bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Two Residues within the LDL-A Module of Tva That Dictate the Altered Receptor Specificity of Mutant Subgroup A Avian Sarcoma and Leukosis Viruses
Authors: Rai Tia , Caffrey Michael , Rong Lijun
Published: November 2005

Avian sarcoma and leukosis virus subgroup A (ASLV-A) entry is mediated by interactions between the viral glycoprotein EnvA and its cognate receptor Tva. Previously, some interesting mutants of ASLV-A have been selected by others which can use chicken Tva, but not quail Tva, for efficient entry. The mutant phenotypes are caused by two point mutations within the surface subunit of EnvA (S. L. Holmen, D. C. Melder, and M. J. Federspiel, J. Virol.75:726-737, 2001). In this study, we have shown that the altered receptor specificity maps to the LDL-A module of Tva. Further, we have identified two residues in the chicken LDL-A module that allow more efficient viral entry by the mutant viruses. These results demonstrate that the altered receptor specificity of the mutant viruses is determined by specific interactions with residues in the LDL-A module of Tva.
Sensitization to Apoptosis Underlies Kras
D12
-Dependent Oncolysis of Murine C26 Colorectal Carcinoma Cells by Reovirus T3D
Authors: Smakman Niels , van den Wollenberg Diana J. M. , Rinkes Inne H. M. Borel , Hoeben Rob C. , Kranenburg Onno
Published: November 2005

Reovirus T3D is an oncolytic agent that preferentially targets tumor cells expressing an activated
Ras
oncogene. Ras signaling interferes with the cellular stress response that inhibits translation of reovirus RNAs. Murine C26 colorectal carcinoma cells express a mutant Kras
D12
gene. Reovirus T3D efficiently kills C26 cells, but not C26 cells in which the Kras
D12
mRNA is stably repressed by expression of Kras
D12
-directed short-hairpin RNAs. Surprisingly, neither reovirus T3D protein synthesis nor T3D virus yields were suppressed by deletion of Kras
D12
. Rather, reovirus-induced tumor cell apoptosis was completely abrogated as a result of
Kras
knockdown. We conclude that sensitization of C26 tumor cells to reovirus-induced apoptosis underlies the Ras dependency of reovirus T3D oncolysis.
Tat
28-35
SL8-Specific CD8
+
T Lymphocytes Are More Effective than Gag
181-189
CM9-Specific CD8
+
T Lymphocytes at Suppressing Simian Immunodeficiency Virus Replication in a Functional In Vitro Assay
Authors: Loffredo John T. , Rakasz Eva G. , Giraldo Juan Pablo , Spencer Sean P. , Grafton Kelly K. , Martin Sarah R. , Napoé Gnankang , Yant Levi J. , Wilson Nancy A. , Watkins David I.
Published: November 2005

Epitope-specific CD8
+
T lymphocytes may play an important role in controlling human immunodeficiency virus (HIV)/simian immunodeficiency virus replication. Unfortunately, standard cellular assays do not measure the antiviral efficacy (the ability to suppress virus replication) of CD8
+
T lymphocytes. Certain epitope-specific CD8
+
T lymphocytes may be better than others at suppressing viral replication. We compared the antiviral efficacy of two immunodominant CD8
+
T lymphocyte responses—Tat
28-35
SL8 and Gag
181-189
CM9—by using a functional in vitro assay. Viral suppression by Tat-specific CD8
+
T lymphocytes was consistently greater than that of Gag-specific CD8
+
T lymphocytes. Such differences in antigen-specific CD8
+
-T-lymphocyte efficacy may be important for selecting CD8
+
T lymphocyte epitopes for inclusion in future HIV vaccines.
NEW RESULTS FROM CLEO III AND CLEO-c
Authors: NAPOLITANO JIM
Published: November 2005

We discuss recent results from the CLEO III and CLEO-c collaborations, with a focus on strong interaction dynamics. We also include some discussion of future plans.
LIGHT COMPOSITE HIGGS: LCH @ LHC
Authors: SANNINO FRANCESCO
Published: November 2005

Here I summarize some of the salient features of technicolor theories with technifermions in higher dimensional representations of the technicolor gauge group. The expected phase diagram as function of number of flavors and colors for the two index (anti)symmetric representation of the gauge group is reviewed. After having constructed the simplest walking technicolor theory one can show that it is not at odds with the precision measurements. The simplest theory also requires, for consistency, a fourth family of heavy leptons. The latter may result in an interesting signature at LHC. In the case of a fourth family of leptons with ordinary lepton hypercharge the new heavy neutrino can be a natural candidate of cold dark matter. New theories will also be proposed in which the critical number of flavors needed to enter the conformal window is higher than in the one with fermions in the two-index symmetric representation, but lower than in the walking technicolor theories with fermions only in the fundamental representation of the gauge group. Due to the near conformal/chiral phase transition the composite Higgs is very light compared to the intrinsic scale of the technicolor theory. For the two technicolor theory the composite Higgs mass is predicted not to exceed 150 GeV.
TWISTED MASS LATTICE QCD AND HADRON PHENOMENOLOGY
Authors: ABDEL-REHIM ABDOU M. , LEWIS RANDY , WOLOSHYN R. M.
Published: November 2005

Lattice QCD simulations with a twisted mass term (tmLQCD) offer solutions to problems associated with simulations using Wilson fermions and a standard mass term. A summary of recent results from quenched simulations using tmLQCD at maximal twist for the pion form factor and hadron spectrum is presented.
J/Ψ DISSOCIATION AND ADLER'S THEOREM
Authors: BOURQUE ALEX , GALE CHARLES , HAGLIN KEVIN L.
Published: November 2005

