bluuebunny/crossref_metadata_2025 huggingface dataset:
Relaxation of sound fields in rooms of diffusely reflecting boundaries and its application in acoustical radiosity simulation
Authors: Zhang Honghu
Published: March 2006

The acoustical radiosity method is a computationally expensive acoustical simulation algorithm that assumes an enclosure with ideal diffuse reflecting boundaries. Miles observed that for such an enclosure, the sound energy decay of every point on the boundaries will gradually converge to exponential manner with a uniform decay rate. Therefore, the ratio of radiosity between every pair of points on the boundaries will converge to a constant, and the radiosity across the boundaries will approach a fixed distribution during the sound decay process, where radiosity is defined as the acoustic power per unit area leaving (or being received by) a point on a boundary. We call this phenomenon the “relaxation” of the sound field. In this paper, we study the relaxation in rooms of different shapes with different boundary absorptions. Criteria based on the relaxation of the sound field are proposed to terminate the costly and unnecessary radiosity computation in the later phase, which can then be replaced by a fast regression step to speed up the acoustical radiosity simulation.
Age-related differences in identification and discrimination of temporal cues in speech segments
Authors: Gordon-Salant Sandra , Yeni-Komshian Grace H. , Fitzgibbons Peter J. , Barrett Jessica
Published: March 2006

This study investigated age-related differences in sensitivity to temporal cues in modified natural speech sounds. Listeners included young noise-masked subjects, elderly normal-hearing subjects, and elderly hearing-impaired subjects. Four speech continua were presented to listeners, with stimuli from each continuum varying in a single temporal dimension. The acoustic cues varied in separate continua were voice-onset time, vowel duration, silence duration, and transition duration. In separate conditions, the listeners identified the word stimuli, discriminated two stimuli in a same-different paradigm, and discriminated two stimuli in a 3-interval, 2-alternative forced-choice procedure. Results showed age-related differences in the identification function crossover points for the continua that varied in silence duration and transition duration. All listeners demonstrated shorter difference limens (DLs) for the three-interval paradigm than the two-interval paradigm, with older hearing-impaired listeners showing larger DLs than the other listener groups for the silence duration cue. The findings support the general hypothesis that aging can influence the processing of specific temporal cues that are related to consonant manner distinctions.
Perceptual invariance of coarticulated vowels over variations in speaking rate
Authors: Stack Janet W. , Strange Winifred , Jenkins James J. , Clarke William D. , Trent Sonja A.
Published: March 2006

This study examined the perception and acoustics of a large corpus of vowels spoken in consonant-vowel-consonant syllables produced in citation-form (lists) and spoken in sentences at normal and rapid rates by a female adult. Listeners correctly categorized the speaking rate of sentence materials as normal or rapid (2% errors) but did not accurately classify the speaking rate of the syllables when they were excised from the sentences (25% errors). In contrast, listeners accurately identified the vowels produced in sentences spoken at both rates when presented the sentences and when presented the excised syllables blocked by speaking rate or randomized. Acoustical analysis showed that formant frequencies at syllable midpoint for vowels in sentence materials showed “target undershoot” relative to citation-form values, but little change over speech rate. Syllable durations varied systematically with vowel identity, speaking rate, and voicing of final consonant. Vowel-inherent-spectral-change was invariant in direction of change over rate and context for most vowels. The temporal location of maximum F1 frequency further differentiated spectrally adjacent lax and tense vowels. It was concluded that listeners were able to utilize these rate- and context-independent dynamic spectrotemporal parameters to identify coarticulated vowels, even when sentential information about speaking rate was not available.
Acoustic pulse propagation near a right-angle wall
Authors: Liu Lanbo , Albert Donald G.
Published: March 2006

Experimental measurements were conducted around a right-angle wall to investigate the effect of this obstacle on sound propagation outdoors. Using small explosions as the source of the acoustic waves allowed reflected and diffracted arrivals to be discerned and investigated in detail. The measurements confirm that diffraction acts as a low-pass filter on acoustic waveforms in agreement with simple diffraction theory, reducing the peak pressure and broadening the waveform shape received by a sensor in the shadow zone. In addition, sensors mounted directly on the wall registered pressure doubling for nongrazing angles of incidence in line-of-sight conditions. A fast two-dimensional finite difference time domain (FDTD) model was developed and provided additional insight into the propagation around the wall. Calculated waveforms show good agreement with the measured waveforms.
Synchrony, Waves, and Spatial Hierarchies in the Spread of Influenza
Authors: Viboud Cécile , Bjørnstad Ottar N. , Smith David L. , Simonsen Lone , Miller Mark A. , Grenfell Bryan T.
Published: March 2006

Quantifying long-range dissemination of infectious diseases is a key issue in their dynamics and control. Here, we use influenza-related mortality data to analyze the between-state progression of interpandemic influenza in the United States over the past 30 years. Outbreaks show hierarchical spatial spread evidenced by higher pairwise synchrony between more populous states. Seasons with higher influenza mortality are associated with higher disease transmission and more rapid spread than are mild ones. The regional spread of infection correlates more closely with rates of movement of people to and from their workplaces (workflows) than with geographical distance. Workflows are described in turn by a gravity model, with a rapid decay of commuting up to around 100 km and a long tail of rare longer range flow. A simple epidemiological model, based on the gravity formulation, captures the observed increase of influenza spatial synchrony with transmissibility; high transmission allows influenza to spread rapidly beyond local spatial constraints.
Functional Mapping of the Nucleoprotein of Ebola Virus
Authors: Watanabe Shinji , Noda Takeshi , Kawaoka Yoshihiro
Published: March 2006

