bluuebunny/crossref_metadata_2025 huggingface dataset:
Abolition of chondral mineralization by group III metabotropic glutamate receptors expressed in rodent cartilage
Authors: Wang Liyang , Hinoi Eiichi , Takemori Akihiro , Takarada Takeshi , Yoneda Yukio
Published: August 2005

Previous studies have demonstrated the functional expression by osteoblasts of glutamate (Glu) signaling machineries responsible for the stimulation of cell proliferation and differentiation in bone, while there is no information available on the expression of the Glu signaling system by cartilage to date.

In cultured mouse embryonic metatarsals isolated before vascularization, chondral mineralization was almost completely inhibited in the presence of the group III metabotropic Glu receptor (mGluR) agonist L‐(1)‐2‐amino‐4‐phosphonobutyrate (L‐AP4) in a manner sensitive to an antagonist, with the total length being unchanged.

A group II mGluR agonist was similarly more effective in inhibiting the mineralization than a group I mGluR agonist, while none of ionotropic GluR agonists drastically affected the mineralization.

Both histological and in situ hybridization analyses revealed that L‐AP4 specifically inhibited chondral mineralization, without apoptotic cell death, in cultured metatarsals.

In addition to the constitutive expression of mRNA for particular mGluRs in both cultured mouse metatarsals and rat costal chondrocytes, L‐AP4 significantly inhibited the accumulation of cyclic AMP by forskolin and parathyroid hormone in a manner sensitive to a group III mGluR antagonist in cultured chondrocytes.

Moreover, L‐AP4 drastically inhibited the expression of osteopontin mRNA in both cultured metatarsals and chondrocytes.

These results suggest that Glu may at least in part play a role as a signal mediator in mechanisms associated with chondral mineralization through the group III mGluR subtype functionally expressed by chondrocytes in rodent cartilage.

British Journal of Pharmacology (2005) 146, 732–743. doi:10.1038/sj.bjp.0706358
Rotational spectroscopy and equilibrium structures of S3 and S4
Authors: Thorwirth S. , McCarthy M. C. , Gottlieb C. A. , Thaddeus P. , Gupta H. , Stanton J. F.
Published: August 2005

The sulfur molecules thiozone S3 and tetrasulfur S4 have been observed in a supersonic molecular beam in the centimeter-wave band by Fourier transform microwave spectroscopy, and in the millimeter- and submillimeter-wave bands in a low-pressure glow discharge. For S3 over 150 rotational transitions between 10 and 458GHz were measured, and for S4 a comparable number between 6 and 271GHz. The spectrum of S3 is reproduced to within the measurement uncertainties by an asymmetric top Hamiltonian with three rotational and 12 centrifugal distortion constants; ten distortion constants, but an additional term to account for very small level shifts caused by interchange tunneling, are required to reproduce to comparable accuracy the spectrum of S4. Empirical equilibrium (reemp) structures of S3 and S4 were derived from experimental rotational constants of the normal and sulfur-34 species and vibrational corrections from coupled-cluster theory calculations. Quantum chemical calculations show that interchange tunneling occurs because S4 automerizes through a transition state with D2h symmetry which lies about 500cm−1 above the two equivalent C2υ minima on the potential energy surface.
Photoluminescence behavior of Si nanocrystals as a function of the implantation temperature and excitation power density
Authors: Sias U. S. , Amaral L. , Behar M. , Boudinov H. , Moreira E. C. , Ribeiro E.
Published: August 2005

In this work we present a study of photoluminescence (PL) on Si nanocrystals (NC) produced by ion implantation on SiO2 targets at temperatures ranging between room temperature and 800°C and subsequently annealed in N2 atmosphere. The PL measurements were performed at low excitation power density (20mW∕cm2) in order to avoid nonlinear effects. Broad PL spectra were obtained, presenting a line-shape structure that can be reproduced by two superimposed peaks at around 780 and 950nm. We have observed that both PL intensity and line-shape change by varying the annealing as well as the implantation temperatures. Implantations performed at 400°C or higher produce a remarkable effect in the PL line shape, evidenced by a strong redshift, and a striking intensity increase of the peak located at the long-wavelength side of the PL spectrum. In addition we have studied the PL dependence on the excitation power density (from 0.002to15W∕cm2). The samples with broad NC size distribution containing large grains, as revealed by transmission electron microscopy observations presented a PL spectrum whose line shape was strongly dependent on the excitation power density. While high excitation power densities (saturation regime) induce only the short-wavelength part of the PL spectrum, low excitation power densities bring out the appearance of the hidden long-wavelength part of the emission. The present results are explained by current models.
Self-organization in protein folding and the hydrophobic interaction
Authors: Gerstman Bernard S. , Chapagain Prem P.
Published: August 2005

Self-organization is a critical aspect of living systems. During the folding of protein molecules, the hydrophobic interaction plays an important role in the collapse of the peptide chain to a compact shape. As the hydrophobic core tightens and excludes water, not only does the number of hydrophobic side chain contacts increase, but stabilization is further enhanced by an increase in strength of each hydrophobic interaction between side chains in the core. Thus, the self-organization of the protein folding process augments itself by enhancing the stability of the core against large-scale motions that would unfold the protein. Through calculations and computer simulations on a model four-helix bundle protein, we show how the strengthening of the hydrophobic interaction is crucial for stabilizing the core long enough for completion of the folding process and quantitatively manifests self-organizing dynamical behavior.
The coupled thermoelectroelastic behaviors of biphasic piezocomposites
Authors: Zhang Duan-Ming , Yang Feng-Xia , Zhong Zhi-Cheng , Wei Nian , Han Xiang-Yun , Li Zhi-Hua , Zhen Ke-Yu , Jiang Shenglin
Published: August 2005

