bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of the vertical humidity distribution in the chemistry‐transport model MATCH through increased evaporation of convective precipitation
Authors: Lang Rüdiger , Lawrence M. G.
Published: September 2005

We compare the vertical monthly mean distributions of model water vapor from the Model of Atmospheric Transport and Chemistry (MATCH) to tropospheric in situ sonde profiles and to upper tropospheric water vapor climatologies from the Microwave Limb Sounder (MLS). We perform two model runs with and without increased evaporation of precipitation in midlevel downdrafts and subsidence regions of convective systems. We demonstrate that higher evaporation rates significantly improve the modelled vertical distribution of specific and relative humidity with respect to what has been observed, by moistening of mid and lower tropospheric levels in regions of strong convection. We further demonstrate that the more efficient evaporation increases the modelled water vapor residence time, reducing the gap to observed mean water‐vapor residence times from synergistic use of the Global Ozone Monitoring Experiment (GOME) water‐vapor fields and data from the Global Precipitation Climatology Project (GPCP).
Dominant processes controlling water chemistry of the Pecos River in American southwest
Authors: Yuan Fasong , Miyamoto Seiichi
Published: September 2005

Here we show an analysis of river flow and water chemistry data from eleven gauging stations along the Pecos River in eastern New Mexico and western Texas, with time spanning 1959–2002. Analysis of spatial relationship between the long‐term average flow and total dissolved solids (TDS) concentration allows us to illuminate four major processes controlling river chemistry, namely saline water addition, evaporative concentration with salt gain or loss, dilution with salt gain or loss, and salt storage. Of the 10 river reaches studied, six reaches exhibit the process dominated by evaporative concentration or freshwater dilution with little change in salt load. Four reaches show considerable salt gains or losses that are induced by surface‐ground water interactions. This analysis suggests that the evaporative concentration and freshwater dilution are the prevailing mechanisms, but local processes (e.g., variations in hydrologic flowpath and lithologic formation) also play an important role in regulating the hydrochemistry of the Pecos River.
Simulated 21st century changes in regional water balance of the Great Lakes region and links to changes in global temperature and poleward moisture transport
Authors: Kutzbach John E. , Williams John W. , Vavrus Stephen J.
Published: September 2005

Simulations from eight climate models and two greenhouse gas emission scenarios are used to investigate changes in the hydrologic budget of the Great Lakes region of North America and the links to large‐scale hemispheric/global changes. The ensemble average simulations indicate that increased net moisture (increased P‐E) for the Great Lakes area is associated with a general increase in poleward moisture transport, which in turn is highly correlated with the sensitivity of each climate model to greenhouse‐gas induced warming as measured by the global average increase of temperature.
Tracing geomagnetic conjugate points using exceptionally similar synchronous auroras
Authors: Sato Natsuo , Kadokura Akira , Ebihara Yusuke , Deguchi Hiroki , Saemundsson Thorsteinn
Published: September 2005

We report on highly similar auroras that were simultaneously acquired with all‐sky TV cameras situated at two geomagnetically conjugate points, at Tjornes in Iceland and at Syowa Station in Antarctica. During this event, meso‐scale discrete auroras, including both east‐west and north‐south directed auroral forms, showed excellent similarity in terms of shapes, movements and luminosity variations at both observatories. Using these data we were able to trace the temporal movements and displacement of auroras in the Northern and Southern Hemispheres with a high spatial‐temporal resolution. Our results indicate that the geomagnetic conjugate point of one station moved ∼200 km in longitude and ∼50 km in latitude in one hour due to changes in topology of the geomagnetic field. Similar and dissimilar auroras appeared simultaneously in adjoining areas of sky in both hemispheres.
Spatiotemporal evolution of a transient slip event on the San Andreas fault near Parkfield, California
Authors: Murray J. R. , Segall P.
Published: September 2005

In 1993 several baselines of the two‐color electronic distance meter (EDM) network at Parkfield, California, deviated from their long‐term rates, coincident with anomalous observations from nearby strain meters and a creep meter, as well as an increase in microseismicity. Between October 1992 and December 1994, three M ∼ 4.5 earthquakes occurred beneath Middle Mountain, near the hypocenter of the 1934 and 1966 Parkfield M6 events. We analyzed the two‐color EDM data using a Kalman‐filtering based technique to image the spatiotemporal evolution of slip on the fault at Parkfield between the mid‐1980s and 2003. This method accounts for localized random walk motion of the geodetic monuments and a prominent seasonal signal that affects many baselines. We find that a slip rate increase occurred between January 1993 and July 1996 on the upper 8 km of the fault near Middle Mountain. The peak estimated slip rate during this time was 49 mm/yr, which exceeds the long‐term geologic rate of ∼35 mm/yr. The slip rate evolution appears episodic, with an initial modest increase after the M4.3 earthquake and a much larger jump following the shallower M4.7 event in December 1994. This temporal correlation between inferred slip and seismicity suggests that the moderate earthquakes triggered the aseismic fault slip. The EDM data cannot resolve whether transient slip propagated across the nucleation zone of the 1934 and 1966 M6 Parkfield earthquakes. However, transient slip and its associated stress release in the hypocentral area of previous Parkfield events is consistent with the nucleation of the 2004 M6 Parkfield earthquake elsewhere on the fault.
Determining long‐term effective groundwater recharge by analyzing vertical soil temperature profiles at meteorological stations
Authors: Cheviron Bruno , Guérin Roger , Tabbagh Alain , Bendjoudi Hocine
Published: September 2005

