bluuebunny/crossref_metadata_2025 huggingface dataset:
First adaptive optics control of laser beam based on interferometric phase-front detection
Authors: Avino S. , Calloni E. , Baker J. T. , Barone F. , DeRosa R. , DiFiore L. , Milano L. , Restaino S. R.
Published: August 2005

We present an adaptive optics (AO) system for the control of geometrical fluctuations in a laser beam based on the interferometric detection of phase front. By comparison with the usual Shack–Hartmann and phase diversity based AO systems, we show that this technique is of particular interest when high sensitivity and high bandpass are required for correction of small perturbations like, for instance, the control of the input laser beam of gravitational waves interferometric detectors.
Current-induced colossal electroresistance in p-n heterostructure of La0.67Ca0.33MnO3−δ and Nb-doped SrTiO3
Authors: Zhang X. P. , Xie B. T. , Xiao Y. S. , Yang B. , Lang P. L. , Zhao Y. G.
Published: August 2005

We report the colossal negative electroresistance (ER) in the p-n heterostructure of La0.67Ca0.33MnO3−δ (LCMO) and Nb-doped SrTiO3. For a vacuum-annealed sample, a maximum ER of 4×104% can be reached by 1 mA current and magnetic field has remarkable influence on the ER of the sample. It is interesting that the magnetoresistance of the heterostructure can also be tuned by electric current. The results were explained by the current shunting model. In this scenario, the current shunting is determined by the resistance of LCMO and the junction resistance. On the other hand, the resistance of LCMO and the junction resistance are also affected by current. The interaction of these factors can tune the electrical transport of the heterostructure dramatically. This work shows that manganites combined with other materials can result in some interesting properties that may have potential applications.
Performance of 2 nm gate length carbon nanotube field-effect transistors with source∕drain underlaps
Authors: Alam Khairul , Lake Roger
Published: August 2005

The performance of coaxially gated, zero-Schottky-barrier, carbon nanotube field-effect transistors is investigated for gate lengths down to 2 nm with source and drain underlaps. Such devices can have nearly ideal subthreshold slopes of ∼63mV∕dec and maximum on∕off current ratios of 2.2×106 assuming 0.0–0.4 volt swing. The leakage mechanism is a combination of both intra-band and inter-band tunneling. For a 30 nm long carbon nanotube (CNT) with a 2 nm gate, Cg=3.13aF, the intrinsic switching time, τs=CgVDD∕ION, is 370 fs, and the intrinsic cut-off frequency defined by fT=gm∕(2πCg) is 1.6 THz. The ambipolar leakage current is suppressed by Coulomb blockade. Calculations are performed using a π-bond model and a self-consistent solution of the nonequilibrium Green function equations and Poisson’s equation.
Low-resistance Au and Au∕Ni∕Au Ohmic contacts to p-ZnMgO
Authors: Ip Kelly , Li Yuanjie , Norton D. P. , Pearton S. J. , Ren F.
Published: August 2005

Both electron-beam-deposited Au and Au∕Ni∕Au are found to produce low-resistance Ohmic contacts (ρC in the range 2.5×10−5–7.6×10−6Ωcm2) to p-type ZnMgO (p∼1016cm−3) on sapphire substrates after annealing at 600°C. The as-deposited contacts are rectifying in both cases. For the Au contact, the annealing produces a small amount of outdiffusion of Zn to the surface of the contact, whereas with the Au∕Ni∕Au, both Ni and Zn are found on the surface. In both cases, the formation of Zn vacancies may play a role in increasing the near-surface hole concentration in the ZnMgO.
Effect of 90° domain movement on the piezoelectric response of patterned PbZr0.2Ti0.8O3∕SrTiO3∕Si heterostructures
Authors: Ma Zhengkun , Zavaliche F. , Chen L. , Ouyang J. , Melngailis J. , Roytburd A. L. , Vaithyanathan V. , Schlom D. G. , Zhao T. , Ramesh R.
Published: August 2005

The converse longitudinal piezoelectric responses of PbZr0.2Ti0.8O3∕SrTiO3∕Si heterostructures have been studied for continuous films and for islands patterned by focused ion beam milling (typical dimension is 1×1×1μm). The intrinsic piezoelectric response of the island with an immobile polydomain structure is modeled using finite element analysis. The difference between the results of experimental measurement and modeling is explained by an extrinsic contribution to the piezoresponse from 90° domain movement. The contribution of 90° domain movement to the total piezoresponse is shown to be greatly enhanced in the patterned islands, and leads to an effective piezoelectric coefficient (∼400pm∕V) which is five times larger than the theoretical bulk single domain value.
High drain current density and reduced gate leakage current in channel-doped AlGaN∕GaN heterostructure field-effect transistors with Al2O3∕Si3N4 gate insulator
Authors: Maeda Narihiko , Wang Chengxin , Enoki Takatomo , Makimoto Toshiki , Tawara Takehiko
Published: August 2005

