bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, characterisation and catalase‐like activity of silica‐coated magnetite nanoparticles modified by a Schiff base Mn complex
Authors: Tian Le , Lou Xia , Pan Zhi Quan , Huang Qi Mao , Zhou Hong
Published: May 2013

Silica‐coated magnetite nanoparticles (Mn‐L1‐NPs), modified by a Mn complex of N, N′‐bis(3‐formyl‐5‐methylsalicylidene)ethylenediimine (L1), have been synthesised and characterised by Fourier transform infrared spectroscopy, scanning electron microscope, X‐ray photoelectron spectroscopy, atomic absorption spectroscopy and thermogravimetric analysis techniques. The catalase‐like activity of Mn‐L1‐NPs was evaluated by its ability to catalytically decompose hydrogen peroxide in aqueous solution. The results indicated that the nanoparticles have higher catalase‐like activity.
Morphological, structural and optical properties of Al‐doped ZnO nanosheet arrays influenced by pulsed electromagnetic field
Authors: Wang Jianzhong , Tang Li‐dan , Wang Bing , Du Huiling , Qi Jingang , Peng Shujing
Published: May 2013

High‐quality Al‐doped ZnO nanosheet arrays have been prepared by hydrothermal methods assisted with the pulsed electromagnetic field (PEMF). These effects of PEMF on the morphology and structural properties of Al‐doped ZnO nanosheet arrays were studied in detail. Results showed Al‐doped ZnO nanosheet arrays with PEMF had better orientation, more density, a greater ratio of diameter to thickness and stronger ultraviolet emission peak than those without PEMF. Finally, a possible mechanism of PEMF acting on Al‐doped ZnO nanosheet arrays is proposed.
Lift‐off process of piezoelectric lead–zirconate–titanate thin film using self‐assembled monolayer as sacrificial layer
Authors: Lu Jian , Takagi Hideki , Maeda Ryutaro
Published: May 2013

In this work, a hydrophobic self‐assembled monolayer, perfluorodecyltrichlorosilane (FDTS) (CF3(CF2)7 (CH2)2SiCl3), was proposed as a sacrificial layer for a lift‐off process of a piezoelectric lead–zirconate–titanate (PZT) thin film on a Pt/Ti/SiO2/Si substrate. A FDTS fine pattern was firstly vapour deposited on a Pt/Ti/SiO2/Si substrate by a lift‐off process, and then the PZT precursor was spin‐coated on the Pt/Ti/SiO2/Si substrate, post‐baked so the solvent decomposed and evaporated and annealed for crystallisation. The experimental results demonstrated that the super‐hydrophobic FDTS with a contact angle of >120° is effective in preventing PZT crystallisation because of its thermal stability during PZT post‐baking, and its barrier‐effects between the spin‐coated PZT precursor and the Pt/Ti substrate. After removing the FDTS and the PZT which is on top of the FDTS by a second lift‐off process using ultrasonic agitation, a PZT fine pattern was successfully obtained on the Pt/Ti/SiO2/Si substrate with a thickness of 200–300 nm and feature size of a few tens of microns. In this Letter, the hydrophobic properties and surface morphology of different types of FDTS were studied and its barrier‐effect on PZT crystallisation were analysed. The effects of PZT thickness in each spin‐coating to lift‐off the and PZT properties were investigated. The obtained PZT pattern was evaluated by an X‐ray diffraction measurement.
Room‐temperature synthesis of Mg(OH)2 nanorods and nanowires in Mg–H2O–NaCl reaction system
Authors: Liu Zongjian , Chen Jingyun , Zheng Yifan
Published: May 2013

A novel method based on the reaction between Mg foil and water in the presence of NaCl has been employed to synthesise one‐dimensional (1D) Mg(OH)2 nanostructures. It is found that the presence of NaCl not only increases the reaction rate but also results in the formation of 1D Mg(OH)2 nanostructures with their morphologies being related to the NaCl concentration. Nanorods with 100–400 nm in width and more than 1 μm in length are observed when the NaCl concentration is low, whereas nanowires with 20–120 nm in diameter and several micrometres in length and their self‐assembled nest‐like structures are formed in the case of high NaCl concentration. The authors’ results have also shown that both nanorods and nanowires grow along the [110] direction. Based on experimental observations, a possible mechanism is proposed for the growth of 1D Mg(OH)2 nanostructures and their self‐assembled structures.
Surface modification of nanoparticles with octadecyl trichlorosilane and its effects on photocatalytic activity
Authors: Qian Jianhua , Ma Quanliang , Xu Jiasheng
Published: May 2013