Vertical water seepage in soils results in convective heat transport that modifies the temperature profiles and their variations with time; consequently, there is a relationship between temperature profile variations with time and the vertical Darcy velocity associated with the seepage. Considering the annual sinusoidal time variation of the temperature at the soil surface, it can be shown that convective heat transport has a significant effect on the amplitude damping with depth and a negligible effect on the phase lag with depth of the temperature time signal. Standard meteorological stations constitute a relatively dense network, and we show that their routinely collected data can be used to determine an average value of the vertical Darcy velocity, uz, representing the effective annual recharge over long time periods (several years). A new procedure for determining uz from these temperature records is presented. First, the layering of the medium is determined by an electrical sounding. Then the thermal properties of each layer are inferred from the phase lag with depth. Finally, uz is calculated from the amplitude damping. After having tested this approach with synthetic data, we used the 1984‐2001 Abbeville (Somme, France) data to determine the average recharge over six 3‐year periods. The results are in good agreement with classical meteorological recharge estimates and show a significant increase in the recharge during the last 3‐year period, consistent with the observed phreatic 2001 flood event. Specific temperature measurements at appropriate depths and time steps could drastically improve the sensitivity of the method.
A new algorithm for predicting triplet-triplet energy-transfer activated complex coordinate in terms of accurate potential-energy surfaces
Authors: Frutos Luis Manuel , Castaño Obis
Published: September 2005

The new algorithm presented here allows, for the first time, the determination of the optimal geometrical distortions that an acceptor molecule in the triplet-triplet energy-transfer process undergoes, as well as the dependence of the activation energy of the process on the triplet energy difference of donor and acceptor molecules. This algorithm makes use of the complete potential-energy surfaces (singlet and triplet states), and contrasts with the first-order approximation already published [L. M. Frutos, O. Castaño, J. L. Andrés, M. Merchán, and A. U. Acuña, J. Chem. Phys. 120, 1208 (2004)] in which an expansion of the potential-energy surfaces was used. This algorithm is gradient based and finds the best trajectory for the acceptor molecule, starting from S0 ground-state equilibrium geometry, to achieve the maximum variation of the singlet-triplet energy gap with the minimum energy of activation on S0. Therefore, the algorithm allows the determination of a “reaction path” for the triplet-triplet energy-transfer processes. Also, the algorithm could also serve eventually to find minimum-energy crossing (singlet-triplet) points on the potential-energy surface, which can play an important role in the intersystem crossing process for the acceptor molecules to recover their initial capacity as acceptors. Also addressed is the misleading use of minimum-energy paths in T1 to describe the energy-transfer process by comparing these results with those obtained using the new algorithm. The implementation of the algorithm is illustrated with different potential-energy surface models and it is discussed in the frame of nonvertical behavior.
Phase control over decaying molecular states in intense laser pulses
Authors: Pegarkov Alexander I.
Published: September 2005

A time-dependent approach to study phase control over molecular photoabsorption, provided by intense laser pulses, is elaborate. The method allows for the decay linewidth of molecular states and frequency bandwidth of the controlling laser field, and can be applied in weak and strong laser fields where the perturbation theory is invalid. It is shown that a frequency mismatch between the fundamental laser wave and its third harmonic can destroy control. For the example of the one-photon versus three-photon control a simple picture of interference from two monochromatic absorption pathways is not enough to explain phase control and one needs to consider a nonlinear temporal interference of multiquantum transitions. In the perturbation-theory limit an elegant generalization of the famous Shapiro-Hepburn-Brumer equation for the one-photon versus three-photon control is derived. Various numerical calculations illustrate the dependence of phase control on molecular linewidth, fundamental laser wavelength, pulse duration, and peak intensity. It is obtained, that the one-photon versus three-photon control is productive if the molecular state populations, individually produced by each laser wave, have beats of approximately the same frequency. The calculations demonstrate that an enough intense optical pulse can suppress molecular decay and may be used in order to keep stable the state population of a decaying molecule for a long time. The available experimental results for the one-photon versus three-photon control over simple and large polyatomic molecules are analyzed and recommendations for the experimental improvement of control are formulated.
Optimization of ultrafast laser generated low-energy ion beams from silicon targets
Authors: Stoian R. , Mermillod-Blondin A. , Bulgakova N. M. , Rosenfeld A. , Hertel I. V. , Spyridaki M. , Koudoumas E. , Tzanetakis P. , Fotakis C.
Published: September 2005

We demonstrate the possibility to manipulate the kinetic properties of ion beams generated by ultrafast laser ablation of silicon. The versatility in regulating the sub-keV ion flux is achieved by implementing adaptive control of the temporal shape of incident laser pulses. Tunable characteristics for the charged beams are obtained using excitation synchronized with the phase-transformation dynamics, exploiting transitions to volatile fluid states with minimal energetic expenses.
Spatial dependence of gain nonlinearities in InGaAs semiconductor optical amplifier
Authors: Gomez-Iglesias Alvaro , Fenn Julia G. , Mazilu Michael , Miller Alan
Published: September 2005

Counter-propagating sub-picosecond pulses are used to monitor gain saturation along the waveguide of an InGaAs superlattice semiconductor optical amplifier at 1550nm wavelength. The functional form of the spatial dependence of gain saturation is found to depend on pulse energy. These observations are interpreted by combining the optical nonlinearities associated with interband carrier dynamics and carrier heating together and their respective time constants. We show that the results are consistent with the predictions of a propagation model. Implications for all-optical switching, particularly in the limit of full saturation across the whole amplifier, are discussed.
Nanopillar transistors exhibiting single-electron quantum effects at room temperature
Authors: Wan Yue-Min , Lin Heng-Tein , Sung Chin-Lung , Hu Shu-Fen
Published: September 2005

