bluuebunny/crossref_metadata_2025 huggingface dataset:
Anterior approaches in juvenile nasopharyngeal angiofibromas with intracranial extension
Authors: Danesi Giovanni , Panizza Benedict , Mazzoni Antonio , Calabrese Vincenzo
Published: November 2005

Although surgery is regarded as the mainstay of treatment for juvenile nasopharyngeal angiofibromas (JNAs), ancillary treatment modalities such as radiotherapy and on rare occasions chemotherapy are still recommended by many for intracranial extension with apparent radiologic involvement of the cavernous sinus and internal carotid artery. Further, most authors undertaking surgical excision of this subgroup of patients would recommend a lateral or combined frontal and lateral approach for its removal. In a series of 49 cases of JNA, 14 were found during surgery to have intracranial extradural extension; the anterior approach was used for their removal. Although in these cases, on radiography the cavernous sinus often looked to be invaded and the internal carotid artery was displaced superolaterally, there was no difficulty in establishing a plane of dissection. Total removal was achieved in 11 of the 14 cases with a single‐stage procedure. Of the 3 cases with residual tumor, only 1 occurred intracranially. Removal was achieved by a subtemporal approach in this case. For the extracranial residual tumors 1 required a midface degloving and the other, with a 1‐cm residual tumor in the nasopharynx, has been treated conservatively for 6 years with no evidence of growth. No deaths or significant complications have occurred, and radiotherapy has not been required. We conclude that JNAs are tumors with a predilection for spread but that rarely invade dura, acting instead to displace it. We believe that surgery is the method of choice for treating these lesions and that an anterior surgical approach with microsurgical techniques should be used in the first instance. In the last 2 cases we preferred a midface degloving technique to avoid facial scarring and because this approach allows a widening of the surgical field if needed by the performance of bilateral maxillary free bone flaps. On the rare occasion that a lateral approach, with its attendant permanent conductive hearing loss, is found to be necessary for total tumor removal, this can be done as a staged procedure. This may be necessary when the tumor has spread lateral to the horizontal internal carotid artery.
Usefulness of the C1 transverse process as a reference guide in the dissection of the upper lateral neck
Authors: Sheen Tzung‐Shiahn , Yen K. Lawrence , Ko Jenq‐Yuh , Hsu Mow‐Ming
Published: November 2005

In this investigation we dissected 3 cadavers with the lateral cervical approach to assess the usefulness of the transverse process of the atlas (TPA) as a reference guide in the upper lateral neck. Our results indicate that all the important structures in this space can be identified systematically. Lateral to the TPA sits the posterior belly of the digastric muscle, the stylohyoid muscle, and the occipital artery. Anterior to the TPA, the styloid process can be exposed. The internal jugular vein and cranial nerves X, XI, and XII sit between the styloid process and the TPA. Superior to the TPA, tracing the carotid sheath upward, the carotid canal and jugular foramen can be reached. Anteroinferior to the jugular foramen, the hypoglos‐sal nerve emerges from the cranial cavity through the hypoglossal canal. Posterior to the TPA, the sub‐occipital triangle can be recognized. Within the triangle, the vertebral artery and its accompanying venous complex can be identified.
Use of [18F]‐fluorodeoxyglucose positron emission tomography in monitoring response of recurrent neurotropic desmoplastic melanoma to radiotherapy
Authors: Hannah Anthony , Feigen Malcolm , Quong George , Akhurst TIM , Berlangieri Salvatore U. , Zimet Allan , Zalcberg John , Mckay W. J. , Scott Andrew M.
Published: November 2005

A 35‐year‐old man originally sought treatment in 1985 for an ulcerating lesion on the lower lip. When the lesion was resected, histology showed an amelanotic neurotropic variant of desmoplastic melanoma invading deep into the muscle of the lip around small nerves and blood vessels; staining was positive for S‐100 protein. Repeat excisions were performed twice during the next 2 months, before histologically complete removal was attained.
Auditory‐Nerve Integrity after Middle‐Fossa Acoustic‐Tumor Removal
Authors: Friedman Rick A. , Brackmann Derald E. , Mills Dawna
Published: November 2005

We sought to investigate the functional integrity of the auditory nerve in patients with postoperative hearing loss after middle cranial fossa acoustic‐tumor removal in a case‐series descriptive study. The study setting was a tertiary referral center, a private otologic practice. The study population comprised seven patients who underwent a middle‐cranial‐fossa approach for unilateral acoustic‐tumor resection and sustained postoperative anacusis with an anatomically intact auditory nerve. Four were men and three women; they ranged in age from 30 to 60 years; all underwent surgery between 1990 and 1994 and agreed to return to the center to participate in the study during 1995. Diagnostic electrical promontory stimulation was used to determine the functional integrity of the auditory nerve. Our main outcome measures were the presence or absence of discrete tone perception, electrical threshold, maximum acceptable level and dynamic range, gap detection and temporal difference limen during electrical promontory stimulation. Three of the seven patients demonstrated positive responses to electrical promontory testing (e.g., discrete tone perception). All three were able to perform the gap‐detection and temporal difference limen tests. None of the pre‐operative characteristics was related to performance on promontory stimulation testing. We conclude that the middle cranial fossa approach permits anatomic—and, in some cases, functional auditory‐nerve preservation. These data suggest that auditory rehabilitation in some patients who sustain anacusis after the middle cranial fossa approach to acoustic tumors, as in neurofibromatosis 2, may be provided with cochlear implantation.
Inhibition of Cell Proliferation in Head and Neck Squamous Cell Carcinoma Cell Lines with Antisense Cyclin D1
Authors: Wang Marilene B. , Billings Kathleen R. , Venkatesan Natarajan , Hall Frederick L. , Srivatsan Eri S.
Published: November 2005

