bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging of Serotonin Mechanisms in Epilepsy
Authors: Chugani Harry T. , Chugani Diane C.
Published: November 2005

Advances in positron emission tomography (PET) techniques have allowed the measurement and imaging of neurotransmitter synthesis, transport, and receptor binding to be performed in vivo. With regard to epileptic disorders, imaging of neurotransmitter systems not only assists in the identification of epileptic foci for surgical treatment, but also provides insights into the basic mechanisms of human epilepsy. Recent investigative interest in epilepsy has focused on PET imaging of tryptophan metabolism, via the serotonin and kynurenine pathways, as well as on imaging of serotonin receptors. This review summarizes advances in PET imaging and how these techniques can be applied clinically for epilepsy treatment.
The Terminal Man—from Science Fiction to Therapy
Authors: Schwartz Theodore H.
Published: November 2005

Automated Seizure Abatement in Humans Using Electrical Stimulation

Osorio I, Frei MG, Sunderam S, Giftakis J, Bhavaraju NC, Schaffner SF, Wilkinson SB

Ann Neurol 2005;57:258–268

The need for novel, efficacious, antiseizure therapies is widely acknowledged. This study investigates in humans the feasibility, safety, and efficacy of high-frequency electrical stimulation (HFES; 100–500 Hz) triggered by automated seizure detections. Eight patients were enrolled in this study, which consisted of a control and an experimental phase. HFES was delivered directly to the epileptogenic zone (local closed-loop) in four patients and indirectly, through anterior thalami (remote closed-loop), to the other four patients for every other automated seizure detection made by a validated algorithm. Interphase (control vs. experimental phase) and intraphase (stimulated vs. nonstimulated) comparisons of clinical seizure rate and relative severity (clinical and electrographic) were performed, and differences were assessed by using effect size. Patients were deemed “responders” if seizure rate was reduced by at least 50%; the remaining patients were deemed “nonresponders.” All patients completed the study; rescue medications were not required; 1,491 HFESs (0.2% triggered afterdischarges) were included. Mean change in seizure rate in the local closed-loop group was −55.5% (–100 to +36.8%); three of four responders had a mean change of −86% (–100 to −58.8%). In the remote closed-loop, the mean change of seizure rate was −40.8% (–72.9 to +1.4%); two of four responders had a mean change of −74.3% (–75.6 to −72.9%). Mean effect size was zero in the local closed-loop (responders: beneficial and medium to large in magnitude) and negligible in the remote closed-loop group (responders: beneficial and medium to large). HFES effects on epileptogenic tissue were immediate and also outlasted the stimulation period. This study demonstrates the feasibility and short-term safety of automated HFES for seizure blockage and also raises the possibility that it may be beneficial in pharmacoresistant epilepsies.
Sudden Death and Epilepsy
Authors: Ben-Menachem Elinor
Published: November 2005

Case–control Study of SUDEP

Langan Y, Nashef L, Sander JW

Neurology 2005;64:1131–1133

Purpose

To examine the influence of various factors on the risk of sudden unexpected death in epilepsy (SUDEP).

Methods

The authors investigated 154 cases in which a postmortem examination was performed. Each case had four controls with epilepsy from the community, matched for age and geographic location. Backward stepwise conditional logistic regression analysis was performed, and odds ratios for risk and protection were determined.

Results

The risk of SUDEP was increased with a history of generalized tonic–clonic seizures in the previous 3 months (odds ratio [OR]: 13.8; 95% CI: 6.6 to 29.1). The presence of supervision at night was found to be protective (OR: 0.4; 95% CI: 0.2 to 0.8) when a supervising individual shared the same bedroom or when special precautions such as a listening device were used (OR: 0.1; 95% CI: 0.0 to 0.3).

Conclusions

This work lends support to the view that SUDEP is a seizure-related phenomenon and that control of tonic–clonic seizures is important in its prevention. Nocturnal supervision seems to protect against SUDEP.
Update on the Neurobiology of Alcohol Withdrawal Seizures
Authors: Rogawski Michael A.
Published: November 2005

Abrupt cessation of alcohol intake after prolonged heavy drinking may trigger alcohol withdrawal seizures. Generalized tonic–clonic seizures are the most characteristic and severe type of seizure that occur in this setting. Generalized seizures also occur in rodent models of alcohol withdrawal. In these models, the withdrawal seizures are triggered by neuronal networks in the brainstem, including the inferior colliculus; similar brainstem mechanisms may contribute to alcohol withdrawal seizures in humans. Alcohol causes intoxication through effects on diverse ion channels and neurotransmitter receptors, including GABAA receptors—particularly those containing δ subunits that are localized extrasynaptically and mediate tonic inhibition—and N-methyl-D-aspartate (NMDA) receptors. Alcohol dependence results from compensatory changes during prolonged alcohol exposure, including internalization of GABAA receptors, which allows adaptation to these effects. Withdrawal seizures are believed to reflect unmasking of these changes and may also involve specific withdrawal-induced cellular events, such as rapid increases in α4 subunit–containing GABAA receptors that confer reduced inhibitory function. Optimizing approaches to the prevention of alcohol withdrawal seizures requires an understanding of the distinct neurobiologic mechanisms that underlie these seizures.
Chronic Cortical Injury and Epileptogensis: A Possible Role for Intracellular Chloride Homeostasis
Authors: Dudek F. Edward , Staley Kevin J.
Published: November 2005