A nanoelectronic device consisting of a SiNx∕Si∕SiNx nanopillar and a side electrical gate has been assembled to display single-electron resonance tunneling and Coulomb modulation at 300K. The device features an ultrasmall quantum dot of size ∼10×10×3nm3 and its manufacture is fully silicon processing compatible. We find a simple guideline to derive the gate-dot coupling strength α by comparison of the peak spacing in the current-voltage (I-V) characteristics of Id−Vd and Id−Vg at low voltage. The better-defined quantum cavity enables us to apply a three-dimensional single-particle model to identify the excited quantum states.
Field and temperature dependence of the photocurrent in polymer/fullerene bulk heterojunction solar cells
Authors: Gommans H. H. P. , Kemerink M. , Kramer J. M. , Janssen R. A. J.
Published: September 2005

The photocurrent in polymer/fullerene blends is characterized as a function of bias at temperatures ranging from 125to300K. Assuming a constant generation rate and bimolecular recombination, the results are numerically modeled within the drift-diffusion approximation. Bimolecular recombination is found to be a dominant factor in the field dependence of the photocurrent in the entire measured voltage range. Inclusion of field dependent geminate pair dissociation and recombination via the Onsager expressions gives a much stronger field dependence than experimentally observed. From the temperature dependence of the extracted mobilities, we can simultaneously estimate the broadening of the transporting highest occupied and lowest unoccupied molecular orbital levels.
Pathophysiological role of Toll-like receptor 5 engagement by bacterial flagellin in colonic inflammation
Authors: Rhee Sang Hoon , Im Eunok , Riegler Martin , Kokkotou Efi , O'Brien Michael , Pothoulakis Charalabos
Published: September 2005

Commensal and enteroinvasive microbes in the human gut release bacterial flagellin, a specific microbial ligand of Toll-like receptor 5 (TLR5). However, the pathophysiological role of bacterial flagellin in gastrointestinal inflammation has not been determined. Here we evaluated the role of bacterial flagellin using native human colonic mucosa and the mouse colitis model of dextran sulfate sodium (DSS). We demonstrate that, in intact human colonic mucosa, the flagellin/TLR5 response occurs only after exposure to the basolateral, not the apical, surface, implying a basolaterally polarized TLR5 response in human colonic mucosa. In this context, flagellin exposure to injured colonic mucosa due to DSS administration in mice resulted in a TLR5-associated response evaluated by
in vivo
activation of mitogen-activated protein kinase/extracellular signal-related kinase 1/2 (MEK1/2) and elevated IL-6, TNF-α, and keratinocyte-derived chemokine production, whereas intact colonic mucosa did not respond to flagellin. Moreover, flagellin exposure to injured mouse colon
in vivo
, but not to intact colon, also significantly aggravated colonic inflammation, increased mouse mortality, and enhanced histopathological damage in the colonic mucosa. However, the TLR2-specific agonist, peptidoglycan or lipoteichoic acid, did not cause an inflammatory response in intact or DSS-injured mouse colon. Furthermore, intracolonic flagellin administration in mice causes severe apoptosis in colonic epithelium disrupted by DSS administration. These data suggest that intracolonic flagellin via TLR5 engagement is able to elicit inflammatory responses in disrupted colon, whereas the normal colon is not responsive to bacterial flagellin. These results demonstrate that bacterial flagellin plays an important role in the development and progress of colitis.
Transgenic alteration of Toll immune pathway in the female mosquito
Aedes aegypti
Authors: Bian Guowu , Shin Sang Woon , Cheon Hyang-Mi , Kokoza Vladimir , Raikhel Alexander S.
Published: September 2005

Reverse genetics is a powerful tool for understanding gene functions and their interactions in the mosquito innate immunity. We took the transgenic approach, in combination with the RNA interference (RNAi) technique, to elucidate the role of mosquito REL1, a homolog of
Drosophila
Dorsal, in regulation of Toll immune pathway in the mosquito
Aedes aegypti
. By transforming the mosquitoes with ΔREL1-A or a double-stranded RNA construct of REL1 driven by the female fat body-specific vitellogenin (
Vg
) promoter with the pBac[3xP3-EGFP, afm] vector, we generated two different transgenic mosquito strains, one with overexpressed AaREL1 and the second with AaREL1 knockdown. Both strains had a single copy of the respective transgene, and the expression in both transgenic mosquitoes was highly activated by blood feeding. Vg-ΔREL1-A transgenic mosquitoes activate Toll immune pathway in the fat body by blood feeding. The overexpression of both isoforms, AaREL1-A and AaREL1-B, in Vg-ΔREL1-A transgenic mosquitoes resulted in the concomitant activation of
Aedes
Spätzle1A and Serpin-27A, independent of septic injury. The same phenotype was observed in the mosquitoes with RNAi knockdown of an
Aedes
homolog to
Drosophila
cactus, an IκB inhibitor of
Drosophila
Toll pathway. The effect of the transgenic RNAi knockdown of AaREL1 on mosquito innate immunity was revealed by increased susceptibility to the entomopathogenic fungus
Beauveria bassiana
and the reduced induction of Spz1A and Serpin-27A gene expression after fungal challenge. These results have proven that AaREL1 is a key downstream regulator of Toll immune pathway in the mosquito
A. aegypti
.
How adeno-associated virus Rep78 protein arrests cells completely in S phase
Authors: Berthet Carole , Raj Kenneth , Saudan Philippe , Beard Peter
Published: September 2005

