bluuebunny/crossref_metadata_2025 huggingface dataset:
A contact angle measurement by laser glancing incidence method
Authors: Zhu Feng , Miao Runcai , Zhang Yani
Published: September 2008

A reflection technique to determine a contact angle by laser glancing incidence method, which is based on analyzing the reflection pattern from the up curved liquid surface (UCLS) around a smooth flat plate, is presented. In the experiment, a glass slide is vertically dipped into a tested liquid. Due to the wetting effect, the UCLS is formed around the glass slide. When an expanded and collimated laser beam impinges on the UCLS at glancing incidence, the steady and visible strip-shape dark area reflection patterns are observed. The relation of the dark region width and the maximal height of the UCLS is derived theoretically. The contact angles of distilled water and kerosene on the glass slides are calculated directly by utilizing the dark area width of the reflection patterns. Results show that an effective and practical technique for measuring the contact angle of the Wilhelmy plate is found.
Colloidal charge reversal: Dependence on the ionic size and the electrolyte concentration
Authors: Diehl Alexandre , Levin Yan
Published: September 2008

Extensive Monte Carlo simulations and scaling arguments are used to study the colloidal charge reversal. The critical colloidal surface charge density σc at which the reversal first appears is found to depend strongly on the ionic size. We find that σc has an inflection point as a function of the electrolyte concentration. The width of the plateau region in the vicinity of the inflection point depends on the temperature and the ionic radius a. In agreement with the theoretical predictions it is found that the critical colloidal charge above which the electrophoretic mobility becomes reversed diverges as Zc∼1/a2 in the limit a→0.
“Phantom ion effect” and the contact potential of the water-vapor interface
Authors: Levin Yan
Published: September 2008

The contact (junction) potential between water-vapor and water-oil interfaces is studied theoretically. Unlike the previous studies, we show that ionic contribution to the contact potential vanishes when the concentration of aqueous electrolyte goes to zero. The incorrect prediction of a large ionic contribution to the junction potential in the infinite dilution limit, obtained in the earlier studies, is traced back to the inappropriate use of the grand-canonical ensemble for strongly inhomogeneous Coulomb systems. It is shown that for these systems, the thermodynamic limit is not reached even when the number of particles is astronomically large, on the order of 1024. There is, therefore, no equivalence between statistical ensembles. For realistic, finite size systems, canonical calculation predicts a vanishing ionic contribution to the junction potentials of water-vapor and water-oil interfaces even for very concentrated electrolyte solutions.
Chaotic motions of a forced droplet-droplet oscillator
Authors: Slater D. M. , López C. A. , Hirsa A. H. , Steen P. H.
Published: September 2008

A model for the motion of two coupled spherical-cap droplets subject to periodic forcing is studied. The inviscid unforced model is a conservative second-order system, similar to Duffing’s equation. Surface tension resists the inertia of deformations from the spherical shape. Steady states of the system are parametrized by the total combined volume of the two droplet caps. The family of equilibria exhibits a classical pitchfork bifurcation, where a single lenslike symmetric steady state bifurcates into two dropletlike asymmetric states. The existence of homoclinic orbits in the unforced system suggests the possibility of chaotic dynamics in a forced, damped system. The forced damped extension is investigated for chaotic dynamics using Melnikov’s method and by calculating Lyapunov exponents. Observations are compared qualitatively to experimental results, confirming the existence of chaotic motions.
Electromagnetic turbulence driven by the mixed mode instability
Authors: Frederiksen Jacob Trier , Dieckmann Mark Eric
Published: September 2008

In continuation of a previous work, numerical results are presented, concerning relativistically counterstreaming plasmas. Here, the relativistic mixed mode instability evolves through and beyond the linear saturation, well into the nonlinear regime. Besides confirming earlier findings that wave power initially peaks on the mixed mode branch, it is observed that during late time evolution, wave power is transferred to other wave numbers. It is argued that the isotropization of power in wavenumber space may be a consequence of weak turbulence. Further, some modifications to the ideal weak turbulence limit is observed. Development of almost isotropic predominantly electrostatic—partially electromagnetic—turbulent spectra holds relevance when considering the spectral emission signatures of the plasma, namely, bremsstrahlung—partially magnetobremsstrahlung (synchrotron radiation and jitter radiation)—from relativistic shocks in astrophysical jets and from shocks in gamma-ray bursts and active galactic nuclei.
Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation
Authors: Majumder A. , Dikshit B. , Bhatia M. S. , Mago V. K.
Published: September 2008

State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data.
Design and implementation of a 120 GHz tracking interferometer with near diffraction limited focal spot
Authors: Devarapalli N. R. , Lynn A. G. , Gilmore M. , Savage M. E.
Published: September 2008