At 739 amino acids, the nucleoprotein (NP) of Ebola virus is the largest nucleoprotein of the nonsegmented negative-stranded RNA viruses, and like the NPs of other viruses, it plays a central role in virus replication. Huang et al. (Y. Huang, L. Xu, Y. Sun, and G. J. Nabel, Mol. Cell
10:
307-316, 2002) previously demonstrated that NP, together with the minor matrix protein VP24 and polymerase cofactor VP35, is necessary and sufficient for the formation of nucleocapsid-like structures that are morphologically indistinguishable from those seen in Ebola virus-infected cells. They further showed that NP is O glycosylated and sialylated and that these modifications are important for interaction between NP and VP35. However, little is known about the structure-function relationship of Ebola virus NP. Here, we examined the glycosylation of Ebola virus NP and further investigated its properties by generating deletion mutants to define the region(s) involved in NP-NP interaction (self-assembly), in the formation of nucleocapsid-like structures, and in the replication of the viral genome. We were unable to identify the types of glycosylation and sialylation, although we did confirm that Ebola virus NP was glycosylated. We also determined that the region from amino acids 1 to 450 is important for NP-NP interaction (self-assembly). We further demonstrated that these amino-terminal 450 residues and the following 150 residues are required for the formation of nucleocapsid-like structures and for viral genome replication. These data advance our understanding of the functional region(s) of Ebola virus NP, which in turn should improve our knowledge of the Ebola virus life cycle and its extreme pathogenicity.
Novel Insights into the Pathogenesis of the Graffi Murine Leukemia Retrovirus
Authors: Voisin Véronique , Barat Corinne , Hoang Trang , Rassart Eric
Published: March 2006

The Graffi murine leukemia virus (MuLV) was isolated in 1954 by Arnold Graffi, who characterized it as a myeloid leukemia-inducing retrovirus. He and his team, however, soon observed the intriguing phenomenon of hematological diversification, which corresponded to a decrease of myeloid leukemias and an increase of other types of leukemias. Recently, we derived two different molecular clones corresponding to ecotropic nondefective genomes that were named GV-1.2 and GV-1.4. The induced leukemias were classified as myeloid based on morphological analysis of blood smears. In this study, we further characterized the two variants of the Graffi murine retrovirus, GV-1.2 and GV-1.4, in three different strains of mice. We show that the Graffi MuLV is a multipotent retrovirus capable of inducing both lymphoid (T- and B-cell) and nonlymphoid (myeloid, erythroid, megakaryocytic) leukemia. Many of these are very complex with concomitant expression of different hematopoietic lineages. Interestingly, a high percentage of megakaryocytic leukemias, a type of leukemia rarely observed with MuLVs, arise in the FVB/n strain of mice. The genetic backgrounds of the different strains of mice influence greatly the results. Furthermore, the enhancer region, different for GV-1.2 and GV-1.4, plays a pivotal role in the disease specificity: GV-1.2 induces more lymphoid leukemias, and GV-1.4 induces more nonlymphoid ones.
Alternative splicing factor ASF/SF2 is down regulated in inflamed muscle
Authors: Xiong Z , Shaibani A , Li Y-P , Yan Y , Zhang S , Yang Y , Yang F , Wang H , Yang X-F
Published: March 2006

Background:In our recent studies, alternative splicing has been shown to have a major role in inflammation and autoimmune muscle diseases.

Aim:To examine the novel hypothesis that the expression of an essential alternative splicing factor, alternative splicing factor 2 (ASF/SF2), is modulated in muscle inflammation.

Methods:ASF/SF2 expression in muscle biopsy samples from eight patients with inflammatory myopathy and six non-myositic controls was determined by using western blot with anti-ASF/SF2 antibodies. To further elucidate the mechanism of reduced ASF/SF2 expression in inflamed muscle, differentiated C2C12 myotubes were stimulated with proinflammatory cytokine tumour necrosis factor α (TNFα), followed by western blot analysis of ASF/SF2 expression.

Results:ASF/SF2 expression in the muscle biopsy samples from patients with inflammatory myopathy was found to be lower (mean of relative densitometric units 41.1 (2SD 20.7)) than that of the non-myositic controls (mean of relative densitometric units 76.7 (39.6); p<0.05). In addition to this, ASF/SF2 expression was seen to be significantly down regulated (sevenfold) in C2C12 myotubes compared with expression variations in the β-actin control (0.62-fold; mean 1.22 (0.40); p<0.05).

Conclusion:Collectively, it is shown, for the first time, that alternative splicing factor ASF/SF2 is down regulated in autoimmune inflammatory myositis—potentially via a TNFα-mediated pathway. The development of (1) novel autoantigen isoform microarrays for disease diagnosis and prognosis; (2) novel autoantigen-tolerising treatments for autoimmune diseases; and (3) novel splicing-redirection treatments can be facilitated by the ongoing study of alternative splicing of autoantigen transcripts.
STANDARD MODEL BUNDLES OF THE HETEROTIC STRING
Authors: CURIO GOTTFRIED
Published: March 2006

We show how to construct supersymmetric three-generation models with gauge group and matter content of the Standard Model in the framework of non-simply-connected elliptically fibered Calabi–Yau manifolds Z. The elliptic fibration on a cover Calabi–Yau, where the model has six generations of SU(5) and the bundle is given via the spectral cover description, has a second section leading to the needed free involution. The relevant involution on the defining spectral data of the bundle is identified for a general Calabi–Yau of this type and invariant bundles are generally constructible.
GENERALIZED COMPLEX GEOMETRY AND THE PLANCK CONE
Authors: ISIDRO JOSÉ M.
Published: March 2006