The surfaces of titanium dioxide (TiO2) nanoparticles were modified with octadecyl trichlorosilane (OTS) as a coupling agent in different conditions. In order to improve the nanoparticles' dispersion and transform the interactions between nanoparticles in different conditions, the grafting of OTS on the TiO2 nanoparticles' surface was characterised by thermogravimetric analysis and Fourier transform infrared techniques. An ultraviolet (UV) spectrophotometer was employed to evaluate the absorbance of UV‐light in the wavelength range of 200–900 nm. To assess the light catalytic activity, UV/vis diffuse reflectance spectra were applied to detect the absorbance of Rhodamine B, which was absorbed in the dark and degraded under a lamp. An effective method has been provided to improve photocatalytic activity, which may also be applied to the modification of other nanomaterials.
Hohlraum energetics scaling to 520 TW on the National Ignition Facility
Authors: Kline J. L. , Callahan D. A. , Glenzer S. H. , Meezan N. B. , Moody J. D. , Hinkel D. E. , Jones O. S. , MacKinnon A. J. , Bennedetti R. , Berger R. L. , Bradley D. , Dewald E. L. , Bass I. , Bennett C. , Bowers M. , Brunton G. , Bude J. , Burkhart S. , Condor A. , Di Nicola J. M. , Di Nicola P. , Dixit S. N. , Doeppner T. , Dzenitis E. G. , Erbert G. , Folta J. , Grim G. , Glenn S. , Hamza A. , Haan S. W. , Heebner J. , Henesian M. , Hermann M. , Hicks D. G. , Hsing W. W. , Izumi N. , Jancaitis K. , Jones O. S. , Kalantar D. , Khan S. F. , Kirkwood R. , Kyrala G. A. , LaFortune K. , Landen O. L. , Lagin L. , Larson D. , Pape S. Le , Ma T. , MacPhee A. G. , Michel P. A. , Miller P. , Montincelli M. , Moore A. S. , Nikroo A. , Nostrand M. , Olson R. E. , Pak A. , Park H. S. , Patel J. P. , Pelz L. , Ralph J. , Regan S. P. , Robey H. F. , Rosen M. D. , Ross J. S. , Schneider M. B. , Shaw M. , Smalyuk V. A. , Strozzi D. J. , Suratwala T. , Suter L. J. , Tommasini R. , Town R. P. J. , Van Wonterghem B. , Wegner P. , Widmann K. , Widmayer C. , Wilkens H. , Williams E. A. , Edwards M. J. , Remington B. A. , MacGowan B. J. , Kilkenny J. D. , Lindl J. D. , Atherton L. J. , Batha S. H. , Moses E.
Published: May 2013

Indirect drive experiments have now been carried out with laser powers and energies up to 520 TW and 1.9 MJ. These experiments show that the energy coupling to the target is nearly constant at 84% ± 3% over a wide range of laser parameters from 350 to 520 TW and 1.2 to 1.9 MJ. Experiments at 520 TW with depleted uranium hohlraums achieve radiation temperatures of ∼330 ± 4 eV, enough to drive capsules 20 μm thicker than the ignition point design to velocities near the ignition goal of 370 km/s. A series of three symcap implosion experiments with nearly identical target, laser, and diagnostics configurations show the symmetry and drive are reproducible at the level of ±8.5% absolute and ±2% relative, respectively.
Influence of hydrogen on the regeneration of boron-oxygen related defects in crystalline silicon
Authors: Wilking S. , Herguth A. , Hahn G.
Published: May 2013

When exposed to light, boron doped monocrystalline Czochralski grown silicon suffers from degradation of the minority carrier lifetime due to the formation of recombination active boron-oxygen related defects. The so called regeneration procedure is able to convert these recombination active defects into a new less recombination active state characterized by a higher minority charge carrier lifetime and stability under illumination. However, the exact working principle on microscopic scale is still unknown even though some influencing factors were identified. The role of hydrogen in the regeneration process is investigated in this work. We find that the characteristic regeneration time constant is subject to variation depending on the process parameters of a Plasma Enhanced Chemical Vapor Deposition a-SiNx:H deposition, namely the applied gas flows, as well as on the thermal history of the sample prior to applying the regeneration procedure. The positive effect of a short high temperature (800–900 °C) step leads to the idea that the presence of atomic hydrogen in the silicon bulk is crucial for the regeneration effect to occur. The different regeneration behavior of samples with variable thickness of a hydrogen diffusion barrier, namely an Al2O3 layer capped by SiNx:H, supports those results. Finally, the importance of hydrogen for regeneration is directly shown on samples having different hydrogen bulk concentrations due to direct hydrogenation in a Microwave Induced Remote Hydrogen Plasma reactor. A new model to explain the effect of the regeneration of boron-oxygen related defect centers based on the possible role of atomic hydrogen is presented.
Development and application of an instrument for spatially resolved Seebeck coefficient measurements
Authors: Zakutayev Andriy , Luciano Frank J. , Bollinger Vincent P. , Sigdel Ajaya K. , Ndione Paul F. , Perkins John D. , Berry Joseph J. , Parilla Philip A. , Ginley David S.
Published: May 2013

The Seebeck coefficient is a key indicator of the majority carrier type (electrons or holes) in a material. The recent trend toward the development of combinatorial materials research methods has necessitated the development of a new high-throughput approach to measuring the Seebeck coefficient at spatially distinct points across any sample. The overall strategy of the high-throughput experiments is to quickly identify the region of interest on the sample at some expense of accuracy, and then study this region by more conventional techniques. The instrument for spatially resolved Seebeck coefficient measurements reported here relies on establishing a temperature difference across the entire compositionally graded thin-film and consecutive mapping of the resulting voltage as a function of position, which facilitates the temperature-dependent measurements up to 400 °C. The results of the designed instrument are verified at ambient temperature to be repeatable over 10 identical samples and accurate to within 10% versus conventional Seebeck coefficient measurements over the −100 to +150 μV/K range using both n-type and p-type conductive oxides as test cases. The developed instrument was used to determine the sign of electrical carriers of compositionally graded Zn–Co–O and Ni–Co–O libraries prepared by combinatorial sputtering. As a result of this study, both cobalt-based materials were determined to have p-type conduction over a broad single-phase region of chemical compositions and small variation of the Seebeck coefficient over the entire investigated range of compositions and temperature.
Viscoelasticity of blood and viscoelastic blood analogues for use in polydymethylsiloxane in vitro models of the circulatory system
Authors: Campo-Deaño Laura , Dullens Roel P. A. , Aarts Dirk G. A. L. , Pinho Fernando T. , Oliveira Mónica S. N.
Published: May 2013