The design and implementation of a 120 GHz monostatic tracking interferometer with near diffraction limited focal spot size, used to measure line-averaged plasma density in the source of a plasma opening switch (POS), is described. Physical dimensions of the switch source place an upper limit on the focal spot size. Focusing quasioptics utilize a standard pyramidal horn and a pair of cylindrical lenses that are easily fabricated. The combination of the two cylindrical lenses transforms the asymmetric and approximately Gaussian beam produced by the pyramidal horn into a small focal spot. The circuit utilizes a tracking receiver configuration to track oscillator frequency drifts, which allow for full heterodyne quadrature operation, while avoiding the added complexity of phase or frequency locking of the sources. In order to reduce system noise in the POS pulsed power environment, all sources and amplifiers are battery powered and other noise-reducing techniques are employed. Finally, an improved Gaussian optics design methodology, which tracks the phase center of the Gaussian beam, is proposed. While not critical to this application, this method may yield improvements in systems with short focal lengths.
Growth of nonpolar (112¯) ZnO films on LaAlO3 (001) substrates
Authors: Ho Yen-Teng , Wang Wei-Lin , Peng Chun-Yen , Liang Mei-Hui , Tian Jr-Sheng , Lin Chih-Wei , Chang Li
Published: September 2008

Nonpolar (112¯0) ZnO films were grown on LaAlO3 (001) single crystal substrates at temperature from 300 to 750 °C by pulsed laser deposition method. The films were examined using x-ray diffraction, reflection high energy electron diffraction, and photoluminescence measurements for the crystallinity. The surface morphology of ZnO films from atomic force microscopy exhibits L-shaped domains. Cross-sectional transmission electron microscopy with selected area diffraction reveals two types of a-plane ZnO domains perpendicular to each other with in-plane orientation relationships of [0001]ZnO∥[11¯0]LAO and [11¯00]ZnO∥[11¯0]LAO.
Transient reverse current phenomenon in a p-n heterojunction comprised of poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) and ZnO nanowall
Authors: Maeng Jongsun , Jo Minseok , Kang Seok-Ju , Kwon Min-Ki , Jo Gunho , Kim Tae-Wook , Seo Jaeduck , Hwang Hyunsang , Kim Dong-Yu , Park Seong-Ju , Lee Takhee
Published: September 2008

We report the characteristics of a p-n heterojunction diode comprised of a poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) as the hole-conducting p-type polymer and n-type ZnO nanowall networks. ZnO nanowall networks were synthesized on a GaN/sapphire substrate without metal catalyst using hot-wall type metal organic chemical vapor deposition. The p-n heterojunction diodes of PEDOT:PSS/ZnO nanowall exhibited a space charge limited current phenomena at forward bias and a transient reverse current recovery when a sudden reverse bias was applied from the forward bias condition. The minority carrier lifetime was estimated to be ∼2.5 μs.
Electron tunneling in a strained n-type Si1−xGex/Si/Si1−xGex double-barrier structure
Authors: Hung K. M. , Cheng T. H. , Huang W. P. , Wang K. Y. , Cheng H. H. , Sun G. , Soref R. A.
Published: September 2008

We report electrical measurements on an n-type Si1−xGex/Si/Si1−xGex double-barrier structure grown on a partially relaxed Si1−yGey buffer layer. Resonance tunneling of Δ4 band electrons is demonstrated. This is attributed to the strain splitting in the SiGe buffer layer where the Δ4 band is lowest in energy at the electrode. Since the Δ4 band electrons have a much lighter effective mass along the direction of tunneling current in comparison with that of the Δ2 band electrons, this work presents an advantage over those SiGe resonant-tunneling diodes in which tunneling of Δ2 band electrons is employed.
Ultraviolet generation in periodically poled lithium tantalate waveguides
Authors: Busacca A. C. , D’Asaro E. , Pasquazi A. , Stivala S. , Assanto G.
Published: September 2008

We demonstrate ultraviolet generation in lithium tantalate channel waveguides for frequency doubling via quasi-phase-matching. The samples, proton exchanged and nanostructured by electric-field assisted surface periodic poling with domains as deep as 40μm, yield continuous wave light at 365.4nm with conversion efficiencies larger than 7.5%W−1cm−2.
Directed evolution of a G protein-coupled receptor for expression, stability, and binding selectivity
Authors: Sarkar Casim A. , Dodevski Igor , Kenig Manca , Dudli Stefan , Mohr Anja , Hermans Emmanuel , Plückthun Andreas
Published: September 2008

We outline a powerful method for the directed evolution of integral membrane proteins in the inner membrane of
Escherichia coli
. For a mammalian G protein-coupled receptor, we arrived at a sequence with an order-of-magnitude increase in functional expression that still retains the biochemical properties of wild type. This mutant also shows enhanced heterologous expression in eukaryotes (12-fold in
Pichia pastoris
and 3-fold in HEK293T cells) and greater stability when solubilized and purified, indicating that the biophysical properties of the protein had been under the pressure of selection. These improvements arise from multiple small contributions, which would be difficult to assemble by rational design. In a second screen, we rapidly pinpointed a single amino acid substitution in wild type that abolishes antagonist binding while retaining agonist-binding affinity. These approaches may alleviate existing bottlenecks in structural studies of these targets by providing sufficient quantities of stable variants in defined conformational states.
A channel connecting the mother cell and forespore during bacterial endospore formation
Authors: Meisner Jeffrey , Wang Xin , Serrano Monica , Henriques Adriano O. , Moran Charles P.
Published: September 2008