Adeno-associated virus Rep78 protein has antiproliferative effects on cells. It inhibits cell cycle progression, and, in particular, Rep78 induces a complete arrest within S phase, a response rarely seen after cell DNA damage. We examined how Rep78 achieves such an efficient S phase block. Rep78 inhibits Cdc25A activity by a novel means in which binding between the two proteins stabilizes Cdc25A, thus increasing its abundance, while at the same time preventing access to its substrates cyclin-dependent kinase (Cdk) 2 and Cdk1. This effect alone does not induce a complete S phase block. In addition, Rep78, as well as Rep68, produces nicks in the cellular chromatin, inducing a DNA damage response mediated by ataxia telangiectasia mutated (ATM) leading to G
1
and G
2
blocks. Mutational analysis shows that the zinc finger domain and nuclease activity of Rep78 are both required for the S phase block. The results suggest that a true S phase block cannot be achieved through a single pathway, and that adeno-associated virus Rep78 protein arrests cells within S phase by interfering with two pathways that would normally lead to an S phase slow-down.
Eusociality: Origin and consequences
Authors: Wilson Edward O. , Hölldobler Bert
Published: September 2005

In this new assessment of the empirical evidence, an alternative to the standard model is proposed: group selection is the strong binding force in eusocial evolution; individual selection, the strong dissolutive force; and kin selection (narrowly defined), either a weak binding or weak dissolutive force, according to circumstance. Close kinship may be more a consequence of eusociality than a factor promoting its origin. A point of no return to the solitary state exists, as a rule when workers become anatomically differentiated. Eusociality has been rare in evolution, evidently due to the scarcity of environmental pressures adequate to tip the balance among countervailing forces in favor of group selection. Eusociality in ants and termites in the irreversible stage is the key to their ecological dominance and has (at least in ants) shaped some features of internal phylogeny. Their colonies are consistently superior to solitary and preeusocial competitors, due to the altruistic behavior among nestmates and their ability to organize coordinated action by pheromonal communication.
Vitamin B6 biosynthesis in higher plants
Authors: Tambasco-Studart Marina , Titiz Olca , Raschle Thomas , Forster Gabriela , Amrhein Nikolaus , Fitzpatrick Teresa B.
Published: September 2005

Vitamin B6 is an essential metabolite in all organisms. It can act as a coenzyme for numerous metabolic enzymes and has recently been shown to be a potent antioxidant. Plants and microorganisms have a
de novo
biosynthetic pathway for vitamin B6, but animals must obtain it from dietary sources. In
Escherichia coli
, it is known that the vitamin is derived from deoxyxylulose 5-phosphate (an intermediate in the nonmevalonate pathway of isoprenoid biosynthesis) and 4-phosphohydroxy-
l
-threonine. It has been assumed that vitamin B6 is synthesized in the same way in plants, but this hypothesis has never been experimentally proven. Here, we show that, in plants, synthesis of the vitamin takes an entirely different route, which does not involve deoxyxylulose 5-phosphate but instead utilizes intermediates from the pentose phosphate pathway, i.e., ribose 5-phosphate or ribulose 5-phosphate, and from glycolysis, i.e., dihydroxyacetone phosphate or glyceraldehyde 3-phosphate. The revelation is based on the recent discovery that, in bacteria and fungi, a novel pathway is in place that involves two genes (
PDX1
and
PDX2
), neither of which is homologous to any of those involved in the previously doctrined
E. coli
pathway. We demonstrate that
Arabidopsis thaliana
has two functional homologs of
PDX1
and a single homolog of
PDX2
. Furthermore, and contrary to what was inferred previously, we show that the pathway appears to be cytosolic and is not localized to the plastid. Last, we report that the single
PDX2
homolog is essential for plant viability.
The anti-tetanus immune response of neonatal mice is augmented by retinoic acid combined with polyriboinosinic:polyribocytidylic acid
Authors: Ma Yifan , Ross A. Catharine
Published: September 2005

Neonates are highly susceptible to infectious diseases and, in general, respond poorly to conventional vaccines due to immaturity of the immune system. In the present study, we hypothesized that the anti-tetanus toxoid (TT) vaccine response of neonatal mice could be enhanced by retinoic acid (RA), a bioactive retinoid, and polyriboinosinic:polyribocytidylic acid (PIC), an inducer of IFN. Early-life treatments with RA and/or PIC were well tolerated and stimulated both primary anti-TT IgG production in infancy and the memory response in adulthood. TT-specific lymphocyte proliferation and type 1/type 2 cytokine production were also significantly augmented. In addition, RA and PIC modulated the maturation and/or differentiation of neonatal B cells, natural killer (NK)/NKT cells, and antigen-presenting cells. Although RA alone increased the neonatal anti-TT antibody response, it selectively increased anti-TT IgG1 and IL-5, resulting in a skewed type 2 response. PIC, a potent adjuvant in adult mice, elevated neonatal anti-TT IgG as well as all IgG isotypes (IgG1, IgG2a, and IgG2b) and induced TT-specific IFN-γ, an important type 1 cytokine; however, PIC alone failed to benefit the memory response. The combination of RA plus PIC was more potent than either agent alone in elevating primary and secondary anti-TT IgG responses as well as IgG isotypes. Moreover, RA plus PIC increased TT-specific IFN-γ and IL-5, suggesting the combination effectively promoted both type 1 and type 2 responses in neonatal mice. Thus, RA combined with PIC, a nutritional-immunological intervention, seems promising as an adjuvant for early-life vaccination.
Extensive 3′ modification of plant small RNAs is modulated by helper component-proteinase expression
Authors: Ebhardt H. Alexander , Thi Emily P. , Wang Ming-Bo , Unrau Peter J.
Published: September 2005