Channel-doped AlGaN∕GaN heterostructure field-effect transistors (HFETs) with metal-insulator-semiconductor (MIS) structures have been fabricated to obtain the high drain current density and reduced gate leakage current. A thin bilayer dielectric of Al2O3(4nm)∕Si3N4(1nm) was used as the gate insulator, to simultaneously take advantage of the high-quality interface between Si3N4 and AlGaN, and high resistivity and a high dielectric constant of Al2O3. A MIS HFET with a gate length of 1.5μm has exhibited a record high drain current density of 1.87A∕mm at a gate voltage (Vg) of +3V, which is ascribed to a high applicable Vg and a very high two-dimensional electron gas (2DEG) density of 2.6×1013cm−2 in the doped channel. The gate leakage current was reduced by two or three orders of magnitude, compared with that in normal HFETs without a gate insulator. The transconductance (gm) was 168mS∕mm, which is high in the category of the MIS structure. Channel-doped MIS HFETs fabricated have thus been proved to exhibit the high current density, reduced gate leakage current, and relatively high transconductance, hence, promising for high-power applications.
Significant stiffness reduction at ferroelectric domain boundary evaluated by ultrasonic atomic force microscopy
Authors: Tsuji T. , Saito S. , Fukuda K. , Yamanaka K. , Ogiso H. , Akedo J. , Kawakami Y.
Published: August 2005

Two-dimensional resonance frequency mapping in the ultrasonic atomic force microscopy was applied to the investigation of the ferroelectric domain structure in lead zirconate titanate ceramics. This method can visualize the stiffness anisotropy due to the differently oriented domains. Moreover, the significant stiffness reduction at the ferroelectric domain boundary was discovered. The disorder of the lattice, the ability of the switching of the domain, and the reduction of the piezoelectric stiffening are possible explanations. The implication of this work is the characterization of novel functional materials on nanoscale and the nondestructive evaluation of the microelectromechanical systems and nanotechnology devices.
Effect of watertable depth on evaporation and salt accumulation from saline groundwater
Authors: Rose D. A. , Konukcu F. , Gowing J. W.
Published: August 2005

When the evaporative demand is greater than the ability of the soil to conduct water in the liquid phase, the soil profile above a watertable exhibits a liquid−vapour discontinuity, known as the evaporation front, that affects the depth of salinisation and the rate of evaporation. We conducted experiments on a sandy loam with shallow saline watertables under high isothermal evaporative demand (24 mm/day), monitoring rates of evaporation from the soil and upward movement of groundwater, and observing profiles of soil water and salinity over periods of up to 78 days. Three zones were distinguished in the soil profile: a zone of liquid flow above the watertable, a zone of vapour flow close to the surface, and an intermediate transition zone in which mixed liquid−vapour flow occurred. The vapour-flow zone above the evaporation front appeared after a few days and progressed downward to depths of 40, 60, and 120 mm, while eventual steady-state rates of evaporation were 1.3, 1.1, and 0.3 mm/day for watertable depths of 300, 450, and 700 mm, respectively. Salts mainly accumulated in the transition zone, suggesting that the depth of the evaporation front should be a criterion to locate and prevent salinisation as a result of capillary flow from a watertable in arid regions.
Soil puddling for rice production under glasshouse conditions—its quantification and effect on soil physical properties
Authors: Kirchhof G. , So H. B.
Published: August 2005

The effect of soil puddling on soil physical properties of 3 different textured soils (clay, loam, and silty loam) and growth of rice (Oryza sativa) on these soils was investigated under glasshouse conditions. Puddling intensity was expressed as the ratio of soil volume subjected to the puddling implement and the total soil volume in the puddled layer, thus integrating the effects of speed and time of the puddling operation. This parameter was well related to soil dispersion, bulk density, and saturated hydraulic conductivity. However, following prolonged periods of submerged conditions during rice growth, saturated hydraulic conductivity decreased with a decrease in soil dispersion, in contrast to an expected reduction in saturated hydraulic conductivity with increased dispersion. There was indication that continuous waterlogging reduced the effect of soil puddling, in particular on heavy-textured soils.
Comparison of the Instantaneous Profile Method and inverse modelling for the prediction of effective soil hydraulic properties
Authors: Dikinya Oagile
Published: August 2005

Soil hydraulic conductivity K(θ) and soil water retention θ(h) have been determined from a drainage experiment. Two lysimeters, one filled with a sandy soil and the other with a loamy soil, were set up for a 1-dimensional transient flow experiment. The data were collected after flooding the lysimeters with water. Soil water contents were measured by time domain reflectrometry (TDR) and pressure heads were measured by tensiometers with mercury manometers. The experimental data determined by the instantaneous profile method (IPM) were compared with the results obtained by inverse modelling. The inverse modelling proved to be superior to the IPM methodology in effective prediction of hydraulic properties. The measurable properties water content and pressure head were optimised for the following datasets: water content (WC), pressure head (P-h), and a combination of WC and P-h. For both soils the optimisation of the dataset with both WC and P-h resulted in parameters that corresponded closely to the soil hydraulic data generated by the IPM method. The correspondence for the water retention data was better than for the hydraulic conductivity data. The datasets with WC only or P-h only did not contain enough information to accurately estimate the soil hydraulic properties. In most cases the results indicated that the sandy soil gave better agreement than the loamy soil. This was attributed to the faster drainage of the sandy than the loamy soil.
Fire, landscape heterogeneity and wildlife management in Australia's tropical savannas: introduction and overview
Authors: Whitehead Peter J. , Russell-Smith Jeremy , Woinarski John C. Z.
Published: August 2005

