolone from Piv‐TOAC‐OH; the oligopeptides are Z‐TOAC‐(L‐Ala)2‐NHtBu sesquihydrate and p BrBz‐TOAC‐(L‐Ala)2‐TOAC‐L‐Ala‐NHtBu hemihydrate. Incipient and fully developed right‐handed 310‐helical conformations are formed by both independent molecules in the asymmetric unit of the terminally blocked tripeptide amide and the terminally blocked pentapeptide amide, respectively. The average geometry and preferred conformation for the piperidine ring of the TOAC residues are also discussed in detail. © Munksgaard 1996.
Isolation and characterization of a trisulfide variant of recombinant human growth hormone formed during expression in Escherichia coli
Authors: ANDERSSON CLAES , EDLUND PER OLOF , GELLERFORS PÄR , HANSSON YNGVE , HOLMBERG ERLAND , HULT CARINA , JOHANSSON STIG , KÖRDEL JOHAN , LUNDIN RONNY , MENDEL‐HARTVIG IB , NORÉN BENGT , WEHLER THOMAS , WIDMALM GÖRAN , ÖHMAN JOHAN
Published: August 2010

A new variant of human growth hormone was recently found [Pavlu, B. & Gellerfors, P. (1993) Bioseparation 3, 257‐265]. We report here the identification and the structural determination of this variant. The variant, which is formed during the expression of human growth hormone in Escherichia coli, was found to be more hydrophobic than rhGH as judged by its prolonged elution time by hydrophobic interaction chromatography. The rhGH hydrophobic variant (rhGH‐HV) was isolated and subjected to trypsin digestion and RP‐HPLC analysis, resulting in an altered retention time of one single tryptic peptide as compared to the corresponding fragment of rhGH. This tryptic peptide constitutes the C‐terminus (aa 179‐191) of hGH and contains one of the two disulfide bridges in hGH, viz. CySl82‐Cys189.

Amino acid sequences and composition analyses of the tryptic peptide from rhGH‐HV (Tv18 + 19) and the corresponding tryptic peptide from rhGH (T18 + 19) were identical. Electrospray mass spectrometry (ES/MS) of Tv18 + 19 isolated from rhGH‐HV revealed a monoisotopic mass increase of 32.7, as compared to T18 + 19 from rhGH. A synthetic T18 + 19 peptide having a trisulfide bridge between Cys182 and Cys189 showed identical fragments in ES/MS compared to Tv18 + 19 isolated from rhGH‐HV, i.e. m/z 617.7 and 682.9. These fragments are formed through a unique cleavage in the trisulfide (Cysl82‐SSS‐Cys189) bridge not found in the corresponding T18 + 19 disulfide peptide. Furthermore, the synthetic Tv18 + 19 co‐eluted in RP‐HPLC with T18 + 19 isolated from rhGH‐HV. Two‐dimensional NMR spectroscopy of the synthetic T18 + 19 and Tv18 + 19 peptides were performed. Using these data all protons were assigned. The major chemical shift changes (δ§>0.05 ppm) observed were for the β‐protons of Cys182 and Cys189 in Tv18 + 19 as compared to T18 + 19. CD spectroscopy data were also in agreement with the above results. Based on these physico‐chemical data, rhGH‐HV has been structurally defined as a trisulfide variant of rhGH.

The receptor binding properties of rhGH‐HV was studied by a biosensor device, BIAcoreTM. The binding capacity of rhGH‐HV was similar to rhGH with a binding stoichiometry to the rhGHBP of 1:1.6 and 1:1.5, respectively, indicating that the trisulfide modification did not affect its receptor binding properties. © Munksgaard 1996.
Machine learning classification procedure for selecting SNPs in genomic selection: application to early mortality in broilers
Authors: Long N. , Gianola D. , Rosa G.J.M. , Weigel K.A. , Avendaño S.
Published: August 2010

SummaryGenome‐wide association studies using single nucleotide polymorphisms (SNPs) can identify genetic variants related to complex traits. Typically thousands of SNPs are genotyped, whereas the number of phenotypes for which there is genomic information may be smaller. When predicting phenotypes, options for statistical model building range from incorporating all possible markers into the specification to including only sets of relevant SNPs (features). In the latter case, an efficient method of selecting influential features is required. A two‐step feature selection method for binary traits was developed, which consisted of filtering (using information gain), and wrapping (using naïve Bayesian classification). The filter reduces the large number of SNPs to a much smaller size, to facilitate the wrapper step. As the procedure is tailored for discrete outcomes, an approach based on discretization of phenotypic values was developed, to enable feature selection in a classification framework. The method was applied to chick mortality rates (0–14 days of age) on progeny from 201 sires in a commercial broiler line, with the goal of identifying SNPs (over 5000) related to progeny mortality. To mimic a case–control study, sires were clustered into two groups, low and high, according to two arbitrarily chosen mortality rate cut points. By varying these thresholds, 11 different ‘case–control’ samples were formed, and the SNP selection procedure was applied to each sample. To compare the 11 sets of chosen SNPs, predicted residual sum of squares (PRESS) from a linear model was used. The two‐step method improved naïve Bayesian classification accuracy over the case without feature selection (from around 50 to above 90% without and with feature selection in each case–control sample). The best case–control group (63 sires above or below the thresholds) had the smallest PRESS statistic among groups with model p‐values below 0.003. The 17 SNPs selected using this group accounted for 31% of the variation in raw mortality rates between sire families.
Somitogenesis as a model to study the formation of morphological boundaries and cell epithelialization
Authors: Takahashi Yoshiko , Sato Yuki
Published: August 2010