Effective Lagrangian models of charmonium have recently been used to estimate dissociation cross sections with light hadrons. Detailed study of the symmetry properties reveals possible shortcomings relative to chiral symmetry. We therefore propose a new Lagrangian and point out distinguishing features amongst the different approaches. Using the newly proposed Lagrangian, which exhibits SU L (4) × SU R (4) symmetry and complies with Adler's theorem, we find dissociation cross sections with pions that are reduced in an energy dependent way, with respect to cases where the theorem is not fulfilled.
GENERALIZED SIGMA MODEL DESCRIPTION OF THE LIGHT J = 0 MESONS
Authors: FARIBORZ AMIR H. , JORA RENATA , SCHECHTER JOSEPH
Published: November 2005

Within a linear sigma model framework, possible mixing between two chiral nonets (a two quark nonet, and a four quark nonet) below 2 GeV is studied. Incorporating the U (1)A behavior of the underlying QCD, and working in the isospin invariant limit, the mass spectra of the I = 0, I = 1/2 and I = 1 pseudoscalars, and the I = 1/2 scalars are studied, and estimates of their quark content are presented. It is found, as expected, that the ordinary and the excited pseudoscalars generally have much less two and four quark admixtures compared to the respective scalars. As by-products, several quantities such as the four quark vacuum condensate, and the decay constant of excited states are predicted.
DYNAMICAL ENTANGLEMENT IN PARTICLE SCATTERING
Authors: HARSHMAN N. L.
Published: November 2005

This paper explores the connections between particle scattering and quantum information theory in the context of the non-relativistic, elastic scattering of two spin-1/2 particles. An untangled, pure, two-particle in-state is evolved by an S-matrix that respects certain symmetries and the entanglement of the pure out-state is measured. The analysis is phrased in terms of unitary, irreducible representations (UIRs) of the symmetry group in question, either the rotation group for the spin degrees of freedom or the Galilean group for non-relativistic particles. Entanglement may occurs when multiple UIRs appear in the direct sum decomposition of the direct product in-state, but it also depends of the scattering phase shifts.
ISOSPIN SYMMETRY BREAKING IN B → K*γ DECAY DUE TO AN EXTRA GENERATION OF VECTOR QUARKS
Authors: AHMADY MOHAMMAD R. , CHISHTIE FARRUKH
Published: November 2005

The extra contributions due to an extra generation of vector-like quarks to the isospin symmetry breaking observable associated with the radiative B → K*γ decay is obtained. It is shown that this additional contribution is sensitive to the nonunitarity parameter Usb, which is a measure of the the strength of the non-zero tree-level flavor changing neutral current in this model. The significance of this result is that, once accurate experimental results on the isospin asymmetry becomes available, one can constrain the Usb independent of the mass of the extra quarks and so a much more stringent acceptable model parameter space could be obtained.
STARTLING EQUIVALENCES IN THE HIGGS-GOLDSTONE SECTOR BETWEEN RADIATIVE AND LOWEST-ORDER CONVENTIONAL ELECTROWEAK SYMMETRY BREAKING
Authors: CHISHTIE F. A. , ELIAS V. , STEELE T. G.
Published: November 2005

For the Higgs boson mass of ~ 220 GeV expected to arise from radiative electroweak symmetry breaking, we find the same lowest-order expressions as would be obtained from conventional electroweak symmetry breaking, given the same Higgs boson mass, for Higgs-Goldstone sector scattering processes identified with [Formula: see text], [Formula: see text], as well as for Higgs boson decay widths [Formula: see text], H → ZLZL. The radiatively broken case, however, leads to an order of magnitude enhancement over lowest-order conventional symmetry breaking for scattering processes [Formula: see text], ZLZL → HH, as well as a factor of ~ 30 enhancement for HH → HH.
IMPLICATIONS OF μ ↔ τ SYMMETRY ON NEUTRINOS AND LEPTOGENESIS
Authors: NASRI SALAH
Published: November 2005

We discuss a model based on μ ↔ τ symmetry acting in the lepton sector, which leads to maximal atmospheric mixing angle and θ13 = 0. We show that in the symmetric limit the lepton asymmetry ∊l of the universe can be given in a simple form in terms of the neutrino oscillation parameters. We also find that for the case of two right handed neutrinos ∊l, constrain the symmetry breaking parameter θ13 to be in range 0.1 to 0.2 depending on the leptonic CP violation phase.
TWISTED POINCARE GROUP AND SPIN-STATISTICS
Authors: PINZUL ALEKSANDR
Published: November 2005

Recently it has been shown that it is possible to retain the Lorentz-invariant interpretation of the non-commutative field theory.1,2,3 This was achieved by the means of the twisted action of the Poincaré group on the tensor product of the fields. We investigate the consequences of this approach for the quantized fields.
BETA FUNCTIONS FOR DOUBLE-TRACE COUPLINGS IN ORBIFOLD GAUGE THEORIES
Authors: DYMARSKY A. , KLEBANOV I. R. , ROIBAN R.
Published: November 2005

We summarize calculation of one-loop beta functions in orbifolds of the [Formula: see text] SYM theory by a discrete subgroup Γ of the SU(4) R-symmetry, which are dual to string theory on AdS5 × S5/Γ, and the general strategy for determining whether there is a fixed line passing through the origin of the coupling constant space. We emphasize the importance of decoupling the U(1) factors. We describe a class of non-supersymmetric field theories corresponding to orbifolds acting freely on the S5 which preserve some of its global symmetries. In this class we do not find any large N non-supersymmetric theories with fixed lines passing through the origin. Connection of these results with closed string tachyon condensation in AdS5 × S5/Γ is discussed.
SOUND WAVES IN STRONGLY COUPLED NON-CONFORMAL GAUGE THEORY PLASMA
Authors: BENINCASA PAOLO
Published: November 2005