A theoretical framework for effective thermoelectroelastic moduli is developed in terms of the Dunn-Taya theory and Dunn’s model. This theoretical framework provides a physical insight and reflects directly the contribution of each phase and the influence of interaction (or the coupling effect) between phases. The coupled thermoelectroelastic behaviors are discussed.
Structure of hard-sphere fluid and precursor structures to crystallization
Authors: O’Malley Brendan , Snook Ian
Published: August 2005

The structural origin of the commonly observed split second peak of the radial distribution function of a supercooled or glassy liquid is examined in this work using the hard-sphere fluid as an example. A novel approach to the analysis of the microscopic structure of a fluid is described, which permits the decomposition of both the radial distribution function and bond-angle distribution function of a system of particles into contributions from a small number of ring structures. The method uses a modified shortest-path definition of rings appropriate to the analysis of the medium-range structure of dense systems. It is shown that the split peak is an indicator of the emergence of precursor structures to crystal formation. The origin of the split peak provides a structural link between fluid and crystalline phases and our results suggest that it is neither a structural feature peculiar to glassy phases nor a smooth structural continuation of the stable-fluid phase. This structural feature of simple glassy systems is more appropriately described as a signifier of the frustration of emerging crystalline order in a fluid.
Effects of dust particles and layer properties on organic electronic devices fabricated by stamping
Authors: Cao Yifang , Kim Changsoon , Forrest Stephen R. , Soboyejo Wole
Published: August 2005

The mechanical properties of organic semiconductor thin films are determined using nanoindentation. The measured mechanical properties are incorporated into finite element simulations of deformation that arise during cathode patterning of organic electronic devices by pressure stamping methods. Simulations show that dust particles interposed between the stamp and film surface affect the evolution of contact areas when silicon or compliant polydimethyl-siloxane stamp dies are employed. We also examine the effects of the transferred metal layer thickness and stamp bulk modulus. Experimental and modeling results are found to be in good agreement. The implications of the results are discussed for the fabrication of a range of organic electronic devices.
An extended ab initio QM/MM MD approach to structure and dynamics of Zn(II) in aqueous solution
Authors: Fatmi M. Qaiser , Hofer Thomas S. , Randolf Bernhard R. , Rode Bernd M.
Published: August 2005

Structural and dynamical properties of Zn(II) in aqueous solution were investigated, based on an ab initio quantum mechanical/molecular mechanical (QM/MM) molecular dynamics simulation at double-ζ Hartree–Fock quantum mechanical level including the first and second hydration shells into the QM region. The inclusion of the second shell in the QM region resulted in significant changes in the properties of the hydrate. The first shell coordination number was found to be 6, the second shell consists of ∼14 water molecules. The structural properties were determined in terms of RDF, ADF, tilt and theta angle distributions, while dynamics were characterized by mean ligand residence times, ion-ligand stretching frequencies and the vibrational and librational motions of water ligands.
Thermal and solvent effects on the NMR and UV parameters of some bioreductive drugs
Authors: Ramalho Teodorico C. , Taft Carlton A.
Published: August 2005

N 15 NMR chemical shifts and n→π* electronic transition energy for metronidazole (1) has been calculated and compared with experimental data. A detailed computational study of 1 is presented, with special attention to the performance of various theoretical methods for reproducing spectroscopic parameters in solution. The most sophisticated approach involves density functional based on the Car-Parrinello molecular dynamics simulations of 1 in aqueous solution (BP86 level) and averaging chemical shifts and ΔE(n→π*) over snapshots from the trajectory. In the NMR and UV calculations for these snapshots (performed at the B3LYP level), a small number of discrete water molecules are retained, and the remaining bulk solution effects are included via a polarizable continuum model (PCM). A good agreement with experiment is also obtained using static geometry optimization and NMR computation of pristine 1 employing a PCM approach. Further theoretical predictions are also reported for O17 NMR and ΔE(n→π*) of three hydroxycinnamic acid derivatives, which suggest that it is essential to incorporate the dynamics and solvent effects for NMR and UV calculations in the condensed phase.
Faceting and structural anisotropy of nanopatterned CdO(110) layers
Authors: Zúñiga-Pérez J. , Martínez-Tomás C. , Muñoz-Sanjosé V. , Munuera C. , Ocal C. , Laügt M.
Published: August 2005

CdO(110) layers with a self-organized surface structure have been grown on (101¯0) sapphire (m plane) substrates by metal-organic vapor phase epitaxy. The epitaxial relationships between layer and substrate have been determined and a crystallographic model that accounts for the CdO in-plane orientation, which results in a reduced lattice mismatch when the CdO[001] direction is perpendicular to the sapphire c axis, has been proposed. Although the measured lattice parameters indicate that the layers are almost fully relaxed, an anisotropic mosaicity is detected with symmetrical rocking curves attaining minimum values when measured along the CdO[1¯10] direction. The layer morphology consists of a regular ridge-and-valley structure which defines, again, a preferential in-plane direction. The grooves run parallel to the CdO[001] axis and exhibit lateral surfaces sloped at 28° with respect to the (110) surface. The influence of growth temperature and VI∕II molar ratio on the anisotropic mosaicity and morphology has been analyzed.
Vibrational cooling in a cold ion trap: Vibrationally resolved photoelectron spectroscopy of cold C60− anions
Authors: Wang Xue-Bin , Woo Hin-Koon , Wang Lai-Sheng
Published: August 2005