The non-Newtonian properties of blood are of great importance since they are closely related with incident cardiovascular diseases. A good understanding of the hemodynamics through the main vessels of the human circulatory system is thus fundamental in the detection and especially in the treatment of these diseases. Very often such studies take place in vitro for convenience and better flow control and these generally require blood analogue solutions that not only adequately mimic the viscoelastic properties of blood but also minimize undesirable optical distortions arising from vessel curvature that could interfere in flow visualizations or particle image velocimetry measurements. In this work, we present the viscoelastic moduli of whole human blood obtained by means of passive microrheology experiments. These results and existing shear and extensional rheological data for whole human blood in the literature enabled us to develop solutions with rheological behavior analogous to real whole blood and with a refractive index suited for PDMS (polydymethylsiloxane) micro- and milli-channels. In addition, these blood analogues can be modified in order to obtain a larger range of refractive indices from 1.38 to 1.43 to match the refractive index of several materials other than PDMS.
Uncertainty quantification in MD simulations of concentration driven ionic flow through a silica nanopore. II. Uncertain potential parameters
Authors: Rizzi F. , Jones R. E. , Debusschere B. J. , Knio O. M.
Published: May 2013

This article extends the uncertainty quantification analysis introduced in Paper I for molecular dynamics (MD) simulations of concentration driven ionic flow through a silica nanopore. Attention is now focused on characterizing, for a fixed pore diameter of D = 21 Å, the sensitivity of the system to the Lennard-Jones energy parameters, \documentclass[12pt]{minimal}\begin{document}$\varepsilon _{\text{Na}^+}$\end{document}ɛNa+ and \documentclass[12pt]{minimal}\begin{document}$\varepsilon _{\text{Cl}^-}$\end{document}ɛCl−, defining the depth of the potential well for the two ions Na+ and Cl−, respectively. A forward propagation analysis is applied to map the uncertainty in these parameters to the MD predictions of the ionic fluxes. Polynomial chaos expansions and Bayesian inference are exploited to isolate the effect of the intrinsic noise, stemming from thermal fluctuations of the atoms, and properly quantify the impact of parametric uncertainty on the target MD predictions. A Bayes factor analysis is then used to determine the most suitable regression model to represent the MD noisy data. The study shows that the response surface of the Na+ conductance can be effectively inferred despite the substantial noise level, whereas the noise partially hides the underlying trend in the Cl− conductance data over the studied range. Finally, the dependence of the conductances on the uncertain potential parameters is analyzed in terms of correlations with key bulk transport coefficients, namely, viscosity and collective diffusivities, computed using Green-Kubo time correlations.
Integration of strain feedback and charge drive for high-performance of piezoelectric actuators
Authors: Zhang Jie , Zhang Liansheng , Feng Zhihua
Published: May 2013

This paper introduces a hybrid control method that combines strain feedback control and charge driver. Strain feedback control method has good stability at low frequencies but suffers from limited resolution at high frequencies. The charge driver provides good linearity at high frequencies but exhibits drift at low frequencies. This study combines these two control methods to demonstrate that high stability at low frequencies as well as good linearity and high resolution at high frequencies can be achieved. Theoretical analyses are provided in detail. Experimental results demonstrate the proposed hybrid control method can provide excellent stability, good linearity and high resolution from 0.01 Hz to 50 Hz.
Slater-Pauling behavior in LiMgPdSn-type multifunctional quaternary Heusler materials: Half-metallicity, spin-gapless and magnetic semiconductors
Authors: Özdoğan K. , Şaşıoğlu E. , Galanakis I.
Published: May 2013

We employ ab-initio electronic structure calculations to study 60 LiMgPdSn-type (also known as LiMgPdSb-type) quaternary Heusler compounds. All compounds obey the Slater-Pauling rule with diverse electronic and magnetic properties. 41 compounds are found to be half-metals, 8 spin-gapless semiconductors, and 9 semiconductors. CoVTiAl and CrVTiAl compounds are identified as ferromagnetic and antiferromagnetic semiconductors, respectively, with large energy gaps in both spin directions. All magnetic compounds are expected to have high Curie temperatures making them suitable for spintronics/magnetoelectronics applications.
Comparisons of linear and nonlinear plasma response models for non-axisymmetric perturbations
Authors: Turnbull A. D. , Ferraro N. M. , Izzo V. A. , Lazarus E. A. , Park J.-K. , Cooper W. A. , Hirshman S. P. , Lao L. L. , Lanctot M. J. , Lazerson S. , Liu Y. Q. , Reiman A. , Turco F.
Published: May 2013

With the installation of non-axisymmetric coil systems on major tokamaks for the purpose of studying the prospects of ELM-free operation, understanding the plasma response to the applied fields is a crucial issue. Application of different response models, using standard tools, to DIII-D discharges with applied non-axisymmetric fields from internal coils, is shown to yield qualitatively different results. The plasma response can be treated as an initial value problem, following the system dynamically from an initial unperturbed state, or from a nearby perturbed equilibrium approach, and using both linear and nonlinear models [A. D. Turnbull, Nucl. Fusion 52, 054016 (2012)]. Criteria are discussed under which each of the approaches can yield a valid response. In the DIII-D cases studied, these criteria show a breakdown in the linear theory despite the small 10−3 relative magnitude of the applied magnetic field perturbations in this case. For nonlinear dynamical evolution simulations to reach a saturated nonlinear steady state, appropriate damping mechanisms need to be provided for each normal mode comprising the response. Other issues arise in the technical construction of perturbed flux surfaces from a displacement and from the presence of near nullspace normal modes. For the nearby equilibrium approach, in the absence of a full 3D equilibrium reconstruction with a controlled comparison, constraints relating the 2D system profiles to the final profiles in the 3D system also need to be imposed to assure accessibility. The magnetic helicity profile has been proposed as an appropriate input to a 3D equilibrium calculation and tests of this show the anticipated qualitative behavior.
Kinetics and thermodynamics associated with Bi adsorption transitions at Cu and Ni grain boundaries
Authors: Tai Kaiping , Feng Lin , Dillon Shen J.
Published: May 2013