Gauge/string correspondence provides an efficient method to investigate gauge theories. In this talk we discuss the results of the paper (to appear) by P. Benincasa, A. Buchel and A. O. Starinets, where the propagation of sound waves is studied in a strongly coupled non-conformal gauge theory plasma. In particular, a prediction for the speed of sound as well as for the bulk viscosity is made for the [Formula: see text] gauge theory in the high temperature limit. As expected, the results achieved show a deviation from the speed of sound and the bulk viscosity for a conformal theory. It is pointed out that such results depend on the particular gauge theory considered.
NONCOMMUTATIVITY VS. TRANSVERSALITY IN QED IN A STRONG MAGNETIC FIELD
Authors: HASHIMOTO MICHIO
Published: November 2005

Quantum electrodynamics (QED) in a strong constant magnetic field is investigated from the viewpoint of its connection with noncommutative QED. It turns out that within the lowest Landau level (LLL) approximation the 1-loop contribution of fermions provides an effective action with the noncommutative U(1) NC gauge symmetry. As a result, the Ward identities connected with the initial U(1) gauge symmetry are broken down in the LLL approximation. On the other hand, it is shown that the sum over the infinite number of the higher Landau levels (HLL's) is relevant despite the fact that each contribution of the HLL is suppressed. Owing to this nondecoupling phenomenon the transversality is restored in the whole effective action. The kinematic region where the LLL contribution is dominant is also discussed.
PHOTONIC PATTERN FABRICATION IN FUSED SILICA, BK7, ANDGe-DOPED BOROPHOSPHOSILICA GLASS BY A FEMTOSECOND LASER
Authors: LEE G. J. , JEONG Y. H. , LEE J. J. , OH C. H. , KIM E. K. , LEE Y. P. , CHO K. H. , SHIN D. W.
Published: November 2005

Photonic patterns were fabricated in fused silica, BK7, and Ge -doped borophosphosilica glass ( Ge -BPSG) using a focused femtosecond (fs)-laser beam. By focusing tens to hundreds of μJ fs-laser beam with a 10x microscope objective, we inscribed the semi-circular cavity patterns on the fused silica and the BK7. The inscribed hole diameters are 28 μm (fused silica) and 11 μm (BK7) at an input fluence of 71 J/cm2. This circular-cavity patterning is ascribed to the ablation via the multi-photon absorption process. For the application to functional devices, the surface relief gratings (SRGs) were made in fused silica and BK7 by focusing the fs-laser beam on the glass surface with a cylindrical lens and by translating the sample in the direction perpendicular to the focus line. The first-order diffraction efficiencies of the prepared SRGs are 34% (fused silica) and 14% (BK7). A refractive-index grating was also fabricated in the Ge -BPSG by using the two-beam interference method. The maximum index modulation of 2.5 × 10-3was obtained for 20,000 laser shots of 73 mJ/cm2per pulse. It is thought that the index modification occurs through the defect formation by the fs-laser irradiation.
SYNTHESIS OF NOVEL Y-TYPE POLYURETHANES WITH HIGH THERMAL STABILITY OF DIPOLE ALIGNMENT AND THEIR ELECTRO-OPTIC PROPERTIES
Authors: LEE JU-YEON , JUNG WON-TAEK , RHEE BUM KU
Published: November 2005

3,4-di-(2′-hydroxyethoxy)benzylidenemalononitrile (3) was prepared and condensed with 2,4-toluenediisocyanate, 1,6-hexamethylenediisocyanate and 3,3′-dimethoxy-4,4′-biphenylenediisocyanate to yield novel Y-type polyurethanes (4-6) containing 3,4-dioxybenzylidenemalononitrile groups as nonlinear optical (NLO) chromophores, which are parts of the polymer backbones. The resulting polyurethanes 4-6 were soluble in common organic solvents such as acetone and DMSO. Polymers 4-6 exhibited a thermal stability up to 260°C from thermogravimetric analysis (TGA) with differential scanning calorimetry (DSC) with T g values in the range of 96–152°C. The SHG coefficients (d33) of poled polymer films were around 6.8 × 10-9 esu. These poled polymers exhibited a high thermal stability of dipole alignment even at 20°C higher than T g , and no SHG decay was observed below 175°C due to the partial main chain character of the polymer structure, which is acceptable for NLO device applications.
PULSED INTRACAVITY OPTICAL PARAMETRIC OSCILLATOR WITH HIGH AVERAGE POWER BASED ON PERIODICALLY POLED LiNbO3
Authors: CHO KI-HO , RHEE BUM KU , SASAKI YUZO , ITO HIROMASA
Published: November 2005

We report on output characteristics of the intracavity optical parametric oscillator at the degenerate wavelength of 2.128 μm based on 1-mm-thick PPLN pumped with 1064-nm pulses of a cw-diode-pumped, acousto-optically Q-switched Nd:YAG laser at 10 kHz repetition rate. A stable and high average output power as high as 6 W with a good beam quality of circular shape was attained without photorefractive damage at the crystal temperature of 143°C. We also observed pump-clamping effect with a singly resonant intracavity length of 5 cm and a pump pulse of 70-ns duration.
NONLINEAR OPTICAL PROPERTIES OF A HETERO-nipi STRUCTURE WITH COUPLED QUANTUM WELLS
Authors: KOST ALAN R. , CARTER RON R. , GARMIRE ELSA M. , HASENBERG THOMAS C.
Published: November 2005