We demonstrate vibrational cooling of anions via collisions with a background gas in an ion trap attached to a cryogenically controlled cold head (10–400 K). Photoelectron spectra of vibrationally cold C60− anions, produced by electrospray ionization and cooled in the cold ion trap, have been obtained. Relative to spectra taken at room temperature, vibrational hot bands are completely eliminated, yielding well-resolved vibrational structures and a more accurate electron affinity for neutral C60. The electron affinity of C60 is measured to be 2.683±0.008eV. The cold spectra reveal complicated vibrational structures for the transition to the C60 ground state due to the Jahn-Teller effect in the ground state of C60−. Vibrational excitations in the two Ag modes and eight Hg modes are observed, providing ideal data to assess the vibronic couplings in C60−
Control of specific domain structure in KNbO3 single crystals by differential vector poling method
Authors: Hirohashi Junji , Yamada Kazuhiro , Kamio Hiroyuki , Uchida Masao , Shichijyo Shiro
Published: August 2005

The controllability of specific domain structures in KNbO3 single crystals was investigated by electric poling to several different orientations at room temperature. By applying electric field to the direction corresponding to the differetial direction between the original and intended spontaneous polarization directions (differential vector poling method), 60°-, 90°-, and 180°-domain pairs were successfully fabricated under control in KNbO3. The measured threshold electric field for 90°-domain pairs was the lowest (140V∕mm), which could be related to the difference between the piezoelectric coefficients of the poling direction. For 60°- and 90°-domain pairs, theoretical uncharged domain walls fabricated under control without the generation of other domain structures. For 120°-domain pairs, (011)pc uncharged domain wall was not observed, which suggests the difficulty in generating uncharged 120°-domain walls without passing through the phase transition.
Study of the stabilization and recombination of nitrogen atoms in impurity–helium condensates
Authors: Boltnev R. E. , Krushinskaya I. N. , Pelmenev A. A. , Popov E. A. , Stolyarov D. Yu. , Khmelenko V. V.
Published: August 2005

The stabilization and recombination of nitrogen atoms N(4S) in nitrogen-helium and nitrogen–neon-helium condensates obtained by the injection of impurity particles from a gas discharge into bulk superfluid helium are investigated by the EPR method. It is established that the stabilized nitrogen atoms reside inside and on the surface of impurity clusters forming a porous structure in the bulk superfluid helium. The possibility of increasing the specific energy of impurity–helium condensates by increasing their density through mechanical pressing is investigated. For nitrogen-helium condensates an eightfold increase in the specific energy is achieved. The recombination loss of N(4S) upon heating of impurity–helium condensates in the temperature range 1.7–7 K is detected. This permits verification of the mechanism of thermoluminescence of impurity–helium condensates.
On the thermodynamics of quasi-two-dimensional electron gas
Authors: Gokhfeld V. M.
Published: August 2005

The equilibrium properties of an anisotropic electron system whose spectrum is characterized by open isoenergetic surfaces, typical of charge carriers in layered conducting crystals, are considered. The equation of state and other thermodynamic relations are obtained in explicit form; the differences from the thermodynamic properties of an ordinary electron gas are pointed out.
One-dimensional electron lattice system with a long-range interelectron repulsion on a disordered host lattice
Authors: Slutskin A. A. , Kovtun H. A.
Published: August 2005

We study what happens to a generalized Wigner crystal, GWC (a regular structure formed by narrow-band electrons on a one-dimensional periodic host lattice), when the host lattice suffers a random distortion that does not break its long-range order. We show that an arbitrarily weak distortion of this kind gives rise to soliton-like GWC defects (discrete solitons, DS) in the ground state, and thereby converts the ordered GWC into a new disordered macroscopic state—lattice Wigner glass (LWG). The ground-state DS concentration is found to be proportional to λ4 (λ is the typical host-lattice strain). We show that the low-temperature LWG thermodynamics and kinetics are fully described in DS terms. A new phenomenon of a super-slow logarithmic relaxation in the LWG is revealed. Its time turns out to be tens orders of magnitude greater than the microscopic ones. Analytical dependences of LWG thermodynamic quantities on temperature and λ are obtained for an arbitrary relationship between the relevant Coulomb energies and the electron bandwidth.
Shubnikov–de Haas oscillations, peaks, and different temperature regimes of the diagonal conductivity in the integer quantum Hall conductor
Authors: Gvozdikov V. M.
Published: August 2005

A theory for the Shubnikov–de Haas oscillations in the diagonal conductivity σxx of a 2D conductor is developed for the case when electron states within the broadened Landau levels are localized except for a narrow stripe in the center. The standard Shubnikov–de Haas oscillations take place only in the low-field region, which at higher magnetic fields crosses over into peaks. In the limit Ωτ≫1 peaks in the σxx became sharp and between them σxx→0 (Ω is the cyclotron frequency, τ is the electron scattering time). The conductivity peaks display different temperature behavior with the decrease of temperature T: a thermal activation regime, σxx∝exp(−Δ/T), which holds at higher temperatures, crosses over into the variable-range-hopping regime at lower temperatures with σxx∝1/Texp(−T0/T) (the prefactor 1/T is absent in the conductance).
Enstrophy dissipation in freely evolving two-dimensional turbulence
Authors: Tran Chuong V.
Published: August 2005