The formation of morphological boundaries between developing tissues is an integral mechanism for generating body forms and functions. For the molecular and cellular studies of how such morphological boundaries form, somitogenesis serves as a particularly good model. When an intersomitic boundary forms in the anterior end of the presomitic mesoderm, cells undergo dynamic behaviors including a separation of tissues and changes in cell shape from mesenchymal to epithelial. Moreover, these events occur repeatedly and periodically. We here overview the inductive events that have recently been shown to play important roles in the formation of the intersomitic fissures. We then discuss molecular mechanisms underlying these inductive actions, and also discuss how the fissure formation is interpreted by the subsequent morphogenesis, including cell epithelialization and the acquisition of anterior–posterior identities in the newly formed somite. Thus, somitogenesis provides a unique model to understand how sequentially occurring processes of morphogenesis are coordinated in a 3‐D environment.
Clinicopathological study of lymphocyte attachment to endothelial cells (endothelialitis) in various liver diseases
Authors: Nonomura Akitaka , Mizukami Yuji , Matsubara Fujitsugu , Kobayashi Kenichi
Published: August 2010

ABSTRACT— An attachment of lymphocytes to the vascular wall, a feature called “endothelialitis” (ETL) or “endotheliitis“, was investigated in various liver biopsies, including acute hepatitis (AH), hepatic infectious mononucleosis (IM), drug‐induced hepatitis, alcoholic hepatitis and fibrosis, chronic persistent hepatitis (CPH), chronic active hepatitis (CAH), liver cirrhosis (LC), primary biliary cirrhosis (PBC), nonspecific reactive hepatitis (NSRH), and cases with a variety of diseases having almost normal liver histology as control material. Although ETL has been considered to be nearly pathognomic of graft‐versus‐host disease (GVHD) and acute transplant rejection, ETL was found in both portal and central veins with a variable incidence, not only in all categories of liver diseases, but also in the control group. The incidence of central vein ETL was significantly higher in AH, CAH, PBC, IM, alcoholic fibrosis, and NSRH than that of the control group, and that of portal vein ETL was significantly higher in AH, CPH, CAH, LC, PBC, IM, and alcoholic fibrosis. Even under the light microscope, lymphocytes attached to the endothelial cells had irregular cytoplasmic processes making contact with endothelial cells. Also lymphocytes located beneath the endothelial lining were frequently found. When ETL‐positive and ‐negative cases in the same category were compared, the levels of serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) were usually higher in the ETL‐positive group, and statistically significant differences were observed in CPH, CAH, LC, PBC and NSRH. In chronic hepatitis, the occurrence of portal vein ETL paralleled the histologic activity of portal inflammation, whereas central vein endothelialitis was associated with active parenchymal inflammation such as sinusoidal lymphocyte infiltration and spotty hepatocyte necrosis, indicating that ETL may be a phenomenon more frequently associated with active hepatic inflammation. Immunohistochemical observations revealed that about 70% of lymphocytes attached to the endothelial cells were T cells, while about 10% were B cells. These data indicate that ETL in the liver is not specifically pathognomonic for GVHD and rejection of liver transplants, and is universally found in a variety of liver diseases with a varying incidence and activity, related to the activity of hepatic inflammation, portal vein ETL occurring in relation to active portal inflammation and central vein ETL to parenchymal inflammation. Thus ETL is considered to be an intimate T lymphocyte‐endothelial cell interaction universally associated with active hepatic inflammation; it may be an important phenomenon leading to accumulation of cellular exudates and their reaction at the site of antigen in the tissue.
Tetrahydro‐β‐carbolines and Corresponding Tryptamines:In VitroInhibition of Serotonin, Dopamine and Noradrenaline Uptake in Rat Brain Synaptosomes
Authors: Komulainen Hannu , Tuomisto Jouko , Airaksinen Mauno M. , Kari Ilkka , Peura Pekka , Pollari Liisa
Published: August 2010