Impaired Cl– Extrusion in Layer V Pyramidal Neurons of Chronically Injured Epileptogenic Neocortex

Jin X, Huguenard JR, Prince DA

J Neurophysiol 2005;93:2117–2126

In the mature brain, the K+/Cl– cotransporter KCC2 is important in maintaining low [Cl–]i, resulting in hyperpolarizing GABA responses. Decreases in KCC2 after neuronal injuries result in increases in [Cl–]i and enhanced neuronal excitability due to depolarizing GABA responses. We used the gramicidin perforated-patch technique to measure ECl(∼ EGABA) in layer V pyramidal neurons in slices of partially isolated sensorimotor cortex of adult rats to explore the potential functional consequence of KCC2 downregulation in chronically injured cortex. EGABA was measured by recording currents evoked with brief GABA puffs at various membrane potentials. No significant difference was found in ECl between neurons in control and undercut animals (–71.2 ± 2.6 and −71.8 ± 2.8 mV, respectively). However, when loaded with Cl– by applying muscimol puffs at 0.2 Hz for 60 seconds, neurons in the undercut cortex had a significantly shorter time constant for the positive shift in ECl during the Cl– loading phase (4.3 ± 0.5 s for control and 2.2 ± 0.4 s for undercut; p < 0.01). The positive shift in ECl 3 seconds after the beginning of Cl– loading was also significantly larger in the undercut group than in the control, indicating that neurons in undercut cortex were less effective in maintaining low [Cl–]i during repetitive activation of GABAA receptors. Application of furosemide eliminated the difference between the control and undercut groups for both of these measures of [Cl–]i regulation. The results suggest an impairment in Cl– extrusion resulting from decreased KCC2 expression that may reduce the strength of GABAergic inhibition and contribute to epileptogenesis.
Targeting the Brain: Focal Delivery of Natural Anticonvulsant Molecules
Authors: Mazarati Andrey
Published: November 2005

Seizure Suppression and Lack of Adenosine A1 Receptor Desensitization after Focal Long-term Delivery of Adenosine by Encapsulated Myoblasts

Güttinger M, Padrun V, Pralong WF, Boison D

Exp Neurol 2005;193:53–64

Adenosine is an important inhibitory modulator of brain activity. In a previous ex vivo gene-therapy approach, local release of adenosine by encapsulated fibroblasts implanted into the vicinity of an epileptic focus was sufficient to provide transient protection from seizures (Huber A, Padrun V, Deglon N, Aebischer P, Mohler H, Boison D. Grafts of adenosine-releasing cells suppress seizures in kindling epilepsy. Proc Natl Acad Sci USA 2001; 98:7611–7616). Long-term seizure suppression beyond 2 weeks was precluded by limited life expectancy of the encapsulated fibroblasts. To study the feasibility for long-term seizure suppression by adenosine-releasing brain implants, in the present contribution, mouse C2C12 myoblasts were engineered to release adenosine by genetic inactivation of adenosine kinase. After encapsulation, the myoblasts were grafted into the lateral brain ventricles of epileptic rats kindled in the hippocampus. Although seizure activity in animals with wild-type implants remained unaltered, 1 week after grafting, all rats with adenosine-releasing implants ( n = 25) displayed complete protection from convulsive seizures and a corresponding reduction of afterdischarges in EEG recordings. The duration of seizure suppression was maintained for a period of 3 weeks in 50% of the animals, ranging to a maximum of 8 weeks in one animal. During the course of these experiments, adenosine A1 receptors remained responsive to selective agonists and antagonists, indicating a lack of desensitization of A1 receptors after local long-term exposure to adenosine. Furthermore, local release of adenosine did not affect locomotor activity, whereas systemic application of the A1 agonist 2-chloro- N6-cyclopentyladenosine caused strong sedation. Thus, the local release of adenosine by cellular implants provides a feasible option for a potential side effect–free approach for the long-term treatment of focal epilepsies.
The Links between Diabetes and Cardiovascular Disease
Authors: SCHNELL OLIVER
Published: November 2005

The aim of this study was to review current studies relevant to the link between impaired glucose tolerance (IGT), diabetes, and cardiovascular disease.Cardiovascular disease is a major cause of the reduction in life expectancy in patients with diabetes. Seventy‐five percent of diabetic patients die prematurely of cardiovascular complications. Both prediabetes and diabetes highly predipose to cardiovascular alterations. IGT and even the upper‐normal of nondiabetic glucose values are associated with an increased cardiovascular risk. The risk of heart disease is increased up to 15 years prior diagnosis of diabetes. Patients with chronic or acute cardiovascular disease and no previous diagnosis of diabetes frequently present with either IGT or diabetes. Patients with cardiovascular disease and no previous diagnosis of diabetes need to be screened for diabetes with an oral glucose tolerance test. In acute coronary syndromes, lowering glucose levels to the near‐normal range with insulin is highly beneficial. Early and rigorous improvement of metabolic control is highly supportive in improving the cardiovascular outcome in patients with dysglycemia. Preventive treatment strategies, which include multiple approaches, are required to overcome the burden of cardiovascular disease in diabetes and IGT.
Drug‐Eluting Stents for Interventional Revascularization of Coronary Multivessel Disease
Authors: ONG ANDREW T.L. , VAN DER GIESSEN WILLEM J.
Published: November 2005