Cyclin D1 and cyclin G are essential regulatory factors in the progression of the cell cycle from G0 through G1 and S phase. Aberrations in expression of these cyclins may lead to dysregulated cellular proliferation that could result in neoplasia. Amplification and overexpression of cyclin D1 have been observed in many human cancers, whereas cyclin G is a new cyclin recently described in osteosarcoma cells. This study was performed to determine whether these cyclins were amplified in head and neck squamous cell carcinoma (HNSCC) tumors. Polymerase chain reaction of DNA extracted from 22 HNSCC primary tumors and three HNSCC cell lines did not reveal amplification of cyclin D1 in any of the tumor samples. Southern blot analysis identified amplification of cyclin D1 in a single tumor. Amplification of cyclin G was not observed in any of the tumors by Southern blot hybridization with a cyclin G probe. HNSCC cell lines transfected with antisense cyclin D1 were tested for cell proliferation by the incorporation of 3H‐thymidine into cells grown in serum‐free media. By 72 hours of incubation, there was a greater than 30% reduction in proliferation of cells transfected with antisense cyclin D1 as compared with non‐transfected control cells. The results indicate that cyclin D1 may play an important role in the growth and proliferation of HNSCC cells.
Influence of Computed Tomography on Pretherapeutic Tumor Staging in Head and Neck Cancer Patients
Authors: Prehn Robert B. , Pasic Thomas R. , Harari Paul M. , Brown W. Douglas , Ford Charles N.
Published: November 2005

Refinements in radiographic techniques have resulted in increased use of radiographic studies in the evaluation of patients with head and neck cancer over the past 20 years. To assess the impact of such studies, we compared tumor clinical stages based solely on physical‐examination findings with those obtained with the addition of CT findings. This study was accomplished through case review of 81 head and neck cancer patients who underwent CT after preliminary TNM‐stage assignment as determined on the basis of physical examination alone. In this cohort, 44 patients (54%) had a change in assigned clinical stage. We reviewed individual anatomic sites to determine where CT was found to be most useful in modifying tumor stage. Changes in tumor and nodal stage were found across all major sites of the head and neck. Tumors of the hypopharynx were the most likely to change stage (90%) on the basis of CT findings, whereas tumors of the glottic larynx were least likely to undergo a change in stage (16%). The therapeutic implications of these findings are discussed in the context of the published literature.
Sucralfate for Posttonsillectomy Analgesia
Authors: Özcan Müge , Altuntasl Ali , Ünal Adnan , Nalcla Yildirim , Aslan Asim
Published: November 2005

Pain is one of the most troublesome complications of tonsillectomy. The pain appears as throat pain, otalgia, or both, and continues until mucosal recovery on the tonsillar fossae is complete. Some surgical and hemostasis techniques may increase pain. Analgesics, antibiotics, steroids, and local and topical anesthetics are used to relieve posttonsillectomy pain, but none has the desired effectiveness. The pain reliever must not increase bleeding and must have minimal side effects. Sucralfate, a basic amino salt of sucrose octasulfate, binds to the matrix protein of a peptic ulcer and produces a protective barrier. Tonsillectomy leaves two large ulcerous wounds, and sucralfate may bind those wounds as it does peptic ulcers. In this controlled study, the efficacy of sucralfate on posttonsillectomy throat pain, otalgia, analgesic requirement, degree of strength, bleeding, body temperature, and mucosal recovery is investigated in 80 patients. Sucralfate is found to significantly reduce throat pain and analgesic requirement after surgery.
Age‐ and gender‐related elastin distribution changes in human vocal folds
Authors: Hammond Thomas H. , Gray Steven D. , Butler John , Zhou Ruixia , Hammond Elizabeth
Published: November 2005

The composition of the lamina propria in human vocal folds has been shown to affect vocal performance. Elastin plays a significant role in the biomechanical effects of the lamina propria. We obtained 19 larynges from the state medical examiner from subjects whose cause of death was unrelated to the trachea and laryngeal regions. The sample contained male and female subjects in the infant, adult, and geriatric age groups. We stained the vocal folds for elastin with Verhoeff's elastic tissue stain and studied them with use of an image analysis system configured for light microscopy. Distributions of elastin were measured from superficial to deep within the lamina propria (from epithelium to vocal muscle). These elastin distributions were then compared with the use of statistical software. The data showed that there was an increase in elastin content from the infant through geriatric stages. No gender‐related differences were found. Infant folds had about 23% of the elastin found in adults, and geriatric subjects had about 879% of the elastin found in adults. Both of these results were statistically significant (p < 0.05). The distributions were consistent with previous observations that the lamina propria is a layered structure with most of the elastin present in the intermediate layer. This layer was larger in geriatric subjects than in adult and pediatric subjects. We observed that the fiber diameter appeared to be larger in geriatric subjects (this observation is currently being verified with electron microscopy) whereas smaller, spiraled fibers appeared in pediatric subjects.
Endoscopic sinus surgery with magnetic resonance imaging guidance: Initial patient experience
Authors: Fried Marvin P. , Topulos George , Hsu Liangge , Jalahej Heyam , Gopal Harsha , Lauretano Arthur , Morrison Paul R. , Jolesz Ferenc A.
Published: November 2005

