bluuebunny/crossref_metadata_2025 huggingface dataset:
A finite element method for the probabilistic creep of solids
Authors: Delph T. J. , Yukich J. E.
Published: November 2005

We outline here a finite element technique for the creep of solids whose constitutive equation contains one or more random parameters. In contrast to other finite element techniques for the prediction of random structural response, the present method is based upon exact relations from the theory of probability. It yields, at a given value of time, the probability density function for the field variable of interest, e.g. stress or displacement components. The method is illustrated by a simple creeping beam problem, using a power‐law creep constitutive equation. The calculated distributions are found to be highly skewed, and in excellent agreement with the results of Monte Carlo simulation.
Finite element dispersion analysis for the three‐dimensional second‐order scalar wave equation
Authors: Abboud Najib N. , Pinsky Peter M.
Published: November 2005

The dispersive properties of finite element semidiscretizations of the three‐dimensional second‐order scalar wave equation are examined for both plane and spherical waves. This analysis throws light on the performance and limitations of the finite element approximation over the entire spectrum of wavenumbers and provides guidance for optimal mesh discretization as well as mass representation. The 8‐node trilinear element, 20‐node serendipity element, 27‐node triquadratic element and the linear and quadratic spherically symmetric elements are considered.
Elastoplastic analysis using the 14‐node brick element family
Authors: Smith I. M. , Kidger D. J.
Published: November 2005

Typical brick‐based finite elements in current use are the 8‐and 20‐node members of the serendipity group. For displacement analyses of solids the 8‐node element can be quite stiff in certain deformation modes, while the 20‐node element can be quite expensive to use, involving as it does 60 degrees of freedom and a fairly high order of quadrature to avoid spurious eigenmodes of the element stiffness. In this paper a family of intermediate 14‐node elements is investigated. Derivation of their properties can be considerably assisted by computer algebra. Performance is evaluated for elastic and elastoplastic problems.
Computational model for 3‐D contact problems with friction based on the penalty method
Authors: Perić Djordje , Owen D. R. J.
Published: November 2005

A model based on the penalty method for 3‐D contact problems with friction is proposed. The friction forces are assumed to follow the Coulomb law, with a slip criterion treated in the context of a standard return mapping algorithm. Consistent linearization of the field equations is performed which leads to a fully implicit scheme with non‐symmetric tangent stiffness which preserves asymptotic quadratic convergence of the Newton‐Raphson method. Numerical results are obtained for some representative examples and compared with existing solutions.
Preconditioning techniques for non‐symmetric matrices with application to temperature calculations of cooled concrete
Authors: Van Der Ploeg Auke
Published: November 2005

Preconditioning techniques based on incomplete LU‐decomposition are described for large, sparse, non‐symmetric matrix systems in which the largest part of the coefficient matrix is a symmetric M‐matrix with a very regular sparsity pattern. Some methods are described in which a small part of the matrix with an irregular sparsity pattern is treated very efficiently. The methods are combined with CGSTAB and tested on a non‐stationary diffusion problem in three dimensions. For this type of problems the modified incomplete decomposition as suggested by Gustafsson performs significantly better than the standard incomplete factorization.

Also some methods are described to construct preconditioners for large, sparse, non‐symmetric matrices with arbitrary sparsity patterns. Methods in which the sparsity pattern of the preconditioning matrix is based on a drop tolerance are very effective and relatively cheap.
Solutions to shape and topology eigenvalue optimization problems using a homogenization method
Authors: Díaaz Alejandro R. , Kikuchi Noboru
Published: November 2005

A solution strategy to find the shape and topology of structures that maximize a natural frequency is presented. The methodology is based on a homogenization method and the representation of the shape of the structure as a material property. The problem is formulated as a reinforcement problem in which a given structure is reinforced using a prescribed amount of material. Two dimensional, plane elasticity problems are considered. Examples are presented for illustration.
Partial mixed 3‐D element for the analysis of thick laminated composite structures
Authors: Liao Chung‐Li , Tsai J.‐ S.
Published: November 2005

For the analysis of thick laminated composite structures this paper proposes a partial mixed 3‐D element. The variational principle of this new element is obtained by modifying the Hellinger–Reissner principle. The functional of the present stationary principle is constructed by treating three displacements (u, v, w) and two transverse shear stresses (τxz, τyz) as independent of each other. Hence the nodal variables of the present mixed element contain three displacements and two transverse shear stresses. The other stresses (σx, σy, τxy, σz) are computed from the assumed displacement field and nodal displacement field and nodal displacements. The present element can satisfy the requirements of (1)transverse shear stress continuity between laminate layers and (2)boundary conditions of free transverse shear stresses on the top and bottom surfaces. These requirements are violated by conventional displacement finite elements. Since the stiffness matrix of the present element is formulated by combining a displacement model and a mixed model, it is definite, rather than indefinite as for the conventional mixed elements. Also, these two transverse shear stresses are part of the solution variables and are solved directly together with displacements. Examples are presented to demonstrate the accuracy and efficiency of this proposed partial mixed 3‐D element in the analysis of thick laminated composite structures.
A time integration algorithm for elasto‐viscoplastic cubic crystals applied to modelling polycrystalline deformation
Authors: Maniatty A. M. , Dawson P. R. , Lee Y. ‐S.
Published: November 2005