Complex geometry and symplectic geometry are mirrors in string theory. The recently developed generalized complex geometry interpolates between the two of them. On the other hand, the classical and quantum mechanics of a finite number of degrees of freedom are respectively described by a symplectic structure and a complex structure on classical phase space. In this paper we analyze the role played by generalized complex geometry in the classical and quantum mechanics of a finite number of degrees of freedom. We identify generalized complex geometry as an appropriate geometrical setup for dualities. The latter are interpreted as transformations connecting points in the interior of the Planck cone with points in the exterior, and vice versa. The Planck cone bears some resemblance with the relativistic light-cone. However the latter cannot be traversed by physical particles, while dualities do connect the region outside the Planck cone with the region inside, and vice versa.
QUANTUM FIELD THEORY TOOLS: A MECHANISM OF MASS GENERATION OF GAUGE FIELDS
Authors: FLORES-BAEZ F. V. , GODINA-NAVA J. J. , ORDAZ-HERNANDEZ G.
Published: March 2006

We present a simple mechanism for mass generation of gauge fields for the Yang–Mills theory, where two gauge SU (N)-connections are introduced to incorporate the mass term. Variations of these two sets of gauge fields compensate each other under local gauge transformations with the local gauge transformations of the matter fields, preserving gauge invariance. In this way the mass term of gauge fields is introduced without violating the local gauge symmetry of the Lagrangian. Because the Lagrangian has strict local gauge symmetry, the model is a renormalizable quantum model. This model, in the appropriate limit, comes from a class of universal Lagrangians which define a new massive Yang–Mills theories without Higgs bosons.
QUASI-EXACTLY-SOLVABLE QUANTUM LATTICE SOLITONS
Authors: BRIHAYE YVES , DEBERGH NATHALIE , NININAHAZWE ANCILLA
Published: March 2006

We extend the exactly solvable Hamiltonian describing f quantum oscillators considered recently by J. Dorignac et al. We introduce a new interaction which we choose to be quasi-exactly solvable. The properties of the spectrum of this new Hamiltonian are studied as functions of the new coupling constant. We point out that both the original and the by us modified Hamiltonians are related to adequate Lie structures.
CONSTRAINING MSUGRA PARAMETERS WITH μ→eγ AND μ–e CONVERSION IN NUCLEI
Authors: YAGUNA CARLOS E.
Published: March 2006

We show that, in the MSSM with msugra boundary conditions and seesaw induced neutrino masses, the values of BR (μ→eγ) and the μ–e conversion rate in a nucleus constrain msugra parameters in a model independent way.
DARBOUX TRANSFORMATIONS FOR TIME-DEPENDENT SCHRÖDINGER EQUATIONS WITH EFFECTIVE MASS
Authors: SCHULZE-HALBERG AXEL
Published: March 2006

The formalism of Darboux transformations is established for time-dependent Schrödinger equations with an effective (position-dependent) mass. Explicit formulas are obtained for the transformed wave function and the difference between the original and the transformed potential. It is shown that for a noneffective mass our Darboux transformation reduces correctly to the well-known Darboux transformation.
CHIRAL QED IN TERMS OF CHIRAL BOSON WITH A GENERALIZED FADDEEVIAN REGULARIZATION
Authors: RAHAMAN ANISUR
Published: March 2006

Chiral QED with a generalized Faddeevian regularization is considered. Imposing a chiral constraint a gauged version of Floreanini–Jackiw Lagrangian is constructed. The imposition of the chiral constraint has spoiled the manifestly Lorentz covariance structure of the theory. The phase space structure for this theory has been determined in the present situation. It is found that spectrum changes drastically but it remains Lorentz invariant in its constrained (physical) subspace. Chiral fermion disappears from the spectra and the photon acquire mass as well. Poincaré algebra has been calculated to show physical Lorentz invariance explicitly.
UNIFICATION OF GRAVITATION, GAUGE FIELD AND DARK ENERGY
Authors: HUANG XIN-BING
Published: March 2006

This paper is composed of two correlated topics: (1) unification of gravitation with gauge fields; (2) the coupling between the daor field and other fields and the origin of dark energy. After introducing the concept of "daor field" and discussing the daor geometry, we indicate that the complex daor field has two kinds of symmetry transformations. Hence the gravitation and SU(1, 3) gauge field are unified under the framework of the complex connection. We propose a first-order nonlinear coupling equation of the daor field, which includes the coupling between the daor field and SU(1, 3) gauge field and the coupling between the daor field and the curvature, and from which Einstein's gravitational equation can be deduced. The cosmological observations imply that dark energy cannot be zero, and which will dominate the doom of our Universe. The real part of the daor field self-coupling equation can be regarded as Einstein's equation endowed with the cosmological constant. It shows that dark energy originates from the self-coupling of the space–time curvature, and the energy–momentum tensor is proportional to the square of coupling constant λ. The dark energy density given by our scenario is in agreement with astronomical observations. Furthermore, the Newtonian gravitational constant G and the coupling constant ∊ of gauge field satisfy G = λ2∊2.
X(3872) DIAGNOSTICS WITH DECAYS TO $D{\bar D}\gamma$
Authors: VOLOSHIN M. B.
Published: March 2006

It is pointed out that in the decays [Formula: see text] the possible "molecular" component of the X(3872) should give rise essentially only to a [Formula: see text] final state with a predictable spectrum, and should yield virtually no contribution to decays into D+D-γ. The latter final state with charged D mesons should however arise from the radiative decays of the short-distance core of the X(3872) through the transition X(3872) → ψ(3770)γ. Thus an observation of the radiative decays of X(3872) to pairs of neutral and charged D mesons would provide an insight into the internal dynamics of the X(3872) resonance.
LEPTOGENESIS WITH SUPERSYMMETRIC HIGGS TRIPLETS IN THE TEV REGION
Authors: SENAMI MASATO , YAMAMOTO KATSUJI
Published: March 2006

