bluuebunny/crossref_metadata_2025 huggingface dataset:
The Dynamics of Cardiac Fibrillation
Authors: Weiss James N. , Qu Zhilin , Chen Peng-Sheng , Lin Shien-Fong , Karagueuzian Hrayr S. , Hayashi Hideki , Garfinkel Alan , Karma Alain
Published: August 2005

Reentry occurs when the electrical wave propagating through the atria or ventricles breaks locally and forms a rotor (also called a scroll wave or functional reentry). If the waves propagating outward from a rotor develop additional wavebreaks (which may form new rotors), fibrillation results. Tissue heterogeneity, exacerbated by electrical and structural remodeling from cardiac disease, has traditionally been considered the major factor promoting wavebreak and its degeneration to fibrillation. Recently, however, dynamic factors have also been recognized to play a key role. Dynamic factors refer to cellular properties of the cardiac action potential and Ca
i
cycling, which dynamically generate wave instability and wavebreak, even in tissue that is initially completely homogeneous. Although the latter situation can only be created in computer simulations, its relevance to real (heterogeneous) cardiac tissue has been unequivocally demonstrated. Dynamic factors are related to membrane voltage (V
m
) and Ca
i
. V
m
factors include electrical restitution of action potential duration and conduction velocity, short-term cardiac memory, and electrotonic currents. Ca
i
factors are related to dynamic Ca
i
cycling properties. They act synergistically, as well as with tissue heterogeneity, to promote wavebreak and fibrillation. As global properties, rather than local electrophysiological characteristics, dynamic factors represent an attractive target for novel therapies to prevent ventricular fibrillation.
Endothelial β
3
-Adrenoreceptors Mediate Nitric Oxide–Dependent Vasorelaxation of Coronary Microvessels in Response to the Third-Generation β-Blocker Nebivolol
Authors: Dessy Chantal , Saliez Julie , Ghisdal Philippe , Daneau Géraldine , Lobysheva Irina I. , Frérart Françoise , Belge Catharina , Jnaoui Karima , Noirhomme Philippe , Feron Olivier , Balligand Jean-Luc
Published: August 2005

Background—

The therapeutic effects of nonspecific β-blockers are limited by vasoconstriction, thus justifying the interest in molecules with ancillary vasodilating properties. Nebivolol is a selective β
1
-adrenoreceptor antagonist that releases nitric oxide (NO) through incompletely characterized mechanisms. We identified endothelial β
3
-adrenoreceptors in human coronary microarteries that mediate endothelium- and NO-dependent relaxation and hypothesized that nebivolol activates these β
3
-adrenoreceptors.

Methods and Results—

Nebivolol dose-dependently relaxed rodent coronary resistance microarteries studied by videomicroscopy (10 μmol/L, −86±6% of prostaglandin F2α contraction); this was sensitive to NO synthase (NOS) inhibition, unaffected by the β
1-2
-blocker nadolol, and prevented by the β
1-2-3
-blocker bupranolol (
P
<0.05; n=3 to 8). Importantly, nebivolol failed to relax microarteries from β
3
-adrenoreceptor–deficient mice. Nebivolol (10 μmol/L) also relaxed human coronary microvessels (−71±5% of KCl contraction); this was dependent on a functional endothelium and NO synthase but insensitive to β
1-2
-blockade (all
P
<0.05). In a mouse aortic ring assay of neoangiogenesis, nebivolol induced neocapillary tube formation in rings from wild-type but not β
3
-adrenoreceptor– or endothelial NOS–deficient mice. In cultured endothelial cells, 10 μmol/L nebivolol increased NO release by 200% as measured by electron paramagnetic spin trapping, which was also reversed by NOS inhibition. In parallel, endothelial NOS was dephosphorylated on threonine
495
, and fura-2 calcium fluorescence increased by 91.8±23.7%; this effect was unaffected by β
1-2
-blockade but abrogated by β
1-2-3
-blockade (all
P
<0.05).

Conclusions—

Nebivolol dilates human and rodent coronary resistance microarteries through an agonist effect on endothelial β
3
-adrenoreceptors to release NO and promote neoangiogenesis. These properties may prove particularly beneficial for the treatment of ischemic and cardiac failure diseases through preservation of coronary reserve.
CCL2
Polymorphisms Are Associated With Serum Monocyte Chemoattractant Protein-1 Levels and Myocardial Infarction in the Framingham Heart Study
Authors: McDermott David H. , Yang Qiong , Kathiresan Sekar , Cupples L. Adrienne , Massaro Joseph M. , Keaney John F. , Larson Martin G. , Vasan Ramachandran S. , Hirschhorn Joel N. , O’Donnell Christopher J. , Murphy Philip M. , Benjamin Emelia J.
Published: August 2005

Background—

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine strongly implicated in promoting atherosclerosis in animal models, but human genetic evidence is contradictory.