AbstractThe structure activity relationships of tryptolines and some other β‐carbolines and tryptamines as inhibitors of serotonin (5‐HT), dopamine (DA) and noradrenaline (NA) uptake were studied in rat brain synaptosomes. All β‐carbolines inhibited to higher degree the uptake of 5‐HT than that of DA or NA (IC50's 5–100 times lower). The most potent tryptoline derivative was 6‐hydroxy‐tetrahydro‐β‐carboline (5‐hydroxytryptoline, 6‐OH‐THBC) with an IC50 of 5.0× 10‐7M at a 5‐HT concentration of 10‐7M. 6‐Methoxy‐tetrahydro‐β‐carboline (5‐methoxytryptoline) was slightly weaker; the inhibition of 5‐HT uptake and DA uptake being competitive. Also tetrahydro‐β‐carboline (tryptoline) was more potent than its 1‐methylderivative, tetrahydroharmane (methtryptoline) or norharmane (β‐carboline). All of them were, however, weaker inhibitors of 5‐HT uptake than the freely rotating indoleamines N‐methyl‐tryptamine (N‐Me‐T) or 5‐HT itself. N‐Me‐T and 5‐HT were also more potent inhibitors of DA and NA uptake than most of the β‐carbolines, DA uptake, however, was inhibited better by 6‐OH‐THBC than by 5‐HT or N‐Me‐T. Tetrahydro‐β‐carbolines may inhibit 5‐HT uptake alsoin vivobut it is unlikely that catecholamine uptake is affected.
Numerical Simulation of Random Wave Forces Near the Free
Surface
Authors: Isaacson M. , Subbiah K.
Published: August 2010

The present paper describes the numerical simulation of random wave forces acting on a section of fixed slender vertical cylinder near the free surface, taking account of the intermittency of submergence. Time histories of water particle kinematics corresponding to a specified wave spectrum are generated using linear numerical transforms and corresponding force time histories at different sections are computed using the Morison equation. Analytical predictions of various statistical properties of water particle kinematics and forces for the intermittent flow are compared with results of the numerical simulations. These include the probability density of particle kinematics, the spectral density of the force, the probability density of force maxima, and the mean and standard deviation of the force maxima. In general, the agreement is found to be quite satisfactory. The effects of simulation time and random phases on the mean and standard deviation of intermittent force maxima are also investigated.
A Comparative Overview of Marine Risers and Heat Exchanger Tube
Banks
Authors: Zdravkovich M. M.
Published: August 2010

This is neither an original paper nor a review, but a comparative overview of two seemingly unrelated engineering fields. There are some similarities and strong dissimilarities between multipipe risers and tube arrays employed in heat exchangers. For example, square arrays are used in both, whereas “satellite” clusters cannot be found in heat exchangers. The extensive research on flow-induced vibrations in heat exchanger arrays reveals several mechanisms of excitation and sustenance of tube vibration. Some of the mechanisms identified for tube arrays may be relevant for marine risers. The main object of this comparative overview is to compile and discuss heat exchanger data which may be applicable to marine risers. Design guidelines are specified for satellite clusters.
Dynamic Ride-Up and Crushing of Short Ice Ridges on Conical
Structures
Authors: Nordgren R. P. , Winkler M. M.
Published: August 2010

An analysis is presented for the plane motion of an ice ridge being pushed up a faceted conical structure by a floe moving at constant velocity. The effect of crushing of the ridge against the rigid structure is included by means of an idealized crushing model. The effect of changing buoyancy is included in the analysis. The plane, rigid-body equations of motion are solved numerically for finite displacement and rotation of the ridge. A quasi-static flexural model is used to determine conditions for failure of the ridge in lengthwise bending. Numerical results for a typical problem are presented and discussed. The impulsive-type contact force at initial impact depends strongly on impact velocity and ice-crushing strength. However, the maximum force on the structure usually occurs later after the ridge has ridden up on the structure. This force is nearly independent of velocity. For realistic crushing strengths, the maximum force is significantly lower than in our previous static analysis of ridge ride-up without crushing. With consideration of lengthwise flexural failure, the dynamic ride-up model is applied to the development of design loads for a 40-deg conical structure.
Iceberg/Seabed Interaction Events Observed During the DIGS
Experiment
Authors: Lever J. H. , Bass D. W. , Lewis C. F. M. , Klein K. , Diemand D. , Dyke M.
Published: August 2010

The Dynamics of Iceberg Grounding and Scouring (DIGS) experiment was conducted in the Labrador Sea during August 1985. The objectives of the experiment were to obtain full-scale data sets documenting iceberg/seabed interactions, and to obtain by direct observation new information regarding the processes of iceberg scour formation and degradation. Utilizing a vessel and a helicopter, measurements were made of icebergs’ above and below-water shapes, plus local winds, waves, currents and tides. Special self-contained motion monitoring packages were deployed by helicopter on icebergs thought to be good grounding candidates. Seabed observations were made directly using the submersible Pisces IV, and extensive side-scan sonar data were collected. This paper describes two dynamic iceberg/seabed interaction events documented during DIGS: the roll/pitting behavior of the 1.2-million-ton domed iceberg “Bertha,” and the split/grounding behavior of the 7.7-million-ton tabular iceberg “Gladys.” This latter event is particularly interesting due to its very energetic nature, and the fact that it represents the only full-scale observation of any iceberg impact with sufficient documentation to yield estimates of the interaction forces. Subsequent to the experiment, the recorded above and below-water shapes were used to obtain hydrostatic stability maps for these icebergs. A time stepping procedure was also developed to re-create these two dynamic events, and comparisons between the observed and simulated motions are provided in this paper.
Parametric Studies of Guyed Tower Platforms
Authors: Owen D. G. , Shi Y. J.
Published: August 2010