Despite an apparent structural integrity, the savanna landscapes of northern Australia are in flux. Important elements of the fauna have contracted in range and are less abundant than in the relatively recent past. Vegetation patterns are changing as populations of some important woody plants decline in some parts of the savannas while, in other places, different trees and shrubs are substantially increasing in density. These sorts of changes are occurring in lands under all tenures and subject to a variety of management goals and practices, including conservation reserves. Fire, large grazing animals and, more recently, invasive plants have all been implicated as drivers of adverse change. An important general, albeit inadequately tested, theory about apparently widespread faunal decline is that these influences have, jointly or separately, compromised landscape heterogeneity. It has been proposed that resource-rich patches that sustain savanna fauna through seasonal and longer-term peaks and troughs have been reduced in number, become more widely separated in space and time, or have been reduced in quality so that wildlife dependent on the rich patches struggle to use them effectively. The issues connected with these ideas were explored in a conference on fire and savanna management at Charles Darwin University in July 2003. Congruent with the theme of the symposium in which they were presented – Managing for Heterogeneity – the subset of papers presented here is diverse in origins, issues, perspectives and the spatial and temporal scales with which they deal. We consider that they make an important contribution to debate about conservation and development in northern Australia. Not because they answer the important questions, but because they illustrate the need for a shift in emphasis: from tentative exploration of pattern and weak inference about process to a harder-edged examination of the features of savanna habitats that influence their capacity to support viable wildlife populations.
Unsupervised learning of natural languages
Authors: Solan Zach , Horn David , Ruppin Eytan , Edelman Shimon
Published: August 2005

We address the problem, fundamental to linguistics, bioinformatics, and certain other disciplines, of using corpora of raw symbolic sequential data to infer underlying rules that govern their production. Given a corpus of strings (such as text, transcribed speech, chromosome or protein sequence data, sheet music, etc.), our unsupervised algorithm recursively distills from it hierarchically structured patterns. Theadios(automatic distillation of structure) algorithm relies on a statistical method for pattern extraction and on structured generalization, two processes that have been implicated in language acquisition. It has been evaluated on artificial context-free grammars with thousands of rules, on natural languages as diverse as English and Chinese, and on protein data correlating sequence with function. This unsupervised algorithm is capable of learning complex syntax, generating grammatical novel sentences, and proving useful in other fields that call for structure discovery from raw data, such as bioinformatics.
Convergent evolution of chemical defense in poison frogs and arthropod prey between Madagascar and the Neotropics
Authors: Clark Valerie C. , Raxworthy Christopher J. , Rakotomalala Valérie , Sierwald Petra , Fisher Brian L.
Published: August 2005

With few exceptions, aposematically colored poison frogs sequester defensive alkaloids, unchanged, from dietary arthropods. In the Neotropics, myrmicine and formicine ants and the siphonotid millipedeRhinotus purpureusare dietary sources for alkaloids in dendrobatid poison frogs, yet the arthropod sources forMantellapoison frogs in Madagascar remained unknown. We report GC-MS analyses of extracts of arthropods and microsympatric Malagasy poison frogs (Mantella) collected from Ranomafana, Madagascar. Arthropod sources for 11 “poison frog” alkaloids were discovered, 7 of which were also detected in microsympatricMantella. These arthropod sources include three endemic Malagasy ants,Tetramorium electrum,Anochetus grandidieri, andParatrechina amblyops(subfamilies Myrmicinae, Ponerinae, and Formicinae, respectively), and the pantropical tramp millipedeR. purpureus. Two of these ant species,A. grandidieriandT. electrum, were also found inMantellastomachs, and ants represented the dominant prey type (67.3% of 609 identified stomach arthropods). To our knowledge, detection of 5,8-disubstituted (ds) indolizidine iso-217B inT. electrumrepresents the first izidine having a branch point in its carbon skeleton to be identified from ants, and detection of 3,5-ds pyrrolizidine 251O inA. grandidierirepresents the first ponerine ant proposed as a dietary source of poison frog alkaloids. Endemic Malagasy ants with defensive alkaloids (with the exception ofParatrechina) are not closely related to any Neotropical species sharing similar chemical defenses. Our results suggest convergent evolution for the acquisition of defensive alkaloids in these dietary ants, which may have been the critical prerequisite for subsequent convergence in poison frogs between Madagascar and the Neotropics.
Vitamin C biosynthesis in trypanosomes: A role for the glycosome
Authors: Wilkinson Shane R. , Prathalingam S. Radhika , Taylor Martin C. , Horn David , Kelly John M.
Published: August 2005

The capacity to synthesize vitamin C (ascorbate) is widespread in eukaryotes but is absent from humans. The last step in the biosynthetic pathway involves the conversion of an aldonolactone substrate to ascorbate, a reaction catalyzed by members of an FAD-dependent family of oxidoreductases. Here we demonstrate that both the African trypanosome,
Trypanosoma brucei
, and the American trypanosome,
Trypanosoma cruzi
, have the capacity to synthesize vitamin C and show that this reaction occurs in a unique single-membrane organelle, the glycosome. The corresponding
T. brucei
flavoprotein (TbALO) obeys Michaelis–Menten kinetics and can utilize both
l
-galactono-γ-lactone and
d
-arabinono-γ-lactone as substrate, properties characteristic of plant and fungal enzymes. We could detect no activity toward the mammalian enzyme substrate
l
-gulono-γ-lactone.
TbALO
null mutants (bloodstream form) were found to display a transient growth defect, a trait that was enhanced when they were cultured in medium in which the essential serum component had been pretreated with ascorbate oxidase to deplete vitamin C. It is implicit, therefore, that bloodstream-form trypanosomes also possess a capacity for ascorbate transport.
An evolutionary constraint: Strongly disfavored class of change in DNA sequence during divergence of cis-regulatory modules
Authors: Cameron R. Andrew , Chow Suk Hen , Berney Kevin , Chiu Tsz-Yeung , Yuan Qiu-Autumn , Krämer Alexander , Helguero Argelia , Ransick Andrew , Yun Mirong , Davidson Eric H.
Published: August 2005