The treatment of coronary artery disease has changed over the past 35 years since the introduction of coronary artery bypass surgery in 1968. Percutaneous coronary intervention, introduced in 1977 with balloon angioplasty, was accelerated by the establishment of elective stent placement in 1994, together with the development of suitable antiplatelet regimes. In 2002, DES were made commercially available, following the results of clinical trials in single lesions. A meta‐analysis of four randomized clinical trials comparing bare stents to bypass surgery for multivessel disease conducted in the 1990s demonstrate no mortality difference at 1 year. Similar 5‐year outcomes have been reported by the ARTS trial. These trials, however, showed that repeat revascularization was much higher in the stent arm, due to restenosis. Various single center (RESEARCH, T‐SEARCH) and multicenter (ARTS II) registries have consistently showed a low need for repeat intervention in patients with multivessel disease with the use of DES. Three major trials comparing DES against bypass surgery are ongoing or about to start and will determine the optimum revascularization therapy in multivessel disease. The recently commenced SYNTAX randomized trial will enroll only three‐vessel or left main disease, while the upcoming FREEDOM and ongoing CARDia trial will specifically enroll diabetic patients only with multivessel disease. Results for these trials are expected in 2006‐2007 at the earliest.
Intracoronary Thermography: Does It Help Us in Clinical Decision Making?
Authors: TOUTOUZAS KONSTANTINOS , DRAKOPOULOU MARIA , STEFANADI ELLI , SIASOS GERASIMOS , STEFANADIS CHRISTODOULOS
Published: November 2005

The concept of the “vulnerable” plaque has recently emerged to explain how quiescent atherosclerotic lesions evolve to cause clinical events. The morphologic and immunologic determinants specific for the vulnerable plaque have been reported: a large lipid core (≥40% plaque volume) composed of free cholesterol crystals, cholesterol esters, and oxidized lipids impregnated with tissue factor; a thin fibrous cap depleted of smooth muscle cells and collagen; an outward (positive) remodeling; inflammatory cell infiltration of fibrous cap and adventitia (mostly monocyte‐macrophages, some activated T cells, and mast cells); and increased neovascularity. Despite the large amount of information regarding the morphological characteristics of remote lesions, we lack studies with functional assessment of nonculprit lesions. Coronary thermography is a technique for functional assessment of coronary atherosclerotic plaques. Several catheter designs have been proposed. There are catheters with thermistor(s) and wires with thermal sensors at the distal tip. All designs have several advantages and disadvantages. Despite the current limitations of coronary thermography, we gained important pathophysiological and clinical information regarding the vulnerability of atheromatic plaques. It has been documented both experimentally and clinically that increased heat generation is associated with increased macrophage concentration within the plaque. The correlation between local inflammatory involvement and local heat generation has also been observed with the peripheral inflammatory markers such as C‐reactive protein. Whether systemic treatment, with agents such as statins or interventional techniques, such as drug‐eluting stents, will have an impact on stabilizing vulnerable plaques need to be determined in future studies. In conclusion, although there are several techniques for evaluating morphologically atheromatic plaques, thermography is a promising method for the functional assessment of vulnerable plaque and has been introduced into clinical practice, with a good predictive value for clinical events in patients with increased temperature in the atherosclerotic plaque.
Atrial and Ventricular Septal Defects Can Safely Be Closed by Percutaneous Intervention
Authors: HEIN RALPH , BÜSCHECK FRANZISKA , FISCHER EVELYN , LEETZ MICHAELA , BAYARD MARGARETH TAAFFE YVES , OSTERMAYER STEFAN , RESCHKE MADLEN , LANG KLAUS , RÖMER ALBRECHT , WILSON NEIL , SIEVERT HORST
Published: November 2005

Various transcatheter devices and methods to close congenital heart defects are currently available. Devices have been designed specifically for atrial septal defect (ASD), patent foramen ovale (PFO), and ventricular septal defect (VSD) closure. The trend in interventional treatment of intracardiac shunts shows toward defect‐specific systems. The PFO is a tunnel defect requiring occluders that adapt to its length while common ASD strongly vary in their diameter, making a large scale of device sizes indispensable. VSDs are predominantly sealed by coils or tissue‐adapted devices like muscular or perimembranous occluders. Since VSDs may occur with an aneurysm (VSA), a multiperforated septum, an instable myocardial situation (postinfarction) or a high interventricular pressure gradient, closure of these defects is regarded sometimes as complicated. But during the last 30 years (since King and Mills implanted the first double‐umbrella occluding system) several studies have proven procedure efficacy and safety of both ASD and VSD closure. This article reviews a large scale of studies and includes our single center data on 1,609 PFO, ASD, and VSD patients.
Urinary 6‐sulfatoxymelatonin levels and their correlations with lifestyle factors and steroid hormone levels
Authors: Schernhammer Eva S. , Kroenke Candyce H. , Dowsett Mitch , Folkerd Elizabeth , Hankinson Susan E.
Published: November 2005

