bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetospheric effects from man‐made ELF/VLF modulation of the auroral electrojet
Authors: Keskinen M. J. , Rowland H. L.
Published: February 2006

A model for the magnetospheric effects of ELF/VLF modulation of the auroral electrojet using high‐power ground‐based high‐frequency radio waves is developed. The effects of ducted topside whistler wave power flux, as generated from ELF/VLF auroral electrojet modulation, on the magnetospheric equatorial pitch angle diffusion coefficient are computed for a range of ELF/VLF modulation frequencies. We find that the precipitation lifetime in the presence of this whistler wave flux is smaller than for purely collisional processes. We find that aspects of the model are in agreement with recent experimental observations.
Very long baseline interferometry as a tool to probe the ionosphere
Authors: Hobiger T. , Kondo T. , Schuh H.
Published: February 2006

In geodetic very long baseline interferometry (VLBI), the observations are performed at two distinct frequencies (2.3 and 8.4 GHz) in order to determine ionospheric delay corrections. This allows information to be obtained from the VLBI observables about the sum of electrons per area unit (total electron content) along the ray path through the ionosphere. Because of the fact that VLBI is a differential technique, the calculated ionospheric corrections depend on the differences of the propagation media over the stations. Additionally, an instrumental delay offset per station causes a bias of the ionospheric measurements. This paper presents a method to estimate ionospheric parameters, that is, values of vertical total electron content from VLBI data, and compares the outcomes to results from other space geodetic techniques. As VLBI observations cover more than two complete solar cycles, the relation to space weather indices on long‐term timescales can be shown.
α1‐, α2‐ and β‐adrenoceptors in the urinary bladder, urethra and prostate
Authors: Michel Martin C. , Vrydag Wim
Published: February 2006

We have systematically reviewed the presence, functional responses and regulation of α1‐, α2‐ and β‐adrenoceptors in the bladder, urethra and prostate, with special emphasis on human tissues and receptor subtypes.

α1‐Adrenoceptors are only poorly expressed and play a limited functional role in the detrusor. α1‐Adrenoceptors, particularly their α1A‐subtype, show a more pronounced expression and promote contraction of the bladder neck, urethra and prostate to enhance bladder outlet resistance, particularly in elderly men with enlarged prostates. α1‐Adrenoceptor agonists are important in the treatment of symptoms of benign prostatic hyperplasia, but their beneficial effects may involve receptors within and outside the prostate.

α2‐Adrenoceptors, mainly their α2A‐subtype, are expressed in bladder, urethra and prostate. They mediate pre‐junctional inhibition of neurotransmitter release and also a weak contractile effect in the urethra of some species, but not humans. Their overall post‐junctional function in the lower urinary tract remains largely unclear.

β‐Adrenoceptors mediate relaxation of smooth muscle in the bladder, urethra and prostate. The available tools have limited the unequivocal identification of receptor subtypes at the protein and functional levels, but it appears that the β3‐ and β2‐subtypes are important in the human bladder and urethra, respectively. β3‐Adrenoceptor agonists are promising drug candidates for the treatment of the overactive bladder.

We propose that the overall function of adrenoceptors in the lower urinary tract is to promote urinary continence. Further elucidation of the functional roles of their subtypes will help a better understanding of voiding dysfunction and its treatment.

British Journal of Pharmacology(2006)147, S88–S119. doi:10.1038/sj.bjp.0706619
Molecular mechanisms of detrusor and corporal myocyte contraction: identifying targets for pharmacotherapy of bladder and erectile dysfunction
Authors: Christ George J. , Hodges Steve
Published: February 2006

The Post‐Genomic age presents many new challenges and opportunities for the improved understanding, diagnosis and treatment of human disease. The long‐term goal is to identify molecular correlates of disease processes, and use this information to develop novel and more effective therapeutics. A major hurdle in this regard is ensuring that the molecular targets of interest are indeed relevant to the physiology and/or pathophysiology of the processes being studied, and, moreover, to determine if they are specific to the tissue/organ being investigated. As a first step in this direction, we have reviewed the literature pertaining to bladder and erectile physiology/pharmacology and dysfunction and attempted to summarize some of the critical molecular mechanisms regulating detrusor and corporal myocyte tone. Because of the vast amount of published data, we have limited the scope of this review to consideration of the calcium‐mobilizing and calcium‐sensitizing pathways in these cells. Despite obvious differences in phenotypic characteristics of the detrusor and corporal myocyte, there are some common molecular changes that may contribute to, for example, the increased myocyte contractility characteristic of bladder and erectile dysfunction (i.e. increased Rho kinase activity and decreased K+channel function). Of course, there are also some important distinctions in the pathways that modulate contractility in these two cell types (i.e. the contribution of ryanodine‐sensitive calcium stores and the nitric oxide/cGMP pathways). This report highlights some of these similarities and distinctions in the hope that it will encourage scientific discourse and research activity in this area, eventually leading to an improved quality of life for those millions of individuals that are afflicted with bladder and erectile dysfunction.