We report the first endoscopic surgeries performed with patients under general anesthesia using intraoperative guidance with MRI. The procedures were experimental and intended to test (1) the unusual working environment of a unique new “open‐configuration” MRI unit for head and neck surgery, and (2) real‐time image guidance. Twelve patients underwent endoscopic sinus surgery while under general anesthesia in a new open MRI unit that provides the surgeon with access to the patient while imaging is performed. Eleven patients had chronic sinusitis (eight of them had bilateral disease), and one had a right nasoethmoid and antral tumor. All 12 surgeries were performed without complications. Both the endoscopic view and the MRI scans were available at the surgical field. The image plane was surgeon controlled, and the MRI updated images in as little as 14 seconds. MRI provided adequate visualization of both the disease and the related anatomy and allowed the surgeon to navigate during the procedure. The intraoperative data reflect the tissue changes during surgery and provide optimum feedback for surgical guidance. Although the operating environment poses some limitations, it has become apparent that intraoperative MRI has a role in the treatment of head and neck disorders and warrants further study.
Skeletal expansion combined with soft‐tissue reduction in the treatment of obstructive sleep apnea in children: Physiologic results
Authors: Cohen Steven R. , Ross David A. , Burstein Fernando D. , Jean‐Francois Lefaivre , Frcsc John E. , Cathy Simms
Published: November 2005

Twenty consecutive children, ranging in age from 6 days to 18 years, were treated with skeletal expansion, in addition to soft‐tissue reduction, for medically refractory obstructive sleep apnea. The underlying diagnoses were craniofacial microsomia (n = 6), Down syndrome (n = 3), Pierre Robin syndrome (n = 3), cerebral palsy (n = 3), Nager's syndrome (n= 1), Treacher Collins syndrome (n= 1), cri du chat syndrome (n = 1), juvenile rheumatoid arthritis (n= 1), and temporomandibular joint ankylosis (n= 1). Fourteen children had severe medically refractory sleep apnea and were tracheostomy candidates; in the remaining six, tracheostomies were placed shortly after birth and could not be decannulated. Overnight, 12‐channel polysomnography was obtained before and after surgery. The mean apnea index improved from 7.42 to 1.26, the mean respiratory disturbance index improved from 25.24 to 1.72, and the mean lowest apnea‐related oxygen saturation improved from 68% to 88%. Of the 14 children with medically refractory obstructive sleep apnea, two required tracheostomies. Of the six patients with tracheostomies, five have been decannulated at the time of this writing. Skeletal expansion in conjunction with soft‐tissue reduction in the pediatric population permits substantial increases in the volume of both the nasopharynx and oropharynx. Creative use of conventional osteotomies and the application of distraction osteogenesis have enabled surgeons to apply maxillofacial and craniofacial techniques in treating children with obstructive sleep apnea.
An experimental comparison of different kinds of laryngeal muscle reinnervation
Authors: Hongliang Zheng , Shuimiao Zhou , Shicai Chen , Zhaoji Li , Yi Cuan
Published: November 2005

In this study, we attempted to determine which method was the best for reinnervating the laryngeal adductor muscles by comparing nerve suture, nerve implantation, and nerve‐muscular pedicle (NMP) transfer, as well as the length of time that could elapse after denervation and still allow for successful reinnervation with the ansa cervicalis. Reinnervation was performed in 36 dogs, at 6‐, 8‐, 10‐, 12‐ and 18‐month intervals after denervation via the three methods of muscle reinnervation described above. We noted some return of adduction in the cases using nerve suture before a 10‐month interval after denervation, and with nerve implantation and NMP transfer before the 8‐month intervals. The variable adduction was caused by reinnervation of the adductor muscles from the ansa cervicalis, as demonstrated by laryngeal spontaneous and evoked electromyography, the strength of muscle contraction, and histologic findings. Adduction was not observed in the cases after the above‐mentioned intervals but partial improvement of the bulk and strength of the reinnervated vocal cord was still achieved. An analysis of the experimental results showed that nerve suture was superior to nerve implantation and the NMP technique. Little difference was noted between nerve implantation and the NMP technique.
Prevalence and genetic and environmental influences on anxiety disorders in 6-year-old twins
Authors: BOLTON DEREK , ELEY THALIA C. , O'CONNOR THOMAS G. , PERRIN SEAN , RABE-HESKETH SOPHIA , RIJSDIJK FRÜHLING , SMITH PATRICK
Published: November 2005

Background. Prevalence of childhood anxiety disorders at specific ages and genetic etiological influences on anxiety disorders in young children have been little studied. The present study reports prevalence estimates in a community sample of 6-year-old twins, and patterns of genetic and environmental influences on these early-onset anxiety disorders.

Method. Using a two-phase design 4662 twin-pairs were sampled and 854 pairs were assessed in the second phase by maternal-informant diagnostic interview using DSM-IV criteria.

Results. The most common conditions were separation anxiety disorder (SAD) [2·8%, 95% confidence interval (CI) 2·1–3·8, for current disorder] and specific phobia (10·8%, 95% CI 8·4–13·6, for current disorder). Behavioral genetic modeling was feasible for these two conditions, applied to two phenotypes: symptom syndrome (regardless of impairment) and the narrower one of diagnostic status (symptom syndrome with associated impairment). The heritability estimate for SAD diagnostic status was high, 73%, with remaining variance attributed to non-shared environment. The heritability estimates for specific phobia were also high, 80% for the symptom syndrome and 60% for diagnostic status, with remaining variance attributed in both cases to non-shared environment.