Abstract:  Exposure to light at night, as experienced by rotating night shift workers, has been related to lower circulating levels of melatonin, a hormone with recognized cancer protective properties. However, little is known about the relationship of other lifestyle factors or endogenous sex steroid hormones with melatonin levels. We examined cross‐sectional associations of age, reproductive and menopausal factors, body mass index (BMI), alcohol consumption, smoking history, night shift work, as well as several other breast cancer risk factors, and circulating sex steroid hormone levels with creatinine‐adjusted morning urinary melatonin (6‐sulfatoxymelatonin, aMT6s) levels. Participants were 459 healthy, primarily premenopausal (age range 33–50 yr) women from the Nurses’ Health Study II (NHS II). Using multiple linear regression, we computed least‐square mean hormone levels across categories of lifestyle factors. Age was inversely related to aMT6s levels, particularly before menopause (premenopausal women, ≤39 yr versus ≥49 yr; aMT6s, 20.8 ng/mg versus 11.8 ng/mg creatinine; P for trend, 0.02). In multivariate analyses, BMI was significantly and inversely associated with aMT6s levels (P for trend, <0.01). Higher pack‐years of smoking were associated with significantly lower aMT6s levels (never smoker versus 15+ pack‐years, aMT6s = 17.4 ng/mg versus 12.3 ng/mg creatinine; P for trend, 0.04). We also observed a positive association between parity and aMT6s levels (P for trend, <0.01), but no other reproductive factors nor any of the sex hormones (estradiol, progesterone, estrone, estrone sulfate, dehydroepiandrostenedione, dehydroepiandrostenedione sulfate, testosterone, and androstenedione), as measured either in the luteal or the follicular phase of the menstrual cycle, were significantly associated with aMT6s. In conclusion, higher age, BMI, and heavy smoking were significantly related to lower levels of melatonin, whereas parity was significantly associated with higher aMT6s levels. Melatonin levels may be one mechanism through which these factors influence the development of cancer, but more studies are needed to elucidate these mechanisms definitively.
Mutual effects of proton and sodium chloride on oxygenation of liganded human hemoglobin
Authors: Lepeshkevich Sergei V. , Dzhagarov Boris M.
Published: November 2005

The different effects of pH and NaCl on individual O2‐binding properties of α and β subunits within liganded tetramer and dimer of human hemoglobin (HbA) were examined in a number of laser time‐resolved spectroscopic measurements. A previously proposed approach [Dzhagarov BM & Lepeshkevich SV (2004) Chem Phys Lett390, 59–64] was used to determine the extent of subunit dissociation rate constant difference and subunit affinity difference from a single flash photolysis experiment. To investigate the effect of NaCl concentration on the association and dissociation rate constants we carried out a series of experiments at four different concentrations (0.1, 0.5, 1.0 and 2.0 m NaCl) over the pH range of the alkaline Bohr effect. As the data suggest, the individual properties of the α and β subunits within the completely liganded tetrameric hemoglobin did not depend on pH under salt‐free conditions. However, different effects NaCl on the individual kinetic properties of the α and β subunits were revealed. Regulation of the O2‐binding properties of the α and β subunits within the liganded tetramer is proposed to be attained in two quite different ways.
Secondary structure assignment of mouse SOCS3 by NMR defines the domain boundaries and identifies an unstructured insertion in the SH2 domain
Authors: Babon Jeffrey J. , Yao Shenggen , DeSouza David P. , Harrison Christopher F. , Fabri Louis J. , Liepinsh Edvards , Scrofani Sergio D. , Baca Manuel , Norton Raymond S.
Published: November 2005

SOCS3 is a negative regulator of cytokine signalling that inhibits Janus kinase‐signal transduction and activator of transcription (JAK‐STAT) mediated signal tranduction by binding to phosphorylated tyrosine residues on intracellular subunits of various cytokine receptors, as well as possibly the JAK proteins. SOCS3 consists of a short N‐terminal sequence followed by a kinase inhibitory region, an extended SH2 domain and a C‐terminal suppressor of cytokine signalling (SOCS) box. SOCS3 and the related protein, cytokine‐inducible SH2‐containing protein, are unique among the SOCS family of proteins in containing a region of mostly low complexity sequence, between the SH2 domain and the C‐terminal SOCS box. Using NMR, we assigned and determined the secondary structure of a murine SOCS3 construct. The SH2 domain, unusually, consists of 140 residues, including an unstructured insertion of 35 residues. This insertion fits the criteria for a PEST sequence and is not required for phosphotyrosine binding, as shown by isothermal titration calorimetry. Instead, we propose that the PEST sequence has a functional role unrelated to phosphotyrosine binding, possibly mediating efficient proteolytic degradation of the protein. The latter half of the kinase inhibitory region and the entire extended SH2 subdomain form a single α‐helix. The mapping of the true SH2 domain, and the location of its C terminus more than 50 residues further downstream than predicted by sequence homology, explains a number of previously unexpected results that have shown the importance of residues close to the SOCS box for phosphotyrosine binding.
Scale Effects of Hydrostratigraphy and Recharge Zonation on Base Flow
Authors: Juckem Paul F. , Hunt Randall J. , Anderson Mary P.
Published: November 2005