British Journal of Pharmacology(2006)147, S41–S55. doi:10.1038/sj.bjp.0706627
Fully ultrahigh-vacuum-compatible fabrication of submicrometer-spaced electrical contacts
Authors: Gärtner C. , Hoffman R. , Pérez-Willard F. , Sauter M. , Sürgers C. , Löhneysen H. v.
Published: February 2006

We present an approach by which submicrometer-spaced electrical contacts can be fabricated on virtually any surface under ultrahigh-vacuum conditions. The metallic contacts are formed by subsequent deposition through a macroscopic mask and a nanostructured stencil mask. The stencil mask with a high aspect ratio was obtained by nanopatterning of suspended low-stress Si3+xN4−x membranes with a focused ion-beam system. The fabricated contacts can be electrically connected in situ by simply exchanging the mask carrier by a second, spring-loaded, carrier.
Magnetic diagnostic system of the DIII-D tokamak
Authors: Strait E. J.
Published: February 2006

External measurements of the magnetic field surrounding a hot, magnetically confined plasma yield important information about the state of the plasma, since the external field is generated in part by electric currents within the plasma itself. Therefore, magnetic diagnostics are an essential part of both the operation and the physics experiments in tokamaks and other magnetic confinement devices. The magnetic diagnostic system of the DIII-D tokamak includes approximately 250 inductive sensors of various types: axisymmetric poloidal flux loops, diamagnetic-flux loops, magnetic probes and saddle loops for the measurement of local magnetic field, and Rogowski loops for the measurement of coil currents and plasma current. The primary uses of the data include plasma shape and position control with a real-time digital control system, postdischarge equilibrium reconstruction, spectrum analysis in time and space of plasma instabilities, and direct feedback control of slowly growing instabilities. The sensors, instrumentation, calibration, applications, and operating experience are described.
The photodissociation dynamics of NO2 at 308nm and of NO2 and N2O4 at 226nm
Authors: Brouard M. , Cireasa R. , Clark A. P. , Preston T. J. , Vallance C.
Published: February 2006

Velocity-map ion imaging has been applied to the photodissociation of NO2 via the first absorption band at 308nm using (2+1) resonantly enhanced multiphoton ionization detection of the atomic O(PJ3) products. The resulting ion images have been analyzed to provide information about the speed distribution of the O(PJ3) products, the translational anisotropy, and the electronic angular momentum alignment. The atomic speed distributions were used to provide information about the internal quantum-state distribution in the NO coproducts. The data were found to be consistent with an inverted NO vibrational quantum-state distribution, and thereby point to a dynamical, as opposed to a statistical dissociation mechanism subsequent to photodissociation at 308nm. Surprisingly, at this wavelength the O-atom electronic angular momentum alignment was found to be small. Probe-only ion images obtained under a variety of molecular-beam backing-pressure conditions, and corresponding to O atoms generated in the photodissociation of either the monomer, NO2, or the dimer, N2O4, at 226nm, are also reported. For the monomer, where 226nm corresponds to excitation into the second absorption band, the kinetic-energy release distributions are also found to indicate a strong population inversion in the NO cofragment, and are shown to be remarkably similar to those previously observed in the wavelength range of 193–248nm. Mechanistic implications of this result are discussed. At 226nm it has also been possible to observe directly O atoms from the photodissociation of the dimer. The O-atom velocity distribution has been analyzed to provide information about its production mechanism.
Improved signal analysis for the calibration of the motional Stark effect diagnostic
Authors: Shi Yuejiang
Published: February 2006

A Stokes vector and Mueller matrix formalism are adopted to model the optical train of the motional stark effect (MSE) system. The method to find all four elements of Stokes vectors and optical parameters of MSE system is presented in this article. A new fitting model for MSE calibration is discussed. A method for the measurement of offset angle of MSE is also presented. The nonideal effects of the background unpolarized and polarized light of non-Stark effect are analyzed.
Characterization of wave-front corrected 100 TW, 10 Hz laser pulses with peak intensities greater than 1020W∕cm2
Authors: Akahane Yutaka , Ma Jinglong , Fukuda Yuji , Aoyoma Makoto , Kiriyama Hiromitsu , Sheldakova Julia V. , Kudryashov Alexis V. , Yamakawa Koichi
Published: February 2006

An improvement of laser-focused peak intensity has been achieved in a JAERI 100 TW Ti:sapphire chirped-pulse amplifier chain with a feedback controlled adaptive optics system operating at a 10 Hz repetition rate. The Strehl ratio was enhanced to 0.8 by means of a Bimorph deformable mirror with a Shack-Hartmann wave-front sensor. Measurements of optical parameters of the laser pulse and an experimental tunneling ionization yield of helium have practically confirmed focusing to ultrarelativistic intensities of over 1020W∕cm2 within 16% accuracy.
Theory of photoinduced heterogeneous electron transfer
Authors: Sebastian K. L. , Tachiya Masanori
Published: February 2006

We consider electron injection into the conduction band of a semiconductor, from an electronically excited state of a dye molecule, adsorbed on its surface. For arbitrary width of the conduction band, the survival probability of the excited state can be calculated using a Green’s-function approach. We show that the existence of a split-off state can play an important role in the total injection probability. In the wide band limit, the survival probability decays exponentially, but for finite band widths it does not. We further investigate the effect of vibrations on the process. A Green’s operator technique may be used to solve this too exactly. We show that the problem may be reduced to a non-Hermitian eigenvalue problem for the vibrational states alone. Exact results can be obtained for arbitrary bandwidth and for a few vibrational degrees of freedom. In the wide band limit, the dynamics is particularly simple and we find that (1) the survival probability of the excited state is unchanged by the inclusion of vibrational motion, but (2) each vibrational state now has a finite lifetime. Numerical results are presented for the effects of reorganization energy, energy of the injecting level, and the variation of the matrix element for the electron injection, on the survival probability of the electron in the excited state. As an illustration of the approach, we also present results of numerical calculation of the absorption spectrum of perylene adsorbed on TiO2 and compare it with experimental results.
Oscillatory thickness dependence of the coercive field in magnetic three-dimensional antidot arrays
Authors: Zhukov A. A. , Goncharov A. V. , de Groot P. A. J. , Ghanem M. A. , Bartlett P. N. , Boardman R. , Fangohr H. , Novosad V. , Karapetrov G.
Published: February 2006