A parametric study presented in this paper has investigated the interactions between structural properties and dynamic response for a guyed tower platform. The finite element method is introduced to simulate the guyed tower motion response under various environmental conditions. The structural parameters which could significantly influence the motion response are the objectives to be investigated. The topside weight, guyline restraints and P-Δ or B-Δ effects are the vital aspects. A number of model tests were conducted to support and verify the theoretical predictions. The analysis concluded that the guyline stiffness is the most important characteristic which determines the guyed tower motion response.
Damage Tolerance of Composite Structures: The Role of Interlaminar Fracture Mechanics
Authors: Gillespie J. W.
Published: August 2010

Layered fiber-reinforced composite structures are susceptible to crack initiation and growth in the resin-rich layer between plies. Delamination represents one of the most prevalent life-limiting failure modes in laminated composite structures. Interlaminar fracture mechanics represents one approach to assess the damage tolerance of composite structures. This paper is organized into two major sections. The first sections introduces interlaminar fracture mechanics and test methods that have been developed to characterize the Mode I, II and III interlaminar fracture toughness of composite laminates. In the second section, the role of interlaminar fracture mechanics in assessing damage tolerance of composite structures is defined through the following case studies: residual compression after impact strength, instability related delamination growth in compressively loaded laminates and delamination growth in composite laminates with discontinuous internal plies.
Triaxial Testing of Freshwater Ice at Low Confining Pressures
Authors: Nadreau J. P. , Nawwar A. M. , Wang Y. S.
Published: August 2010

Tests have been conducted on freshwater columnar ice samples to determine the uniaxial and triaxial compressive strength of the ice. Four parameters were varied. The confining pressure was increased up to 2.85 MPa (400 psi) in steps of 0.7 MPa (100 psi). The strain rate was varied in order to obtain the ductile to brittle transition peak. Temperature was kept mainly at −2°, with two series at −10°C and −20°C, and samples were machined with axes parallel, perpendicular or at a 45-deg angle to the direction of ice growth. The results are presented within their original context, but analyzed with reference to recent studies conducted on the multiaxial behavior of ice.
Elasticity of the Porcine Lens Capsule as Measured by Osmotic Swelling
Authors: Powell Tracy A. , Amini Rouzbeh , Oltean Alina , Barnett Vincent A. , Dorfman Kevin D. , Segal Yoav , Barocas Victor H.
Published: August 2010

As an alternative to purely mechanical methods, optical tracking of passive osmotic swelling was used to assess mechanical properties of the porcine lens capsule. A simple model was developed accounting for the permeability of the lens fiber cells and capsule to water, the concentration of fixed charges in the fiber cells, and the capsule’s resistance to the swelling of fiber cells. Fitting the model solution to experimental data provided an estimate of the elastic modulus of the lens capsule under the assumption of linear isotropic elasticity. The calculated elastic modulus at a fixed charge density of 20 mol m−3 was 2.0±0.5 MPa (mean±95% confidence interval; n=15) for 0.1% saline solution, 0.64±0.3 MPa(n=10) for 0.2% saline solution, and 0.28±0.5 MPa(n=6) for 0.5% saline solution. These values are comparable to previously reported moduli of elasticity for the porcine lens capsule at small strains (<10%), and the slight increase with hypotonicity is consistent with the nonlinear mechanical behavior of the lens capsule. Although limited by being a single measurement on a heterogeneous tissue, osmotic swelling provides a quantitative assessment of the stiffness of the lens capsule without requiring dissection or manipulation of the lens. Thus, the new method could be useful for small animal models.
A Biomechanical Investigation of Ankle Injury Under Excessive External Foot Rotation in the Human Cadaver
Authors: Wei Feng , Villwock Mark R. , Meyer Eric G. , Powell John W. , Haut Roger C.
Published: August 2010

Numerous studies on the mechanisms of ankle injury deal with injuries to the syndesmosis and anterior ligamentous structures but a previous sectioning study also describes the important role of the posterior talofibular ligament (PTaFL) in the ankle’s resistance to external rotation of the foot. It was hypothesized that failure level external rotation of the foot would lead to injury of the PTaFL. Ten ankles were tested by externally rotating the foot until gross injury. Two different frequencies of rotation were used in this study, 0.5 Hz and 2 Hz. The mean failure torque of the ankles was 69.5±11.7 Nm with a mean failure angle of 40.7±7.3°. No effects of rotation frequency or flexion angle were noted. The most commonly injured structure was the PTaFL. Visible damage to the syndesmosis only occurred in combination with fibular fracture in these experiments. The constraint of the subtalar joint in the current study may have affected the mechanics of the foot and led to the resultant strain in the PTaFL. In the real world, talus rotations may be affected by athletic footwear that may influence the location and potential for an ankle injury under external rotation of the foot.
Proof of principle for inversion of vector sensor array data
Authors: Koch Robert A.
Published: August 2010