The leptogenesis with supersymmetric Higgs triplets is studied in the light of experimental verification in the TeV region. The lepton number asymmetry appears just after the inflation via multiscalar coherent evolution of Higgs triplets and antislepton on a flat manifold. If the Higgs triplet mass terms dominate over the negative thermal-log term for the Hubble parameter H comparable to the Higgs triplet mass MΔ, the asymmetry is fixed readily to some significant value by the redshift and rotation of these scalar fields, providing the sufficient lepton-to-entropy ratio nL/s ~ 10-10. This can be the case even with MΔ ~ 1 TeV for the reheating temperature T R ~ 106 GeV and the mass parameter M/λ ~ 1022 GeV of the nonrenormalizable superpotential terms relevant for leptogenesis.
SKYRMION FORMATION IN 1+1 DIMENSIONS WITH CHEMICAL POTENTIAL
Authors: KUMAR V. SUNIL , LAYEK BISWANATH , SRIVASTAVA AJIT M. , SANYAL SOMA , TIWARI VIVEK K.
Published: March 2006

Formation of topological objects during phase transitions has been discussed extensively in literature. In all these discussions, defects and antidefects form with equal probabilities. In contrast, many physical situations, such as formation of baryons in relativistic heavy-ion collisions at present energies, flux tube formation in superconductors in the presence of external magnetic field, and formation of superfluid vortices in a rotating vessel, require a mechanism which can bias (say) defects over antidefects. Such a bias can crucially affect defect–antidefect correlations, apart from its effects on defect density. In this paper we initiate an investigation for the basic mechanism of biased formation of defects. For Skyrmions in 1+1 dimensions, we show that incorporation of a chemical potential term in the effective potential leads to a domain structure where order parameter is spatially varying. We show that this leads to biased formation of Skyrmions.
SUPERSYMMETRIC RELATIVISTIC QUANTUM MECHANICS
Authors: HABARA YOSHINOBU , NIELSEN HOLGER B. , NINOMIYA MASAO
Published: March 2006

We present an attempt to formulate the supersymmetric and relativistic quantum mechanics in the sense of realizing supersymmetry on the single particle level, by utilizing the equations of motion which is equivalent to the ordinary second quantization of the chiral multiplet. The matrix formulation is used to express the operators such as supersymmetry generators and fields of the chiral multiplets. We realize supersymmetry prior to filling the Dirac sea.
THE MARGINAL OPERATORS FOR GAMES ON CONVEX GEOMETRIES
Authors: BILBAO J. M. , JIMÉNEZ N. , LEBRÓN E. , LÓPEZ J. J.
Published: March 2006

In this work we study situations in which communication among the players is not complete and it is represented by a family of subsets of the set of players. Although several models of partial cooperation have been proposed, we shall follow a model derived from the work of Faigle and Kern. We define the games on convex geometries and introduce marginal worth vectors and quasi-supermodular games. Furthermore, we analyze some properties of the marginal operators on the space of games on convex geometries.
MARINE SHIPPING TRADE AND INVASIVE SPECIES MANAGEMENT STRATEGIES
Authors: FERNANDEZ LINDA
Published: March 2006

Addressing the international threat of invasive species to biodiversity worldwide requires an international context due to the nature of the transboundary pollution. This paper presents a comparison of strategies to address the invasive species problem in noncooperative versus cooperative differential games. Asymmetry between the countries in terms of abatement costs and damages enables the investigation of sharing rules under cooperation. The empirical analysis includes data of maritime trade as a vector of invasive species pollution at ports along the Pacific coast of NAFTA countries. The Chander/Tulkens cost sharing rule induces countries to cooperate and achieve lower invasive species stock than under noncooperation.
A COMPUTATIONAL APPROACH TO THE COINCIDENCE OF EGALITARIAN SOLUTIONS FOR COST-SHARING GAMES
Authors: WOLFF REINER
Published: March 2006

The pre-nucleolus is a popular egalitarian solution concept for cost-sharing games. A drawback of this concept is that an associated cost allocation often cannot be calculated in polynomial time. Therefore, it would be convenient to know whether the pre-nucleolus of a particular game coincides with the outcome of a cost-allocation method which is computationally less demanding. We provide operational conditions for a coincidence of the pre-nucleolus (point) of a cost-sharing game and the center of the game's imputation set (CIS vector). These conditions can be checked with little computational effort as compared to the potential savings in terms of computation time of a general solution algorithm.
RELATIONAL TIME FOR SYSTEMS OF OSCILLATORS
Authors: MILBURN G. J. , POULIN DAVID
Published: March 2006

Using an elementary example based on two simple harmonic oscillators, we show how a relational time may be defined that leads to an approximate Schrödinger dynamics for subsystems, with corrections leading to an intrinsic decoherence in the energy eigenstates of the subsystem.
THE PHYSICS OF FACTORIZATION
Authors: MANN A. , REVZEN M. , ZAK J.
Published: March 2006

The Ndistinct prime numbers that make up a composite number M allow its bi-partitioning into pairs of two relatively prime factors. Each such pair defines a pair of conjugate representations. An example of such pairs of conjugate representations, each of which spans the M-dimensional space, are the kq representations, which are the most natural representations for periodic systems. Here, we emphasize their relevance to factorizations: the number of prime numbers that make up M relates directly to the number of conjugate pairs of kq representations. It is also shown how Schwinger's factorization procedure is used for reducing M-dimensional space into subspaces according to the prime numbers that make up M.
THERMODYNAMICS OF LADDERS
Authors: SCHULMAN L. S. , GAVEAU B.
Published: March 2006