Recent developments in magnetic applications, such as data storage, sensors, and transducers, are stimulating intense research into magnetism on submicrometer-length scales. Emerging self-assembly fabrication techniques have been proposed as viable, low-cost methods to prepare such submicron structures. In this letter we present studies on magnetic nanostructures with 3D architectures, fabricated using a self-assembly template method. We find that the patterning transverse to the film plane, which is a unique feature of this method, governs the magnetic behavior. In particular, the coercive field, a key parameter for magnetic materials, was found to demonstrate an oscillatory dependence on film thickness.
Investigation of a polythiophene interface using photoemission spectroscopy in combination with electrospray thin-film deposition
Authors: Cascio A. J. , Lyon J. E. , Beerbom M. M. , Schlaf R. , Zhu Y. , Jenekhe S. A.
Published: February 2006

The conjugated polymer poly(3-hexylthiophene) (P3HT) was deposited in several steps onto a highly oriented pyrolytic graphite (HOPG) substrate directly from solution in high vacuum, using an electrospray thin-film deposition system. The deposition system was attached to a photoemission spectroscopy setup via in situ sample transfer, allowing characterization in between deposition steps with x-ray and ultraviolet photoemission spectroscopy. The resultant series of spectra enabled the determination of the ionization energy, work function, and highest occupied molecular orbital binding energy of the P3HT overlayer, while giving detailed insight into the orbital alignment and dipole formation at the P3HT/HOPG contact.
Direct imaging of phase separation in ZnCdO layers
Authors: Bertram F. , Giemsch S. , Forster D. , Christen J. , Kling R. , Kirchner C. , Waag A.
Published: February 2006

A direct correlation of structural and optical properties of MOCVD-grown ZnCdO-layers with a systematic variation of Cd-content has been achieved on a microscopic scale using highly spatially and spectrally resolved cathodoluminescence. The ZnCdO layer luminescence measured in cathodoluminescence wavelength images reveals strong lateral fluctuations directly visualizing local band gap fluctuation as a consequence of different local Cd incorporation. We give direct evidence for a chemical phase separation into Cd-rich and Cd-poor nanodomains in ZnCdO.
Sharp waveguide bends induced by spatial solitons
Authors: Jäger Robert , Gorza Simon-Pierre , Cambournac Cyril , Haelterman Marc , Chauvet Mathieu
Published: February 2006

We experimentally demonstrate the ability of a self-guided laser beam to induce waveguides with sharp bends. The beam is a two-dimensional photorefractive screening-photovoltaic bright spatial soliton generated inside a biased lithium-niobate crystal shaped as a prism. The soliton robustness against total internal reflections is shown to leave place to a low-loss unimodal waveguide undergoing multiple zero-radius 90° turns.
Wetting and crystallization at grain boundaries: Origin of aluminum-induced crystallization of amorphous silicon
Authors: Wang J. Y. , He D. , Zhao Y. H. , Mittemeijer E. J.
Published: February 2006

It has been shown experimentally that the grain boundaries in aluminium in contact with amorphous silicon are the necessary agents for initiation of the crystallization of silicon upon annealing temperatures as low as 438K. Thermodynamic analysis has shown (i) that Si can “wet” the Al grain boundaries due to the favorable Si∕Al interface energy as compared to the Al grain-boundary energy and (ii) that Si at the Al grain boundaries can maintain its amorphous state up to a thickness of about 1.0nm. Beyond that thickness crystalline Si develops at the Al grain boundaries.
Reducing the operational magnetic field in the prototype magnetocaloric system Gd5Ge4 by approaching the single cluster size limit
Authors: Moore J. D. , Perkins G. K. , Bugoslavsky Y. , Chattopadhyay M. K. , Roy S. B. , Chaddah P. , Pecharsky V. K. , Gschneidner K. A. , Cohen L. F.
Published: February 2006

We studied polycrystalline samples of the prototype magnetocaloric system Gd5Ge4 using scanning Hall imaging and global magnetometry. The magnetic field required to complete the phase transition that is critical for magnetocaloric application is reduced by up to 20% when small fragments, each consisting of several randomly oriented crystallites, are removed from the bulk. The removal of competing strain fields from neighboring grains when the fragment is embedded in the bulk underlies the observation. We support the results by showing local Hall imaging of phase separation in the bulk. When the bulk is ground into a fine powder, the effect vanishes.
Magnetization reversal of uncompensated Fe moments in exchange biased Ni∕FeF2 bilayers
Authors: Arenholz Elke , Liu Kai , Li Zhipan , Schuller Ivan K.
Published: February 2006