An algorithm for integrating the constitutive equations for an elasto‐viscoplastic cubic crystal is presented which is shown to be easily employed in a polycrystalliné analysis. Anisotropic elastic behaviour is incorporated into the standard constitutive equations for ductile single crystals. The algorithm is shown to be efficient, robust and general. The primary advantage of this algorithm is that is provides an implicit integration of the plastic deformation gradient while including the elastic response. This permits taking large time steps while maintaining accuracy and stability. Several polycrystalline examples are presented to demonstrate the effect of the time step on the solution. Examples also are presented which compare the algorithm described herein to an algorithm which neglects the elastic part of the deformation. In addition, the effect of the anisotropic component of the elasticity is investigated by comparing the results with those obtained assuming isotropic elasticity.
Use of ‘simple solutions’ for boundary integral methods in elasticity and fracture analysis
Authors: Lutz Earlin , Ingraffea Anthony R. , Gray Leonard J.
Published: November 2005

The 'simple solutions' or 'indirect' method of analysing Cauchy and hypersingular integrands in the gradient (flux or traction) boundary integral equation (BIE) is applied to linear elastic fracture analysis. Because of the geometric singularity of the crack surface, application of the simple solutions formulas on the crack face requires integration over a temporary 'closure surface' rather than the remainder of the body. Closure surface constructions are exhibited for crack surfaces, allowing the gradient BIE to be applied as a constraint equation on a crack surface where the primary BIE is degenerate. Computational results are given for two benchmark fracture problems.
A consistent co‐rotational formulation for shells using the constant stress/constant moment triangle
Authors: Peng X. , Crisfield M. A.
Published: November 2005

The simplest facet‐shell formulation involves the combination of the constant‐strain membrane triangle with a constant‐curvature bending triangle. The paper describes a technique whereby this facet‐formulation is extended to handle geometric non‐linearity by means of a co‐rotational procedure. Emphasis is placed on the derivation of a technique that is increment‐independent with both the internal force vector and tangent stiffness matrix being derived from the 'total strain measures' in a 'consistent manner'. Numerical examples are presented which demonstrate an excellent numerical performance.
Effect of cross‐sectional warping of anisotropic sandwich laminates due to dynamic loads using a refined theory and C° finite elements
Authors: Mallikarjuna  , Kant T.
Published: November 2005

An attempt has been made to study the effect of cross‐sectional warping in the symmetrically laminated anisotropic composite sandwich plates for transient loads. A higher‐order shear deformation theory (HOST) is used in conjunction with the simple displacement based C° finite element method (FEM). As is well‐known, the classical first‐order theories hitherto considered were inadequate to describe the propagation of waves in the highly orthotropic sandwich laminates. The present theory, which is more accurate than the Reissner‐Mindlin theory, is applied herein, for the evaluation of plate response to different types of dynamic loads. An explicit central difference scheme is employed for the integration of dynamic equations of equilibrium with a diagonalized mass matrix obtained by a special procedure applicable to quadrilateral isoparametric elements. The numerical results of the present investigation have been compared with the first‐order shear deformation theory (FOST) and the differences between HOST and FOST are examined. The results presented here should be useful in obtaining better correlation between theory and experiment, and to numerical analysts in verifying their results.
An infinite boundary element formulation for three‐dimensional potential problems
Authors: Kaljević Igor , Saigal Sunil , Ali Ashraf
Published: November 2005

An infinite boundary element (IBE) is presented for the analysis of three‐dimensional potential problems in an unbounded medium. The IBE formulations are done to allow their coupling with the finite element (FE) matrices for finite domains and to obtain the overall matrices without destroying the banded structure of the FE matrices. The infinite body is divided into a number of zones whose contributions are expressed in terms of the nodal quantities at FE nodes by employing suitable decay functions and performing mainly analytical integrations of the boundary element kernels. The continuity and compatibility conditions for the potential and the flux at the FE‐IBE interface are developed. The relationships for the contributions of the IBE flux vectors to the FE load vectors are given. The final equations for the IBE are obtained in the usual FE stiffness‐load vector form and are easily assembled with the FE matrices for the finite object. A series of numerical examples in heat transfer and electromagnetics were solved and compared with alternative solutions to demonstrate the validity of the present formulations.
Ionic liquids as novel solvents and catalysts for the direct polycondensation of N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐phenylalanine diacid with various aromatic diamines
Authors: Mallakpour Shadpour , Kowsari Elaheh
Published: November 2005

Ionic liquids (ILs) are often considered green solvents capable of replacing traditional organic solvents and have been extensively studied in materials chemistry and catalysis. In this study, the direct polycondensation of N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐phenylalanine diacid with various aromatic diamines was performed in IL media. The influence of various reaction parameters, including the nature of the IL cations and anions, the monomer structures, the reaction temperature, and the reaction time, on the yields and inherent viscosities of the resulting optically active poly(amide imide)s (PAIs) were investigated. Direct polycondensation successfully preceded in ILs and triphenyl phosphite (a condensing agent) without any additional extra components, such as LiCl and pyridine, which are used in similar reactions in ordinary molecular solvents. Therefore, ILs can act as both solvents and catalysts. Various high‐molecular‐weight, optically active PAIs were obtained in high yields with inherent viscosities ranging from 0.54 to 0.88 dL/g. This method was also compared with three other classical methods for the polycondensation of the aforementioned monomers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6545–6553, 2005
Amphiphilic star‐block copolymers based on a hyperbranched core: Synthesis and supramolecular self‐assembly
Authors: Jia Zhifeng , Zhou Yongfeng , Yan Deyue
Published: November 2005

