bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of large elastodynamic earthquakes on complex fault systems
Authors: Shaw Bruce E.
Published: September 2004

One of the biggest assumptions, and a source of some of the biggest uncertainties in earthquake hazard estimation is the role of fault segmentation in controlling large earthquake ruptures. Here we apply a new model which produces sequences of elastodynamic earthquake events on complex segmented fault systems, and use these simulations to quantify the variation of large events. We find a number of important systematic effects of segment geometry on the slip variation and the repeat time variation of large events, including an increase in variation at the ends of segments and a decrease in variation for the longest segments.
Streaks, multiplets, and holes: High‐resolution spatio‐temporal behavior of Parkfield seismicity
Authors: Waldhauser F. , Ellsworth W. L. , Schaff D. P. , Cole A.
Published: September 2004

Double‐difference locations of ∼8000 earthquakes from 1969–2002 on the Parkfield section of the San Andreas Fault reveal detailed fault structures and seismicity that is, although complex, highly organized in both space and time. Distinctive features of the seismicity include: 1) multiple recurrence of earthquakes of the same size at precisely the same location on the fault (multiplets), implying frictional or geometric controls on their location and size; 2) sub‐horizontal alignments of hypocenters along the fault plane (streaks), suggestive of rheological transitions within the fault zone and/or stress concentrations between locked and creeping areas; 3) regions devoid of microearthquakes with typical dimensions of 1–5 km (holes), one of which contains the M6 1966 Parkfield earthquake hypocenter. These features represent long lived structures that persist through many cycles of individual events.
A pressure‐driven South China Sea Warm Current
Authors: Hsueh Y. , Zhong Liejun
Published: September 2004

Imposed pressure along the continental shelf break is shown to generate, in accordance with the arrested topographic wave (ATW) theory, a steady state flow that resembles the South China Sea Warm Current (SCSWC), flowing northeastward year‐round along the outer continental shelf off the southern coast of China. The requisite shelf‐break pressure distribution arises from the collision with the continental slope near the Dongsha Islands at about 116E and 21N, of the Kuroshio that has intruded into the South China Sea through the southern part of the Luzon Strait. The flow deflection following the collision creates the South China Sea Branch of Kuroshio (SCSBK) as a splinter current to the southwest, while the mainstream of the Kuroshio veers to the northeast and eventually exits the South China Sea through the northern part of the Luzon Strait. A channel flow model driven by an inflow‐outflow condition at one end and closed at the other suggests the SCSBK may be feeding the SCSWC all along the shelf break through a weak onshore flow driven by the gradual drop in pressure in the SCSBK due to bottom friction. The SCSWC and SCSBK flow combination is also found in a Bryan‐Cox model of the northern South China Sea. The SCSWC in the Bryan‐Cox model thrives in summer and survives only near the shelf break during the winter when the northeast monsoon wind dominates.
Thermalization of fast O(1D) atoms in the stratosphere and mesosphere
Authors: Kharchenko V. , Dalgarno A.
Published: September 2004

The thermalization of metastable oxygen atoms in the stratosphere and mesosphere has been investigated. Non‐Maxwellian O(1D) distributions have been calculated at altitudes of 25 and 50 km taking into account the energy transfer and quenching collisions of fast O(1D) atoms with the ambient gas. The evolution of the energy distributions of nascent metastable oxygen atoms, produced by ozone photolysis, has been determined by solving the time‐dependent Boltzmann equation. The time‐dependent and steady state O(1D) distributions have been computed and used for calculations of parameters characterizing O(1D) thermalization and quenching in the stratosphere and mesosphere. The steady state O(1D) distributions contain 3–5% of nonthermal atoms, fractions which are significantly larger than those of nonthermal ground state oxygen or nitrogen atoms. The effective temperatures of the non‐Maxwellian distributions have been found to be 14% and 33% higher than thermal temperatures of the ambient gas at 25 and 50 km. The nonequilibrium rate coefficients and yields of NO molecules in the atmospheric reaction O(1D) + N2O corresponding to the non‐Maxwellian distributions of O(1D) atoms have been calculated.
Separating chemistry and transport effects in two‐dimensional models
Authors: Weisenstein Debra K. , Eluszkiewicz Janusz , Ko Malcolm K. W. , Scott Courtney J. , Jackman Charles H. , Fleming Eric L. , Considine David B. , Kinnison Douglas E. , Connell Peter S. , Rotman Douglas A.
Published: September 2004

Representation of transport in numerical models is known to be a major uncertainty in modeling of the atmosphere. Models also differ in their treatment of gas phase and heterogeneous chemistry. This paper will describe a quantitative approach to diagnosing the source of intermodel differences in ozone assessment calculations. Our approach is applied to diagnosing the differences between two‐dimensional (2‐D) models from Atmospheric and Environmental Research, the NASA Goddard Space Flight Center, and the Lawrence Livermore National Laboratory. Surprisingly, we find that differences due to chemical formulation are often as large as those due to transport, despite the fact that all models use the same set of reaction rate coefficients. These differences are particularly large when polar stratospheric cloud (PSC) processes are included in the models, though differences due to photolysis rates and details of the sulfate chemistry are also apparent. Perturbation calculations for a scenario including supersonic commercial aircraft operating in the 2015 stratosphere reveal that differences in the accumulation of H2O and NOy emitted by aircraft are due almost entirely to transport, while differences in ozone due to chemical formulation are evident in the lower stratosphere even without differences in H2O and NOy and without PSCs. By demonstrating a capability of separating transport and chemical differences, it is hoped that the results described in this paper will stimulate analogous studies with other models and will thus lead to a deeper understanding of intermodel similarities and differences, along with a means to quantify uncertainties in model predictions of atmospheric response to perturbations.
Biochemical Changes Induced in Liver and Serum of Aflatoxin B1‐Treated Male Wistar Rats: Preventive Effect of Picroliv
Authors: Rastogi Ravi , Srivastava Arvind Kumar , Rastogi Anil Kumar
Published: September 2004