The magnetization reversal of uncompensated Fe moments in exchange biased Ni∕FeF2 bilayers was determined using soft x-ray magnetic circular and linear dichroism. The hysteresis loops resulting from the Fe moments are almost identical to those of the ferromagnetic Ni layer. However, a vertical loop shift indicates that some Fe moments are pinned in the antiferromagnetically ordered FeF2. The pinned moments are oriented antiparallel to small cooling fields, leading to negative exchange bias, but parallel to large cooling fields, resulting in positive exchange bias. No indication for the formation of a parallel antiferromagnetic domain wall in the FeF2 layer upon magnetization reversal in the Ni layer was found.
Resonantly-enhanced transmission through a periodic array of subwavelength apertures in heavily-doped conducting polymer films
Authors: Matsui Tatsunosuke , Vardeny Z. Valy , Agrawal Amit , Nahata Ajay , Menon Reghu
Published: February 2006

We observed resonantly-enhanced terahertz transmission through two-dimensional (2D) periodic arrays of subwavelength apertures with various periodicities fabricated on metallic organic conducting polymer films of polypyrrole heavily doped with PF6 molecules [PPy(PF6)]. The “anomalous transmission” spectra are in good agreement with a model involving surface plasmon polariton excitations on the film surfaces. We also found that the ‘anomalous transmission’ peaks are broader in the exotic metallic PPy(PF6) films compared to those formed in 2D aperture array in regular metallic films such as silver, showing that the surface plasmon polaritons on the PPy(PF6) film surfaces have higher attenuation.
Phenomenological model for the dielectric enhancement in compositionally graded ferroelectric films
Authors: Wong C. K. , Shin F. G.
Published: February 2006

The dielectric enhancement observed in compositionally graded ferroelectric films is explained by use of a multilayer model. The finite size effect of the ferroelectric layers has been taken into account. This is tackled by the employment of Landau–Ginzburg thermodynamic theory for each layer. The calculated dielectric susceptibility of the graded film reveals significant enhancement for temperatures below the phase transition point, and is greater in a continuously graded film than in one with a step gradient in composition.
Long-term residual value of copper fertiliser for production of wheat grain
Authors: Brennan R. F.
Published: February 2006

A long-term field experiment on acutely copper deficient soil commenced in 1967 in south-western Western Australia to measure the residual value of fertiliser copper for grain production of spring wheat (Triticum aestivum L.). Before sowing the first wheat crop, 6 amounts of copper [0, 0.69, 1.38, 2.07, 2.75 and 4.75 kg copper/ha as copper sulfate (25% copper)] were applied to large main plots when the fertiliser was placed (drilled) with the seed during sowing. Thereafter, wheat was grown every fourth year in rotation with subterranean clover (Trifolium subterraneum L.)-based pasture. When each wheat crop was sown in subsequent years, 4 amounts of copper were drilled with the sown seed in subplots within each of the 6 main plots, using new suplots for each wheat crop that were not previously treated with copper since the initial application in 1967. The effectiveness for producing wheat grain from the 6 original amounts of copper was calculated relative to freshly-applied copper by estimating the amount of original copper and freshly-applied copper required to produce the same grain yield. Results for the first 12 years have been published (Gartrell 1980); results for years 16–32 are presented in this paper.
For the first 12 years large wheat grain yield increases were only obtained to freshly-applied copper in the original nil-copper main plots. For the first time, in the 16th year, copper responses also occurred to freshly-applied copper in the original 0.69 kg copper/ha main plots. The recommended amount of copper applied to wheat, for the soil type used, was 1.38 kg copper/ha and this supplied sufficient copper for grain production for 28 years. At this stage, grain yield responses to freshly-applied copper occurred for the first time in these main plots. The copper removal in grain of each wheat crop only accounted for about 2–3% of the original 1.38 kg copper/kg treatment. Otherwise, all freshly-applied copper treatments were on the maximum yield plateau because wheat roots accessed enough copper for grain production from soil treated with the original copper treatments. In years 4–16, the original copper treatments were more effective than freshly-applied copper because cultivating soil to sow wheat mixed the original treatments through soil increasingly improving interception of the original copper treatments in soil by plant roots. However, in years 24–32, freshly-applied copper was more effective as the residual value of the original copper treatments continued to decrease due to continued slow reaction of the original copper treatments with soil.
For wheat at the flag leaf stage, the concentrations of copper in the youngest expanded wheat leaf blades that were related to 90% of the maximum grain yield (prognostic value) was about 1.4 mg/kg.
Monitoring the direct and indirect damage of DNA bases and polynucleotides by using time-resolved infrared spectroscopy
Authors: Kuimova Marina K. , Cowan Alexander J. , Matousek Pavel , Parker Anthony W. , Sun Xue Zhong , Towrie Michael , George Michael W.
Published: February 2006

The nucleotide 5′-dGMP and polynucleotide poly(dGdC)·poly(dGdC) have been irradiated by using a 200-fs, 200-nm laser pulses and spectrally characterized by using time-resolved infrared spectroscopy. Under the experimental conditions, 200-nm excitation generates both electronic excited states and radical cations through photoionization; the former decay rapidly to vibrationally hot ground state. By using infrared signatures we have been able to follow these processes, and at time scales of >1 ns we observe an infrared marker band at 1,702 cm
−1
within both 5′-dGMP and the polynucleotide assigned to a photoionized product of guanine. This transient has also been reproduced through indirect chemistry through the reaction with photogenerated carbonate radical with 5′-dGMP. The ability to use time-resolved infrared spectroscopy in this way paves the way for developing solution-phase studies to investigate both direct and indirect radiation chemistry of DNA.
Hypoxia-inducible myoglobin expression in nonmuscle tissues
Authors: Fraser Jane , Vieira de Mello Luciane , Ward Deborah , Rees Huw H. , Williams Daryl R. , Fang Yongchang , Brass Andrew , Gracey Andrew Y. , Cossins Andrew R.
Published: February 2006