Methods and Results—

We analyzed the association of genetic variation in the MCP-1 gene (
CCL2
) with prevalent myocardial infarction and serum MCP-1 levels in the community-based Framingham Heart Study Offspring Cohort (50% women; mean age, 62 years). MCP-1 levels and
CCL2
genotypes were determined in 3236 and 1797 individuals, respectively. Significant clinical correlates of MCP-1 levels were age, cigarette smoking, triglycerides, body mass index, and waist-to-hip ratio. The
MCP-1-2578G
allele located in the
CCL2
regulatory region was significantly associated with both higher serum MCP-1 levels in a recessive genetic model (358±10 versus 328±3 pg/mL;
P
=0.002) and higher prevalence of myocardial infarction in a dominant genetic model (adjusted odds ratio, 2.0; 95% CI, 1.2 to 3.3;
P
=0.005). We also defined the linkage disequilibrium structure at the
CCL2
locus and observed 6 common haplotypes in whites. We performed haplotype-based association analysis and found that only the most frequent haplotype, defined by the
MCP-1-2578G
allele, was associated with prevalent MI.

Conclusions—

Our data are consistent with the hypothesis that MCP-1 is involved in the pathogenesis of human atherosclerosis and myocardial infarction.
Optimization via Intermittency with a Self-Organizing Neural Network
Authors: Kwok Terence , Smith Kate A.
Published: August 2005

One of the major obstacles in using neural networks to solve combinatorial optimization problems is the convergence toward one of the many local minima instead of the global minima. In this letter, we propose a technique that enables a self-organizing neural network to escape from local minima by virtue of the intermittency phenomenon. It gives rise to novel search dynamics that allow the system to visit multiple global minima as meta-stable states. Numerical experiments performed suggest that the phenomenon is a combined effect of Kohonen-type competitive learning and the iterated softmax function operating near bifurcation. The resultant intermittent search exhibits fractal characteristics when the optimization performance is at its peak in the form of 1/f signals in the time evolution of the cost, as well as power law distributions in the meta-stable solution states. The N-Queens problem is used as an example to illustrate the meta-stable convergence process that sequentially generates, in a single run, 92 solutions to the 8-Queens problem and 4024 solutions to the 17-Queens problem.
What Can a Neuron Learn with Spike-Timing-Dependent Plasticity?
Authors: Legenstein Robert , Naeger Christian , Maass Wolfgang
Published: August 2005

Spiking neurons are very flexible computational modules, which can implement with different values of their adjustable synaptic parameters an enormous variety of different transformations F from input spike trains to output spike trains. We examine in this letter the question to what extent a spiking neuron with biologically realistic models for dynamic synapses can be taught via spike-timing-dependent plasticity (STDP) to implement a given transformation F. We consider a supervised learning paradigm where during training, the output of the neuron is clamped to the target signal (teacher forcing). The well-known perceptron convergence theorem asserts the convergence of a simple supervised learning algorithm for drastically simplified neuron models (McCulloch-Pitts neurons). We show that in contrast to the perceptron convergence theorem, no theoretical guarantee can be given for the convergence of STDP with teacher forcing that holds for arbitrary input spike patterns. On the other hand, we prove that average case versions of the perceptron convergence theorem hold for STDP in the case of uncorrelated and correlated Poisson input spike trains and simple models for spiking neurons. For a wide class of cross-correlation functions of the input spike trains, the resulting necessary and sufficient condition can be formulated in terms of linear separability, analogously as the well-known condition of learnability by perceptrons. However, the linear separability criterion has to be applied here to the columns of the correlation matrix of the Poisson input. We demonstrate through extensive computer simulations that the theoretically predicted convergence of STDP with teacher forcing also holds for more realistic models for neurons, dynamic synapses, and more general input distributions. In addition, we show through computer simulations that these positive learning results hold not only for the common interpretation of STDP, where STDP changes the weights of synapses, but also for a more realistic interpretation suggested by experimental data where STDP modulates the initial release probability of dynamic synapses.
Geometrical Properties of Nu Support Vector Machines with Different Norms
Authors: Ikeda Kazushi , Murata Noboru
Published: August 2005

By employing the L1 or L∞ norms in maximizing margins, support vector machines (SVMs) result in a linear programming problem that requires a lower computational load compared to SVMs with the L2 norm. However, how the change of norm affects the generalization ability of SVMs has not been clarified so far except for numerical experiments. In this letter, the geometrical meaning of SVMs with the Lp norm is investigated, and the SVM solutions are shown to have rather little dependency on p.
Stimulus Competition by Inhibitory Interference
Authors: Tiesinga Paul H. E.
Published: August 2005