At an early stage during
Bacillus subtilis
endospore development the bacterium divides asymmetrically to produce two daughter cells. The smaller cell (forespore) differentiates into the endospore, while the larger cell (mother cell) becomes a terminally differentiated cell that nurtures the developing forespore. During development the mother cell engulfs the forespore to produce a protoplast, surrounded by two bilayer membranes, which separate it from the cytoplasm of the mother cell. The activation of σ
G
, which drives late gene expression in the forespore, follows forespore engulfment and requires expression of the
spoIIIA
locus in the mother cell. One of the
spoIIIA
-encoded proteins SpoIIIAH is targeted specifically to the membrane surrounding the forespore, through an interaction of its C-terminal extracellular domain with the C-terminal extracellular domain of the forespore membrane protein SpoIIQ. We identified a homologous relationship between the C-terminal domain of SpoIIIAH and the YscJ/FliF protein family, members of which form multimeric rings involved in type III secretion systems and flagella. If SpoIIIAH forms a similar ring structure, it may also form a channel between the mother cell and forespore membranes. To test this hypothesis we developed a compartmentalized biotinylation assay, which we used to show that the C-terminal extracellular domain of SpoIIIAH is accessible to enzymatic modification from the forespore cytoplasm. These and other results lead us to suggest that SpoIIIAH forms part of a channel between the forespore and mother cell that is required for the activation of σ
G
.
Mitochondrial complex I inhibition is not required for dopaminergic neuron death induced by rotenone, MPP
+
, or paraquat
Authors: Choi Won-Seok , Kruse Shane E. , Palmiter Richard D. , Xia Zhengui
Published: September 2008

Inhibition of mitochondrial complex I is one of the leading hypotheses for dopaminergic neuron death associated with Parkinson's disease (PD). To test this hypothesis genetically, we used a mouse strain lacking functional
Ndufs4
, a gene encoding a subunit required for complete assembly and function of complex I. Deletion of the
Ndufs4
gene abolished complex I activity in midbrain mesencephalic neurons cultured from embryonic day (E) 14 mice, but did not affect the survival of dopaminergic neurons in culture. Although dopaminergic neurons were more sensitive than other neurons in these cultures to cell death induced by rotenone, MPP
+
, or paraquat treatments, the absence of complex I activity did not protect the dopaminergic neurons, as would be expected if these compounds act by inhibiting complex 1. In fact, the dopaminergic neurons were more sensitive to rotenone. These data suggest that dopaminergic neuron death induced by treatment with rotenone, MPP
+
, or paraquat is independent of complex I inhibition.
Superoxide anions regulate TORC1 and its ability to bind Fpr1:rapamycin complex
Authors: Neklesa Taavi K. , Davis Ronald W.
Published: September 2008

The small natural product rapamycin, when bound to FKBP12, is a potent inhibitor of an evolutionarily conserved Target of Rapamycin Complex 1 (TORC1), which plays a central role in mediating cellular response to nutrient availability. Given the prominent role of TORC1 in cell growth and proliferation, clinical trials have explored the possibility of using rapamycin as an anticancer agent. Unfortunately, the percentage of patients responding favorably has been low, intensifying the need to find biomarkers able to predict rapamycin sensitivity or resistance. In this study, we elucidate the molecular mechanism underlying partial rapamycin resistance in yeast. Using the yeast deletion collection, we identified 15 deletion strains leading to partial rapamycin resistance. Among these were Cu/Zn-superoxide dismutase Sod1, copper transporter Ctr1, and copper chaperone Lys7, suggesting a role for oxidative stress in rapamycin resistance. Further analysis revealed that all 15 strains exhibit elevated levels of superoxide anions, and we show that elevated levels of reactive oxygen species specifically modify TORC1 such that it is no longer able to fully bind FKBP12:rapamycin. Therefore, elevated oxidative stress modifies TORC1 and prevents its binding to the FKBP12:rapamycin complex, ultimately leading to rapamycin resistance. These results warrant an examination into whether similar reasons explain rapamycin resistance observed in various clinical samples.
Choosing a spelling system for Mauritian Creole
Authors: Rajah-Carrim Aaliya
Published: September 2008

Mauritian Creole (Kreol) is a French-lexified creole spoken on post-colonial and multilingual Mauritius. Although it is extensively used, it has not been officially standardised. The choice of a given orthography reflects language beliefs and is therefore ideologically loaded. More specifically, the way creoles are standardised can reflect the bias towards these languages which are seen as inferior to, and dependent on, their lexifiers. In the Mauritian case, this issue is especially significant because there are now efforts to devise an official standard for the language. In 2004, the Government set up a committee to develop a standard orthography for MC. This paper considers use of, and attitudes to, written Kreol. The material presented is based on interviews conducted in Mauritius and participant observation. Although interviewees do not make extensive use of Kreol in written interactions, they tend to support the promotion of literacy in the language. Responses highlight the tension between Kreol and the colonial languages — English and French — and also the role of Kreol as an index of national identity. Our findings confirm that the choice of an orthographic system reflects linguistic and social hierarchies. I conclude that this study has practical social implications for the standardisation of Kreol.
‘That’s a Rubbaboo’
Authors: Mishler Craig
Published: September 2008

A contact language called Broken Slavey or Slavey Jargon flourished among the Gwich’in in the nineteenth century. Slavey Jargon absorbed elements of at least five source languages: French, Gwich’in, South Slavey (Dene-Tha’), Chipewyan, and English. Analyzing historical sources and recorded ethnographic texts from fluent speakers of Gwich’in, I offer an explanation of how the lexicon and grammar of this kaleidoscopic language converged regionally in the small subarctic communities of Fort McPherson, La Pierre’s House, and Fort Yukon. I also conclude that there is no internal textual evidence that Slavey Jargon was used as a trading pidgin. The polyglot form of most Slavey Jargon texts represents a curious inseam of linguistic democracy, suggesting that a measure of social equality was negotiated between the speakers of its diverse component tongues.
Comparative constructions
Authors: Dixon R.M.W.
Published: September 2008