Myoglobin (Myg) is an oxygen-binding hemoprotein that is widely thought to be expressed exclusively in oxidative skeletal and cardiac myocytes, where it plays a key role in coping with chronic hypoxia. We now show in a hypoxia-tolerant fish model, that Myg is also expressed in a range of other tissues, including liver, gill, and brain. Moreover, expression of Myg transcript was substantially enhanced during chronic hypoxia, the fold-change induction being far greater in liver than muscle. By using 2D gel electrophoresis, we have confirmed that liver expresses a protein corresponding to the Myg-1 transcript and that it is significantly up-regulated during hypoxia. We have also discovered a second, unique Myg isoform, distinct from neuroglobin, which is expressed exclusively in the neural tissue but whose transcript expression was unaffected by environmental hypoxia. Both observations of nonmuscle expression and a brain-specific isoform are unprecedented, indicating that Myg may play a much wider role than previously understood and that Myg might function in the protection of tissues from deep hypoxia and ischemia as well as in reoxygenation and reperfusion injury.
Comparative genomics provides evidence for close evolutionary relationships between the urotensin II and somatostatin gene families
Authors: Tostivint Hervé , Joly Lucille , Lihrmann Isabelle , Parmentier Caroline , Lebon Alexis , Morisson Mireille , Calas André , Ekker Marc , Vaudry Hubert
Published: February 2006

Although urotensin II (UII) and somatostatin 1 (SS1) exhibit some structural similarities, their precursors do not show any appreciable sequence identity and, thus, it is widely accepted that the UII and SS1 genes do not derive from a common ancestral gene. The recent characterization of novel isoforms of these two peptides, namely urotensin II-related peptide (URP) and somatostatin 2 (SS2)/cortistatin (CST), provides new opportunity to revisit the phylogenetic relationships of UII and SS1 using a comparative genomics approach. In the present study, by radiation hybrid mapping and
in silico
sequence analysis, we have determined the chromosomal localization of the genes encoding UII- and somatostatin-related peptides in several vertebrate species, including human, chicken, and zebrafish. In most of the species investigated, the UII and URP genes are closely linked to the SS2/CST and SS1 genes, respectively. We also found that the UII-SS2/CST locus and the URP/SS1 locus are paralogous. Taken together, these data indicate that the UII and URP genes, on the one hand, and the SS1 and SS2/CST genes, on the other hand, arose through a segmental duplication of two ancestral genes that were already physically linked to each other. Our results also suggest that these two genes arose themselves through a tandem duplication of a single ancestral gene. It thus appears that the genes encoding UII- and somatostatin-related peptides belong to the same superfamily.
Stem cell factor receptor induces progenitor and natural killer cell-mediated cardiac survival and repair after myocardial infarction
Authors: Ayach Bilal B. , Yoshimitsu Makoto , Dawood Fayez , Sun Mei , Arab Sara , Chen Manyin , Higuchi Koji , Siatskas Christopher , Lee Paul , Lim Hilda , Zhang Jane , Cukerman Eva , Stanford William L. , Medin Jeffrey A. , Liu Peter P.
Published: February 2006

Inappropriate cardiac remodeling and repair after myocardial infarction (MI) predisposes to heart failure. Studies have reported on the potential for lineage negative, steel factor positive (
c
-
kit
+
) bone marrow-derived hematopoetic stem∕progenitor cells (HSPCs) to repair damaged myocardium through neovascularization and myogenesis. However, the precise contribution of the
c-kit
signaling pathway to the cardiac repair process has yet to be determined. In this study, we sought to directly elucidate the mechanistic contributions of
c-kit
+
bone marrow-derived hematopoetic stem∕progenitor cells in the maintenance and repair of damaged myocardium after MI. Using
c-kit
-deficient mice, we demonstrate the importance of
c-kit
signaling in preventing ventricular dilation and hypertrophy, and the maintenance of cardiac function after MI in
c-kit
-deficient mice. Furthermore, we show phenotypic rescue of cardiac repair after MI of
c-kit
-deficient mice by bone marrow transplantation of wild-type HSPCs. The transplanted group also had reduced apoptosis and collagen deposition, along with an increase in neovascularization. To better understand the mechanisms underlying this phenotypic rescue, we investigated the gene expression pattern within the infarcted region by using microarray analysis. This analysis suggested activation of inflammatory pathways, specifically natural killer (NK) cell-mediated mobilization after MI in rescued hearts. This finding was confirmed by immunohistology and by using an NK blocker. Thus, our investigation revealed a previously uncharacterized role for
c-kit
signaling after infarction by mediating bone marrow-derived NK and angiogenic cell mobilization, which contributes to improved remodeling and cardiac function after MI.
Evaluation of an Intervention Designed to Decrease the Rate of Nosocomial Methicillin-ResistantStaphylococcus aureusInfection by Encouraging Decreased Fluoroquinolone Use
Authors: Madaras-Kelly Karl J. , Remington Richard E. , Lewis Pamela G. , Stevens Dennis L.
Published: February 2006

Objective.