Acoustic data collected from a 22 m long horizontal line array with elements comprised of omni-directional hydrophone sensors co-located with acceleration vector sensor triplets are analyzed for seabed geo-acoustic information. Broadband and continuous wave tone data were recorded from the passage of a surface vessel source, the R/V Montague, in an August 2006 experiment conducted in Monterey Bay. The water depth at the array and along the source track was approximately 85 m. Simultaneous inversions for source track and geo-acoustic parameters were performed with 18 tones from the 62–415 Hz tone data for source ranges 0.5–2.0 km. The efficacy of inversions with vector sensor data is demonstrated by the fact that data from vector sensor acceleration components parallel to the array line of bearing produced inversion solutions approximately identical to the solutions obtained from the inversion of data for the same tones from the hydrophone array components. In addition the source spectra derived from these inversions are in nominal agreement with the source spectra obtained from an independent measurement.
A re-expansion method for determining the acoustical impedance and the scattering matrix for the waveguide discontinuity problem
Authors: Homentcovschi Dorel , Miles Ronald N.
Published: August 2010

The paper gives a new method for analyzing planar discontinuities in rectangular waveguides. The method consists of a re-expansion of the normal modes in the two ducts at the junction plane into a system of functions accounting for the velocity singularities at the corner points. As the new expansion has an exponential convergence, only a few terms have to be considered for obtaining the solution of most practical problems. To see how the method works some closed form solutions, obtained by the conformal mapping method, are used to discuss the convergence of the re-expanded series when the number of retained terms increases. The equivalent impedance accounting for nonplanar waves into a plane-wave analysis is determined. Finally, the paper yields the scattering matrix which describes the coupling of arbitrary modes at each side of the discontinuity valid in the case of many propagating modes in both parts of the duct.
The just noticeable difference of center time and clarity index in large reverberant spaces
Authors: Martellotta F.
Published: August 2010

Just noticeable difference (JND) values are available for most acoustical parameters currently used in practice. However, they have been determined with reference to conditions typically encountered in concert halls and in rooms for speech, covering a range of reverberation times (T) spanning from 0.5 s to 2 s. When reverberation gets longer, the relationship between measured parameters describing acoustic clarity may change significantly and subjective perception might also be different. The proposed research investigates the influence of reverberation time on JND for clarity measures taking into account three reference cases having T values varying from 2 s to 6 s. Measured B-format impulse responses were properly modified to introduce the desired changes and then auralized with two music motifs for presentation on a 4-channel playback system. Listening tests based on paired comparisons were carried out to determine subjective limens. The results proved to be independent of music motifs and showed that JND in the clarity index is almost independent of T, while JND in the center time is significantly related to T and can be assumed as the 8.5% of the reference TS value.
Intraglottal pressures in a three-dimensional model with a non-rectangular glottal shape
Authors: Scherer Ronald C. , Torkaman Saeed , Kucinschi Bogdan R. , Afjeh Abdollah A.
Published: August 2010

This study used a symmetric, three-dimensional, physical model of the larynx called M6 in which the transverse plane of the glottis is formed by sinusoidal arcs for each medial vocal fold surface, creating a maximum glottal width of 0.16 cm at the location of the minimal glottal area. Three glottal angles were studied: convergent 10°, uniform (0°), and divergent 10°. Fourteen pressure taps were incorporated in the upstream-downstream direction on the vocal fold surface at three coronal locations, at the one-fourth, one-half, and three-fourths distances in the anterior-posterior direction of the glottis. The computational software FLUENT was used to compare and augment the data for these cases. Near the glottal entrance, the pressures were similar across the three locations for the uniform case; however, for the convergent case the middle pressure distribution was lower by 4% of the transglottal pressure, and lower by about 2% for the divergent case. Also, there were significant secondary velocities toward the center from both the anterior commissure and vocal process regions (of as much as approximately 10% of the axial velocities). Thus, the three dimensionality created relatively small pressure gradients and significant secondary velocities anteriorly-posteriorly within the glottis.
Locating arbitrarily time-dependent sound sources in three dimensional space in real time
Authors: Wu Sean F. , Zhu Na
Published: August 2010