When two stimuli are present in the receptive field of a V4 neuron, the firing rate response is between the weakest and strongest response elicited by each of the stimuli when presented alone (Reynolds, Chelazzi, & Desimone, 1999). When attention is directed toward the stimulus eliciting the strongest response (the preferred stimulus), the response to the pair is increased, whereas the response decreases when attention is directed to the other stimulus (the poor stimulus). When attention is directed to either of the two stimuli presented alone, the firing rate remains the same or increases slightly, but the coherence between the neuron's spike train and the local field potential can increase (Fries, Reynolds, Rorie, & Desimone, 2001). These experimental results were reproduced in a model of a V4 neuron under the assumption that attention modulates the activity of local interneuron networks. The V4 model neuron received stimulus-specific excitation from V2 and synchronous inhibitory inputs from two local interneuron networks in V4. Each interneuron network was driven by stimulus-specific excitatory inputs from V2 and was modulated by the activity of the frontal eye fields. Stimulus competition was present because of a delay in arrival time of synchronous volleys from each interneuron network. For small delays, the firing rate was close to the rate elicited by the preferred stimulus alone, whereas for larger delays, it approached the firing rate of the poor stimulus. When either stimulus was presented alone, the neuron's response was not altered by the change in delay, but could change due to modulation of the degree of synchrony of the corresponding interneuron network. The model suggests that top-down attention biases the competition between V2 columns for control of V4 neurons primarily by changing the relative timing of inhibition, whereas changes in the degree of synchrony of interneuron networks modulate the response to a single stimulus. The new mechanism proposed here for attentional modulation of firing rate, gain modulation by inhibitory interference, is likely to have more general applicability to cortical information processing.
Mixture Modeling with Pairwise, Instance-Level Class Constraints
Authors: Zhao Qi , Miller David J.
Published: August 2005

The goal of semisupervised clustering/mixture modeling is to learn the underlying groups comprising a given data set when there is also some form of instance-level supervision available, usually in the form of labels or pairwise sample constraints. Most prior work with constraints assumes the number of classes is known, with each learned cluster assumed to be a class and, hence, subject to the given class constraints. When the number of classes is unknown or when the one-cluster-per-class assumption is not valid, the use of constraints may actually be deleterious to learning the ground-truth data groups. We address this by (1) allowing allocation of multiple mixture components to individual classes and (2) estimating both the number of components and the number of classes. We also address new class discovery, with components void of constraints treated as putative unknown classes. For both real-world and synthetic data, our method is shown to accurately estimate the number of classes and to give favorable comparison with the recent approach of Shental, Bar-Hillel, Hertz, and Weinshall (2003).
How Membrane Properties Shape the Discharge of Motoneurons: A Detailed Analytical Study
Authors: Meunier Claude , Borejsza Karol
Published: August 2005

Electrophysiological experiments and modeling studies have shown that after hyperpolarization regulates the discharge of lumbar motoneurons in anesthetized cats and is an important determinant of their firing properties. However, it is still unclear how firing properties depend on slow after hyperpolarization, input conductance, and the fast currents responsible for spike generation. We study a single-compartment integrate-andfire model with a slow potassium conductance that exponentially decays between spikes. We show that this model is analytically solvable, and we investigate how passive and active membrane properties control the discharge. We show that the model exhibits three distinct firing ranges (primary, secondary, and high frequency), and we explain the origin of these three ranges. Explicit expressions are established for the gain of the steady-state current-frequency (I− f) curve in the primary range and for the gain of the I− f curve for the first interspike interval. They show how the gain is controlled by the maximal conductance and the kinetic parameters of the after hyperpolarization conductance. The gain also depends on the spike voltage threshold, and we compute how it is decreased by threshold accommodation (i.e., the increase of the threshold with the injected current). In contrast, the gain is not very sensitive to the input conductance. This implies that tonic synaptic activity shifts the current-frequency curve in its primary range, in agreement with experiments. Taking into account the absolute refractory period associated with spikes somewhat reduces the gain in the primary range. More importantly, it accounts for the approximately linear and steep secondary range observed in many motoneurons. In the nonphysiological high-frequency range, the behavior of the I− f curve is determined by the fast voltage-dependent currents, via the amplitude of the fast repolarization afterspike, the duration of the refractory period, and voltage threshold accommodation, if present.
An Extended Analytic Expression for the Membrane Potential Distribution of Conductance-Based Synaptic Noise
Authors: Rudolph M. , Destexhe A.
Published: August 2005

Synaptically generated subthreshold membrane potential (Vm) fluctuations can be characterized within the framework of stochastic calculus. It is possible to obtain analytic expressions for the steady-state Vm distribution, even in the case of conductance-based synaptic currents. However, as we show here, the analytic expressions obtained may substantially deviate from numerical solutions if the stochastic membrane equations are solved exclusively based on expectation values of differentials of the stochastic variables, hence neglecting the spectral properties of the underlying stochastic processes. We suggest a simple solution that corrects these deviations, leading to extended analytic expressions of the Vm distribution valid for a parameter regime that covers several orders of magnitude around physiologically realistic values. These extended expressions should enable finer characterization of the stochasticity of synaptic currents by analyzing experimentally recorded Vm distributions and may be applicable to other classes of stochastic processes as well.
'In the Mirror of the Dance': A Lucianic Metaphor in Its Performative and Ethical Contexts
Authors:   Lada-Richards
Published: August 2005

An intriguing paragraph in Lucian's De Saltatione (Salt. 81) draws upon a hodge-podge of ethical, philosophical and performative traditions in its attempt to argue that the spectating experience of pantomime dancing equips the viewer with a marvellous instrument of self-exploration and self-revelation: seeing himself in the 'mirror' of the dancer, the bearer of the gaze illuminates himself. A symbol of extraordinary range and complexity, the mirror has multiple associations with the problems of perceiving, evaluating and knowing the self. But, while in the moralising narratives of 'high' culture the mirror-like reflective surface tends to be located in the soul of the sage or the lives of illustrious individuals, in Lucian's dialogue it is the pantomime, as opposed to the wise man, who delights and educates his audience by virtue of a body that becomes a magical kaleidoscope of individual self-reflections. The present article elucidates the ways in which Salt. 81 uses the symbol of the mirror in order to align pantomime dancing with the prestige of moralising discourse and examines the 'dancer as mirror' metaphor as the most important Graeco-Roman pedigree of the 'mirror of drama' analogy that dominates the complex theatrical optics of the Medieval and Renaissance European stages.
Commitment, flexibility and the choice of employment contracts
Authors: Kulkarni Subodh P. , Ramamoorthy Nagarajan
Published: August 2005