Conclusions. Compared with previous epidemiological surveys of children and adolescents in wide age-bands, the current estimates suggest that rates of anxiety disorders assessed in young childhood are generally at least as high and perhaps higher compared with those found in older children. The heritability estimates suggest that the genetic effects on these early-onset anxiety disorders are substantial and more significant than environmental effects, whether shared or non-shared.
Kinematics and workspace analysis of a three-axis parallel manipulator: the Orthoglide
Authors: Pashkevich A. , Chablat D. , Wenger P.
Published: November 2005

The paper addresses kinematic and geometrical aspects of the Orthoglide, a three-DOF parallel mechanism. This machine consists of three fixed linear joints, which are mounted orthogonally, three identical legs and a mobile platform, which moves in the Cartesian x-y-z space with fixed orientation. New solutions to solve inverse/direct kinematics are proposed, and we perform a detailed workspace and singularity analysis, taking into account specific joint limit constraints.
Outbreak of early syphilis in an institution for the care of adults with mental disorders
Authors: VLAJINAC H. , SIPETIC S. , BJEKIC M. , SAVCIC G. , MARINKOVIC J.
Published: November 2005

This paper describes the features of an outbreak of early syphilis in an institution for the care of adults with mental disorders. A case-note review was performed. In the period June to November 2001, 87 cases of syphilis were diagnosed [25 primary, 21 secondary and 41 early latent syphilis in 983 inmates (crude attack rate 8·9%)]. Among them 82 were heterosexual, four were homosexual or bisexual, and for one case sexual preference was not established. About half the cases were known to be promiscuous. The initial case was not identified. Penicillin therapy was administered to all cases and all known or suspected sexual contacts. Sporadic cases of syphilis have, however, continued to emerge from time to time. Institutions for patients with mental disorders are vulnerable to sexually transmitted diseases, and special strategies should be devised for their control.
EDITORIAL Interprofessional education: a review
Authors: Hasan Mujtaba
Published: November 2005

Recent changes in medical education as well as in the organization and delivery of health care in the UK have emphasized the need for doctors, nurses and other health care professionals to learn to work together as teams in order to provide the best possible care for patients. The importance of interprofessional education (IPE) and teamwork is, therefore, being increasingly recognized and given priority in medical education.
The Change of the LMM Auger Spectra in 3d-Metals Due to Oxidation
and Its Correlation with the Change of the Atomic Magnetic Moment
Authors: Zheltysheva Olga R. , Surnin Dmitry V. , Guy Dmitry E. , Gil'mutdinov Faat Z. , Ruts Yuri V. , Grebennikov Vladimir I.
Published: November 2005

The surfaces of crystalline samples of 3d-metals (Mn, Fe, Co, Ni, and
Cu) and their stoichiometric oxides have been studied by Auger
spectroscopy. A correlation between the change in the LVV (L-inner
level-valence-valence electron transition) Auger intensities and the
change of the squares of the corresponding atomic-magnetic moments has
been observed. This is because of the complicated nature of the Auger
process. That is, the Auger electron emission is a result of the inner
atomic level excitation by electron impact and Auger annihilation of the
inner-level hole. Therefore, the Auger process has been considered a
second-order process, and spin polarization of the valence states has been
taken into account for the LMM (L-inner level-M-inner level-M-inner level
electron transition) Auger spectra of 3d-metals.
Electron Microscopy Studies of Potassium Sodium Niobate
Ceramics
Authors: Jenko Darja , Benčan Andreja , Malič Barbara , Holc Janez , Kosec Marija
Published: November 2005

Using electron microscopy,
K0.5Na0.5NbO3 (KNN) ceramics sintered at
1030°C for 8 h and 1100°C for 2 and 24 h was studied. The scanning
electron microscopy and X-ray spectrometry revealed that the materials
consisted of a matrix phase in which the (Na+K)/Nb ratio corresponded
closely to the nominal composition and a small amount of Nb-rich secondary
phase. A bimodal microstructure of cube-shaped grains was revealed in the
fracture and thermally-etched surfaces of the KNN. In the ceramics
sintered at 1100°C, the larger grains (up to 30 μm across),
contained angular trapped pores. The transmission electron microscopy
analysis revealed that the crystal planes of the grains bordering the
intragranular pore faces were of the {100} family with respect to the
simple perovskite cell. Ferroelectric domains were observed in the grains
of this material.
An FTIR study of Pseudomonas aeruginosa PAO1 biofilm development: interpretation of ATR–FTIR data in the 1500–1180 cm−1 region
Authors: Pink J. , Smith-Palmer T. , Chisholm D. , Beveridge T. J. , Pink D. A.
Published: November 2005