A light-induced broadening of excitonic absorption features was investigated for a hetero n-i-p-i structure containing coupled quantum wells. Light-induced differential absorption as large as 5000 cm-1 was observed with an irradiance of only 280 mW/cm2. The largest absorption change was positive and occurred at 814 nm, just below the absorption edge for the non-illuminated sample. The nonlinear optical response for this structure is unlike the response for conventional n-i-p-i structures which exhibit decreasing absorption below the absorption edge. A corresponding refractive index change was calculated from absorption measurements using a modified Kramers–Kronig relation. The maximum change in the refractive index was 0.01 at 818 nm, a wavelength where the absorption was small for both the illuminated and non-illuminated samples. The origin of the excitonic broadening is explained with calculations for the transition energy and transition strength of the four lowest energy optical transitions for the coupled quantum wells. The relatively low irradiance required to excite the sample is attributed to long electron-hole recombination time, measured to be between 100 and 700 μs, depending on the irradiance on the sample.
METAL-DEFINED PASSIVE POLYMER OPTICAL WAVEGUIDES OPERATING AT BOTH 1.31 AND 1.55 μm WAVELENGTHS
Authors: KIM SEONGKU , GEARY K. , YUAN W. , FETTERMAN H. R. , ZHANG C. , WANG C. , STEIER W. H. , PARK G.-C. , KANG S.-J. , OH I. , JUNG W.-J.
Published: November 2005

We report experimental results demonstrating novel metal-defined passive polymer optical waveguides with low loss in electro-optic polymers for the first time. The polymer optical waveguides are created using a metal film on the top of an upper cladding without any conventional etching process. The fabricated waveguides have excellent lateral optical mode confinement at both 1.31 and 1.55 μm wavelengths, resulting in a fiber-to-lens optical insertion loss of ~7 dB at 1.55 μm and ~4.5 dB at 1.31 μm wavelength in 3.5 cm long devices. We also present the optical loss dependence of the waveguides as a function of optical wavelength. These results may be used in the complex design of integrated polymer lightwave circuits that require a simpler and inexpensive fabrication process.
DYNAMICAL ADDRESSING OPTICAL INTERCONNECTION BASED ON ONE-DIMENSIONAL NONLINEAR PHOTONIC CRYSTAL
Authors: CHEN MING , LI CHUNFEI , XU MAI , WANG WEIBIAO , MA SHAOJIE , XIA YUXUE , LIU DALI
Published: November 2005

A dynamical addressing device for optical interconnection based on one-dimensional nonlinear photonic crystal made on the planar waveguide was designed and fabricated. The dynamical interconnection is performed by controlling the power density of the control light. In our device, when increasing the power density of the control light from 0 to 2.60 × 105 W/cm2, the angle of the signal beam can be changed by about 2°. This kind of devices is promising for use in all-optical interconnection, optical information processing and optical communication.
Hypertonic saline enhances neutrophil elastase release through activation of P2 and A3 receptors
Authors: Chen Yu , Hashiguchi Naoyuki , Yip Linda , Junger Wolfgang G.
Published: November 2005

Hypertonic saline (HS) holds promise as a novel resuscitation fluid for the treatment of trauma patients because HS inhibits polymorphonuclear neutrophil (PMN) activation and thereby prevents host tissue damage and associated posttraumatic complications. However, depending on conditions of cell activation, HS can increase PMN degranulation, which could exacerbate tissue damage in trauma victims. The cellular mechanism by which HS increases degranulation is unknown. In the present study, we tested whether HS-induced ATP release from PMN and feedback via P1 and/or P2 receptors may be involved in the enhancement of degranulation by HS. We found that HS enhances elastase release and ERK and p38 MAPK activation when HS is added after activation of PMN with formyl peptide (fMLP) or phorbol ester (PMA). Agonists of P2 nucleotide and A3 adenosine receptors mimicked these enhancing effects of HS, whereas antagonists of A3 receptors or removal of extracellular ATP with apyrase diminished the response to HS. A1 adenosine receptor antagonists increased the enhancing effect of HS, whereas A1 receptor agonists inhibited elastase release. These data suggest that HS upregulates degranulation via ATP release and positive feedback through P2 and A3 receptors. We propose that these feedback mechanisms can serve as potential pharmacological targets to fine-tune the clinical effectiveness of HS resuscitation.
HMGB1 is secreted by immunostimulated enterocytes and contributes to cytomix-induced hyperpermeability of Caco-2 monolayers
Authors: Liu Shiguang , Stolz Donna B. , Sappington Penny L. , Macias Carlos A. , Killeen Meaghan E. , Tenhunen Jyrki J. , Delude Russell L. , Fink Mitchell P.
Published: November 2005