The study of the factors influencing a firm’s choice of employment contract occupies a critical role in the strategic human resource management literature. However, existing research does not adequately address an important question in an uncertain environment: Can a firm balance the apparently conflicting considerations of ‘commitment’ and ‘flexibility’, underlying employment contracts? By integrating research on transaction cost economics and the resource-based view, we propose that a firm may avoid the tradeoff between commitment and flexibility by differentiating between two types of human asset specificity: ‘firm specificity’ and ‘usage specificity’. The interplay between the two types of human asset specificity and their value-creation potential has fundamentally different implications for a firm’s choice of employment contract. By distinguishing between behavioral and competitive uncertainties, we propose that different types of uncertainties may influence levels of commitment and flexibility, and ultimately the choice of employment contract. Implications for research and practice are discussed.
Deferred Decision Making: patients’ reliance on family and physicians for cpr decisions in critical care
Authors: Kim Su Hyun , Kjervik Diane
Published: August 2005

The aim of this study was to investigate factors associated with seriously ill patients’ preferences for their family and physicians making resuscitation decisions on their behalf. Using SUPPORT II data, the study revealed that, among 362 seriously ill patients who were experiencing pain, 277 (77%) answered that they would want their family and physicians to make resuscitation decisions for them instead of their own wishes being followed if they were to lose decision-making capacity. Even after controlling for other variables, patients who preferred the option of undergoing cardiopulmonary resuscitation (CPR) in the future were twice as likely, and those who had had ventilator treatment were four-fifths less likely, to rely on their family and physicians than those who did not want CPR (odds ratio (OR)-2.28; 95% confidence interval (CI) 1.18-4.38) or those who had not received ventilator treatment (OR-0.23; 95% CI 0.06-0.90). Psychological variables (anxiety, quality of life, and depression), symptomatic variables (severity of pain and activities of daily living) and the existence of surrogates were not significantly associated with patients’ preferences for having their family and physicians make resuscitation decisions for them. Age was not a significant factor for predicting the decision-making role after controlling for other variables.
Mechanical failure analysis in a virtual reality environment
Authors: Li J-P , Thompson G
Published: August 2005

This paper is part of a research theme to develop methods that enhance risk assessment studies by the use of ‘automated’ failure analysis. The paper presents an approach to mechanical failure analysis and introduces a mechanical failure analysis module that can be used in a virtual reality (VR) environment. The module is used to analyse and predict failures in mechanical assemblies; it considers stress related failures within components, as well as failures due to component interactions. Mechanical failures are divided into two categories in this paper: material failures and interference failures. The former occur in components and the latter happen at the interface between components. Individual component failures can be analysed readily; a contribution of the mechanical failure analysis module is to predict interference failures. A mechanical failure analysis system that analyses and visualizes mechanical failures in a virtual environment has been developed. Two case studies demonstrate how the system carries out failure analysis and visualization as design parameters are changed.
Experimental investigation of fluid flow in long rectangular micro-channels
Authors: Rathnasamy R , Arakeri J H , Srinivasan K
Published: August 2005

The objective of this paper is to report new data for flow of gases, liquids, and liquid mixtures in 11 m long micro-channels. Three test sections of the following dimensions (a) 1.5 mm deep × 0.75 mm wide (MC1), (b) 0.5 mm deep × 0.95 mm wide (MC2), and (c) 0.3 mm deep × 1.0 mm wide (MC3) were cut in a serpentine form on a stainless steel substrate. The gases studied were air, nitrogen, and oxygen. The liquids used were ethanol, methanol, and their mixtures. The measured flow rate and pressure drop were used to evaluate friction factors in the micro-channels. Analysis of friction factor versus Reynolds number relation shows a perceptible dependence on channel dimensions. Transitions to turbulent regime were identified by a change in slope of friction factor versus Reynolds number curve. Transitions were mild and occurred at lower Reynolds numbers than in normal channels. The results are interpreted in terms of a channel geometry parameter.
Review of trends in solid sorption refrigeration and heat pumping technology
Authors: Critoph R E , Zhong Y
Published: August 2005

The history of adsorption cycles and the basic cycle are briefly described. The major refrigerants used are water, methanol, and ammonia. ‘Physical’ adsorbents include zeolites, active carbons, silica gels, and salts in mesoporous silica or alumina. Means of improving heat and mass transfer in both low (water, methanol) and high (ammonia) pressure systems are discussed. These include the use of conventional adsorbents that have been consolidated and more novel materials and approaches. There are a range of new thermodynamic cycles under development which have the varying goals of either using low temperature driving heat or maximizing the energy efficiency when using high temperature heat. In all machines there is a design compromise to be made between compactness (related to capital cost) and energy efficiency.
An approach of robust reliability design for mechanical components
Authors: Zhang Y M , He X D , Liu Q L , Wen B C
Published: August 2005