The DNA of functional cis-regulatory modules displays extensive sequence conservation in comparisons of genomes from modestly distant species. Patches of sequence that are several hundred base pairs in length within these modules are often seen to be 80–95% identical, although the flanking sequence cannot even be aligned. However, it is unlikely that base pairs located between the transcription factor target sites of cis-regulatory modules have sequence-dependent function, and the mechanism that constrains evolutionary change within cis-regulatory modules is incompletely understood. We chose five functionally characterized cis-regulatory modules from the
Strongylocentrotus purpuratus
(sea urchin) genome and obtained orthologous regulatory and flanking sequences from a bacterial artificial chromosome genome library of a congener,
Strongylocentrotus franciscanus
. As expected, single-nucleotide substitutions and small indels occur freely at many positions within the regulatory modules of these two species, as they do outside the regulatory modules. However, large indels (>20 bp) are statistically almost absent within the regulatory modules, although they are common in flanking intergenic or intronic sequence. The result helps to explain the patterns of evolutionary sequence divergence characteristic of cis-regulatory DNA.
Tissue morphogenesis and vascular stability require the Frem2 protein, product of the mouse myelencephalic blebs gene
Authors: Timmer John R. , Mak Tracy W. , Manova Katia , Anderson Kathryn V. , Niswander Lee
Published: August 2005

Adhesive properties of cells undergoing morphogenetic rearrangements can be regulated either at the cellular level or by altering the environment in which rearrangements occur. Here, we describe the identification of a mutation (

my
F11

) in the mouse extracellular matrix component Frem2, and provide evidence that suggests Frem2 expression creates an environment conducive to morphogenetic events. Loss of Frem2 function results in defects in developmental events associated with morphogenetic rearrangements of the vasculature and of tissues arising from all germ layers. The Frem2 transcript is restricted both spatially and temporally and appears in advance of cell rearrangement events. Thus, expression of Frem2 may dynamically alter the extracellular matrix to provide a substrate for cell migration and rearrangements during embryogenesis.
Nearsightedness of electronic matter
Authors: Prodan E. , Kohn W.
Published: August 2005

In an earlier paper, W. Kohn had qualitatively introduced the concept of “nearsightedness” of electrons in many-atom systems. It can be viewed as underlying such important ideas as Pauling's “chemical bond,” “transferability,” and Yang's computational principle of “divide and conquer.” It describes the fact that, for fixed chemical potential, local electronic properties, such as the density
n
(
r
), depend significantly on the effective external potential only at nearby points. Changes of that potential,
no matter how large
, beyond a distance R have
limited
effects on local electronic properties, which rapidly tend to zero as a function of R. In the present paper, the concept is first sharpened for representative models of uncharged fermions moving in external potentials, and then the effects of electron–electron interactions and of perturbing external charges are discussed.
Coexistence of multivalent and monovalent TCRs explains high sensitivity and wide range of response
Authors: Schamel Wolfgang W.A. , Arechaga Ignacio , Risueño Ruth M. , van Santen Hisse M. , Cabezas Pilar , Risco Cristina , Valpuesta José M. , Alarcón Balbino
Published: August 2005

A long-standing paradox in the study of T cell antigen recognition is that of the high specificity–low affinity T cell receptor (TCR)–major histocompatibility complex peptide (MHCp) interaction. The existence of multivalent TCRs could resolve this paradox because they can simultaneously improve the avidity observed for monovalent interactions and allow for cooperative effects. We have studied the stoichiometry of the TCR by Blue Native–polyacrylamide gel electrophoresis and found that the TCR exists as a mixture of monovalent (αβγεδεζζ) and multivalent complexes with two or more ligand-binding TCRα/β subunits. The coexistence of monovalent and multivalent complexes was confirmed by electron microscopy after label fracture of intact T cells, thus ruling out any possible artifact caused by detergent solubilization. We found that although only the multivalent complexes become phosphorylated at low antigen doses, both multivalent and monovalent TCRs are phosphorylated at higher doses. Thus, the multivalent TCRs could be responsible for sensing low concentrations of antigen, whereas the monovalent TCRs could be responsible for dose-response effects at high concentrations, conditions in which the multivalent TCRs are saturated. Thus, besides resolving TCR stoichiometry, these data can explain how T cells respond to a wide range of MHCp concentrations while maintaining high sensitivity.
Minimal Access Surgical Techniques in the Management of the Painful Lumbar Motion Segment
Authors: German John W. , Foley Kevin T.
Published: August 2005

Study Design.

Review article.

Objectives.

To provide an overview of current minimally invasive lumbar fusion techniques.

Summary of Background Data.