Uncertainty regarding spatial variations of model parameters often results in the simplifying assumption that parameters are spatially uniform. However, spatial variability may be important in resource assessment and model calibration. In this paper, a methodology is presented for estimating a critical basin size, above which base flows appear to be relatively less sensitive to the spatial distribution of recharge and hydraulic conductivity, and below which base flows are relatively more sensitive to this spatial variability. Application of the method is illustrated for a watershed that exhibits distinct infiltration patterns and hydrostratigraphic layering. A ground water flow model (MODFLOW) and a parameter estimation code (UCODE) were used to evaluate the influence of recharge zonation and hydrostratigraphic layering on base flow distribution. Optimization after removing spatial recharge variability from the calibrated model altered base flow simulations up to 53% in watersheds smaller than 40 km2. Merging six hydrostratigraphic units into one unit with average properties increased base flow residuals up to 83% in basins smaller than 50 km2. Base flow residuals changed <5% in watersheds larger than 40 and 50 km2 when recharge and hydrostratigraphy were simplified, respectively; thus, the critical basin size for the example area is ∼40 to 50 km2. Once identified for an area, a critical basin size could be used to guide the scale of future investigations. By ensuring that parameter discretization needed to capture base flow distribution is commensurate with the scope of the investigation, uncertainty caused by overextending uniform parameterization or by estimating extra parameter values is reduced.
The significance of geographic range size for spatial diversity patterns in Neotropical palms
Authors: Kreft Holger , Sommer Jan H , Barthlott Wilhelm
Published: November 2005

We examined the effect of range size in commonly applied macroecological analyses using continental distribution data for all 550 Neotropical palm species (Arecaceae) at varying grain sizes from 0.5° to 5°. First, we evaluated the relative contribution of range‐restricted and widespread species on the patterns of species richness and endemism. Second, we analysed the impact of range size on the predictive value of commonly used predictor variables. Species sequences were produced arranging species according to their range size in ascending, descending, and random order. Correlations between the cumulative species richness patterns of these sequences and environmental predictors were performed in order to analyse the effect of range size. Despite the high proportion of rare species, patterns of species richness were found to be dominated by a minority of widespread species (∼20%) which contained 80% of the spatial information. Climatic factors related to energy and water availability and productivity accounted for much of the spatial variation of species richness of widespread species. In contrast, species richness of range‐restricted species was to a larger extent determined by topographical complexity. However, this effect was much more difficult to detect due to a dominant influence of widespread species. Although the strength of different environmental predictors changed with spatial scale, the general patterns and trends proved to be relatively stabile at the examined grain sizes. Our results highlight the difficulties to approximate causal explanations for the occurrence of a majority of species and to distinguish between contemporary climatic factors and history.
Assemblages of wood‐inhabiting fungi along the gradients of succession and naturalness in boreal pine‐dominated forests in Fennoscandia
Authors: Junninen Kaisa , Similä Maarit , Kouki Jari , Kotiranta Heikki
Published: November 2005

In boreal forests, the level of naturalness and the stage of succession explain most of the variation in forest structure within a particular forest type. Thus, these two factors should also have a major effect on species assemblages in forests, at least on species groups associated with wood. The present study is the first attempt to analyze empirically the simultaneous effects of forest succession and naturalness on wood‐inhabiting fungi, a taxonomic group of special ecological importance. The study area was situated in eastern Finland, middle boreal zone. A total of 41 study plots were established in Pinus sylvestris forests representing three levels of forest naturalness: natural, seminatural and intensively managed forests. Five stages of succession were distinguished according to the age of the dominating tree layer (<10, 40, 70, 110, and >150 yr old), except in managed forests where only four stages were available. A total of 5328 records of 195 species of fungi were made. The first, open stage of succession was clearly the most species‐rich period of succession in all levels of forest naturalness. In natural and seminatural forests, the first stage of succession was also very distinctive in its fungal composition, and thus of special value in protecting biodiversity in boreal forests. In the succession following the first stage, the level of naturalness had more effect on assemblages of fungi than did the stage of succession. Intensive forest management affects threatened species particularly. In conclusion, natural young stages of succession should also be included in the network of boreal forest reserves.
Simulation of Transient Heat Transfer of Sandwich Pipes With Active Electrical Heating
Authors: Su Jian , Cerqueira Djane R. , Estefen Segen F.
Published: November 2005

This paper presents an analysis of transient heat transfer in sandwich pipelines with active electrical heating. The mathematical models governing the heat conduction in the composite pipeline and the energy transport in the produced fluid were solved by using finite difference methods. Numerical results of computational simulation of cool-down for three sandwich pipeline configurations under typical production conditions were presented. The analysis showed that the sandwich pipe with active heating is a viable solution to meet severe flow assurance requirements of ultra-deepwater oil production even under unplanned and prolonged cool-down conditions.
Numerical Investigation of Two-Dimensional Sloshing: Nonlinear Internal Waves
Authors: Valentine Daniel T.
Published: November 2005