Infrared spectra of Pseudomonas aeruginosa PAO1 biofilms grown on 40° ZnSe and 40° AMTIR (amorphous material transmitting infrared radiation, Ge33As12Se55) internal reflection elements (IRE) at 26 °C in a flow cell were collected. The depth of penetration of the evanescent wave was sufficient to identify four biofilm stages during the experiment: (1) cell/substratum attachment, (2) lag phase, (3) later-stage growth, and (4) restructuring (e.g. rearrangement, detachment or “erosion”). Our experimental results provide the first detection via a non-perturbative technique of an excess of protein in the neighbourhood of the surface. Our mathematical analysis applied to the data supports the conclusion that our observations cannot be completely accounted for by the changing characteristics of bacterial proteins but, rather, shows that an accumulation of excess protein near the attachment surface is taking place. On the assumption that biofilm cells are approximately of the same size as those of the planktonic culture, this suggests the presence of extracellular proteins. Our data do not support the presence of extracellular nucleic acids near the attachment surface in these biofilms. This conclusion is based on our observation that, during the initial 20 h of development (stage 2 and the beginning of stage 3), biofilms had a higher proportion of protein to nucleic acid than in the latter part of stage 3 and in stage 4. In the restructuring phase this ratio became equal to the ratio determined for planktonic cultures. The decrease of biomass during stage 4 is inconsistent with the physical removal or sloughing-off of cellular aggregates from biofilms within a few micrometres of the substrate surface but, instead, supports a model of gradual cell migration away from it. During this cell migration there is also a gradual loss of extracellular protein. Alternatively, therefore, the restructuring may involve cell lysis and the observed loss of biomass may be due to soluble macromolecules being removed from the neighbourhood of the surface.
Rapid formation of a sea ice barrier east of Svalbard
Authors: Nghiem S. V. , Van Woert M. L. , Neumann G.
Published: November 2005

Daily SeaWinds scatterometer images acquired by the QuikSCAT satellite show an elongated sea ice feature that formed very rapidly (∼1–2 days) in November 2001 east of Svalbard over the Barents Sea. This sea ice structure, called “the Svalbard sea ice barrier,” spanning approximately 10° in longitude and 2° in latitude, restricts the sea route and poses a significant navigation hazard. The secret of its formation appears to lie in the bottom of the sea: A comparison between bathymetry from the International Bathymetric Chart of the Arctic Ocean data and the pattern of sea ice formation from scatterometer data reveals that the sea ice barrier conforms well with and stretches above a deep elongated channel connecting the Franz Josef–Victoria Trough to the Hinlopen Basin between Svalbard and Franz Josef Land. Historic hydrographic data from this area indicate that this sea channel contains cold Arctic water less than 50 m below the surface. Strong and persistent cold northerly winds force strong heat loss from this shallow surface layer, leading to the rapid formation of the sea ice barrier. Heat transfer rates estimated from European Centre for Medium‐Range Weather Forecasts temperature and wind data over this region suggest that the surface water along the deep channel can be rapidly cooled to the freezing point. Scatterometer results in 1999–2003 show that sea ice forms in this area between October and December. Understanding the ice formation mechanisms helps to select appropriate locations for deployment of buoys measuring wind and air‐sea temperature profile and to facilitate ice monitoring, modeling, and forecasting.
Coupling between suspended sediment distribution and turbulence structure in a laboratory turbidity current
Authors: Baas Jaco H. , McCaffrey William D. , Haughton Peter D. W. , Choux Caroline
Published: November 2005

A detailed laboratory experiment reveals the coupling between flow and suspended sediment properties (velocity, turbulence, concentration, and granulometry) in a low‐density, depositional turbidity current. A model is proposed that explains spatial variation in the coupling through size segregation and mixing controlled by the interplay between upward directed turbulence and gravitational settling of suspended particles. The head of the flow is strongly turbulent, relatively well mixed, dilute, and coarse grained because upward directed turbulence, related to frontal shear and mixing with ambient water, generally outbalances particle settling. The body is grain size and density stratified, with strong turbulence confined to upper and lower flow boundaries. Here settling is generally more important than turbulence. Contrasting dynamics of different particle sizes modify the general patterns recognized in the head and body. Thus preferential settling of the coarsest particles produces normal grading in the lower head. In the lower body, highly turbulent, relatively low downstream velocity fluid packages, interpreted as upward moving, basal shear‐induced ejections, alternate with less turbulent, higher downstream velocity fluid packages. Relatively coarse grains react to these flow changes by alternate vertical mixing and preferential accumulation near the flow's base, whereas the distribution of finer grains remains unaffected. Kelvin‐Helmholtz waves generated by upper boundary shear penetrate the upper body. The zone of maximum flow velocity is typically weakly turbulent and appears to form a barrier to turbulence‐induced particle exchange between the lower and upper flow regions. The coupling model entails periodic changes in grain size measures near the flow's base, which may explain the formation of lamination and banding in natural turbidites.
Island wakes in the Southern California Bight
Authors: Caldeira R. M. A. , Marchesiello P. , Nezlin N. P. , DiGiacomo P. M. , McWilliams J. C.
Published: November 2005

Wind‐ and current‐induced island wakes were investigated using a multiplatform approach of in situ, remote sensing, and numerical model simulations for the Southern California Bight (SCB). Island wind wakes are a result of sheltering from the wind, with weak wind mixing, strong heat storage, and consequent high sea surface temperature (SST). Wind wakes around Santa Catalina Island are most persistent during spring and summer months. Current wakes, caused by the disruption of the poleward traveling California Countercurrent, induce eddies to form off the north end of Catalina Island, and these move poleward every 9–12 days. Current wake eddies induce strong mixing, with low SST and high‐density sea surface signatures, whereas wind wakes induce high sea surface temperature signatures associated with the formation of a well‐defined shallow thermocline. Current wake eddies vary from 1 to 30 km in diameter. From numerical solutions we predicted the frequency of occurrence of current‐induced wakes off Santa Catalina Island. Wind wakes were also observed off all the other islands of the SCB as seen from the analysis of synthetic aperture radar data. Time series analysis of the island mass effect phenomenon has shown a concurrence of low SST and high sea surface chlorophyll for Santa Catalina, San Nicholas, and San Clemente islands that might be related to the seasonality of the California Current and California Countercurrent. Future oceanographic research in the SCB should not ignore the occurrence of wind‐ and current‐induced island features since they may be important in the transport and/or retention of nutrients, pollutants, and plankton.
Can global warming affect tropical ocean heat transport?
Authors: Hazeleger Wilco
Published: November 2005