Minimally invasive lumbar fusion techniques have only recently been developed. The goals of these procedures are to reduce approach-related soft tissue injury while allowing the surgery to be conducted in an effective manner.

Methods.

Pertinent literature and the authors’ clinical experience are reviewed.

Results.

Minimally invasive techniques have been developed for intertransverse process, posterior lumbar interbody, and transforaminal lumbar interbody fusions. The indications, advantages, and disadvantages of each technique are described. It is emphasized that while they appear promising, the clinical results of these techniques remain preliminary with few long-term studies available for critical review.

Conclusions.

Preliminary clinical evidence suggests that minimally invasive lumbar fusion techniques will benefit patients with spinal disorders.
Indications for Surgical Fusion of the Cervical and Lumbar Motion Segment
Authors: Bambakidis Nicholas C. , Feiz-Erfan Iman , Klopfenstein Jeffrey D. , Sonntag Volker K. H.
Published: August 2005

Study Design.

A literature review and the authors’ clinical experience for the indication of fusion in the degenerative lumbar and cervical spine is provided.

Objective.

To establish absolute and relative criteria for the indication for fusion in the degenerative cervical and lumbar spine.

Summary of Background Data.

Fusion in the cervical and lumbar degenerative spine is indicated under certain strict criteria. However, fusion in circumstances not meeting these criteria is controversial.

Method.

A review of the literature and the authors’ experience concerning indication and criteria of fusion in degenerative, lumbar, and cervical spine is provided.

Results.

Fusion for the unstable spine related to trauma, infection, and tumors is relatively accepted. However, indications for fusion for degenerative, cervical, and lumbar spine are more controversial.

Conclusion.

Lumbar and cervical fusion in the degenerative spine is frequently performed. Certain criteria have been established when a fusion should be considered. However, even these are not universally accepted. Strict prospective studies are needed to determine when a fusion of the degenerative, cervical, and lumbar spine is indicated. Patients with severe radicular pain may be considered for surgery after a comprehensive trial of conservative management. Fusion is usually necessary after a cervical discectomy, especially when spondylosis or osteophytic compression is present. Lumbar fusion is rarely indicated for routine discectomy. In patients with mechanical back or neck pain, surgery should only be considered after conservative measures have been exhausted and a radiographic abnormality is present at the symptomatic level, perhaps with pain concordant with discographic findings. Careful patient selection is the key to obtaining favorable surgical outcomes. In many cases, the goal may be a return to functionality rather than achieving a completely asymptomatic state.
Current Treatment Strategies for the Painful Lumbar Motion Segment
Authors: Wang Jeremy C. , Mummaneni Praveen V. , Haid Regis W.
Published: August 2005

Study Design.

Review of the literature.

Objectives.

We discuss the indications and contraindications for posterolateral lumbar fusion and posterior approaches to lumbar interbody fusion. We also review the advances in minimal access surgical techniques, graft materials, and osteobiologics.

Summary of Background Data.

Previously published data and our own surgical experience form the basis of this report.

Methods.

A Pub Med online internet search for the keywords was performed. The pertinent articles were then cited.

Results.

Posterior interbody fusion techniques have theoretical and demonstrable advantages over posterolateral fusion, but the former is also associated with greater morbidity. There are several approaches one may use to perform posterior interbody fusion, as well as multiple minimally invasive techniques and interbody spacer graft options. Bone morphogenetic protein offers an attractive alternative for achieving fusion.

Conclusion.

Fusion of painful motion segments is widely used to treat patients with degenerative low back pain. Successful arthrodesis may be achieved using either posterolateral fusion with pedicle screw fixation or posterior interbody fusion, depending on the patient's situation. These techniques may be accomplished with a variety of minimal access strategies and various graft and spacer technologies. The modern spine surgeon should be proficient in using all these options to treat the painful lumbar motion segment.
Are Somatostatin Analogs Therapeutic Alternatives in the Management of Head and Neck Paragangliomas?
Authors: Duet Michele , Guichard Jean Pierre , Rizzo Nathalie , Boudiaf Mourad , Herman Phillippe , Tran Huy Patrice
Published: August 2005

Background: Although mostly benign, head and neck paragangliomas require active management because of injury to adjacent neurovascular structures. Surgery, usually preceded by embolization, allows for complete tumor removal. However, surgery carries a significant risk of iatrogenic injury, related to tumor volume. Because paragangliomas express somatostatin receptors with high density, we investigated the effect of a long‐acting somatostatin analogue (OCT‐LAR) on the size of such tumors to reduce iatrogenic injury and related the percentage of tumor shrinkage to a tracer uptake index calculated on somatostatin receptor scintigraphy (SRS).

Methods: In eight of the first nine patients, 30 mg of OCT‐LAR was given intramuscularly every 28 days for 3 doses; one patient withdrew after the first dose because of side effects. Conventional imaging with computed tomography (CT) scan or magnetic resonance imaging plus SRS revealed 18 paraganglioma sites. For each lesion, a tracer uptake index was calculated on pretreatment SRS. All 18 tumors were measured by CT scan before treatment and 1 month after the third injection.

Results: The average percent tumor shrinkage was 4.0 ± 10.0%, and the average tumor reduction was 1.0 ± 3.8 cm3 (P = .27, NS). Only 2 of the 18 paragangliomas shrank by more than 20%; these two tumors belonged to the only one secreting patient. There was no significant relation between tracer uptake index and tumor response.