In this paper we examine internal sloshing motions in 2-D numerical wave tanks subjected to horizontal excitation. In all of the cases studied, the rectangular tank of liquid has a width-to-depth ratio of 2. The results presented are from simulations of internal waves induced by sloshing a density-stratified liquid. Nonlinear, viscous flow equations of a Newtonian, Boussinesq liquid are solved. Some of the features of the evolution of sloshing in nearly two-layer and three-layer fluid systems are described. Initially, the middle of the two layers and the center of the middle layer of the three layers are horizontal and located at the center of the tank. The two-layer cases are forced at resonance. The evolution of sloshing from rest is examined. The maximum amplitude of sloshing occurs during the initial transient. If breaking occurs, it is at the center of the container in the two-layer cases. The subharmonic forcing of a three-layer case induces a resonant response with the middle layer moving in such a way that motion is perpendicular to the isopycnals within this layer. These model problems provide some insights into the relatively complex sloshing that can occur in density-stratified liquids.
Fatigue Test Data for Welded Connections in Ship-Shaped Structures
Authors: Kim W. S. , Lotsberg I.
Published: November 2005

Five different specimens representing different typical welded connections in ship-shaped structures were fatigue-tested by HHI in Korea. The test data from the five different specimens for one loading condition were transferred into one hot spot S-N diagram. It was observed that two of the data series plotted rather high in the S-N diagram as compared with the other three test series. The reason for this was questioned. It was decided to test a few specimens at another test laboratory for verification of the test data. The same types of specimens were fabricated by HHI and shipped to Oslo and fatigue-tested in the laboratories of DNV. The results from this fatigue testing are presented in this paper in addition to the original fatigue test data from HHI.
Assessment of Fatigue Safety Factors for Deep-Water Risers in Relation to VIV
Authors: Leira Bernt J. , Meling Trond Stokka , Larsen Carl M. , Berntsen Vidar , Stahl Bernie , Trim Andrew
Published: November 2005

Safety factors required to control fatigue damage of deepwater metallic risers caused by vortex-induced vibration (VIV) are considered. Four different riser configurations are studied: Cases I and II: Vertical tensioned 12in. risers suspended from a spar buoy at water depths of 500 and 1500m. Cases III and IV: Steel catenary risers suspended from a spar buoy, both at 1000m. For Case III, the riser diameter is 12in., while for Case IV it is 33in. For each riser configuration, relevant design and analysis parameters which are subject to uncertainty are identified. For these quantities, random variables are established also representing model uncertainties. Subsequently, repeated analyses of fatigue damage are performed by varying the input parameters within representative intervals. The results are applied to fit analytical expressions (i.e., so-called response surfaces) utilized to describe the limit state function and to develop the probabilistic model for reliability analysis of the risers. By combining the random variables for the input parameters with the results from the parameter variations, a relationship between the fatigue safety factor and the failure probability is established for each riser configuration.
Sounds of the Bagpipe
Authors: Harris Cyril M. , Eisentadt Maurice , Weiss Mark R.
Published: November 2005

An analysis has been made of the sounds of a Highland bagpipe played by a professional piper. This instrument consists of a leather bag fitted with five pipes: the blowpipe, through which the player fills the bag with air; the chanter, which has eight open holes on which the melody is played; and the outer tenor drone, middle tenor drone, and bass drone, which produce harmonious steady tones. Spectral analyses were made of each of the drones and the chanter by sounding separately, in various combinations, and under normal playing conditions. The harmonic structure of these sounds was investigated as a function of a number of parameters, including blowing pressure, length of drone, and type of reed. Transient, as well as steady-state, conditions were investigated. These results are presented, together with a live demonstration of sounds of the bagpipe.
Significant Characteristics of Good Violins and Other Wooden Musical Instruments
Authors: Skudrzyk Eugen J.
Published: November 2005

The acoustical characteristics of musical instruments depend greatly on the material from which they are constructed. In wood, damping for transverse vibrations is relatively low at low frequencies and increases relatively rapidly at the higher frequencies. As a consequence, wooden instruments have relatively pronounced low-frequency transients and are low in high-overtone content. Because of their pronounced transients. they can be easily located in the orchestra; their sound is soft and agreeable because of the damped high overtones. Old wood has particularly low damping at low frequencies, and more damping than recent wood at higher frequencies. Because of the low damping at low frequencies, old violins usually have much better carrying power than new violins. Varnishing increases the damping at high frequencies and may render new instruments soft and agreeable, but it cannot make up for the greater carrying power of the older instruments. Since the main feature of a good violin is its carrying power in the orchestra, judgment of individual violins in solo leads necessarily to wrong conclusions. It is not accidental that bell metal has absorption characteristics similar to those of wood. Interesting experiences with musical instruments are discussed in this paper.
Transients in Wood Winds and Brasses
Authors: Neustadt Herbert M.
Published: November 2005