Freely decaying two-dimensional Navier-Stokes turbulence is studied. The conservation of vorticity by advective nonlinearities renders a class of Casimirs that decays under viscous effects. A rigorous constraint on the palinstrophy production by nonlinear transfer is derived, and an upper bound for the enstrophy dissipation is obtained. This bound depends only on the decaying Casimirs, thus allowing the enstrophy dissipation to be bounded from above in terms of initial data of the flows. An upper bound for the enstrophy dissipation wave number is derived and the new result is compared with the classical dissipation wave number.
Velocity slip in microscale cylindrical Couette flow: The Langmuir model
Authors: Myong R. S. , Reese J. M. , Barber R. W. , Emerson D. R.
Published: August 2005

The velocity slip on the solid surfaces of microscale cylindrical Couette flow is investigated using the Langmuir adsorption model for the gas-surface molecular interaction. The accommodation coefficient in the Maxwell model, which is a free parameter based on the concept of diffusive reflection, is replaced by a physical parameter of heat adsorption in the Langmuir model. The phenomenon of velocity inversion is then clearly explained by introducing a velocity polar on the hodograph plane. It is also shown that the quantity used to determine the momentum slip in a concentric cylindrical geometry should be based upon the angular velocity, not the velocity itself. Finally, and despite their totally independent considerations of the gas-surface molecular interaction, the Maxwell and Langmuir slip models are shown to be in qualitative agreement with direct simulation Monte Carlo data in capturing the general features of the flow field.
Temperature dependence of Raman scattering in hexagonal indium nitride films
Authors: Pu X. D. , Chen J. , Shen W. Z. , Ogawa H. , Guo Q. X.
Published: August 2005

We report on Raman spectroscopy study of hexagonal InN thin films grown by metal-organic vapor-phase epitaxy, with the emphasis on frequencies and linewidths of E2(high) and A1(LO) modes in the temperature range from 93to443K. The present InN exhibits a fundamental band gap of ∼1.2eV from photoluminescence and optical transmission spectra, which is in good agreement with the recent suggested parameter for intrinsic InN. The temperature dependence of the E2(high) and A1(LO) phonons can be described well by a model which has taken into account the contributions of the thermal expansion of the crystal lattice, the strain between InN thin films and sapphire substrates, as well as three- and four-phonon coupling. Micro-Raman mapping results also demonstrate the high uniformity of the studied InN.
On the resonances and polarizabilities of split ring resonators
Authors: García-García J. , Martín F. , Baena J. D. , Marqués R. , Jelinek L.
Published: August 2005

In this paper, the behavior at resonance of split ring resonators (SRRs) and other related topologies, such as the nonbianisotropic SRR and the broadside-coupled SRR, are studied. It is shown that these structures exhibit a fundamental resonant mode (the quasistatic resonance) and other higher-order modes which are related to dynamic processes. The excitation of these modes by means of a properly polarized time varying magnetic and/or electric fields is discussed on the basis of resonator symmetries. To verify the electromagnetic properties of these resonators, simulations based on resonance excitation by nonuniform and uniform external fields have been performed. Inspection of the currents at resonances, inferred from particle symmetries and full-wave electromagnetic simulations, allows us to predict the first-order dipolar moments induced at the different resonators and to develop a classification of the resonances based on this concept. The experimental data, obtained in SRR-loaded waveguides, are in agreement with the theory and point out the rich phenomenology associated with these planar resonant structures.
Coherent control of a flux qubit by phase-shifted resonant microwave pulses
Authors: Kutsuzawa Tatsuya , Tanaka Hirotaka , Saito Shiro , Nakano Hayato , Semba Kouichi , Takayanagi Hideaki
Published: August 2005

The quantum state of a flux qubit was successfully pulse controlled by using a resonant microwave. We observed Ramsey fringes by applying a pair of phase-shifted π∕2 microwave pulses without introducing detuning. With this method, the qubit state can be rotated on an arbitrary axis in the x-y plane of the Bloch sphere in a rotating frame. We successfully observed qubit Larmor precession stroboscopically with an angular velocity of 2π×11.4Grad∕s. In combination with Rabi pulses, this method enables us to achieve full control of single qubit rotation with shorter operation time.
Dieletric anomalies in Pb0.7(1−x)Ca0.7xLa0.2TiO3
Authors: Soon Hwee Ping , Wang John , Fu Desheng , Itoh Mitsuru
Published: August 2005

Transitions from ferroelectric to relaxorlike and then to quantum paraelectriclike behavior occur in Pb0.7(1−x)Ca0.7xLa0.2TiO3 (PCLT) with increasing x from 0.05 to 0.60. The relaxorlike behavior, which can be well fitted to the Vogel-Fulcher relation, is clearly demonstrated by the frequency dispersions of permittivity. More interestingly, a thermal hysteresis of ∼5K was observed in the temperature dependences of real and imaginary permittivity (ε′ and ε″) for PCLT with x=0.40 under both zero-field cooling and zero-field heating conditions. The compositional dependence of transition temperature Tmax vanished with a finite slope, contrary to that of the quantum ferroelectric relation Tmax∝(x−xc)0.5.
Open circuit voltage improvement of high-deposition-rate microcrystalline silicon solar cells by hot wire interface layers
Authors: Mai Y. , Klein S. , Carius R. , Stiebig H. , Geng X. , Finger F.
Published: August 2005