High-mobility group box 1 (HMGB1), a cytokine-like proinflammatory protein, is secreted by activated macrophages and released by necrotic cells. We hypothesized that immunostimulated enterocytes might be another source for this mediator. Accordingly, Caco-2 cells or primary mouse intestinal epithelial cells (IECs) were incubated with “cytomix” (a mixture of TNF, IL-1β, and IFN-γ) for various periods. HMGB1 in cell culture supernatants was detected by Western blot analysis and visualized in Caco-2 cells with the use of fluorescence confocal and immunotransmission electron microscopy. Caco-2 cells growing on filters in diffusion chambers were stimulated with cytomix for 48 h in the absence or presence of anti-HMGB1 antibody, and permeability to fluorescein isothiocyanate-dextran (average molecular mass, 4 kDa; FD4) was assessed. Cytomix-stimulated Caco-2 cells secreted HMGB1 into the apical but not the basolateral compartments of diffusion chambers. Although undetectable at 6 and 12 h after the start of incubation with cytomix, HMGB1 was present in supernatants after 24 h of incubation. HMGB1 secretion by Caco-2 monolayers also was induced when the cells were exposed to FSL-1, a Toll-like receptor (Tlr)-2 agonist, or flagellin, a Tlr5 agonist, but not lipopolysaccharide, a Tlr4 agonist. Cytomix also induced HMGB1 secretion by primary IECs. Cytoplasmic HMGB1 is localized within vesicles in Caco-2 cells and is secreted, at least in part, associated with exosomes. Incubating Caco-2 cells with cytomix increased FD4 permeation, but this effect was significantly decreased in the presence of anti-HMGB1 antibody. Collectively, these data support the view that HMGB1 is secreted by immunostimulated enterocytes. This process may exacerbate inflammation-induced epithelial hyperpermeability via an autocrine feedback loop.
The depressive effect of Pi on the force-pCa relationship in skinned single muscle fibers is temperature dependent
Authors: Debold E. P. , Romatowski J. , Fitts R. H.
Published: November 2005

Increases in Pi combined with decreases in myoplasmic Ca2+ are believed to cause a significant portion of the decrease in muscular force during fatigue. To investigate this further, we determined the effect of 30 mM Pi on the force-Ca2+ relationship of chemically skinned single muscle fibers at near-physiological temperature (30°C). Fibers isolated from rat soleus (slow) and gastrocnemius (fast) muscle were subjected to a series of solutions with an increasing free Ca2+ concentration in the presence and absence of 30 mM Pi at both low (15°C) and high (30°C) temperature. In slow fibers, 30 mM Pi significantly increased the Ca2+ required to elicit measurable force, referred to as the activation threshold at both low and high temperatures; however, the effect was twofold greater at the higher temperature. In fast fibers, the activation threshold was unaffected by elevating Pi at 15°C but was significantly increased at 30°C. At both low and high temperatures, 30 mM Pi increased the Ca2+ required to elicit half-maximal force (pCa50) in both slow and fast fibers, with the effect of Pi twofold greater at the higher temperature. These data suggest that during fatigue, reductions in the myoplasmic Ca2+ and increases in Pi act synergistically to reduce muscular force. Consequently, the combined changes in these ions likely account for a greater portion of fatigue than previously predicted based on studies at lower temperatures or high temperatures at saturating Ca2+ levels.
Stretch increases alveolar epithelial permeability to uncharged micromolecules
Authors: Cavanaugh Kenneth J. , Cohen Taylor S. , Margulies Susan S.
Published: November 2005

We measured stretch-induced changes in transepithelial permeability in vitro to uncharged tracers 1.5–5.5 Å in radius to identify a critical stretch threshold associated with failure of the alveolar epithelial transport barrier. Cultured alveolar epithelial cells were subjected to a uniform cyclic (0.25 Hz) biaxial 12, 25, or 37% change in surface area (ΔSA) for 1 h. Additional cells served as unstretched controls. Only 37% ΔSA (100% total lung capacity) produced a significant increase in transepithelial tracer permeability, with the largest increases for bigger tracers. Using the permeability data, we modeled the epithelial permeability in each group as a population of small pores punctuated by occasional large pores. After 37% ΔSA, increases in paracellular transport were correlated with increases in the radii of both pore populations. Inhibition of protein kinase C and tyrosine kinase activity during stretch did not affect the permeability of stretched cells. In contrast, chelating intracellular calcium and/or stabilizing F-actin during 37% ΔSA stretch reduced but did not eliminate the stretch-induced increase in paracellular permeability. These results provide the first in vitro evidence that large magnitudes of stretch increase paracellular transport of micromolecules across the alveolar epithelium, partially mediated by intracellular signaling pathways. Our monolayer data are supported by whole lung permeability results, which also show an increase in alveolar permeability at high inflation volumes (20 ml/kg) at the same rate for both healthy and septic lungs.
Physiology of the esophageal pressure transition zone: separate contraction waves above and below
Authors: Ghosh Sudip K. , Janiak Patrick , Schwizer Werner , Hebbard Geoffrey S. , Brasseur James G.
Published: November 2005

Manometrically measured peristaltic pressure amplitude displays a well-defined trough in the upper esophagus. Whereas this manometric “transition zone” (TZ) has been associated with striated-to-smooth muscle fiber transition, the underlying physiology of the TZ and its role in bolus transport are unclear. A computer model study of bolus retention in the TZ showed discoordinated distinct contraction waves above and below. Our aim was to test the hypothesis that distinct upper/lower contraction waves above/below the manometric TZ are normal physiology and to quantify space-time coordination between tone and bolus transport through the TZ. Eighteen normal barium swallows were analyzed in 6 subjects with concurrent 21-channel high-resolution manometry and digital fluoroscopy. From manometry, the TZ center (nadir pressure amplitude) and the upper/lower margins of the pressure trough were objectively quantified. Using fluoroscopy, we quantified space-time trajectories of the bolus tail and bolus tail pressures and maximum intraluminal pressures proximal to the tail with their space-time trajectories. In every swallow, the bolus tail followed distinct trajectories above/below the TZ, separated by a well-defined spatial “jump” that terminated an upper contraction wave and initiated a lower contraction wave (3.32 ± 1.63 cm, P = 0.0004). An “indentation wave” always formed within the TZ distal to the upper wave, increasing in amplitude until the lower wave was initiated. As the upper contraction wave tail entered the TZ, it slowed and the tail pressure reduced rapidly, while indentation wave pressure increased to normal tail pressure values at the initiation of the lower wave. The TZ was a special zone of segmental contraction. The TZ is, physiologically, the transition from an upper contraction wave originating in the proximal striated esophagus to a lower contraction wave that moves into the distal smooth muscle esophagus. Complete bolus transport requires coordination of upper/lower waves and sufficient segmental squeeze to fully clear the bolus from the TZ during the transition period.
Measuring airway exchange of endogenous acetone using a single-exhalation breathing maneuver
Authors: Anderson Joseph C. , Lamm Wayne J. E. , Hlastala Michael P.
Published: November 2005