A typology of comparative constructions is presented, with major attention to the prototypical scheme in which two participants are compared in terms of the degree of some gradable property associated with them (as in John is more handsome than Felix). In a mono-clausal comparative construction, the Parameter (which is modified by the Index of comparison) may be copula complement, head of an intransitive predicate, or a verb within a serial verb construction. There are also bi-clausal comparative constructions, and — for languages with no comparative construction per se — comparative strategies. A non-prototypical scheme involves the comparison of two properties in relation to one participant (as in John is more loyal than intelligent). There is also brief discussion of directions of origin, diffusion and spread, and non-linguistic correlations.
Rheme before theme in the noun phrase
Authors: Viti Carlotta
Published: September 2008

Information structure in the noun phrase remains unexplored or limited to the study of the s-form and the of-form in English, which are interpreted from the perspective of the Prague School. Accordingly, the prenominal s-form is chosen if the possessor expresses old information; conversely, if the possessor expresses new information, the postnominal of-form is preferred. Ancient Greek, however, indicates that this is not the sole pattern attested. In our data, drawn from Herodotus, a postposed genitive refers to the topic of the immediately preceding clauses, and has no semantically compatible referent around it. Preposed genitives denote new or discontinuous participants, and are used in contrastive and emphatic contexts. In this case, the principle “rheme before theme” can be identified.
Databases, data tombs and dust in the wind
Authors: Wren Jonathan D. , Bateman Alex
Published: September 2008

Contact:  jdwren@gmail.com

As biomedical data accumulates, the need to store, share and organize it grows. Consequently, the number of Internet-accessible databases has been rapidly growing on an annual basis. Bioinformatics regularly publishes descriptions of biomedically relevant databases, Nucleic Acids Research has published an annual database issue since 1996 and now a new open-access journal, Database: The Journal of Biological Databases and Curation, will soon be launched by Oxford University Press in 2009 (http://www.oxfordjournals.org/our_journals/databa/). Since databases can be made publicly available on the Internet without publication, it is worth considering what factors prioritize publication of database descriptions in a peer-reviewed journal. In general, publication of a database description in a journal advertises it as a valuable resource for scientific research. Implicitly, it is assumed that this resource is publicly available (most likely for free) and will be maintained. However, therein lies the problem: Database papers are simply not of the same nature as regular research articles. Over time, some databases simply become inaccessible, some are created but not maintained or updated, and some databases are never used (Galperin, 2006). Thus, for database creators, reviewers and journal editors, there are several additional considerations to judge, prior to publication, how potentially valuable these new databases may be.
Integrating and annotating the interactome using the MiMI plugin for cytoscape
Authors: Gao Jing , Ade Alex S. , Tarcea V. Glenn , Weymouth Terry E. , Mirel Barbara R. , Jagadish H.V. , States David J.
Published: September 2008

Summary: The MiMI molecular interaction repository integrates data from multiple sources, resolves interactions to standard gene names and symbols, links to annotation data from GO, MeSH and PubMed and normalizes the descriptions of interaction type. Here, we describe a Cytoscape plugin that retrieves interaction and annotation data from MiMI and links out to multiple data sources and tools. Community annotation of the interactome is supported.

Availability: MiMI plugin v3.0.1 can be installed from within Cytoscape 2.6 using the Cytoscape plugin manager in ‘Network and Attribute I/0’ category. The plugin is also preloaded when Cytoscape is launched using Java WebStart at http://mimi.ncibi.org by querying a gene and clicking ‘View in MiMI Plugin for Cytoscape’ link.

Contact:  dstates@umich.edu
Screen detection and the WHO STEPwise approach to the prevalence and risk factors of arterial hypertension in Kinshasa
Authors: Longo-Mbenza Benjamin , Ngoma Dieudonné Vangu , Nahimana Damien , Mayuku Dominique Mupepe , Fuele Simon Mbungu , Ekwanzala Florent , Beya Christian
Published: September 2008

Background

The trend of hypertension and other risk factors of cardiovascular disease is changing because of epidemiological, demographic and nutritional transitions in sub-Saharan Africa.

Objectives

The aim of this study is to determine the prevalence and risk factors of arterial hypertension in the Kinshasa region, Democratic Republic of Congo (DRC).

Design and methods

Data were collected from random sample cross-sectional surveys of adult black Africans from Kinshasa, with the help of a structured questionnaire, physical examinations and blood samples, using the World Health Organisation (WHO) stepwise approach. Sex, age, place of residence (urban versus rural), psychosocial risk factors (socioeconomic status, stress), overweight status (BMI: 25–29.9 kg/m2), general obesity (BMI: ≥ 30 kg/m2), abdominal obesity (waist circumference: ≥ 94 cm) and diabetes mellitus were considered to be the potential risk factors for screen-detected hypertension.