Conclusion: These results suggest 1) that SRS results do not predict OCT‐LAR efficacy on paraganglioma size, and 2) OCT‐LAR is not useful in the preoperative management of paragangliomas.
Supraglottic Laryngeal Cancer: Analysis of Treatment Results
Authors: Sessions Donald G. , Lenox Jason , Spector Gershon J.
Published: August 2005

Objective: This study reports the results of treatment for supraglottic laryngeal cancer with nine different treatment modalities with long‐term follow‐up.

Study Design: Retrospective study of 653 patients with supraglottic laryngeal squamous cell cancer treated from April 1955 to January 1999.

Methods: The study population included previously untreated patients with cancer of the supraglottic larynx treated with curative intent by one of nine treatment modalities and who were eligible for 5‐year follow‐up. The treatment modalities included subtotal supraglottic laryngectomy (SSL), SSL with neck dissection (SSL/ND), total laryngectomy (TL), TL/ND, radiation therapy (RT), SSL/RT, SSL/ND/RT, TL/RT, and TL/ND/RT. Multiple diagnostic, treatment, and follow‐up parameters were studied using standard statistical analysis to determine significance.

Results: None of the nine treatment modalities produced a survival advantage, either overall or within the stages. Overall disease specific survival (DSS) by treatment modality included SSL 88.9%, SSL/ND 75.8%, TL 83.3%, TL/ND 66.7%, RT 47.2%, SSL/RT 68.9%, SSL/ND/RT 68.1%, TL/RT 59.3%, and TL/ND/RT 46.7%. Improved DSS and cumulative disease specific survival rates were associated with patients under the age of 65 years (P = .0001), early stage disease, N0 disease (P = .0001), clear resection margins (P = .0094), and no recurrence (P = .0001). Posttreatment function showed that 90% of patients were functional in everyday life, 90.7% were eating satisfactorily, 91.4% were breathing naturally, and 83% of SSL patients, 85.7% of RT patients, and 52.8% of TL patients had “good” voices. Laryngeal preservation was accomplished in 86.1% of SSL patients and 72.7% of RT patients (P = .0190).

Conclusions: No treatment modality produced a survival advantage. Because SSL produced the best rate of laryngeal preservation, we recommend its use in treating the primary in eligible patients. The importance of clear resection margins is stressed. Patients with N+ disease should have the neck treated. Patients with N0 disease may be observed safely with no loss of survival advantage. Because of the pattern of recurrence and the high rates of distant metastasis and second primary cancers, follow‐up for a period of not less than 8 years is recommended.
The Magnanimous Professional Life and Tragic Demise of J. H. Douglas, MD
Authors: Bentz Brandon G. , Strong Elliot W. , Woodson Gayle E. , Shah Jatin P.
Published: August 2005

Objectives/Hypothesis: Many of the hallmarks of a very successful medical career, such as recognition as a leader in a field of medicine, making important contributions to medical knowledge of the day, and a steadfast dedication to patient care, had already been achieved by Dr. John Hancock Douglas. Therefore, the mystery surrounding his dismissal from membership of the newly formed American Laryngology Society (now the ALA) and his tragic demise stand in stark contrast. We discuss the model professional life and mysterious but tragic final days of this very important laryngologist of the 19th century.

Study Design/Methods: A historical vignette.

Results: Dr. Douglas's professional qualities of leadership of the American Sanitary Commission, his various contributions to the advancement of medical knowledge during that era, and his steadfast dedication to the care of his patients represent highlights of a very honorable professional career. His final demise, bankrupt, in an ill state of health, and stripped of his professional appointment to the ALA, seems an unjust end to the life of this notable and magnanimous laryngologist.

Conclusions: We offer this historical review of the life and demise of Dr. John H. Douglas as a tribute to this important figure in our profession's history.
Creation of a Cholesteatoma Model using Three‐Dimensional Cultured Skin Equivalents
Authors: Tanaka Yasuhiro , Yaguchi Yuichiro , Wada Kota , Kojima Hiromi , Moriyama Hiroshi
Published: August 2005

Objectives/Hypothesis: Recent years have seen success in establishing methods for cell culture that lead to the creation of a three‐dimensional tissue architecture, and this represents a great advance for the ability to carry out research in vitro. Accordingly, the present studies were carried out with the objective of using three‐dimensional cultured skin equivalents for the in vitro creation of a model of middle ear cholesteatoma, something that has heretofore been considered to be very difficult.

Study Design: A cholesteatoma model was created in vitro, and discussion is presented regarding the immigration theory and the retraction theory that have been proposed as explanations of the causation of cholesteatoma.

Methods: Cultured skin equivalents were prepared, followed by creation of an epidermal and dermal defect in them. Then, the changes in the epidermis were investigated histologically. In addition, immunohistochemical studies were performed with regard to the effects exerted on the epidermis when the skin equivalents were cultured in a retracted state.

Results: It was confirmed that, as a result of the defect in the epidermis and dermis of the cultured skin equivalents, the epidermis at the edge of the defective site migrated subepidermally, and a stratified structure was formed. On the other hand, the retraction of the epidermis and dermis exerted almost no effect on the epidermal cells themselves.