The grain boundary diffusivity of Au in Cu and Cu-Bi, and Cu in Ni and Ni-Bi are characterized by secondary ion mass spectroscopy depth profiling. Samples are equilibrated in a Bi containing atmosphere at temperatures above and below the onset of grain boundary adsorption transitions, sometimes called complexion transitions. A simple thermo-kinetic model is used to estimate the relative entropic contributions to the grain boundary energies. The results indicate that the entropy term plays a major role in promoting thermally and chemically induced grain boundary complexion transition.
Substrate-independent catalyst-free synthesis of high-purity Bi2Se3 nanostructures
Authors: Mlack Jerome T. , Rahman Atikur , Johns Gary L. , Livi Kenneth J. T. , Marković Nina
Published: May 2013

We describe a catalyst-free vapor-solid synthesis of bismuth selenide (Bi2Se3) nanostructures at ambient pressure with H2 as carrier gas. The nanostructures were synthesized on glass, silicon, and mica substrates and the method yields a variety of nanostructures: nanowires, nanoribbons, nanoplatelets, and nanoflakes. The materials' analysis shows high chemical purity in all cases, without sacrificing the crystalline structure of Bi2Se3. Low-temperature measurements of the nanostructures indicate contributions from the surface states with a tunable carrier density. Samples synthesized on flexible mica substrates show no significant change in resistance upon bending, indicating robustness of as-grown Bi2Se3 nanostructures and their suitability for device applications.
Effect of polarization on intersubband transition in AlGaN/GaN multiple quantum wells
Authors: Chen G. , Li Z. L. , Wang X. Q. , Huang C. C. , Rong X. , Sang L. W. , Xu F. J. , Tang N. , Qin Z. X. , Sumiya M. , Chen Y. H. , Ge W. K. , Shen B.
Published: May 2013

Intersubband transitions (ISBT) of AlGaN/GaN multiple quantum wells (MQWs) with wavelength towards atmospheric window (3–5 μm) have been investigated. A Ga-excess epitaxial method is used in the molecular beam epitaxy leading to ultra-sharp interface and negligible elements inter-diffusion. The absorption peak wavelength of the ISBT was successfully tuned in the range of 3–4 μm by modifying the GaN well thickness from 2.8 to 5.5 nm. It was further found that the polarization charge density of the AlGaN/GaN MQWs was about −0.034 C/m2 which gave rise to blueshift of the ISBT wavelength and thus partially compensated its redshift with increasing well thickness.
Visible-light photoresponse of AlN-based film bulk acoustic wave resonator
Authors: Zhou C. J. , Yang Y. , Shu Y. , Cai H. L. , Ren T. L. , Chan M. , Zhou J. , Jin H. , Dong S. R. , Yang C. Y.
Published: May 2013

Visible-light photoresponse of an AlN-based film bulk acoustic wave resonator (FBAR) is demonstrated. It is found that the FBAR exhibits a resonant frequency downshift under purple light illumination and the magnitude of the frequency downshift increases as the power density increases within the range of 5–40 mW/cm2. A resonant frequency downshift of 1313 KHz is observed under 40 mW/cm2 illumination, corresponding to a minimum detection power of 6.09 nW. A sub-bandgap photoresponse of the AlN thin film is proposed to explain this phenomenon.
Appearance of local strain fields and high electrical conductivity of macro-defects in P+-implanted 4H-SiC
Authors: Ishiji K. , Kawado S. , Hirai Y. , Nagamachi S.
Published: May 2013

We investigated the implantation-temperature-dependence of defect structures of P+-implanted 4H-SiC using synchrotron white-beam x-ray topography, which revealed hitherto unknown defect images in SiC implanted at 300 and 500 °C, though they were not observed in SiC implanted at 30 and 150 °C. These defects corresponded to small bump and saucer-pit defects, called generally “macro-defects,” which were originally located on the initial surface of the SiC epilayer. After subsequent annealing at 1600 °C, the x-ray topographic images of the bump defects were similar to those of threading screw dislocations, but the images of the saucer-pit defects were not visible. Scanning probe microscopy (SPM) revealed that the bump defects had locally higher electrical conductivity (above 70 nA) than the surrounding SiC matrix both after implantation at 500 °C and after annealing at 1600 °C. Lower electrical conductivity (below 1 nA) was observed for the saucer-pit defects. The formation of the specific strain fields around the macro-defects and the appearance of implantation-driven high electrical conductivity at the bump defects are discussed on the basis of the SPM observation and electron probe microanalysis.
Investigation of the role of silver species on spectroscopic features of Sm3+-activated sodium–aluminosilicate glasses via Ag+-Na+ ion exchange
Authors: Li Longji , Yang Yong , Zhou Dacheng , Yang Zhengwen , Xu Xuhui , Qiu Jianbei
Published: May 2013

The introduction of silver into the Sm3+-doped sodium–aluminosilicate glasses prepared by Ag+-Na+ ion exchange leads to the formation of different ionic silver species. Under 270 nm/250 nm excitation, effective enhancement of Sm3+ luminescence is ascribed to radiative energy transfer from isolated Ag+ to Sm3+. Under 355 nm excitation, white light emission was realized by combining red orange light emission of Sm3+ with green light emission of Ag+-Ag+ and blue light emission of (Ag2)+. Silver nanoparticles formed by further heat treatment are effective quenchers of luminescence from the corresponding excited states of Sm3+ ions.
Optimization of graphene dry etching conditions via combined microscopic and spectroscopic analysis
Authors: Prado Mariana C. , Jariwala Deep , Marks Tobin J. , Hersam Mark C.
Published: May 2013