Abstract: Administration of aflatoxin B1 to rats (2 mg/kg intraperitoneally) caused significant increase in the activities of γ‐glutamyl transpeptidase, 5′‐nucleotidase, acid phosphatase, acid ribonuclease as well as content of lipid peroxides in liver after six weeks. However, the activities of succinate dehydrogenase, glucose‐6‐phosphatase, catalase, superoxide dismutase, glutathione‐S‐transferase, glutathione peroxidase and glutathione reductase in liver were decreased. The levels of glycogen and reduced glutathione were also decreased. There were significant elevations in the levels of serum transaminases, phosphatases (acid and alkaline), dehydrogenases (sorbitol, lactate and glutamate) and bilirubin following aflatoxin B1 administration. Picroliv (25 mg/kg/day orally for six weeks), an iridoid glycoside isolated from the roots and rhizomes of Picrorhiza kurroa, significantly prevented the biochemical changes induced by aflatoxin B1.
Wide-bandgap high-mobility ZnO thin-film transistors produced at room temperature
Authors: Fortunato Elvira M. C. , Barquinha Pedro M. C. , Pimentel Ana C. M. B. G. , Gonçalves Alexandra M. F. , Marques António J. S. , Martins Rodrigo F. P. , Pereira Luis M.N.
Published: September 2004

We report high-performance ZnO thin-film transistor (ZnO-TFT) fabricated by rf magnetron sputtering at room temperature with a bottom gate configuration. The ZnO-TFT operates in the enhancement mode with a threshold voltage of 19V, a saturation mobility of 27cm2∕Vs, a gate voltage swing of 1.39V∕decade and an on/off ratio of 3×105. The ZnO-TFT presents an average optical transmission (including the glass substrate) of 80% in the visible part of the spectrum. The combination of transparency, high mobility, and room-temperature processing makes the ZnO-TFT a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics.
A spin injector
Authors: Chen Zhigao , Wang Baigeng , Xing D. Y. , Wang Jian
Published: September 2004

We theoretically put forward a spin injector, which consists of a three-terminal ferromagnetic-metal (FM) nonmagnetic-semiconductor (NS)-superconductor (SC) mesoscopic hybrid system. This device can inject not only the spin-up current but also the pure spin current into the NS lead. The crossed Andreev reflection plays a key role in this device. Such a spin injector may be realized within the reach of the present-day technology.
Systematic study of polarized electron emission from strained GaAs∕GaAsP superlattice photocathodes
Authors: Maruyama T. , Luh D.-A. , Brachmann A. , Clendenin J. E. , Garwin E. L. , Harvey S. , Jiang J. , Kirby R. E. , Prescott C. Y. , Prepost R. , Moy A. M.
Published: September 2004

Spin-polarized electron photoemission has been studied for GaAs∕GaAs1−xPx strained superlattice cathodes grown by gas-source molecular beam epitaxy. The superlattice structural parameters are systematically varied to optimize the photoemission characteristics. The heavy-hole and light-hole transitions are reproducibly observed in quantum efficiency spectra, enabling direct measurement of the band energies and the energy splitting. Electron-spin polarization as high as 86% with over 1% quantum efficiency has been observed.
Use of extended and prepared reference objects in experimental Fourier transform x-ray holography
Authors: He H. , Weierstall U. , Spence J. C. H. , Howells M. , Padmore H. A. , Marchesini S. , Chapman H. N.
Published: September 2004

The use of one or more gold nanoballs as reference objects for Fourier transform holography (FTH) is analyzed using experimental soft x-ray diffraction from objects consisting of separated clusters of these balls. The holograms are deconvoluted against ball reference objects to invert to images, in combination with a Wiener filter to control noise. A resolution of ∼30nm, smaller than one ball, is obtained even if a large cluster of balls is used as the reference, giving the best resolution yet obtained by x-ray FTH. Methods of dealing with missing data due to a beamstop are discussed. Practical prepared objects which satisfy the FTH condition are suggested, and methods of forming them described.
Magnetoelectric interactions in hot-pressed nickel zinc ferrite and lead zirconante titanate composites
Authors: Srinivasan G. , DeVreugd C. P. , Flattery C. S. , Laletsin V. M. , Paddubnaya N.
Published: September 2004