This paper presents a method for locating arbitrarily time-dependent acoustic sources in a free field in real time by using only four microphones. This method is capable of handling a wide variety of acoustic signals, including broadband, narrowband, impulsive, and continuous sound over the entire audible frequency range, produced by multiple sources in three dimensional (3D) space. Locations of acoustic sources are indicated by the Cartesian coordinates. The underlying principle of this method is a hybrid approach that consists of modeling of acoustic radiation from a point source in a free field, triangulation, and de-noising to enhance the signal to noise ratio (SNR). Numerical simulations are conducted to study the impacts of SNR, microphone spacing, source distance and frequency on spatial resolution and accuracy of source localizations. Based on these results, a simple device that consists of four microphones mounted on three mutually orthogonal axes at an optimal distance, a four-channel signal conditioner, and a camera is fabricated. Experiments are conducted in different environments to assess its effectiveness in locating sources that produce arbitrarily time-dependent acoustic signals, regardless whether a sound source is stationary or moves in space, even toward behind measurement microphones. Practical limitations on this method are discussed.
Subjective quantification of earplug occlusion effect using external acoustical excitation of the mouth cavity
Authors: Le Cocq Cécile , Laville Frédéric , Gargour Christian
Published: August 2010

Occlusion of the ear canal by hearing aids or hearing protectors often results in an occlusion effect, which creates a discomfort to wearers in that it changes their perception of their own voice. As no account was found in the literature on the quantification of this subjective voice occlusion effect, an experimental method is proposed based on the use of an artificial sound source emitting within the subject’s mouth to replace his own voice. A block diagram is constructed to identify the different internal sound path components involved in the perception of one’s own voice and is used to show that the subjective voice occlusion effect is the weighted energy summation of two components. The first component, the voice air and body conduction occlusion effect for which data is obtained from the experiments reported in the present paper, constitute the lower limit of the subjective voice occlusion effect. The second component, the voice body conduction occlusion effect for which data is available in the literature, constitutes the upper limit. From these limits, order of magnitudes for subjective voice occlusion effect intervals are estimated to be [+5+20] dB below 2000 Hz and [−10+5] dB above 2000 Hz.
Acoustic contributions of a sound absorbing blanket placed in a double panel structure: Absorption versus transmission
Authors: Doutres Olivier , Atalla Noureddine
Published: August 2010

The objective of this paper is to propose a simple tool to estimate the absorption vs. transmission loss contributions of a multilayered blanket unbounded in a double panel structure and thus guide its optimization. The normal incidence airborne sound transmission loss of the double panel structure, without structure-borne connections, is written in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The method is applied to four different blankets frequently used in automotive and aeronautic applications: a non-symmetric multilayer made of a screen in sandwich between two porous layers and three symmetric porous layers having different pore geometries. It is shown that the absorption behavior of the blanket controls the acoustic behavior of the treatment at low and medium frequencies and its transmission loss at high frequencies. Acoustic treatment having poor sound absorption behavior can affect the performance of the double panel structure.
Absolute pitch correlates with high performance on musical dictation
Authors: Dooley Kevin , Deutsch Diana
Published: August 2010

Absolute pitch (AP)—the ability to name a musical note in the absence of a reference note—is a rare ability whose relevance to musical proficiency has so far been unclear. Sixty trained musicians—thirty who self-reported AP and thirty with equivalent age of onset and duration of musical training—were administered a test for AP and also a musical dictation test not requiring AP. Performance on both types of test were highly correlated (r=.81, p<.001). When subjects were divided into three groups based on their performance on the AP test, highly significant differences between the groups emerged. Those who clearly possessed AP showed remarkably high performance on the musical dictation test, the scores of those without AP varied widely, and the performance of the intermediate group of borderline AP possessors fell between that of clear AP possessors and clear nonpossessors. The findings support the hypothesis that AP is associated with proficiency in performing other musical tasks, and run counter to the claim that it confers a disadvantage in the processing of relative pitch.
Design and analysis of a recoil-type vibrotactile transducer
Authors: Yao Hsin-Yun , Hayward Vincent
Published: August 2010

This article describes the design of a high-bandwidth, iron-less, recoil-based electromagnetic vibrotactile actuator. Its working principle, the theoretical analysis, the method used to determine its transfer function, its scaling properties and its design constraints are discussed along with its fabrication and possible improvements.
Hearing one’s own voice during phoneme vocalization—Transmission by air and bone conduction
Authors: Reinfeldt Sabine , Östli Per , Håkansson Bo , Stenfelt Stefan
Published: August 2010

The relationship between the bone conduction (BC) part and the air conduction (AC) part of one’s own voice has previously not been well determined. This relation is important for hearing impaired subjects as a hearing aid affects these two parts differently and thereby changes the perception of one’s own voice. A large ear-muff that minimized the occlusion effect while still attenuating AC sound was designed. During vocalization and wearing the ear muff the ear-canal sound pressure could be related to the BC component of a person’s own voice while the AC component was derived from the sound pressure at the entrance of an open ear-canal. The BC relative to AC sensitivity of one’s own voice was defined as the ratio between these two components related to the ear-canal sound pressure at hearing thresholds for BC and AC stimulation. The results of ten phonemes showed that the BC part of one’s own voice dominated at frequencies between 1 and 2 kHz for most of the phonemes. The different phonemes gave slightly different results caused by differences during vocalization. However, similarities were seen for phonemes with comparable vocalization.
Speech-on-speech masking with variable access to the linguistic content of the masker speech
Authors: Calandruccio Lauren , Dhar Sumitrajit , Bradlow Ann R.
Published: August 2010