Single-layer graphene structures and devices are commonly defined using reactive ion etching and plasma etching with O2 or Ar as the gaseous etchants. Although optical microscopy and Raman spectroscopy are widely used to determine the appropriate duration of dry etching, additional characterization with atomic force microscopy (AFM) reveals that residual graphene and/or etching byproducts persist beyond the point where the aforementioned methods suggest complete graphene etching. Recognizing that incomplete etching may have deleterious effects on devices and/or downstream processing, AFM characterization is used here to determine optimal etching conditions that eliminate graphene dry etching residues.
High-visibility ghost imaging from artificially generated non-Gaussian intensity fluctuations
Authors: Liu Xue-Feng , Li Ming-Fei , Yao Xu-Ri , Yu Wen-Kai , Zhai Guang-Jie , Wu Ling-An
Published: May 2013

The image quality in ghost imaging is vital in practical applications. Through theoretical analysis, we find that for thermal light the average intensity as well as the fluctuations of an arbitrary incident field can greatly influence the image quality. Based on this, we suggest an easily realizable scheme to improve the visibility by generating speckles of non-Gaussian intensity distributions with a spatial light modulator. Numerical simulation demonstrates that this method can significantly improve the visibility, and the effect on the imaging resolution is also discussed. This method may thus be helpful in promoting the implementation of ghost imaging in real applications.
Determination of electric field at and near the focus of a cylindrical lens for applications in fluorescence microscopy
Authors: Purnapatra Subhajit B. , Mondal Partha P.
Published: May 2013

We present an explicit computable integral solution of the electric field generated at the focal region of a cylindrical lens. This representation is based on vectorial diffraction theory and further enables the computation of the system point spread function of a cylindrical lens. It is assumed that there is no back-scattering and the contribution from the evanescent field is negligible. Stationary phase approximation along with the Fresnel transmission coefficients are employed for evaluating the polarization dependent electric field components. Studies were carried out to determine the polarization effects and to calculate the system resolution. The effect of s −, p − and randomly polarized light is studied on the fixed sample (electric dipole is fixed in space). Proposed approach allows better understanding of electric field effects at the focus of a cylindrical aplanatic system. This opens up future developments in the field of fluorescence microscopy and optical imaging.
Endoscopically guided sinonasal cultures: A direct comparison with maxillary sinus aspirate cultures
Authors: Vogan Jonathan C. , Bolger William E. , Keyes Alan S.
Published: May 2013

Sinusitis is a common medical problem that can at times be challenging to treat. Although most cases respond to empiric therapy, success is not achieved universally. If empiric therapy fails, it is important to identify the causative bacterial pathogen. Antral puncture is the traditional diagnostic method to recover and identify pathogens in sinusitis; however, it remains a painful, invasive test with potential complications. In contrast, rigid sinonasal endoscopy permits recovery of mucopus emanating from the sinus ostia with little pain and few possible complications. Endoscopy also affords important visual information that can confirm or refute a historical/clinical diagnosis of sinusitis. Although previous studies have shown poor correlation between nasal cavity swab cultures and maxillary sinus aspiration cultures, few investigations have compared endoscopically guided middle meatal cultures with cultures obtained from maxillary sinus aspiration. Thirteen patients with maxillary sinusitis in one or both sinuses underwent endoscopically guided culture of the middle meatus and maxillary sinus puncture with aspiration and culture (16 total study samples). Results from the microbiologic analysis were compared. Endoscopically guided middle meatal cultures accurately identified the predominant bacterial pathogen and correlated with the cultures from maxillary sinus aspiration in more than 90% of infections. These preliminary results suggest that endoscopically guided sinonasal cultures hold promise as a viable alternative to maxillary sinus aspiration. Endoscopically guided cultures appear to be an effective, noninvasive diagnostic tool for otolaryngologists managing sinusitis.
Circulating neutrophil CD18 receptor expression and ischemic flap neutrophil infiltration in a guinea pig model
Authors: Dolan Robert , Hartshorn Kevan , Mcavoy Daniel
Published: May 2013

This article demonstrates a correlation between circulating neutrophil CD18 expression, neutrophil infiltration, and varying periods of ischemia induced in guinea pig island skin flaps. Fifty adult female Hartley guinea pigs were equally separated into a control group, a sham group, and ischemic groups of 2, 4, and 10 hours. All, except those in the control group, had single guinea pig island flank skin flaps raised. Systemic neutrophil surface receptor (CD18) expression was analyzed with monoclonal antibodies, and flap skin biopsy specimens were analyzed for neutrophil infiltration. The results show that neutrophil counts and receptor detection increase as flap ischemia increases. However, a trend toward declining receptor expression was observed in the 10‐hour ischemic group. In conclusion, systemic neutrophil adhesion receptor upregulation is correlated with cutaneous flap neutrophil infiltration and ischemia‐reperfusion injury in a guinea pig model. A trend toward declining receptor expression with advanced ischemia was observed.
Tympanostomy tubes and otic suspensions: Do they reach the middle ear space?
Authors: Hebert Richard L. , Vick Michael L. , King Geoffrey E. , Bent John P.
Published: May 2013