RNA silencing is an evolutionarily conserved process in eukaryotes that represses gene expression by using 21- to 24-nt guide RNAs to mediate mRNA cleavage or translational inhibition. Plants have two distinct groups of silencing-associated small RNAs (smRNAs): the micro RNAs (miRNAs) and the small interfering RNAs (siRNAs). A recent report by Yu
et al.
[Yu, B., Yang, Z., Li, J., Minakhina, S., Yang, M., Padgett, R. W., Steward, R. & Chen, X. (2005)
Science
307, 932-935] has shown that plant miRNAs are modified at their 3′ termini with a methyl group. Here, we show that a large fraction of all silencing-associated smRNAs in tobacco are modified; this modification occurs on the 2′ hydroxyl of the terminal ribose and significantly reduces the cloning efficiency of these modified smRNAs. Expression of the strong silencing suppressor P1/helper-component proteinase results in a marked decrease in the 3′-terminal modification of viral siRNAs but does not significantly affect the modification of endogenous miRNAs and 24-nt siRNAs. The differential modification mediated by helper-component proteinase expression implies that exogenous and endogenous smRNAs are processed through independent pathways that are isolated by subcellular compartmentalization and/or the association with distinct Dicer complexes. The degree of terminal modification may play an important role in regulating the extent to which primary smRNA signals can be amplified by RNA-dependent RNA polymerases.
Divergent roles of IL-23 and IL-12 in host defense against Klebsiella pneumoniae
Authors: Happel Kyle I. , Dubin Patricia J. , Zheng Mingquan , Ghilardi Nico , Lockhart Christie , Quinton Lee J. , Odden Anthony R. , Shellito Judd E. , Bagby Gregory J. , Nelson Steve , Kolls Jay K.
Published: September 2005

Interleukin (IL)-23 is a heterodimeric cytokine that shares the identical p40 subunit as IL-12 but exhibits a unique p19 subunit similar to IL-12 p35. IL-12/23 p40, interferon γ (IFN-γ), and IL-17 are critical for host defense against Klebsiella pneumoniae. In vitro, K. pneumoniae–pulsed dendritic cell culture supernatants elicit T cell IL-17 production in a IL-23–dependent manner. However, the importance of IL-23 during in vivo pulmonary challenge is unknown. We show that IL-12/23 p40–deficient mice are exquisitely sensitive to intrapulmonary K. pneumoniae inoculation and that IL-23 p19−/−, IL-17R−/−, and IL-12 p35−/− mice also show increased susceptibility to infection. p40−/− mice fail to generate pulmonary IFN-γ, IL-17, or IL-17F responses to infection, whereas p35−/− mice show normal IL-17 and IL-17F induction but reduced IFN-γ. Lung IL-17 and IL-17F production in p19−/− mice was dramatically reduced, and this strain showed substantial mortality from a sublethal dose of bacteria (103 CFU), despite normal IFN-γ induction. Administration of IL-17 restored bacterial control in p19−/− mice and to a lesser degree in p40−/− mice, suggesting an additional host defense requirement for IFN-γ in this strain. Together, these data demonstrate independent requirements for IL-12 and IL-23 in pulmonary host defense against K. pneumoniae, the former of which is required for IFN-γ expression and the latter of which is required for IL-17 production.
Use of AlloDerm in Type I Tympanoplasty: A Comparison with Native Tissue Grafts
Authors: Vos Jeremy Dan , Latev Maria D. , Labadie Robert F. , Cohen Seth M. , Werkhaven Jay A. , Haynes David S.
Published: September 2005

Objectives: AlloDerm, an acellular human dermis allograft, has been shown to be an effective option as a tympanic membrane (TM) graft in animals and humans and has several potential advantages, including eliminating donor site morbidity, reducing operative time, and preserving native tissues for later use. We compared AlloDerm and native tissue grafts in type I tympanoplasty with regard to operative time, graft success rate, and audiologic outcome.

Study Design: A retrospective chart review of tympanoplasties performed at a major tertiary referral hospital over a 31 month period, starting with the first use of AlloDerm for TM grafting at this institution.

Methods: The medical charts of all patients undergoing tympanoplasty were reviewed. Only those patients undergoing type I tympanoplasty without mastoidectomy or ossicular chain reconstruction were included. These 114 patients (25 AlloDerm, 56 fascia reconstruction, and 33 fascia plus cartilage reconstruction) were compared for operative time, success rate of the graft, and change in audiologic outcome.

Results: There was a statistically significant reduction in operative time in the AlloDerm group when controlled for surgeon and choice of approach. All groups showed no statistically significant difference in the success rate of the graft and closure of audiologic air‐bone gap, regardless of graft material used.

Conclusions: AlloDerm is an effective TM graft when used in type I tympanoplasty. It is as effective as native tissues in closing the air‐bone gap on audiogram as well as in graft success rate. AlloDerm may also significantly reduce operative time, depending on the surgeon's technique.
Neck Dissection of Level IIb: Is it Really Necessary?
Authors: Corlette Toby H. , Cole Ian E. , Albsoul Nader , Ayyash Mohammad
Published: September 2005

Objectives: To determine whether resection of level IIb is necessary in elective or therapeutic neck dissections.