It has been reported that listeners can benefit from a release in masking when the masker speech is spoken in a language that differs from the target speech compared to when the target and masker speech are spoken in the same language [Freyman, R. L. et al. (1999). J. Acoust. Soc. Am. 106, 3578–3588; Van Engen, K., and Bradlow, A. (2007), J. Acoust. Soc. Am. 121, 519–526]. It is unclear whether listeners benefit from this release in masking due to the lack of linguistic interference of the masker speech, from acoustic and phonetic differences between the target and masker languages, or a combination of these differences. In the following series of experiments, listeners’ sentence recognition was evaluated using speech and noise maskers that varied in the amount of linguistic content, including native-English, Mandarin-accented English, and Mandarin speech. Results from three experiments indicated that the majority of differences observed between the linguistic maskers could be explained by spectral differences between the masker conditions. However, when the recognition task increased in difficulty, i.e., at a more challenging signal-to-noise ratio, a greater decrease in performance was observed for the maskers with more linguistically relevant information than what could be explained by spectral differences alone.
Geographic variations in the whistles of bottlenose dolphins (Tursiops aduncus) along the east and west coasts of Australia
Authors: Hawkins E. R.
Published: August 2010

Macrogeographic variations in the structure and repertoire of whistles from four geographically separated bottlenose dolphin (Tursiops aduncus) populations from the east and west coasts of Australia were investigated. Microgeographic variations were examined from two adjacent social groups from the same east coast population. Whistles were divided into five different tonal classes; sine, rise, down-sweep, flat and concave. The acoustic parameters of whistles; start, end, low, high and carrier frequencies and the number of inflection points and harmonics were measured and compared. These features were used to identify and define distinct whistle types. Differences in acoustic parameters of whistles between populations varied with the tonal class and the acoustic parameter being tested and were likely to be driven by localized environmental conditions. There were few differences in the acoustic parameters of whistles between social groups which was likely a result of vocal learning and mimicry from intermixing of individuals. There were small percentages of distinct whistle types that were shared between the both intermixing social groups and geographically separated populations, however, the majority of the whistle repertoires were unique. The development of the unique whistle repertoires may be primarily driven by the complex social organization of the bottlenose dolphin.
Estimation of modal group velocities with a single receiver for geoacoustic inversion in shallow water
Authors: Bonnel Julien , Nicolas Barbara , Mars Jérome I. , Walker Shane C.
Published: August 2010

Due to the expense associated with at-sea sensor deployments, a challenge in underwater acoustics has been to develop methods requiring a minimal number of sensors. This paper introduces an adaptive time-frequency signal processing method designed for application to a single source-receiver sensor pair. The method involves the application of conjugate time-frequency warping transforms to improve the SNR and resolution of the time-frequency distribution (TFD) of the measured field. Such refined knowledge of the TFD facilitates efforts to extract tomographic information about the propagation medium. Here the method is applied to the case of modal propagation in a shallow ocean range independent environment to extract a refined TFD. Given knowledge of the source-receiver separation, the refined TFD is used to extract the frequency dependent group velocities of the individual modal components. The extracted group velocities are then incorporated into a computationally light tomographic inversion method. Simulated and experimental results are discussed.
Ultrasonic output from the excised rat larynx
Authors: Johnson Aaron M. , Ciucci Michelle R. , Russell John A. , Hammer Michael J. , Connor Nadine P.
Published: August 2010

The source of ultrasonic vocalizations (USVs) produced by rats is thought to be within the larynx. The purpose of this investigation was to determine if the rat larynx is capable of producing ultrasounds with the full range of frequencies reported in vivo. Acoustic output of excised rat larynges with and without vocal fold constriction was measured. At biologically-reasonable airflow rates and pressures, only larynges with a constriction produced the full range of ultrasounds reported in vivo, providing support for the hypothesis that a constriction within the larynx is likely the source of rat USVs.
Perceptual assimilation of American English vowels by inexperienced Russian listeners
Authors: Gilichinskaya Yana D. , Strange Winifred
Published: August 2010

In a perceptual assimilation task, 16 Russian speakers categorized American English (AE) vowels [iː, ɪ, ɛ, aeː, ɑː, ʌ, ʊ, uː] in /Vpə/ disyllables into Russian (RU) response categories and rated their perceived goodness on a 9-point Likert scale. Cross-language discriminant analysis established acoustic similarities to Russian vowels. For all but AE [ε], acoustic similarity predicted modal assimilation responses. Russian listeners consistently assimilated AE point vowels to their Russian counterparts, whereas assimilation of the remaining vowels was less consistent. These acoustic and perceptual similarity patterns provide a baseline for future studies of AE vowel discrimination by Russian learners of English.
Axenfeld-Rieger Syndrome Associated with Congenital Glaucoma and Cytochrome P4501B1 Gene Mutations
Authors: Tanwar Mukesh , Dada Tanuj , Dada Rima
Published: August 2010