Conclusions: These results lend credence to the immigration theory as an explanation of the growth of the epidermis from the defective site. Conversely, it was surmised that the retraction theory requires some other factors in addition to retraction.
Effect of Comorbidity on Quality of Life and Treatment Selection in Patients with Squamous Cell Carcinoma of the Head and Neck
Authors: Gourin Christine G. , McAfee William J. , Neyman Kimberly M. , Howington Jed W. , Podolsky Robert H. , Terris David J.
Published: August 2005

Objectives: Comorbidity is significantly associated with diminished survival and quality of life (QOL) after treatment of head and neck squamous cell carcinoma (HNSCC). We sought to determine whether comorbidity influenced pretreatment QOL scores and treatment selection in patients with HNSCC.

Methods: The medical records of all patients diagnosed with HNSCC who participated in pretreatment QOL analysis over a 15‐month period were retrospectively reviewed. Patients with a history of prior treatment for head and neck cancer, unresectable, or distant metastatic disease were excluded. The University of Washington (UW) QOL questionnaire, Performance Status Scale (PSS), and Karnofsky score were used to measure pretreatment QOL. Comorbidity was graded using the Modified Medical Comorbidity Index.

Results: Of 75 patients who met study criteria, 33 underwent primary surgical therapy, and 42 underwent nonoperative (radiation or chemoradiation) therapy. Treatment groups did not differ with respect to patient demographics, UW QOL scores, PSS scores, Karnofsky score, or comorbidity. Treatment groups differed significantly by disease stage and primary site. Patients with advanced stage disease (III/IV) or oropharyngeal primary tumors were more likely to undergo nonoperative treatment, compared with patients with early stage disease (I/II) or oral cavity primary tumors (P < .005). No significant association was found between comorbidity and pretreatment QOL scores.

Conclusions: Comorbidity was not significantly associated with treatment selection or pretreatment QOL scores in patients with HNSCC. Location of the primary tumor and disease stage were significantly associated with treatment selection. Further studies are required to determine the effect of comorbidity on patient and tumor responses to treatment.
Vocal Cord Paralysis after Laryngeal Mask Airway Ventilation
Authors: Chan Teresa V. , Grillone Gregory
Published: August 2005

The laryngeal mask airway (LMA) is being used with increasing frequency since its introduction into the United States in 1991. Currently, the LMA is being used in the United States in approximately one third of all operations or greater than 100 million surgeries. In Britain, where it was first introduced for use in 1988, the LMA is estimated to be used in up to 50% of cases. Not only has its use in elective cases increased, but the scope of indications for the LMA has also grown. Its use in emergent and difficult airway management has increased, and new LMA products have been introduced to address the limitations of the classic model. As the LMA has increased in popularity, however, so has the incidence of LMA‐related complications. Cases of mucosal trauma, hematoma, tongue cyanosis, arytenoid dislocation, and lingual, hypoglossal, and recurrent laryngeal nerve paralyses have been documented in various anesthesia journals. Reports of these injuries are sparse in the otolaryngology literature. As otolaryngologists who will manage the sequelae of LMA‐related injuries, we must remain cognizant of potential problems and their underlying mechanisms. We report a case of unilateral vocal cord paralysis, which required operative repair after the use of an LMA. We review the existing case reports, propose mechanisms of injury, and discuss practical applications of our findings.
A Single Therapy for All Subtypes of Horizontal Canal Positional Vertigo
Authors: Chiou Wen‐Yaw , Lee Hui‐Ling , Tsai Shih‐Che , Yu Tu‐Hsueh , Lee Xin‐Xian
Published: August 2005

Objective: To demonstrate that a single therapy is effective for treating all subtypes of horizontal canal benign paroxysmal positional vertigo (HC‐BPPV).

Study Design: Prospective study.

Methods: Patients with HC‐BPPV (n = 89) were diagnosed when the supine to the head‐lateral test resulted in geotropic or ageotropic bilateral horizontal nystagmus. Three subtypes of HC‐BPPV were defined by their characteristic patterns of nystagmus as well as by their speculative mechanism. Canalolithiasis (Can) denotes geotropic nystagmus induced by free‐moving otoliths in the HC. Two forms of cupulolithiasis, characterized by otoliths attached either on the utricle‐sided (Cup‐U) or the canal‐sided (Cup‐C) cupula, were identified by whether ageotropic nystagmus resolved or changed to geotropic nystagmus on follow‐up tests. Forced prolonged position (FPP), lying on the healthy side for 12 hours to easily move free otoliths to the utricle, has proven successful in treating Can. Although Cup‐U and contralateral Cup‐C were associated with the same positional nystagmus pattern, FPP with lying on the side of the weaker nystagmus was found to be effective treatment, as well as consistent with the speculated underlying mechanism.

Results: All HC‐BPPV patients including 49 with Can, 11 with Cup‐C and 29 with Cup‐U had complete resolution of symptoms and positional nystagmus after less than four treatment sessions.