An interesting transient effect occurs in a flute, or other wind musical instrument, when it plays in sequence two tones that are more than a semitone apart in pitch. If the pitch change is made abruptly (1) tone generation decreases and may stop momentarily even if air supply is held constant at the mouthpiece—that is, oscillation decays at the old frequency and then builds up again at the new; (2) the ear does not perceive that oscillation is interrupted; (3) if the pitch change were made without the interruption—that is, at constant amplitude—a click would be heard accompanying the pitch change. These statements are demonstrated by means of an electronic device. The transient behavior of the wind instruments is analyzed by use of equivalent circuits in which the mouthpiece is represented as a negative resistance. [This work was supported by the John Simon Guggenheim Memorial Foundation and the U. S. Office of Naval Research.]
Acoustic Parameters of Violin Design Applied to the Development of a Graduated Series of Violin-Type Instruments
Authors: Htchins Carleen M.
Published: November 2005

The static situation among the strings since Bach's time has fostered a great musical literature. Information is now available for a reconsideration of the possibilities of string instruments, both in relation to a practically unheard body of early music and to music of the future. Findings in present violin research are discussed in relation to the development of a self-consistent choir of eight violin-type instruments covering approximately piano range; placement and relationship of main wood and air resonances in the violin itself; “tap tone” relationships in free top and backplates to produce desired tone quality in a finished instrument; methods of putting resonances at desired frequencies for a given instrmnent; dimensional scaling based on the violin; clues to characteristic tone production as found in German and Italian methods of violin making.
Patterns of Ratio Relationships in Melody
Authors: Boomsliter Paul C. , Creel Warren
Published: November 2005

Musicians selected their preferred tunings for specific melodies, using an instrument that allows choice of intonation. In this critical listening situation, their choices were found to represent a number of variations on a principle of organization by simple whole-number ratios to tonal centers. Even without modulation, these melodic choices shift away from direct relation to the tonic to relation to other tonal centers. These acting tonal centers stand in small-whole-number ratios to other centers, which in turn have the same class of relation to the tonic. The instances presented do not match any known scale; they indicate structural importance for variant tunings of the same note, and for what is here called “extended reference,” a tendency to avoid direct relationship to the tonic until resolution is desired. Thus, they indicate that tuning preferences are the result of the operation of structural principles embodied in a melody rather than in a scale.
Temperament Habits and Preferences of Professional Musicians
Authors: Stauffer Donald W.
Published: November 2005

It is usually claimed by students of musical temperament that equal temperament is the only feasible one with a fixed 12-note system. Artist musicians, however, not infrequently insist from an empirical viewpoint that equal temperament is inferior, implying that they use some sort of superior artistic scale in their performance. This study is undertaken to determine, by the repeated measurements of musical intervals in differing contexts, just what the preferences and tendencies of professional musicians are, and what relationship they have to equal temperament or any other scale context. The first study in this series will attempt to measure the use of the major third, which is, of course, the most important and strategic color interval in our musical system. Repeated renditions of this interval will be measured against a standard tempered major third in an effort to form conclusions as to musicians' preferences under varying musical situations.
Attenuation of High-Amplitude Sound Pulses in Water
Authors: Howkins S. D.
Published: November 2005

A new technique for measuring the peak pressure of a high-amplitude sound pulse travelling through a liquid is described. The method involves a photometric measurement of the amount of carbon transferred, under the influence of the pulse, from a piece of carbon-coated paper to a piece of white “printing-out paper.” Results were obtained in this way for the attenuation of pulses, having peak pressures of up to 700 atm, as they travel through a column of water contained in a rigid tube. These are compared with a simple theory in which the pulse is assumed to have a shape approximating that of a right-angle triangle.
Harmonic Analysis of the Scattered Pressure Field from a Single Bubble
Authors: Connolly C. C. , Nyborg W. L.
Published: November 2005

Pressure measurements were made on the first- and second-harmonic pressure fields scattered from single bubbles stable in a 20-kc/sec sound field at ambient-pressure amplitudes PA up to about 0.8 atm. The second-harmonic amplitude p2 proves to be a sensitive indicator of bubble behavior. Though p2 is usually an increasing function of PA at low amplitudes, tending to rise as PA2, pronounced exceptions are noted. Critical ranges of PA exist where p2 decreases, then increases rapidly, with increasing PA. In a critical range, obvious hissing occurs; in visual observations, a number of “microbubbles” (i.e., bubbles of diameter ≃15 μ or less) are seen near the original bubble. These microbubbles are generated when vigorous surface modes are set up on the original bubble, as described earlier by Willard. When PA increases to values of the order of 0.8 atm, the amplitudes of both first and second harmonics appear to approach limiting values, while higher harmonics and a subharmonic appear. A theory for the second harmonic was derived, assuming successive approximations to the Noltingk-Neppiras equation. The result for p2 is of the form DPA2, where D depends on frequency and bubble radius. [Supported in part by NIH Grant RG-8209.]
Circadian Variability of Auditory Threshold
Authors: Ward W. Dixon
Published: November 2005