The production of "work" in a number of chemical processes (of particular applicability to biology) is analyzed, and studied as a function of a system's internal and external parameters.
Chronic PKC-β activation in HT-29 Cl.19a colonocytes prevents cAMP-mediated ion secretion by inhibiting apical membrane current generation
Authors: Broughman James R. , Sun Limin , Umar Shahid , Scott Jason , Sellin Joseph H. , Morris Andrew P.
Published: March 2006

We investigated the effects of PKC-stimulating 12-deoxyphorbol 13-phenylacetate 20-acetate (DOPPA) and phorbol 12-myristate 13-acetate (PMA) phorbol esters on cAMP-dependent, forskolin (FSK)-stimulated, short-circuit Cl−current ( ISC-cAMP) generation by colonocyte monolayers. These agonists elicited different actions depending on their dose and incubation time; PMA effects at the onset (<5 min) were independent of cAMP agonist and were characterized by transient anion-dependent transcellular and apical membrane ISCgeneration. DOPPA failed to elicit similar responses. Whereas chronic (24 h) exposure to both agents inhibited FSK-stimulated transcellular and apical membrane ISC-cAMP, the effects of DOPPA were more complex: this conventional PKC-β-specific agonist also stimulated Ba2+-sensitive basolateral membrane-dependent facilitation of transcellular ISC-cAMP. PMA did not elicit a similar phenomenon. Prolonged exposure to high-dose PMA but not DOPPA led to apical membrane ISC-cAMP recovery. Changes in PKC α-, β1-, γ-, and ε-isoform membrane partitioning and expression correlated with these findings. PMA-induced transcellular ISCcorrelated with PKC-α membrane association, whereas low doses of both agents inhibited transcellular and apical membrane ISC-cAMP, increased PKC-β1, decreased PKC-β2membrane association, and caused reciprocal changes in isoform mass. During the apical membrane ISC-cAMP recovery after prolonged high-dose PMA exposure, an almost-complete depletion of cellular PKC-β1and a significant reduction in PKC-ε mass occurred. Thus activated PKC-β1and/or PKC-ε prevented, whereas activated PKC-α facilitated, apical membrane ISC-cAMP. PKC-β-dependent augmentation of transcellular ISC-cAMP at the level of the basolateral membrane demonstrated that transport events with geographically distinct subcellular membranes can be independently regulated by the PKC β-isoform.
Androstenediol administration after trauma-hemorrhage attenuates inflammatory response, reduces organ damage, and improves survival following sepsis
Authors: Szalay László , Shimizu Tomoharu , Suzuki Takao , Hsieh Ya-Ching , Choudhry Mashkoor A. , Schwacha Martin G. , Bland Kirby I. , Chaudry Irshad H.
Published: March 2006

Although androstenediol (adiol or 5-androstene-3β,17β-diol), a metabolite of dehydroepiandrosterone (DHEA), has protective effects following trauma-hemorrhage (T-H), it remains unknown whether administration of adiol has any salutary effects on the inflammatory response and outcome following a combined insult of T-H and sepsis. Male rats underwent T-H shock [mean arterial pressure (MAP) 40 mmHg for 90 min] followed by resuscitation. Adiol (1 mg/kg body wt) or vehicle was administered at the end of resuscitation. Sepsis was induced by cecal ligation and puncture (CLP) at 20 h after T-H or sham operation. Five hours after CLP, plasma and tissue samples were analyzed for cytokines (IL-6 and IL-10), MPO, neutrophil chemotactic factor (CINC-3), and liver injury (alanine aminotransferase and lactate dehydrogenase). In another group of rats, the gangrenous cecum was removed at 10 h after CLP, the cavity was irrigated with warm saline and closed in layers, and mortality was recorded over 10 days. T-H followed by CLP produced a significant elevation in plasma IL-6 and IL-10 levels, enhanced neutrophil cell activation, and resulted in liver injury. Adiol administration prevented the increase in cytokine production, neutrophil cell activation, and attenuated liver injury. Moreover, rats subjected to the combined insult, receiving vehicle or adiol, had a 50% and 6% mortality, respectively. Since adiol administration suppresses proinflammatory cytokines, reduces liver damage, and decreases mortality after the combined insult of T-H and sepsis, this agent appears to be a novel adjunct to fluid resuscitation for decreasing T-H-induced septic complications and mortality.
Apoptotic pathway in the rat small intestinal mucosa is different between fasting and ischemia-reperfusion
Authors: Fujise Takehiro , Iwakiri Ryuichi , Wu Bin , Amemori Sadahiro , Kakimoto Takashi , Yokoyama Fumie , Sakata Yasuhisa , Tsunada Seiji , Fujimoto Kazuma
Published: March 2006