Results

The weighted prevalences of hypertension, diabetes mellitus, overweight status, general obesity and abdominal obesity were 15.2, 140.2, 13.5, 4.8 and 7.5%, respectively. Blood pressure and the proportion of participants with hypertension increased with age and BMI group in the population, for both men and women. Age, rural residence, low socioeconomic status, high socioeconomic status, general obesity and abdominal obesity were the risk factors for hypertension. Women aged 55 years and above had higher levels of blood pressure and hypertension than men.

Conclusion

Absolute levels of hypertension, all types of obesity and diabetes mellitus are high risk factors in the army camps and semiurban extension cities; general obesity and abdominal obesity are the risk factors for detectable hypertension. Effective control of general obesity and abdominal obesity and psychosocial strategies that target both semirural and urban areas of the Kinshasa region have the potential to prevent much premature cardiovascular disease.
Community or patient preferences for cost-effectiveness of cardiac rehabilitation: does it matter?
Authors: Oldridge Neil , Furlong William , Perkins Anthony , Feeny David , Torrance George W.
Published: September 2008

Background

Few healthcare economic evaluations, and none in cardiac rehabilitation, report results based on both community and patient preferences for health outcomes. We published the results of a randomized trial of cardiac rehabilitation after myocardial infarction in 1994 in which preferences were measured using both perspectives but only patient preferences were reported. This secondary analysis uses both types of preference measurements.

Methods

We collected community Quality of Well-Being (QWB) and patient Time Trade-off (TTO) preference scores from 188 patients (rehabilitation, n = 93; usual care, n = 95) on entry into the trial, at 2 months (end of the intervention) and again at 4, 8, and 12 months. Mean preference scores over the 12-month follow-up study period, estimates of quality-adjusted life years (QALYs) gained per patient, incremental cost-effectiveness ratios [costs inflated to 2006 US dollars] and probabilities of the cost-effectiveness of rehabilitation for costs per QALY up to US$100 000 are reported.

Results

Mean QWB preference scores were lower ( P < 0.01) than the corresponding mean TTO preference scores at each assessment point. The 12-month changes in mean QWB and TTO preference scores were large and positive ( P < 0.001) with rehabilitation patients gaining a mean of 0.011 (95% confidence interval, –0.030 to +0.052) more QWB-derived QALYs, and 0.040 (–0.026, 0.107) more TTO-derived QALYs, per patient than usual care patients. The incremental cost-effectiveness ratio for QWB-derived QALYs was estimated at $60270/QALY (about €50 600/QALY) and at $16580/QALY (about €13 900/QALY) with TTO-derived QALYs. With a willingness to spend $100 000/QALY, the probability of rehabilitation being cost-effective is 0.58 for QWB-derived QALYs and 0.83 for TTO-derived QALYs.

Conclusion

This secondary analysis of data from a randomized trial indicates that cardiac rehabilitation is cost-effective from a community perspective and highly cost-effective from the perspective of patients.
Prognostic value of double product reserve
Authors: Rafie Amir H. Sadrzadeh , Sungar Gannon W. , Dewey Frederick E. , Hadley David , Myers Jonathan , Froelicher Victor F.
Published: September 2008

Background

Although the prognostic power of exercise capacity has been demonstrated, the relative prognostic potential of other hemodynamic responses has not been thoroughly investigated. We aimed to assess the prognostic power of double product (DP) parameters in patients referred for standard exercise testing.

Design

A retrospective cohort study.

Methods

Analyses were performed on 1959 patients referred for exercise testing at the Palo Alto Veterans Affairs Medical Center from 1997 to 2006. After removal of female and heart failure patients, 1759 male veterans (mean age 57 ± 12 years) remained. DP was calculated by multiplying systolic blood pressure (SBP) and heart rate (HR); variables and their products were subtracted to obtain the differences between rest and maximal exercise (reserve), and recovery.

Results

Multivariate Cox survival analysis was performed for 157 all-cause and 53 cardiovascular deaths during a mean follow-up of 5.4 ± 2.1 years. Although most of the hemodynamic variables were individually significant in Cox survival analysis, when age, DP reserve, exercise capacity (in metabolic equivalents), and HR recovery were entered together, only age and DP reserve were chosen. Of all hemodynamic measurements considered, DP reserve was the strongest predictor of cardiovascular prognosis after adjustment for age (Wald Z-score,-5.12; P < 0.0001) and when considering other potential confounders such as age, β-blocker use, and the Duke treadmill Score (Wald Z-score, –3.84; P < 0.0001).

Conclusion

In this study population, DP reserve had greater prognostic power than metabolic equivalents, maximal HR or systolic blood pressure, or HR recovery.
Marital status and cardiac rehabilitation attendance: a meta-analysis
Authors: Molloy Gerard J. , Hamer Mark , Randall Gemma , Chida Yoichi
Published: September 2008

Background

Marital status has been clearly linked to subsequent health outcomes in those with established coronary heart disease (CHD). This robust association may be because of both pathophysiological and behavioural mechanisms.

Design

We employed meta-regression to examine the association between marital status and attendance at outpatient cardiac rehabilitation (CR) in published studies.

Methods

We searched electronic databases, for example, Medline and Science Citation Index, for published studies that reported an association between a measure of marital or partnered status and CR attendance in patients with diagnosed CHD.