Study Design: Prospective case series.

Methods: Level IIb nodes were analyzed for micrometastases as separate specimens in 160 neck dissections on 148 patients with squamous cell carcinoma of the head and neck.

Results: In 106 elective neck dissections (N0 necks) from upper aerodigestive tract (UADT) and skin/parotid squamous carcinoma primaries, level IIb was involved in 4.5% and 33%, respectively. In 54 therapeutic neck dissections (N+ necks) from UADT and skin/parotid squamous carcinoma primaries, level IIb was involved in 25% and 71%, respectively. Apart from skin/parotid squamous carcinoma primaries, level IIb was never involved unless level IIa was also involved.

Conclusions: Level IIb nodes can be left in situ in UADT primary carcinomas in nontonsillar N0 necks without significantly compromising regional clearance of micrometastases.
Long‐term Effects of Micronized Alloderm Injection for Unilateral Vocal Fold Paralysis
Authors: Milstein Claudio F. , Akst Lee M. , Hicks M Douglas , Abelson Tom I. , Strome Marshall
Published: September 2005

Objectives: Micronized Alloderm (Cymetra) is a relatively new product used for vocal fold augmentation. Previous studies evaluating possible long‐term effectiveness of this product have shown mixed results. The objective of this present study is to reassess possible long‐term results of Cymetra injection laryngoplasty in patients with unilateral true vocal fold paralysis.

Study Design: Retrospective review of patients with unilateral true vocal fold paralysis who received Cymetra injection laryngoplasty between March 2001 and March 2004.

Methods: Preoperative voice samples and videostroboscopic findings were compared with the most recently available postoperative data to assess efficacy of the procedure. A panel of voice experts analyzed both vocal and vibratory function in these samples. In addition, pre‐ and postoperative voice‐related quality of life measures and patients' self‐ratings of voice outcomes were compared.

Results: Twenty patients (7 male, 13 female; 14 with left‐sided paralysis, 6 with right‐sided paralysis) were identified in the study population. Cymetra injection was performed an average of 45.1 months after onset of vocal fold paralysis (range –216 months), and average follow‐up postinjection was 11.2 (range –35) months. Comparing pre‐ and postoperative measures, voice quality (P < .0001), glottal closure (P < .0001), and degree of vocal fold bowing (P < .0001) were all improved by injection. Quality of life measures and patients' self‐perceptions of vocal quality were also improved (P < .01). Fifteen (75%) patients showed long‐lasting results. Eight patients showed improvement for more than 12 months after injection.

Conclusion: Cymetra injection laryngoplasty offers improved vocal and vibratory function to patients with unilateral true vocal fold paralysis. The benefits of such medialization may be longer lasting than previously reported, and further long‐term study is warranted.
Prospective Clinical Study on Cochlear Function after Erbium:Yttrium‐Aluminum‐Garnet Laser Stapedotomy
Authors: Keck Tilman , Bürner Harald , Rettinger Gerhard
Published: September 2005

Objective: To assess whether the application of the emitting erbium:yttrium‐aluminum‐garnet (Er:YAG) laser in stapedotomy has negative effects on vestibular and cochlear functions.

Design: Prospective, with 12 to 14 months follow‐up.

Setting: Academic tertiary referral center.

Patients: Twenty‐four patients undergoing stapedotomy (primary surgery) in otosclerosis.

Intervention: All patients underwent Er:YAG laser‐assisted stapedotomy for otosclerosis between January 2000 and June 2002.

Main Outcome Measures: Early (1–3 days after surgery) and late (12–14 months after surgery) postoperative bone‐conduction thresholds and the presence of post‐operative tinnitus and vertigo were analyzed. In addition, the relation between applied laser energy and postoperative bone‐conduction thresholds was calculated.

Results: In 22 patients, unchanged preoperative minus early postoperative pure‐tone bone‐conduction averages at 1, 2, and 4 kHz were observed. In one patient, a slight early deterioration between 10 and 20 dB was seen. In 18 patients, unchanged preoperative minus late postoperative pure‐tone bone‐conduction averages at 1, 2, and 4 kHz were observed. In two patients, a slight late deterioration between 10 and 20 dB was seen. In two patients, a new postoperative tinnitus was observed. No patient suffered from vertigo at the time of second evaluation. No correlation between applied laser energy and both postoperative bone‐conduction thresholds was found.

Conclusions: The Er:YAG laser stapedotomy in otosclerosis is a safe technique. Vestibular and cochlear function is not significantly disturbed after Er:YAG laser stapedotomy.
Clinicopathologic Features, Treatment, and Prognosis of Postirradiation Osteosarcoma in Patients with Nasopharyngeal Cancer
Authors: Wei‐wei Liu , Qiu‐liang Wu , Guo‐hao Wu , Zhi‐hua Chen , Zong‐yuan Zeng
Published: September 2005

Objectives: Postirradiation osteosarcoma (PIOS) arising after radiation of nasopharyngeal cancer (NPC) is rare and seldom reported. In this article, we report its clinicopathologic features, outcome, and prognostic factors.

Study Design: Retrospective cohort study.

Methods: Fifteen patients with NPC were determined to have PIOS after reviewing 426 patients with osteogenic sarcomas. Their clinical records, image and pathologic slides, and follow‐up data after treatment were collected to perform analysis.