Significant improvement in open circuit voltage and fill factor was achieved for microcrystalline silicon (μc-Si:H) solar cells deposited by plasma-enhanced chemical vapor deposition (PECVD) by the incorporation of an intrinsic μc-Si:Hp∕i buffer layer fabricated by hot-wire (HW) CVD. The improved p∕i interface quality, likely due to the ion-free deposition on the p layers in the HWCVD process, was concluded from a considerably enhanced blue light response in such solar cells. Using this buffer layer concept allows the authors to apply high deposition rate PECVD processes for the μc-Si:Hi layer material, yielding a high efficiency of 10.3% for a single junction μc-Si:H solar cell.
Dielectric properties of epitaxial Ba0.5Sr0.5TiO3 films on amorphous SiO2 on sapphire
Authors: Li H. , Finder J. , Liang Y. , Gregory R. , Qin W.
Published: August 2005

The strain-relieved crystalline Ba0.5Sr0.5TiO3 (BST) film on SiO2∕Al2O3 was achieved by combining a molecular-beam epitaxy of BST on Si∕Al2O3 and a post-growth anneal in oxygen at elevated temperatures. The oxidation anneal not only converted the thin Si interlayer into amorphous SiO2 and eliminated the dielectric loss from the Si, but also relieved local strain in the film. The resulting BST film showed promising dielectric properties with 66% tunability and 0.016 dielectric loss, respectively. Additionally, temperature-dependent permittivity of the BST film resembled that of the bulk BST ceramics.
High resolution, high collection efficiency in numerical aperture increasing lens microscopy of individual quantum dots
Authors: Liu Zhiheng , Goldberg Bennett B. , Ippolito Stephen B. , Vamivakas Anthony N. , Ünlü M. Selim , Mirin Richard
Published: August 2005

We demonstrate the application of a subsurface solid immersion technique to the photoluminescence spectroscopy of individual quantum dots. Contrasted with the conventional solid immersion microscopy, we used a numerical aperture increasing lens and moved the interface between the sample and the solid immersion lens away from the focal plane, thus diminished the influence of interface artifacts on the images obtained in a two-dimensional scan. Meanwhile, our technique has achieved a high spatial resolution of λ∕3 that is capable of resolving the spectroscopic features of single QDs. We also demonstrate that the collection efficiency of our system is six times better than that of a conventional confocal microscope with a high NA objective.
Combined electromagnetic and photoreaction modeling of CLD-1 photobleaching in polymer microring resonators
Authors: Huang Yanyi , Poon Joyce K. S. , Liang Wei , Yariv Amnon , Zhang Cheng , Dalton Larry R.
Published: August 2005

By combining a solid-state photoreaction model with the modal solutions of an optical waveguide, we simulate the refractive index change due to the photobleaching of CLD-1 chromophores in an amorphous polycarbonate microring resonator. The simulation agrees well with experimental results. The photobleaching quantum efficiency of the CLD-1 chromophores is determined to be 0.65%. The combined modeling of the electromagnetic wave propagation and photoreaction precisely illustrates the spatial and temporal evolution of the optical properties of the polymer material as manifested in the refractive index and their effects on the modal and physical properties of the optical devices.
Caspase Inhibition Enhances Ischemic Tolerance of Fasciocutaneous Flaps
Authors: Sumer Baran D. , Gastman Brian R. , Gao Feng , Haughey Bruce H. , Paniello Randal C. , Nussenbaum Brian
Published: August 2005

Objectives/Hypothesis: To demonstrate the significance of apoptosis in ischemia‐reperfusion injury in revascularized fasciocutaneous flaps and test the hypothesis that pharmacologic inhibition of caspases prolongs the allowable primary ischemia time of these flaps.

Study Design: Animal study using the epigastric flap in adult male Sprague‐Dawley rats.

Methods: Fifty‐nine rats were treated with the caspase inhibitor (Q‐VD‐OPH) reconstituted in dimethylsulfoxide (DMSO) (n = 20, 8 mg/kg:0.8 mL/kg), DMSO alone (n = 19, 0.8 mL/kg), or saline (n = 20, 0.8 mL/kg). Treatment was given as a single intraperitoneal injection 30 minutes before starting primary ischemia. Epigastric flaps were subjected to increasing ischemia times followed by reperfusion. The flaps were harvested and analyzed 7 days later, and viability was assessed. Probit statistical analysis was used to determine the critical ischemia time. This was defined as the time point when 50% of the flaps in each group were expected to survive.

Results: The calculated critical ischemia times were 8.92 hours (95% confidence interval 7.19–10.47 h) for the saline group, 16.35 hours (95% confidence interval 11.82–19.89 h) for the DMSO group, and 21.73 hours (95% confidence interval 19.39–25.37 h) for the DMSO with Q‐VD‐OPH group. These differences were significantly different from each other.

Conclusions: Pretreatment of fasciocutaneous flaps with a free radical scavenger alone or in combination with a caspase inhibitor significantly increases the flap's tolerance of primary ischemia. The added benefit of the caspase inhibitor suggests that apoptosis plays an important role in ischemia‐reperfusion injury in soft tissue flaps.
Perioperative Parathyroid Hormone Assay for Diagnosis and Management of Postthyroidectomy Hypocalcemia
Authors: Scurry W Cooper , Beus Kirt S. , Hollenbeak Christopher S. , Stack Brendan C.
Published: August 2005

Objectives/Hypothesis: The purpose of this study was to assess the relationship between perioperative changes in parathyroid hormone (PTH) level and the likelihood of postthyroidectomy hypocalcemia.