The reliability-based optimization, the reliability sensitivity technique, and the robust design are employed to present a practical and effective approach of robust reliability design for mechanical components on the condition of known probabilistic characteristics of original random variables. The theoretical formula of robust reliability design for mechanical components is obtained. The respective program can be used to obtain the robust reliability design parameters accurately and quickly. According to the numerical results, the method proposed is a convenient and practical robust reliability design method.
Optimization of vibration analysis inspection intervals for an offshore oil and gas water injection pumping system
Authors: Arthur N
Published: August 2005

Maintenance is often considered a ‘necessary evil’ rather than a means of delivering value to owners and operators of physical assets, and means that maintenance seldom has the requisite importance and focus required. Optimal maintenance allows the delivery of maximum productivity and profit at minimum costs, and there are two ways of determining a nominally optimal maintenance solution: qualitative and quantitative optimization. Condition-based maintenance has long been recognized as an effective strategy for maintaining critical plant, and involves the regular inspection of equipment condition to determine the need for remedial maintenance activities. The periodicity at which inspections takes place is often ill-determined and appropriate quantitative analysis seldom takes place. Such an approach often leads to excessive direct costs and can result in significant indirect costs if asset failure is considered. This paper presents a solution to this problem; the quantitative delay-time maintenance model allows the determination of the optimum condition-based maintenance inspection interval. This approach is illustrated by the application of the model to the optimization of vibration analysis intervals for an offshore oil and gas water injection pumping system and demonstrates advantages when compared with conventional qualitative approaches.
Thermodynamic modelling of a single-effect LiBr-H2O absorption refrigeration cycle
Authors: Mehrabian M A , Shahbeik A E
Published: August 2005

The objective of this paper is to develop a computer program for design and thermodynamic analysis of a single effect absorption chiller using LiBr-H2O solution as working fluid. The conditions of hot water entering and leaving the desorber, cooling water entering the absorber and leaving the condenser, chilled water entering and leaving the evaporator, as well as the approach temperatures in condenser, evaporator, desorber, and absorber, the effectiveness of solution heat exchanger, the chiller refrigeration power, and the ambient temperature are used as input data. The program then gives the thermodynamic properties of all state points, the design information of all heat exchangers in the cycle and the overall cycle performance. The results deduced from the computer program are used to study the effect of design parameters on cycle performance. For example, increasing the evaporator and generator temperatures or decreasing the condenser and desorber temperatures can improve the second-law efficiency of the cycle. It is also noticed that the temperatures of hot water, cooling water, and chilled water, respectively, at the inlet of the desorber, condenser, and evaporator have a great effect on cycle coefficient of performance. The results of this program can be used either for sizing a new refrigeration cycle or rating an existing system. It can also be used for optimization purposes. The predictions of the present program are compared with other simulating programs and qualitative agreement is achieved.
Experimental investigation of the mixing behaviour of pumpable ice slurries and ice pigs in pipe flows
Authors: Shire S , Quarini J , Ayala R S
Published: August 2005

As part of an extensive programme on the development of a novel pigging technique using crushed ice, work has been undertaken to investigate the propensity of fluids to mix in ducts when pumped. Experimental work suggests that the ice pig will tend to hold together, be self-healing, and maintain its identity under most flow conditions. The crushed ice making up the pig will tend to form a sharp interface between itself and the fluid following it. Any water resulting from melting ice will tend to be transported to the front of the pig, thus ensuring that the back of the pig will maintain its sharp interface. A simple theoretical model is proposed that is in qualitative agreement with the experimental results. Both experimental data and the proposed model are consistent with the literature. The importance of the self-healing properties of the ice pig is briefly explored.
New Organometallic Approach to Synthesize High-quality CdSe Quantum Dots
Authors: Liu Xiaobo , Lin Yuhan , Chen Yanming , An Lijia , Ji Xiangling , Jiang Bingzheng
Published: August 2005

High-quality CdSe quantum dots have been synthesized through an organometallic method with cadmium methoxide as a cadmium precursor. Without any size sorting, the FWHM (full width at half-maximum) in PL spectra almost for all CdSe samples is less than 30 nm and only 22 nm from the best sample. The emission peaks with different particle size in toluene can be tuned from 478 to 654 nm corresponding to a color change from blue-green to red.
Structure of Duplex Oxide Layer in Porous Alumina Studied by 27Al MAS and MQMAS NMR
Authors: Iijima Takahiro , Kato Seiichi , Ikeda Ryuichi , Ohki Shinobu , Kido Giyuu , Tansho Masataka , Shimizu Tadashi
Published: August 2005

A local structure analysis using 27Al multiple-quantum magic-angle-spinning (MQMAS) and MAS NMR techniques has been performed on porous alumina fabricated by the anodic oxidation of aluminum. It is suggested that the main constituents of the inner and outer oxide layers composing porous alumina are [AlO4 and AlO5] and [AlO6], respectively, and that both of the layers adopt the amorphous structure.
FTIR Studies on Selected Mesoporous Metallosilicate Molecular Sieves
Authors: Selvaraj Manickam , Kim Byong Hoo , Lee Tai Gyu
Published: August 2005