We have previously demonstrated that fasting and ischemia-reperfusion (I/R) induced apoptosis in rat intestinal mucosa. It is widely accepted that apoptosis is induced through two main pathways. This study aimed to compare apoptotic pathways following fasting and I/R. Rats were divided into two groups: the I/R group involved occlusion of the superior mesenteric artery for 60 min, followed by 60-min reperfusion, whereas the fasting group involved fasting for 24 or 48 h. Intestinal apoptosis was assessed as percentage of fragmented DNA, by electrophoresis and by a terminal deoxynucleotidyl transferase mediated dUDP-biotin nick- end labeling (TUNEL) assay. Apoptotic proteins including death ligands/receptors and caspases were evaluated by Western blot analysis. Small intestinal mucosal height and mitochondrial dehydrogenase function were assessed. Fasting and I/R significantly induced intestinal apoptosis. Mucosal height was significantly decreased in fasting rats, and mitochondrial dysfunction was induced only by I/R. Expressions of Fas, Fas ligand, and TNF-α type 1 receptor were enhanced in fasting and I/R rats. After I/R, expressions of cytochrome c and cleaved caspase-9 were significantly increased. In contrast, expressions of cleaved caspase-8 and cleaved caspase-3 increased in fasting rats. Fasting promoted mucosal apoptosis via a receptor-mediated type I apoptotic pathway in the rat small intestine, and I/R induced apoptosis via a mitochondria-mediated type II pathway.
Ethanol sensitizes NF-κB activation in pancreatic acinar cells through effects on protein kinase C-ε
Authors: Satoh Akihiko , Gukovskaya Anna S. , Reeve Joseph R. , Shimosegawa Tooru , Pandol Stephen J.
Published: March 2006

Although ethanol abuse is the most common cause of pancreatitis, the mechanism of alcohol's effect on the pancreas is not well understood. Previously, we demonstrated that in vitro ethanol treatment of pancreatic acinar cells augmented the CCK-8-induced activation of NF-κB, a key signaling system involved in the inflammatory response of pancreatitis. In the present study, we determine the role for individual PKC isoforms in the sensitizing effect of ethanol on NF-κB activation. Dispersed rat pancreatic acini were treated with and without ethanol and then stimulated with CCK-8; 100 nM CCK-8 caused both NF-κB and PKC-δ, -ε, and -ζ activation, whereas 0.1 nM CCK-8 did not increase PKC-ε, PKC-ζ, or NF-κB activity. CCK-8 (0.1 nM) did activate PKC-δ. PKC-ε activator alone did not cause NF-κB activation; however, together with 0.1 nM CCK-8, it caused NF-κB activation. Ethanol activated PKC-ε without affecting other PKC isoforms or NF-κB activity. Of note, stimulation of acini with ethanol and 0.1 nM CCK-8 resulted in the activation of PKC-δ, PKC-ε, and NF-κB. The NF-κB activation to 0.1 nM CCK-8 in ethanol-pretreated acini was inhibited by both PKC-δ inhibitor and PKC-ε inhibitor. Taken together, these results demonstrate the different modes of activation of PKC isoforms and NF-κB in acini stimulated with ethanol, high-dose CCK-8, and low-dose CCK-8, and furthermore suggest that activation of both PKC-ε and -δ is required for NF-κB activation. These results suggest that ethanol enhances the CCK-8-induced NF-κB activation at least in part through its effects on PKC-ε.
Regulation of Toll-like receptor 4-induced proasthmatic changes in airway smooth muscle function by opposing actions of ERK1/2 and p38 MAPK signaling
Authors: Shan Xiaoyin , Hu Aihua , Veler Haviva , Fatma Sumbul , Grunstein Judith S. , Chuang Sing , Grunstein Michael M.
Published: March 2006

Activation of Toll-like receptors (TLRs) on immune surveillance cells in the lung has been implicated in the pathobiology of allergic asthma, a condition associated with altered airway smooth muscle (ASM) contractility. Because ASM is known to directly respond to various proasthmatic stimuli, the potential role of TLR signaling in ASM in regulating airway expression of the proasthmatic phenotype was investigated. Cultured human ASM cells were found to express TLR4 and TLR9 mRNA transcripts and, whereas TLR9 stimulation had little effect, TLR4 activation with LPS elicited significant increases in IL-6 release and evoked proasthmatic-like changes in the constrictor and relaxation responsiveness of isolated rabbit ASM tissues. Complementary studies further demonstrated that the ASM responses to LPS were associated with activation of the ERK1/2 and p38 MAPK signaling pathways, IKK-mediated activation of NF-κB, and coupling of phosphorylated ERK1/2 with the p65 subunit of NF-κB. Moreover, the induced NF-κB activity and changes in ASM responsiveness were prevented in LPS-exposed ASM that were pretreated with inhibitors of ERK1/2 signaling, whereas inhibition of p38 MAPK augmented the proasthmatic responses to LPS. Finally, activation of p38 MAPK with anisomycin prevented both the LPS-induced stimulation of ERK1/2-mediated NF-κB activity and associated changes in ASM responsiveness. Collectively, these data support the novel concept that TLR4 activation in ASM elicits changes in ASM function that are regulated by opposing effects of MAPK signaling, wherein LPS-induced ERK1/2 activation mediates NF-κB-dependent proasthmatic-like changes in ASM function, whereas coactivation of p38 MAPK serves to homeostatically downregulate the proasthmatic effects of ERK1/2 activation.
Adjacent bronchus attenuates pulmonary arterial contractility
Authors: Lakshminrusimha Satyan , Russell James A. , Gugino Sylvia F. , Ryan Rita M. , Mathew Bobby , Nielsen Lori C. , Morin Frederick C.
Published: March 2006