The synthesis by hot pressing and wide-band (10Hz–1MHz) magnetoelectric (ME) characterization of bulk composites of nickel zinc ferrite Ni1−xZnxFe2O4 (NZFO) (x=0–0.5) and lead zirconate titanate (PZT) are reported. Hot-pressed samples show an order of magnitude improvement in ME voltage coefficient compared to sintered samples. Frequency dependence of ME coefficients show a three order of magnitude enhancement at electromechanical resonance. The ME coupling is maximum for samples with equal volume of ferrite and PZT. The strongest ME interactions are measured for samples of NZFO (x=0.2) and PZT.
In situ observation of electromigration-induced void migration in dual-damascene Cu interconnect structures
Authors: Vairagar A. V. , Mhaisalkar S. G. , Krishnamoorthy Ahila , Tu K. N. , Gusak A. M. , Meyer Moritz Andreas , Zschech Ehrenfried
Published: September 2004

In situ electromigration experiments were carried out to study electromigration-induced failure in the upper and lower layers in dual-damascene Cu test structures. The observations revealed electromigration-induced void movement along the Cu/dielectric cap interface. It supports the premise that Cu∕Si3N4 interface acts as the dominant electromigration path. However, the observed void nucleation occurs in the Cu∕Si3N4 interface at locations which are far from the cathode, and void movement along the Cu∕Si3N4 interface in opposite direction of electron flow eventually causes void agglomeration at the via in the cathode end. The different electromigration behaviors of the upper and lower layer dual-damascene structures are discussed.
Formation of monodisperse bubbles in a microfluidic flow-focusing device
Authors: Garstecki Piotr , Gitlin Irina , DiLuzio Willow , Whitesides George M. , Kumacheva Eugenia , Stone Howard A.
Published: September 2004

This letter describes a method for generating monodisperse gaseous bubbles in a microfluidic flow-focusing device. The bubbles can be obtained in a range of diameters from 10 to 1000μm. The volume Vb of the bubbles scales with the flow rate q and the viscosity μ of the liquid, and the pressure p of the gas stream as Vb∝p∕qμ. This method allows simultaneous, independent control of the size of the individual bubbles and volume fraction of the dispersed phase. Under appropriate conditions, bubbles self-assemble into highly ordered, flowing lattices. Structures of these lattices can be adjusted dynamically by changing the flow parameters.
Role of thin Fe catalyst in the synthesis of double- and single-wall carbon nanotubes via microwave chemical vapor deposition
Authors: Wang Y. Y. , Gupta S. , Nemanich R. J.
Published: September 2004

Synthesis of vertically aligned small diameter (single- and double-wall) carbon nanotube films on thermally oxidized n+-Si(001) wafers, with acetylene diluted with ammonia gas mixture using a microwave plasma-assisted chemical vapor deposition technique, is reported. Experiments show that by continuous reduction in the thickness of the iron catalyst film to ∼0.3–0.5nm, or alternately, smaller catalyst particles produces hollow concentric tubes with a fewer number of walls. Double- and single-wall carbon nanotubes with diameters ranging from 1 to 5nm were identified using transmission electron microscopy and Raman spectroscopy. A relatively higher deposition temperature (∼850°C) in conjunction with a controlled catalyst and rapid growth (<40s) allowed for the growth of well-graphitized, high areal density (∼1012-1013∕cm2) nanotubes with reduced amorphous carbon and iron. Our results also indicate that the base growth is the most appropriate model to describe the growth mechanism for the nanotube films.
A miniaturized biconvex quartz-crystal microbalance with large-radius spherical thickness distribution
Authors: Li Li , Esashi Masayoshi , Abe Takashi
Published: September 2004

A miniaturized biconvex quartz-crystal microbalance (QCM) with large-radius spherical thickness distribution was fabricated by reactive ion etching (RIE) and photoresist reflow with solvent vapor technology. A conventional polishing method could not manufacture the miniaturized, spherically convex shape, which is necessary to suppress a spurious mode and obtain a high Q factor. Not only can the large-radius spherical convex shape be achieved by this technology, but also miniaturization and batch fabrication. The Q factor of the fabricated QCM (80 000) is two times higher than that of the planar QCM, and the spurious mode around the fundamental vibration mode is suppressed very well. It also has superior resonant characteristic under the viscoelastic liquid.
Optical microfluidics
Authors: Kotz K. T. , Noble K. A. , Faris G. W.
Published: September 2004

We present a method for the control of small droplets based on the thermal Marangoni effect using laser heating. With this approach, droplets covering five orders of magnitude in volume (∼1.7μL to 14 pL), immersed in decanol, were moved on an unmodified polystyrene surface, with speeds of up to 3 mm/s. When two droplets were brought into contact, they spontaneously fused and rapidly mixed in less than 33 ms. This optically addressed microfluidic approach has many advantages for microfluidic transport, including exceptional reconfigurability, low intersample contamination, large volume range, extremely simple substrates, no electrical connections, and ready scaling to large arrays.
Liquid crystal photoalignment material based on chloromethylated polyimide
Authors: Zhong Zhen-Xin , Li Xiangdan , Lee Seung Hee , Lee Myong-Hoon
Published: September 2004

We report a liquid crystal photoalignment material with high photosensitivity and excellent thermal stability. The chloromethylated aromatic polyimide exhibited defect-free homogeneous alignment of liquid crystals upon irradiation of polarized deep ultraviolet (UV) for 50s. The aligning ability of the film was retained up to 210°C, and the cell containing liquid crystals could be stored at 85°C for more than 14 days without any deterioration. FT-IR and UV–vis spectra confirmed that the alignment was induced by photodecomposition of polyimide, drastically accelerated by the introduction of chloromethyl side group.
Porous tracks along wakes of swift uranium ions in polyimide
Authors: Abu Saleh Sameer , Eyal Yehuda
Published: September 2004