Different M–MCM-41 materials (M = Ti, V, Cr, Mn, Co, Ni, Zr, Cu, Nb, Ce, Sn, and Mo) were synthesised and characterized and the incorporation of metal ions on the silica surface also confirmed by FTIR analysis based on their ionic sizes.
Avoiding alar necrosis with post-nasal packs
Authors: Thomas L , Karagama Y G , Watson C
Published: August 2005

Foley’s catheter is used for post-nasal packing in severe epistaxis. Various methods have been described for securing the catheter in position, all of which can be associated with patient discomfort, risk of alar necrosis or unsightliness. We describe a new method to secure the Foley’s catheter without these problems. The ribbon gauze used for anterior nasal packing is tied over the catheter in multiple knots to secure it in place. This has been successfully tried on over 50 patients.
Three-dimensional reconstruction based on images from spiral high-resolution computed tomography of the temporal bone: anatomy and clinical application
Authors: Jun Beom-Cho , Song Sun-Wha , Cho Ju-Eun , Park Chan-Soon , Lee Dong-Hee , Chang Ki-Hong , Yeo Sang-Won
Published: August 2005

The aim of this study was to investigate the usefulness of a three-dimensional (3D) reconstruction of computed tomography (CT) images in determining the anatomy and topographic relationship between various important structures. Using 40 ears from 20 patients with various otological diseases, a 3D reconstruction based on the image data from spiral high-resolution CT was performed by segmentation, volume-rendering and surface-rendering algorithms on a personal computer. The 3D display of the middle and inner ear structures was demonstrated in detail. Computer-assisted measurements, many of which could not be easily measured in vivo, of the reconstructed structures provided accurate anatomic details that improved the surgeon’s understanding of spatial relationships. A 3D reconstruction of temporal bone CT might be useful for education and increasing understanding of the anatomical structures of the temporal bone. However, it will be necessary to confirm the correlation between the 3D reconstructed images and histological sections through a validation study.
An approach to tracheostomy in a patient with an expandable metallic tracheal stent
Authors: Madden Brendan P , Sheth Abhijat
Published: August 2005

With increasing use of expandable metallic stents to manage patients with a variety of endobronchial pathologies, some will have a subsequent need for tracheostomy insertion. We describe a successful technique to insert a tracheostomy using rigid and fibre-optic bronchoscopy in a patient who had an 8 cm expandable metallic tracheal stent deployed previously on account of tracheomalacia.
Influence of carbon dioxide laser irradiation on the morphology and function of guinea pig cochlea
Authors: Ren DongDong , Sun JingWU , Wan GuangLun , Yang Feng , Shen Fang
Published: August 2005

Both experimental and clinical studies have demonstrated that carbon dioxide laser is suitable for stapedotomy. The aim of this study was to investigate morphological, electrophysiological and functional changes in the inner ear after irradiation with CO2 laser set with different energy parameters.

A cochleostomy in the basal cochlear turn of guinea pig cochleae was performed with CO2 laser of 1, 2 and 3 w, respectively. The cochleae were removed three weeks after laser irradiation. The auditory evoked brainstem response (ABR) was measured before and
after laser application and immediately before removal of the cochlea. Immunohistochemical methods were used to examine inducible nitric oxide synthase (iNOS/NOSII) and heat-shock protein 70(Hsp70) concentrations in the cochlea after laser application. The organ of Corti was studied by scanning electron microscopy.

Worse hearing loss was observed in animals receiving higher-power CO2 laser. These findings correlated with more intense injury of the cochlear ultrastructure and with positiveexpression of iNOS and Hsp70 in spiral ganglion cells, nerve fibres, supporting
cells of the organ of Corti and cells of the spiral ligament.

The CO2 laser as a noncontact procedure is shown to be effective and safe if the total amount of energy is kept within the limits applied in this study. Nitric oxide and stressproteins play important roles in the traumatic mechanism of the inner ear, which are related tohearing loss and injury of the ultrastructure of the inner ear.
Mesotympanic sarcoidosis
Authors: Banerjee A S , Gleeson M J
Published: August 2005

Sarcoidosis often presents with signs and symptoms within the head and neck. In this region, it most commonly affects the nose, larynx, parotid and cervical lymph nodes. Within the ear, it usually causes sensorineural hearing loss of varying severity. We report a patient in whom sarcoidosis involved the middle ear and presented with a conductive hearing loss. Granulomata were found in the middle ear during an exploratory tympanotomy. The granulomatous process had caused necrosis of the long process of incus and was also encasing the chorda tympani nerve. Histological examination confirmed the diagnosis.
Internal jugular vein thrombosis due to ovarian hyper-stimulation syndrome
Authors: El-Ghazali A M S , Hill D
Published: August 2005

Internal jugular vein thrombosis from non-otological causes is not well documented in the otolaryngology literature. The authors report a case of left internal jugular vein thrombosis due to severe ovarian hyperstimulation syndrome. Causes, investigations and treatment of internal jugular vein thrombosis from non-otological causes are discussed.
Cerebrospinal fluid otorhinorrhoea due to inner-ear malformations: clinical presentation and new perspectives in management
Authors: Tyagi Isha , Syal Rajan , Goyal Amit
Published: August 2005

Objective: In children cerebrospinal fluid (CSF) otorhinorrhoea can be due to congenital inner-ear malformations. Cochlear dysplasia associated with a defect in the stapes footplate is usually the cause of the CSF leak. Repair of the CSF leak in these cases is usually done by packing the vestibule with muscle or fascia. This traditional method of repair has a 30 to 60 per cent failure rate.