The treatment of patients with tympanostomy tubes (TTs) and otorrhea with medicated otic suspensions is well known, but confirmation of penetration into the middle ear is difficult. To address this question, we created an in vitro model of the human head and ear and then tested it with 5 different types of liquid exposure: tap water, soapy water, polymyxin B sulfate (Cortisporin), tobramycin and dexamethasone (TobraDex), and ciprofloxacin (Cipro) suspensions. A positive test result corresponded to liquids entering the middle ear through the TT. No positive test result was elicited with tap water (0/20), but soapy water did enter the middle ear (10/40) and was statistically significant (P = 0.0112). Without the use of slight tragal pressure, Cortisporin, TobraDex, and Cipro drops did not consistently pass through the TT (0/20, 1/25, 1/25). By placing the drops with the addition of tragal pressure, a statistically significant difference was obtained for each solution (20/20, 20/20, and 20/20, respectively [P < 0.0001]). We conclude that with a clean external auditory canal, patent TT, and no middle ear fluid, medicated otic suspensions enter the middle ear only when combined with slight tragal pressure.
Unilateral true vocal fold paralysis: Cause of right‐sided lesions
Authors: Hughes C. Anthony , Troost Sven , Miller Susan , Troost Thomas
Published: May 2013

At the Georgetown University Center for the Voice, 778 patients were referred for evaluation between July 1, 1990, and June 30, 1995. During this 5‐year period, right true vocal fold paralysis or paresis was diagnosed in 24 of these patients (3%). Videostro‐boscopy, voice analysis, and patient records were reviewed. Ages ranged from 23 to 80 years, and sex distribution approximated a 1:1 ratio. The patients presenting symptoms included hoarseness, dysphagia, choking, voice pitch change, voice weakness, fatigability, and breathiness. Sources of the vocal fold dysfunction included iatrogenic, traumatic, central, and infectious causes.
Approaches to the sellar and parasellar region: A retrospective comparison of the endonasal‐transsphenoidal and sublabial‐transsphenoidal approaches
Authors: Spencer William R. , Levine Jonathan M. , Couldwell William T. , Brown‐Wagner Marie , Moscatello Augustine
Published: May 2013

Tumors of the hypophysis are often managed surgically by the neurosurgeon and the otolaryngologist. Three widely used anterior routes to the sella are the endonasal (transcolumellar) transsphenoidal, sublabial transsphenoidal, and transethmoidal approaches. We reviewed the charts of 60 patients who underwent surgery, 42 transcolumellar and 18 sublabial, for sellar and parasellar adenomas and compared the two transsphenoidal approaches. None of the patients in our study underwent the transethmoidal approach. Furthermore, 26 of the patients underwent an extensive interview to assess postoperative progress. Clinically, neither approach had any significant complications, and none of the patients in either group reported significant postoperative morbidity. On the basis of these results, we believe there is minimal difference in patient subjective reports and objective morbidity when comparing the sublabial and transcolumellar approaches.
Comparison of postoperative pain between laser‐assisted uvulopalatoplasty, uvulopalatopharyngoplasty, and radiofrequency volumetric tissue reduction of the palate
Authors: Troell Robert J. , Powell Nelson B. , Riley Robert W. , Li Kasey K. , Guilleminault Christian
Published: May 2013

OBJECTIVES

This study compares the posttreatment discomfort between laser‐assisted uvulopalatoplasty (LAUP), uvulopalatopharyngoplasty (UPPP), and radiofrequency volumetric tissue reduction (RFVTR) of the palate through the use of visual analog pain scales and a quantitative assessment of the analgesic medication taken.

METHODS

In one group, LAUP (n = 10) or UPPP (n = 9) was used to treat patients' snoring or sleep‐disordered breathing (SDB), and the other group underwent RFVTR (n = 22).

RESULTS

The mean numbers of days with pain after RFVTR, LAUP, and UPPP were 2.6, 13.8, and 14.3 days, respectively. Narcotic analgesics were required in the RFVTR, LAUP, and UPPP groups in 9%, 100%, and 100% of the subjects, respectively. The mean number of these days requiring narcotic pain medications for RFVTR, LAUP, and UPPP was 0.2, 11.8, and 12.4 days, whereas the total narcotic equivalent was 0.3, 7.4 and 29.6 days, respectively.

CONCLUSION

RFVTR of the soft palate produced less posttreatment pain than LAUP or UPPP. LAUP and UPPP appeared to show little difference in the severity or duration of posttreatment discomfort.
Tumor size and pretreatment speech and swallowing in patients with resectable tumors
Authors: Colangelo Laura A. , Logemann Jeri A. , Rademaker Alfred W.
Published: May 2013

The pretreatment relationship of tumor burden to speech and swallowing function in 230 patients with oral or oropharyngeal cancer before surgery was assessed. Reduced articulation, reduced conversational understandability, or self‐reported dysphagia were present in at least 34% of patients before treatment. Videofluoroscopy showed at least 9% of patients had reduced swallowing efficiency on liquid, paste, or cookie boluses. By use of regression techniques, the percentages of the oral tongue and of the anterior floor of mouth affected by neoplasm were found to be significantly related to reduced articulation; T stage and the percentage of the oral tongue affected with tumor were mildly related to reduced understandability; tumor volume and having soft palate affected by neoplasm were significantly related to self‐reported dysphagia; and percentages of affected oral tongue and of affected tongue base were significantly related to reduced swallowing efficiency. Tumor burden may contribute to functional deficits at diagnosis in patients who have resectable tumors.
Intraoperative radiolymphoscintigraphy for detection of occult nodal metastasis in patients with head and neck squamous cell carcinoma
Authors: Zitsch Robert P. , Todd Daniel W. , Renner Gregory J. , Singh Amolak
Published: May 2013

OBJECTIVES

We sought to determine the feasibility and utility of intraoperative radiolymphoscintigraphy as a screening procedure for the detection of occult metastatic disease in selected cases of head and neck squamous cell carcinoma (HNSCC).