Results

Eleven studies were identified which incorporated 6984 CHD patients. Being married/partnered was associated with significantly higher odds of attending CR. Using a fixed effects model, the pooled odds ratio of CR attendance was 1.72 [95% confidence interval (CI) 1.50–1.97] for those who were married/partnered. There was no evidence of heterogeneity of effects ( P = 0.42) or publication bias ( P = 0.12).

Conclusion

CHD patients who are married or have a partner are between 1.5–2 times more likely to attend CR. Associations between marital status and CR attendance may partly explain CHD outcomes.
Adherence to a Mediterranean-type diet and reduced prevalence of clustered cardiovascular risk factors in a cohort of 3204 high-risk patients
Authors: Sánchez-Taínta Ana , Estruch Ramón , Bulló Mónica , Corella Dolores , Gómez-Gracia Enrique , Fiol Miquel , Algorta Jaime , Covas María-Isabel , Lapetra José , Zazpe Itziar , Ruiz-Gutiérrez Valentina , Ros Emilio , Martínez-González Miguel A. ,   for the PREDIMED group
Published: September 2008

Background

The Mediterranean food pattern (MeDiet) has been suggested to have beneficial effects on cardiovascular risk factors. Scarcity of assessment of this effect on large samples of patients at high risk is, however, observed. Our objective was to estimate the association between adherence to MeDiet and the prevalence of risk factors in 3204 asymptomatic high-risk patients.

Design

Cross-sectional assessment of baseline characteristics of participants in a primary prevention trial.

Methods

Participants were assessed by their usual primary-care physicians to ascertain the prevalence of diet-related cardiovascular risk factors (diabetes, hypertension, dyslipidemia, or obesity) using standard diagnostic criteria. A dietitian interviewed each participant to obtain a 14-point score measuring the degree of adherence to MeDiet.

Results

Adherence to MeDiet was inversely associated with individual risk factors and, above all, with the clustering of them. The multivariate adjusted odds ratio to present simultaneously the four risk factors for those above the median value of the MeDiet score was 0.67 (95% confidence interval: 0.53–0.85). The multivariate odds ratios for successive categories of adherence to MeDiet were 1 (ref.), 1.03, 0.85, 0.70 and 0.54 ( P for trend ≤0.001).

Conclusion

Following a MeDiet was inversely associated with the clustering of hypertension, diabetes, obesity, and hypercholesterolemia among high-risk patients.
C-reactive protein, insulin resistance and risk of cardiovascular disease: a population-based study
Authors: Jeppesen Jørgen , Hansen Tine W. , Olsen Michael H. , Rasmussen Susanne , lbsen Hans , Torp-Pedersen Christian , Hildebrandt Per R. , Madsbad Sten
Published: September 2008

Background

C-reactive protein (CRP), a marker of inflammation, and insulin resistance (IR), a metabolic disorder, are closely related. CRP and IR have both been identified as significant risk factors of cardiovascular disease (CVD) after adjustment for conventional CVD risk factors. It is not clear whether CRP predicts CVD independent of IR.

Design

Prospective population-based study.

Methods

Two thousand three hundred and fifty-seven Danish men and women, recruited from the general population, aged 41–72 years, without major CVD at baseline were studied. Traditional and new risk factors were recorded at baseline. CRP was determined by a high-sensitivity assay, and IR was determined by the homoeostasis model assessment (HOMA-IR) method.

Results

Over a median follow-up of 9.4 years, the incidence of the prespecified CV event, defined as the composite event of CV death, nonfatal ischaemic heart disease and nonfatal stroke, amounted to 222 cases. In Cox proportional-hazard models, adjusted for age, sex, smoking habit, total cholesterol, waist circumference, levels of triglycerides and high-density lipoprotein-cholesterol, systolic and diastolic blood pressures, physical activity and HOMA-IR, the hazard ratio (95% confidence interval) of a CV event was 1.33 (1.14–1.55; 0.001) per standard deviation increase in log-transformed CRP level. In the same model, the hazard ratio of a CV event was 1.11 (1.02–1.21; P < 0.05) per standard deviation increase in HOMA-IR level.

Conclusion

In a general Danish population free of major CVD at baseline, both CRP and IR were significantly related to risk of CVD.
Circulating progenitor cells decrease immediately after marathon race in advanced-age marathon runners
Authors: Adams Volker , Linke Axel , Breuckmann Frank , Leineweber Kirsten , Erbs Sandra , Kränkel Nicolle , Bröcker-Preuss Martina , Woitek Felix , Erbel Raimun d , Heusch Gerd , Hambrecht Rai ner , Schuler Gerhard , Möhlenkamp Stefan
Published: September 2008

Introduction

Exercise is thought to stimulate the release of hematopoietic and endothelial progenitor cells (EPC) from the bone marrow. Little is known about the influence of strenuous exercise on the content of circulating progenitor cells. The aim of this study was to investigate the influence of a marathon race on the amount of circulating progenitor cells immediately after the race in advanced-aged runners.

Methods

Sixty-eight healthy marathon runners (age: 57 ± 6 years) were included in this study. Blood cell counts were evaluated by standard methods, and circulating progenitor cells before and immediately after the race were quantified by fluorescence-activated cell sorter (FACS). Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) was quantified by enzyme-linked immunosorbent assay.