Novel amphiphilic star‐block copolymers, star poly(caprolactone)‐block‐poly[(2‐dimethylamino)ethyl methacrylate] and poly(caprolactone)‐block‐poly(methacrylic acid), with hyperbranched poly(2‐hydroxyethyl methacrylate) (PHEMA–OH) as a core moiety were synthesized and characterized. The star‐block copolymers were prepared by a combination of ring‐opening polymerization and atom transfer radical polymerization (ATRP). First, hyperbranched PHEMA–OH with 18 hydroxyl end groups on average was used as an initiator for the ring‐opening polymerization of ε‐caprolactone to produce PHEMA–PCL star homopolymers [PHEMA = poly(2‐hydroxyethyl methacrylate); PCL = poly(caprolactone)]. Next, the hydroxyl end groups of PHEMA–PCL were converted to 2‐bromoesters, and this gave rise to macroinitiator PHEMA–PCL–Br for ATRP. Then, 2‐dimethylaminoethyl methacrylate or tert‐butyl methacrylate was polymerized from the macroinitiators, and this afforded the star‐block copolymers PHEMA–PCL–PDMA [PDMA = poly(2‐dimethylaminoethyl methacrylate)] and PHEMA–PCL–PtBMA [PtBMA = poly(tert‐butyl methacrylate)]. Characterization by gel permeation chromatography and nuclear magnetic resonance confirmed the expected molecular structure. The hydrolysis of tert‐butyl ester groups of the poly(tert‐butyl methacrylate) blocks gave the star‐block copolymer PHEMA–PCL–PMAA [PMAA = poly(methacrylic acid)]. These amphiphilic star‐block copolymers could self‐assemble into spherical micelles, as characterized by dynamic light scattering and transmission electron microscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6534–6544, 2005
Block polymethacrylonitrile copolymers based on a central polyether or polyacetal block: A study of the salt/copolymer complexes
Authors: Saunier J. , Alloin F.
Published: November 2005

Some block copolymers based on polymethacrylonitrile (PMAN) and polyethers or polyacetals were synthesized in an anionic way. To appreciate the salt/polymer interactions, polymer electrolytes were prepared by the dissolution of lithium imide or lithium perchlorate in PMAN homopolymer and copolymers. The investigation of the triblock copolymer complexes allowed the solvating competition between nitrile‐ and ether‐ or acetal‐functional groups to be highlighted. The polydioxolane solvating ability was equivalent to that of PMAN but lower than that of polyoxyethylene or polyoxypropylene. Moreover, we were interested in the salt effect as block compatibilization was concerned. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3665–3673, 2005
A natural 15N approach to determine the biological fixation of atmospheric nitrogen by biological soil crusts of the Negev Desert
Authors: Russow Rolf , Veste Maik , Böhme Frank
Published: November 2005

Biological soil crusts are important cryptogamic communities covering the sand dunes of the north‐western Negev. The biological crusts contain cyanobacteria and other free‐living N2‐fixing bacteria and are hence able to fix atmospheric nitrogen (N). This is why they are considered to be one of the main N input pathways into the desert ecosystem. However, up to now, in situ determinations of the N2 fixation in the field are not known to have been carried out. We examined the natural 15N method to determine the biological N2 fixation by these soil crusts under field conditions. This novel natural 15N method uses the lichen Squamarina with symbiotic green algae—which are unable to fix N2—as a reference in order to determine N2 fixation. Depending on the sampling location and year, the relative biological fixation of atmospheric nitrogen was estimated at 84–91% of the total N content of the biological soil crust. The cyanobacteria‐containing soil lichen Collema had a fixation rate of about 88%. These fixation rates were used to derive an absolute atmospheric N input of 10–41 kg N ha−1 year−1. These values are reasonable results for the fixation of atmospheric N2 by the biological crusts and cyanolichens and are in agreement with other comparable lab investigations. As far as we are aware, the results presented are the first to have been obtained from in situ field measurements, albeit only one location of the Negev with a small number of samples was investigated. Copyright © 2005 John Wiley & Sons, Ltd.
Theoretical study of the surface excitation parameter from reflection‐electron‐energy‐loss spectra
Authors: Pauly N. , Tougaard S. , Yubero F.
Published: November 2005

A theoretical method to determine the so‐called surface excitation parameter (SEP) is presented. This method is based on the modelling of reflection‐electron‐energy‐loss spectroscopy and more particularly on the analysis of energy‐differential inelastic electron scattering cross sections calculated within the model. The SEP is extracted from theoretical cross‐section spectrum by calculating the ratio between the surface loss component of the spectrum and the elastic peak intensity. The calculations have been performed entirely with the dielectric function, using the software QUEELS (Quantitative analysis of Electron Energy Losses at Surfaces) recently developed by Yubero and Tougaard [Surf. Interface Anal. 2004; 36: 824]. The angular distribution of SEP is calculated for angles between 10° and about 70° for aluminium and silicon. We propose also an extension of the method for materials (e.g. copper) that do not present clear surface and volume plasmons. Copyright © 2005 John Wiley & Sons, Ltd.
Zimmermann-Laband Syndrome in an Infant with an Atypical Histologic Finding
Authors: Atabek Mehmet Emre , Pirgon Ozgur , Sert Ahmet , Toy Hatice
Published: November 2005