Recently, Neuberger and Schmid [Archiv Ohren- Nasen- u. Kehlkopfheilk. ver. Z. Hals- Nasen- u. Ohrenheilk. 179, 237-258 (1962)] reported that the auditory threshold shows a circadian (diurnal) variability, being 10–15 dB higher (less sensitive) at midnight than at noon. Because of the drastic implications of this result for any longitudinal studies of hearing, a short study to test its validity was run. Six subjects were tested at 0.5, 1, 2, 3, 4, and 6 kc/sec by using interrupted tone, and at 1 kc/sec by using continuous tone (Békésy technique), at 8 A.M., 1 P.M., 5 P.M., and 11 P.M., for 4 days. No significant differences among the thresholds obtained at different times of day were found, either for the group or for any individuals. It is therefore concluded that the results of Neuberger and Schmid are due to some sort of artifact, and that (as we have always assumed) one need not worry about time of day per se in studies involving repeated testing of the same individuals. Some speculations about the nature of Neuberger and Schmid's artifact are offered.
Analysis of Acoustic Speech Signals into Articulatory Parameters
Authors: Heinz John M.
Published: November 2005

An analysis technique is discussed whereby speech spectra are compared with spectra generated by a computer-simulated model of articulation. In this model, a spectrum is determined by specifying as input parameters a vocal-tract area function (or a simplified configurational description) and the source spectral envelope and location. The input parameters are adjusted to obtain a “spectral match” between the internally generated spectrum and the speech spectrum, thereby specifying the articulatory parameters that correspond to the given speech spectrum. Data relating to matches from several classes of speech sounds are presented. Questions pertaining to the uniqueness and applicability of the parameters obtained by this procedure are discussed, with particular reference to descriptions of vocal-tract dynamics. The possibility of using parameters derived by this technique to control a dynamic vocal-tract analog synthesizer is also considered. [This work was supported in part by the U. S. Army, the U. S. Air Force Office of Scientific Research, and the U. S. Office of Naval Research; in part by the U. S. Air Force (Electronic Systems Division) under Contract AF 19(604)-6102; in part by the National Science Foundation (Grant G-16526); and in part by the National Institutes of Health (Grant MH-04737-02).
Modeling Speech for Economical Communication
Authors: David Edward E.
Published: November 2005

The conventional model of speech acoustics postulates a sequence of quasi steady-state spectra. The spectral shapes can be related rather precisely to the transfer response of the appropriate vocal-tract configurations. Less is known about the spectral dynamics. These must, however, be related to vocal-tract dynamics that, in turn, must arise from the phonetic and linguistic substrate. Efforts to make these relations concrete face formidable difficulties both from mathematical and data-acquisition standpoints. However, some progress has been made in this quest, which seems a prerequisite to distilling features meaningful for human communication from the speech continnum.
Experimental Study of Noise Reduction in Centrifugal Blowers
Authors: Embleton T. F. W.
Published: November 2005

Several centrifugal blowers with forward, backward, and radial blades have been studied experimentally at various speeds, capacities, and pressures. Attention was concentrated on the methods of noise reduction that are applicable to blowers of any type. It is shown that sound at the blade-passage frequency and its harmonics may be reduced as much as 12 dB either by locating the cutwater at the optimum clearance from the impeller (0.17 in. in the particular blower described), or by sloping the edge of the cutwater relative to the tips of the impeller blades. These two effects on sound-pressure level are additive. Broadband aerodynamic noise originating within the impeller may be reduced 1 or 2 dB by twisting of the impeller blades. For the proper amount and direction of the twist, this latter noise-control measure also results in an improvement of mechanical efficiency (up to 10 %), though at the expense of decreased capacity (typically 5% to 10%). Further noise reduction is achieved only with decreased efficiency.
Transistor Microphone
Authors: Sikorski M. E.
Published: November 2005

The current-voltage characteristics of junction transistors undergo a shift when certain sets of stresses are applied to the transistor body. Results of application of hydro-static, uniaxial, and localized or “point” stresses to transistors are presented. An emphasis is placed on the effects of localized stresses on various regions of the transistor. These effects are due to stress modulation of current flow across the p-n junctions. A microphone was built that utilizes some of the abovementioned phenomena. The experimental transistor microphone exceeded the performance characteristics of a carbon transmitter in sensitivity, electrical efficiency, and signal-to-noise ratio. Its frequency response was comparable to that of the carbon microphone due to the fact that a carbon-transmitter diaphragm was used. The discussion includes the methods of electrical biasing, as well as the influence of a few transistor parameters, such as breakdown voltage and current gain, on the performance of the microphone.
Sensory Thresholds and Response Bias in the Detection of Auditory Signals
Authors: Norman Donald A.
Published: November 2005

Responses in an auditory-detection experiment are assumed to be determined in two stages: a detection stage, in which the auditory signal is transformed into some physiological representation, and a decision stage, in which the response is generated, using the output of the detection process and the observer's motivations and expectations, as well. Three models for detection of an auditory signal are considered: a low-threshold model, the neural quantum theory, and a continuous model, signal-detectability theory. Several decision models are applied to the detection models, and their predictions for psychometric functions and ROC curves in yes-no and temporal forced-choice experiments are examined, both theoretically and experimentally. Although the experiments use as a signal a brief increment in the amplitude of a sinewave, the models are not restricted to this situation. The decision model applied to the neural quantum theory provides an explanation for the way in which the psychometric functions of quantum theory are transformed into nearly ogival functions by changes in experimental procedure. The experiments strongly support the existence of a low differential threshold by all measures examined: the locations of the ROC curves, the characteristics of the psychometric functions, and the shape of the temporal forced-choice ROC curves.