Results: The incidence rate of PIOS in NPC was approximately 0.037% (15/40,719), which occupied approximately 3.5% (15/426) among all kinds of osteogenic sarcomas. The latent time of PIOS after irradiation for NPC ranged from 4 to 27 years, with a mean of 13.3 years. The location where PIOS arose included 33.3% (5/15) from maxilla, 46.7% (7/15) from mandible, and 20% (3/15) from a mixture of nasal cavity and paranasal sinuses. Radiologically, soft tissue mass, bone destruction, and tumor new bone formation were the main characteristics. Pathologic subtypes included 53.3% (8/15) of fibroblastic osteosarcoma, 33.3% (5/15) of chondroblastic osteosarcoma, and 13.3% (2/15) of mixed type osteosarcoma. Of 15 patients with PIOS, 12 patients were treated with curative intent, and the remaining 3 patients with palliative intent. For 12 patients who had undertaken ablative surgery, 1 patient had residual tumor, and 6 patients had tumor recurrence. The survival time after treatment for all patients ranged from 7 to 41 months, with a mean of 18 months. Kaplan‐Meier estimates of 1 year and 2 year survival rates were 60% and 24%, respectively. Statistical analysis showed that sex and tumor bone formation are significant prognostic factors.

Conclusions: PIOS in NPC is a highly malignant disease with poorer prognosis than in other sites. Surgery combined with pre‐ and postoperative chemotherapy might be an effective way to improve survival.
Benign Paroxysmal Positional Vertigo: 10‐Year Experience in Treating 592 Patients with Canalith Repositioning Procedure
Authors: Prokopakis Emmanuel P. , Chimona Theognosia , Tsagournisakis Minas , Christodoulou Panagiotis , Hirsch Barry E. , Lachanas Vassilios A. , Helidonis Emmanuel S. , Plaitakis Andreas , Velegrakis George A.
Published: September 2005

Objective: To assess the long‐term efficacy of canalith repositioning procedure (CRP) in the treatment of patients with benign paroxysmal positional vertigo (BPPV).

Background: Alternative theories for the pathophysiology of BPPV have been redefined in the past few years. CRP is considered to be the standard technique for its management. However, long‐term follow‐up results have been minimally reported in the literature.

Patients/Methods: Five hundred ninety‐two patients, 290 (49%) men and 302 (51%) women, were enrolled in this prospective study; their ages ranged from 18 to 84 (mean 59) years. At the time of their first examination, patients reported the duration of symptoms varied from 1 day to 18 months. Inclusion criteria were patient history compatible with BPPV and positive provocative maneuver (either Dix‐Hallpike or Roll test). A variant of Epley and Barbeque maneuver was used. The Epley maneuver was used for posterior and anterior canal involvement, and “Barbeque roll” was used for horizontal canal involvement. Short‐term follow‐up was obtained 48 hours and 7 days after initial treatment, whereas long‐term follow‐up was obtained at repeated 6 month intervals.

Results: The posterior semicircular canal was involved in 521 (88%) patients treated, whereas the horizontal and anterior semicircular canals were involved in 59 (10%) and 12 (2%) patients, respectively. Symptoms subsided immediately in 497 (84%) patients. In 77 (13%) patients, the Dix‐Hallpike maneuver remained positive after 48 hours, and CRP was performed again. Patients' mean follow‐up was 46 months; 544 (92%) of 592 patients treated reported no symptoms of vertigo.

Conclusion: Our data, based on long‐term follow‐up, suggest that CRP remains an efficient and long‐lasting noninvasive treatment for BPPV.
A Quantitative Study of the Medial Surface Dynamics of an In Vivo Canine Vocal Fold during Phonation
Authors: Doellinger Michael , Berry David A. , Berke Gerald S.
Published: September 2005

Objectives/Hypothesis: The purpose of this study was to measure the medial surface dynamics of a canine vocal fold during phonation. In particular, displacements, velocities, accelerations, and relative phase velocities of vocal fold fleshpoints were reported across the entire medial surface. Although the medial surface dynamics have a profound influence on voice production, such data are rare because of the inaccessibility of the vocal folds.

Study Design: Medial surface dynamics were investigated during both normal and fry‐like phonation as a function of innervation to the recurrent laryngeal nerve for conditions of constant glottal airflow.

Methods: An in vivo canine model was used. The larynx was dissected similar to methods described in previous excised hemilarynx experiments. Phonation was induced with artificial airflow and innervation to the recurrent laryngeal nerve. The recordings were obtained using a high‐speed digital imaging system. Three dimensional coordinates were computed for fleshpoints along the entire medial surface. The trajectories of the fleshpoints were preprocessed using the method of Empirical Eigenfunctions.

Results: Although considerable variability existed within the data, in general, the medial‐lateral displacements and vertical displacements of the vocal fold fleshpoints were large compared with anterior‐posterior displacements. For both normal and fry‐like phonation, the largest displacements and velocities were concentrated in the upper medial portion. During normal phonation, the mucosal wave propagated primarily in a vertical direction. Above a certain threshold of subglottal pressure (or stimulation to the recurrent laryngeal nerve), an abrupt transition from chest‐like to fry‐like phonation was observed.