Zimmermann-Laband syndrome is an inherited disorder that is characterized by abnormalities of the head, face, hands, and feet. Most children with this disorder have generalized hypertrichosis, large gingivae, and hypoplasia of the fingernails and toenails. We report a male infant who exhibited typical features of Zimmermann-Laband syndrome with an unusual histopathologic finding. Excised tissue from the infant's gingivae showed papillary projections that were composed of hyperplastic stratified squamous epithelium with different amounts of keratinization.
Optical biosensor provides insights for bradykinin B2receptor signaling in A431 cells
Authors: Fang Ye , Li Guangshan (Gary) , Peng Jinlin
Published: November 2005

The spatial and temporal targeting of proteins or protein assemblies to appropriate sites is crucial to regulate the specificity and efficiency of protein–protein interactions, thus dictating the timing and intensity of cell signaling and responses. The resultant dynamic mass redistribution could be manifested by label free optical biosensor, and lead to a novel and functional optical signature for studying cell signaling. Here we applied this technology, termed as mass redistribution cell assay technology (MRCAT), to study the signaling networks of bradykinin B2receptor in A431 cells. Using MRCAT, the spatial and temporal relocation of proteins and protein assemblies mediated by bradykinin was quantitatively monitored in microplate format and in live cells. The saturability to bradykinin, together with the specific and dose‐dependent inhibition by a B2specific antagonist HOE140, suggested that the optical signature is a direct result of B2receptor activation. The sensitivity of the optical signature to cholesterol depletion by methyl‐β‐cyclodextrin argued that B2receptor signaling is dependent on the integrity of lipid rafts; disruption of these microdomains hinders the B2signaling. Modulations of several important intracellular targets with specific inhibitors suggested that B2receptor activation results in signaling via at least dual pathways – Gs‐ and Gq‐mediated signaling. Remarkably, the two signaling pathways counter‐regulate each other. Several critical downstream targets including protein kinase C, protein kinase A, and epidermal growth factor receptor had been identified to involve in B2signaling. The roles of endocytosis and cytoskeleton modulation in B2signaling were also demonstrated.
Topo IIα reporter mice reveal proliferative regions in the epidermis and small intestine
Authors: Li Elizabeth R. , Watt Fiona M.
Published: November 2005

We investigated topoisomerase IIα promoter activity in epithelia. In confluent human keratinocytes the promoter (−557 to +90 bp) was upregulated by oncogenic Ras. In transgenic mice expressing GFP via the promoter, GFP expression in undamaged epidermis was confined to growing hair follicles. GFP was also expressed in intestinal crypts. GFP expression was upregulated in epidermis following wounding or phorbol ester treatment. In each situation GFP expression correlated with high endogenous topoisomerase IIα expression and high proliferation. The mice therefore provide a useful model for non‐invasive imaging of regions of high proliferation in normal or damaged epidermis.
Platelet‐activating factor induces matrix metalloproteinase‐9 expression through Ca2+‐ or PI3K‐dependent signaling pathway in a human vascular endothelial cell line
Authors: Ko Hyun-Mi , Kang Jee-Hae , Choi Jung-Hwa , Park Sung Jun , Bai Suk , Im Suhn-Young
Published: November 2005

Platelet‐activating factor (PAF) augments angiogenesis by promoting the synthesis of a variety of angiogenic factors, via the nuclear factor (NF)‐κB activation. Recently, we reported that PAF upregulates MMP‐9 expression in a NF‐κB‐dependent manner. In this study, we investigated the signaling pathway involved in PAF‐induced MMP‐9 expression in ECV304 cells. Our current data indicate that the Ca2+‐ or phosphatidylinositol 3‐kinase (PI3K)‐dependent signaling pathway is necessary for PAF‐induced MMP‐9 expression. Furthermore, PAF‐induced NF‐κB activation was blocked by selective inhibitors of Ca2+, PI3K, or extracellular signal‐regulated kinase (ERK). Our results suggest that PAF‐induced MMP‐9 expression, in a NF‐κB‐dependent manner, is regulated by Ca2+, PI3K and ERK signaling pathways.
The cell cycle regulator p27Kip1 interacts with MCM7, a DNA replication licensing factor, to inhibit initiation of DNA replication
Authors: Nallamshetty Shriram , Crook Martin , Boehm Manfred , Yoshimoto Takanobu , Olive Michelle , Nabel Elizabeth G.
Published: November 2005

The G1/S phase restriction point is a critical checkpoint that interfaces between the cell cycle regulatory machinery and DNA replicator proteins. Here, we report a novel function for the cyclin‐dependent kinase inhibitor p27Kip1 in inhibiting DNA replication through its interaction with MCM7, a DNA replication protein that is essential for initiation of DNA replication and maintenance of genomic integrity. We find that p27Kip1 binds the conserved minichromosome maintenance (MCM) domain of MCM7. The proteins interact endogenously in vivo in a growth factor‐dependent manner, such that the carboxyl terminal domain of p27Kip1 inhibits DNA replication independent of its function as a cyclin‐dependent kinase inhibitor. This novel function of p27Kip1 may prevent inappropriate initiation of DNA replication prior to S phase.
2‐Arachidonoylglycerol, an endogenous cannabinoid receptor ligand, enhances the adhesion of HL‐60 cells differentiated into macrophage‐like cells and human peripheral blood monocytes
Authors: Gokoh Maiko , Kishimoto Seishi , Oka Saori , Metani Yasuchika , Sugiura Takayuki
Published: November 2005