Density decreases of 64% along ∼6-nm-diam ion damage trails, latent ion tracks, created through a 50-μm-thick polyimide foil by penetrating 2.64GeV U ions, have been measured by small-angle x-ray scattering. This first derived morphology is attributed to local polymer degradation under intense electronic energy deposition, and subsequent transport and release of gaseous and volatile alteration products through the low-density tracks. Free volume undoubtedly accelerates preferential through-track permeability of inert and corrosive agents, a property that is important for track applications.
Biochemical identification of Argonaute 2 as the sole protein required for RNA-induced silencing complex activity
Authors: Rand Tim A. , Ginalski Krzysztof , Grishin Nick V. , Wang Xiaodong
Published: September 2004

RNA interference is carried out by the small double-stranded RNA-induced silencing complex (RISC). The RISC-bound small RNA guides the RISC complex to identify and cleave mRNAs with complementary sequences. The proteins that make up the RISC complex and cleave mRNA have not been unequivocally defined. Here, we report the biochemical purification of RISC activity to homogeneity from
Drosophila
Schnieder 2 cell extracts. Argonaute 2 (Ago-2) is the sole protein component present in the purified, functional RISC. By using a bioinformatics method that combines sequence-profile analysis with predicted protein secondary structure, we found homology between the PIWI domain of Ago-2 and endonuclease V and identified potential active-site amino acid residues within the PIWI domain of Ago-2.
Experimental Study of Subchronic Toxicity of Lanthanum Nitrate on Liver in Rats
Authors: Chen Dong , Liu Ying , Chen Ai-Jun , Nie Yu-Xiu
Published: September 2004

Wistar rats were divided into six groups, which were given La(NO3)3 at 20.0, 10.0, 2.0, 0.2, and 0.1 mg/kg, and the control group, which was given physiological saline, respectively, for six months. Pathological changes of liver were observed via light microscopy and transmission electron microscopy. Glutamic-oxalacetic transaminase, glutamic-pyruvic transitanase, gamma-glutamyl transferase, and alkline phosphatase activities in the serum were measured. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde of liver were determined. The metabolic accumulation of lanthanum in rat liver was investigated via inductively coupled plasma mass spectrometry. Results showed no abnormal biochemical changes. In the group of 20.0 mg/kg La(NO3)3, there were loss of weight, decrease of glycogen in the hepatocytes, denser matrix of the mitochondria, and deformation of the nuclei of some hepatocytes with different degrees and infiltration of inflammatory cells in the portal area. The higher was the dose, the higher was the number of bodies contain high electronic dense gravel-like granules, and secondary lysosomes with dense bodies were observed. In the group fed 0.1 mg/kg La(NO3)3, intracellular glycogen showed an increasing tendency, particularly increased animal growth and increased activities of SOD and GSH-Px. The content of La in the liver increased regularly with increase in close and time of administration. The results further proved that low-dose La(NO3)3 produced some specific biologic effects. This study illustrated the influence of La(NO3)3 on rat liver at cellular and subcellular levels and it provides an experimental basis for the purpose of setting a reasonable standard for safely utilizing rare earth elements.
Adaptive Responses Account for the β-Curve—Hormesis is Linked to Acquired Tolerance
Authors: Stebbing A. R. D.
Published: September 2004

To date there is no single shared property of the various physical and chemical agents that elicit the β-curve to account for its form, leading to the proposition that hormesis is a consequence of the nonspecificity of adaptive responses. It is argued that adaptive responses to toxic agents may be expected to follow the β-curve. Four kinds of examples are reviewed (enzyme activity, sequestration and repair, and reproductive and homeostatic responses) that corroborate this proposition. The homeostasis example (incorporating homeorhesis) is considered in more detail, using the author's published hydroid experimental growth data, to show that both the α-and β-curves are satisfactorily explained in this way. Many consider that hormesis is merely due to regulatory overcorrections, but it is proposed that it is a consequence of adaptations of the rate-sensitive growth control mechanism (homeorhesis) to sustained levels of inhibition to which the growth control mechanism adapts. In response to low levels of inhibition, upward adjustment of preferred growth rates confers greater resistance to inhibition, with growth hormesis as a cumulative byproduct.
Decomposition Analyses Applied to a Complex Ultradian Biorhythm: The Oscillating NADH Oxidase Activity of Plasma Membranes Having a Potential Time-Keeping (Clock) Function
Authors: Foster Ken , Anwar Nasim , Pogue Rhea , Morré Dorothy M. , Keenan T. W. , Morré D. James
Published: September 2004

Seasonal decomposition analyses were applied to the statistical evaluation of an oscillating activity for a plasma membrane NADH oxidase activity with a temperature compensated period of 24 min. The decomposition fits were used to validate the cyclic oscillatory pattern. Three measured values, average percentage error (MAPE), a measure of the periodic oscillation, mean average deviation (MAD), a measure of the absolute average deviations from the fitted values, and mean standard deviation (MSD), the measure of standard deviation from the fitted values plus R-squared and the Henriksson-Merton p value were used to evaluate accuracy.