Conclusions: The study reports unique, quantitative data regarding the medial surface dynamics of an in vivo canine vocal fold during phonation, capturing both chest‐like and fry‐like vibration patterns. These data quantify a complex set of dynamics. The mathematical modeling of such complexity is still in its infancy and requires quantitative data of this nature for development, validation, and testing.
Carcinoma of the Oropharynx: Factors Affecting Outcome
Authors: Sundaram Krishnamurthi , Schwartz Jerome , Har‐El Gady , Lucente Frank
Published: September 2005

Objectives/Hypothesis: To assess the value of both patient‐ and tumor‐related factors of oropharyngeal squamous cell carcinoma in predicting patient outcome, with respect to the three primary subsites of the disease. It was hypothesized that the subsite has a significant impact on outcome.

Study Design: Historical cohort study.

Methods: A chart review was conducted of 126 patients diagnosed with squamous cell carcinoma of the oropharynx over a 10‐year period. The oropharynx was divided into the following subsites: 1) base of tongue, 2) tonsil and pillars, and 3) uvula, soft palate, and posterior pharyngeal wall. Patient‐related factors included age and gender. Tumor‐related factors included American Joint Committee on Cancer stage, T stage, N stage, and grade. These factors were compared using the end points of disease‐free survival and treatment response (complete response or partial response/no response).

Results: Tumor‐related factors such as American Joint Committee on Cancer stage (P = .016) and T stage (P = .008) had a significant impact on treatment response. The American Joint Committee on Cancer stage (P = .030) and the T stage (P = .005) were also significant predictors of disease‐free survival. Base‐of‐tongue lesions responded significantly worse to treatment than did tonsil and pillar or uvula, soft palate, and posterior pharyngeal wall lesions (P = .014). The disease‐free survival for base‐of‐tongue cancer was significantly worse than for tonsil and pillar or for uvula, soft palate, and posterior pharyngeal wall cancer (P = .010).

Conclusion: Patient‐related factors such as age and gender were not significant in predicting disease‐specific outcome. Important tumor‐related factors were the American Joint Committee on Cancer stage and the T stage. Among the oropharyngeal subsites, squamous cell carcinoma of the base of tongue was associated with the worst outcome.
Quantitative model of cellulite: three‐dimensional skin surface topography, biophysical characterization, and relationship to human perception*
Authors: Smalls L.K. , Lee C.Y. , Whitestone J. , Kitzmiller W.J. , Wickett R.R. , Visscher M.O.
Published: September 2005

Regional Meeting of the International Society for Bioengineering and the Skin, Orlando, Florida, October 28–30, 2004.

Gynoid lipodystrophy (cellulite) is the irregular, dimpled skin surface of the thighs, abdomen, and buttocks in 85% of post‐adolescent women. The distinctive surface morphology is believed to result when subcutaneous adipose tissue protrudes into the lower reticular dermis, thereby creating irregularities at the surface. The biomechanical properties of epidermal and dermal tissue may also influence severity. Cellulite‐affected thigh sites were measured in 51 females with varying degrees of cellulite, in 11 non‐cellulite controls, and in 10 male controls. A non‐contact high‐resolution three‐dimensional laser surface scanner was used to quantify the skin surface morphology and determine specific roughness values. The scans were evaluated by experts and naїve judges (n = 62). Body composition was evaluated via dual‐energy X‐ray absorptiometry; dermal thickness and the dermal‐subcutaneous junction were evaluated via high‐resolution 3D ultrasound and surface photography under compression. Biomechanical properties were also measured. The roughness parameters Svm (mean depth of the lowest valleys) and Sdr (ratio between the roughness surface area and the area of the xy plane) were highly correlated to the expert image grades and, therefore, designated as the quantitative measures of cellulite severity. The strength of the correlations among naїve grades, expert grades, and roughness values confirmed that the data quantitatively evaluate the human perception of cellulite. Cellulite severity was correlated to BMI, thigh circumference, percent thigh fat, architecture of the dermal‐subcutaneous border (ultrasound surface area, red‐band SD from compressed images), compliance, and stiffness (negative correlation). Cellulite severity was predicted by the percent fat and the area of the dermal‐subcutaneous border. The biomechanical properties did not significantly contribute to the prediction. Comparison of the parameters for females and males further suggest that percent thigh fat and surface area roughness deviation are the distinguishing features of cellulite.
Reaction characteristics of a tooth‐bleaching agent containing H2O2 and NaF: in vitro study of crystal structure change in treated hydroxyapatite and chemical states of incorporated fluorine
Authors: Tanizawa Y.
Published: September 2005

This in vitro study was performed to elucidate the reaction mechanism of sodium fluoride (NaF), which is added to tooth‐bleaching agents to lessen the adverse effect of hydrogen peroxide (H2O2) on teeth. Both hydroxyapatite (HAP) and dihydrated dicalcium phosphate (DCPD), model substances for dental hard tissues, dissolved easily in a simple H2O2 solution. In the H2O2/NaF solutions, however, fluorine compounds that could not be identified by X‐ray diffraction (XRD) due to the smallness of the products were formed on the surface of the HAP. X‐ray photoelectron spectroscopy (XPS) studies demonstrated that fluoridated hydroxyapatite (FHAP) was formed on HAP, and that calcium fluoride (CaF2) formation was accelerated by increasing the concentrations of fluorine and H2O2 along with the partial dissolution of HAP. In H2O2/NaF solution, DCPD also transformed easily to FHAP and CaF2, which are favorable to the remineralization process on the tooth surface. Thus, the mechanism of NaF was elucidated, and its use together with H2O2 for tooth bleaching was proved to be effective. Methodologically, the XPS two‐dimensional plot made it possible for the first time to directly estimate the ratio of FHAP and CaF2 in the reaction products, in contrast to the conventional wet‐analytical method, which is simply based on the difference in solubility of the two components.