2‐Arachidonoylglycerol (2‐AG), an endogenous cannabionoid receptor (CB1 and CB2) ligand, enhanced the adhesion of HL‐60 cells differentiated into macrophage‐like cells to fibronectin and the vascular cell adhesion molecule‐1. The CB2 receptor, Gi/Go, intracellular free Ca2+ and phosphatidylinositol 3‐kinase were shown to be involved in 2‐AG‐induced augmented cell adhesion. 2‐AG also enhanced the adhesion of human monocytic leukemia U937 cells and peripheral blood monocytes. These results strongly suggest that 2‐AG plays some essential role in inflammatory reactions and immune responses by inducing robust adhesion to extracellular matrix proteins and adhesion molecules in several types of inflammatory cells and immune‐competent cells.
Steps toward recovery of function after hemilabyrinthectomy in frogs
Authors: Dieringer Norbert , Straka Hans
Published: November 2005

Removal of the labyrinthine organs on one side results in a number of severe postural and dynamic reflex deficits. Over time some of these behavioral deficits normalize again. At a chronic stage the brain of frogs exhibits a number of changes in vestibular and propriospinal circuits on the operated side that were studied in vitro. The onset of changes in the vestibular nuclear complex was delayed, became evident only after head posture had recovered by more than 50%, and was independent of the presence or absence of a degeneration of vestibular nerve afferent fibers. The time course of changes measured in the isolated spinal cord paralleled the time course of normalization of head and body posture. Results obtained after selective lesions of individual labyrinthine nerve branches show that unilateral inactivation of utricular afferent inputs is a necessary and sufficient condition to provoke postural deficits and propriospinal changes similar to those after the removal of all labyrinthine organs. The presence of multiple synaptic changes at distributed anatomic sites over different periods of time suggests that different parts of the central nervous system are involved in the normalization of different manifestations of the vestibular lesion syndrome. (Otolaryngol Head Neck Surg 1998;119:27–33.)
Brain‐derived neurotrophic factor gene therapy prevents spiral ganglion degeneration after hair cell loss
Authors: Staecker Hinrich , Gabaizadeh Ramin , Federoff Howard , Water Thomas R. Van De
Published: November 2005

Destruction of auditory hair cells results in the secondary degeneration of auditory neurons. This is because of the loss of neurotrophic factor support from the auditory hair cells, namely neurotrophin 3, which is normally produced by the inner hair cells. Both in vitro and in vivo studies have shown that delivery of either neurotrophin 3 or brain‐derived neurotrophic factor to these neurons can replace the trophic support supplied by the hair cells and prevent their degeneration. To prevent the degeneration of auditory neurons that occurs after neomycin destruction of the auditory hair cells we used a replication defective herpes simplex‐1 vector (HSVbdnflac) to transfect the gene for brain‐derived neurotrophic factor into the damaged spiral ganglion. Four weeks after the HSVbdnflac therapy we were able to detect stable functional production of brain‐derived neurotrophic factor that supported the survival of auditory neurons and prevented the loss of these neurons because of trophic factor deprivation‐induced apoptosis. (Otolaryngol Head Neck Surg 1998;119:7–13.)
Incidence of Deep Venous Thrombosis and Pulmonary Embolism in Otolaryngology‐Head and Neck Surgery
Authors: Moreano Edwin H. , Hutchison Joseph L. , McCulloch Timothy M. , Graham Scott M. , Funk Gerry F. , Hoffman Henry T.
Published: November 2005

OBJECTIVE

Postoperative deep venous thrombosis and pulmonary embolus are major causes of morbidity and mortality in patients undergoing surgical procedures. In contrast to other surgical fields, the incidence of these life‐threatening conditions has not been studied in our specialty. The purposes of this study were to elucidate the incidence of deep venous thrombosis and pulmonary embolus in patients after otolaryngologic operations and to identify specific risk factors that may contribute to the development of these conditions.

METHODS

A retrospective analysis was done of 12,805 total operations on adults done by the Department of Otolaryngology at our institution from January 1987 to December 1994 to determine the number of patients in whom postoperative deep venous thrombosis and pulmonary embolus developed. Patients in whom a postoperative thromboembolic event developed after an otolaryngologic surgical procedure were identified by the medical records department with use of an abstracting database. This search cross‐referenced disease‐specific codes for otolaryngologic procedures with the codes for deep venous thrombosis and pulmonary embolus to identify the 34 patients in this report. Results (rounded to the nearest decimal point) were then categorized according to the different sub‐specialties within otolaryngology, and appropriate statistical analysis tests were performed on the resulting data.

RESULTS

Thirty‐four patients with postoperative deep vein thrombosis were identified during the study period, for an overall incidence of 0.3%. Of these 34 patients, 24 also had a pulmonary embolus for an overall incidence of 0.2%. The incidence of deep venous thrombosis (and pulmonary embolus) in the subspecialties was as follows: head and neck surgery, 0.6% (0.4%); otology/neurotology, 0.3% (0.2%); head and neck trauma and plastic surgery, 0.1% (0.1%); and general otolaryngology, 0.1% (0.04%). Only the patient's age and the presence or absence of pneumatic compression devices were identified as independent risk factors for the development of a thromboembolic event.