Decomposition was carried out by fitting a trend line to the data, then detrending the data if necessary, by subtracting the trend component. The data, with or without detrending, were then smoothed by subtracting a centered moving average of length equal to the period length determined by Fourier analysis. Finally, the time series were decomposed into cyclic and error components. The findings not only validate the periodic nature of the major oscillations but suggest, as well, that the minor intervening fluctuations also recur within each period with a reproducible pattern of recurrence.
Nonlinear Dose-Response Relationship in the Immune System following Exposure to Ionizing Radiation: Mechanisms and Implications
Authors: Liu Shu-Zheng
Published: September 2004

The health effects of low-dose radiation (LDR) have been the concern of the academic spheres, regulatory bodies, governments, and the public. Among these effects, the most important is carcinogenesis. In view of the importance of immune surveillance in cancer control, the dose-response relationship of the changes in different cell types of the immune system after whole-body irradiation is analyzed on the basis of systemic data from the author's laboratory in combination with recent reports in the literature. For T lymphocytes J- or inverted J-shaped curves are usually demonstrated after irradiation, while for macrophages dose-response curves of chiefly stimulation with irregular patterns are often observed. The intercellular reactions between the antigen presenting cell (APC) and T lymphocyte (TLC) in the immunologic synapse via expression of surface molecules and secretion of cytokines by the two cell types after different doses of radiation are illustrated. The different pathways of signal transduction thus facilitated in the T lymphocyte by different doses of radiation are analyzed to explain the mechanism of the phenomenon of low-dose stimulation and high-dose suppression of immunity. Experimental and clinical data are cited to show that LDR retards tumor growth, reduces metastasis, increases the efficacy of conventional radiotherapy and chemotherapy as well as alleviates the suppression of immunity due to tumor burden. The incidence of thymic lymphoma after high-dose radiation is lowered by preexposure to low-dose radiation, and its mechanism is supposed to be related to the stimulation of anticancer immunity induced by low-dose radiation. Recent reports on lowering of standardized cancer mortality rate and all cause death rate of cohorts occupationally exposed to low-dose radiation from the US, UK, and Canada are cited.
RANKL-induced DC-STAMP Is Essential for Osteoclastogenesis
Authors: Kukita Toshio , Wada Naohisa , Kukita Akiko , Kakimoto Takashi , Sandra Ferry , Toh Kazuko , Nagata Kengo , Iijima Tadahiko , Horiuchi Madoka , Matsusaki Hiromi , Hieshima Kunio , Yoshie Osamu , Nomiyama Hisayuki
Published: September 2004

Osteoclasts are bone-resorbing, multinucleated giant cells that are essential for bone remodeling and are formed through cell fusion of mononuclear precursor cells. Although receptor activator of nuclear factor–κB ligand (RANKL) has been demonstrated to be an important osteoclastogenic cytokine, the cell surface molecules involved in osteoclastogenesis are mostly unknown. Here, we report that the seven-transmembrane receptor-like molecule, dendritic cell–specific transmembrane protein (DC-STAMP) is involved in osteoclastogenesis. Expression of DC-STAMP is rapidly induced in osteoclast precursor cells by RANKL and other osteoclastogenic stimulations. Targeted inhibition of DC-STAMP by small interfering RNAs and specific antibody markedly suppressed the formation of multinucleated osteoclast-like cells. Overexpression of DC-STAMP enhanced osteoclastogenesis in the presence of RANKL. Furthermore, DC-STAMP directly induced the expression of the osteoclast marker tartrate-resistant acid phosphatase. These data demonstrate for the first time that DC-STAMP has an essential role in osteoclastogenesis.
Varicella-Zoster Virus Transfer to Skin by T Cells and Modulation of Viral Replication by Epidermal Cell Interferon-α
Authors: Ku Chia-Chi , Zerboni Leigh , Ito Hideki , Graham Brad S. , Wallace Mark , Arvin Ann M.
Published: September 2004

Primary infection with varicella-zoster virus (VZV) causes the characteristic syndrome of varicella, or chickenpox. Experiments in severe combined immunodeficiency mice with human skin grafts (SCIDhu mice) indicate that VZV infection of T cells can mediate transfer of infectious virus to skin. VZV-infected T cells reached epithelial sites of replication within 24 h after entering the circulation. Memory CD4+ T cells were the predominant population recovered from skin in SCIDhu mice given uninfected or infected mononuclear cells, suggesting that immune surveillance by memory T cells may facilitate VZV transfer. The increased susceptibility of memory T cells to VZV infection may further enhance their role in VZV pathogenesis. During VZV skin infection, viral gene products down-regulated interferon-α to permit focal replication, whereas adjacent epidermal cells mounted a potent interferon-α response against cell–cell spread. Interleukin-1α, although activated in VZV-infected cells, did not trigger expression of endothelial adhesion molecules, thereby avoiding early recruitment of inflammatory cells. The prolonged varicella incubation period appears to represent the time required for VZV to overcome antiviral responses of epidermal cells and generate vesicles at the skin surface. Modulation of VZV replication by cutaneous innate immunity may avoid an incapacitating infection of the host that would limit opportunities for VZV transmission.
Coordinate Expression and Trans Presentation of Interleukin (IL)-15Rα and IL-15 Supports Natural Killer Cell and Memory CD8+ T Cell Homeostasis
Authors: Burkett Patrick R. , Koka Rima , Chien Marcia , Chai Sophia , Boone David L. , Ma Averil
Published: September 2004