Study Design: In a series of 78 patients undergoing total or completion thyroidectomy, PTH levels were measured before surgery and at 10 minutes after removal of the thyroid gland.

Methods: A prospective, nonrandomized collection of serum from 78 consecutive total or completion thyroidectomy procedures performed by a single surgeon was carried out over 18 months. Analysis is made of PTH levels, serum calcium values, need for calcium supplementation, and symptoms of hypocalcemia.

Results: Both a PTH change of 75% and an absolute postoperative PTH of 7 pg/mL are accurate standards for predicting symptomatic hypocalcemia after total or completion thyroid surgery.

Conclusions: Perioperative PTH levels are a tool for the prediction of postoperative symptomatic hypocalcemia after thyroidectomy. A PTH level drawn 10 minutes after removal of the thyroid predicts the likelihood of postoperative hypocalcemia.
Intranasal Lysine‐Aspirin in Aspirin‐Sensitive Nasal Polyposis: A Controlled Trial
Authors: Parikh Abhi A. , Scadding Glenis K.
Published: August 2005

Objectives/Hypothesis: Intranasal lysine‐aspirin has been used as a method of desensitization in patients with aspirin‐sensitive nasal polyps to control their recurrence and prevent frequent surgical intervention. However, the studies are limited in number, and their design is open to criticisms. Thus, we conducted a controlled trial to study the clinical effectiveness of topical lysine‐aspirin in patients with aspirin‐sensitive nasal polyposis.

Study Design: Prospective, randomized, double blind, placebo controlled, crossover trial.

Methods: Aspirin‐sensitive patients confirmed by intranasal challenge were enrolled and randomized to receive 16 mg of topical lysine‐aspirin every 48 hours or placebo for 6 months before crossover. Polyp growth and nasal and chest symptoms were monitored using acoustic rhinometry, nasal inspiratory peak flow, peak expiratory flow rate, and a daily diary of symptom scores.

Results: Twenty‐two patients were enrolled. After withdrawals and drop outs, data were available on 11 patients for analysis. Multivariate analysis of measured parameters did not reveal a significant clinical benefit to patients receiving topical lysine‐aspirin compared with placebo. Deterioration was similar while on lysine‐aspirin or placebo.

Conclusions: This is the first controlled clinical trial of topical desensitization in aspirin‐sensitive nasal polyp patients. Despite the failure to demonstrate clinical benefit, tissue studies have shown a significant improvement at the microscopic level.1 Further work with larger numbers of patients along with conventional treatment may show a clinical improvement in these patients.
Differential Penetration of Ototopicals and Water through Tympanostomy Tubes
Authors: Smith Lee P. , Smullen Jennifer L. , Younis Ramzi T.
Published: August 2005

Objective: To evaluate the penetration of ototopicals and water through tympanostomy tubes (TT) using a physical model.

Study Design: An in vitro model was created to measure the ability of various solutions to penetrate a variety of TT.

Methods: A TT was placed through a perforation (myringotomy) in a silastic sheet (tympanic membrane) fixed between the ends of two 1 mL syringes. Measurements were obtained of the maximum height various liquids (tap water, 2% soapy water, ocean water, ofloxacin otic, corticosporin otic, and ciprofloxacin/dexamethasone otic) achieved before penetrating different TTs (1.0 mm or 1.27 mm Paparella silicone, 1.14 mm or 1.27 mm Reuter Bobbin titanium, 1.27 mm Collar Button fluoroplastic or 1.14 mm T‐type silicone).

Results: Two percent soapy water was significantly more permeable than water and ocean water in all tubes studied. Ciprofloxacin/dexamethasone otic was significantly more permeable than tap water, ocean water, and ofloxacin otic in only the Collar Button fluoroplastic TT. Our results suggest that titanium TTs are more permeable than other TT. Otherwise, ototopicals, tap water, and ocean water behaved similarly across all TT studied.

Conclusions: Our results demonstrate that ototopicals, tap water, and ocean water behave similarly with regard to TT penetration. Ciprofloxacin/dexamethasone otic may have better penetration than other ototopicals. Titanium TT may be easier to penetrate than other TT.
Factors Affecting Cancer Recurrence after Microvascular Flap Reconstruction of the Head and Neck
Authors: Roostaeian Jason , Suh Jeffrey D. , Sercarz Joel A. , Abemayor Elliot , Lee Jivianne T. , Blackwell Keith E.
Published: August 2005

Objective: Our objective was to determine which factors are associated with cancer recurrence after microvascular reconstruction of the head and neck for squamous cell carcinoma (SCC).

Study Design: A cohort of patients who fit the inclusion/exclusion criteria were identified retrospectively.

Methods: A group of 184 patients who underwent successful surgical resection and simultaneous microvascular reconstruction of the head and neck for treatment of SCC were identified. The mean age was 60 (range 23–90) years, there were 115 males and 69 females, and mean follow‐up was 26.2 (range 1–99) months. Various factors were analyzed to determine whether they were associated with cancer recurrence, including those pertaining to 1) recipient vessel choice, 2) prior cancer treatment, and 3) cancer staging criteria. Statistical analysis was performed using SPSS statistical software.

Results: Overall cancer stage (P = .005), T stage (P = .0001), history of previous cancer treatment (P = .004), and history of previous chemotherapy (P = .044) were found to be statistically significant predictors of cancer recurrence on univariate analysis. However, on multivariate analysis, only T stage (P = .005) and history of previous cancer treatment (P = .008) remained as statistically significant predictors of cancer recurrence. Recipient vessel selection was not statistically associated with cancer recurrence.