Tropical meridional ocean heat transport is studied in six coupled ocean‐atmosphere models in which atmospheric CO2 concentration has been increased. In the Indo‐Pacific, the strength of Subtropical Cells (STCs) changes in response to changes in the trade winds. However, the change is not consistent among models. In contrast, in all models the tropical Indo‐Pacific heat transport remains nearly constant over time due to compensation of STC and the horizontal gyre variations. Even under strong atmospheric radiative forcing the tropical Indo‐Pacific ocean heat transport trends are determined by changes in circulation, rather than changes in the stratification. Ocean heat transport in the tropical Atlantic responds to weakening of the basin‐wide meridional overturning circulation (MOC). The trends in the South Atlantic STC do not affect ocean heat transport.
Amplitude ratios for complete moment tensor retrieval
Authors: Jechumtálová Zuzana , Šílený Jan
Published: November 2005

We generalized the Snoke's method of inversion of amplitude ratios and polarities (P, SH, SV) designed to determine double‐couple earthquake focal mechanism (Snoke, 2003). We search for a general dipole source described by unconstrained seismic moment tensor, i.e. non‐double‐couple (non‐DC) source components are allowed as well. Based on synthetic tests simulating various configurations of seismic stations from sparse to dense networks and from low to high number of stations, conditions for successful inversion were found. We specified minimum amount of data, i.e. number of stations used and amplitude ratios employed, for reliable retrieval of non‐shear source components. We showed that processing of non‐DC data by traditional DC‐constrained algorithm could provide distorted fault‐plane solution. The approach is demonstrated with local data (1st arrival amplitudes) from 1997 West Bohemia, Czechia earthquake swarm and from 2000 injection experiment in KTB, Germany.
On the determination of atmospheric minor gases by the method of vanishing partial derivatives with application to CO2
Authors: Chahine M. , Barnet C. , Olsen E. T. , Chen L. , Maddy E.
Published: November 2005

We present a general method for the determination of minor gases in the troposphere from high spectral resolution observations. In this method, we make use of a general property of the total differential of multi‐variable functions to separate the contributions of each individual minor gas. We have applied this method to derive the mixing ratio of carbon dioxide in the mid‐troposphere using data from the Atmospheric Infrared Sounder (AIRS) currently flying on the NASA Aqua Mission. We compare our results to the aircraft flask CO2 measurements obtained by H. Matsueda et al. over the western Pacific and demonstrate skill in tracking the measured 5 ppmv seasonal variation with an accuracy of 0.43 ± 1.20 ppmv.
Continued deceleration of Whillans Ice Stream, West Antarctica
Authors: Joughin I. , Bindschadler R. A. , King M. A. , Voigt D. , Alley R. B. , Anandakrishnan S. , Horgan H. , Peters L. , Winberry P. , Das S. B. , Catania G.
Published: November 2005

Earlier observations indicated that Whillans Ice Stream slowed from 1973 to 1997. We collected new GPS observations of the ice stream's speed in 2003 and 2004. These data show that the ice stream is continuing to decelerate at rates of about 0.6%/yr2, with faster rates near the grounding line. Our data also indicate that the deceleration extends over the full width of the ice plain. Extrapolation of the deceleration trend suggests the ice stream could stagnate sometime between the middle of the 21st and 22nd Centuries.
Morphology of the equatorial anomaly and equatorial plasma bubbles using image subspace analysis of Global Ultraviolet Imager data
Authors: Henderson S. B. , Swenson C. M. , Christensen A. B. , Paxton L. J.
Published: November 2005

The equatorial anomaly (EA) is host to the highest ionospheric densities on Earth. Disturbances within the EA result in plasma density depletions and large density gradients. This paper presents observations of global quiet time morphology of the EA as measured by images of nighttime ionospheric 135.6 nm radiation taken by the Global Ultraviolet Imager (GUVI) on NASA's Thermosphere, Ionosphere, and Mesosphere, Energetics and Dynamics (TIMED) spacecraft. It also presents equatorial plasma bubble (EPB) morphology as determined by detection of intensity depletions in GUVI images. The technique used for analysis is unique in that it allows for simultaneous characterization of the EA and detection of EPBs. This paper also presents extensive observations of EA and EPB morphology and shows that EA morphology can be well characterized by data taken from the 2030–2130 MLT range. Further, this paper identifies crest symmetry in intensity and latitude as an indicator of both EA and EPB morphology. For all longitudes, the crest‐to‐trough ratio (CTR) is shown to be well correlated with the EPB rate. While the CTR may drop with solar flux, EPB levels do not. Thus the absolute CTR is less an indicator than the change in the CTR as a function of longitude for a given season and solar flux. One significant exception to this correlation is observed in the Pacific sector during the June solstice. In this case the EPB rate is high despite a low CTR.
Geodetic GPS measurements in south Iceland: Strain accumulation and partitioning in a propagating ridge system
Authors: LaFemina P. C. , Dixon T. H. , Malservisi R. , Árnadóttir T. , Sturkell E. , Sigmundsson F. , Einarsson P.
Published: November 2005