Material and methods: CSF otorhinorrhoea due to congenital inner-ear anomalies in four patients was repaired using multiple-layer packing of the vestibule with glue, muscle and fascia, reinforced by a pedicle temporalis muscle graft. Intra-operatively, continous lumbar drainage wasperformed.

Results: Repair of the CSF leak was successful in four cases and no recurrence was noticed. Inner-ear magnetic resonance imaging (MRI) using three-dimensional fast-spin echo (3D
FSE) T2-weighted imaging (T2WI) and 3D steady-state free precession (FIESTA) sequences was found to be a very helpful, noninvasive investigation to localize the site and route of the CSF leak.

Conclusions: Children presenting with recurrent meningitis and CSF rhinorrhoea should be investigated for congenital inner-ear anomalies. In these cases CSF fistulae should be repaired using fibrin or cyanoacrylate glue and intra-operative continuous lumbar drainage; 3D FSE T2WI and 3D FIESTA MRI sequences of the inner ear are helpful.
Endoscopic repair of frontal sinus cerebrospinal fluid leaks
Authors: Woodworth B A , Schlosser R J , Palmer J N
Published: August 2005

Objective: To describe endoscopic management of frontal sinus cerebrospinal fluid (CSF) leaks.

Study design: Retrospective.

Methods: We reviewed all frontal sinus CSF leaks treated using an endoscopic approach at ourinstitutions from 1998 to 2003. CSF leaks originated immediately adjacent to or within the frontal recess or frontal sinus proper for inclusion in the study. Data collected included demographics, presenting signs and symptoms, site and size of skull-base defect, surgical approach, repair technique, and clinical follow up.

Results: Seven frontal sinus CSF leaks in six patients were repaired endoscopically. Average age of presentation was 45 years (range 25–65 years). Aetiology was idiopathic (three), congenital (one), accidental trauma (one), and surgical trauma (two). All patients presented with CSF rhinorrhea; two patients presented with meningitis. Four defects originated in the frontal recess, while two others involved the posterior table and frontal sinus outflow tract. Four patients had associated encephaloceles. We performed endoscopic repair in all six patients withone patient requiring an adjuvant osteoplastic flap without obliteration. All repairs were successful at the first attempt with a mean follow up of 13 months. All frontal sinuses remained patent on both post-operative endoscopic and radiographic exam.

Conclusions: Endoscopic repair of frontal sinus CSF leaks and encephaloceles can be an effective method if meticulous attention is directed toward preservation of the frontal sinus outflow tract, thus avoiding an osteoplastic flap and obliteration. The major limiting factor for an endoscopic approach is extreme extension superiorly or laterally within the posterior table beyond the reach of current instrumentation.
Comparison of effects of dry versus wet swallowing on Eustachian tube function via a nine-step inflation/deflation test
Authors: Adali M Kemal , Uzun Cem
Published: August 2005

The aim of the present study is to evaluate the effect of swallowing type (dry versus wet) on the outcome of a nine-step inflation/deflation tympanometric Eustachian tubefunction (ETF) test in healthy adults.

Fourteen normal healthy volunteers, between 19 and 28 years of age, were included in the study. The nine-step test was performed in two different test procedures: (1) test with dry swallows (dry test procedure) and (2) test with liquid swallows (wet test procedure). If the equilibration of middle-ear (ME) pressure was successful in all the steps of the nine-step test, ETF was considered ‘Good’. Otherwise, the test was considered ‘Poor’, and the test was repeated at a second session.

In the dry test procedure, ETF was ‘Good’ in 21 ears at the first session and in 24 ears after the second session (p > 0.05). However, in the wet test procedure, ETF was ‘Good’ in 13 ears at the first session and in 21 ears after the second session (p < 0.05).

At the first session, ETF was ’Good’ in 21 and 13 ears in the dry and wet test procedures, respectively. The difference was statistically significant (p < 0.05). However, after the second session, the overall number of ears with ‘Good’ tubal function was almost the same in both test procedures (24 ears at dry test procedures versus 21 ears at wet test procedures;p > 0.05).