Developmental anomalies of the ocular anterior chamber angle may lead to an incomplete development of the structures that form the conventional aqueous outflow pathway. Thus, disorders that present with such dysfunction tend to be associated with glaucoma. Among them, Axenfeld-Rieger (ARS) malformation is a rare clinical entity with an estimated prevalence of one in every 200,000 individuals. The changes in eye morphogenesis in ARS are highly penetrant and are associated with 50% risk of development of glaucoma. Mutations in the cytochrome P4501B1 (CYP1B1) gene have been reported to be associated with primary congenital glaucoma and other forms of glaucoma and mutations in pituitary homeobox 2 (PITX2) gene have been identified in ARS in various studies. This case was negative forPITX2mutations and compound heterozygote forCYP1B1mutations. Clinical manifestations of this patient include bilateral elevated intraocular pressure (>40 mmHg) with increased corneal diameter (>14 mm) and corneal opacity. Patient also had iridocorneal adhesions, anteriorly displaced Schwalbe line, anterior insertion of iris, broad nasal bridge and protruding umbilicus. This is the first study from north India reportingCYP1B1mutations in Axenfeld-Rieger syndrome with bilateral buphthalmos and early onset glaucoma. Result of this study supports the role ofCYP1B1as a causative gene in ASD disorders and its role in oculogenesis.
Symplectic Integrators to Stochastic Hamiltonian Dynamical Systems Derived from Composition Methods
Authors: Misawa Tetsuya
Published: August 2010

“Symplectic” schemes for stochastic Hamiltonian dynamical systems are formulated through “composition methods (or operator splitting methods)” proposed by Misawa (2001). In the proposed methods, a symplectic map, which is given by the solution of a stochastic Hamiltonian system, is approximated by composition of the stochastic flows derived from simpler Hamiltonian vector fields. The global error orders of the numerical schemes derived from the stochastic composition methods are provided. To examine the superiority of the new schemes, some illustrative numerical simulations on the basis of the proposed schemes are carried out for a stochastic harmonic oscillator system.
Formulation of 2D Graphene Deformation Based on Chiral‐Tube Base Vectors
Authors: Sun Bohua
Published: August 2010

The intrinsic feature of graphene honeycomb lattice is defined by its chiral index (n, m), which can be taken into account when using molecular dynamics. However, how to introduce the index into the continuum model of graphene is still an open problem. The present manuscript adopts the continuum shell model with single director to describe the mechanical behaviors of graphene. In order to consider the intrinsic features of the graphene honeycomb lattice—chiral index (n, m), the chiral‐tube vectors of graphene in real space have been used for construction of reference unit base vectors of the shell model; therefore, the formulations will contain the chiral index automatically, or in an explicit form in physical components. The results are quite useful for future studies of graphene mechanics.
On the Operator ⨁ Bk Related to Bessel Heat Equation
Authors: Satsanit Wanchak
Published: August 2010

We study the equation with the initial condition u(x, 0) = f(x) for The operator is the operator iterated k‐times and is defined by , where p + q = n is the dimension of the , , 2vi = 2αi + 1, αi > −1/2, i = 1,2, 3, …, n, and k is a nonnegative integer, u(x, t) is an unknown function for , f(x) is a given generalized function, and c is a positive constant. We obtain the solution of such equation, which is related to the spectrum and the kernel, which is so called Bessel heat kernel. Moreover, such Bessel heat kernel has interesting properties and also related to the kernel of an extension of the heat equation.
Hypermethylation of SOX2 Promoter in Endometrial Carcinogenesis
Authors: Wong Oscar Gee-Wan , Huo Zhen , Siu Michelle Kwan-Yee , Zhang HuiJuan , Jiang LiLi , Wong Ester Shuk-Ying , Cheung Annie Nga-Yin
Published: August 2010

This paper aimed at investigating the expression and methylation profiles of SOX2, a gene coding for the stem cell‐related transcription factor SOX2, in endometrial carcinomas. By methylation‐specific polymerase chain reaction (MS‐PCR), the methylation status of SOX2 promoter region in 72 endometrial carcinomas and 12 normal endometrial samples was examined. Methylated allele was found in 37.5% (27/72) of endometrial carcinomas but only in 8.3% (1/12) of normal endometrial, significantly more frequent in cancers (P = .0472). SOX2 mRNA level was significantly reduced in endometrial carcinoma compared with nonneoplastic endometrium (P = .045). A significant correlation between SOX2 mRNA expression and hypermethylation of SOX2 was found (P = .024). Hypermethylation of SOX2 tended to be more frequently found in type II serous or clear cell adenocarcinoma. SOX2 methylation was also significantly correlated with shorter survival of patients (P = .046). In conclusion, epigenetic mechanisms may play a crucial role on the transcriptional regulation of SOX2 and loss of SOX2 expression may be related to endometrial carcinogenesis.