GPS observations in south Iceland between 1994 and 2003 are compared with two‐dimensional elastic half‐space and viscoelastic coupling models for two parallel rift zones, representing the Western and Eastern volcanic zones (WVZ, EVZ). GPS data from the Hreppar block, between the WVZ and EVZ, fit a rigid block model within uncertainties. Spreading rates across the WVZ increase from 2.6 ± 0.9 mm/yr in the northeast to 7.0 ± 0.4 mm/yr in the southwest. Conversely, spreading rates in the EVZ decrease from 19.0 ± 2.0 mm/yr in the northeast to 11.0 ± 0.8 mm/yr in the southwest, the direction of ridge propagation. Summed extension rates across the two rift zones are approximately constant and equal to the total plate rate, ∼18–20 mm/yr, consistent with a simple propagating ridge model whereby the WVZ is deactivating in the direction of EVZ propagation. The coupling model confirms results from the simple elastic half‐space model, including relatively shallow locking depths (<5 km) beneath the rift zones, and allows for an estimate of mean viscosity (∼1019–1020 Pa s) beneath the elastic layer. The location of maximum surface velocity gradient in the EVZ, presumably the locus of subsurface magma accumulation and future rifting, does not coincide with the 1783–1784 Lakagígar fissure eruption but is 20 km to the west, on the Bárðabunga‐Veidivötn fissure swarm. This had a small volume eruption in 1862–1864 but a major eruption in 1477 A.D.
Establishing a Photothrombotic ‘ring’ Stroke Model in Adult Mice with Late Spontaneous Reperfusion: Quantitative Measurements of Cerebral Blood Flow and Cerebral Protein Synthesis
Authors: Jiang Wei , Gu Weigang , Hossmann Konstantin-Alexander , Mies Günter , Wester Per
Published: November 2005

This study sought to establish the photothrombotic ‘ring’ stroke model with late spontaneous reperfusion in adult mice. By applying a 3.0-mm diameter laser ring-beam (514 nm, 0.21 mm thick, 0.65 W/cm2) onto the exposed skull for 60 secs with concurrent erythrosin B (4.25 mg/kg) intravenous infusion for 15 secs, the centrally located cortical region within the ring locus was progressively encroached by an annular ring-shaped perfusion deficit. In this region, local cerebral blood flow (ICBF) measured by 1aser-Doppler flowmetry declined promptly after irradiation to 43% of the baseline value at 30 mins poststroke. Using double tracer autoradiography, quantitative ICBF measured with [14C]iodoantipyrine was 46 to 17 to 58 ml/100 g/mins at 4 h to 48 h to 7 days postischemia in this area. Cerebral protein synthesis (CPS), as detected by [3H]leucine incorporation into protein, transiently decreased to 57% to 38% to 112% at 4 h to 48 h to 7 days postischemia in the center region. Morphologically, some neurons in the center region appeared swollen at 4 h. At 48 h, the majority of neurons were severely swollen with eosinophilia and pyknosis, whereas at 7 days poststroke’ the tissue morphology became partly restored. The center within the mouse photothrombotic ring lesion thus exhibits reversible alterations of local CBF, CPS and tissue morphology that are reminiscent of the cortical penumbra in other models of focal cerebral ischemia.
Manipulating the activation barrier for H2(D2) desorption from potassium-modified palladium surfaces
Authors: Pauer G. , Kratzer M. , Winkler A.
Published: November 2005

In this work the permeation and desorption of hydrogen (deuterium) from potassium-modified Pd(111) and polycrystalline palladium surfaces have been studied in the temperature range from 350to523K. Time-of-flight spectroscopy has been used to determine the translational energy distributions of associatively desorbing H2(D2) molecules as a function of the potassium coverage and additional isotropic O2 and CO background pressures. It turned out that the energy distribution of the hydrogen desorption flux is thermalized for the clean Pd surfaces but hyperthermal for the potassium-covered surfaces. The activation barrier for adsorption was found to increase with the potassium coverage but to decrease again in the presence of coadsorbates such as O2 or CO. Especially by choosing different isotropic CO pressures, the effective desorption barrier for hydrogen could be reversibly decreased and increased, which resulted in the equivalent changes of the mean kinetic energies of the desorbing H2 molecules.
On steady flows in smooth-walled magnetrons: Fundamental modes and no-cutoff flows in planar geometry
Authors: Goedecke G. H. , Davis Brian T. , Chen Chiping , Baker C. Vincent
Published: November 2005

The Maxwell equations coupled with the ideal fluid equations for a warm isothermal non-neutral plasma are applied without approximation to predict three modes of time-independent electron flow in smooth-walled planar magnetrons, at any temperature. For all three modes, the equations predict that the fluid flow velocity tangent to the cathode is the Brillouin velocity. One of the modes is the well-known magnetic insulation mode, in which the magnetic field is larger than the Hull cutoff field [Phys. Rev. 18, 31 (1921)], the anode current is essentially zero, and virtually all the electrons reside in a sheath near the cathode. The other two modes exhibit fairly large anode currents. One of these modes is the well-known Child-Langmuir flow [Phys. Rev. 32, 492 (1911); ibid. 21, 419 (1923)], in which the magnetic field is smaller than the Hull cutoff field. The other high-current mode, in which the magnetic field is larger than the Hull cutoff field, has not been discussed previously; in this paper, it is called the “no-cutoff” (NC) mode. Experiments using a thin smooth-walled magnetron were conducted, during which large anode currents were observed even for magnetic fields much larger than the Hull cutoff field. It is shown that NC mode parameters can be adjusted to produce a complete agreement with the experimental results, but that this requires the transverse flow velocity near the cathode to be superthermal and even mildly relativistic for the larger magnetic fields. Matching the experimental values also predicts a number density that is larger near the anode than near the cathode, but is small enough that space-charge effects are negligible in most cases.
Electronic spectroscopy of the deuterated isotopomers of the NO∙methane molecular complex
Authors: Musgrave Adam , Bergeron Denis E. , Wheatley Richard J. , Wright Timothy G.
Published: November 2005