METHODS

Patients with accessible primary HNSCC and no evidence of metastatic disease who were already undergoing planned surgical resection of the primary tumor and elective neck dissection met the inclusion criteria. Before resection, a handheld gamma probe was used to find the radiolabeled sentinel lymph node (SLN). The neck specimen was examined ex vivo by using the gamma probe; the SLN or SLNs were dissected free from the specimen and sent separately for histopathologic examination.

RESULTS

At least one SLN was identified in all patients enrolled thus far. Four patients had microscopic carcinoma found in the SLN. Two of these had cancer only in the SLN, and two had disease both in the SLN and the remaining specimen.

CONCLUSIONS

Intraoperative radiolymphoscintigraphy appears to be a feasible and promising procedure to aid the surgeon in more accurately detecting occult metastatic HNSCC.
Comparison of open, percutaneous, and translaryngeal tracheostomies
Authors: Maccallum Patricia L. , Parnes Lorne S. , Sharpe Michael D. , Harris Chris
Published: May 2013

INTRODUCTION

With 3 tracheostomy techniques currently available, controversy exists regarding which is safest and most economical. Percutaneous (PDT) and the new translaryngeal (TLT) tracheostomies are cited as more cost‐effective than the traditional open surgical procedure because they are bedside techniques. Our objective was to compare the perioperative and postoperative complications of the 3 techniques.

STUDY DESIGN

This was a prospective trial involving 100 consecutive patients who underwent tracheostomy between April and December of 1997 at the London Health Sciences Centre and St Joseph's Health Centre in London, Canada.

RESULTS

Fifty open tracheostomies were performed. Indications included prolonged ventilation (n = 42), airway protection (n = 5), pulmonary hygiene (n = 2), and sleep apnea (n = 1). A tension pneumothorax was the one significant intraoperative complication. Fifteen postoperative complications occurred, most notable of which was a 2‐L hemorrhage at 24 hours. Thirty‐seven TLTs were performed, 20 in patients with coagulopathy. Indications were prolonged intubation (n = 27), airway protection (n = 9), and pulmonary hygiene (n = 1). One intraoperative complication of accidental decannulation occurred. One postoperative complication, a pretracheal abscess, occurred in a decannulated transplant patient 2 weeks after the procedure. Thirteen PDTs were performed. Indications were prolonged intubation (n = 6), airway protection (n = 6), and tracheal toilet (n = 1). No significant complications occurred.

CONCLUSIONS

TLT and PDT have fewer complications than the traditional open technique. TLT appears to have the greatest utility in the coagulopathic patient.
Use of computed tomography in the assessment of mandibular invasion in carcinoma of the retromolar trigone
Authors: Lane Andrew P. , Buckmire Robert A. , Mukherji Suresh K. , Pillsbury Harold C. , Meredith Scott D.
Published: May 2013

Carcinomas originating in the retromolar trigone (RMT) are uncommon and characterized by early spread. Determination of mandibular invasion is significant for planning therapy and determining prognosis. For oral cavity cancers in general, CT is reasonably accurate in assessing bone invasion. However, there is a paucity of information specifically addressing the value of CT in the RMT. In this study, the records of patients with biopsy‐proven RMT carcinomas treated between 1984 and 1998 were reviewed with attention to preoperative CT scans and histopathologic findings during surgery. Half of the patients who were treated with primary resection had mandibular invasion. Bone invasion was not identified radiographically in 27% of patients with preoperative CT scans. The sensitivity of CT for bone involvement in RMT cancers was 50%, with a negative predictive value of 61.1%. The positive predictive value was 91.1%. These findings suggest that CT is a useful, but potentially inaccurate, predictor of bone invasion in the RMT.
Short‐ and long‐term outcomes of canalith repositioning for benign paroxysmal positional vertigo
Authors: Nunez Robert A. , Cass Stephen P. , Furman Joseph M.
Published: May 2013

This is a prospective, nonrandomized study of the canalith repositioning procedure (CRP) for treatment of benign paroxysmal positional vertigo (BPPV). CRP was used to treat 168 patients with BPPV. Patient data were gathered by yearly telephone interviews to determine whether symptoms of position‐induced vertigo had returned. After 1 or 2 treatment sessions 91.3% of patients reported complete symptom resolution. Average follow‐up for the study population after the initial treatment was 26 months. A recurrence rate of 26.8% was found among those patients who initially reported resolution of symptoms after CRP. Application of recurrence data to a Kaplan‐Meier estimation suggests a 15% recurrence rate per year of BPPV, with a 50% recurrence rate of BPPV at 40 months after treatment. There was no significant association between cure or recurrence rate and sex, age, duration of symptoms, presumed cause, or treating physician.
Vestibular dysfunction in Gulf War syndrome
Authors: Roland Peter S. , Haley Robert W. , Yellin Wendy , Owens Kris , Shoup Angela G. , Holt G. Richard
Published: May 2013

METHODS

Vestibular complaints of Gulf War veterans were characterized by a nested case‐control study of 23 veterans with 3 different Gulf War syndromes and 20 matched control subjects. All subjects completed a standardized symptom questionnaire and underwent standard audiovestibular tests administered by audiologists blinded to group identities.