CONCLUSIONS

Postoperative pulmonary embolus is a rare occurrence in the field of otolaryngology‐head and neck surgery. When it does occur, it causes significant morbidity and increases the cost of care for that patient. We discuss our approach to categorizing patients into low‐, intermediate‐, and high‐risk groups, as well as prophylaxis against pulmonary embolus. (Otolaryngol Head Neck Surg 1998;118:777‐84.)
A New Dosage Regimen for Topical Application of Ciprofloxacin in the Management of Chronic Suppurative Otitis Media
Authors: Aslan Asim , Altuntas Ali , Titiz Ali , Arda Hasan Nedim , Nalca Yildirim
Published: November 2005

The clinical and bacteriologic efficacy of topically applied ciprofloxacin was studied in 60 patients with chronic suppurative otitis media. Two hundred fifty and 125 μg/ml concentrations of ciprofloxacin solutions were given to two groups of patients. The duration of therapy was determined according to the clinical cure at follow‐up. More than 21 days of therapy was not needed in any patient. The clinical cure rate with 250 μg/ml ciprofloxacin was 78.1% at 14 days and with 125 μg/ml it was 83.3%. However, a 100% clinical cure rate and complete bacteriologic eradication was obtained in 21 days in both groups. In each group only one patient had otomycosis by the fourteenth day of therapy, although ear discharge had ceased. It was concluded that 125 μg/ml ciprofloxacin could be applied as successfully as 250 μg/ml, and the duration of therapy had to be at least 14 days. This new dosage regimen can be adopted as an optimal dosage for ototopical application of ciprofloxacin in chronic suppurative otitis media. It will also obviously decrease the expense of therapy. (Otolaryngol Head Neck Surg 1998;118:883–5.)
A Rare Case of Nasal Glioma in Adult Age
Authors: PASQUINI ERNESTO , FARNETI GIOVANNI , GIAUSA GIUSEPPE , BIAVATI MANUELA
Published: November 2005

Congenital midline nasal masses are rare lesions, occurring once in every 20,000 to 40,000 live births.1 – 3 Of these, nasal encephalocele, glioma, and dermoid cysts are the most common and have a potential intracranial extension.2 – 4 The exact incidence of nasal glioma is not well known, but to our knowledge a total of 164 cases have been reported in the literature to date.
Relevant issues in revision canal‐wall‐down mastoidectomy
Authors: Harvey Steven A. , Fox Mary C.
Published: November 2005

The role of canal‐wall‐down (CWD) versus intactcanal‐wall (ICW) mastoidectomy in the treatment of chronic otitis media with or without cholesteatoma remains a debated issue. Although past conventional wisdom has held that CWD mastoid surgery leads to a “safe” ear and is technically less demanding than the more controversial ICW mastoidectomy, this is often not the case. Although our preference is an ICW technique when possible, 47 of 109 (43%) mastoid procedures for chronic otitis media performed between January 1993 and June 1996 involved a CWD mastoid cavity. More than two thirds of these procedures (32 of 47) represented revision surgery, the most common indication being a poorly contoured, preexisting CWD mastoidectomy with persistent otorrhea. A dry, well‐epithelialized ear was obtained in 90% of cases. Our preferred method of ossicular reconstruction (double cartilage block ossiculoplasty) is detailed, and hearing results according to American Academy of Otolaryngology‐Head and Neck Surgery guidelines are reported.
Tinnitus severity, loudness, and depression
Authors: Folmer Robert L. , Griest Susan E. , Meikle Mary B. , Martin William H.
Published: November 2005

Answers to questionnaires filled out by 436 patients who visited our tinnitus clinic were analyzed. Patients were asked to report the presence or absence of depression and to rate the loudness and severity of their tinnitus. Responses to questions about tinnitus loudness and severity from 121 patients who reported current depression were compared with responses from 285 patients who reported no history of depression. There was no significant difference in reported loudness of tinnitus between patients with and without depression. However, patients with current depression scored significantly higher than patients without depression on all 12 questions relating to tinnitus severity. We conclude that depression and tinnitus severity are linked in some patients. Treatment of depression with medications and psychotherapy is likely to reduce tinnitus severity for many of these patients.
First Place—Resident Basic Science Award 1998: Role of Membrane Type 1‐Matrix Metalloproteinase and Gelatinase a in Head and Neck Squamous Cell Carcinoma Invasion in Vitro
Authors: Rosenthal Eben L. , Hotary Kevin , Bradford Carol , Weiss Stephen J.
Published: November 2005