Bronchus-derived relaxing factor (BrDRF) decreases contractility of newborn rat pulmonary arteries (PA) and is dependent on nitric oxide (NO) synthesis. In vivo, this factor appears to gain access via the adventitial side of the PA. However, the adventitia has been reported to be a barrier to NO. We studied the effect of an adjacent bronchus on PA contractility to norepinephrine in nine juvenile lambs in the presence and absence of inhibitors of the NO pathway (LNA, ODQ, and Rp-8-Br-PET-cGMPS), cytochrome P-450 inhibitor (17-ODYA), perivascular nerve activity blocker (TTX), and superoxide scavenger (tiron), and following disruption of bronchial epithelium. We also evaluated whether BrDRF was effective on both the endothelial and/or adventitial side of PA. Fifth-generation PA rings with and without an attached bronchus were contracted in standard baths with norepinephrine. PA were dissected, cut open, and placed in a sided chamber in which adventitial and endothelial sides of the PA were exposed to unattached bronchus separately. Norepinephrine (10−8 to 10−5 M) contractions were expressed as a fraction of maximal KCl (118 mM) contractions. Norepinephrine contractions were significantly reduced by the presence of an attached bronchus, an effect reversed by pretreatment with LNA, ODQ, and Rp-8-Br-PET-cGMPS, and removal of bronchial epithelium. Unattached bronchus in the bath perfusing the adventitial side was effective in inhibiting the contractile response in PA. NO gas relaxed PA when administered on the endothelial side only. We speculate that BrDRF is a diffusible factor that crosses the adventitia and stimulates production of NO within the PA.
Neonatal sympathectomy reduces NADPH oxidase activity and vascular resistance in spontaneously hypertensive rat kidneys
Authors: Schlüter Torsten , Grimm Rita , Steinbach Antje , Lorenz Gerd , Rettig Rainer , Grisk Olaf
Published: March 2006

Neonatal sympathectomy reduces arterial pressure in spontaneously hypertensive rats (SHR). In SHR transplanted with a kidney from sympathectomized SHR, arterial pressure was lower and less Na+ sensitive than in SHR transplanted with a kidney from hydralazine-treated SHR. This study was performed to identify underlying renal mechanisms. Tests for differential renal mRNA expression of nine a priori selected genes revealed robust differences for renal medullary expression of the NADPH oxidase subunit p47phox. Therefore, we investigated the effects of neonatal sympathectomy on renal mRNA expression of NADPH oxidase subunits, NADPH oxidase activity, and renal function. In 10-wk-old sympathectomized SHR fed a 0.6% NaCl diet, medullary p47phox and gp91phox expression was 40% less than in hydralazine-treated SHR. Also, after a 1.8% NaCl diet, medullary p47phox mRNA expression was lower in sympathectomized than in hydralazine-treated SHR. We found lower cortical (−30%, P < 0.01) and medullary (−30%, P < 0.05) NADPH oxidase activities in sympathectomized than in hydralazine-treated or untreated SHR. Glomerular filtration rate, renal blood flow, medullary blood flow, and fractional Na+ excretion in kidney grafts from sympathectomized and hydralazine-treated donors ( n = 8 per group) were similar at baseline and in response to a 20-mmHg rise in renal perfusion pressure. Renal vascular resistance was lower in kidneys from sympathectomized than hydralazine-treated donors (25 ± 2 vs. 32 ± 4 mmHg·min·ml−1, P < 0.05). The results indicate that the sympathetic nervous system contributes to the level of renal NADPH oxidase activity and to perinatal programming of alterations in renal vascular function that lead to elevated renal vascular resistance in SHR.
Activation of lateral parabrachial nucleus neurons restores blood pressure and sympathetic vasomotor drive after hypotensive hemorrhage
Authors: Blair Martha L. , Mickelsen Deanne
Published: March 2006

Lesions of the lateral parabrachial nucleus (LPBN) impair blood pressure recovery after hypotensive blood loss ( Am J Physiol Regul Integr Comp Physiol 280: R1141, 2001). This study tested the hypothesis that posthemorrhage blood pressure recovery is mediated by activation of neurons, located in the ventrolateral aspect of the LPBN (VL-LPBN), that initiates blood pressure recovery by restoring sympathetic vasomotor drive. Hemorrhage experiments (16 ml/kg over 22 min) were performed in unanesthetized male Sprague-Dawley rats prepared with bilateral ibotenate lesions or guide cannulas directed toward the external lateral subnucleus of the VL-LPBN. Hemorrhage initially decreased mean arterial pressure (MAP) from ∼100 mmHg control to 40–50 mmHg, and also decreased heart rate. In animals with sham lesions, MAP returned to 84 ± 4 mmHg by 40 min posthemorrhage, and subsequent autonomic blockade with hexamethonium reduced MAP to 53 ± 2 mmHg. In contrast, animals with VL-LPBN lesions remained hypotensive at 40 min posthemorrhage (58 ± 4 mmHg) and hexamethonium had no effect on MAP, implying a deficit in sympathetic tone. VL-LPBN lesions did not alter the renin response or the effect of vasopressin V1 receptor blockade after hemorrhage. Posthemorrhage blood pressure recovery was also significantly delayed by VL-LPBN infusion of the ionotropic glutamate receptor antagonist kynurenic acid. Both VL-LPBN lesions and VL-LPBN kynurenate infusion caused posthemorrhage bradycardia to be significantly prolonged. Bradycardia was reversed by hexamethonium or atropine, but did not contribute to posthemorrhage hypotension. Taken together, these data support the hypothesis that stimulation of VL-LPBN glutamate receptors mediates spontaneous blood pressure recovery by initiating restoration of sympathetic vasomotor drive.
Sexual dimorphism in the renin-angiotensin system in aging spontaneously hypertensive rats
Authors: Yanes Licy L. , Romero Damian G. , Iles Joshua W. , Iliescu Radu , Gomez-Sanchez Celso , Reckelhoff Jane F.
Published: March 2006