The high affinity interleukin (IL)-15 receptor, IL-15Rα, is essential for supporting lymphoid homeostasis. To assess whether IL-15Rα's role in vivo is to trans present IL-15, we generated mixed bone marrow chimera from IL-15Rα– and IL-2/15Rβ–deficient mice. We find that IL-15Rα–competent, IL-2/15Rβ–deficient cells are able to support IL-15Rα–deficient natural killer (NK) and memory CD8+ T cells, thus ruling out secondary signals on these cells and demonstrating that IL-15Rα–mediated presentation of IL-15 in trans is the primary mechanism by which IL-15Rα functions in vivo. Surprisingly, using IL-15– and IL-15Rα–deficient mixed chimera, we also find that IL-15 and IL-15Rα must be expressed by the same cells to present IL-15 in trans, indicating that IL-15Rα is required on a cellular level for the elaboration of IL-15. These studies indicate that IL-15Rα defines homeostatic niches for NK and memory CD8+ T cells by controlling both the production and the presentation of IL-15 in trans to NK and CD8+ memory T cells.
Auditory Brainstem Response versus Magnetic Resonance Imaging for the Evaluation of Asymmetric Sensorineural Hearing Loss
Authors: Cueva Roberto A.
Published: September 2004

Objectives/Hypothesis: Auditory brainstem response (ABR) testing and magnetic resonance imaging (MRI) are compared for the evaluation of patients with asymmetric sensorineural hearing loss (SNHL). MRI with gadolinium administration is the current gold standard for identifying retrocochlear lesions causing asymmetric SNHL. The study seeks to determine the sensitivity and specificity of ABR in screening for possible retrocochlear pathology. Most important among SNHL etiologies are neoplastic lesions such as vestibular schwannomas, cerebellopontine angle (CPA) tumors, as well as multiple sclerosis, stroke, or other rare nonneoplastic causes. The study results will allow the author to recommend a screening algorithm for patients with asymmetric SNHL.

Study Design: The study is a multi‐institutional, institutional review board approved, prospective, nonrandomized comparison of ABR and MRI for the evaluation of patients with asymmetric SNHL.

Methods: Three hundred twelve patients (between the ages of 18 and 87) with asymmetric SNHL completed the study. Asymmetric SNHL was defined as 15 dB or greater asymmetry in two or more frequencies or 15% or more asymmetry in speech discrimination scores (SDS). These patients prospectively underwent both ABR and MRI. The ABR and MRI were interpreted independently in a blinded fashion. In addition to the ABR and MRI results, a variety of clinical and demographic data were collected.

Results: Thirty‐one (9.94%) patients of the study population of 312 were found on MRI to have lesions causing their SNHL. Of the 31 patients with causative lesions on MRI there were 24 vestibular schwannomas, 2 glomus jugulare tumors, 2 ectatic basilar arteries with brainstem compression, 1 petrous apex cholesterol granuloma, 1 case of possible demyelinating disease, and 1 parietal lobe mass. Twenty‐two of the 31 patients had abnormal ABRs, whereas 9 patients (7 with small vestibular schwannomas) had normal ABRs. This gives an overall false‐negative rate for ABR of 29%. The false‐positive rate was found to be 76.84%. Sensitivity of ABR as a screening test was 71%, and specificity was 74%.

Conclusions: Ten percent of patients with asymmetric SNHL (by this study's criteria) are likely to have causative lesions found on MRI. Although the recently reported annual incidence of vestibular schwannoma in the general population is 0.00124%, for patients with asymmetric SNHL in this study, the incidence was 7.7% (nearly 4 orders of magnitude higher). ABR has been demonstrated to have low sensitivity and specificity in the evaluation of these patients and cannot be relied on as a screening test for patients with asymmetric SNHL. Keeping the use of MRI conditional on the results of ABR will annually result in missed or delayed diagnosis of causative lesions in 29 patients per 1,000 screened. The author recommends abandoning ABR as a screening test for asymmetric SNHL and adoption of a focused MRI protocol as the screening test of choice (within certain guidelines).
Factors Predicting Patient Perception of Dysphonia Caused by Benign Vocal Fold Lesions
Authors: Behrman Alison , Sulica Lucian , He Tina
Published: September 2004

Objectives/Hypothesis: To assess factors that may be predictive of patient perception of dysphonia severity, as quantified by the Voice Handicap Index (VHI) score. We hypothesize that 1) level of vocal demand; 2) auditory‐perceptual evaluation of dysphonia severity; and 3) vocal function, as defined by phonatory glottal closure and mucosal wave vibration, are the most significant predictors of VHI score.

Study Design: Retrospective review of 100 patients with benign vocal fold lesions.

Methods: Variables assessed for predictive value to VHI score are level of vocal demands, auditory‐perceptual evaluation of dysphonia severity, integrity of mucosal wave vibration and phonatory glottal closure, lesion type, duration of current complaint, smoking, age, and sex. Harmonic to noise ratio was assessed in a subset of 50 patients.

Results: Patients with routine voice use had significantly lower VHI scores than those with more intensive (nonsinging/acting) vocal demands. Patients who quit smoking had greater VHI scores than those who currently smoke or never started. Patients with long‐standing dysphonia tended to have lower VHI scores than those with shorter duration vocal complaints. Auditory‐perceptual assessment of dysphonia severity and harmonic to noise ratio were weak predictors of VHI score. Age, sex, lesion type, phonatory glottal closure, and mucosal wave vibration were not significant predictors of VHI score.