Exhaled acetone is measured to estimate exposure or monitor diabetes and congestive heart failure. Interpreting this measurement depends critically on where acetone exchanges in the lung. Health professionals assume exhaled acetone originates from alveolar gas exchange, but experimental data and theoretical predictions suggest that acetone comes predominantly from airway gas exchange. We measured endogenous acetone in the exhaled breath to evaluate acetone exchange in the lung. The acetone concentration in the exhalate of healthy human subjects was measured dynamically with a quadrupole mass spectrometer and was plotted against exhaled volume. Each subject performed a series of breathing maneuvers in which the steady exhaled flow rate was the only variable. Acetone phase III had a positive slope (0.054 ± 0.016 liter−1) that was statistically independent of flow rate. Exhaled acetone concentration was normalized by acetone concentration in the alveolar air, as estimated by isothermal rebreathing. Acetone concentration in the rebreathed breath ranged from 0.8 to 2.0 parts per million. Normalized end-exhaled acetone concentration was dependent on flow and was 0.79 ± 0.04 and 0.85 ± 0.04 for the slow and fast exhalation rates, respectively. A mathematical model of airway and alveolar gas exchange was used to evaluate acetone transport in the lung. By doubling the connective tissue (epithelium + mucosal tissue) thickness, this model predicted accurately ( R2 = 0.94 ± 0.05) the experimentally measured expirograms and demonstrated that most acetone exchange occurred in the airways of the lung. Therefore, assays using exhaled acetone measurements need to be reevaluated because they may underestimate blood levels.
Influence of gender and age on T-cell responses in a murine model of trauma-hemorrhage: differences between circulating and tissue-fixed cells
Authors: Schneider Christian P. , Schwacha Martin G. , Chaudry Irshad H.
Published: November 2005

Clinical studies indicate that peripheral blood lymphocyte functions are depressed following trauma; however, it is unclear whether tissue-fixed lymphocyte functions are also altered under those conditions. Moreover, the impact of gender and age on peripheral T-cell responses following trauma-hemorrhage (TH) are unknown. To study this, immature (∼3 wk of age), mature (∼7 wk of age), and aged (∼23 mo of age) male and proestrus female C3H/HeN mice were sham operated or subjected to trauma (i.e., midline laparotomy) and hemorrhagic shock (30 ± 5 mmHg for 90 min). Twenty-four hours after resuscitation, blood and splenocytes were harvested and T-cell functions assessed. In immature animals, TH induced an enhanced immune response in the splenic compartment and a suppressed response in the peripheral blood mononuclear cells (PBMC) that was independent of gender. Differential responses were observed in cells from mature mice. Splenic responses were enhanced following TH, independent of gender, whereas PBMC displayed gender dimorphism with suppressed proliferation and T-cell helper 1 responses in males but not in females. A similar pattern was observed in cells from aged mice. Splenic T cells from male mice displayed a suppressed CD4-to-CD8 ratio after TH, whereas no such change was observed in cells from proestrus females. In contrast, only PBMC from mature males displayed a suppressed CD4-to-CD8 ratio after TH. Thus gender differences exist in PBMC responses after TH that do not necessarily correlate with changes in the tissue-fixed compartment. Age is also an important factor in the immune responses after TH. In view of this, both gender and age should be taken into consideration in evaluating the immune status and in treatment of TH shock.
Persistent Sodium Currents and Repetitive Firing in Motoneurons of the Sacrocaudal Spinal Cord of Adult Rats
Authors: Harvey P. J. , Li Y. , Li X. , Bennett D. J.
Published: November 2005

Months after sacral spinal transection in rats (chronic spinal rats), motoneurons below the injury exhibit large, low-threshold persistent inward currents (PICs), composed of persistent sodium currents (Na PICs) and persistent calcium currents (Ca PICs). Here, we studied whether motoneurons of normal adult rats also exhibited Na and Ca PICs when the spinal cord was acutely transected at the sacral level (acute spinal rats) and examined the role of the Na PIC in firing behavior. Intracellular recordings were obtained from motoneurons of acute and chronic spinal rats while the whole sacrocaudal spinal cord was maintained in vitro. Compared with chronic spinal rats, motoneurons of acute spinal rats were more difficult to activate because the input resistance was 22% lower and resting membrane potential was hyperpolarized 4.1 mV further below firing threshold (−50.9 ± 6.2 mV). In acute spinal rats, during a slow voltage ramp, a PIC was activated subthreshold to the spike (at −57.2 ± 5.0 mV) and reached a peak current of 1.11 ± 1.21 nA. This PIC was less than one-half the size of that in chronic spinal rats (2.79 ± 0.94 nA) and usually was not large enough to produce bistable behavior (plateau potentials and self-sustained firing not present), unlike in chronic spinal rats. The PIC was composed of two components: a TTX-sensitive Na PIC (0.44 ± 0.36 nA) and a nimodipine-sensitive Ca PIC (0.78 ± 0.82 nA). Both were smaller than in chronic spinal rats (but with similar Na/Ca ratio). The presence of the Na PIC was critical for normal repetitive firing, because no detectable Na PIC was found in the few motoneurons that could not fire repetitively during a slow ramp current injection and motoneurons that had large Na PICs more readily produced repetitive firing and had lower minimum firing rates compared with neurons with small Na PICs. Furthermore, when the Na PIC was selectively blocked with riluzole, steady repetitive firing was eliminated, even though transient firing could be evoked on a rapid current step and the spike itself was unaffected. In summary, only small Ca and Na PICs occur in acute spinal motoneurons, but the Na PIC is essential for steady repetitive firing. We discuss how availability of monoamines may explain the variability in Na PICs and firing in the normal and spinal animals.
Tail Muscles Become Slow but Fatigable in Chronic Sacral Spinal Rats With Spasticity
Authors: Harris R. Luke W. , Bobet Jacques , Sanelli Leo , Bennett David J.
Published: November 2005