In young adult spontaneously hypertensive rats (SHR), mean arterial pressure (MAP) is higher in males than in females and inhibition of the renin-angiotensin system (RAS) eliminates this sex difference. After cessation of estrous cycling in female SHR, MAP is similar to that in male SHR. The purpose of this study was to determine the role of the RAS in maintenance of hypertension in aging male and female SHR. At 16 mo of age, MAP was similar in male and female SHR (183 ± 5 vs. 193 ± 8 mmHg), and chronic losartan (40 mg·kg−1·day−1 po for 3 wk) reduced MAP by 52% (to 90 ± 8 mmHg, P < 0.05 vs. control) in males and 37% (to 123 ± 11 mmHg, P < 0.05 vs. control) in females ( P < 0.05, females vs. males). The effect of losartan on angiotensin type 1 (AT1) receptor blockade was similar: MAP responses to acute doses of ANG II (62.5–250 ng/kg) were blocked to a similar extent in losartan-treated males and females. F2-isoprostane excretion was reduced with losartan more in males than in females. There were no sex differences in plasma renin activity, plasma angiotensinogen or ANG II, or renal expression of AT1 receptors, angiotensin-converting enzyme, or renin. However, renal angiotensinogen mRNA and protein expression was higher in old males than females, whereas renal ANG II was higher in old females than males. The data show that, in aging SHR, when blood pressures are similar, there remains a sexual dimorphism in the response to AT1 receptor antagonism, and the differences may involve sex differences in mechanisms responsible for oxidative stress with aging.
Leptin inhibits swallowing in rats
Authors: Félix Bernadette , Jean André , Roman Claude
Published: March 2006

Swallowing is under the control of premotoneurons located in the medullary solitary tract nucleus. Although rats with transected midbrain do not seek out food, they are able to ingest food present near the mouth, and acute food deprivation induces an increase in food intake. Leptin is a satiety signal that regulates feeding behavior. Because leptin receptors are found within the caudal brainstem, and because food intake is regulated in midbrain transected rats, this study tested the hypothesis that leptin is able to modify the activity of premotoneurons involved in swallowing. Leptin was microinjected at the subpostremal level of the medullary solitary tract nucleus in anesthetized Wistar rats. Electromyographic electrodes in sublingual muscles allowed recording of swallowing induced by stimulation of sensitive fibers of the superior laryngeal nerve. Repeated stimulation induced rhythmic swallowing. Microinjection of leptin (0.1 pg and 0.1 ng) in the swallowing center induced an inhibition of rhythmic swallowing (latency of <30 s) as shown by the reduced number and strength of electromyographic activities, which could last several minutes. The threshold of the leptin-induced inhibition was close to 0.1 pg. Interestingly, the inhibitory effect of leptin was not observed in leptin receptor-deficient Zucker rats. Here we show that, in Wistar rats, leptin already known to modulate the discharge of medullary solitary tract nucleus-sensitive neurons involved in satiety reflexes can also modify the activity of swallowing premotoneurons, thereby inhibiting an essential motor component of feeding behavior.
Effect of sex on perception of rectosigmoid stimuli in irritable bowel syndrome
Authors: Chang Lin , Mayer Emeran A. , Labus Jennifer S. , Schmulson Max , Lee Oh Young , Olivas Teresa I. , Stains Jean , Naliboff Bruce D.
Published: March 2006

In irritable bowel syndrome (IBS) patients, the relationship between sex and sensitivity to visceral stimuli is incompletely understood. Our aim was to evaluate the effect of sex on perceptual responses to visceral stimulation in IBS. Fifty-eight IBS patients (mean age 42 ± 1 yr; 34 men, 24 women) and 26 healthy controls (mean age 38 ± 3 yr; 9 men, 17 women) underwent barostat-assisted distensions of the rectum and sigmoid colon. Rectal discomfort thresholds were measured using a randomized, phasic distension paradigm before and after repeated noxious sigmoid stimulation (SIG, 60-mmHg pulses). Sex had a significant effect on rectal discomfort thresholds. Women with IBS were the most sensitive (lower thresholds [27 ± 2.7 mmHg] and higher ratings), with significantly lower rectal discomfort thresholds compared with men with IBS (38 ± 2.3 mmHg) and healthy women who were the least sensitive (41.9 ± 3.2 mmHg; both P < 0.01). There were no significant differences in rectal discomfort thresholds between healthy men (34 ± 4.3 mmHg) and men with IBS. Across both IBS and control groups, women demonstrated a significant lowering of discomfort thresholds after noxious sigmoid stimulation ( P < 0.01), while men did not. Sex significantly influences perceptual sensitivity to rectosigmoid distension. Women show greater perceptual responses to this paradigm.
Postnatal development of right atrial injection of capsaicin-induced apneic response in rats
Authors: Wang Rurong , Xu Fadi
Published: March 2006

Apnea and respiratory failure often occur in infants with pulmonary disease. Bronchopulmonary C-fiber (PCF)-mediated apnea is an important component of respiratory dysfunction. This study was undertaken to define the postnatal development of PCF-mediated apnea. The experiments were conducted in five groups of anesthetized, tracheotomized, and spontaneously breathing rats with ages at postnatal days P1–3, P7–9, P14–16, P21–23, and P56–58. Right atrial bolus injection of three doses of capsaicin (Cap), equivalent to 2, 4, and 8 μg/kg used previously in 450-g rats, was applied to stimulate PCFs. We found that 1) Cap-induced apneic response [percent change from the baseline expiratory duration (Te) values (ΔTe%)] and the sensitivity of this response (ΔTe%·μg−1) were significantly greater in the rats P10; 2) the Cap-induced apneas were vagally dependent in all rats tested; and 3) bivagotomy-induced prolongation of Te was much greater in the rats P10. From these findings we concluded that, compared with the older rats (>P10), the newborn rats have a stronger PCF-mediated respiratory inhibition that may contribute to infants' vulnerability to respiratory failure.