Conclusions: Patient perception of dysphonia severity is independent of many factors commonly assessed during the evaluation of voice disorders. It appears to be an important independent element in the assessment of the effect of a benign vocal fold lesion and critical to therapeutic decision‐making.
Diagnosis of Pneumonia With an Electronic Nose: Correlation of Vapor Signature With Chest Computed Tomography Scan Findings
Authors: Hockstein Neil G. , Thaler Erica R. , Torigian Drew , Miller Wallace T. , Deffenderfer Olivia , Hanson C William
Published: September 2004

Objectives/Hypothesis: The electronic nose is a sensor of volatile molecules that is useful in the analysis of expired gases. The device is well suited to testing the breath of patients receiving mechanical ventilation and is a potential diagnostic adjunct that can aid in the detection of patients with ventilator‐associated pneumonia.

Study Design: A prospective study.

Methods: We performed a prospective study of patients receiving mechanical ventilation in a surgical intensive care unit who underwent chest computed tomography (CT) scanning. A single attending radiologist reviewed the chest CT scans, and imaging features were recorded on a standardized form. Within 48 hours of chest CT scan, five sets of exhaled gas were sampled from the expiratory limb of the ventilator circuit. The gases were assayed with a commercially available electronic nose. Both linear and nonlinear analyses were performed to identify correlations between imaging features and the assayed gas signatures.

Results: Twenty‐five patients were identified, 13 of whom were diagnosed with pneumonia by CT scan. Support vector machine analysis was performed in two separate analyses. In the first analysis, in which a training set was identical to a prediction set, the accuracy of prediction results was greater than 91.6%. In the second analysis, in which the training set and the prediction set were different, the accuracy of prediction results was at least 80%, with higher accuracy depending on the specific parameters and models being used.

Conclusion: The electronic nose is a new technology that continues to show promise as a potential diagnostic adjunct in the diagnosis of pneumonia and other infectious diseases.
Temporal Bone Fractures: Traditional Classification and Clinical Relevance
Authors: Ishman Stacey L. , Friedland David R.
Published: September 2004

Objectives/Hypothesis: The objectives were to evaluate the clinical relevance of traditional temporal bone radiographic descriptors and to investigate the efficacy of an alternative fracture classification scheme.

Study Design: Retrospective consecutive case series.

Methods: Charts and computed tomography scans representing 155 temporal bone fractures at a level I trauma center were reviewed. Fracture types were correlated with clinical presentation and outcomes.

Results: The traditional classification system (i.e., longitudinal, transverse, or mixed) correlated poorly with clinical findings such as facial nerve weakness and cerebrospinal fluid leakage. It also had limited utility in predicting conductive hearing loss and sensorineural hearing. An alternative schema distinguishing petrous from nonpetrous involvement demonstrated better correlation with these measures. Cerebrospinal fluid leak was 1.1 times more common in transverse than in longitudinal fractures but was 9.8 times more common in petrous than in nonpetrous fractures. Similarly, facial nerve injury more strongly correlated with fractures through the petrous temporal bone than did the other fracture types. Sensorineural hearing loss did not correlate with the transverse fracture classification but was significantly more prevalent in petrous fractures. Likewise, conductive hearing loss did not correlate with longitudinal fractures but was four times more common in the “middle ear” subcategory of nonpetrous fractures.

Conclusion: Traditional temporal bone fracture descriptions correlate poorly with clinical findings. However, simply distinguishing petrous from nonpetrous involvement demonstrates significant correlation with the occurrence of serious sequelae of temporal bone fractures. Subcategories of mastoid and middle ear involvement further refine this classification schema to correlate with minor complications. This simple, radiographically based scheme better focuses clinical resources and attention toward more likely sequelae.
Central Effects of Residual Hearing: Implications for Choice of Ear for Cochlear Implantation
Authors: Francis Howard W. , Yeagle Jennifer D. , Brightwell Toni , Venick Holly
Published: September 2004

Objectives/Hypothesis: The study tested the hypothesis that among patients with similar levels of residual hearing in the nonimplanted ear, speech perception outcome is the same whether or not the implanted ear has profound or severe levels of hearing loss.

Study Design: Retrospective.

Methods: Levels of hearing loss in postlingually deafened adults who had cochlear implantation at Johns Hopkins University (Baltimore, MD) between 1991 and 2002 were classified according to pure‐tone averages as bilateral severe (n = 20), severe‐profound (severe in one ear and profound in the other) (n = 23), and bilateral profound (n = 43). There was no significant difference in the age at onset and duration of deafness among the three patient groups. Individuals in the bilateral severe and severe‐profound groups had comparable levels of severe hearing loss in their nonimplanted ears, whereas those in severe‐profound and bilateral profound groups had comparable levels of profound hearing loss in their implanted ears. Speech perception performance was evaluated using words from the Consonant Nucleus Consonant word list, Hearing in Noise Test sentences in quiet, and Central Institute for the Deaf sentences through recorded presentation at 70 dB sound pressure level (SPL).

Results: Despite the profound hearing loss of the implanted ear in the asymmetrical group, there was no significant difference in mean speech perception scores compared with the bilateral severe group within the first year after implant surgery. By comparison, the bilateral profound group had lower speech perception results compared with patients with residual hearing in one or both ears.