The proteolytic activity of gelatinase A, a member of the matrix metalloproteinase (MMP) family, is considered to be a critical factor in tumor cell penetration of the extracellular matrix. To express catalytic activity, however, gelatinase A requires activation by another MMP, membrane type 1‐matrix metalloproteinase (MT1‐MMP). The head and neck squamous cell carcinoma cell line, UM‐SCC‐1, forms a quiescent monolayer atop collagen unless stimulated with epidermal growth factor (EGF; 3.5 nmol/L), which induces single cell invasion within 48 hours. To determine the role of the MT1‐MMP/gelatinase A protease system in an in vitro stromal invasion model, expression vectors for MT1‐MMP and gelatinase A were transfected into UM‐SCC‐1 (SCC‐1/MT and SCC‐1/gelA, respectively). SCC‐1/MT tumor cells were found to invade in the absence of growth factor stimulation. Additionally, these cells displayed shorter onset to invasion and penetrated deeper into the collagen gel with EGF stimulation than did control vector transfectants. SCC‐1/gelA cells similarly demonstrated invasion in the absence of EGF and a heightened invasive potential under EGF‐stimulated conditions. These results suggest that the MT1‐MMP/gelatinase A protease system participates in squamous cell carcinoma invasion of collagenous matrices. (Otolaryngol Head Neck Surg 1999;121:337‐43.)
Assessment of Plate Use for Mandibular Reconstruction: Has Changing Technology Made a Difference?
Authors: Klotch Douglas W. , Gal Thomas J. , Gal Robin L.
Published: November 2005

Reconstruction of mandibular defects with a variety of alloplastic materials during a 22‐year period was reviewed. Outcomes were examined to determine whether specific plating technology affected the incidence of plate‐related complications including plate exposure, plate fracture, and plate removal. Repair with the miniplate, reconstruction plate, titanium hollow screw reconstruction plate, and locking reconstruction plate was evaluated. Although the incidence of plate fractures has decreased, there was no significant change in the rate of plate exposure. Recurrent disease was noted to be a significant contributing factor in the development of plate‐related complications.
Behavioral Model of Chronic Tinnitus in Rats
Authors: Bauer Carol A. , Brozoski Thomas J. , Rojas Raul , Boley Jeremy , Wyder Melanie
Published: November 2005

An animal model of tinnitus was developed to study chronic salicylate‐induced tinnitus in rats. Novel features of the model included oral dosing of salicylate, test stimuli that included a range of pure tones and silence, and assessment of tinnitus for several months. Experimental subjects were given sodium salicylate in their drinking water while control subjects received normal tap water. Subjects were conditioned to press a lever for food in the presence of continuous white noise. At random intervals, offset of the noise was paired with a noxious stimulus, resulting in cessation of lever pressing during the silent test periods. At other randomly scheduled intervals, a test tone was substituted for the white noise, unpaired with noxious stimuli. When the test stimuli were pure tones, the salicylate‐treated subjects suppressed less than the control subjects. One explanation for this result is that the experimental subjects' sensations of tones were noisier than those of the controls because experimental subjects were experiencing tinnitus.
Magnetic Resonance Sialography
Authors: Jungehülsing Markus , Fischbach Roman , Schröder Ursula , Kugel Harald , Damm Michael , Eckel Hans Edmund
Published: November 2005

To evaluate a new noninvasive sialographic technique, we applied a new magnetic resonance technique to 10 healthy volunteers and 21 patients with lesions of the parotid gland. In addition to the usually performed T1 and T2 cross‐sectional sequences, a heavily T2‐weighted sequence (TR = 3600 msec, TE = 800 msec) was performed that allowed depiction of the fluid‐filled parotid duct system. Twenty‐one patients with benign as well as malignant parotid gland pathologies were examined: sialadenitis (n = 6), sicca syndrome (n = 2), pleomorphic adenoma (n = 4), carcinoma of the parotid gland (n = 2), lymphoepithelial carcinoma (n = 1), cystadenolymphoma (n = 3), non‐Hodgkin's lymphoma (n = 2), and congenital duct dilatation (n = 1). Stensen's duct was reliably depicted in all volunteers and patients. The primary branching ducts were reliably depicted in all normal cases. Intraglandular and extraglandular duct dilatations and duct strictures were well depicted in patients with chronic sialadenitis. Sialolithiasis with a calculus obstructing the duct was demonstrated in 2 cases. In conclusion, Initial experience indicates that magnetic resonance sialography can be applied successfully to investigate the duct system of the parotid gland. The usually performed cross‐sectional MRI (T1‐ and T2‐weighted images, gadolinium‐DTPA) depicts the internal architecture of the parotid gland with high reliability. Magnetic resonance sialography with heavily T2‐weighted images adds important information about the ductal system. Because it is completely noninvasive, the only contraindications are the ones generally accepted for MRI.
Comparison of the Effectiveness of Levofloxacin and Amoxicillin‐Clavulanate for the Treatment of Acute Sinusitis in Adults
Authors: Adelglass Jeffrey , Deabate C. Andrew , McElvaine Phillip , Fowler Cynthia L. , Lococco John , Campbell Theresa
Published: November 2005

In this comparative trial, outpatients with acute sinusitis were randomly assigned to receive levofloxacin (500 mg orally once daily) or amoxicillin‐clavulanate (500/125 mg orally 3 times daily) for 10 to 14 days. The success rates (cured and improved) 2 to 5 days after the end of treatment were 88.4% for the 267 clinically evaluable patients who received levofloxacin and 87.3% for the 268 clinically evaluable patients who received amoxicillin‐clavulanate. Drug‐related adverse events occurred in a smaller percentage of patients in the levofloxacin treatment group (7.4%) than in the amoxicillin‐clavulanate treatment group (21.2%). The most common of these were nausea, diarrhea, vaginitis, and abdominal pain for levofloxacin‐treated patients and diarrhea, vaginitis, nausea, genital moniliasis, abdominal pain, vomiting, and flatulence for amoxicillin‐clavulanate‐treated patients. The results of this study show that once‐daily administration of levofloxacin is as effective and better tolerated than amoxicillin‐clavulanate administered 3 times daily for treating acute sinusitis in adult outpatients.
Is Parental Perception an Accurate Predictor of Childhood Hearing Loss? A Prospective Study
Authors: Stewart Michael G. , Ohlms Laurie A. , Friedman Ellen M. , Sulek Marce , Duncan Newton O. , Fernandez Alberto D. , Bautista Marilyn H.
Published: November 2005

OBJECTIVE

We performed this study to assess whether parental perception of hearing loss predicted the results of audiometric testing in children with recurrent otitis media or persistent otitis media with effusion.