Conclusions: In our study, only T stage and a history of previous cancer treatment were associated with increased cancer recurrence. Neither the recipient vessel chosen nor its location impacted cancer recurrence. This suggests that recipient vessel selection and preparation for microvascular reconstruction do not jeopardize the adequacy of oncologic resection and are therefore oncologically sound.
Methylation‐Associated Silencing of Death‐Associated Protein Kinase Gene in Laryngeal Squamous Cell Cancer
Authors: Kong Wei‐Jia , Zhang Song , Guo Changkai , Zhang Sulin , Wang Yanjun , Zhang Dan
Published: August 2005

Objectives/Hypothesis: Death‐associated protein kinase (DAPK) is a Ca2+/calmodulin‐regulated Ser/Thr kinase that functions as a positive mediator of programmed cell death. It has been found that DAPK gene is frequently inactivated by its promoter hypermethylation in some cancers and tumor cell lines. However, it is not clear whether promoter hypermethylation of DAPK gene exists in laryngeal squamous cell cancer (LSCC). The aim of this study was to investigate the promoter methylation status of the DAPK gene in LSCC and the effect of 5‐Aza‐2'‐deoxycytidine (5‐Aza‐CdR), a demethylating agent, on Hep‐2 cells, a human laryngeal cancer cell line, and on xenografts of Hep‐2.

Methods: Methylation‐specific polymerase chain reaction (PCR) and reverse‐transcription PCR techniques were used to determine the promoter methylation status and mRNA expression of DAPK gene in LSCC. Furthermore, Hep‐2 cells in vitro and in vivo were treated by 5‐Aza‐CdR to explore the effect of demethylating agents on DAPK mRNA expression and tumor growth.

Results: Hypermethylation of DAPK gene promoter was found in 39 (67.2%) of 58 LSCC samples. There was no significant difference in the promoter hypermethylation rate among the samples of different histologic grades or samples from patients with different T stages. However, there was significant difference in methylation status of DAPK gene between the samples from patients in N0 stages and those from patients in N1 stages. No promoter hypermethylation of DAPK gene was found in any of the five normal laryngeal tissue samples. DAPK mRNA expression was not detected in tumor specimens with promoter hypermethylation. On the contrary, DAPK mRNA expression was observed in the unmethylated tumor specimens, specimens from tissues adjacent to the tumor, and normal laryngeal tissues samples. Promoter hypermethylation of DAPK gene was found, and no DAPK mRNA expression was detected in Hep‐2 cells. DAPK mRNA expression in Hep‐2 cells and xenografts could be restored by treating cells and xenografts with 5‐Aza‐CdR. The tumors' xenografts, induced by way of Hep‐2 cell injection in nude mice treated with 5‐Aza‐CdR, were obviously smaller than those in nude mice treated with phosphate‐buffered saline.

Conclusions: Abnormal loss of DAPK expression could be associated with aberrant promoter region methylation in the LSCC. 5‐Aza‐CdR may slow the growth of Hep‐2 cells in vitro and in vivo by reactivating tumor suppressor gene DAPK silenced by de novo methylation.
Vestibular‐Evoked Myogenic Potentials in Infancy and Early Childhood
Authors: Sheykholesami Kianoush , Kaga Kimitaka , Megerian Cliff A. , Arnold James E.
Published: August 2005

Objective: Hearing impairment and the often concurrent loss of vestibular function, which is rarely assessed in infants, can both impair sensory integration critical to the development of normal motor coordination. This study demonstrates, for the first time, that vestibular function in infants can be noninvasively assessed using vestibular‐evoked myogenic potentials (VEMPs). Our intentions were to demonstrate that VEMPs can be reliably recorded from neonates and to compare neonatal VEMPs with those obtained from normal adults.

Study Design: Prospective cohort study.

Methods: Myogenic evoked potentials induced by air‐ and bone‐conducted auditory stimuli were recorded from the sternocleidomastoid muscles of 12 normal neonates and 12 neonates with various clinical findings. These included infants with bilateral atresia of the external auditory canals, Treacher‐Collins syndrome, and neonates who failed universal neonatal screening.

Results: With the exception of one patient with hearing loss, reproducible biphasic VEMPs were recorded from the sternocleidomastoid muscle of all the infants using loud, short tone‐burst sounds.

Conclusions: The VEMP has characteristics that differentiate it from the postauricular response and the Jaw reflex. The VEMPs were dominant on the side ipsilateral to the stimulated ear. The overall morphology of the neonatal VEMP is quite similar to that of adults. The major neonatal differences are a shorter latency of the n23 peak and higher amplitude variability. Our results suggest that recording of the VEMP in neonates with various audio‐vestibular problems provides useful information about vestibular function in this population and may provide information that leads to better care and rehabilitation for neonates at risk of developmental and motor system delay.
A Model for Cochlear Implant Electrode Insertion and Force Evaluation: Results with a New Electrode Design and Insertion Technique
Authors: Roland J Thomas
Published: August 2005

Objectives and Hypothesis: This study has the specific aim of evaluating the insertion characteristics of a new cochlear implant electrode. Techniques for evaluation of fluoroscopic real time mechanical insertion dynamics, histologic electrode position and trauma results, hydraulic force, and mechanical insertion forces are presented. In addition, this study should serve to present a novel model for cochlear implant electrode insertion evaluations.

Study Design: Prospective analysis using a series of analytical techniques.