Society for Health Care Epidemiology guidelines recommend decreasing the use of fluoroquinolone antibiotics in institutions where methicillin-resistantStaphylococcus aureus(MRSA) is endemic. We evaluated whether an intervention to limit fluoroquinolone use was associated with a lower rate of nosocomial MRSA infection and summarized changes in antibiotic use, changes in other variables potentially correlated with a lower rate of MRSA infection, and rates of nosocomial infections due to other pathogens.

Design.

Single-center quasi-experimental design. A time series of nosocomial MRSA infections was measured at monthly intervals from July 2001 through June of 2004; there were 80 MRSA infections recorded. Segmented regression analysis (ie, quasi-Poisson generalized linear models) was used to evaluate variables possibly associated with the nosocomial MRSA infection rate.

Setting.

An 87-bed Veterans Affairs teaching hospital with an extended-care facility.

Intervention.

A physician-directed computer-generated intervention designed to limit the use of fluoroquinolone antibiotics was initiated, and institutional changes in antibiotic use and nosocomial MRSA infection rates were tracked.

Results.

After the intervention, fluoroquinolone use decreased by approximately 34%, and levofloxacin use decreased by approximately 50%. Decreased fluoroquinolone use was offset by increased cephalosporin, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole use. The nosocomial MRSA infection rate decreased from 1.37 to 0.63 episodes per 1,000 patient-days after the study intervention (P= .02). Coagulase-negativeStaphylococcusandEnterococcusinfection rates also decreased. However, the rate of infection with gram-negative organisms increased. The rate of MRSA infection was positively correlated with levofloxacin use (P= .01) and azithromycin use (P= .08), whereas it was negatively correlated with summer season (P= .05). In a subsequent model, the rate of MRSA infection was negatively correlated with the study intervention (P= .04).

Conclusion.

Reduction in the institutional use of fluoroquinolones may be associated with a lower nosocomial MRSA infection rate.
A Study of the Relationship Between Environmental Contamination with Methicillin-ResistantStaphylococcus aureus(MRSA) and Patients' Acquisition of MRSA
Authors: Hardy Katherine J. , Oppenheim Beryl A. , Gossain Savita , Gao Fang , Hawkey Peter M.
Published: February 2006

Objective.

The study aimed to examine the presence of methicillin-resistantStaphylococcus aureus(MRSA) in the environment and its relationship to patients' acquisition of MRSA.

Design.

A prospective study was conducted in a 9-bed intensive care unit for 14 months. At every environmental screening, samples were obtained from the same 4 sites in each bed space. Patients were screened at admission and then 3 times weekly. All environmental and patient strains were typed using pulsed-field gel electrophoresis.

Results.

MRSA was isolated from the environment at every environmental screening, when both small and large numbers of patients were colonized. Detailed epidemiological typing of 250 environmental and 139 patient isolates revealed 14 different pulsed-field gel electrophoresis profiles, with variants of EMRSA-15 being the predominant type. On only 20 (35.7%) of 56 occasions were the strains isolated from the patients and the strains isolated from their immediate environment indistinguishable. There was strong evidence to suggest that 3 of 26 patients who acquired MRSA while in the intensive care unit acquired MRSA from the environment.

Conclusions.

This study reveals widespread contamination of the hospital environment with MRSA, highlights the complexities of the problem of contamination, and confirms the need for more-effective cleaning of the hospital environment to eliminate MRSA.
Chest Tube–Related Empyema Due to Methicillin-ResistantStaphylococcus aureus:Could the Chest Tube Be Coated With Antiseptics?
Authors: Torres Harrys A. , Hanna Hend A. , Graviss Linda , Chaiban Gassan , Hachem Ray , Chemaly Roy F. , Girgawy Essam , Raad Issam I.
Published: February 2006

We reviewed the epidemiology, clinical manifestations, and outcomes of 3 cases of chest tube–related empyema due to methicillin-resistantStaphylococcus aureus(MRSA). Antiseptic-impregnated chest tubes were inserted in cultures containing MRSA isolates from these 3 patients, and zone of inhibition were measured. Chest tube–related MRSA empyema might complicate tube thoracostomy, and coating the chest tube with antiseptic agents could prevent this complication.
Cluster homology: An overview of the construction and results
Authors: Cornea Octav , Lalonde François
Published: February 2006

We associate, to a Lagrangian submanifold

L
L

of a symplectic manifold, a new homology, called the cluster homology of

L
L

, which is invariant up to ambient symplectic diffeomorphisms. We discuss various applications concerning analytical, topological, and dynamical properties of Lagrangian submanifolds. We also deduce a new universal Floer homology, defined without obstruction, for pairs of Lagrangian submanifolds.
Intranasal Zinc and Anosmia: The Zinc‐Induced Anosmia Syndrome
Authors: Alexander Thomas H. , Davidson Terence M.
Published: February 2006

Objective: Commercial preparations of intranasal zinc gluconate gel are marketed as a remedy for the common cold. However, intranasal zinc has been reported as a cause of anosmia in humans and animals. Seventeen patients presenting with anosmia after the use of intranasal zinc gluconate are described.