Paralyzed skeletal muscle sometimes becomes faster and more fatigable after spinal cord injury (SCI) because of reduced activity. However, in some cases, pronounced muscle activity in the form of spasticity (hyperreflexia and hypertonus) occurs after long-term SCI. We hypothesized that this spastic activity may be associated with a reversal back to a slower, less fatigable muscle. In adult rats, a sacral (S2) spinal cord transection was performed, affecting only tail musculature and resulting in chronic tail spasticity beginning 2 wk later and lasting indefinitely. At 8 mo after injury, we examined the contractile properties of the segmental tail muscle in anesthetized spastic rats and in age-matched normal rats. The segmental tail muscle has only a few motor units (<12), which were easily detected with graded nerve stimulation, revealing two clear motor unit twitch durations. The dominant faster unit twitches peaked at 15 ms and ended within 50 ms, whereas the slower unit twitches only peaked at 30–50 ms. With chronic injury, this slow twitch component increased, resulting in a large overall increase (>150%) in the fraction of the peak muscle twitch force remaining at 50 ms. With injury, the peak muscle twitch (evoked with supramaximal stimulation) also increased in its time to peak (+48.9%) and half-rise time (+150.0%), and decreased in its maximum rise (−35.0%) and decay rates (−40.1%). Likewise, after a tetanic stimulation, the tetanus half-fall time increased by 53.8%. Therefore the slow portion of the muscle was enhanced in spastic muscles. Consistent with slowing, posttetanic potentiation was 9.2% lower and the stimulation frequency required to produce half-maximal tetanus decreased 39.0% in chronic spinals. Interestingly, in spastic muscles compared with normal, whole muscle twitch force was 81.1% higher, whereas tetanic force production was 38.1% lower. Hence the twitch-to-tetanus ratio increased 104.0%. Inconsistent with overall slowing, whole spastic muscles were 61.5% more fatigable than normal muscles. Thus contrary to the classical slow-to-fast conversion that is seen after SCI without spasticity, SCI with spasticity is associated with a mixed effect, including a preservation/enhancement of slow properties, but a loss of fatigue resistance.
Prolonged Vibration of the Biceps Brachii Tendon Reduces Time to Failure When Maintaining Arm Position With a Submaximal Load
Authors: Mottram Carol J. , Maluf Katrina S. , Stephenson Jennifer L. , Anderson Melissa K. , Enoka Roger M.
Published: November 2005

Vibration reduces the amplitudes of the tendon jerk response and the Hoffmann and stretch reflexes in the muscle exposed to the vibration, yet does not alter the time to task failure when the task involves exerting a submaximal force against a rigid restraint. Because the amplitude of the stretch reflex is greater when a limb acts against a compliant load than a rigid restraint, the purpose was to determine the influence of prolonged tendon vibration on the time to failure when maintaining limb position with the elbow flexor muscles. Twenty-five healthy men performed the fatiguing contraction by maintaining elbow angle at 1.57 rad until failure while supporting a load equal to 20% of maximal voluntary contraction (MVC) force. The fatiguing contraction was performed on 3 separate days with different levels of vibration applied to the biceps brachii tendon: no vibration, subthreshold for a tonic vibration reflex (TVR), and suprathreshold for a TVR. MVC force before the fatiguing contraction was similar across the three sessions (mean of 3 sessions: 313 ± 54 N, P = 0.83). Despite a similar decline in MVC force after the fatiguing contraction across conditions (–18.0 ± 8.0%, P > 0.05), the time to task failure was 3.7 ± 1.4 min for the suprathreshold TVR condition, 4.3 ± 2.1 min for the subthreshold TVR condition, and 5.0 ± 2.2 min for the no-vibration condition ( P < 0 0.001). The average EMG of the elbow flexor muscles was similar ( P = 0.22) during the fatiguing contractions. However, the fluctuations in limb acceleration at task onset were greater for the suprathreshold TVR condition ( P < 0.01), but were not different between the subthreshold TVR and no-vibration conditions ( P ≥ 0.22). Furthermore, the difference in the SD of limb acceleration between the no-vibration and vibration conditions was correlated with the difference in time to failure for the no-vibration and subthreshold TVR conditions ( P = 0.03; r2 = 0.22), but not for the no-vibration and suprathreshold TVR conditions ( P = 0.90; r2 = 0.001). These findings indicate that prolonged vibration reduced the time to failure of a sustained contraction when subjects maintained limb position, suggesting that peripheral inputs to the motor neuron pool play a significant role in sustaining a contraction during tasks that require active control of limb position.
Dopamine Modulation of Honey Bee (Apis mellifera) Antennal-Lobe Neurons
Authors: Perk Christopher G. , Mercer Alison R.
Published: November 2005