METHODS

As part of a larger prospective observational outcomes study of children undergoing tympanostomy tube placement, the child's parent completed a standardized questionnaire before and after tube placement. In addition, patients underwent age‐appropriate audiologic threshold and tympanometry testing before and after tube placement.

RESULTS

We enrolled 113 patients (median age, 2 years), and 93 (82%) completed follow‐up. Before treatment, parental perception of hearing loss did not predict hearing threshold level. After tube placement, parental perception of hearing loss was also poorly correlated with change in threshold.

CONCLUSIONS

Parental perception of their child's hearing loss is a poor predictor of objective audiologic findings both before and after treatment with tympanostomy tubes. These findings have important implications concerning the importance of screening for hearing loss in children with otitis media with effusion.
Hydroxyapatite Canal Wall Reconstruction/Mastoid Obliteration
Authors: Estrem Scott Allen , Highfill Gary
Published: November 2005

The controversy regarding removal of the posterior external canal wall during mastoid surgery spans many decades. There are inherent advantages and disadvantages to either removing or not removing the canal wall. The operation must be tailored to the patient and his or her unique situation. We describe our experience with external canal wall reconstruction and mastoid obliteration with hydroxyapatite in an effort to derive the best of both philosophies. Hydroxyapatite has been used in 3 different forms including granules, a preformed canal wall prosthesis, and with a block of hydroxyapatite sculpted to fit the individual defect. A total of 36 patients with up to 54‐month follow‐up are reported. Details of the techniques used, with advantages and pitfalls, are described.
Surgical Modification of the Difficult Mastoid Cavity
Authors: Dornhoffer John L.
Published: November 2005

This retrospective study used a computerized otologic database to identify patients undergoing revision surgery for a draining cavity unresponsive to medical therapy, with at least a 2‐year follow‐up. The surgical intervention involved partial mastoid obliteration and restoration of the middle ear space by use of cartilage reconstruction of the tympanic membrane. Ossicular reconstruction was achieved with either a partial or total ossicular replacement prosthesis. Because this technique involved contouring the mastoid cavity, the problems that usually occur, such as drainage or debris collection, were alleviated. In addition, re‐establishment of the middle ear space often restored hearing. A completely dry cavity was achieved in 18 of 20 patients. An overall statistically significant improvement in hearing (P < 0.05) was obtained, with the mean pure‐tone average air‐bone gap decreasing to 16.1 dB from 36.5 dB. This technique has proven to be a useful adjunct in the surgical management of the chronically draining cavity.
Behaviors of Bulbar Respiratory Interneurons during Fictive Swallowing and Vomiting
Authors: Nakazawa Ken , Umezaki Toshiro , Zheng Yu , Miller Alan D.
Published: November 2005

Behaviors of the same individual medullary respiratory interneurons were examined during both swallowing and vomiting. In 8 decerebrated and paralyzed cats, 18 neurons having either augmenting expiratory (E‐AUG), decrementing expiratory (E‐DEC), decrementing inspiratory (I‐DEC), or constant inspiratory (I‐CON) firing patterns were recorded near the most rostral part of the nucleus ambiguus. All neurons exhibited elementary reflexes to single‐shock stimulation of the superior laryngeal nerve. During fictive swallowing elicited by superior laryngeal nerve stimulation, all neurons were basically inactive. During fictive vomiting induced by vagal stimulation and/or emetic drugs, all E‐AUG and E‐DEC neurons tested either were silent or fired weakly between successive retches, whereas I‐DEC and I‐CON neurons tested exhibited burst activity during the retching and early‐expulsion phases. These results indicate that these bulbar respiratory neurons, which may be involved in respiratory rhythmogenesis, are multifunctional neurons that could also be involved in vomiting but not likely in swallowing.
Two Faces of Orbital Hematoma in Intranasal (Endoscopic) Sinus Surgery
Authors: Stankiewicz James A. , Chow James M.
Published: November 2005

Orbital hematoma and blindness can occur during or after sinus surgery. All orbital hematomas in 3500 endoscopic sinus ethmoidectomies were identified and evaluated for type, treatment, and sequelae. Fifteen orbital hematomas were identified, with 1 case of temporary blindness and no cases of permanent blindness. Two types of orbital hematoma were identified—slow (venous) and fast (arterial)—which differ in management. The venous type results from penetration of the lamina papyracea and disruption of veins. The arterial hematoma is caused by anterior or posterior ethmoid artery injury. The treatment approach to each is different, with blindness more likely occurring from a fast (arterial) hematoma. Of the 2 types of orbital hematoma that can occur during sinus surgery, surgical decompression and hemorrhage control are more likely with the fast arterial hematoma, which has not been the subject of any prior presentation. Cause and management of each will be discussed.