Methods: The authors conducted a retrospective case series of patients presenting to a nasal dysfunction clinic and conducted complete history and physical examination on all patients, including nasal endoscopy. All patients underwent detailed odor threshold and identification testing.

Results: Threshold and identification testing revealed impaired olfaction in all patients. Inflammatory and traumatic causes of anosmia were excluded based on history, physical examination, and imaging. All patients diagnosed with zinc‐induced anosmia or hyposmia reported sniffing deeply when applying the gel. This was followed by an immediate sensation of burning lasting minutes to hours. Loss of sense of smell was then perceived within 48 hours. Seven of 17 patients never developed symptoms of an upper respiratory infection.

Conclusions: The zinc‐induced anosmia syndrome, characterized by squirt, sniff, burn, and anosmia, occurs after the exposure of olfactory epithelium to zinc cation. It can be distinguished from postviral anosmia based on history.
Searching the Literature Using Medical Subject Headings versus Text Word with PubMed
Authors: Chang Angela A. , Heskett Karen M. , Davidson Terence M.
Published: February 2006

Objective/Hypothesis: This study was conducted to investigate the performance of two search strategies in the retrieval of information from the National Library of Medicine (NLM) on otolaryngology–head and neck surgery related conditions and diagnoses using PubMed.

Methods: Two search strategies—one based on the use of Medical Subject Headings (MeSH) and the second based on text word searching—were compared.

Results: The MeSH search provided a more efficient search than the text word search.

Conclusions: Head and neck surgeons can most efficiently search the NLM using PubMed as a search engine by initiating the search with MeSH terms. Once a key article is identified, the searcher should use the “Related Articles” feature.
Cochlear Preservation After Meningitis: An Animal Model Confirmation of Adjunctive Steroid Therapy
Authors: Addison John , Kim Harold H. , Richter Claus‐Peter
Published: February 2006

Objective/Hypothesis: The objective of the present study was to determine whether treating pneumococcal meningitis with a combined antibiotic and steroid regime will prevent cochlear damage, a common pneumococcal meningitis side effect.

Study Design: This was a prospective animal study.

Methods: Gerbils were randomly assigned to three experimental groups. Animals in group 1, the control animals, received intrathecal saline injections. Animals in groups 2 and 3 received intrathecal injections of Streptococcus pneumoniae to induce meningitis. Although group 2 solely was treated for 7 days with intraperitoneal penicillin injections (48,0000 units), group 3 received, in addition to the antibiotic for 4 days, 0.5 mg/kg intraperitoneal dexamethasone injections. Three months after the meningitis was induced, the animals' cochlear function was determined using auditory brainstem responses (ABRs). Fifteen frequencies were tested, five octaves at three steps per octave between 2 and 50 kHz.

Results: ABR thresholds were significantly elevated only in group 2. When compared with group 1, ABR thresholds were 19 dB higher (P < .05). Frequencies at the low‐frequency end of the hearing range were affected more than the midfrequencies. Animals that received dexamethasone had 2‐dB higher thresholds than the control group (P > .05).

Conclusions: Dexamethasone therapy in conjunction with antibiotic therapy preserves cochlear function in cases of S. pneumoniae meningitis in the Mongolian gerbil model.
Early Laryngeal Inhalation Injury and its Correlation with Late Sequelae
Authors: Valdez Tulio A. , Desai Urmen , Ruhl Charles M. , Nigri Peter T.
Published: February 2006

Objective: Inhalation injury can permanently alter normal laryngeal function. The aim of this study was to examine the early changes in voice, swallowing, and breathing in laryngeal inhalation injuries.

Study Design: This was a prospective analysis of nine patients with inhalation injuries at a tertiary care institution.

Methods: Laryngeal function of patients admitted for inhalation injury requiring intubation was documented using videostroboscopy and swallowing evaluation by the speech pathology service. Bronchoscopy was used to classify the degree of inhalation injury. Association among total body surface area, facial burns, severity of laryngotracheal injuries, and loss of function was attempted.

Results: All three patients with severe tracheal inhalation injury presented persistent hoarseness at 1‐year follow up with abnormal videostroboscopy findings. No association was found between inhalation injury and total body surface area burned. None of the patients in this series presented permanent swallowing dysfunction.

Conclusion: The otolaryngologist plays an important role in the initial and long‐term management of inhalation injuries. Inhalation injuries should be managed in a multidisciplinary fashion. There may be a correlation between the degree of tracheal injury and laryngeal injury and hoarseness.
Health‐Related Quality of Life after Polypectomy with and without Additional Surgery
Authors: Browne John Patrick , Hopkins Claire , Slack Robert , Topham John , Reeves Barnaby , Lund Valerie , Brown Peter , Copley Lynn , van der Meulen Jan
Published: February 2006

Objective: The objective of this study was to compare the health‐related quality of life of patients undergoing simple polypectomy with that of patients undergoing polypectomy with additional surgery.

Study Design: This was a prospective, multicenter cohort study of adults undergoing sinonasal surgery.

Methods: Eight hundred forty‐four patients received simple polypectomy and 1,004 patients received polypectomy with additional surgery. Health‐related quality of life was compared at 12 and 36 months after surgery using the Sino‐Nasal Outcome Test (SNOT‐22). Total SNOT‐22 scores may range from zero to 110 with lower scores representing better outcomes. We used linear regression to adjust postoperative SNOT‐22 scores for baseline characteristics. When comparing the difference between the two surgical techniques, positive SNOT‐22 scores represent a better outcome for those undergoing additional surgery.