Primary olfactory centers [antennal lobes (ALs)] of the honey bee brain are invaded by dopamine (DA)-immunoreactive neurons early in development (pupal stage 3), immediately before a period of rapid growth and compartmentalization of the AL neuropil. Here we examine the modulatory actions of DA on honey bee AL neurons during this period. Voltage-clamp recordings in whole cell configuration were used to determine the effects of DA on ionic currents in AL neurons in vitro from pupal bees at stages 4–6 of the nine stages of metamorphic adult development. In ∼45% of the neurons tested, DA (5–50 × 10−5M) reduced the amplitude of outward currents in the cells. In addition to a slowly activating, sustained outward current, DA reduced the amplitude of a rapidly activating, transient outward conductance in some cells. Both of the currents modulated by DA could be abolished by the removal of Ca2+from the external medium or by treatment of cells with charybdotoxin (2 × 10−8M), a blocker of Ca2+-dependent K+currents in the cells. Ca2+currents were not affected by DA, nor were A-type K+currents ( IA). Results suggest that the delayed rectifier-like current ( IKV) also remains intact in the presence of DA. Taken together, our data indicate that Ca2+-dependent K+currents are targets of DA modulation in honey bee AL neurons. This study lends support to the hypothesis that DA plays a role in the developing brain of the bee.
Authentic Indigenization and Liberation in the Theology of Canaan Sodindo Banana (1936–2003) of Zimbabwe
Authors: Thomas Norman
Published: November 2005

African theologies are most often classified as either theologies of inculturation, or of liberation. Canaan Banana was one of few African theologians who combine authentic indigenization and liberation in their thought. The author, who knew Rev. Banana personally, based his analysis on Banana's writings and on interpretations by other scholars. Banana's theology was influenced by his ecumenical leadership as a Methodist minister, studies in the United States, involvement in the liberation struggle, and national leadership as the first President of Zimbabwe. Banana's liberation perspective, in contrast to those of most South African black theologians, dealt with issues of class rather than of color. His political theology, articulated when he was president of Zimbabwe, focused on the relation of socialism and Christianity. For him liberation involved struggle and even armed struggle. In his last decade former President Banana began to articulate a prophetic "Combat Theology." Banana stimulated a heated discussion on biblical hermeneutics in southern Africa by proposing deletion from the Bible of passages used to justify oppression. Believing that God is revealed also through creation and African culture, he found creative myths and images of Jesus in the cultures of his own Shona and Ndebele peoples. His contribution is a theology that can help Christianity to be both indigenous and socially relevant in 21st century Africa.
What Makes Mission Christian?
Authors: Little Christopher
Published: November 2005

There is evidence to suggest that the contemporary evangelical missions movement is reformulating its missional role in the world. Through the widespread influence of holistic mission and the kingdom of God motif, the priority of proclamation is taking a back seat to addressing the socio-economic dilemmas of humankind. Yet such an emphasis falls short of accurately representing both Jesus and Paul who were constrained by a doxological approach to mission. If evangelical mission is to more clearly reflect biblical mission, then this doxological orientation must be recovered.
Ecumenical Dislodgings
Authors: Irvin Dale
Published: November 2005

Ecumenics and missions through much of the 20th century were closely related disciplines. In recent years mission studies has matured significantly in coming to grips with a new world Christian reality. The ecumenical movement on the other hand has not fared so well. A renewed effort to relate Christianity to its local projects across the historical landscape of the globe, which was intrinsic to the 20th century ecumenical project, is called for, along with a renewed effort to understand what fellowship and visible unity mean for world Christianity today. The ecumenical movement must become engaged in a fresh way in border crossing and territorial dislodging. Border crossing was intrinsic to the New Testament understanding of the faith. Moving to the margins, crossing social and cultural frontiers, defined the apostolic movement. The dispersal of the apostles was as fundamental to the Christian identity as their gathering in eucharistic unity. A consciousness of such dispersal is necessary for ecumenical life today. The modern missionary movement brought about such dispersal through its deterritorialization of the Christian religion. Those who continue to think that Christianity belongs to the West are still in the grips of the Christendom mentality. To this end Christianity must shed its territorial complex in order to recover its true identity. Ecumenical renewal will be found in being dislodged from its Christian homelands, and the entire Christian community is under the imperative not only to missionize, but to be missionized, to be transformed by the renewing of its collective and individual minds in this manner. To this end we need to become uncomfortable with inherited identities of language, tribe, and nation, to regard all lands and all identities, including our existing Christian ones as foreign places, in order to move in the light of the divine community that awaits us still.
Empowering as a Missional Concept vs. Empowerment as a Political Ideology
Authors: Kasambala Amon Eddie
Published: November 2005

The article contrasts the meaning of empowerment in a political ideological perspective with a Christian mission understanding of empowering as a process of reaching out to the other with the love of the triune God; Father, Son and Holy Spirit. It is argued that as far as the developing world is concerned there are many reasons for an empowering process in Christian mission, and one of them is an existing identity crisis facing churches in the developing countries (sometimes referred to as third world churches). The article also undertakes to work with a proposition that states that the solution to a perceived paternalism from the churches in the developed world over those in developing nations does not necessary lie in a moratorium call, however, it should be found in embracing a notion of empowering that creates an attitude of partnership between both churches. Three basic principles are proposed that should under gird this process; namely, Unconditional acceptance, Unconditional respect, Unconditional dignity. An African tale is given to illustrate the basic working assumptions and presuppositions of this article.