Dry swallowing seems to be more effective for the equilibration of ME pressure.
Thus, a single-session dependent evaluation of ETF may be efficient for the dry test procedure of the nine-step test. Swallowing with water may be easier for subjects, but a repetition of the test at a second session may be necessary when the test result is ‘Poor’.
Early post-operative morbidity after tympanostomy tube insertion
Authors: Allen Jacqui , Morton Randall P , Ahmad Zahoor
Published: August 2005

Insertion of ventilation tubes is regarded as a simple, effective and safe treatment for recurrent otitis media or prolonged middle-ear effusions. We conducted a prospective observational study of 112 children to ascertain what early post-operative complications were experienced. Our findings were consistent with previously published figures for post-surgical otorrhoea and obstruction rates, at 13.5 per cent and 4 per cent (by ear), respectively, using intra-operative administration of antibiotic/steroid ear drops. We identified unique characteristics of differing ethnic groups with regard to findings at surgery and post-operative outcomes. There was a tendency for grommets placed in the left ear to be extruded early and Maori andPacific Islanders were significantly more likely to have a non-functioning tube (blocked or extruded) in the early post-operative period. Overall, one in four children developed a post-operative complication (otorrhoea or non-functioning tube) suggesting that early and close follow up may allow timely identification and intervention where required.
Hearing screening of infants in Neonatal Unit, Hospital Universiti Sains Malaysia using transient evoked otoacoustic emissions
Authors: Mohd Khairi M D , Din S , Shahid H , Normastura A R
Published: August 2005

The objective of this prospective study was to report on the prevalence of hearing impairment in the neonatal unit population. From 15 February 2000 to 15 March 2000 and from 15 February 2001 to 15 May 2001, 401 neonates were screened using transient evoked otoacoustic emissions (TEOAE) followed by second-stage screening of those infants who failed the initial test. Eight (2 per cent) infants failed one ear and 23 (5.74 per cent) infants failed both ears, adding up to 7.74 per cent planned for second-stage screening. Five out of 22 infants who came for the follow up failed the screening, resulting in a prevalence of hearing impairment of 1 per cent (95 per cent confidence interval [95% CI]: 0.0–2.0). Craniofacial malformations, very low birth weight, ototoxic medication, stigmata/syndromes associated with hearing loss and hyperbilirubinaemia at the level of exchange tranfusion were identified to be independent significant risk factors for hearing impairment, while poor Apgar scores and mechanical ventilation of more than five days were not. In conclusion, hearing screening in high-risk neonates revealed a total of 1 per cent with hearing loss. The changes in the risk profile indicate improved perinatal handling in a neonatal population at risk for hearing disorders.
Epistaxis: Are temperature and seasonal variations true factors in incidence?
Authors: Bray D , Giddings C E B , Monnery P , Eze N , Lo S , Toma AG
Published: August 2005

Objective: To investigate the previously documented inverse association between ambient temperature and presentation rates for patients with epistaxis and seasonal variation of emergency presentation rates for patients with epistaxis.

Study design: A retrospective analysis of all consecutive emergency patients with epistaxis presenting to hospital from the community over a five-year period, 1997–2002 (1830 days), including those who required admission to hospital with epistaxis over the same period. Patients in whom there was a clear aetiology for the epistaxis (traumatic, recurrent, iatrogenic, coagulopathic and hypertensive) were excluded.

Setting: A tertiary referral centre in south-west London serving a population in excess of 2.8 million.

Method: A retrospective analysis of all patients presenting or admitted to St George’s Hospital with epistaxis over a five-year period. Daily ambient temperature readings from London Heathrow airport were recorded for the same period. Presentations were correlated with monthly temperature variations and the month itself. Statistical analysis with Pearson’s correlation coefficient was performed.

Results: 1373 patients with epistaxis presented to our department, of whom 386 (28.1 per cent) were admitted to hospital. No correlation is seen between ambient temperature and presentation rate for patients with epistaxis. No seasonal preponderance is noted for presentation rate (Pearson r = 0.160, p = 0.221) in this series.

Conclusion: To our knowledge, this is the largest study to date examining ambient temperature association and epistaxis, and the first to investigate presentation rate in place of admission rate. We feel that the exclusion of all patients with epistaxis not admitted to hospital introduces a bias. In this series, there is no correlation between ambient temperature, seasonal preponderance, presentation rate or admission rate for patients with epistaxis. This is contrary to previously reported findings. We do not support the view that there is a relationship between epistaxis and temperature or seasonal variation. This contradicts the current belief that incidence of epistaxis displays seasonality, and has implications for the allocation of resources for healthcare provision within ENT departments.
An MSc Course Module: Wind Turbine Measurement Techniques
Authors: Hansen Kurt S. , Pedersen Knud Ole Helgesen
Published: August 2005

The 2-year MSc in Wind power engineering at the Technical University of Denmark comprises modules from core engineering teaching and from other modules specifically designed to the MSc. This Note outlines the content of such a specific module on the subject of wind turbine measurement. The lectures, practical exercises and work related to measurements from an operating 500 kW turbine are described.
Trajectories for Detached Wind Turbine Blades
Authors: Madsen K.H. , Frederiksen S.O. , Gjellerup C. , Skjoldan P.F.
Published: August 2005

Computer simulated and measured trajectories of a scaled blade, as detached from a wind turbine, have been compared for a model-blade (0.6 m long), released from a custom-made blade-throwing machine. The simulations are based on a wing strip theory, using static airfoil data in combination with a dynamic stall model. The measured movement of the detached model-blade was found to be in good agreement with the simulations, although throwing distances in most cases tend to be longer in the simulations than in the experiments. The dynamic stall model mainly affects the ‘throwing width’ parallel to the wind direction and has only a negligible affect on the absolute throwing distance.