Conclusion: The study results suggest that implantation of the profoundly deafened ear does not diminish the functional advantage conferred by residual hearing in a patient with asymmetrical hearing loss. Therefore, the central auditory pathway may be the site at which persistent auditory function has its most beneficial effects.
A Study on the Frequency of Olfactory Dysfunction
Authors: Landis B N. , Konnerth C G. , Hummel T
Published: September 2004

Objectives/Hypothesis: Goals of the study were to evaluate the frequency of olfactory dysfunction in a large representative population without sinonasal complaints and to investigate the extent to which general pathological conditions, medications, and aging influence olfaction.

Study Design: Prospective.

Methods: Results based on an odor identification test (“Sniffin' Sticks”) were reported from 1240 subjects. The subjects presented themselves to an otorhinolaryngology outpatient clinic with relatively mild and transitory complaints unrelated to the upper airways. A detailed otorhinolaryngological examination in combination with a standardized interview further ascertained that these patients had no rhinological problems or symptoms relating to sinonasal disease.

Results: Apart from the confirmation of the effects of age, gender, and certain otorhinolaryngological diseases on the sense of smell, the study results revealed that certain general diseases (liver diseases, nonotolaryngological cancers) appear to influence olfactory function, whereas other diseases or disorders have little or no impact on olfaction (hypertension, cardiovascular problems).

Conclusion: The data in the study revealed that olfactory dysfunction among subjects under 65 years of age is more frequent than previously reported.
Bag‐1 Expression as a Prognostic Factor in Tongue Squamous Cell Carcinomas
Authors: Xie Xin , Clausen Ole Petter F. , Boysen Morten
Published: September 2004

Objectives: To investigate the prognostic significance of the antiapoptotic protein Bag‐1. In addition, the relationship between Bag‐1 expression, other apoptosis‐related and proliferative parameters.

Study Design: Eighty‐five randomly selected patients with T1 to T4 oral tongue squamous cell carcinomas (SCC) were studied.

Methods: Sections from diagnostic, formalin‐fixed, paraffin‐embedded specimens were stained immunohistochemically to detect Bag‐1 protein.

Results: Bag‐1 expression correlated positively with apoptosis‐related parameters such as Bcl‐2 expression (P = .001) and proliferation‐related parameters including Ki‐67, mean argyrophilic nucleolar organizer regions (mAgNOR), and the percentage of AgNOR (pAgNOR) (P = .0117, P = .0257, and P = .0008, respectively). Correlation with Bag‐1 expression and T classification (P = .0362), N classification (P = .0284), and clinical stage (P = .0117) was also found. In addition, Bag‐1 expression was associated with the carbohydrate epitopes H‐antigen and Ley (P = .0004 and P = .0011, respectively). No correlation was found between Bag‐1 expression and p53 accumulation, Bax expression, or apoptotic index (AI). However, a combined score of Bcl‐2 and Bag‐1 expression was inversely associated with AI (P = .046). Patients with tumors expressing high Bag‐1 values had a shortened disease‐specific survival time when compared with those with low Bag‐1 values (P = .0017). A two‐parameter combination between Bag‐1 expression and Bax expression or AI, respectively, revealed an enhanced prognostic potential (P < .0001) when compared with single parameters.

Conclusion: Correlation between Bag‐1 expression and other biologic variables revealed that Bag‐1 might be involved in several biologic processes including apoptosis and cell proliferation. The expression of Bag‐1 protein, particularly in combination with Bax expression or AI, respectively, has prognostic value in oral tongue SCC.
Immunoglobulin E to Staphylococcal and Streptococcal Toxins in Patients with Chronic Sinusitis/Nasal Polyposis
Authors: Tripathi Anju , Conley David B. , Grammer Leslie C. , Ditto Anne M. , Lowery Margaret M. , Seiberling Kristen A. , Yarnold Paul A. , Zeifer Barbara , Kern Robert C.
Published: September 2004

Background: The role of infectious agents and their contribution to the inflammation in chronic sinusitis/nasal polyposis (CS/NP) is not clear. Staphylococcal and streptococcal toxins have superantigen activity and have been implicated in inflammatory conditions such as atopic dermatitis, psoriasis, and asthma.

Objective: We investigated the presence of immunoglobulin (Ig)E antibodies to staphylococcal and streptococcal toxins in the serum of individuals with CS/NP.

Method: IgE antibodies to staphylococcal exotoxins, A, B, and toxic shock syndrome toxin‐1 and streptococcal pyrogenic exotoxin A, B, and C were measured in 23 individuals with CS/NP before functional endoscopic sinus surgery and in controls (7 atopic and 6 nonatopic) individuals without chronic sinusitis. Presence of IgE to the toxins was also correlated with disease severity on sinus computed tomography (CT) scans.

Results: Staphylococcal and streptococcal toxin specific IgE antibodies were detected in 18 of 23 (78%) and 7 of 21 (33.3%) patients, respectively. None of the controls had IgE to the staphylococcal or streptococcal toxins (P < .0001). There was no association between radiographic severity of sinus disease and the presence of IgE antibody to the toxins.

Conclusion: A significantly greater proportion of CS/NP patients had IgE to staphylococcal or streptococcal toxins. Evidence of IgE antibodies directed against staphylococcal and streptococcal toxins in the sera of patients with CS/NP suggests a potential role of these toxins with established superantigen effects in the pathogenesis of CS/NP.