Results

A marathon race led to a significant increase in white blood cell count (5283 ± 155 vs. 13706 ± 373 cells/μl; P < 0.001). Fluorescence-activated cell sorter analysis revealed a significant decrease of CD34pos cells (1829 ± 115 vs. 1175 ± 75 cells/ml blood; P < 0.0001), CD117pos cells (2478 ± 245 vs. 2193 ± 85 cells/ml blood; P < 0.05), and CD133pos cells (3505 ± 286 vs. 2239 ± 163 cells/ml blood; P < 0.001). No significant change was observed for EPCs defined as CD34pos/VEGF-R2pos cells (117 ± 8 vs. 128 ± 9cells/ml blood; P = 0.33). With respect to VEGF a significant downregulation was evident directly after the race (48.9 ± 8.0 vs. 34.0 ± 7.5 pg/ml; P < 0.05), whereas no change was obvious in EGF levels.

Conclusion

The results of our study suggest that finishing a marathon race will lead to an inflammatory response and downregulation of circulating hematopoietic stem cells. With respect to EPCs no change is observed, which may be because of a greater differentiation of the remaining CD34pos cells towards EPCs.
Dependence of Hearing Changes on the Dose of Intratympanically Applied Gentamicin: A Meta‐Analysis Using Mathematical Simulations of Clinical Drug Delivery Protocols
Authors: Salt Alec N. , Gill Ruth M. , Plontke Stefan K.
Published: September 2008

Objectives/Hypothesis: To establish safe dosing protocols for the treatment of patients with Meniere's disease with intratympanic gentamicin.

Study Design: A validated computer model of gentamicin dispersion in the inner ear fluids was used to calculate cochlear drug levels resulting from specific clinical delivery protocols. Dosing in the cochlea was compared with changes of hearing sensitivity for 568 patients reported in 19 publications.

Methods: Cochlear drug levels were calculated based on the concentration and volume of gentamicin applied, the time the drug remained in the middle ear, and on the specific timing of injections. Time courses were quantified in terms of the maximum concentration (C
max) and the area under the curve of the drug at specific cochlear locations.

Results: Drug levels resulting from single, “one‐shot” injections were typically lower than those from repeated or continuous application protocols. Comparison of hearing sensitivity changes with gentamicin dosing revealed a flat curve with a near‐zero mean for lower doses, suggesting that hearing changes with doses over this range were probably unrelated to the applied drug. Higher intracochlear doses were generated with repeated or continuous delivery protocols, which in some cases caused substantial hearing losses and an increased incidence of deafened ears.

Conclusions: One‐shot application protocols produce gentamicin doses in the cochlea that have minimal risk to hearing at the frequencies tested. Repeated or continuous application protocols result in higher doses that in some cases damage hearing. The high variability of hearing changes, even with low gentamicin doses, calls into question the rationale for using individual hearing changes to titrate the applied dose.
The Use of the Pulse Dye Laser in the Treatment of Vocal Fold Scar: A Preliminary Study
Authors: Mortensen Melissa M. , Woo Peak , Ivey Chandra , Thompson Chandler , Carroll Linda , Altman Kenneth
Published: September 2008

Objectives/Hypothesis: Dysphonia due to vocal fold scarring is a challenging problem to the laryngologist. Vocal fold scarring after radiation, phonosurgery, and laser cordectomy causes moderate to severe dysphonia. Surgical attempts at scar removal and voice restoration have limited success. Pulsed dye laser (PDL) treatment has been shown to be effective in softening scarred skin by serial office treatments. The objective of this preliminary study was to evaluate the use of the PDL in the management of patients with established vocal fold scar.

Study Design: This is an Institutional Review Board‐approved prospective study involving 11 patients. The causes of scarring were phonosurgery (n = 7), radiation (n = 2), and partial laryngectomy (n = 2). The subjects were evaluated pre‐ and postprocedure using the voice handicap index (VHI), laryngeal stroboscopy rating, voice recordings with acoustic and aerodynamic analysis, and self‐evaluation.

Methods: The PDL was applied with the fiberoptic delivery system by three treatments at 1‐month intervals in the office setting. Each treatment endpoint was blanching of the treatment site.

Results: There were three women and eight men in our study group. Ten of 11 patients subjectively improved by self‐rating. No patients were worse. VHI improved from 48.44 pretreatment to 35.55 at 6 months posttreatment (P < .05). The jitter at 6 months improved from 2.230% to 1.654% (P = NS) and shimmer improved from 3.679% to 3.196% (P = NS). The noise to harmonic ration improved from 0.1428 to 0.1316 (P = NS). The mean phonotory flow went from 0.177 to 0.254 L/S (P < .05).Three raters blinded to treatment sequence rated the posttreatment stroboscopy findings as better than pretreatment in a forced choice comparison, kappa score 0.903.

Conclusion: PDL is a safe and potentially promising treatment for established vocal fold scar. Subjectively, no patients were worse and 10 of 11 patients reported improved voice. There was improvement in the VHI, acoustic measures of shimmer and jitter, and stroboscopy findings. Further study using this approach in a larger cohort seems to be warranted.
Radiofrequency Ablation for the Treatment of Obstructive Sleep Apnea: A Meta‐analysis
Authors: Farrar Joshua , Ryan James , Oliver Eric , Gillespie M Boyd
Published: September 2008

Objectives/Hypothesis: Recent studies suggest that radiofrequency ablation (RFA) is a treatment option for patients with obstructive sleep apnea (OSA). This study investigates the effectiveness of RFA in treating OSA using a critical literature review and meta‐analysis.