Methods: All studies are conducted in fixed cadaveric temporal bones. Real time fluoroscopic insertion evaluations, histologic evaluations for trauma and electrode position in embedded bones, hydraulic measures, and mechanical intracochlear force measurements are conducted with a current and new electrode.

Results: The Contour Advance electrode provides a more reliable and less traumatic insertion when deployed with the Advance Off Stylet technique. This is largely because of a reduction in intracochlear outer wall force generation. Fluoroscopic and histologic analysis reveal a smooth insertion without reliance on cochlear outer wall contact. No hydraulic forces were detected when measured from the superior semicircular canal ampulla.

Conclusion: The model used for this study provides valuable information to cochlear implant surgeons and design engineers. The Contour Advance electrode, inserted with the Advance Off Stylet technique, represents an improvement over the Contour electrode inserted with the standard insertion technique.
Thyroplasty Type I With Montgomery Implant among Native French Language Speakers with Unilateral Laryngeal Nerve Paralysis
Authors: Laccourreye Ollivier , El Sharkawy Louay , Holsinger F Christopher , Hans Stéphane , Ménard Madeleine , Brasnu Daniel
Published: August 2005

Objective:To document the long‐term results achieved with the Montgomery implant in 96 French speakers with a unilateral laryngeal nerve paralysis (ULNP).

Study Design:Retrospective series, inception cohort of 96 patients.

Methods:Data regarding morbidity and functional results were obtained at regular visits to our clinic. All patients were followed for a minimum of 6 months or until death. Forty‐two patients had a minimum of 12 months of follow‐up. Early in the study, 36 patients were prospectively recorded under similar conditions before placement of the Montgomery implant and at 1, 3, 6, and 12 months postoperatively.

Results:None of the 96 patients died in the immediate postoperative period. The perioperative course was unremarkable in 94.8% of cases. Perioperative problems included failure to obtain a satisfactory phonatory result in three patients, difficulty to stabilize the implant posteriorly in one patient, and fracture of the inferior rim of the thyroid cartilage window in another patient. The primary immediate postoperative problem (within the first postoperative month) was laryngeal dyspnea, noted in four patients. According to the patient's subjective assessment, speech and voice was always improved in the immediate postoperative period. However, three patients had secondary degradation of speech and voice. Revision surgery under local anesthesia resulted in a 97.9% ultimate speech and voice success rate. According to the patient's subjective assessment, adequate swallowing in the immediate postoperative period was achieved in 94.2% of cases that had swallowing problems preoperatively. A significant statistical increase in the duration parameters (phonation time, phrase grouping, speech rate) together with a statistical significant decrease in both the jitter and shimmer values was noted when comparing the preoperative and the postoperative values at 1 month. Analysis of the evolution of the speech and voice parameters at 1, 3, 6, and 12 months postoperatively showed a significant decrease in the fundamental frequency and noise‐to‐harmonic ratio values but did not demonstrate any significant differences for the other speech and voice parameters.

Conclusions:From the reported data, we conclude that the type I thyroplasty with Montgomery implant insertion is a safe and reproducible method to treat ULNP. Furthermore, this system achieves very good and stable phonatory results. Finally, the use of this technique and implant system appears safe in patients from various cultures with ULNP from a variety of causes and severe comorbidity. Over the past decade at our department, this procedure progressively replaced the use of the intracordal injection of autologous fat injection that was initially advocated in patients with ULNP.
Human Papillomavirus (HPV) Transcripts in Malignant Inverted Papilloma are from Integrated HPV DNA
Authors: McKay Shawn P. , Grégoire Lucie , Lonardo Fulvio , Reidy Patrick , Mathog Robert H. , Lancaster Wayne D.
Published: August 2005

Objectives: The objectives of the study were to detect human papillomavirus (HPV) sequences in nasal inverted papilloma (IP) lesions and to determine whether HPV is involved in the progression of IP to sinonasal squamous cell carcinoma (SCC).

Study Design: A retrospective study was performed on 14 patients diagnosed with IP within the last 12 years. Three of these 14 patients developed SCC.

Methods: Eighteen formalin‐fixed, paraffin‐embedded tissue blocks were obtained for these 14 patients. After DNA extraction, polymerase chain reaction (PCR) was performed, followed by hybridization using HPV 6, 11, 16, 18, 31, 33, 35, 45, and 52 specific DNA probes, in an attempt to identify HPV type in each specimen. After RNA extraction, the integration status of the HPV genome was evaluated based on the relative abundance of E7 and E5 viral transcripts, assessed by quantitative real‐time PCR.

Results: HPV sequences were detected in samples from 3 of the 14 patients with IP. Of the three patients with SCC, HPV sequences were detected in two patients, whereas one patient was negative for the oligoprobes tested. Of the 11 patients diagnosed only with IP, 1 patient was positive for HPV DNA (HPV type 11). This difference in HPV positivity between IP and SCC was not statistically significant (P = .09, Fisher's Exact test, two tailed). Viral transcripts were detected in both patients with SSC who were HPV positive. Because HPV early transcripts are polycistronic, loss of 3′ transcript sequences (E5) and retention of 5′ sequences (E7) indicates integration. One of the SSC containing HPV 18 sequences showed a E7/E5 ratio of 776:1. The other SSC showed E7 transcripts and an absence of E5 transcripts

Conclusion: HPV transcripts were present in SCC positive for HPV, and the relative level of E7 to E5 transcripts indicates integration of the viral genome. These findings are suggestive of HPV having an active role in the lesion. More extensive studies are needed to determine the exact role of HPV in IP and progression to SCC.