RESULTS

The prevalence of reported dizzy spells was higher in veterans with Gulf War syndromes 1 (100%), 2 (85%), and 3 (100%) than in controls (25%, P < 0.0001). Dizzy spells were more frequent, lasted longer, and involved a wider variety of accompanying symptoms in veterans with syndrome 2 than in those with syndromes 1 and 3. Audiovestibular testing showed greater interocular asymmetry of nystagmic velocity on sinusoidal harmonic acceleration in syndromes 1 (P = 0.015) and 2 (P = 0.002), greater asymmetry of saccadic velocity in syndrome 2 (P = 0.4), diminished nystagmic velocity after caloric stimulation bilaterally in syndrome 3 (P = 0.02 to 0.04), more subjects with pathologic nystagmus (P = 0.09), and greater interside asymmetry of wave I to III interpeak latency on auditory brain stem response in syndromes 1 (P = 0.005) and 2 (P = 0.07). Asymmetry of gain on sinusoidal harmonic acceleration and pathologic nystagmus were most strongly associated with symptoms of paroxysmal vertigo (P = 0.002 and 0.07, respectively); asymmetry of saccadic velocity, with the severity of vertigo (P = 0.004); and abnormal caloric response, with chronic dysequilibrium (P = 0.006).

CONCLUSIONS

The findings are compatible with a subtle neurologic injury from organophosphate‐induced delayed neurotoxicity.
Clinical experiences of removing foreign bodies in the airway and esophagus with a rigid endoscope: A series of 3217 cases from 1970 to 1996
Authors: Hsu Wei‐Chung , Sheen Tzung‐Shiahn , Lin Chia‐Der , Tan Ching‐Ting , Yeh Te‐Huei , Lee Shiann‐Yann
Published: May 2013

This study examined 11,333 rigid endoscopy procedures performed in the Department of Otolaryngology, National Taiwan University Hospital, during a 27‐year period from 1970 to 1996. Among these cases, 3217 were performed to remove foreign bodies from the airway (459 cases, 14.3%) and esophagus (2758 cases, 85.7%). Retrospective analysis of these data revealed that peanuts (217 cases) and animal bones (1184 cases) were the most frequent foreign bodies encountered in the airway and esophagus, respectively. The successful rate of removal of these foreign bodies was 99.9% (3213/3217). The complication rate was only 0.2% (8/3217), and the mortality rate was less than 0.1% (2/3217). On the basis of these results, we conclude that foreign bodies in the airway and esophagus can be removed safely under direct visualization through rigid endoscopy with relatively few complications. A significant finding in this study is the declining trend in the number of cases in recent years. Despite the decline in the number of procedures, endoscopic removal of foreign bodies remains as a vital skill of the aerodigestive tract surgeon.
Complications of postoperative radiation therapy after partial laryngectomy in supraglottic cancer: A long‐term evaluation
Authors: Laccourreye Ollivier , Hans StÉPhane , Borzog‐Grayeli Ali , Maulard‐Durdux Catherine , Brasnu Daniel , Housset Martin
Published: May 2013

This retrospective study, based on a series of 90 patients with invasive squamous cell carcinoma of the supraglottis, was designed to document the functional outcome and complications after postoperative radiation therapy following partial laryngeal surgery. The surgical procedure was a standard supraglottic laryngectomy in 62 patients and a supracricoid partial laryngectomy in 28 patients. All of the patients had an unremarkable postoperative course and achieved locoregional control. The average dose delivered to the remaining larynx was 51.2 Gy (range 25‐71 Gy). The average dose delivered to the neck was 50.6 Gy (range 2270 Gy). The patients were treated at 180‐cGy per fractions in a continuous course technique with a cobalt 60 beam. In 5 patients (5.5%) complications led to cessation of postoperative radiation therapy, and the total dose delivered to the remaining larynx and neck was less than 40 Gy. All patients were followed up for a minimum of 10 years or until death. The 5‐, 10‐, and 15‐year actuarial survival estimates were 71.5%, 44.3%, and 36.3%, respectively. The 5‐, 10‐, and 15‐year actuarial severe complication estimates were all 11.2%. Overall, severe complications occurred in 15 patients. Severe complications led to death in 3 patients (3.3%), permanent gastrostomy in 3 (3.3%), and permanent tracheostomy in 1 (1.1%). A severe complication never resulted in completion of total laryngectomy. In univariate analysis, the mean dose delivered to the larynx was the only variable statistically related to the incidence of a severe complication. The mean dose delivered to the larynx was statistically higher (P= 0.014) in patients who had severe complications (60 Gy) than in patients who did not (50 Gy).
Surgical treatment of labyrinthine fistula caused by cholesteatoma
Authors: Soda‐Merhy Antonio , Betancourt‐SuÁRez Miguel Angel
Published: May 2013

In a 144‐month period, 27 cases of labyrinthine fistula (LF) were seen, and 360 mastoid operations were performed; the LF prevalence was 7.5%. Primary symptoms were hypoacusis, otorrhea, vertigo, tinnitus, and otalgia. All patients underwent preoperative CT scans and preoperative audiometry. LF diagnosis was made before surgery for 93% of patients on the basis of symptoms, signs, and imaging studies. With respect to surgical technique, the canal‐wall‐down procedure was performed in 92%, and the canal‐wall‐up procedure was performed in 8%. In 88% of patients the fistula was located in the horizontal semicircular canal. In 96% of patients the cholesteatoma matrix was removed, and the fistula was sealed; in 4% of patients the matrix was left. With a follow‐up of 13 years, vertigo disappeared in 96% of patients, and hearing remained unchanged in 70% of patients. Further complications of chronic otitis media existed in approximately half of the patients with LF. Open surgery with removal of the cholesteatoma matrix and sealing of the fistula with temporalis fascia in a canal‐wall‐down manner is a safe procedure that can make vertigo disappear and helps to preserve cochlear function.