Study Design: Critical literature review and meta‐analysis.

Methods: Two independent searches of PubMed 1966‐present were performed to identify publications pertaining to RFA and OSA. Effectiveness of the procedure was measured by comparing the Epworth Sleepiness Scale (ESS), respiratory disturbance index (RDI), and lowest O2 saturation before and after tissue ablation.

Results: Sixteen studies met the inclusion criteria. The study found a 31% reduction in short‐term ESS (odds ratios (OR) 0.69, 95% confidence interval (CI) 0.63–0.75), which was maintained beyond 12 months (OR 0.68, 95% CI 0.43–0.73). Likewise, RFA resulted in a 31% reduction in short term (<12 month) (OR 0.69, 95% CI 0.61–0.77) and 45% reduction (OR 0.55, 95% C.I. 0.45–0.72) in long‐term (>24 month) RDI levels. Short‐term results of the lowest O2 saturations failed to demonstrate improvement (OR 1.03, 95% CI 0.88–1.20).

Conclusion: RFA seems to be a clinically effective tool that reduces ESS scores and RDI levels in patients with OSA syndrome. The procedure should be considered a valid treatment option for patients who refuse or are unable to tolerate continuous positive airway pressure.
Cricothyroidotomy vs. Sternal Tracheotomy for Challenging Airway Anatomy
Authors: Patel Krishna G. , Zdanski Carlton J.
Published: September 2008

Although tracheotomies are the standard procedure for elective surgical airways, some patients present with challenging anatomy. In circumstances of abnormal skeletal deformities, such as kyphoscoliosis, the airway is also often tortuous and access to the trachea may be difficult. In the situation of severely distorted tracheal anatomy, where access to the trachea may require a mediansternotomy, a cricothyroidotomy may be the safer option. This article details the technique involved in approaching a substernal larynx and stomatizing a cricothyroidotomy for a patient who required a long‐term surgical airway secondary to severe kyphoscoliosis from Proteus syndrome and failure to extubate.
Esophageal Reconstruction With Larynx Preservation Using Forearm‐Free Flap
Authors: Agrawal Amit , Husein Omar F. , Schuller David E.
Published: September 2008

Surgery for cervical esophageal malignancy frequently involves comcomitant total laryngectomy carried out because of either oncologic or functional concerns. Though uncommon, preservation of the larynx has, in recent years, been described in patients undergoing cervical esophagectomy with reconstruction of the resulting circumferential esophageal defect achieved using either free jejunal flaps or gastric pullup procedures. The use of tubed‐free cutaneous flaps for circumferential cervical esophageal reconstruction, however, has been rarely described in situations where the larynx has been preserved. We describe successful use of a tubed radial forearm‐free flap for reconstruction of a circumferential cervical esophageal defect with preservation of the larynx. Use of the radial forearm flap in this situation resulted in minimal donor site‐related morbidity, avoided the need for laparotomy and excellent voice and swallowing function were maintained. As such, use of tubed cutaneous free flaps can be considered an option for cervical esophageal reconstruction when the larynx has been preserved
Assessment of Operative Competency in Otolaryngology Residency: Survey of US Program Directors
Authors: Brown David J. , Thompson Richard E. , Bhatti Nasir I.
Published: September 2008

Objectives/Hypothesis: 1) Assess current status of operative competency assessment and feedback among US Otolaryngology residency programs. 2) Evaluate correlations between assessment or feedback tools and remediation.

Study Design: Survey of Program Directors.

Methods: The survey was sent to 100 Program Directors inquiring about program size, mode of feedback, assessment tools, surgical portfolios, remediation, and number of residents requiring remediation in past 5 years. Associations between assessment questions and remediation (yes or no) were statistically assessed with the χ2 goodness‐of‐fit test. For more complicated analyses, multiple logistic regression models were created to assess predictors of the binary outcome of radiation.

Results: Among 72 respondents, subjective evaluations are used by 95.8% (69 of 72). Formative feedback after cases is used by 38.9% (28 of 72). Summative feedback at end of the rotation is done by 57.0% (41 of 72). Objective Structured Assessments of Technical Skills is used by 15.3% (11 of 72) of programs, most are large on the basis of number of residents or faculty or both. Operative portfolios are kept by 48.6% (35 of 72) of programs. The percentage of programs with mechanisms for remediation is 41.7% (30 of 72). Similarly, of the programs who responded to the remediation question, the percentage with at least one resident requiring remediation is 37.5%. Programs who report at least one resident remediation are statistically more likely to have a remediation mechanism in place (75% vs. 27.5%; P <.001). There is also a statistically significant association with formative feedback and having resident remediation (58.3% vs. 30%; P = .025).

Conclusions: Standardized surgical curricula and assessment tools are needed. Programs with more intensive evaluation or remediation mechanisms are statistically more likely to report residents requiring remediation. This may reflect their ability to better identify the struggling resident. Alternatively, having a resident requiring remediation may be the catalyst that initiates the need for more intensive evaluation tools and remediation mechanisms. The Accreditation Council for Graduate Medical Education's and society will demand that we produce competent surgeons. Therefore, all Otolaryngology training programs should be developing and implementing formal surgical assessment tools, methods to identify residents requiring remediation, and remediation mechanisms.