Conclusions: FPP with lying on the side of the weaker nystagmus, combined with careful observation of nystagmus evolvement, was found to be effective treatment for all subtypes of HC‐BPPV in this series.
High‐Quality Video Recording and Monitoring System for Endoscopes
Authors: Tsunoda Koichi , Tsunoda Atsunobu , Ozawa Hiroyuki , Fujimine Takekatsu
Published: August 2005

We have developed a new recording system for endoscope images with the popular mini digital video (mini DV) camera. A special adaptor screws onto the lens top, and either a flexible or rigid endoscope can be attached to the camera. Using this system, we can monitor not only the endoscopic images but also the patient's condition. Satisfactory images can be obtained even with the finest fiberscope. Nevertheless, our new system costs only $1,000. Therefore, the system is both cost‐effective and useful for the outpatient clinic or casual setting or for house calls for the purpose of patient education.
Electrical Taste Thresholds Established on the Medial Tongue using Two Sizes of Electrodes
Authors: Nicolaescu Serban A. , Wertheimer Jaclyn M. , Barbash Scott E. , Doty Richard L.
Published: August 2005

Objectives/Hypothesis: The present study determined whether a 125 mm2 electrode would produce lower and more reliable electrical taste thresholds than a 25 mm2 electrode when measurement occurred in a medial tongue region relatively sparse in taste bud numbers. We hypothesized this would be the case and that the obtained threshold values would be higher than those previously reported for anterior and lateral tongue regions.

Study Design And Methods: Sixteen college‐age subjects were tested twice, once using the 25 mm2 electrode and once using the 125 mm2 electrode on each of two sessions separated by 2 to 16 days. The order of presentation of the sessions was counterbalanced across subjects. Measurement was confined to the medial tongue, 0.7 cm lateral to the median furrow.

Results: As hypothesized, the larger electrode resulted in lower and more reliable threshold values than the smaller electrode (respective median threshold values = 20.06 μA & 33.59 μA, P = .001; respective test‐retest rs = 0.78 [P < .001] and 0.46 [P < .05]). Also as hypothesized, the threshold values were higher (i.e., sensitivity lower) than previously reported for anterior and lateral tongue regions.

Conclusions: The magnitude and reliability of electrical taste thresholds depends on the tongue region examined and the size of the electrodes used. These results suggest that relatively large electrodes should be considered for electrogustometric threshold testing, particularly when lingual regions not highly populated with taste buds are evaluated.
Modelling predation as a capped rate stochastic process, with applications to fish recruitment
Authors: James Alex , Baxter Paul D , Pitchford Jonathan W
Published: August 2005

Many mathematical models use functions the value of which cannot exceed some physically or biologically imposed maximum value. A model can be described as ‘capped-rate’ when the rate of change of a variable cannot exceed a maximum value. This presents no problem when the models are deterministic but, in many applications, results from deterministic models are at best misleading. The need to account for stochasticity, both demographic and environmental, in models is therefore important but, as this paper shows, incorporating stochasticity into capped-rate models is not trivial. A method using queueing theory is presented, which allows randomness and spatial heterogeneity to be incorporated rigorously into capped rate models. The method is applied to the feeding and growth of fish larvae.
Optical crossover phenomenon due to a central 90°-twist defect in a chiral sculptured thin film or chiral liquid crystal
Authors: Wang Fei , Lakhtakia Akhlesh
Published: August 2005

We present a theoretical analysis of a remarkable phenomenon evinced by a periodic structurally chiral material—for example, a chiral sculptured thin film (STF) or a chiral liquid crystal—with a central 90°-twist defect illuminated with normally incident, circularly polarized light. Based on the coupled-wave theory (CWT), an approximate but closed-form solution of the relevant boundary-value problem is obtained in terms of a 4 × 4 CWT transmission matrix. The CWT transmission matrix is decomposed into two terms. The first term favours total transmission in the central part of the Bragg regime of the axially excited, structurally chiral material, while the second term favours total reflection in the whole Bragg regime. When the thickness of the structurally chiral material is relatively small, the second term is dominated by the first, which gives rise to a co-handed transmittance peak in the centre of the Bragg regime. As the thickness increases, the second term becomes significant and interferes with the first term such that the transmission matrix is isomorphic to that of a defect-free structurally chiral material—except in a tiny wavelength-regime wherein the
L
∞
-norms of the two terms become identical to engender the total-reflection feature. Hence, the co-handed transmittance peak diminishes (and eventually vanishes) as the thickness increases and is replaced by a cross-handed reflectance peak. The bandwidths of the two peaks depend, in different ways, on the local birefringence of the structurally chiral material.
The existence and uniqueness of bound-state solutions of a semi-linear equation
Authors: Troy W.C
Published: August 2005

We investigate the existence and uniqueness of bounded, radially symmetric solutions inR3of Δu+f(u)=0, wheref(u) is continuous, piecewise linear, and has three distinct real zeros. We give a detailed construction of the first two bound states which satisfyasr→∞. The first is the well known positive bound-state solution. The second solution changes sign and has exactly one zero in (0,∞). We prove that both of these solutions are unique.
Decay bounds in a model for aggregation of microglia: application to Alzheimer's disease senile plaques
Authors: Quinlan R.A , Straughan B
Published: August 2005

We present a model for chemotaxis, as applied to the aggregation of microglia in Alzheimer's disease. Using biological parameters found in the literature, testable thresholds are derived such that amyloid plaques are predicted not to form if conditions fall below a threshold. The model we use was developed by Luca
et al
. (Luca
et al
. 2003
Bull. Math. Biol.
65
, 693–730) and incorporates terms for both attractant and repellent signals. Our analysis can be applied to both two and three-dimensional spatial domains with application to any cell system involving chemotaxis.