Results: There were only small differences between the two groups at 12 months (difference in SNOT‐22 −0.5; 95% confidence interval [CI] = −2.3–1.3; P = .58) and 36 months after surgery (difference −2.1; 95% CI = −4.4–0.2; P = .08). The additional surgery group had a slightly higher risk of excessive perioperative bleeding (8.6% vs. 6.0%; P = .04) but a slightly lower risk of revision surgery within 36 months (10.4% vs. 13.3%; P = .12).

Conclusions: Nasal polypectomy with additional surgery seems to have no benefit over simple polypectomy in terms of health‐related quality of life improvement for patients with nasal polyposis.
Incongruence between Histologic and Endoscopic Diagnoses of Barrett's Esophagus Using Transnasal Esophagoscopy
Authors: Halum Stacey L. , Postma Gregory N. , Bates Dwight D. , Koufman Jamie A.
Published: February 2006

Objectives: The symptoms, patterns of reflux, and clinical manifestations of laryngopharyngeal reflux (LPR) differ from those of gastroesophageal reflux disease (GERD) in many ways. The purposes of this study were to determine the prevalence of Barrett's esophagus in patients with LPR using transnasal esophagoscopy (TNE) and to determine if there is agreement between TNE clinical findings and pathology results when using TNE for Barrett's screening.

Study Design: This study involved a retrospective review of the records of 200 consecutive patients with LPR undergoing esophageal screening.

Methods: The prevalence of patients with findings clinically suspicious for Barrett's and the biopsy results for those patients were reviewed.

Results: Of the 200 patients with LPR who were screened with TNE, 10% (20 of 200) had findings suspicious for Barrett's esophagus, and, of those, only 30% (six of 20) had biopsy‐proven Barrett's metaplasia.

Conclusion: Although TNE may be a useful screening tool for Barrett's, there is incongruence between TNE findings and biopsy results, which likely reflects suboptimal biopsy methods with TNE. New biopsy techniques such as the CDx brush biopsy may enhance the sensitivity of TNE biopsies, and future studies are needed in this area.
Assessment of Intraoperative Safety in Transoral Robotic Surgery
Authors: Hockstein Neil G. , O'Malley Bert W. , Weinstein Gregory S.
Published: February 2006

Introduction: Robotic technology has been safely integrated into thoracic and abdominopelvic surgery, and the early experience has been very promising with very rare complications related to robotic device failure. Recently, several reports have documented the technical feasibility of transoral robotic surgery (TORS) with the daVinci Surgical System. Proposed pharyngeal and laryngeal applications include radical tonsillectomy, base‐of‐tongue resection, supraglottic laryngectomy, and phonomicrosurgery. The safety of transoral placement of the robotic endoscope and instruments has not been established. Potential risks specific to the transoral use of the surgical robot include facial skin laceration, tooth injury, mucosal laceration, mandible fracture, cervical spine fracture, and ocular injury. We hypothesize that these particular risks of transoral surgery are similar with robotic assistance compared with conventional transoral surgery.

Methods: To test this hypothesis, we attempted to intentionally injure a human cadaver with the daVinci Surgical System by impaling the facial skin and pharyngeal and laryngeal mucosa with the robotic instruments and endoscope. We also attempted to extract or fracture teeth and fracture the cadaver's mandible and cervical spine by applying maximal pressure and torque with the robotic arms. Experiments were documented with still and video photography.

Results: Impaling the cadaver's skin and mucosa resulted in only superficial lacerations. Tooth, mandible, and cervical spine fracture could not be achieved.

Conclusions: Initial experiments performing TORS on a human cadaver with the daVinci Surgical System demonstrate a safety profile similar to conventional transoral surgery. Additionally, we discuss several strategies to increase patient safety in TORS.
Protected areas and regional avian species richness in South Africa
Authors: Evans Karl L , Rodrigues Ana S.L , Chown Steven L , Gaston Kevin J
Published: February 2006

Protected areas are generally regarded as essential for the long-term maintenance of biodiversity. Evidence for their effectiveness in this regard is, however, somewhat equivocal. Here, we document the relationship between the proportion of protected land and species richness in a region, both with and without taking spatial variation in environmental energy availability into account. Using the South African avifauna as a case study, we find that total and threatened species richness exhibit modest increases with the proportion of protected land. While the protected area network should be expanded, it is essential that conservation efforts also focus on maintaining biodiversity in the wider unprotected landscape that supports high species richness.
Bare skin, blood and the evolution of primate colour vision
Authors: Changizi Mark A , Zhang Qiong , Shimojo Shinsuke
Published: February 2006

We investigate the hypothesis that colour vision in primates was selected for discriminating the spectral modulations on the skin of conspecifics, presumably for the purpose of discriminating emotional states, socio-sexual signals and threat displays. Here we show that, consistent with this hypothesis, there are two dimensions of skin spectral modulations, and trichromats but not dichromats are sensitive to each. Furthermore, the M and L cone maximum sensitivities for routine trichromats are optimized for discriminating variations in blood oxygen saturation, one of the two blood-related dimensions determining skin reflectance. We also show that, consistent with the hypothesis, trichromat primates tend to be bare faced.