The molecular complexes formed between a nitric oxide molecule and the various deuterated isotopomers of the methane molecule have been studied in a supersonic jet expansion. The electronic spectrum arising from the transition corresponding to a 3s←π* excitation (ÃΣ+2←X̃Π2) located on the NO chromophore has been recorded employing resonance-enhanced multiphoton ionization spectroscopy, with each of CH4, CH3D, CH2D2, CHD3, and CD4 as the complexing partner. Rich spectra are obtained, whose appearance changes in a systematic way as the amount of deuteration increases. Unexpectedly, it was possible to record spectra not only in the parent mass channel, but also in various fragment channels; this also led to the identification of some O atom resonances; and their origin is discussed. Discussion is presented of the structure in the spectra, and its possible sources including hindered internal rotation of the methane and NO moieties, overall rotation of the complex, and tunneling. In addition, some guidance has been gleaned from ab initio calculations, and these are discussed in the light of the experimental results.
The electrostatic potential generated by topological atoms. II. Inverse multipole moments
Authors: Rafat M. , Popelier P. L. A.
Published: November 2005

Quantum chemical topology defines finite atoms, whose bounded electron density generates a well-defined electrostatic potential. A multipole expansion based on spherical tensors provides a potential that is formally convergent outside the divergence sphere. Part I of this series [P. L. A. Popelier and M. Rafat, Chem. Phys. Lett.376, 148 (2003)] showed that a continuous multipole expansion expands the convergence region, thereby allowing the electrostatic potential to be evaluated at short range. Here, we propose a different method, based on “inverse” multipole moments, enabling an expansion that converges everywhere. These moments are defined by inverse (i.e., negative) powers of the magnitude of the position vector describing the electron density inside the atom. We illustrate this technique on nitrogen in N2, oxygen in H2O, and oxygen in the phenolic group of the amino acid tyrosine. The proposed method constitutes a considerable advance over the method presented in Part I.
Reduction of contact resistance at terminations of bismuth wire arrays
Authors: Hasegawa Yasuhiro , Ishikawa Yoshiaki , Shirai Hajime , Morita Hiroyuki , Kurokouchi Akio , Wada Kentarou , Komine Takashi , Nakamura Hiroaki
Published: November 2005

Contact resistance at the terminations of bismuth wire arrays of 25-μm diam is reduced by ion plating of a titanium interlayer 100nm upon the wire ends. One-thousand (1000)-nm-thick copper electrodes are ion plated upon the titanium. Copper probe electrodes are then attached using Pb-Sn solder. The temperature dependences of the Seebeck coefficient and resistance are measured upon heating from 25to300K and the results compared with those for the polycrystalline bulk bismuth sample. The resistivity of the microwire array is found to be 1.37μΩm at 300K. Based on the similarities between the temperature dependences of resistivity and Seebeck coefficient for the wire and bulk samples, contact resistance of the wires is considered to have been completely eliminated. This technique makes it possible to simultaneously estimate the resistivity and Seebeck coefficient for nanowire arrays of thermoelectric materials.
Two-dimensional wave dynamics in thin films. II. Formation of lattices of interacting stationary solitary pulses
Authors: Saprykin Sergey , Demekhin Evgeny A. , Kalliadasis Serafim
Published: November 2005

We develop an inelastic coherent structure theory that describes the weak interaction of the two-dimensional (2D) solitary pulses constructed in Part I. We focus on the interaction between two equilibrium pulses. We project the interaction dynamics on to the zero modes associated with the translational invariances of the system in the streamwise and spanwise directions and we obtain a dynamical system for the locations of the two solitons. We show that in the strongly dispersive case, 2D pulses self-organize into V shapes. Our theoretical findings are in excellent agreement with our time-dependent computations of the fully nonlinear system.
First-principle computation of zero-field splittings: Application to a high valent Fe(IV)-oxo model of nonheme iron proteins
Authors: Aquino Fredy , Rodriguez Jorge H.
Published: November 2005

We report the computational implementation of a combined spin-density-functional theory and perturbation theory (SDFT-PT) methodology for the accurate calculation of zero-field splittings (ZFS) in complexes of the most diverse nature including metal centers in proteins. We have applied the SDFT-PT methodology to study the cation of the recently synthesized complex [FeIV(O)-(TMC)(NCCH3)](OTf)2, [J. Rohde et al., Science 299, 1037 (2003)] which is an important structural and functional analog of high-valent intermediates in catalytic cycles of nonheme iron enzymes. The calculated value (DTheory=28.67cm−1) is in excellent agreement with the unusually large ZFS reported by experiment (DExp=29±3cm−1). The principal component Dzz of the ZFS tensor is oriented along the FeIV=oxo bond indicating that the oxo ligand dominates the electronic structure of the complex.